Changes of protists, which were categorized into different functional groups primarily according to their feeding habits, in two full-scale municipal wastewater treatment systems experiencing sludge bulking were inves...Changes of protists, which were categorized into different functional groups primarily according to their feeding habits, in two full-scale municipal wastewater treatment systems experiencing sludge bulking were investigated over a period of 14 months. Protist biomass represented 3.7% to 5.2% of total biomass on average under normal sludge conditions, and the percentage increased significantly （p 〈 0.05） under sludge bulking conditions. The biomass of Chilodonella spp., capable of eating filamentous bacteria, tended to decrease in both systems when sludge bulking occurred, showing that the abnormal growth of filamentous bacteria did not lead to a biomass bloom of this group of protists. On the other hand, the bactivorous protists represented more than 96% of total protist biomass, and the biomass of this group, particularly the attached ciliates, increased significantly （p 〈 0.05） when sludge bulking occurred. The significant increase of the attached ciliates may have possibly facilitated the growth of filamentous bacteria through selectively preying on non-filamentous bacteria and further exacerbated sludge bulking. The redundancy analysis and correlation analysis results showed that the biomass changes of the attached ciliates were primarily related to the sludge volume index and to some extent related to five-day biochemical oxygen demand loading and hydraulic retention time.展开更多
Climate change has had an unprecedented impact on lake ecosystems around the globe and has both direct and indirect consequences on lake structure and mineralization. These changes are threatening the unique biodivers...Climate change has had an unprecedented impact on lake ecosystems around the globe and has both direct and indirect consequences on lake structure and mineralization. These changes are threatening the unique biodiversity that lake ecosystems currently support. Siberia is experiencing one of the greatest impacts of climate change in the world, with exceptional warming in the north and increasing aridity in the south. Lakes in southern West Siberia, including saline and hypersaline waterbodies within endorheic basins, remain unexplored in terms of the biodiversity of the microbial eukaryotes inhabiting them. In this study, we investigated the taxonomic and functional diversity of planktonic protist communities in saline and hypersaline lakes (22–220‰) in southern Western Siberia through Illumina 18S rDNA amplicon sequencing. Taxonomic diversity was represented by the Amoebozoa, Archaeplastida, Cryptista, Excavata, Haptista, Obazoa, Provora, and TSAR supergroups, and varied significantly among lakes of different salinities. Salinity has been shown to be an important determinant that directly influences the composition and uniqueness of protist communities. The co-occurrence network analysis revealed a decrease in the complexity of the network of protist communities with increasing salinity. The taxonomic diversity of protists in lakes determines functional diversity, which is expressed as the relative abundance of free-living heterotrophs, phototrophs, and parasites. Phototrophs dominated the delta-hypersaline waters, and free-living heterotrophs dominated the alpha- and beta-hypersaline lakes. The parasite amplicon sequence variants (ASVs) were affiliated mainly with mixohaline and beta-hypersaline lakes.展开更多
Plant growth-promoting rhizobacteria(PGPR)have been widely used for the promotion of plant performance.Predatory protists can influence the taxonomic and functional composition of rhizosphere bacteria.However,research...Plant growth-promoting rhizobacteria(PGPR)have been widely used for the promotion of plant performance.Predatory protists can influence the taxonomic and functional composition of rhizosphere bacteria.However,research on the impact of the interaction between protist and PGPR on plant performance remains at a very early stage.Here,we examined the impacts of individual inoculation of protist(Colpoda inflata,Dimastigella trypaniformis,or Vermamoeba vermiformis)or the PGPR strain Bacillus velezensis SQR9 as well as the co-inoculation of the protist C.inflata and B.velezensis SQR9 on the growth of tomato plants.We found that all individual protists and Bacillus could promote plant growth compared to the control with no microbe inoculation,with the co-inoculation of C.inflata and B.velezensis SQR9 achieving the greatest performance,including plant height,fresh weight,and dry weight.Different protists harbored distinct rhizosphere bacterial communities,with the co-inoculation of protist and Bacillus resulting in the lowest bacterial diversity and driving significant changes in community structure and composition,particularly by increasing the relative abundance of Proteobacteria.Random forest model highlighted Cellvibrio as the most important bacterial predictor of plant growth,which was enriched after protist inoculation,especially after the mixed inoculation of protist and Bacillus.We further found that bacterial functional genes of nitrogen metabolism were the key determinants of plant growth.These results indicate that the interaction between protists and Bacillus can support plant growth by reshaping rhizosphere bacterial community composition and function.Understanding the interaction mechanisms between protist and PGPR is crucial for their effective utilization in sustainable agriculture.展开更多
Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity a...Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.展开更多
Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.Ho...Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.展开更多
Protists,which include eukaryotic algae and protozoa,are crucially important for biogeochemical cycling and the aquatic food web but are sensitive to environmental fluctuations.Despite investigations in the 1970s,prot...Protists,which include eukaryotic algae and protozoa,are crucially important for biogeochemical cycling and the aquatic food web but are sensitive to environmental fluctuations.Despite investigations in the 1970s,protist diversity and biogeographic characteristics in the Tibetan Plateau are poorly understood.Within the framework of a regional survey of protist diversity,we used high-throughput amplicon sequencing to investigate the composition and spatiotemporal turnover of protist communities along the Yarlung Zangbo River,a representative aquatic habitat of the Tibetan Plateau.In total,we detected 9,959 amplicon sequence variants in protist communities along the river and associated lakes and wetlands.The alpha diversity of protists was highest in spring and declined in the autumn.Moreover,alpha diversity was much higher in the middle and upstream reaches and tributaries than in the connected lakes and wetlands.We discovered spatiotemporal heterogeneity in the composition of protist communities across the seasons.Bacillariophyta predominated in protist communities in cold seasons(spring and autumn)and colder(high-altitude)areas,whereas Ciliophora and Cercozoa species predominated in the warm season(summer)and warmer(low-altitude)areas.Of the environmental factors,altitude,turbidity and salinity correlated with spatiotemporal dissimilarities among protist communities.The breadth of the habitat niche was restricted by turbidity and altitude in river areas and by salinity in lake and wetland areas.Co-occurrence network analysis suggested that protist communities in the Yarlung Zangbo River were substantially more complex in the warm season than in the cold seasons,and that amplicon sequence variants belonging to Ochrophyta,Chlorophyta,and Ciliophora contributed greatly to the stability of the cooccurrence network.In summary,this study provides a comprehensive overview of the spatiotemporal dynamics of protist diversity in the Yarlung Zangbo River and improves our understanding of the environmental adaptation of protists living in aquatic habitats of the Tibetan Plateau.展开更多
Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological, environmental,evolutionary and basic biological studies. In the present study, we investigated the living cha...Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological, environmental,evolutionary and basic biological studies. In the present study, we investigated the living characteristics, infraciliature, nuclear apparatus, ontogenesis and phylogenetic position of a marine hypotrichous ciliate, Apokeronopsis wrighti Long et al., 2008, which was isolated from coastal waters in Shenzhen, China. The new isolate resembles the type population in terms of morphological characteristics, morphometrics, and SSU rRNA gene sequence that is with a 99.7% similarity. Ontogenesis of A. wrighti is characterized by oral primordium for the proter as well as marginal and dorsal kineties anlagen in both filial products formed de novo, and the cirral row arranged along the paroral and endoral arises from several anterior frontoventral-transverse cirral streaks. Phylogenetic analyses based on SSU and concatenated gene data suggest that five species of Apokeronopsis form a monophyletic clade, and the genus Apokeronopsis is closely related to Thigmokeronopsis and Metaurostylopsis.展开更多
Widespread forest fires pose significant challenges to the diverse communities of soil-dwelling organisms and the multiple ecosystem functions they support.However,whether the biodiversity and interactions of various ...Widespread forest fires pose significant challenges to the diverse communities of soil-dwelling organisms and the multiple ecosystem functions they support.However,whether the biodiversity and interactions of various taxonomic groups respond to fire consistently in terms of direction and extent,and their relative role in regulating post-fire soil functioning,remains largely unexplored.In this study,we investigated whether the diversity and co-occurrence networks of soil organisms across various trophic levels(including bacteria,fungi,protists,and invertebrates)in subtropical forests exhibit consistent responses to fire.Furthermore,we investigated their contribution to regulating soil multifunctionality,which is measured by a range of soil extracellular enzyme activities,available nutrients and reduced potential fungal plant pathogens.Our findings revealed that fire led to a decline in the richness of fungi,protists,and invertebrates,without significantly impacting bacterial richness.Fire also simplified the microbial co-occurrence networks while complexifying the invertebrate networks.Interestingly,soil multifunctionality tended to decrease with the richness of lower-trophic communities(i.e.,bacteria),whereas it increased with that of high-trophic communities(i.e.,protists and invertebrates).Moreover,fire indirectly influenced soil multifunctionality by altering biodiversity and network complexity,particularly pronounced in high-trophic communities.Overall,our results underscored the divergent vulnerability of biodiversity and networks to fires across taxa groups,highlighting the crucial role of biodiversity and interactions of higher trophic taxa groups in shaping the recovery and functionality of fire-affected soils.展开更多
Coastal and estuarine protists are frequently exposed to salinity undulation.While the tolerance and stress responses of microalgae to salinity have been extensively studied,there have been scarce studies on the physi...Coastal and estuarine protists are frequently exposed to salinity undulation.While the tolerance and stress responses of microalgae to salinity have been extensively studied,there have been scarce studies on the physiological response of heterotrophic protists to salinity stressing.In this study,we investigated the physiological response of the heterotrophic ciliate Gastrostyla setifera to a salinity of 3,via a transcriptomic approach.The first transcriptome of genus Gastrostyla was obtained utilizing a group of manually isolated ciliate individuals(cells)and RNA-seq technique.The completeness of the transcriptome was verified.Differentially expressed gene(DEG)analysis was performed among the transcriptomes of G.setifera acclimated in saline water(salinity 3)and those cultured in fresh water.The results demonstrated a significant alternation in gene transcription,in which the ciliate exhibits a transcripttomic acclimation in responding salinity stressing.The up-regulated DEGs were enriched in the pathways of cytoskeleton proteins,membrane trafficking,protein kinases and protein phosphatases.These may represent enhanced functions of ion transport,stress response and cell protections.Pathways involved in energy metabolism and biosynthesis were markedly down-regulated,reflecting decreased cell activity.Particularly,we detected significantly down-regulated genes involved in several pathways of amino acid catabolism,which may lead to accumulation of amino acids in the ciliate cell.Amino acid could act as compatible solutes in the cytoplasm to maintain the osmotic balance in saline water.Overall,this work is an initial exploration to the molecular basis of the heterotrophic protist responding to salinity stressing.The result sheds light on the mechanisms of enhancement of cell protection,reduction of cell activity,and osmotic pressure regulation in ciliates acclimated to salinity.展开更多
Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Mup...Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Muping Marine Ranch(MR)which is along the littoral zone of northern Yellow Sea of China,environmental DNA methods were employed to investigate the diversity and seasonal dynamics of near shore planktonic protists in response to mariculture.Through an integrated analysis of functional groups and a comparison to adjacent sea areas,we found a dominance of harmful algae blooms(HAB)species nearshore MR,and a significant reduction in the diversity of planktonic protists including photosynthetic,heterotrophic and parasitic groups.High nutrient and low salinity were suggested to drive the dominance of HAB species nearshore MR,which in return might inhibit predators,saprophytes and algal parasites.Our investigations revealed an Olisthodiscus luteus outbreak in spring,as well as significant seasonal variations in the planktonic protist community,which might be caused by the changes of temperature.The offshore hypoxia reduced the abundance of phytoplankton but increased mixotrophs and animal parasites of the protistan community nearshore MR.This study highlights the influence of mariculture on the overall community function of planktonic protists,and is helpful to assess the mariculture's impact on water health.展开更多
The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during...The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.展开更多
Facilitated by the high-throughput sequencing(HTS)technique,the importance of protists to aquatic systems has been widely acknowledged in the last decade.However,information of protistan biotic interactions and season...Facilitated by the high-throughput sequencing(HTS)technique,the importance of protists to aquatic systems has been widely acknowledged in the last decade.However,information of protistan biotic interactions and seasonal dynamics is much less known in the coast ecosystem with intensive anthropic disturbance.In this study,year-round changes of protist community composition and diversity in the coastal water of Yantai,a city along the northern Yellow Sea in China,were investigated using HTS for the V4 region of 18S rDNA.The interactions among protist groups were also analyzed using the co-occurrence network.Data analyses showed that Alveolata,Chlorophyta,and Stramenopiles are the most dominant phytoplanktonic protists in the investigated coastal area.The community composition displayed strong seasonal variation.The abundant families Dino-Group-I-Clade-1 and Ulotrichales_X had higher proportions in spring and summer,while Bathycoccaceae exhibited higher ratios in autumn and winter.Alpha diversities(Shannon and Simpson)were the highest in autumn and the lowest in spring(ANOVA test,P<0.05).Nutrients(SiO42−,PO43−),total organic carbon(TOC),and pH seemed to drive the variation of alpha diversity,while temperature,PO43−and TON were the most significant factors influencing the whole protist community.Co-variance network analyses reveal frequent co-occurrence events among ciliates,chlorophytes and dinoflagellate,suggesting biotic interactions have been induced by predation,parasitism and mixotrophy.展开更多
The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Re...The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Results show that total Chl a levels in the surface seawater of the Sanggou Bay generally range from 0.10 to 20.46μg/L, with an average value of 2.13 μg/L. Nano-phytoplankton was the most important size-fraction and accounted for about 65.1% of total Chl a. In order to evaluate the importance of the ＂protozoan trophic link＂ for energy transfer from the microbial loop to filter-feeding feeders, Zhikong scallop Chlamys farreri was then offered a natural planktonic community as potential prey. Results show that scallops obtained carbon source from natural plankton with the rate of 11 033.05 μg/（g·d）. Protists（nanoflagellates and ciliates） were the dominant source of carbon retained by scallop（48.78%）. The microbial loop provided 58.45% of the carbon source for farmed scallops. These results indicate that the microbial loop represent a valuable trophic resource in mariculture system of the Sanggou Bay.展开更多
Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralizatio...Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralization process.Magnetosomes have recently also been found in unicellular eukaryotes,which are referred to as magnetically responsive protists(MRPs).The magnetosomes have three origins in MRPs.In this study,we characterized a MTB-grazing ciliated MRP that was magnetically collected from intertidal sediment of Huiquan Bay,Qingdao,China.Based on 18S rRNA gene sequence analysis,the ciliated MRP was tentatively identified as Uronemella parafi lificum HQ.Using transmission electron microscopy,we observed that magnetosomes having 2-3 shapes were randomly distributed within this ciliate.Energydispersive X-ray spectroscopy and high-resolution transmission electron microscopy images of the magnetosomes were consistent with them being composed of magnetite.Magnetosomes having the same shape and mineral composition were also detected in MTB that occurred in the same environment as the ciliated MRP.Statistical analysis showed that the size and shape of the magnetosomes in the ciliated MRP were similar to those in MTB.The results suggest that this ciliated MRP can graze,ingest,and digest various types of MTB.It is certainly worth noting that this is the first record of MRPs in Asian aquatic sediment and suggesting they might be widely distributed.These results also support the assertion that MRPs probably contribute to the ecological cycles of iron,and expand possibilities for research into the mechanism of magnetoreception in eukaryotes.展开更多
The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surve...The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref展开更多
In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmenta...In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmental stress were investigated in a shrimp-farming pond near Qingdao, China during a complete shrimp-culture cycle （May to October 2002）. A clear temporal succession in species distribution was found over the complete farming cycle. For example, before the introduction of the shrimp larvae there was low-variability of species distribution in the protist communities whereas during the stages immediately after, there was higher variability in species composition. Multiple linear/logistic regression analyses demonstrate that 12 protist taxa （e.g., Gyrodinium spirale, Teleaulax acuta, Prorocentrum spp. and Mesodinium pupula） were related to the nutrients, in particular ammonia and phosphates, alone or in combination with water temperature. These results suggest that temporal variations in species distribution of planktonic protist communities might be used in assessing water quality of semi-enclosed mariculture waters.展开更多
Marine ciliates play important roles not only in linking the microbial loop to the classic pelagic and benthic food chains but also in regenerating nutrients,yet how dietary nutrient imbalance impacts their nutrient r...Marine ciliates play important roles not only in linking the microbial loop to the classic pelagic and benthic food chains but also in regenerating nutrients,yet how dietary nutrient imbalance impacts their nutrient regeneration has not been thoroughly addressed.The growth and physiological responses of Euplotes vannus to low dietary nitrogen(LN)and low dietary phosphorus(LP)conditions were studied,with the bacterium Pseudomonas putida as prey.Feeding on LN prey reduced the growth rate of E.vannus.Dietary nutrient limitation changed the types and quantities of nutrient recycling.Feeding on LP prey enhanced dissolved organic carbon excretion but reduced orthophosphate excretion,whereas feeding on LN prey generally resulted in decreases in the excretion rate in all N forms(ammonium,urea,and nitrate).In addition,the proportion of ammonium in regenerated N increased significantly under the LN condition.These findings indicate that a nutrient-imbalanced diet triggers E.vannus to retain limited macronutrients and promotes the recycling of excessive macronutrients,which may potentially form positive and negative feedback to ambient N and P limitations,respectively.展开更多
Bacterial and viral therapies of cancer are highly promising, yet their mechanisms are incompletely understood, hindering their improvement and application. In this paper, We 1) review briefly the genesis and progress...Bacterial and viral therapies of cancer are highly promising, yet their mechanisms are incompletely understood, hindering their improvement and application. In this paper, We 1) review briefly the genesis and progress of bacterial and viral therapies of cancer;2) compare and evaluate the proposed mechanisms of bacterial and viral therapies of cancer and present the unifying mechanism that bacteria/viruses stimulate cancer cells to produce antibacterial/antiviral proteins, which also serve as the responsive cancer antigens triggering host anticancer immune response;and 3) provide a perspective on the exploitation of non-human and non-animal bacteria and viruses and other microorganisms, particularly protist-infecting bacteria and viruses and bacterial/cyanobacterial viruses (bacteriophage/phage and cyanophage), for cancer treatment and prevention.展开更多
Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we ...Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.展开更多
Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insu...Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insufficiency of molecular data.With morphological and multi-gene-based molecular data presented here,the evolutionary phylogeny of several Scuticocili-atia taxa that were hitherto especially poorly defined is analyzed and discussed.The results indicate:(1)all scuticociliates cluster into two well supported and one poorly supported group,representing three order-level taxa;(2)with the support of both morphological and molecular data,a new family Homalogastridae fam.nov.is proposed in the order Philasterida;(3)Parauronema is formally transferred to Uronematidae and Potomacus is treated as incertae sedis in the order Philasterida,therefore Parauronematidae is proposed to be a junior synonym of Uronematidae;(4)the genus Madsenia and the species Parauronema longum and Pseudocyclidium longum are treated as incertae sedis,while the genus Protophyra should be maintained in the family Ancistridae.In addition,the putative secondary structure of internal transcribed spacer 2(ITS2)of representative taxa from the three orders of Scuticociliatia are analyzed,and consensus structures and nucleotide composi-tion in each order are exhibited.展开更多
基金supported by the Chinese Academy of Sciences (No. KZCX2-YW-JC407)the National Natural Science Foundation of China (No. 20921140094)
文摘Changes of protists, which were categorized into different functional groups primarily according to their feeding habits, in two full-scale municipal wastewater treatment systems experiencing sludge bulking were investigated over a period of 14 months. Protist biomass represented 3.7% to 5.2% of total biomass on average under normal sludge conditions, and the percentage increased significantly （p 〈 0.05） under sludge bulking conditions. The biomass of Chilodonella spp., capable of eating filamentous bacteria, tended to decrease in both systems when sludge bulking occurred, showing that the abnormal growth of filamentous bacteria did not lead to a biomass bloom of this group of protists. On the other hand, the bactivorous protists represented more than 96% of total protist biomass, and the biomass of this group, particularly the attached ciliates, increased significantly （p 〈 0.05） when sludge bulking occurred. The significant increase of the attached ciliates may have possibly facilitated the growth of filamentous bacteria through selectively preying on non-filamentous bacteria and further exacerbated sludge bulking. The redundancy analysis and correlation analysis results showed that the biomass changes of the attached ciliates were primarily related to the sludge volume index and to some extent related to five-day biochemical oxygen demand loading and hydraulic retention time.
基金funded by the Tyumen Oblast within the framework of the project of the West Siberian Interregional Scientific and Educational Center No.89-DON(2).
文摘Climate change has had an unprecedented impact on lake ecosystems around the globe and has both direct and indirect consequences on lake structure and mineralization. These changes are threatening the unique biodiversity that lake ecosystems currently support. Siberia is experiencing one of the greatest impacts of climate change in the world, with exceptional warming in the north and increasing aridity in the south. Lakes in southern West Siberia, including saline and hypersaline waterbodies within endorheic basins, remain unexplored in terms of the biodiversity of the microbial eukaryotes inhabiting them. In this study, we investigated the taxonomic and functional diversity of planktonic protist communities in saline and hypersaline lakes (22–220‰) in southern Western Siberia through Illumina 18S rDNA amplicon sequencing. Taxonomic diversity was represented by the Amoebozoa, Archaeplastida, Cryptista, Excavata, Haptista, Obazoa, Provora, and TSAR supergroups, and varied significantly among lakes of different salinities. Salinity has been shown to be an important determinant that directly influences the composition and uniqueness of protist communities. The co-occurrence network analysis revealed a decrease in the complexity of the network of protist communities with increasing salinity. The taxonomic diversity of protists in lakes determines functional diversity, which is expressed as the relative abundance of free-living heterotrophs, phototrophs, and parasites. Phototrophs dominated the delta-hypersaline waters, and free-living heterotrophs dominated the alpha- and beta-hypersaline lakes. The parasite amplicon sequence variants (ASVs) were affiliated mainly with mixohaline and beta-hypersaline lakes.
基金supported by the National Natural Science Foundation of China(Nos.42377296 and 42107141)the National Key Research and Development Program of China(Nos.2023YFD1901402 and 2023YFD1901105)the Fundamental Research Funds for the Central Universities,China(No.YDZX2025046).
文摘Plant growth-promoting rhizobacteria(PGPR)have been widely used for the promotion of plant performance.Predatory protists can influence the taxonomic and functional composition of rhizosphere bacteria.However,research on the impact of the interaction between protist and PGPR on plant performance remains at a very early stage.Here,we examined the impacts of individual inoculation of protist(Colpoda inflata,Dimastigella trypaniformis,or Vermamoeba vermiformis)or the PGPR strain Bacillus velezensis SQR9 as well as the co-inoculation of the protist C.inflata and B.velezensis SQR9 on the growth of tomato plants.We found that all individual protists and Bacillus could promote plant growth compared to the control with no microbe inoculation,with the co-inoculation of C.inflata and B.velezensis SQR9 achieving the greatest performance,including plant height,fresh weight,and dry weight.Different protists harbored distinct rhizosphere bacterial communities,with the co-inoculation of protist and Bacillus resulting in the lowest bacterial diversity and driving significant changes in community structure and composition,particularly by increasing the relative abundance of Proteobacteria.Random forest model highlighted Cellvibrio as the most important bacterial predictor of plant growth,which was enriched after protist inoculation,especially after the mixed inoculation of protist and Bacillus.We further found that bacterial functional genes of nitrogen metabolism were the key determinants of plant growth.These results indicate that the interaction between protists and Bacillus can support plant growth by reshaping rhizosphere bacterial community composition and function.Understanding the interaction mechanisms between protist and PGPR is crucial for their effective utilization in sustainable agriculture.
基金supported by the Natural Resources Science and Technology Innovation Project of Fujian Province,China(No.KY-090000-04-2022-012)the National Natural Science Foundation of China(Nos.42077041 and 42377301)+1 种基金the National Natural Science Foundation of Fujian Province,China(No.2021J011038)the Talent Introduction Program of Minjiang University,China(No.MJY20012).
文摘Soil microbiomes are significant for biodiversity,crucial for ecosystem functions,and vital for the health of various organisms.Nevertheless,the impacts of season and plant species shifts on soil microbial diversity and community assembly are still poorly understood.This study explored soil bacterial,fungal,and protistan communities during summer and winter in a coastal wetland affected by Spartina alterniflora invasion and subsequent Cyperus malaccensis or Kandelia obovata restoration.The results showed that bacterial,fungal,and protistan diversity were 2.63%,40.3%,and 9.90%higher in winter than in summer,respectively.Plant species had a distinct impact on microbial diversity.Notably,K.obovata restoration significantly increased bacterial diversity,but decreased protistan diversity,with no effect on fungal diversity when compared to S.alterniflora invasion.Season and plant species both significantly influenced the community structure of bacteria,fungi,and protists.However,protistan community structure was more sensitive to season compared to the structure of bacterial and fungal communities.The complexity of co-occurrence networks within or among bacteria,fungi,and protists was higher in winter than in summer.Bacterial and protistan community assembly was primarily driven by stochastic processes,while fungal assembly was dominated by deterministic processes.Bacterial and protistan community assembly exhibited lower stochasticity in winter compared to summer,suggesting a more deterministic assembly of communities during winter.Our findings highlight the critical role of season and plant species in regulating microbial communities,revealing higher microbial diversity,network complexity,and determinism in community assembly during winter compared to summer in a subtropical coastal wetland.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.XDA28110100 and XDA28020202)the National Key Research and Development Program of China(No.2022YFD1500203)+3 种基金the National Natural Science Foundation of China(No.42177332)the China Agriculture Research System(Nos.CARS-03 and CARS-52)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2023325)the Anhui Provincial Key Research and Development Project,China(No.2023n06020056).
文摘Straw return is the main practice used to increase soil organic matter(SOM)in agricultural ecosystems.To increase the efficiency of straw conversion to SOM,a large number of microbial inoculants have been developed.However,their effects are poor because of the complex water and temperature conditions,especially under sodic conditions.Small molecules can rapidly shift soil microbial communities and improve their ability to transform exogenous organic matter into SOM,providing a new direction for promoting high-efficiency straw conversion into SOM.In this study,we conducted a^(13)C-labeled straw degradation experiment using small molecules derived from lignin(LSMs)and humus(HSMs)as activators,investigating their effects on the microbial communities and formation of newly formed mineral-associated(^(13)C-MAOM)and particulate(^(13)C-POM)organic matter from^(13)C-labeled straw in both sodic and non-sodic soils.The^(13)C-labeled straw was mainly converted into^(13)C-MAOM,accounting for 73.97%–92.67%of the newly formed SOM.Biopolymer-derived small molecules decreased the exchangeable sodium percentage(ESP),but increased contents of^(13)C-MAOM and^(13)C-POM by shifting microbial communities,strengthening microbial cross-trophic interactions,enhancing enzyme activities,and increasing microbial residues in both soils.Addition of HSMs had greater impacts on^(13)C-MAOM formation than LSM addition.The^(13)C-MAOM and^(13)C-POM formation negatively correlated with ESP,but positively correlated with microbial cross-trophic interactions and enzyme activities in both soils.Our results suggest that biopolymer-derived small molecules promote^(13)C-MAOM and^(13)C-POM formation associated with microbial cross-trophic interactions between protistan predators and primary decomposers.Our study provides scientific support for future attempts to stimulate microbial cross-trophic interactions for boosting SOM accumulation under stressed conditions.
基金supported by the National Natural Science Foundation of China(Grant No.32070418 to S.B.)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0304 to W.M.)the High-Level Talent Training Program for postgraduate of Tibet University(Grant No.2019-GSP-S049 to P.Z.).
文摘Protists,which include eukaryotic algae and protozoa,are crucially important for biogeochemical cycling and the aquatic food web but are sensitive to environmental fluctuations.Despite investigations in the 1970s,protist diversity and biogeographic characteristics in the Tibetan Plateau are poorly understood.Within the framework of a regional survey of protist diversity,we used high-throughput amplicon sequencing to investigate the composition and spatiotemporal turnover of protist communities along the Yarlung Zangbo River,a representative aquatic habitat of the Tibetan Plateau.In total,we detected 9,959 amplicon sequence variants in protist communities along the river and associated lakes and wetlands.The alpha diversity of protists was highest in spring and declined in the autumn.Moreover,alpha diversity was much higher in the middle and upstream reaches and tributaries than in the connected lakes and wetlands.We discovered spatiotemporal heterogeneity in the composition of protist communities across the seasons.Bacillariophyta predominated in protist communities in cold seasons(spring and autumn)and colder(high-altitude)areas,whereas Ciliophora and Cercozoa species predominated in the warm season(summer)and warmer(low-altitude)areas.Of the environmental factors,altitude,turbidity and salinity correlated with spatiotemporal dissimilarities among protist communities.The breadth of the habitat niche was restricted by turbidity and altitude in river areas and by salinity in lake and wetland areas.Co-occurrence network analysis suggested that protist communities in the Yarlung Zangbo River were substantially more complex in the warm season than in the cold seasons,and that amplicon sequence variants belonging to Ochrophyta,Chlorophyta,and Ciliophora contributed greatly to the stability of the cooccurrence network.In summary,this study provides a comprehensive overview of the spatiotemporal dynamics of protist diversity in the Yarlung Zangbo River and improves our understanding of the environmental adaptation of protists living in aquatic habitats of the Tibetan Plateau.
基金supported by the Natural Science Foundation of Shaanxi Province(Nos.2023-JC-QN-0214,2023JC-QN-0185)the Postdoctoral Science Foundation of Shaanxi Province(No.2023BSHEDZZ199)the Fundamental Research Funds for the Central Universities(No.GK202207019)。
文摘Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological, environmental,evolutionary and basic biological studies. In the present study, we investigated the living characteristics, infraciliature, nuclear apparatus, ontogenesis and phylogenetic position of a marine hypotrichous ciliate, Apokeronopsis wrighti Long et al., 2008, which was isolated from coastal waters in Shenzhen, China. The new isolate resembles the type population in terms of morphological characteristics, morphometrics, and SSU rRNA gene sequence that is with a 99.7% similarity. Ontogenesis of A. wrighti is characterized by oral primordium for the proter as well as marginal and dorsal kineties anlagen in both filial products formed de novo, and the cirral row arranged along the paroral and endoral arises from several anterior frontoventral-transverse cirral streaks. Phylogenetic analyses based on SSU and concatenated gene data suggest that five species of Apokeronopsis form a monophyletic clade, and the genus Apokeronopsis is closely related to Thigmokeronopsis and Metaurostylopsis.
基金financially supported by the National Natural Science Foundation of China(Nos.42377288,32201528)the Natural Science Foundation of Fujian Province(No.2021J05040).
文摘Widespread forest fires pose significant challenges to the diverse communities of soil-dwelling organisms and the multiple ecosystem functions they support.However,whether the biodiversity and interactions of various taxonomic groups respond to fire consistently in terms of direction and extent,and their relative role in regulating post-fire soil functioning,remains largely unexplored.In this study,we investigated whether the diversity and co-occurrence networks of soil organisms across various trophic levels(including bacteria,fungi,protists,and invertebrates)in subtropical forests exhibit consistent responses to fire.Furthermore,we investigated their contribution to regulating soil multifunctionality,which is measured by a range of soil extracellular enzyme activities,available nutrients and reduced potential fungal plant pathogens.Our findings revealed that fire led to a decline in the richness of fungi,protists,and invertebrates,without significantly impacting bacterial richness.Fire also simplified the microbial co-occurrence networks while complexifying the invertebrate networks.Interestingly,soil multifunctionality tended to decrease with the richness of lower-trophic communities(i.e.,bacteria),whereas it increased with that of high-trophic communities(i.e.,protists and invertebrates).Moreover,fire indirectly influenced soil multifunctionality by altering biodiversity and network complexity,particularly pronounced in high-trophic communities.Overall,our results underscored the divergent vulnerability of biodiversity and networks to fires across taxa groups,highlighting the crucial role of biodiversity and interactions of higher trophic taxa groups in shaping the recovery and functionality of fire-affected soils.
基金supported by the National Natural Science Foundation of China(Nos.32370488,42176163,31970398 and 31672251)the Youth Innovation Promotion Association of CAS(Nos.2019216 and 2022211).
文摘Coastal and estuarine protists are frequently exposed to salinity undulation.While the tolerance and stress responses of microalgae to salinity have been extensively studied,there have been scarce studies on the physiological response of heterotrophic protists to salinity stressing.In this study,we investigated the physiological response of the heterotrophic ciliate Gastrostyla setifera to a salinity of 3,via a transcriptomic approach.The first transcriptome of genus Gastrostyla was obtained utilizing a group of manually isolated ciliate individuals(cells)and RNA-seq technique.The completeness of the transcriptome was verified.Differentially expressed gene(DEG)analysis was performed among the transcriptomes of G.setifera acclimated in saline water(salinity 3)and those cultured in fresh water.The results demonstrated a significant alternation in gene transcription,in which the ciliate exhibits a transcripttomic acclimation in responding salinity stressing.The up-regulated DEGs were enriched in the pathways of cytoskeleton proteins,membrane trafficking,protein kinases and protein phosphatases.These may represent enhanced functions of ion transport,stress response and cell protections.Pathways involved in energy metabolism and biosynthesis were markedly down-regulated,reflecting decreased cell activity.Particularly,we detected significantly down-regulated genes involved in several pathways of amino acid catabolism,which may lead to accumulation of amino acids in the ciliate cell.Amino acid could act as compatible solutes in the cytoplasm to maintain the osmotic balance in saline water.Overall,this work is an initial exploration to the molecular basis of the heterotrophic protist responding to salinity stressing.The result sheds light on the mechanisms of enhancement of cell protection,reduction of cell activity,and osmotic pressure regulation in ciliates acclimated to salinity.
基金supported by the National Natural Science Foundation of China(Nos.42176163,31970398,and 32370488)the Youth Innovation Promotion Association,CAS(Nos.2019216 and 2022211)。
文摘Mariculture exerts a direct influence on planktonic eukaryotic microorganisms protists.Previous studies have focused on phytoplankton,while the heterotrophic and parasitic protistan groups are unknown.Currently,in Muping Marine Ranch(MR)which is along the littoral zone of northern Yellow Sea of China,environmental DNA methods were employed to investigate the diversity and seasonal dynamics of near shore planktonic protists in response to mariculture.Through an integrated analysis of functional groups and a comparison to adjacent sea areas,we found a dominance of harmful algae blooms(HAB)species nearshore MR,and a significant reduction in the diversity of planktonic protists including photosynthetic,heterotrophic and parasitic groups.High nutrient and low salinity were suggested to drive the dominance of HAB species nearshore MR,which in return might inhibit predators,saprophytes and algal parasites.Our investigations revealed an Olisthodiscus luteus outbreak in spring,as well as significant seasonal variations in the planktonic protist community,which might be caused by the changes of temperature.The offshore hypoxia reduced the abundance of phytoplankton but increased mixotrophs and animal parasites of the protistan community nearshore MR.This study highlights the influence of mariculture on the overall community function of planktonic protists,and is helpful to assess the mariculture's impact on water health.
基金The National Natural Science Foundation of China under contract Nos 40676076 and 30700069the Darwin Initiative Programme under contract No.14-015a grant from the Center of Excellence in Biodiversity Research,King Saud University
文摘The functional groups of planktonic protist communities and their responses to the changes of environmental conditions were investigated in a semi-enclosed shrimp-farming pond in Qingdao,Shandong Province,China,during a six-month study period （a complete shrimp-culture cycle） from May to October 2002.The results reveal that： （1） the protist communities represented five trophic and functional groups of the species identified,about 60% were photoautotrophs,20% algivores,12% bacterivores,5% raptors and about 3% non-selectives;（2） the photoautotrophs,algivores and bacterivores were the primary contributors to the changes in the protist communities in short temporal scales,the succession of dominance typically being bacterivores→photoautotrophs→algivores,with the raptors dominating the protist communities in a single sample （early June）;（3） the photoautotrophs and non-selectives were the primary contributors to the peak of protist abundance in early October whereas the photoautotrophs,bacterivores,raptors and non-selectives mainly gave rise to two bimodal peaks of biomass in July and October respectively;（4） five functional groups of protist communities represented significant correlations with water nutrients （i.e.,NH 3-N,NO 3-N,and PO 4 ）,either alone or in combination with temperature,of which algivores and raptors were strongly correlated with phosphate and the concentration of Chl a,while bacterivores were strongly related to nitrogen and the concentration of bacteria.These findings confirm that planktonic protists are potentially useful bioindicators of water quality in the semi-enclosed mariculture system.
基金the National Natural Science Foundation of China(Nos.31672251,31772413)the Youth Innovation Promotion Association,CAS(No.2019216)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050303)the Key Research Project of Frontier Science,CAS(No.QYZDBSSW-DQC013-1).
文摘Facilitated by the high-throughput sequencing(HTS)technique,the importance of protists to aquatic systems has been widely acknowledged in the last decade.However,information of protistan biotic interactions and seasonal dynamics is much less known in the coast ecosystem with intensive anthropic disturbance.In this study,year-round changes of protist community composition and diversity in the coastal water of Yantai,a city along the northern Yellow Sea in China,were investigated using HTS for the V4 region of 18S rDNA.The interactions among protist groups were also analyzed using the co-occurrence network.Data analyses showed that Alveolata,Chlorophyta,and Stramenopiles are the most dominant phytoplanktonic protists in the investigated coastal area.The community composition displayed strong seasonal variation.The abundant families Dino-Group-I-Clade-1 and Ulotrichales_X had higher proportions in spring and summer,while Bathycoccaceae exhibited higher ratios in autumn and winter.Alpha diversities(Shannon and Simpson)were the highest in autumn and the lowest in spring(ANOVA test,P<0.05).Nutrients(SiO42−,PO43−),total organic carbon(TOC),and pH seemed to drive the variation of alpha diversity,while temperature,PO43−and TON were the most significant factors influencing the whole protist community.Co-variance network analyses reveal frequent co-occurrence events among ciliates,chlorophytes and dinoflagellate,suggesting biotic interactions have been induced by predation,parasitism and mixotrophy.
基金The National Natural Science Foundation of China under contract Nos 41676147 and 41306117the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2016ASKJ02+1 种基金the earmarked fund for Modern Agro-industry Technology Research System under contract No.CARS-48the National Basic Research Program of China under contract No.2011CB409805
文摘The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Results show that total Chl a levels in the surface seawater of the Sanggou Bay generally range from 0.10 to 20.46μg/L, with an average value of 2.13 μg/L. Nano-phytoplankton was the most important size-fraction and accounted for about 65.1% of total Chl a. In order to evaluate the importance of the ＂protozoan trophic link＂ for energy transfer from the microbial loop to filter-feeding feeders, Zhikong scallop Chlamys farreri was then offered a natural planktonic community as potential prey. Results show that scallops obtained carbon source from natural plankton with the rate of 11 033.05 μg/（g·d）. Protists（nanoflagellates and ciliates） were the dominant source of carbon retained by scallop（48.78%）. The microbial loop provided 58.45% of the carbon source for farmed scallops. These results indicate that the microbial loop represent a valuable trophic resource in mariculture system of the Sanggou Bay.
基金Supported by the National Natural Science Foundation of China(Nos.41776130,41776131)the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers(No.U1706208)。
文摘Magnetotactic bacteria(MTB)are a group of prokaryotes having the ability to orient and swim along geomagnetic field lines because they contain intracellular magnetosomes that are synthesized through a biomineralization process.Magnetosomes have recently also been found in unicellular eukaryotes,which are referred to as magnetically responsive protists(MRPs).The magnetosomes have three origins in MRPs.In this study,we characterized a MTB-grazing ciliated MRP that was magnetically collected from intertidal sediment of Huiquan Bay,Qingdao,China.Based on 18S rRNA gene sequence analysis,the ciliated MRP was tentatively identified as Uronemella parafi lificum HQ.Using transmission electron microscopy,we observed that magnetosomes having 2-3 shapes were randomly distributed within this ciliate.Energydispersive X-ray spectroscopy and high-resolution transmission electron microscopy images of the magnetosomes were consistent with them being composed of magnetite.Magnetosomes having the same shape and mineral composition were also detected in MTB that occurred in the same environment as the ciliated MRP.Statistical analysis showed that the size and shape of the magnetosomes in the ciliated MRP were similar to those in MTB.The results suggest that this ciliated MRP can graze,ingest,and digest various types of MTB.It is certainly worth noting that this is the first record of MRPs in Asian aquatic sediment and suggesting they might be widely distributed.These results also support the assertion that MRPs probably contribute to the ecological cycles of iron,and expand possibilities for research into the mechanism of magnetoreception in eukaryotes.
文摘The impact of diflubenzuron (DFB) on Tetrahymena pyriformis, a ciliated protiste was studied. The treatment with DFB at concentrations of 10 and 20 μg/mL could appreciably reduce the growth of the protiste. The surveillance of protozoa′s respiratory metabolism with polarography technique showed a sensitive inhibition of its oxygen consumption, and at 20 μg/mL concentration the oxygen consumption was increased. For any malformation of morphology and perturbation in swimming trajectory, the neutral red coloration was done. This technique (neutral red) showed that there was a toxic effect of DFB on T. pyriformis, especially at the highest concentration; this toxicity was translated by rotatory swimming in same place and the increasing of coloration quantity in digestive vacuoles. Fig 5, Ref
基金The National Natural Science Foundation of China under contract Nos 40676076 and 700069a post-doctoral fellowship of Inha University and a grant from the Center of Excellence in Biodiversity Research, King Saud University
文摘In order to evaluate the relationships between temporal species succession of planktonic protists and physical-chemical parameters in semi-enclosed mariculture waters, species distributions in response to environmental stress were investigated in a shrimp-farming pond near Qingdao, China during a complete shrimp-culture cycle （May to October 2002）. A clear temporal succession in species distribution was found over the complete farming cycle. For example, before the introduction of the shrimp larvae there was low-variability of species distribution in the protist communities whereas during the stages immediately after, there was higher variability in species composition. Multiple linear/logistic regression analyses demonstrate that 12 protist taxa （e.g., Gyrodinium spirale, Teleaulax acuta, Prorocentrum spp. and Mesodinium pupula） were related to the nutrients, in particular ammonia and phosphates, alone or in combination with water temperature. These results suggest that temporal variations in species distribution of planktonic protist communities might be used in assessing water quality of semi-enclosed mariculture waters.
基金The Natural Science Foundation of Guangdong under contract No.2021A1515011384。
文摘Marine ciliates play important roles not only in linking the microbial loop to the classic pelagic and benthic food chains but also in regenerating nutrients,yet how dietary nutrient imbalance impacts their nutrient regeneration has not been thoroughly addressed.The growth and physiological responses of Euplotes vannus to low dietary nitrogen(LN)and low dietary phosphorus(LP)conditions were studied,with the bacterium Pseudomonas putida as prey.Feeding on LN prey reduced the growth rate of E.vannus.Dietary nutrient limitation changed the types and quantities of nutrient recycling.Feeding on LP prey enhanced dissolved organic carbon excretion but reduced orthophosphate excretion,whereas feeding on LN prey generally resulted in decreases in the excretion rate in all N forms(ammonium,urea,and nitrate).In addition,the proportion of ammonium in regenerated N increased significantly under the LN condition.These findings indicate that a nutrient-imbalanced diet triggers E.vannus to retain limited macronutrients and promotes the recycling of excessive macronutrients,which may potentially form positive and negative feedback to ambient N and P limitations,respectively.
文摘Bacterial and viral therapies of cancer are highly promising, yet their mechanisms are incompletely understood, hindering their improvement and application. In this paper, We 1) review briefly the genesis and progress of bacterial and viral therapies of cancer;2) compare and evaluate the proposed mechanisms of bacterial and viral therapies of cancer and present the unifying mechanism that bacteria/viruses stimulate cancer cells to produce antibacterial/antiviral proteins, which also serve as the responsive cancer antigens triggering host anticancer immune response;and 3) provide a perspective on the exploitation of non-human and non-animal bacteria and viruses and other microorganisms, particularly protist-infecting bacteria and viruses and bacterial/cyanobacterial viruses (bacteriophage/phage and cyanophage), for cancer treatment and prevention.
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA24020104,XDA28110100,XDA28020203)the National Key R&D Program of China(Grant Nos.2022YFD1500203,2022YFD1500401)+2 种基金the China Agriculture Research System(Grant Nos.CARS-03,CARS-52)the National Natural Science Foundation of China(Grant No.42177332)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2023325).
文摘Protists are essential components of the rhizosphere microbiome,which is crucial for plant growth,but little is known about the relationship between plant growth and rhizosphere protists under salinity stress.Here we investigated wheat(Triticum aestivum L.)rhizosphere protistan communities under naturally occurring salinity(NOS)and irrigation-reduced salinity(IRS),and linked a plant salinity stress index(PSSI)to different protistan groups in a nontidal coastal saline soil.We found that the PSSI was significantly correlated with rhizosphere cercozoan communities(including bacterivores,eukaryvores,and omnivores)and that these communities were important predictors of the PSSI.Structural equation modeling suggested that root exudation-induced change in bacterial community composition affected the communities of bacterivorous and omnivorous Cercozoa,which were significantly associated with the PSSI across wheat cultivars.Network analysis indicated more complex connections between rhizosphere bacteria and their protistan predators under IRS than under NOS,implying that alleviation of salinity stress promotes the predation of specific cercozoans on bacteria in rhizospheres.Moreover,the Cercomonas directa inoculation was conducive to alleviation of salinity stress.Taken together,these results suggest that the physiological response of wheat plants to salinity stress is closely linked to rhizosphere Cercozoa through trophic regulation within the rhizosphere microbiome.
基金supported by Laoshan Laboratory(No.LSKJ20220320001)the National Natural Science Foundation of China(Project numbers:32030015,32100404,32100382)+2 种基金the Natural Science Foundation of Shandong Province(Project numbers:ZR2021QC045,ZR2021QC104)Young Elite Scientists Sponsorship Program by CAST(Project number:2022QNRC001)a supporting project(Project number:RSP2025R10)at King Saud University,Saudi Arabia.
文摘Scuticociliatia is one of the most species-rich subclasses in the phylum Ciliophora.The evolutionary relationships among Scuticociliatia groups have long been very unclear due to the homogeneity of morphology and insufficiency of molecular data.With morphological and multi-gene-based molecular data presented here,the evolutionary phylogeny of several Scuticocili-atia taxa that were hitherto especially poorly defined is analyzed and discussed.The results indicate:(1)all scuticociliates cluster into two well supported and one poorly supported group,representing three order-level taxa;(2)with the support of both morphological and molecular data,a new family Homalogastridae fam.nov.is proposed in the order Philasterida;(3)Parauronema is formally transferred to Uronematidae and Potomacus is treated as incertae sedis in the order Philasterida,therefore Parauronematidae is proposed to be a junior synonym of Uronematidae;(4)the genus Madsenia and the species Parauronema longum and Pseudocyclidium longum are treated as incertae sedis,while the genus Protophyra should be maintained in the family Ancistridae.In addition,the putative secondary structure of internal transcribed spacer 2(ITS2)of representative taxa from the three orders of Scuticociliatia are analyzed,and consensus structures and nucleotide composi-tion in each order are exhibited.
