Microbial growth causes lamb spoilage.This study explored the spoilage ability of Latilactobacillus sakei,Serratia proteamaculans and Hafnia proteus in vacuum-packed raw lamb,including growth ability,degradation of pr...Microbial growth causes lamb spoilage.This study explored the spoilage ability of Latilactobacillus sakei,Serratia proteamaculans and Hafnia proteus in vacuum-packed raw lamb,including growth ability,degradation of protein and lipid,and change of volatile organic compounds(VOCs)profile,meanwhile screened the key VOCs produced by the targeted strains with meat background excluding,finally confirmed the volatile spoilage marker of vacuum-packaged lamb by comparing with our previous work.The results showed that L.sakei,S.proteamaculans and H.proteus had excellent growth ability.L.sakei inoculated group significantly reduced the pH value,showed higher trichloroacetic acid-soluble peptides content,and excellently degraded sarcoplasmic and myofibrillar proteins.About free amino acids,L.sakei significantly degraded serine,arginine and aspartic acid,while S.proteamaculans and H.proteus significantly degraded serine and lysine.In addition,L.sakei had the strongest effect on promoting free fatty acid production,followed by S.proteamaculans and finally H.proteus.Evaluating from various indicators,the co-culture of the three strains did not have any effect.The key volatiles produced by L.sakei were 1-hexanol,acetic acid and hexanoic acid,S.proteamaculans produced 1-hexanol and acetoin,and H.proteus produced 1-hexanol,acetic acid and acetoin.In the end,1-hexanol,hexanoic acid and acetoin were proven to be spoilage markers for vacuum-packaged and chilled lamb.This study can provide fundamental information for inhibiting and rapid identification of spoilage in vacuum-packaged lamb.展开更多
A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embry...A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embryo sac formation. After the 3 megaspores at the micropylar end had degenerated, leaving only the chalazal megaspore in the nucellus, a nucellar cell adjacent to the megaspore differentiated into an aposporous initial, which later developed into a panicum_type embryo sac. It was an aposporous 4_nucleate embryo sac without chromosome reduction and composed of an egg, a single synergid and a central cell with 2 polar nuclei. The chalazal megaspore degenerated before the onset of the division in the aposporous initial cell.展开更多
The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China fr...The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China from June 2001 to early September 2002. The female flowers from previously bagged buds were treated respectively with paper bags, net bags and hand pollination by comparing with natural pollination. The results showed that female flowers treated with paper bags, net bags, hand pollination, and natural pollination all set fruits and seeds, but there was great difference in their fruit set, seed set, pre-emergent reproductive success (PERS) and seed germination rate for two populations. In both populations, PERS of hand pollination and natural pollination were higher than those of paper bagged and net bagged treatments. Among them, PERS of hand pollination was the highest, and PERS of net bagged treatment was the lowest. Both sexual reproduction and apomixis occurred simultaneously in W septentrionalis and seeds from both sexual and apomixis could germinate into seedlings. Therefore, the breeding system of W septentrionalis belonged to facultative apomixis. The apomixis in Magnoliaceae was reported for the first time.展开更多
The switch from C-3 to CAM pathway was induced by water stress in a C-3/CAM intermediate plant Sedum spectabile Boreau. Typical CAM criteria were observed upon 15 d of withholding water. Leaf delta(13)C value (-%) and...The switch from C-3 to CAM pathway was induced by water stress in a C-3/CAM intermediate plant Sedum spectabile Boreau. Typical CAM criteria were observed upon 15 d of withholding water. Leaf delta(13)C value (-%) and water content showed a linear correlation fashion. Chlorophyll fluorescence parameters and antioxidative capacity were altered by water stress. Phi(PSII) and q(P) were reduced by 50% and 34% of the control, respectively, while NPQ rose ca. 180%. SOD activity and ability to scavenge DPPH. free radical went down but membrane permeability changed slightly. However, when an additional photooxidation by MV with high PPFD was carried out with leaf discs from watered (C-3 mode) and drought plants (CAM mode), q(P) and Phi(PSII) in leaves at induced CAM mode stage continuously decreased to a very low level. High 1 - q(P) value (0.86) and 1 - q(P)/NPQ ratio (>1) indicated the presence of high reduction state and unbalance of light energy budget. Together with the marked loss of membrane integral, it was evidenced that photooxidative damage was more serious in the induced CAM mode than in the C-3 mode. No advantage of photooxidation tolerance was found at the induced CAM expression stage of the facultative CAM plant, as compared with its C-3 mode stage, and also with the constitutive CAM plants reported previously. The differences in photooxidation sensitivity between the inducible CAM expressing plant and the constitutive CAM plant were discussed.展开更多
Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited a...Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited attention has been paid to the composition and function of aerobic and facultative bacteria in this process. For analysis in this study, ten samples were collected from rust layers on steel plates that had been immersed in seawater for diff erent periods (i.e., six months and eight years) at Sanya and Xiamen, China. The cultivable aerobic bacterial community structure as well as the number of sulfate-reducing bacteria (SRB) were analyzed in both cases, while the proportion of facultative SRB among the isolated aerobic bacteria in each sample was also evaluated using a novel approach. Bacterial abundance results show that the proportions are related to sea location and immersion time;abundances of culturable aerobic bacteria (CAB) and SRB from Sanya were greater in most corrosion samples than those from Xiamen, and abundances of both bacterial groups were greater in samples immersed for six months than for eight years. A total of 213 isolates were obtained from all samples in terms of CAB community composition, and a phylogenetic analysis revealed that the taxa comprised four phyla and 31 genera. Bacterial species composition is related to marine location;the results show that Firmicutes and Proteobacteria were the dominant phyla, accounting for 98.13% of the total, while Bacillus and Vibrio were the dominant genera, accounting for 53.06% of the total. An additional sixfacultative SRB strains were also screened from the isolates obtained and were found to encompass the genus Vibrio (four strains), Staphylococcus (one strain), and Photobacterium (one strain). It is noteworthy that mentions of Photobacterium species have so far been absent from the literature, both in terms of its membership of the SRB group and its relationship to corrosion.展开更多
The effects of maternal salinity and light incubation on the salinity tolerance of the facultative halophyte Anabasis setifera during their germination stages were assessed. Seeds were collected from non-saline habita...The effects of maternal salinity and light incubation on the salinity tolerance of the facultative halophyte Anabasis setifera during their germination stages were assessed. Seeds were collected from non-saline habitats in Egypt and saline habitats in the United Arab Emirates （UAE）. The seeds of the two populations were germinated in 0, 100, 200, 400, 600 and 800 mM NaCI, and incubated at 25℃/15℃ in both 12-h light and 12-h darkness regimes and continuous darkness. Significantly more seeds germinated in the Egyptian population than in the UAE population. Salinity tolerance was significantly greater with the Egyptian population than with the UAE population, especially under the conditions of higher salinities. The difference in salinity tolerance between the seeds of two populations was attributed to their seed mass. In addition, germination was significantly faster for the Egyptian population than for the UAE population. Most of the saline treated seeds were able to recover their germination when transferred to distilled water, but this depended on their maternal salinity and light incubation. Recovery from higher salinities was significantly better for the seeds under darkness than for those under light in the UAE population, but the reverse was true for the seeds in the Egyptian population. The higher salinity tolerance for the A. setifera seeds from the non-saline Egyptian population and the lower salinity tolerance for the seeds from the saline UAE population cannot explain their natural distribution. Further studies about other possible roles, such as levels of different promoting and inhibiting phytohormones, are needed to understand the importance of salinity as an environmentally induced maternal effect.展开更多
Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating...Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating its tolerance to the metal.Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L-1 than at 25 mg L-1.The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation.Arsenic contents (mg g-1) in the fungus when exposed to 50 mg L-1 As (V) were measured as 11.1773,4.0983,and 8.0000 mg g-1 on day 3,6 and 9,respectively.The highest content was observed initially,i.e.on day 3,followed by a decline and a rise again.These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.展开更多
Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently be...Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.展开更多
Laboratory- scale experiments were conducted to determine new technology of waste sludge facultative metabolism . 10-L laboratory-scale facultative reactors were operated during 24-hour sludge residence time (SRT) and...Laboratory- scale experiments were conducted to determine new technology of waste sludge facultative metabolism . 10-L laboratory-scale facultative reactors were operated during 24-hour sludge residence time (SRT) and in room temperature . Results show that the organic matter in waste sludge after hydrolysis acidification will be reduced by 75.39%, the removal rate of CODer above 85% . Advantage of the process is hydrolysis-acidification in ambient air temperature as there is no need for facilities to be sealed or heated. In addition, the sludge will be recycled into the wastewater treatment system and finally towards zero-discharge.展开更多
Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that...Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that most of the strains were Bacillus genera, and six of the 29 strains were bigger than 10 mm of diameter of clear zones. For them, two strains were isolated from rumen fluid(L5 and L7) and other two were isolated from rumen residue(N5 and N9), while others were isolated from soil(T1) and diet(S6), respectively. Strains from rumen fluid and residue had higher activities of FPCase and CMCase, but lower β-glucosidases.展开更多
In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behav...In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behavior of the primary lagoon was evaluated, and the advantages and limitations of the three models were compared. For this purpose, 7-year operational data from the municipal WWTP were collected and processed;other necessary data—like dynamic temperature values— were estimated. A 2-year period was used for model calibration, while the remaining 5 years served as validation period. One of the models showed poor calibration fit values in the effluent concentration description (R2 of 0.242 and RMSE of 16.8 mg/L);however, with some modifications the adjust was enhanced (R2 of 0.409 and RMSE of 14.0 mg/L);a second model displayed a poor to moderate adjust (0.489 and 13.0 mg/L, respectively), and the third model achieved a moderate fit (0.528 and 11.9 mg/L), though it provided an overestimation of effluent concentration, especially in periods of heavy and frequent rain;this model with some adaptations the adjust was enhanced (R2 of 0.575 and RMSE of 11.4 mg/L). The validation fits are even lower, illustrating the inability of these models to properly describe the AFL behavior. The possible causes of the models’ inadequacy are discussed. Finally, it is established that in terms of AFL behavior description more research and model development are needed.展开更多
There exists a kind of symbiotic bacterium named ＂Candidatus Arsenophonus nilaparvatae＂ in the brown planthopper （BPH）, Nilaparvata lugens. After being filtered and assembled from the BPH genome sequencing project...There exists a kind of symbiotic bacterium named ＂Candidatus Arsenophonus nilaparvatae＂ in the brown planthopper （BPH）, Nilaparvata lugens. After being filtered and assembled from the BPH genome sequencing project, the genome sequence of this bacterial symbiont was obtained. After initial analysis based on the genome, we have found its potential role to synthesize B vitamins for the host. In order to better understand the lifestyle and the genomic changes of this symbiotic bacterium after the symbiotic relationship was established, we further report the characteristics of this draft genome. Compared with several other related bacteria, ＂Candidatus Arsenophonus nilaparvatae＂ has proven to be a facultative endosymbiont at the genomic level. Concurrently, the presence of fimbriae and flagella formation related genes indicates this maternally transmitted endosymbiont is most likely to retain the capacity to invade new hosts. Through further analysis of annotated gene sets, we also find evidence of genome reduction in its secretion system and metabolic pathways. These findings reflect its evolutionary trend to be an obligate one and enable a deeper study of microbe-insect interactions.展开更多
Facultative bacterial endosymbionts in insects have been under intense study during the last years. Endosymbionts can modify the insect＇s phenotype, conferring adap- tive advantages under environmental stress. This s...Facultative bacterial endosymbionts in insects have been under intense study during the last years. Endosymbionts can modify the insect＇s phenotype, conferring adap- tive advantages under environmental stress. This seems particularly relevant for a group of worldwide agricultural aphid pests, because endosymbionts modify key fitness-related traits, including host plant use, protection against natural enemies and heat tolerance. Aimed to understand the role of facultative endosymbionts on the success of introduced aphid pests, the distribution and abundance of 5 facultative endosymbionts （Hamiltonella defensa, Regiella insecticola, Serratia symbiotica, Rickettsia and Spiroplasma） were stud- ied and compared in 4 cereal aphids （Sitobion avenae, Diuraphis noxia, Metopolophium dirhodum and Schizaphis graminium） and in the pea aphid Acyrthosiphon pisum complex from 2 agroclimatic zones in Chile. Overall, infections with faeultative endosymbionts exhibited a highly variable and characteristic pattern depending on the aphid species/host race and geographic zone, which could explain the success of aphid pest populations after their introduction. While S. symbiotica and H. defensa were the most frequent endosym- bionts carried by the A. pisum pea-race and A. pisum alfalfa-race aphids, respectively, the most frequent facultative endosymbiont carried by all cereal aphids was R. insecticola. Interestingly, a highly variable composition of endosymbionts carried by S. avenae was also observed between agroclimatic zones, suggesting that endosymbionts are responding differentially to abiotic variables （temperature and precipitations）. In addition, our findings constitute the first report of bacterial endosymbionts in cereal aphid species not screened before, and also the first report of aphid endosymbionts in Chile.展开更多
A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken...A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken into account.A set of sufficient criteria for extinction(exponential extinction and extinction)and permanence(permanence in time average and stochastic permanence)of the system are established.Extensive simulation figures are demonstrated to support the theoretical findings.Meanwhile,we look at the effects of coupling white noises,impulses,intrinsic growth rates,intra-specific competition rates and inter-specific mutualism rates on the survival of populations.展开更多
Di-and tri-methylation of lysine 36 on histone H3(H3K36me2/3)is catalysed by histone methyltransferase Set2,which plays an essential role in transcriptional regulation.Although there is a single H3K36 methyltransferas...Di-and tri-methylation of lysine 36 on histone H3(H3K36me2/3)is catalysed by histone methyltransferase Set2,which plays an essential role in transcriptional regulation.Although there is a single H3K36 methyltransferase in yeast and higher eukaryotes,two H3K36 methyltransferases,Ash1 and Set2,were present in many filamentous fungi.However,their roles in H3K36 methylation and transcriptional regulation remained unclear.Combined with methods of RNA-seq and ChIP-seq,we revealed that both Ash1 and Set2 are redundantly required for the full H3K36me2/3 activity in Magnaporthe oryzae,which causes the devastating worldwide rice blast disease.Ash1 and Set2 distinguish genomic H3K36me2/3-marked regions and are differentially associated with repressed and activated transcription,respectively.Furthermore,Ash1-catalysed H3K36me2 was co-localized with H3K27me3 at the chromatin,and Ash1 was required for the enrichment and transcriptional silencing of H3K27me3-occupied genes.With the different roles of Ash1 and Set2,in H3K36me2/3 enrichment and transcriptional regulation on the stress-responsive genes,they differentially respond to various stresses in M.oryzae.Overall,we reveal a novel mechanism by which two H3K36 methyltransferases catalyze H3K36me2/3 that differentially associate with transcriptional activities and contribute to enrichment of facultative heterochromatin in eukaryotes.展开更多
The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we in...The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.展开更多
Previous research on social parasitism has largely ignored allodapine social parasites, which is surprising given the huge potential of these bees to provide a better understanding of social parasitism. Macrogalea ber...Previous research on social parasitism has largely ignored allodapine social parasites, which is surprising given the huge potential of these bees to provide a better understanding of social parasitism. Macrogalea berentyensis, a species that was previously suggested to be a social parasite, was collected in nests of M. ellioti, and also in nests consisting of only M. berentyensis. These f＇mdings, along with morphological and phylogenetic evidence, show that this species is a facultative social parasite. In the independently living M. berentyensis nests, brood were present that had been reared to an advanced stage, suggesting that： （i） these parasites may be effective at foraging and caring for their brood; or （ii） these nests may be colonies where all the hosts had died, and these parasites had yet to disperse. Macrogalea berentyensis is the closest relative of the facultative social parasite, M. antanosy, and both these species represent the most recent evolutionary origin of social parasitism within the allodapines. Further behavioral research on both these parasitic species would therefore have important implications for the understanding of the evolution of social parasitism.展开更多
Under conditions of increasing urbanization, the problem of studying the impact of synanthropic animal species on the functioning of urban ecosystems is becoming increasingly important. The purpose of this study was t...Under conditions of increasing urbanization, the problem of studying the impact of synanthropic animal species on the functioning of urban ecosystems is becoming increasingly important. The purpose of this study was to identify and analyze the species composition of synanthropic birds and mammals in the urban area of Osh (Kyrgyzstan), assess the degree of their bio-damaging activity, and develop recommendations to minimize their negative impact on various sectors of the urban environment. Field studies conducted in 2023–2024 revealed 22 species of synanthropic birds and 7 species of synanthropic mammals. Among birds, representatives of Columbiformes (3 species), Apodiformes (2 species), and Passeriformes (18 species) were identified, including families Hirundinidae, Motacillidae, Sturnidae, Corvidae, Turdidae, Paridae, Passeridae, Fringillidae, and Emberizidae. All recorded mammal species belonged to Rodentia, represented by the families Gliridae, Cricetidae, Gerbillidae, and Muridae. Most of these species are closely related to human activities, including obligate and facultative synanthropes (23 species) successfully adapted to anthropogenic landscapes. There are also pseudosynanthropes (6 species) that occur in populated areas but are not directly dependent on humans. The analysis showed that synanthropic species cause considerable damage to urban agriculture, infrastructure, and utilities. Major impacts include crop destruction, deterioration of monuments, damage to networks, and disease transmission. Special attention was paid to Meriones libycus, Ellobius tancrei, and Dryomys nitedula, recently identified as synanthropic species in Kyrgyz cities. Their inclusion provides new insights into urban ecosystem dynamics. The study proposes integrated control measures, including mechanical, chemical, and biological methods for effective management of bio-damaging species.展开更多
基金supported by the China Agriculture Research System of Ministry of Finance of the People’s Republic of China(MOF)Ministry of Agriculture+1 种基金Rural Affairs of the People’s Republic of China(MARA)(CARS-38)S&T Program of Hebei(215A7101D).
文摘Microbial growth causes lamb spoilage.This study explored the spoilage ability of Latilactobacillus sakei,Serratia proteamaculans and Hafnia proteus in vacuum-packed raw lamb,including growth ability,degradation of protein and lipid,and change of volatile organic compounds(VOCs)profile,meanwhile screened the key VOCs produced by the targeted strains with meat background excluding,finally confirmed the volatile spoilage marker of vacuum-packaged lamb by comparing with our previous work.The results showed that L.sakei,S.proteamaculans and H.proteus had excellent growth ability.L.sakei inoculated group significantly reduced the pH value,showed higher trichloroacetic acid-soluble peptides content,and excellently degraded sarcoplasmic and myofibrillar proteins.About free amino acids,L.sakei significantly degraded serine,arginine and aspartic acid,while S.proteamaculans and H.proteus significantly degraded serine and lysine.In addition,L.sakei had the strongest effect on promoting free fatty acid production,followed by S.proteamaculans and finally H.proteus.Evaluating from various indicators,the co-culture of the three strains did not have any effect.The key volatiles produced by L.sakei were 1-hexanol,acetic acid and hexanoic acid,S.proteamaculans produced 1-hexanol and acetoin,and H.proteus produced 1-hexanol,acetic acid and acetoin.In the end,1-hexanol,hexanoic acid and acetoin were proven to be spoilage markers for vacuum-packaged and chilled lamb.This study can provide fundamental information for inhibiting and rapid identification of spoilage in vacuum-packaged lamb.
文摘A cytological study on Apluda mutica L. revealed that this species was a facultative apomict with 60.74% of apomictic embryo sac formation. Its sexual reproduction exhibited the characteristics of polygonum_type embryo sac formation. After the 3 megaspores at the micropylar end had degenerated, leaving only the chalazal megaspore in the nucellus, a nucellar cell adjacent to the megaspore differentiated into an aposporous initial, which later developed into a panicum_type embryo sac. It was an aposporous 4_nucleate embryo sac without chromosome reduction and composed of an egg, a single synergid and a central cell with 2 polar nuclei. The chalazal megaspore degenerated before the onset of the division in the aposporous initial cell.
文摘The breeding system of an endangered dioecious species, Woonyoungia septentrionalis (Dandy) Law, was studied in two natural populations, the Mulun population and the Dahuangni population, in Guangxi Province, China from June 2001 to early September 2002. The female flowers from previously bagged buds were treated respectively with paper bags, net bags and hand pollination by comparing with natural pollination. The results showed that female flowers treated with paper bags, net bags, hand pollination, and natural pollination all set fruits and seeds, but there was great difference in their fruit set, seed set, pre-emergent reproductive success (PERS) and seed germination rate for two populations. In both populations, PERS of hand pollination and natural pollination were higher than those of paper bagged and net bagged treatments. Among them, PERS of hand pollination was the highest, and PERS of net bagged treatment was the lowest. Both sexual reproduction and apomixis occurred simultaneously in W septentrionalis and seeds from both sexual and apomixis could germinate into seedlings. Therefore, the breeding system of W septentrionalis belonged to facultative apomixis. The apomixis in Magnoliaceae was reported for the first time.
文摘The switch from C-3 to CAM pathway was induced by water stress in a C-3/CAM intermediate plant Sedum spectabile Boreau. Typical CAM criteria were observed upon 15 d of withholding water. Leaf delta(13)C value (-%) and water content showed a linear correlation fashion. Chlorophyll fluorescence parameters and antioxidative capacity were altered by water stress. Phi(PSII) and q(P) were reduced by 50% and 34% of the control, respectively, while NPQ rose ca. 180%. SOD activity and ability to scavenge DPPH. free radical went down but membrane permeability changed slightly. However, when an additional photooxidation by MV with high PPFD was carried out with leaf discs from watered (C-3 mode) and drought plants (CAM mode), q(P) and Phi(PSII) in leaves at induced CAM mode stage continuously decreased to a very low level. High 1 - q(P) value (0.86) and 1 - q(P)/NPQ ratio (>1) indicated the presence of high reduction state and unbalance of light energy budget. Together with the marked loss of membrane integral, it was evidenced that photooxidative damage was more serious in the induced CAM mode than in the C-3 mode. No advantage of photooxidation tolerance was found at the induced CAM expression stage of the facultative CAM plant, as compared with its C-3 mode stage, and also with the constitutive CAM plants reported previously. The differences in photooxidation sensitivity between the inducible CAM expressing plant and the constitutive CAM plant were discussed.
基金Supported by the National Basic Research Program of China(973 Program)(No.2014CB643304)the National Natural Science Foundation of China(No.41576080)the Key Research and Development Program of Shandong Province(No.2018GHY115003)
文摘Anaerobic, aerobic, and facultative bacteria are all present in corrosive environments. However, as previous studies to address corrosion in the marine environment have largely focused on anaerobic bacteria, limited attention has been paid to the composition and function of aerobic and facultative bacteria in this process. For analysis in this study, ten samples were collected from rust layers on steel plates that had been immersed in seawater for diff erent periods (i.e., six months and eight years) at Sanya and Xiamen, China. The cultivable aerobic bacterial community structure as well as the number of sulfate-reducing bacteria (SRB) were analyzed in both cases, while the proportion of facultative SRB among the isolated aerobic bacteria in each sample was also evaluated using a novel approach. Bacterial abundance results show that the proportions are related to sea location and immersion time;abundances of culturable aerobic bacteria (CAB) and SRB from Sanya were greater in most corrosion samples than those from Xiamen, and abundances of both bacterial groups were greater in samples immersed for six months than for eight years. A total of 213 isolates were obtained from all samples in terms of CAB community composition, and a phylogenetic analysis revealed that the taxa comprised four phyla and 31 genera. Bacterial species composition is related to marine location;the results show that Firmicutes and Proteobacteria were the dominant phyla, accounting for 98.13% of the total, while Bacillus and Vibrio were the dominant genera, accounting for 53.06% of the total. An additional sixfacultative SRB strains were also screened from the isolates obtained and were found to encompass the genus Vibrio (four strains), Staphylococcus (one strain), and Photobacterium (one strain). It is noteworthy that mentions of Photobacterium species have so far been absent from the literature, both in terms of its membership of the SRB group and its relationship to corrosion.
基金supported by the Qatar National Research Fund(5-260-1-053)
文摘The effects of maternal salinity and light incubation on the salinity tolerance of the facultative halophyte Anabasis setifera during their germination stages were assessed. Seeds were collected from non-saline habitats in Egypt and saline habitats in the United Arab Emirates （UAE）. The seeds of the two populations were germinated in 0, 100, 200, 400, 600 and 800 mM NaCI, and incubated at 25℃/15℃ in both 12-h light and 12-h darkness regimes and continuous darkness. Significantly more seeds germinated in the Egyptian population than in the UAE population. Salinity tolerance was significantly greater with the Egyptian population than with the UAE population, especially under the conditions of higher salinities. The difference in salinity tolerance between the seeds of two populations was attributed to their seed mass. In addition, germination was significantly faster for the Egyptian population than for the UAE population. Most of the saline treated seeds were able to recover their germination when transferred to distilled water, but this depended on their maternal salinity and light incubation. Recovery from higher salinities was significantly better for the seeds under darkness than for those under light in the UAE population, but the reverse was true for the seeds in the Egyptian population. The higher salinity tolerance for the A. setifera seeds from the non-saline Egyptian population and the lower salinity tolerance for the seeds from the saline UAE population cannot explain their natural distribution. Further studies about other possible roles, such as levels of different promoting and inhibiting phytohormones, are needed to understand the importance of salinity as an environmentally induced maternal effect.
基金due to the Department of Science and Technology,Government of India,for financial support sanctioned under SERC Fast Track Proposals for Young Scientists Scheme (No. SR/FT/L-99/2006) to AKV
文摘Tolerance of a facultative marine fungus Aspergillus flavus towards As (V) was tested.Luxuriant growth of the test isolate was observed in culture media with As (V) concentrations of 25 mg L-1 and 50 mg L-1,indicating its tolerance to the metal.Accumulation rate of arsenic was always higher when exposed to As (V) at 50 mg L-1 than at 25 mg L-1.The study reveals Aspergillus flavus as a promising candidate for environmental bioremediation.Arsenic contents (mg g-1) in the fungus when exposed to 50 mg L-1 As (V) were measured as 11.1773,4.0983,and 8.0000 mg g-1 on day 3,6 and 9,respectively.The highest content was observed initially,i.e.on day 3,followed by a decline and a rise again.These results provide baseline information for further explorations regarding the exploitation of the fungus for arsenic removal.
基金This project has been supported by the National Natural Science Foundation of China(grants 91853108,92153301,31771589,and 32170821 to K.Y,32101034 to F.C)Department of Science and Technology of Hunan Province(grants 2017RS3013,2017XK2011,2018DK2015,2019SK1012,and 2021JJ10054 to K.Y,and the innovative team program 2019RS1010)+2 种基金Central South University(2018CX032 to K.Y,2019zzts046 to Y.Z,2019zzts339 to X.L,2021zzts497 to H.Y,and the innovation-driven team project 2020CX016)D.M.F.v.A.is supported by Wellcome Trust Investigator Award(110061)a Novo Nordisk Foundation Laureate award(NNF21OC0065969).
文摘Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.
文摘Laboratory- scale experiments were conducted to determine new technology of waste sludge facultative metabolism . 10-L laboratory-scale facultative reactors were operated during 24-hour sludge residence time (SRT) and in room temperature . Results show that the organic matter in waste sludge after hydrolysis acidification will be reduced by 75.39%, the removal rate of CODer above 85% . Advantage of the process is hydrolysis-acidification in ambient air temperature as there is no need for facilities to be sealed or heated. In addition, the sludge will be recycled into the wastewater treatment system and finally towards zero-discharge.
基金Supported by Northeast Agricultural University Innovation Funding for Postgraduate(yjscx14007)China Agriculture Research System(CARS-37)
文摘Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that most of the strains were Bacillus genera, and six of the 29 strains were bigger than 10 mm of diameter of clear zones. For them, two strains were isolated from rumen fluid(L5 and L7) and other two were isolated from rumen residue(N5 and N9), while others were isolated from soil(T1) and diet(S6), respectively. Strains from rumen fluid and residue had higher activities of FPCase and CMCase, but lower β-glucosidases.
基金GrupoProagua SA de CV and its staff for the data supply and Consejo Nacional de Ciencia y Tecnologia(CONACYT)for Carlos Joel Abrego-Gongora’s scholarship(No.166201).
文摘In this research, three existing dynamic mathematical models for aerated lagoons were applied to an aerated facultative lagoon (AFL) plant for municipal wastewater treatment. The models’ ability to describe the behavior of the primary lagoon was evaluated, and the advantages and limitations of the three models were compared. For this purpose, 7-year operational data from the municipal WWTP were collected and processed;other necessary data—like dynamic temperature values— were estimated. A 2-year period was used for model calibration, while the remaining 5 years served as validation period. One of the models showed poor calibration fit values in the effluent concentration description (R2 of 0.242 and RMSE of 16.8 mg/L);however, with some modifications the adjust was enhanced (R2 of 0.409 and RMSE of 14.0 mg/L);a second model displayed a poor to moderate adjust (0.489 and 13.0 mg/L, respectively), and the third model achieved a moderate fit (0.528 and 11.9 mg/L), though it provided an overestimation of effluent concentration, especially in periods of heavy and frequent rain;this model with some adaptations the adjust was enhanced (R2 of 0.575 and RMSE of 11.4 mg/L). The validation fits are even lower, illustrating the inability of these models to properly describe the AFL behavior. The possible causes of the models’ inadequacy are discussed. Finally, it is established that in terms of AFL behavior description more research and model development are needed.
基金Acknowledgments This work was supported by grants from the National Natural Science Foundation of China （31272374 and 31070136） and the National Basic Research Program of China （973 Program, No. 2010CB 126205）.
文摘There exists a kind of symbiotic bacterium named ＂Candidatus Arsenophonus nilaparvatae＂ in the brown planthopper （BPH）, Nilaparvata lugens. After being filtered and assembled from the BPH genome sequencing project, the genome sequence of this bacterial symbiont was obtained. After initial analysis based on the genome, we have found its potential role to synthesize B vitamins for the host. In order to better understand the lifestyle and the genomic changes of this symbiotic bacterium after the symbiotic relationship was established, we further report the characteristics of this draft genome. Compared with several other related bacteria, ＂Candidatus Arsenophonus nilaparvatae＂ has proven to be a facultative endosymbiont at the genomic level. Concurrently, the presence of fimbriae and flagella formation related genes indicates this maternally transmitted endosymbiont is most likely to retain the capacity to invade new hosts. Through further analysis of annotated gene sets, we also find evidence of genome reduction in its secretion system and metabolic pathways. These findings reflect its evolutionary trend to be an obligate one and enable a deeper study of microbe-insect interactions.
文摘Facultative bacterial endosymbionts in insects have been under intense study during the last years. Endosymbionts can modify the insect＇s phenotype, conferring adap- tive advantages under environmental stress. This seems particularly relevant for a group of worldwide agricultural aphid pests, because endosymbionts modify key fitness-related traits, including host plant use, protection against natural enemies and heat tolerance. Aimed to understand the role of facultative endosymbionts on the success of introduced aphid pests, the distribution and abundance of 5 facultative endosymbionts （Hamiltonella defensa, Regiella insecticola, Serratia symbiotica, Rickettsia and Spiroplasma） were stud- ied and compared in 4 cereal aphids （Sitobion avenae, Diuraphis noxia, Metopolophium dirhodum and Schizaphis graminium） and in the pea aphid Acyrthosiphon pisum complex from 2 agroclimatic zones in Chile. Overall, infections with faeultative endosymbionts exhibited a highly variable and characteristic pattern depending on the aphid species/host race and geographic zone, which could explain the success of aphid pest populations after their introduction. While S. symbiotica and H. defensa were the most frequent endosym- bionts carried by the A. pisum pea-race and A. pisum alfalfa-race aphids, respectively, the most frequent facultative endosymbiont carried by all cereal aphids was R. insecticola. Interestingly, a highly variable composition of endosymbionts carried by S. avenae was also observed between agroclimatic zones, suggesting that endosymbionts are responding differentially to abiotic variables （temperature and precipitations）. In addition, our findings constitute the first report of bacterial endosymbionts in cereal aphid species not screened before, and also the first report of aphid endosymbionts in Chile.
文摘A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken into account.A set of sufficient criteria for extinction(exponential extinction and extinction)and permanence(permanence in time average and stochastic permanence)of the system are established.Extensive simulation figures are demonstrated to support the theoretical findings.Meanwhile,we look at the effects of coupling white noises,impulses,intrinsic growth rates,intra-specific competition rates and inter-specific mutualism rates on the survival of populations.
基金supported by the National Natural Science Foundation of China (32170192 and 32370200 to Z.T)National Youth Talent Support Program.
文摘Di-and tri-methylation of lysine 36 on histone H3(H3K36me2/3)is catalysed by histone methyltransferase Set2,which plays an essential role in transcriptional regulation.Although there is a single H3K36 methyltransferase in yeast and higher eukaryotes,two H3K36 methyltransferases,Ash1 and Set2,were present in many filamentous fungi.However,their roles in H3K36 methylation and transcriptional regulation remained unclear.Combined with methods of RNA-seq and ChIP-seq,we revealed that both Ash1 and Set2 are redundantly required for the full H3K36me2/3 activity in Magnaporthe oryzae,which causes the devastating worldwide rice blast disease.Ash1 and Set2 distinguish genomic H3K36me2/3-marked regions and are differentially associated with repressed and activated transcription,respectively.Furthermore,Ash1-catalysed H3K36me2 was co-localized with H3K27me3 at the chromatin,and Ash1 was required for the enrichment and transcriptional silencing of H3K27me3-occupied genes.With the different roles of Ash1 and Set2,in H3K36me2/3 enrichment and transcriptional regulation on the stress-responsive genes,they differentially respond to various stresses in M.oryzae.Overall,we reveal a novel mechanism by which two H3K36 methyltransferases catalyze H3K36me2/3 that differentially associate with transcriptional activities and contribute to enrichment of facultative heterochromatin in eukaryotes.
基金funded by the China Scholarship Council(grant number:201506300039)supported by the French Government through the "Investments for the Future" programs LABEX SIGNALIFE ANR-ll-LABX-0028-01 and IDEX UCAJedi ANR-15-IDEX-01.
文摘The pea aphid Acyrthosiphon pisum hosts different facultative symbionts(FS)which provide it with various benefits,such as tolerance to heat or protection against natural enemies(e.g.,fungi,parasitoid wasps).Here,we investigated whether and how the presence of certain FS could affect phenoloxidase(PO)activity,a key component of insect innate immunity,under normal and stressed conditions.For this,we used clones of A.pisum of difTerent genetic backgrounds(LLOl,YR2 and T3-8V1)lacking FS or harboring one or two(Regiella insecticola,Hamiltonella defensa,Serratia symbiotica Rickettsiella viridis).Gene expression and proteomics analyses of the aphid hemolymph indicated that the two A.pisum POs,PPOl and PP02,are expressed and translated into proteins.The level of PPO genes expression as well as the amount of PPO proteins and phenoloxidase activity in the hemolymph depended on both the aphid genotype and FS species.In particular,H.defensa and R.insecticola,but not S.symbiotica-h R.viridis,caused a sharp decrease in PO activity by interfering with both transcription and translation.The microinjection of different types of stressors(yeast,Escherichia coli,latex beads)in the YR2 lines hosting different symbionts affected the survival rate of aphids and,in most cases,also decreased the expression of PPO genes after 24 h.The amount and activity of PPO proteins varied according to the type of FS and stressor,without clear corresponding changes in gene expression.These data demonstrate that the presence of certain FS influences an important component of pea aphid immunity.
文摘Previous research on social parasitism has largely ignored allodapine social parasites, which is surprising given the huge potential of these bees to provide a better understanding of social parasitism. Macrogalea berentyensis, a species that was previously suggested to be a social parasite, was collected in nests of M. ellioti, and also in nests consisting of only M. berentyensis. These f＇mdings, along with morphological and phylogenetic evidence, show that this species is a facultative social parasite. In the independently living M. berentyensis nests, brood were present that had been reared to an advanced stage, suggesting that： （i） these parasites may be effective at foraging and caring for their brood; or （ii） these nests may be colonies where all the hosts had died, and these parasites had yet to disperse. Macrogalea berentyensis is the closest relative of the facultative social parasite, M. antanosy, and both these species represent the most recent evolutionary origin of social parasitism within the allodapines. Further behavioral research on both these parasitic species would therefore have important implications for the understanding of the evolution of social parasitism.
文摘Under conditions of increasing urbanization, the problem of studying the impact of synanthropic animal species on the functioning of urban ecosystems is becoming increasingly important. The purpose of this study was to identify and analyze the species composition of synanthropic birds and mammals in the urban area of Osh (Kyrgyzstan), assess the degree of their bio-damaging activity, and develop recommendations to minimize their negative impact on various sectors of the urban environment. Field studies conducted in 2023–2024 revealed 22 species of synanthropic birds and 7 species of synanthropic mammals. Among birds, representatives of Columbiformes (3 species), Apodiformes (2 species), and Passeriformes (18 species) were identified, including families Hirundinidae, Motacillidae, Sturnidae, Corvidae, Turdidae, Paridae, Passeridae, Fringillidae, and Emberizidae. All recorded mammal species belonged to Rodentia, represented by the families Gliridae, Cricetidae, Gerbillidae, and Muridae. Most of these species are closely related to human activities, including obligate and facultative synanthropes (23 species) successfully adapted to anthropogenic landscapes. There are also pseudosynanthropes (6 species) that occur in populated areas but are not directly dependent on humans. The analysis showed that synanthropic species cause considerable damage to urban agriculture, infrastructure, and utilities. Major impacts include crop destruction, deterioration of monuments, damage to networks, and disease transmission. Special attention was paid to Meriones libycus, Ellobius tancrei, and Dryomys nitedula, recently identified as synanthropic species in Kyrgyz cities. Their inclusion provides new insights into urban ecosystem dynamics. The study proposes integrated control measures, including mechanical, chemical, and biological methods for effective management of bio-damaging species.
