Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability t...Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability to prevent and treat peri-implantitis is hampered by a paucity of knowledge of how these biomes are acquired and the factors that engender normobiosis.Therefore,we combined a 3-month interventional study of 15 systemically and periodontally healthy adults with whole genome sequencing,finescale enumeration and graph theoretics to interrogate colonization dynamics in the pristine peri-implant sulcus.We discovered that colonization trajectories of implants differ substantially from adjoining teeth in acquisition of new members and development of functional synergies.Source-tracking algorithms revealed that this niche is initially seeded by bacteria trapped within the coverscrew chamber during implant placement.These pioneer species stably colonize the microbiome and exert a sustained influence on the ecosystem by serving as anchors of influential hubs and by providing functions that enable cell replication and biofilm maturation.Unlike the periodontal microbiome,recruitment of new members to the peri-implant community occurs on nepotistic principles.Maturation is accompanied by a progressive increase in anaerobiosis,however,the predominant functionalities are oxygen-dependent over the 12-weeks.The peri-implant community is easily perturbed following crown placement,but demonstrates remarkable resilience;returning to pre-perturbation states within three weeks.This study highlights important differences in the development of the periodontal and peri-implant ecosystems,and signposts the importance of placing implants in periodontally healthy individuals or following the successful resolution of periodontal disease.展开更多
1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this...1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.展开更多
Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduc...Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduction,its molecular mechanisms remain incompletely understood.This study investigated two grape transcription factors:EARLY BUD BREAK(VvEBB)and SHORT VEGETATIVE PHASE 4(VvSVP4).Through heterologous transformation in poplar,the research demonstrated that VvSVP4 functions as a negative regulator of bud break,while VvEBB serves as a positive regulator.Transcriptome analysis revealed significant enrichment of plant hormone signaling pathways particularly ABA,IAA,and CK in plants overexpressing VvSVP4(VvSVP4-OE)and VvEBB(VvEBB-OE)compared to controls.Endogenous hormone level changes correlated positively with transcriptome data.During endodormancy,VvSVP4 directly and positively regulated the ABA receptor gene Vv PYL9 expression,maintaining bud dormancy.Conversely,during ecodormancy,rapid upregulation of VvEBB negatively regulated the expression of sucrose nonfermenting 1-related protein kinase 2 gene(Vv SAPK2),facilitating dormancy release.This study provides comprehensive insights into how VvSVP4 and VvEBB genes regulate dormancy and bud break through cell cycle regulation and multiple hormone signaling pathways.展开更多
Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes...Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes the urgent need to comprehend tumor dormancy and its implications for cancer recurrence.Despite notable advancements,significant gaps remain in our understanding of the mechanisms underlying dormancy and the lack of reliable biomarkers for predicting relapse.This review provides a comprehensive analysis of the cellular,angiogenic,and immunological aspects of dormancy.It highlights the current therapeutic strategies targeting dormant cells,particularly combination therapies and immunotherapies,which hold promise in preventing relapse.By elucidating these mechanisms and proposing innovative research methodologies,this review aims to deepen our understanding of tumor dormancy,ultimately facilitating the development of more effective strategies for preventing cancer recurrence and improving patient outcomes.展开更多
Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are kno...Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are known to play crucial roles during seed dormancy and germination in P.koraiensis,it remains unclear whether these metabolic pathways function differentially across tissues.P.koraiensis seeds that had undergone different durations of moist chilling in their natural environment,yielding seeds with relatively deeper primary physiological dormancy(DDS)and seeds with released primary physiological dormancy(RDS).A non-targeted metabolomic analysis was conducted on the radicle and hypocotyl-cotyledon portions of both DDS and RDS,before and after a two-week incubation under favorable conditions.Under germination conditions,RDS and DDS showed divergent metabolic profiles,especially regarding carbohydrate metabolism.Specifically,RDS seeds showed significantly reduced substrates of respiratory metabolic pathways in both radicles and hypocotyl-cotyledons.Conversely,the intermediates of the carbohydrate metabolism pathway(particularly the tricarboxylic acid cycle)accumulating in radicles of DDS seeds under germination conditions.Moreover,in RDS,the carbohydrate metabolic pathways were more prevalent in the hypocotyl-cotyledon,while lysine degradation and ascorbate and aldarate metabolism were the dominant metabolic pathways in radicles.In contrast,the tricarboxylic acid cycle showed higher activity in DDS radicles compared to hypocotyl-cotyledons.We further demonstrated that carbohydratemetabolic pathways continue to play a dominant role in both dormancy maintenance and germination processes of P.koraiensis seeds.Notably,the carbohydratemetabolism in radicles likely exerts more critical regulatory functions in these two physiological processes compared to that in cotyledon and hypocotyl tissues.展开更多
Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism ...Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism remains elusive.Here,we report a direct link between colonization by arbuscular mycorrhizal fungi(AMF)and saline-alkali tolerance in maize.We identify s75,a natural maize mutant that cannot survive under moderate saline-alkali soil conditions or establish AM symbioses.The saline-alkali hypersensitive phenotype of s75 is caused by a 1340-bp deletion in Zm00001d033915,designated as ZmL75.This gene encodes a glycerol-3-phosphate acyltransferase localized in the endoplasmic reticulum,and is responsible for AMF colonization.ZmL75 expression levels in roots correspond with the root length colonization(RLC)rate during early vegetative development.Notably,the s75 mutant line shows a complete loss of AMF colonization,along with alterations in the diversity and structure of its root fungal microbiota.Conversely,overexpression of ZmL75 increases the RLC rate and enhances tolerance to saline-alkali soil conditions.These results suggest that ZmL75 is required for symbiosis with AMF,which directly improves saline-alkali tolerance.Our findings provide insights into maize-AMF interactions and offer a potential strategy for maize improvement.展开更多
In the early years of the 20th century,Britain sought to compete with Russia for dominance in East Asia,and set its sights on the strategic location of Xizang.Smallpox virus epidemics have been documented in Xizang si...In the early years of the 20th century,Britain sought to compete with Russia for dominance in East Asia,and set its sights on the strategic location of Xizang.Smallpox virus epidemics have been documented in Xizang since the 7th century,and smallpox remained a major public health issue in Xizang until the early 20th century.The British colonizers learned from their experience of passing on biological science and technology in India and carried out a series of medical activities in Xizang,the most influential of which was the smallpox vaccination for the people of Gyantse and other places.This paper examines the history of the fight against smallpox in Xizang from 1900 to 1907,and studies the historical process of British colonial expansion in Xizang,as well as the interaction between the Qing government and the British invaders in medical and healthcare events such as vaccination in Xizang.展开更多
[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were use...[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were used for soaking the seeds in the soil seed bank from different degraded grasslands,and the germination number of seeds was detected. [Result] When the seeds from soil seed bank were soaked with 60%,70%,80% and 90% H2SO4,the germination number of seeds was 0,indicating that the germination of seeds was inhibited; when the seeds were soaked with GA3,the germination number of seeds increased with the concentration of GA3 increasing. When the concentration of GA3 increased to 0.10%,the germination of seeds was inhibited; when the seeds were soaked with 0.2% KNO3,the germination number of seeds was greater than the blank control. [Conclusion] The number of remaining seeds was more in the soil seed banks collected from moderately degraded grassland and heavily degraded grassland; while the number of remaining seeds was small in the soil seed banks collected from lightly degraded grassland and extremely degraded grassland.展开更多
Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gno...Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.展开更多
[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean see...[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of （50.08-58.26 g）; among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.展开更多
Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in cons...Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in constant expanding and deepening. With the wide application of means of quantitative genetics method and mutant in the study on seed dormancy, a large number of quantitative trait loci（QTL） and mutant genes related with dormancy have been identified, which is of great significance for the further revelation of the detail mechanisms of plant seed dormancy and germination. This paper briefly introduced the genetic variation of seed dormancy in recent years, described the inductive formation of plant seed dormancy from the four aspects of dormancy specific gene, chromatin, seed growth development and hormone, and stated the action mechanism of environmental factors on seed dormancy from genetic and molecular levels, as well as the regulation and control mechanism of dormancy release, with the aim to provide certain references for the study on seed dormancy.展开更多
Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of s...Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica （L.） Willd. ex Del., Prosopis juliflora （Sw.） DC. ：and Dodonaea viscosa （L.） Jacq. The following treatments were applied： T1, untreated seed （control）; T2, sulphuric acid （97%） for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog （MS） medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable Seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds （80.8%-90.8%） and for scarified seeds of A. nilotica （50.2%） boiled in water. The germination indices, i.e., final germination percentage （FG）, mean daily germination （MDG） and germination rate （GR）, were significantly affected by treatments and species （p 〈 0.01）.展开更多
Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes ...Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most （413.8%）, followed by peroxidase （278.7%）, lipase （161.0%）, glucose-6-phosphate dehydrognase （149.1%） and amylase （60.6%） after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pal# urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.展开更多
Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the c...Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(DAR) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, DAR seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. DAR released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in two Rh. nobile populations; 76.92 and 83.33℃d, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.展开更多
Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria...Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.展开更多
Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we...Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments： sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid （GA3） application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germina- tion percentage （86.6%） was observed after five minutes scarification with sulfuric acid （75% v/v）, followed by 60 days of cold stratification. Duration of sulfuric acid scarification （5, 10, and 20 min） did not affect germination rates, but increasing duration of cold stratification （from 15 to 60 days）, increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.展开更多
Early colonization of intestinal microbiota during the neonatal stage plays an important role on the development of intestinal immune system and nutrients absorption of the host.Compared to the normal birth weight(NBW...Early colonization of intestinal microbiota during the neonatal stage plays an important role on the development of intestinal immune system and nutrients absorption of the host.Compared to the normal birth weight(NBW)piglets,intrauterine growth restricted(IUGR)piglets have a different intestinal microbiota during their early life,which is related to maternal imprinting on intestinal microbial succession during gestation,at birth and via suckling.Imbalanced allocation of limited nutrients among fetuses during gestation could be one of the main causes for impaired intestinal development and microbiota colonization in neonatal IUGR piglets.In this review,we summarized the potential impact of maternal imprinting on the colonization of the intestinal microbiota in IUGR piglets,including maternal undernutrition,imbalanced allocation of nutrients among fetuses,as well as vertical microbial transmission from mother to offspring during gestation and lactation.At the same time,we give information about the current maternal nutritional strategies(mainly breastfeeding,probiotics and prebiotics)to help colonization of the advantageous intestinal microbiota for IUGR piglets.展开更多
The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. n...The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. nectariana cv. Shuguang） and involved three treatments： a short day treatment （8 h）, a long day treatment （16 h）, and the normal condition as the control. The dormancy status was determined with the growth of shoot and the sprouting ability, and the respiratory rate was mensurated with oxygen electrode. Short day treatment could induce the growth stopping of peach shoots ahead, promote the development of dormancy, and induce buds into dormancy with 21 d previous to control. Long day treatment postponed the growth stopping and the induction and development of dormancy. The respiratory rate decreased according to the development of dormancy induction. The minimum respiratory rate appeared about 7 days after the start of dormancy induction. Bud respiratory rate increased during this period and then declined and remained at low level during dormancy period. Long day reduced buds respiratory rate slightly. Short day could induce dormancy obviously, and long day postponed dormancy induction. The changes of respiratory rate were correlated with the development of dormancy induction, and the bud respiratory rate was also affected by photoperiod.展开更多
In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used...In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used as materials. Different aged seeds( 0,3,6 and 9 d) of these four varieties were acquired by artificial accelerated aging method. Effects of artificial aging on malondialdehyde( MDA) content and catalase( CAT),ascorbate peroxidase( APX),peroxidase( POD) and superoxide dismutase( SOD) activity were investigated. The results showed that with the prolongation of aging time,MDA contents of these four rice varieties increased significantly,while the activity of antioxidant enzymes decreased dramatically. Besides,MDA contents and SOD,CAT and APX activity of the two inbred lines were significantly lower than those of the hybrid varieties. In addition,the activity of antioxidant enzymes in 4 K58 and C178 was significantly lower than that in 4 K59 and C179,respectively. This study indicated that artificial aging treatment significantly inhibited the activity of antioxidant system in seeds,improved membrane lipid peroxidation degree,and thus aggravated the deterioration of seeds. In addition,it also suggested that rice seeds with dormant property were more intolerant to storage.展开更多
To achieve a good production of a crop, it is essential to know the ability of the species to successfully complete two critical stages in the life cycle such as germination and seedling establishment. In this paper w...To achieve a good production of a crop, it is essential to know the ability of the species to successfully complete two critical stages in the life cycle such as germination and seedling establishment. In this paper we study in comparative form structure of the seed, the importance of tegument in dormancy, the effect of accelerated aging on seed germination and viability, and the early and late growth in J. curcas and J. macrocarpa. External morphology of the seeds allow difference and internally also the embryos show evident differences. J. macrocarpa germination is around 0% - 4%. The total removal of tegument showed a 50% increase and the other treatments between 0% - 10%. Aging accelerated by Tetrazolium test allowed a comparative analysis of VP and GP. J. curcas maintains both to 96 h, while J. macrocarpa the seed viability is registered along the all treatment. J. macrocarpa seeds have less synchronicity than those of J. curcas. ABA and JAs were detected in tegument of J. macrocarpa and J. curcas seeds. JA could have a roll in inhibition of germination of J. macrocarpa seeds. Early and late growth, FW and DW of root, hypocotyl, epicotyl and leaf of J. curcas were significantly different in both species.展开更多
基金supported by National Institutes of Health R03DE027492 to Shareef Dabdoubsupported by National Institutes of Health,project number 7R01DE027857-06supported by National Institutes of Health R56DE033913 awarded to Purnima Kumar.
文摘Dental implants have restored masticatory function to over 100000000 individuals,yet almost 1000000 implants fail each year due to peri-implantitis,a disease triggered by peri-implant microbial dysbiosis.Our ability to prevent and treat peri-implantitis is hampered by a paucity of knowledge of how these biomes are acquired and the factors that engender normobiosis.Therefore,we combined a 3-month interventional study of 15 systemically and periodontally healthy adults with whole genome sequencing,finescale enumeration and graph theoretics to interrogate colonization dynamics in the pristine peri-implant sulcus.We discovered that colonization trajectories of implants differ substantially from adjoining teeth in acquisition of new members and development of functional synergies.Source-tracking algorithms revealed that this niche is initially seeded by bacteria trapped within the coverscrew chamber during implant placement.These pioneer species stably colonize the microbiome and exert a sustained influence on the ecosystem by serving as anchors of influential hubs and by providing functions that enable cell replication and biofilm maturation.Unlike the periodontal microbiome,recruitment of new members to the peri-implant community occurs on nepotistic principles.Maturation is accompanied by a progressive increase in anaerobiosis,however,the predominant functionalities are oxygen-dependent over the 12-weeks.The peri-implant community is easily perturbed following crown placement,but demonstrates remarkable resilience;returning to pre-perturbation states within three weeks.This study highlights important differences in the development of the periodontal and peri-implant ecosystems,and signposts the importance of placing implants in periodontally healthy individuals or following the successful resolution of periodontal disease.
文摘1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.
基金supported by the China Agriculture Research System of MOF and MARA(CARS-29)the Xinjiang Uygur Autonomous Region Tianchi Talent Introduction Program,Chinathe Key R&D Technology Commissioner Projects in Hainan Province,China(ZDYF2024KJTPY008)。
文摘Bud dormancy represents a critical adaptation mechanism in perennial fruit plants,enabling survival during unfavorable environmental conditions.While this adaptive strategy is essential for plant survival and reproduction,its molecular mechanisms remain incompletely understood.This study investigated two grape transcription factors:EARLY BUD BREAK(VvEBB)and SHORT VEGETATIVE PHASE 4(VvSVP4).Through heterologous transformation in poplar,the research demonstrated that VvSVP4 functions as a negative regulator of bud break,while VvEBB serves as a positive regulator.Transcriptome analysis revealed significant enrichment of plant hormone signaling pathways particularly ABA,IAA,and CK in plants overexpressing VvSVP4(VvSVP4-OE)and VvEBB(VvEBB-OE)compared to controls.Endogenous hormone level changes correlated positively with transcriptome data.During endodormancy,VvSVP4 directly and positively regulated the ABA receptor gene Vv PYL9 expression,maintaining bud dormancy.Conversely,during ecodormancy,rapid upregulation of VvEBB negatively regulated the expression of sucrose nonfermenting 1-related protein kinase 2 gene(Vv SAPK2),facilitating dormancy release.This study provides comprehensive insights into how VvSVP4 and VvEBB genes regulate dormancy and bud break through cell cycle regulation and multiple hormone signaling pathways.
基金supported by the National Natural Sciences Foundation of China(82170974)the Central South University Research Program of Advanced Interdisciplinary Studies(2023QYJC038).
文摘Cancer recurrence,driven by the phenomenon of tumor dormancy,presents a formidable challenge in oncology.Dormant cancer cells have the ability to evade detection and treatment,leading to relapse.This review emphasizes the urgent need to comprehend tumor dormancy and its implications for cancer recurrence.Despite notable advancements,significant gaps remain in our understanding of the mechanisms underlying dormancy and the lack of reliable biomarkers for predicting relapse.This review provides a comprehensive analysis of the cellular,angiogenic,and immunological aspects of dormancy.It highlights the current therapeutic strategies targeting dormant cells,particularly combination therapies and immunotherapies,which hold promise in preventing relapse.By elucidating these mechanisms and proposing innovative research methodologies,this review aims to deepen our understanding of tumor dormancy,ultimately facilitating the development of more effective strategies for preventing cancer recurrence and improving patient outcomes.
基金supported by the National Natural Science Foundation of China(31901300).
文摘Pinus koraiensis is the dominant and constructive species of the zonal vegetation in Northeast China,known as the mixed broadleaf-Korean pine forest.Although carbohydrate metabolism pathways in the seed embryo are known to play crucial roles during seed dormancy and germination in P.koraiensis,it remains unclear whether these metabolic pathways function differentially across tissues.P.koraiensis seeds that had undergone different durations of moist chilling in their natural environment,yielding seeds with relatively deeper primary physiological dormancy(DDS)and seeds with released primary physiological dormancy(RDS).A non-targeted metabolomic analysis was conducted on the radicle and hypocotyl-cotyledon portions of both DDS and RDS,before and after a two-week incubation under favorable conditions.Under germination conditions,RDS and DDS showed divergent metabolic profiles,especially regarding carbohydrate metabolism.Specifically,RDS seeds showed significantly reduced substrates of respiratory metabolic pathways in both radicles and hypocotyl-cotyledons.Conversely,the intermediates of the carbohydrate metabolism pathway(particularly the tricarboxylic acid cycle)accumulating in radicles of DDS seeds under germination conditions.Moreover,in RDS,the carbohydrate metabolic pathways were more prevalent in the hypocotyl-cotyledon,while lysine degradation and ascorbate and aldarate metabolism were the dominant metabolic pathways in radicles.In contrast,the tricarboxylic acid cycle showed higher activity in DDS radicles compared to hypocotyl-cotyledons.We further demonstrated that carbohydratemetabolic pathways continue to play a dominant role in both dormancy maintenance and germination processes of P.koraiensis seeds.Notably,the carbohydratemetabolism in radicles likely exerts more critical regulatory functions in these two physiological processes compared to that in cotyledon and hypocotyl tissues.
基金National Natural Science Foundation of China(No.32171947 and No.31671699)which supported this research.
文摘Saline-alkali soil severely reduces the productivity of crops,including maize(Zea mays).Although several genes associated with saline-alkali tolerance have been identified in maize,the underlying regulatory mechanism remains elusive.Here,we report a direct link between colonization by arbuscular mycorrhizal fungi(AMF)and saline-alkali tolerance in maize.We identify s75,a natural maize mutant that cannot survive under moderate saline-alkali soil conditions or establish AM symbioses.The saline-alkali hypersensitive phenotype of s75 is caused by a 1340-bp deletion in Zm00001d033915,designated as ZmL75.This gene encodes a glycerol-3-phosphate acyltransferase localized in the endoplasmic reticulum,and is responsible for AMF colonization.ZmL75 expression levels in roots correspond with the root length colonization(RLC)rate during early vegetative development.Notably,the s75 mutant line shows a complete loss of AMF colonization,along with alterations in the diversity and structure of its root fungal microbiota.Conversely,overexpression of ZmL75 increases the RLC rate and enhances tolerance to saline-alkali soil conditions.These results suggest that ZmL75 is required for symbiosis with AMF,which directly improves saline-alkali tolerance.Our findings provide insights into maize-AMF interactions and offer a potential strategy for maize improvement.
文摘In the early years of the 20th century,Britain sought to compete with Russia for dominance in East Asia,and set its sights on the strategic location of Xizang.Smallpox virus epidemics have been documented in Xizang since the 7th century,and smallpox remained a major public health issue in Xizang until the early 20th century.The British colonizers learned from their experience of passing on biological science and technology in India and carried out a series of medical activities in Xizang,the most influential of which was the smallpox vaccination for the people of Gyantse and other places.This paper examines the history of the fight against smallpox in Xizang from 1900 to 1907,and studies the historical process of British colonial expansion in Xizang,as well as the interaction between the Qing government and the British invaders in medical and healthcare events such as vaccination in Xizang.
基金Supported by National Natural Science Foundation of China (30860061)National Science and Technology Support Program(2007BAC06B01)~~
文摘[Objective] The aim was to study the effect of different soak treatments on breaking seed dormancy in soil seed bank from different degraded grasslands. [Method] Different concentrations of H2SO4,GA3 and KNO3 were used for soaking the seeds in the soil seed bank from different degraded grasslands,and the germination number of seeds was detected. [Result] When the seeds from soil seed bank were soaked with 60%,70%,80% and 90% H2SO4,the germination number of seeds was 0,indicating that the germination of seeds was inhibited; when the seeds were soaked with GA3,the germination number of seeds increased with the concentration of GA3 increasing. When the concentration of GA3 increased to 0.10%,the germination of seeds was inhibited; when the seeds were soaked with 0.2% KNO3,the germination number of seeds was greater than the blank control. [Conclusion] The number of remaining seeds was more in the soil seed banks collected from moderately degraded grassland and heavily degraded grassland; while the number of remaining seeds was small in the soil seed banks collected from lightly degraded grassland and extremely degraded grassland.
文摘Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.
基金Supported by the"Twelfth Five-Year"Key Project for Crop Breeding of Sichuan Province(YZGG4-6)the Special Support Program for the Scientific Research Personnel of Sichuan Agricultural University~~
文摘[Objective] This study aimed to understand the characters of hard seeds of Amphicarpaea edgeworthii Benth. （Leguminosae） and explore the methods for break- ing dormancy. [Method] For both aerial and subterranean seeds of A. edgeworthii, the morphological characteristics were observed and the appropriate temperature for germination was explored. For aerial seeds of A. edgeworthii, the characters of hard seeds were studied, and concentrated sulfuric acid treatment, hot water soak treat- ment and mechanical damage treatment were compared to explore the methods for breaking seed dormancy. [Result] The aerial seeds were oblate and averaged 3.38 mm in length, 3.02 mm in width, 1.88 mm in thickness, 15.32 g in thousand grain weight, with a hard seed rate after of up to 98% natural maturation. The subter- ranean seeds were approximately oblate with a maximum diameter of 15 mm and a hundred grain weight of （50.08-58.26 g）; among all the treatments for breaking hardseededness, cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods, whereas hot water soak treatment was the least effective method; constant temperature between 20 and 30 ℃ was optimum for the germination of aerial seeds, and alternative temperature of 30/20 ℃ was most appropriate for the germination of subterranean seeds. [Conclusion] Cutting seed coat treatment and concentrated sulfuric acid treatment for 20 minutes were the most effective methods to break the hardseededness of A. edgeworthii.
基金Supported by the Natural Science Foundation for Youth of Qinghai Province(2015-ZJ-926Q)~~
文摘Dormancy is the biological adaptation behavior for seed, and it is regulated by many factors. A lot of studies have been done on various aspects of seed dormancy, and the breadth and width of these studies are in constant expanding and deepening. With the wide application of means of quantitative genetics method and mutant in the study on seed dormancy, a large number of quantitative trait loci（QTL） and mutant genes related with dormancy have been identified, which is of great significance for the further revelation of the detail mechanisms of plant seed dormancy and germination. This paper briefly introduced the genetic variation of seed dormancy in recent years, described the inductive formation of plant seed dormancy from the four aspects of dormancy specific gene, chromatin, seed growth development and hormone, and stated the action mechanism of environmental factors on seed dormancy from genetic and molecular levels, as well as the regulation and control mechanism of dormancy release, with the aim to provide certain references for the study on seed dormancy.
文摘Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless ,specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica （L.） Willd. ex Del., Prosopis juliflora （Sw.） DC. ：and Dodonaea viscosa （L.） Jacq. The following treatments were applied： T1, untreated seed （control）; T2, sulphuric acid （97%） for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog （MS） medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable Seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds （80.8%-90.8%） and for scarified seeds of A. nilotica （50.2%） boiled in water. The germination indices, i.e., final germination percentage （FG）, mean daily germination （MDG） and germination rate （GR）, were significantly affected by treatments and species （p 〈 0.01）.
基金This work is supported by the National Natural Science Foundation of China （Grant No. 30371156）in part by Grant sx （2003） 083 from the ＂Three Agriculture Engineering Program of Jiangsu Province＂.
文摘Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composition and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most （413.8%）, followed by peroxidase （278.7%）, lipase （161.0%）, glucose-6-phosphate dehydrognase （149.1%） and amylase （60.6%） after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pal# urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were depleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.
基金supported by National Key Research and Development Program of China (2017YFC0505201)NSFC (grant 31670206 to Z.-M. L. and 31570228 to B. S.),major Program of NSFC (grant 31590823 to H. S.)+1 种基金the Orientation Training Programme for Postdoctoral Fellows from Yunnan Province to D.-L. P.the Young Academic and Technical Leader Raising Foundation of Yunnan Province to B. S.
文摘Seed dormancy and germination characteristics are important factors determining plant reproductive success, and may be expected to have a major influence on plant distribution. In this study, we aimed to explore the characteristics of seed dormancy and germination in two endemic Rheum species(Rheum nobile and Rheum alexandrae) in the Himalaya-Hengduan Mountains. To determine the type of dormancy,fresh seeds of the two species(one population each) were incubated in light at 25/15 and 15/5℃, and then dry after-ripening(DAR) seeds were incubated on water agar substrate with or without GA_3. To determine the effect of temperature and light on germination, DAR seeds of the two species(two populations each) were incubated both in the light and in the dark at several temperatures, including constant and alternating temperatures. Base temperature(T_b) and thermal times for 50% germination(θ_(50)) were calculated. DAR released physiological dormancy(PD), increasing final germination at 15/5℃ and widening the range of germination temperatures from higher to lower, indicative of type 2 non-deep PD for the two Rheum species. Light had no significant effect on germination of seeds from the two species(two populations each). Seeds of the two species germinated significantly better(>80%) at medium temperatures(10-25℃) than at extreme low(5℃) or high(35℃) temperatures. Alternating temperatures(25/15 and 15/5℃) did not significantly increase the final germination of the two species either in the light and in the dark, but it promoted seed germination more quickly than corresponding constant temperatures in the light in both Rh. alexandrae populations, especially at 15/5℃. Germination in response to temperature was well described by the thermal-time model at suboptimal temperatures. The estimated Tbvalues were 1 and 0.9℃, respectively, in two Rh. nobile populations; 4 and 4.1℃,respectively, in two Rh. alexandrae populations; θ_(50)(thermal time) were 100 and 125℃d, respectively in two Rh. nobile populations; 76.92 and 83.33℃d, respectively in two Rh. alexandrae populations. The dormancy type, and germination responses to temperature and light condition does not explain why the two Rheum species are distributed in contrasting habitats. However, these findings reflect an advantageous germination strategy of these two Rheum species to adapt to the same alpine environments.
基金Supported by A post graduate student grant awarded by Irish Research Council for Science Engineering and Technology(To Dunne C)an award from the Health Research Board Ireland(To Dolan B)a grant from Science Foundation Ireland,No.08/SRC/B1393
文摘Helicobacter pylori(H.pylori)colonizes the stomach of humans and causes chronic infection.The majority of bacteria live in the mucus layer overlying the gastric epithelial cells and only a small proportion of bacteria are found interacting with the epithelial cells.The bacteria living in the gastric mucus may act as a reservoir of infection for the underlying cells which is essential for the development of disease.Colonization of gastric mucus is likely to be key to the establishment of chronic infection.How H.pylori manages to colonise and survive in the hostile environment of the human stomach and avoid removal by mucus flow and killing by gastric acid is the subject of this review.We also discuss how bacterial and host factors may together go some way to explaining the susceptibility to colonization and the outcome of infection in different individuals.H.pylori infection of the gastric mucosa has become a paradigm for chronic infection.Understanding of why H.pylori is such a successful pathogen may help us understand how other bacterial species colonise mucosal surfaces and cause disease.
文摘Mooseer （Allium hirtifolium Boiss.） is bulbous perennial herb widely used in pharmaceutical and food industry in Iran. We studied germination of mooseer seeds in two separate experiments. In the first experiment, we evaluated four treatments： sulfuric acid scarification, sandpaper scarification, cold stratification, and gibberellic acid （GA3） application. In the second experiment, we evaluated combinations of these treatments. All treatments in the first experiment had no effect on seed germination, suggesting that mooseer seeds have physical and physiological dormancy. In the second experiment, the highest germina- tion percentage （86.6%） was observed after five minutes scarification with sulfuric acid （75% v/v）, followed by 60 days of cold stratification. Duration of sulfuric acid scarification （5, 10, and 20 min） did not affect germination rates, but increasing duration of cold stratification （from 15 to 60 days）, increased germination from 28.3% to 86.6%. Our study showed that mooseer seeds have both physical and physiological dormancy.
基金supported by the Beijing Municipal Natural Science Foundation(S170001)the National Natural Science Foundation of China(31630074,31272449 and 31902170)+2 种基金the National Key Research and Development Program of China(2016YFD0500506 and 2018YDF0501002)the 111 Project(B16044)the Jinxinnong Animal Science Developmental Foundation.
文摘Early colonization of intestinal microbiota during the neonatal stage plays an important role on the development of intestinal immune system and nutrients absorption of the host.Compared to the normal birth weight(NBW)piglets,intrauterine growth restricted(IUGR)piglets have a different intestinal microbiota during their early life,which is related to maternal imprinting on intestinal microbial succession during gestation,at birth and via suckling.Imbalanced allocation of limited nutrients among fetuses during gestation could be one of the main causes for impaired intestinal development and microbiota colonization in neonatal IUGR piglets.In this review,we summarized the potential impact of maternal imprinting on the colonization of the intestinal microbiota in IUGR piglets,including maternal undernutrition,imbalanced allocation of nutrients among fetuses,as well as vertical microbial transmission from mother to offspring during gestation and lactation.At the same time,we give information about the current maternal nutritional strategies(mainly breastfeeding,probiotics and prebiotics)to help colonization of the advantageous intestinal microbiota for IUGR piglets.
基金the National 863 Program of China (2001AA247041)
文摘The responses of dormancy induction to illumination and the characteristics of respiratory rate were studied with the nectarine peach bud in this article. The trial was conducted with nectarine （Prunus persica var. nectariana cv. Shuguang） and involved three treatments： a short day treatment （8 h）, a long day treatment （16 h）, and the normal condition as the control. The dormancy status was determined with the growth of shoot and the sprouting ability, and the respiratory rate was mensurated with oxygen electrode. Short day treatment could induce the growth stopping of peach shoots ahead, promote the development of dormancy, and induce buds into dormancy with 21 d previous to control. Long day treatment postponed the growth stopping and the induction and development of dormancy. The respiratory rate decreased according to the development of dormancy induction. The minimum respiratory rate appeared about 7 days after the start of dormancy induction. Bud respiratory rate increased during this period and then declined and remained at low level during dormancy period. Long day reduced buds respiratory rate slightly. Short day could induce dormancy obviously, and long day postponed dormancy induction. The changes of respiratory rate were correlated with the development of dormancy induction, and the bud respiratory rate was also affected by photoperiod.
基金Supported by National Key Research and Development Project(2018YFD0101000)
文摘In this study,two indica varieties with different dormancy characteristics [4 K58( II-32 B dormant),4 K59( II-32 B) ] and their F2 seeds( C178,C179) obtained through hybridization with sterile line( II-32 A) were used as materials. Different aged seeds( 0,3,6 and 9 d) of these four varieties were acquired by artificial accelerated aging method. Effects of artificial aging on malondialdehyde( MDA) content and catalase( CAT),ascorbate peroxidase( APX),peroxidase( POD) and superoxide dismutase( SOD) activity were investigated. The results showed that with the prolongation of aging time,MDA contents of these four rice varieties increased significantly,while the activity of antioxidant enzymes decreased dramatically. Besides,MDA contents and SOD,CAT and APX activity of the two inbred lines were significantly lower than those of the hybrid varieties. In addition,the activity of antioxidant enzymes in 4 K58 and C178 was significantly lower than that in 4 K59 and C179,respectively. This study indicated that artificial aging treatment significantly inhibited the activity of antioxidant system in seeds,improved membrane lipid peroxidation degree,and thus aggravated the deterioration of seeds. In addition,it also suggested that rice seeds with dormant property were more intolerant to storage.
文摘To achieve a good production of a crop, it is essential to know the ability of the species to successfully complete two critical stages in the life cycle such as germination and seedling establishment. In this paper we study in comparative form structure of the seed, the importance of tegument in dormancy, the effect of accelerated aging on seed germination and viability, and the early and late growth in J. curcas and J. macrocarpa. External morphology of the seeds allow difference and internally also the embryos show evident differences. J. macrocarpa germination is around 0% - 4%. The total removal of tegument showed a 50% increase and the other treatments between 0% - 10%. Aging accelerated by Tetrazolium test allowed a comparative analysis of VP and GP. J. curcas maintains both to 96 h, while J. macrocarpa the seed viability is registered along the all treatment. J. macrocarpa seeds have less synchronicity than those of J. curcas. ABA and JAs were detected in tegument of J. macrocarpa and J. curcas seeds. JA could have a roll in inhibition of germination of J. macrocarpa seeds. Early and late growth, FW and DW of root, hypocotyl, epicotyl and leaf of J. curcas were significantly different in both species.
