查看更多>>摘要：Hypotrichs are one of the highly differentiated ciliated lineages which play important roles in ecological,environmental,evolutionary and basic biological studies.In the present study,we investigated the living characteristics,infraciliature,nuclear appa-ratus,ontogenesis and phylogenetic position of a marine hypotrichous ciliate,Apokeronopsis wrighti Long et al.,2008,which was isolated from coastal waters in Shenzhen,China.The new isolate resembles the type population in terms of morphological characte-ristics,morphometrics,and SSU rRNA gene sequence that is with a 99.7%similarity.Ontogenesis of A.wrighti is characterized by oral primordium for the proter as well as marginal and dorsal kineties anlagen in both filial products formed de novo,and the cirral row arranged along the paroral and endoral arises from several anterior frontoventral-transverse cirral streaks.Phylogenetic analyses based on SSU and concatenated gene data suggest that five species of Apokeronopsis form a monophyletic clade,and the genus Apo-keronopsis is closely related to Thigmokeronopsis and Metaurostylopsis.
查看更多>>摘要：The yellow-colored line of pearl oyster Pinctada fucata martensii displays a yellow prismatic layer and a white nacreous layer that can be used as an ideal model for research on shell color formation.Micro-Raman spectroscopy and transcriptome analyses were performed to explore the potential molecular mechanism underlying the phenotype differentiation.The micro-Raman spectros-copy results indicate that the prismatic layer exhibits distinct characteristic peaks of carotenoids,while these peaks are not prominent in the nacreous layer.In the transcriptome comparison of the central zone of mantle and mantle edge tissue,which function in nacre-ous and prismatic layer formation,respectively,935 significantly differentially expressed genes(DEGs)were identified,with 385 genes upregulated and 227 genes downregulated(|log2(Fold change)|>1 and false discovery rate<0.05)in the mantle edge tissue.Among these genes,some were associated with melanoma/melanogenesis,such as tyrosinase,zinc metalloprotease,glutathione S-transferase,and ATP-binding cassette sub-family;some were associated with the carotenoid-related pathway,including scavenger receptors,cytochrome P450 and lipoprotein receptor.Genes associated with porphyrin metabolism,including porphobilinogen deaminase,and copper/zinc superoxide dismutase,and genes associated with shell matrix protein,including amorphous calcium carbonate binding protein,shema-trin,PIF,and collagen,also exhibited significantly different expressions.It is speculated that the different colours between prismatic layer and nacreous layer in the yellow-colored line of P.f.martensii might be resulted from melanin,carotenoids and porphyrin me-tabolism,while genes related to shell structure and biomineralization might also affect coloration.Our results provide new insights to understand the mechanism of shell color formation in mollusca.
查看更多>>摘要：Stutzerimonas have been extensively studied due to their remarkable metabolic and physiological diversity.However,research on its phages is currently limited.In this study,we isolated a novel double-stranded DNA(dsDNA)phage,vB_SstM-PG1,from the marine environment that infects Stutzerimonas stutzeri G1.Its dsDNA genome is 37204 bp long with a G/C content of 64.14%and encodes 54 open reading frames.The phage possesses a tail packaging structure that is different from known Stutzerimonas stutzeri phages and exhibits structural protein characteristics similar to those of temperate phages.In addition,two genes of toxin-antitoxin system,including YdaS_antitoxin and HEPN_SAV_6107,were found in the vB_SstM-PG1 genome and play important roles in regu-lating host growth and metabolism.With phylogenetic tree and comparative genomic analysis,it has been determined that vB_SstM-PG1 is not closely related to any phages previously identified in the GenBank database.Instead,it has a connection with enigmatic,uncultured viruses.Specifically,the vB_SstM-PG1 virus exhibits an average nucleotide identity of over 70%with six uncultivated viruses identified in the IMG/VR v4 database.This significant finding has resulted in the identification of a novel viral genus known as Metabovirus.
查看更多>>摘要：The spatial and temporal distribution of bacterioplankton communities plays a vital role in understanding the ecological dynamics and health of aquatic ecosystems.In this study,we conducted a comprehensive investigation of the bacterioplankton com-munities in the Qiantang River(Hangzhou section).Water samples were collected quarterly from seven sites over a one-year period.Physical and chemical parameters,including dissolved oxygen(DO),water temperature(WT),chemical oxygen demand(COD),nitrite(NO2-),active phosphate(PO43-)and other indices were determined.In this study,the α diversity,β diversity and abundance differences of bacterial communities were investigated using 16S rRNA high-throughput sequencing analysis.The spatial and tem-poral distribution characteristics and main driving factors of the bacterioplankton community structure and diversity were discussed.The results showed that a total of 57 phyla were detected in the bacterioplankton community,among which Proteobacteria and Ac-tinomycetes were the two dominant groups with the highest relative abundance.The results of PCoA based on Bray-Curtis distance showed that the sampling season had a slightly greater effect on the changes in bacterioplankton community structure in the Qiantang River.Mantel and partial Mantel test showed that environmental variables(Mantel r=0.6739,P<0.0001;partial Mantel r=0.507,P=0.0001)were more important than geographical distance(Mantel r=0.5322,P<0.001;partial Mantel r=0.1563,P=0.001).The distance attenuation model showed that there was significant distance attenuation in all four seasons,and the maximum limit of bac-terial community diffusion was found in spring.RDA analysis showed that nine environmental factors,including COD,WT and DO,significantly affected community distribution(P<0.05).This study provides valuable insights into the spatial and temporal distribu-tion characteristics of bacterioplankton communities,shedding light on their ecological roles in the Qiantang River.The information obtained can guide future research on the interactions between bacterioplankton and their environment,enabling the development of effective conservation strategies and sustainable management practices for aquatic ecosystems.
查看更多>>摘要：To evaluate the combined effect of temperature and cadmium on the molecular responses of heat shock protein 70(hsp70)and P-glycoprotein(P-gp)in mantle,digestive gland and gills of Crassostrea gigas,oysters were exposed to combinations of five temperature levels(10,15,20,25,and 30℃)and 10 µg L-1 cadmium for 21 days.Oysters were sampled for mRNA quantification by qPCR,and the results showed that the P-gp gene expression changed significantly after treatment at different temperatures and dif-ferent treatment times.The P-gp gene expression was the highest in the digestive gland.Compared with the control group,the P-gp gene expression in cadmium treatment groups at all the different temperatures were significantly higher than the control group.The control oysters(kept at 10℃during the whole experiment without cadmium)expressed low levels of hsp70,but the groups treated with cadmium displayed somewhat higher levels.The present study demonstrated hsp70 and P-gp played an important role in the detoxification of Cd in C.gigas,and confirmed temperature should be considered for the assessment of Cd-induced toxicity in oys-ters.
查看更多>>摘要：As a renewable marine inorganic material,Coscinodiscus sp.has significant potential in the field of rapid hemostasis.However,the low yield of Coscinodiscus sp.seriously limits the application.In this study,two new culture modes were adopted to increase the production of Coscinodiscus sp.,the effect of changes in culture conditions and growth status on the hemostatic activity of diatoms was detected.To prevent Coscinodiscus sp.from sinking in culture,the suspension culture mode was realized by adding 0.5%agar.The semi-continuous high nutrient concentration culture mode increased the cell density of Coscinodiscus sp.to 11000 cells mL-1 and shorten the culture cycle to 5 d.In terms of coagulation activity,the addition of frustules reduced the in vitro coagula-tion time by half and the activation time of coagulation by 70%.The hemolysis rate and cytotoxicity of frustules harvested in the two culture modes did not change significantly.The results showed that suspension culture mode and high nutrient concentration culture mode only changed the growth state of Coscinodiscus sp.,while the hemostatic performance remained stable.
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