Characterization and Expression Analysis of a Complement Component Gene in Sea Cucumber(Apostichopus japonicus)

The complement system plays a crucial role in the innate immune system of animals. It can be activated by distinct yet overlapping classical, alternative and lectin pathways. In the alternative pathway, complement factor B(Bf) serves as the catalytic subunit of complement component 3(C3) convertase, which plays the central role among three activation pathways. In this study, the Bf gene in sea cucumber(Apostichopus japonicus), termed Aj Bf, was obtained by rapid amplification of c DNA ends(RACE). The full-length c DNA of Aj Bf was 3231 bp in length barring the poly(A) tail. It contained an open reading frame(ORF) of 2742 bp encoding 913 amino acids, a 105 bp 5'-UTR(5'-terminal untranslated region) and a 384 bp 3'-UTR. Aj Bf was a mosaic protein with six CCP(complement control protein) domains, a VWA(von Willebrand factor A) domain, and a serine protease domain. The deduced molecular weight of Aj Bf protein was 101 k Da. Quantitative real time PCR(q RT-PCR) analysis indicated that the expression level of Aj Bf in A. japonicus was obviously higher at larval stage than that at embryonic stage. Expression detection in different tissues showed that Aj Bf expressed higher in coelomocytes than in other four tissues. In addation, Aj Bf expression in different tissues was induced significantly after LPS or Poly I:C challenge. These results indicated that Aj Bf plays an important role in immune responses to pathogen infection.

Development and Characterization of 35 SNP Markers in the Fat Greenling Hexagrammos otakii

Hexagrammos otakii is an important kind of economic fish species in East Asia. However, wild H. otakii resources have declined sharply in recent years as a result of human disturbance and habitat destruction. Thus, it is crucial to protect the current resources of H. otakii. In this study, 35 novel single nucleotide polymorphism (SNP) markers were developed based on restriction-site associated DNA sequencing. The results showed that the observed heterozygosity and expected heterozygosity ranged from 0.1875 to 0.6562 and 0.2679 to 0.5079, respectively. The minor allele frequency ranged from 0.1875 to 0.4375. Polymorphic information content ranged from 0.229 to 0.375. Six SNPs were found to be deviated significantly from the HWE (P H. otakii.

Health risk ranking of antibiotic resistance genes in the Yangtze River

Antibiotic resistance is an escalating global health concern,exacerbated by the pervasive presence of antibiotic resistance genes(ARGs)in natural environments.The Yangtze River,the world's third-longest river,traversing areas with intense human activities,presents a unique ecosystem for studying the impact of these genes on human health.Here,we explored ARGs in the Yangtze River,examining 204 samples from six distinct habitats of approximately 6000 km of the river,including free-living and particle-associated settings,surface and bottom sediments,and surface and bottom bank soils.Employing shotgun sequencing,we generated an average of 13.69 Gb reads per sample.Our findings revealed a significantly higher abundance and diversity of ARGs in water-borne bacteria compared to other habitats.A notable pattern of resistome coalescence was observed within similar habitat types.In addition,we developed a framework for ranking the risk of ARG and a corresponding method for calculating the risk index.Applying them,we identified water-borne bacteria as the highest contributors to health risks,and noted an increase in ARG risks in particle-associated bacteria correlating with heightened anthropogenic activities.Further analysis using a weighted ARG risk index pinpointed the ChengdueChongqing and Yangtze River Delta urban agglomerations as regions of elevated health risk.These insights provide a critical new perspective on ARG health risk assessment,highlighting the urgent need for strategies to mitigate the impact of ARGs on human health and to preserve the ecological and economic sustainability of the Yangtze River for future human use.