Bacterial population in intestines of white shrimp,Litopenaeus vannamei fed a synbiotic containing Lactobacillus plantarum and galactooligosaccharide

The aims of this study were to unravel the intestinal microbiota of Litopenaeus vannamei after being fed a diet without (control) or with the synbiotic (SYN) for 60 days using next‐generation sequencing technology to see if changes in the intestinal microbiota were involved in the improved growth performance and health status of the shrimp. Next‐generation sequencing data showed that six phyla, 11 classes, 19 orders, 30 families, 58 genera and 73 species with taxonomic names assigned were detected. The majority of the operational taxonomic units (OTUs) was shared between the SYN and control shrimp and comprised 37 OTUs. However, intestinal biodiversity analyses revealed that SYN‐fed shrimp had a higher species richness, evenness and Shannon–Weaver index than did shrimp fed the control diet, but without reaching statistical significance. Interestingly, shrimp fed the SYN diet exhibited improved colonization of Lactobacillus plantarum and reduced prevalences of Vibrio harveyi and Photobacterium damselae in the intestines. These findings indicate that the SYN was able to modulate the intestinal bacterial community of shrimp and could be used to control vibriosis in shrimp.     

Heat Shock Protein 70 and Sex Steroid Receptors in the Follicular Structures of Induced Ovarian Cysts

The purpose of this study was to estimate the expression and relative amounts of estrogen (ER) and progesterone receptors (PR) and their isoforms as well as heat shock protein 70 (HSP70) in ovaries of rats with induced cystic ovarian disease (COD). Primary, secondary, tertiary, atretic and cystic follicles were evaluated by immunohistochemistry and total ovarian proteins were analyzed by Western blot. In the granulosa layer, growing and cystic follicles in the treated group have a higher expression of ERα than growing follicles of control individuals. In the theca interna layer, tertiary follicles presented a significantly higher expression of ERα in the treated group. An increase in total ERα protein was detected in the treated group. Granulosa cells of all growing, atretic and cystic follicles show a lower expression of ERβ in animals with COD, and the total protein expression of ERβ was lower in this group. The expression of PR was lower in the granulosa cell layer of tertiary and cystic follicles in treated animals, and theca interna layer had less intense immunostaining in this group. Although there were no differences in the expression of PR-B by Western blotting, the expression of PR-A was higher and the expression of PR-C was smaller in the treated group. An intense HSP70 immunostaining was observed in the cells of cystic follicles. By Western blotting, higher protein expression of HSP70 was detected in the ovarian samples of the control group than those of the treated ones. Ovaries of animals with COD exhibited an altered steroid receptor expression and subtype balance as compared with control animals, and an increase in HSP70 immunoexpression.     

Evidence of multiple divergent mitochondrial lineages within the southern African diplopod genus Bicoxidens Attems, 1928 (Spirostreptida)

Two recent studies have suggested that divergent mitochondrial lineages may be present within spirostreptid genera such as Bicoxidens Attems, 1928. Bicoxidens, similar to many other endemic soil invertebrates, exhibits low dispersal capabilities and strict microclimate habitat preferences, attributes that often lead to geographic isolation. Given that prolonged geographic isolation often lays the foundation for population genetic differentiation, genetic divergence and possibly speciation, there was good reason to suspect that Bicoxidens may consist of several distinct lineages. On this basis, the mitochondrial cytochrome c oxidase subunit 1 (COI) was used to reconstruct the phylogeny of Bicoxidens and reveal divergent lineages within the genus. Maximum likelihood and Bayesian inference analyses recovered a paraphyletic Bicoxidens phylogram with divergent lineages present in three species – B. friendi, B. flavicollis and B. brincki – suggesting high genetic diversity within the genus. Bayesian genetic cluster analyses suggested the presence of multiple distinct mitochondrial lineages within the genus with four identified in B. flavicollis alone. It was therefore concluded that the divergent lineages observed among Bicoxidens populations may suggest the presence of hidden species.     

竹集成材高频热压过程中板坯内温度的变化趋势

以毛竹Phyllostachys edulis集成材为研究对象,在不同条件下进行高频热压,通过对竹集成材板坯高频热压过程中芯层温度变化的统计分析,得到了竹集成材高频热压过程中板坯温度的变化规律。结果表明:在试验条件范围内,随着板坯含水率从6%增加到18%,涂胶量从200 g·m-2增加到300 g·m-2,板坯的温度明显升高。升温过程可以分为快速升温和慢速升温2个阶段。在快速升温阶段板坯内的温度随板坯初含水率、涂胶量及加热时间的提高而递增;在慢速升温阶段板坯初含水率及涂胶量对板坯内的温度的影响很小,板坯芯层升温速度随加热时间的增加而减少。通过试验数据分析,得出较优的高频热压胶合工艺条件为:涂胶量300 g·m-2,竹条含水率12%,高频热压时间7 min。     

Effects of Integrated Shrimp Farming in Vietnam

Despite being a leading shrimp exporter in the world market, shrimp farming in Vietnam is carried out by many small‐scale farmers who face constraints in complying with increasingly stringent food safety and sustainability standards. The best way for such small farmers to circumvent this paradox is to make effective integrations both horizontally and vertically. Using value chain and institutional economics approaches, this study determines the factors that influence the probability of horizontal and vertical integrations between the production and processing stages in the shrimp industry in Vietnam. Analysis results confirm that integrated shrimp aquaculture is much more effective than the traditionally small‐scale‐ and individual‐production mode. In addition, logit estimation results identify the key factors affecting integration, including effectiveness of the legal framework, production scale, infrastructure development, and farmers' skill and awareness. Several policy recommendations proposed to encourage the development of integration in shrimp farming in Vietnam could also be useful for other similar developing countries.     

Screening for plant transporter function by expressing a normalized Arabidopsis full-length cDNA library in Xenopus oocytes

Background  

We have developed a functional genomics approach based on expression cloning in Xenopus oocytes to identify plant transporter function. We utilized the full-length cDNA databases to generate a normalized library consisting of 239 full-length Arabidopsis thaliana transporter cDNAs. The genes were arranged into a 96-well format and optimized for expression in Xenopus oocytes by cloning each coding sequence into a Xenopus expression vector.     

Genetic characterization of chicken anemia viruses newly isolated from diseased chicks in Japan in 2020

In this study, a total of nine chicken samples obtained from two broiler flocks in Oita and Tottori prefectures in 2020 were examined for Chicken anemia virus (CAV) infection. The samples were collected from clinically suspected flocks and diseased chickens. The CAV genome was detected in all nine samples tested by real-time PCR. Phylogenetic analyses and sequence comparisons of the full-length VP1 gene sequences indicated that all the Japanese CAV strains obtained in this study formed a similar cluster of genotype III and shared high nucleotide (99.62–100%) identity. The current Japanese CAV strains were closely related to Chinese CAV strains but not related to vaccine strains. One positive selection site of VP1 was detected among the Japanese CAV strains.     

水杉苗期对氮素营养需求的研究

为研究水杉苗对氮素营养的需求 ,按 0 0 ,1 0 ,2 0 ,3 0 ,4 0和 5 0g氮 /盆 6个水平进行试验研究。结果表明 :水杉苗高、地径、分枝数、分枝总长等随着施氮量的增加而提高 ,但当施氮量超过 3 0 g/1 5kg土后 ,这些项目又随施氮量的继续增加而下降。水杉苗叶绿素的含量对氮素的反应亦与此类似 ;根、茎、叶的含氮量随施氮量的增加而增加。