Turbid water induces refuge behaviour of a commercially important ayu: A field experiment for interstream movement using multiple artificial streams

Riverine systems are inherently dendritic in nature, and turbid water may not necessarily flow equally throughout an entire catchment. Tributaries have the potential to serve as refugia from temporarily turbid water in the main stem. As ayu (Plecoglossus altivelis) are one of the important species for the inland fisheries industry and recreational fishing, their behaviour in a branched river network is a primary concern. We released ayu with radio‐transmitting tags into two experimental streams that joined at a downstream pool. Turbid water was released into one of the streams, and we identified whether avoidance movement of ayu between the two experimental streams was triggered by flowing turbid water. The suspended solid concentration elevated rapidly after adding the turbid water and was maintained at more than 400 mg/L for 3 hr. Avoidance movement of ayu was triggered when the suspended solid concentration exceeded approximately 200 mg/L. Then, most ayu moved from the turbid stream to the nonturbid one, leading to a difference in ayu density between the two streams. Therefore, we demonstrated that turbid water induced interstream movement of a commercially important ayu as refuge behaviour, suggesting that river connectivity is important for the persistence of the ayu.     

The Effect of Methanolic Valeriana officinalis Root Extract on Adipocyte Differentiation and Adiponectin Production in 3T3-L1 Adipocytes

Plant Foods for Human Nutrition - Adipose tissue is an endocrine organ and its endocrine function is closely associated with type 2 diabetes mellitus. Valeriana officinalis (Valerian) exerts some...     

Molecular typing of sand fly species (Diptera, Psychodidae, Phlebotominae) from areas endemic for Leishmaniasis in Ecuador by PCR-RFLP of 18S ribosomal RNA gene

Surveillance of the distribution of sand fly species is important for prediction of the risk and expansion of Leishmania infection in endemic and surrounding areas. In the present study, a simple and reliable method of typing New World Lutzomyia species circulating in endemic areas in Ecuador was established by using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique. PCR-RFLP of 18S ribosomal RNA (rRNA) genes with the restriction enzyme AfaI and subsequently HinfI successfully identified seven sand fly species in nine endemic areas in Ecuador. Although intraspecific genetic-diversity affecting the RFLP-patterns was detected in a species, the patterns were species specific. The method promises to be a powerful tool for the classification of New World Lutzomyia species.     

Characterization of Aquimarina hainanensis isolated from diseased mud crab Scylla serrata larvae in a hatchery

Mass mortality due to necrosis signs occurred in hatchery-reared zoea stage larvae of the mud crab Scylla serrata in Okinawa, Japan, and a causative bacterium was isolated. In this study, we identified and characterized the bacterium by genome analysis, biochemical properties and pathogenicity. The bacterium was a Gram-negative, non-motile, long rod, forming yellow colonies on a marine agar plate. It grew at 20–33°C (not at 37°C) and degraded chitin and gelatin. Phylogenetic analysis of the 16S rRNA gene sequence identified the bacterium as Aquimarina hainanensis. Genome sequence data obtained from Illumina MiSeq generated 29 contigs with 3.56 Mbp in total length and a G + C content of 32.5%. The predicted 16 chitinase genes, as putative virulence factors, had certain homologies with those of genus Aquimarina. Experimental infection with the bacterium conducted on larvae of four crustacean species, brine shrimp Artemia franciscana, freshwater shrimp Caridina multidentata, swimming crab Portunus trituberculatus and mud crab S. serrata, revealed that this bacterium was highly virulent to these species. The present study suggests that the bacterium caused mass mortality in mud crab seed production was A. hainanensis and can be widely pathogenic to crustaceans.     

Analysis of Phytosterol,Fatty Acid,and Carotenoid Composition of 19 Microalgae and 6 Bivalve Species

ABSTRACT

In this study, the functional components of 19 microalgae and 6 bivalve species were investigated in the context of the application in bivalve feeding and human health food. Principal component analysis was performed to detect any association between the functional components and individual microalgal species or taxonomic group. The proportions of the functional components differed depending on the taxonomic group or species of microalga. The genera Cheatoceros, Thalassiosira, and Isochrysis contained high concentrations of fucosterol and fucoxanthin, which are present in large amounts in brown algae. Diatoms, haptophytes, and eustigmatophytes, which are used as feed for bivalves, were rich in fucosterol and eicosapentenoic acid (EPA); further, haptophytes were rich in docosahexaenoic acid (DHA). In addition, the microalgae associated with red tide, i.e., the raphidophytes, were found to be rich in fucoxanthin, β-sitosterol, and EPA, whereas dinoflagellates were rich in DHA. Seven bivalve species also contained high concentrations of fucosterol, EPA, and DHA, as did microalgae, which were used to feed by bivalves. These results are useful in selecting microalgae effectively as feed of the bivalves.     

Photoautotrophic cultivation of oleaginous microalgae and co-pelletization with filamentous fungi for cost-effective harvesting process and improved lipid yield

Oleaginous microalga Scenedesmus obliquus SIT06 was selected as potential biodiesel feedstocks due to its high lipid content and suitable fatty acid composition for production of biodiesel with high oxidative stability and high cetane number. The important factors for cultivating microalgae in photoautotrophic mode were optimized through response surface methodology (RSM). The highest microalgal biomass obtained was 1.99?±?0.12 g L^?1 with a high lipid content of 40.86?±?0.32%. To simplify harvesting process of microalgal cells, pellet-forming filamentous fungi were inoculated into the late log-phase of microalgae culture. Among the fungi tested, Cunninghamella echinulata TPU 4652 most effectively harvested the microalgal cells with the highest flocculation efficiency of 92.7%. Moreover, the biomass and lipids of microalgae-fungi pellets were as high as 4.45?±?0.06 and 1.21?±?0.08 g L^?1, respectively. The extracted lipids were mainly composed of C16:0, C18:0, and C18:1, and their estimated fuel properties meet with the international standards indicating their potential use as biodiesel feedstocks. This study has shown the strategies not only to simplify the harvesting process but also to increase the lipid yield and tailor the lipid composition.     

The locus for resistance to Asian soybean rust in PI 587855

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is one of the most serious soybean (Glycine max) diseases in tropical and subtropical areas. A soybean line, PI 587855, showed a resistance phenotype against ASR pathogens in Japan and South America at high frequency; however, little is known of the genetic control of this resistance and chromosomal location of the corresponding locus. Therefore, the aim of this study was to study the inheritance of PI 587855 resistance and map the corresponding locus with SSR markers aiming to use the linked markers in marker‐assisted selection. In the segregating population, resistance to ASR appeared to be controlled by a single dominant gene. The ASR resistance locus was mapped near to the chromosomal region where the resistant loci, Rpp1 and Rpp1‐b, were previously mapped. Comparative genetic mapping and disease reaction profiles of other seven lines carrying Rpp1 or Rpp1‐b to four Brazilian ASR isolates revealed that the resistance reaction exhibited by PI 587855 was similar to that of Rpp1‐b‐carrying varieties which have useful resistance to South American ASR strains.