Vanadium Accumulation and Reduction by Vanadium-Accumulating Bacteria Isolated from the Intestinal Contents of Ciona robusta.

The sea squirt Ciona robusta (formerly Ciona intestinalis type A) has been the subject of many interdisciplinary studies. Known as a vanadium-rich ascidian, C. robusta is an ideal model for exploring microbes associated with the ascidian and the roles of these microbes in vanadium accumulation and reduction. In this study, we discovered two bacterial strains that accumulate large amounts of vanadium, CD2-88 and CD2-102, which belong to the genera Pseudoalteromonas and Vibrio, respectively. The growth medium composition impacted vanadium uptake. Furthermore, pH was also an important factor in the accumulation and localization of vanadium. Most of the vanadium(V) accumulated by these bacteria was converted to less toxic vanadium(IV). Our results provide insights into vanadium accumulation and reduction by bacteria isolated from the ascidian C. robusta to further study the relations between ascidians and microbes and their possible applications for bioremediation or biomineralization.

Mosquito-borne viruses, insect-specific flaviviruses (family Flaviviridae, genus Flavivirus), Banna virus (family Reoviridae, genus Seadornavirus), Bogor virus (unassigned member of family Permutotetraviridae), and alphamesoniviruses 2 and 3 (family Mesoniviridae, genus Alphamesonivirus) isolated from Indonesian mosquitoes.

Mosquitoes transmit many kinds of arboviruses (arthropod-borne viruses), and numerous arboviral diseases have become serious problems in Indonesia. In this study, we conducted surveillance of mosquito-borne viruses at several sites in Indonesia during 2016-2018 for risk assessment of arbovirus infection and analysis of virus biodiversity in mosquito populations. We collected 10,015 mosquitoes comprising at least 11 species from 4 genera. Major collected mosquito species were Culex quinquefasciatus, Aedes albopictus, Culex tritaeniorhynchus, Aedes aegypti, and Armigeres subalbatus. The collected mosquitoes were divided into 285 pools and used for virus isolation using two mammalian cell lines, Vero and BHK-21, and one mosquito cell line, C6/36. Seventy-two pools showed clear cytopathic effects only in C6/36 cells. Using RT-PCR and next-generation sequencing approaches, these isolates were identified as insect flaviviruses (family Flaviviridae, genus Flavivirus), Banna virus (family Reoviridae, genus Seadornavirus), new permutotetravirus (designed as Bogor virus) (family Permutotetraviridae, genus Alphapermutotetravirus), and alphamesoniviruses 2 and 3 (family Mesoniviridae, genus Alphamesonivirus). We believed that this large surveillance of mosquitoes and mosquito-borne viruses provides basic information for the prevention and control of emerging and re-emerging arboviral diseases.

Isolation, expression, and characterization of raw starch degrading α-amylase from a marine lake Bacillus megaterium NL3.

A land-locked marine lake Kakaban with its significant ecological paramaters provides a unique habitat for bacteria with novel biotechnology potential that uses a diverse array of catalytic agents, including α-amylase. Aiming at the isolation of raw starch degrading α-amylase from marine biodiversity, a gene encoding BmaN2 from a sea anemone associated bacterium Bacillus megaterium NL3 was cloned and expressed in Escherichia coli ArcticExpress (DE3). It comprises an open reading frame of 1,563 nucleotides encoding BmaN2 of 520 amino acids and belongs to the glycoside hydrolase family 13 subfamily 36 (GH13_36). This α-amylase has a maximum activity at pH 6.0 and 60 °C with a specific activity of 28.7 U mg-1. The BmaN2 activity is enhanced strongly by Ca2+ but inhibited by EDTA. BmaN2 also exhibits high catalytic efficiency on soluble starch with k cat /K M value of 14.1 mL mg-1 s-1. Despite no additional starch-binding domain, BmaN2 is able to hydrolyze various raw starches, such as wheat, corn, cassava, potato, rice, sago, and canna, in which granular wheat is the preferred substrate for BmaN2. These characteristics indicate that BmaN2 is a promising raw starch degrading enzyme within the subfamily GH13_36.