Salinity-dependent copy number increase of a marine cyanobacterial endogenous plasmid

Listeria monocytogenes possessed glucose oxidase and NADH oxidase activities in whole cells and lysed protoplasts respectively. The NADH oxidase activity sedimented with the membrane fraction and was inhibited by the respiratory inhibitors rotenone, 2-heptyl-4-hydroxy-quinoline-N-oxide and cyanide, suggesting the presence of a membrane associated respiratory chain.     

Phylogenetic analysis of a novel sulfate-reducing magnetic bacterium, RS-1, demonstrates its membership of the δ-Proteobacteria

Abstract Most of the 16S ribosomal RNA gene of a sulfate-reducing magnetic bacterium, RS-1, was sequenced, and phylogenetic analysis was carried out. The results suggest that RS-1 is a member of the δ-Proteobacteria, and it appears to represent a new genus. RS-1 is the first bacterium reported outside the α-Proteobacteria that contains magnetite inclusions. RS-1 therefore disrupts the correlation between the α-Proteobacteria and possession of magnetite inclusions, and that between the δ-Proteobacteria and possession of greigite inclusions. The existence of RS-1 also suggests that intracellular magnetite biomineralization is of multiple evolutionary origins.     

Screening of marine cyanobacteria for high palmitoleic acid production

Abstract Screening of fatty acid composition in 150 strains of marine microalgae, cyanobacteria and green algae was carried out, and 20 strains showed relatively high contents of palmitoleic acid. Among them, two cyanobacteria, Phormidium sp. NKBG 041105 and Oscillatoria sp. NKBG 091600, showed an unusually high cis -palmitoleic acid content (54.5% and 54.4% of total fatty acid, respectively). Phormidium sp. NKBG 041105 had the highest cis -palmitoleic acid content per biomass (46.3 mg (g dry cell weight)⁻¹), and cis -palrnitoleic acid composition was found to be constant with varying temperature. These results indicate that this cyanobacterium could be considered as a new source for palmitoleic acid.     

Alteration of division polarity and preprophase band orientation in stomatogenesis by light

We have developed an experimental system in which the irradiation with a red light pulse induces stomatal disorientation in the hypocotyl epidermis ofCucumis sativus L. In this system, the orientation of the division plane in guard mother cells was not defined correctly. Preprophase bands formed in these cells but their orientation was abnormal.     

Pyrolysis of Cellulose

Comparative study of acetaldehyde, furfural and 5-hydroxymethyl furfural from celluloses which differed in crystallinity was made by pyrolytic gas chromatography.

Pyrolysis of tobacco cellulose at 200~300°C resulted in rapid increase in the yields of furfurals from the amorphous regions in comparison with that from the crystalline regions. At 500°C, however, acetaldehyde was obtained in higher yields from microcrystalline cellulose than that from tobacco cellulose under the same condition.

In thermogravimetric analysis, the threshold temperature for the pyrolysis of tobacco cellulose was lower than that of microcrystylline cellulose. These results showed that the yields of the volatile compounds from pyrolysis of cellulose depended on temperature and crystallinity.     

Microbody proliferation and segregation cycle in the single-microbody alga Cyanidioschyzon merolae

The proliferation cycle of the microbody was studied in the primitive red alga Cyanidioschyzon merolae, which contains one microbody per cell. Cells were synchronized with a dark/light cycle, and the morphology of the microbody and its interaction with other organelles were observed three-dimensionally by fluorescence microscopy, transmission electron microscopy, and computer-assisted three-dimensional reconstruction of serial thin sections. The microbody in interphase cells is a sphere of 0.3 μm in diameter without a core. In M-phase, the microbody passes through a series of irregular shapes, in the order rod, worm, branched, H-shaped and dumbbell, and symmetric fission occurs just before cytokinesis. The microbody duplicates its volume in M-phase and three-dimensional quantitative analysis revealed that its surface area increases before its volume does. The microbody touches the mitochondrion and the chloroplast throughout its proliferation cycle, except briefly in interphase cells, winding around the divisional plane of the mitochondrion at one phase. Immunocytochemical labeling of catalase as a marker of matrix proteins of the microbody revealed that the duplication of catalase occurs in tandem with the volume increase. While no specific apparatus was identified in the microbody divisional areas, we identified an electron-dense apparatus about 30–50 nm in diameter between the microbody and the mitochondrion that may play a role in segregating the daughter microbodies. These results are the first characterization to show the morphological changes of one microbody in a one-microbody alga without proliferation-inducing substrates, which have been used in many studies, and clearly show that two daughter microbodies arise by binary fission of the pre-existing microbody. Received: 11 November 1998 / Accepted: 22 December 1998     

Histological and Transcriptomic Analysis of Adult Japanese Medaka Sampled Onboard the International Space Station

To understand how humans adapt to the space environment, many experiments can be conducted on astronauts as they work aboard the Space Shuttle or the International Space Station (ISS). We also need animal experiments that can apply to human models and help prevent or solve the health issues we face in space travel. The Japanese medaka (Oryzias latipes) is a suitable model fish for studying space adaptation as evidenced by adults of the species having mated successfully in space during 15 days of flight during the second International Microgravity Laboratory mission in 1994. The eggs laid by the fish developed normally and hatched as juveniles in space. In 2012, another space experiment (“Medaka Osteoclast”) was conducted. Six-week-old male and female Japanese medaka (Cab strain osteoblast transgenic fish) were maintained in the Aquatic Habitat system for two months in the ISS. Fish of the same strain and age were used as the ground controls. Six fish were fixed with paraformaldehyde or kept in RNA stabilization reagent (n = 4) and dissected for tissue sampling after being returned to the ground, so that several principal investigators working on the project could share samples. Histology indicated no significant changes except in the ovary. However, the RNA-seq analysis of 5345 genes from six tissues revealed highly tissue-specific space responsiveness after a two-month stay in the ISS. Similar responsiveness was observed among the brain and eye, ovary and testis, and the liver and intestine. Among these six tissues, the intestine showed the highest space response with 10 genes categorized as oxidation–reduction processes (gene ontogeny term GO:0055114), and the expression levels of choriogenin precursor genes were suppressed in the ovary. Eleven genes including klf9, klf13, odc1, hsp70 and hif3a were upregulated in more than four of the tissues examined, thus suggesting common immunoregulatory and stress responses during space adaptation.     

From Reef to Table: Social and Ecological Factors Affecting Coral Reef Fisheries,Artisanal Seafood Supply Chains,and Seafood Security

Ocean and coastal ecosystems provide critical fisheries, coastal protection, and cultural benefits to communities worldwide, but these services are diminishing due to local and global threats. In response, place-based strategies involve communities and resource users in management have proliferated. Here, we present a transferable community-based approach to assess the social and ecological factors affecting resource sustainability and food security in a small-scale, coral reef fishery. Our results show that this small-scale fishery provides large-scale benefits to communities, including 7,353 ± 1547 kg yr^-1 (mean ± SE) of seafood per year, equating to >30,000 meals with an economic value of $78,432. The vast majority of the catch is used for subsistence, contributing to community food security: 58% is kept, 33.5% is given away, and 8.5% is sold. Our spatial analysis assesses the geographic distribution of community beneficiaries from the fishery (the “food shed” for the fishery), and we document that 20% of seafood procured from the fishery is used for sociocultural events that are important for social cohesion. This approach provides a method for assessing social, economic, and cultural values provided by small-scale food systems, as well as important contributions to food security, with significant implications for conservation and management. This interdisciplinary effort aims to demonstrate a transferable participatory research approach useful for resource-dependent communities as they cope with socioeconomic, cultural, and environmental change.     

The HIV-1 Gp120/CXCR4 Axis Promotes CCR7 Ligand-Dependent CD4 T Cell Migration: CCR7 Homo- and CCR7/CXCR4 Hetero-Oligomer Formation as a Possible Mechanism for Up-Regulation of Functional CCR7

During human immunodeficiency virus (HIV) infection, enhanced migration of infected cells to lymph nodes leads to efficient propagation of HIV-1. The selective chemokine receptors, including CXCR4 and CCR7, may play a role in this process, yet the viral factors regulating chemokine-dependent T cell migration remain relatively unclear. The functional cooperation between the CXCR4 ligand chemokine CXCL12 and the CCR7 ligand chemokines CCL19 and CCL21 enhances CCR7-dependent T cell motility in vitro as well as cell trafficking into the lymph nodes in vivo. In this study, we report that a recombinant form of a viral CXCR4 ligand, X4-tropic HIV-1 gp120, enhanced the CD4 T cell response to CCR7 ligands in a manner dependent on CXCR4 and CD4, and that this effect was recapitulated by HIV-1 virions. HIV-1 gp120 significantly enhanced CCR7-dependent CD4 T cell migration from the footpad of mice to the draining lymph nodes in in vivo transfer experiments. We also demonstrated that CXCR4 expression is required for stable CCR7 expression on the CD4 T cell surface, whereas CXCR4 signaling facilitated CCR7 ligand binding to the cell surface and increased the level of CCR7 homo- as well as CXCR4/CCR7 hetero-oligomers without affecting CCR7 expression levels. Our findings indicate that HIV-evoked CXCR4 signaling promotes CCR7-dependent CD4 T cell migration by up-regulating CCR7 function, which is likely to be induced by increased formation of CCR7 homo- and CXCR4/CCR7 hetero-oligomers on the surface of CD4 T cells.     

Pancreatic α-Amylase Controls Glucose Assimilation by Duodenal Retrieval through N-Glycan-specific Binding,Endocytosis, and Degradation

α-Amylase, a major pancreatic protein and starch hydrolase, is essential for energy acquisition. Mammalian pancreatic α-amylase binds specifically to glycoprotein N-glycans in the brush-border membrane to activate starch digestion, whereas it significantly inhibits glucose uptake by Na⁺/glucose cotransporter 1 (SGLT1) at high concentrations (Asanuma-Date, K., Hirano, Y., Le, N., Sano, K., Kawasaki, N., Hashii, N., Hiruta, Y., Nakayama, K., Umemura, M., Ishikawa, K., Sakagami, H., and Ogawa, H. (2012) Functional regulation of sugar assimilation by N-glycan-specific interaction of pancreatic α-amylase with glycoproteins of duodenal brush border membrane. J. Biol. Chem. 287, 23104–23118). However, how the inhibition is stopped was unknown. Here, we show a new mechanism for the regulation of intestinal glucose absorption. Immunohistochemistry revealed that α-amylase in the duodena of non-fasted, but not fasted, pigs was internalized from the pancreatic fluid and immunostained. We demonstrated that after N-glycan binding, pancreatic α-amylase underwent internalization into lysosomes in a process that was inhibited by α-mannoside. The internalized α-amylase was degraded, showing low enzymatic activity and molecular weight at the basolateral membrane. In a human intestinal Caco-2 cell line, Alexa Fluor 488-labeled pancreatic α-amylase bound to the cytomembrane was transported to lysosomes through the endocytic pathway and then disappeared, suggesting degradation. Our findings indicate that N-glycan recognition by α-amylase protects enterocytes against a sudden increase in glucose concentration and restores glucose uptake by gradual internalization, which homeostatically controls the postprandial blood glucose level. The internalization of α-amylase may also enhance the supply of amino acids required for the high turnover of small intestine epithelial cells. This study provides novel and significant insights into the control of blood sugar during the absorption stage in the intestine.