Baseline Assessment of Mesophotic Reefs of the Vitória-Trindade Seamount Chain Based on Water Quality,Microbial Diversity,Benthic Cover and Fish Biomass Data

Seamounts are considered important sources of biodiversity and minerals. However, their biodiversity and health status are not well understood; therefore, potential conservation problems are unknown. The mesophotic reefs of the Vitória-Trindade Seamount Chain (VTC) were investigated via benthic community and fish surveys, metagenomic and water chemistry analyses, and water microbial abundance estimations. The VTC is a mosaic of reef systems and includes fleshy algae dominated rhodolith beds, crustose coralline algae (CCA) reefs, and turf algae dominated rocky reefs of varying health levels. Macro-carnivores and larger fish presented higher biomass at the CCA reefs (4.4 kg per frame) than in the rhodolith beds and rocky reefs (0.0 to 0.1 kg per frame). A larger number of metagenomic sequences identified as primary producers (e.g., Chlorophyta and Streptophyta) were found at the CCA reefs. However, the rocky reefs contained more diseased corals (>90%) than the CCA reefs (~40%) and rhodolith beds (~10%). Metagenomic analyses indicated a heterotrophic and fast-growing microbiome in rocky reef corals that may possibly lead to unhealthy conditions possibly enhanced by environmental features (e.g. light stress and high loads of labile dissolved organic carbon). VTC mounts represent important hotspots of biodiversity that deserve further conservation actions.     

A single oral administration of acetic acid increased energy expenditure in C57BL/6J mice

We have reported that acetic acid (AcOH) intake suppresses body fat mass and up-regulates the genes involved in fatty acid oxidation, but it is not clear whether the suppression of body fat mass by AcOH administration is due to an increase in energy expenditure (EE). In this study, we investigated to determine whether a single oral administration of AcOH would increase EE in C57BL/6J mice treated with 1.5% AcOH. The AcOH treatment group had significantly higher oxygen consumption (VO(2)), EE, and fat oxidation (FAT) than the water treatment group. These results suggest that a single administration of AcOH increases EE, resulting in suppression of body fat mass.     

A rapid and non‐destructive screenable marker,FAST, for identifying transformed seeds of Arabidopsis thaliana

The creation of transgenic plants has contributed extensively to the advancement of plant science. Establishing homozygous transgenic lines is time‐consuming and laborious, and using antibiotics or herbicides to select transformed plants may adversely affect the growth of some transgenic plants. Here we describe a novel technology, which we have named FAST (fluorescence‐accumulating seed technology), that overcomes these difficulties. Although this technology was designed for use in Arabidopsis thaliana, it may be adapted for use in other plants. The technology is based on the expression of a fluorescent co‐dominant screenable marker FAST, under the control of a seed‐specific promoter, on the oil body membrane. The FAST marker harbors a fusion gene encoding either GFP or RFP with an oil body membrane protein that is prominent in seeds. The marker protein was only expressed in a specific organ (i.e. in dry seeds) and at a specific time (i.e. during dormancy), which are desirable features of selectable and/or screenable markers. This technique provides an immediate and non‐destructive method for identifying transformed dry seeds. It identified the heterozygous transformed seeds among the T₁ population and the homozygous seeds among the T₂ population with a false‐discovery rate of <1%. The FAST marker reduces the length of time required to produce homozygous transgenic lines from 7.5 to 4 months. Furthermore, it does not require sterilization, clean‐bench protocols or the handling of large numbers of plants. This technology should greatly facilitate the generation of transgenic Arabidopsis plants.     

Increased Resistance to Cd(II) in the Primitive Red Algae Cyanidioschyzon merolae

Growth of Cyanidioschyzon merolae was inhibited depending on the cadmium(II) concentration in the culture medium. Although a lower level (0.01 mM) of Cd(II) inhibited growth by a factor of 0.5, higher levels (0.1 and 1 mM) induced lag periods of 10–14 days. Algal cells pretreated with 1 mM Cd(II) for 27 days grew steadily in 1 mM Cd(II) without the lag period, demonstrating that the cells became Cd(II) resistant (CdR). Cells remained resistant after four cycles (7 days per cycle) of washing and re-growing in medium without Cd(II), while intracellular Cd(II) decreased to undetectable levels. These results suggest that the Cd(II)-resistant phenotype is heritable. This phenomena may be attributable to the presence of genetic inhomogeneity in the wild-type cell populations or to mutagenesis caused by Cd(II) stress. Intracellular Cd(II) levels significantly decreased in the CdR phenotype compared to the wild-type cells, indicating that resistant cells may have a defective gene that codes for Cd(II)-uptake protein or the ability to secrete Cd(II).     

Piwi expression in archeocytes and choanocytes in demosponges: insights into the stem cell system in demosponges

SUMMARY Little is known about the stem cells of organisms early in metazoan evolution. To characterize the stem cell system in demosponges, we identified Piwi homologs of a freshwater sponge, Ephydatia fluviatilis, as candidate stem cell (archeocyte) markers. EfPiwiA mRNA was expressed in cells with archeocyte cell morphological features. We demonstrated that these EfPiwiA‐expressing cells were indeed stem cells by showing their ability to proliferate, as indicated by BrdU‐incorporation, and to differentiate, as indicated by the coexpression of EfPiwiA with cell‐lineage‐specific genes in presumptive committed archeocytes. EfPiwiA mRNA expression was maintained in mature choanocytes forming chambers, in contrast to the transition of gene expression from EfPiwiA to cell‐lineage‐specific markers during archeocyte differentiation into other cell types. Choanocytes are food‐entrapping cells with morphological features similar to those of choanoflagellates (microvillus collar and a flagellum). Their known abilities to transform into archeocytes under specific circumstances and to give rise to gametes (mostly sperm) indicate that even when they are fully differentiated, choanocytes maintain pluripotent stem cell‐like potential. Based on the specific expression of EfPiwiA in archeocytes and choanocytes, combined with previous studies, we propose that both archeocytes and choanocytes are components of the demosponge stem cell system. We discuss the possibility that choanocytes might represent the ancestral stem cells, whereas archeocytes might represent stem cells that further evolved in ancestral multicellular organisms.     

Arabidopsis vacuolar sorting mutants (green fluorescent seed) can be identified efficiently by secretion of vacuole-targeted green fluorescent protein in their seeds

Two Arabidopsis thaliana genes have been shown to function in vacuolar sorting of seed storage proteins: a vacuolar sorting receptor, VSR1/ATELP1, and a retromer component, MAIGO1 (MAG1)/VPS29. Here, we show an efficient and simple method for isolating vacuolar sorting mutants of Arabidopsis. The method was based on two findings in this study. First, VSR1 functioned as a sorting receptor for beta-conglycinin by recognizing the vacuolar targeting signal. Second, when green fluorescent protein (GFP) fusion with the signal (GFP-CT24) was expressed in vsr1, mag1/vps29, and wild-type seeds, both vsr1and mag1/vps29 gave strongly fluorescent seeds but the wild type did not, suggesting that a defect in vacuolar sorting provided fluorescent seeds by the secretion of GFP-CT24 out of the cells. We mutagenized transformant seeds expressing GFP-CT24. From approximately 3,000,000 lines of M2 seeds, we obtained >100 fluorescent seeds and designated them green fluorescent seed (gfs) mutants. We report 10 gfs mutants, all of which caused missorting of storage proteins. We mapped gfs1 to VSR1, gfs2 to KAM2/GRV2, gfs10 to the At4g35870 gene encoding a novel membrane protein, and the others to different loci. This method should provide valuable insights into the complex molecular mechanisms underlying vacuolar sorting of storage proteins.     

Arabidopsis KAM2/GRV2 is required for proper endosome formation and functions in vacuolar sorting and determination of the embryo growth axis

We isolated an Arabidopsis thaliana mutant, katamari2 (kam2), that has a defect in the organization of endomembranes. This mutant had deformed endosomes and formed abnormally large aggregates with various organelles. Map-based cloning revealed that kam2 is allelic to gravitropism defective 2 (grv2). The KAM2/GRV2 gene encodes a homolog of a DnaJ domain-containing RECEPTOR-MEDIATED ENDOCYTOSIS-8, which is considered to play a vital role in the endocytotic pathway from the plasma membrane to lysosomes in animal cells. Immunofluorescent staining showed that KAM2/GRV2 protein localizes on punctate structures, which did not merge with any markers for Golgi, trans-Golgi network, endosomes, or prevacuolar compartments. KAM2/GRV2, which does not have a predicted transmembrane domain, was peripherally associated with the membrane surface of uncharacterized compartments. KAM2/GRV2 was expressed at the early to middle stages of seed maturation. We found kam2 mis-sorted seed storage proteins by secreting them from cells, indicating that KAM2/GRV2 is involved in the transport of the proteins into protein storage vacuoles. kam2 had another defect in embryogenesis. Half of the developing kam2-1 cotyledons grew into the opposite space of the seeds before the walking stick-shaped embryo stage. Our findings suggest that KAM2/GRV2 is required for proper formation of the endosomes involving protein trafficking to the vacuoles and determination of growth axis of the embryo.     

FABP7 expression in normal and stab-injured brain cortex and its role in astrocyte proliferation

Reactive gliosis, in which astrocytes as well as other types of glial cells undergo massive proliferation, is a common hallmark of all brain pathologies. Brain-type fatty acid-binding protein (FABP7) is abundantly expressed in neural stem cells and astrocytes of developing brain, suggesting its role in differentiation and/or proliferation of glial cells through regulation of lipid metabolism and/or signaling. However, the role of FABP7 in proliferation of glial cells during reactive gliosis is unknown. In this study, we examined the expression of FABP7 in mouse cortical stab injury model and also the phenotype of FABP7-KO mice in glial cell proliferation. Western blotting showed that FABP7 expression was increased significantly in the injured cortex compared with the contralateral side. By immunohistochemistry, FABP7 was localized to GFAP(+) astrocytes (21% of FABP7(+) cells) and NG2(+) oligodendrocyte progenitor cells (62%) in the normal cortex. In the injured cortex there was no change in the population of FABP7(+)/NG2(+) cells, while there was a significant increase in FABP7(+)/GFAP(+) cells. In the stab-injured cortex of FABP7-KO mice there was decrease in the total number of reactive astrocytes and in the number of BrdU(+) astrocytes compared with wild-type mice. Primary cultured astrocytes from FABP7-KO mice also showed a significant decrease in proliferation and omega-3 fatty acid incorporation compared with wild-type astrocytes. Overall, these data suggest that FABP7 is involved in the proliferation of astrocytes by controlling cellular fatty acid homeostasis.     

The second Phytophthora mating hormone defines interspecies biosynthetic crosstalk

The heterothallic species of the agricultural pest Phytophthora use mating hormones α1 and α2 to regulate their sexual reproduction. Here we describe the absolute stereostructure of the second mating hormone α2 as defined by spectroscopic analysis and total synthesis. We have uncovered not only the interspecies universality of α hormones but also the pathway by which α2 is biosynthesized from phytol by A2-mating type strains and metabolized to α1 by A1 strains.