Potential interaction of brain natriuretic peptide with hyperadiponectinemia in preeclampsia

Adiponectin was reported recently to have roles in the pathophysiology of preeclampsia. Moreover, elevation of adiponectin and brain natriuretic peptide (BNP) has been observed in preeclampsia. We examined the possible links between adiponectin and BNP in the pathophysiology of preeclampsia. We performed a cross-sectional study in 56 preeclampsia patients and 56 controls matched for gestational age and body mass index. The BNP, leptin, and adiponectin levels were measured by ELISA, and their mRNA expressions were evaluated in omental adipose tissue by real-time PCR. The effects of BNP on adiponectin and leptin mRNA expression and secretion were investigated in primary cultures of adipocytes from obese and normal-weight women. The BNP, adiponectin, and leptin levels were significantly higher in preeclampsia patients compared with controls. The adiponectin level was increased significantly in normal-weight preeclampsia patients compared with overweight preeclampsia patients. Adiponectin mRNA expression was increased significantly in adipose tissues of preeclampsia patients compared with controls and was also increased significantly in normal-weight preeclampsia patients compared with overweight preeclampsia patients, whereas leptin was not. BNP and adiponectin showed significant positive correlations in both normal-weight and overweight preeclampsia patients. BNP had a significantly weaker effect on adiponectin in overweight compared with normal-weight preeclampsia patients. Moreover, BNP had a weaker effect on adiponectin production in adipocytes from overweight women compared with adipocytes from normal-weight women using primary culture of human adipocytes. These data suggested that BNP may play a role in hyperadiponectinemia of preeclampsia patients. The weaker effect of BNP on adiponectin production may participate in the pathophysiology of overweight preeclampsia patients.     

Differences in heat sensitivity between Japanese honeybees and hornets under high carbon dioxide and humidity conditions inside bee balls

Upon capture in a bee ball (i.e., a dense cluster of Japanese honeybees forms in response to a predatory attack), an Asian giant hornet causes a rapid increase in temperature, carbon dioxide (CO?), and humidity. Within five min after capture, the temperature reaches 46°C, and the CO? concentration reaches 4%. Relative humidity gradually rises to 90% or above in 3 to 4 min. The hornet dies within 10 min of its capture in the bee ball. To investigate the effect of temperature, CO?, and humidity on hornet mortality, we determined the lethal temperature of hornets exposed for 10 min to different humidity and CO?/O? (oxygen) levels. In expiratory air (3.7% CO?), the lethal temperature was ≥ 2° lower than that in normal air. The four hornet species used in this experiment died at 44-46°C under these conditions. Hornet death at low temperatures results from an increase in CO? level in bee balls. Japanese honeybees generate heat by intense respiration, as an overwintering strategy, which produces a high CO? and humidity environment and maintains a tighter bee ball. European honeybees are usually killed in the habitat of hornets. In contrast, Japanese honeybees kill hornets without sacrificing themselves by using heat and respiration by-products and forming tight bee balls.     

Occurrence of two closely related ricefishes, Javanese medaka (Oryzias javanicus) and Indian medaka (O. dancena) at sites with different salinity in Peninsular Malaysia

Among ricefishes of the genus Oryzias, the Javanese medaka (O. javanicus) and the Indian medaka (O. dancena) are highly adaptable to seawater. Although wide distribution of the two species in the brackish waters of South and South-East Asia has been reported, their habitat preference remains unknown. We surveyed 12 sites in five estuarial areas of the west coast of Peninsular Malaysia from Kuala Gula to Tanjung Piai. Both species were found in all five areas, suggesting their distribution throughout the west coast of Peninsular Malaysia. This is the southernmost-recorded appearance of O. dancena, to the best of our knowledge. However, the habitats of the two species were essentially separated: of the 12 surveyed sites, the species were found in co-existence at only two sites, and one or the other species was found alone at the remaining 10 sites. We compared temperature, salinity, pH, and dissolved oxygen (DO) at the sampling sites and found that the habitat of O. javanicus is with higher salinity and DO. The salinity and DO at the sites of co-existence are near the lowest values found at the O. javanicus-only sites, and the highest values at the O. dancena-only sites. These results suggest that O. javanicus and O. dancena habitats are essentially separated; the former prefers hyperosmotic conditions while the latter prefers hypoosmotic conditions, and the latter may be more tolerant of hypoxia. The two sites of co-existence are points of contact between the species’ separate distribution areas.     

Migration of Sakhalin taimen (<Emphasis Type="Italic">Parahucho perryi</Emphasis>): evidence of freshwater resident life history types

Sakhalin taimen (Parahucho perryi) range from the Russian Far East mainland along the Sea of Japan coast, and Sakhalin, Kuril, and Hokkaido Islands and are considered to primarily be an anadromous species. We used otolith strontium-to-calcium ratios (Sr/Ca) to determine the chronology of migration between freshwater and saltwater and identify migratory contingents of taimen collected from the Koppi River, Russia. In addition, we examined taimen from the Sarufutsu River, Japan and Tumnin River, Russia that were captured in marine waters. Transects of otolith Sr/Ca for the Sarufutsu River fish were consistent with patterns observed in anadromous salmonids. Two fish from the Tumnin River appeared to be recent migrants to saltwater and one fish was characterized by an otolith Sr/Ca transect consistent with marine migration. Using these transects as benchmarks, all Koppi River taimen were classified as freshwater residents. These findings suggest more work is needed to assess life history variability among locations and the role of freshwater productivity in controlling migratory behavior in taimen.     

Positive selection of Toll-like receptor 2 polymorphisms in two closely related old world monkey species, rhesus and Japanese macaques

Toll-like receptor 2 (TLR2) plays an important role in the recognition of a variety of pathogenic microbes. In the present study, we compared polymorphisms of TLR2 locus in two closely related old world monkey species, rhesus monkey (Macaca mulatta) and Japanese monkey (Macaca fuscata). By nucleotide sequencing of the third exon of TLR2 gene from 21 to 35 respective individuals, we could assign 17 haplotype combinations of 17 coding SNPs of ten non-synonymous and seven synonymous substitutions. A non-synonymous substitution at codon position 326 appeared to be differentially fixed in each species, asparagine for M. mulatta whereas tyrosine for M. fuscata, and may contribute to certain functional properties because it locates in the region contributing to ligand binding and interaction with dimerization partner of TLR2-TLR1 heterodimeric complex. Although TLR2 alleles have diverged to similar extent in both species, they have evolved in significantly different ways; TLR2 of M. fuscata has undergone purifying selection while the membrane-proximal part of the extracellular domain of M. mulatta TLR2 exhibits higher rates of non-synonymous substitutions, indicating a trace of Darwinian positive selection.     

Spatial distribution of viruses associated with planktonic and attached microbial communities in hydrothermal environments

Viruses play important roles in marine surface ecosystems, but little is known about viral ecology and virus-mediated processes in deep-sea hydrothermal microbial communities. In this study, we examined virus-like particle (VLP) abundances in planktonic and attached microbial communities, which occur in physical and chemical gradients in both deep and shallow submarine hydrothermal environments (mixing waters between hydrothermal fluids and ambient seawater and dense microbial communities attached to chimney surface areas or macrofaunal bodies and colonies). We found that viruses were widely distributed in a variety of hydrothermal microbial habitats, with the exception of the interior parts of hydrothermal chimney structures. The VLP abundance and VLP-to-prokaryote ratio (VPR) in the planktonic habitats increased as the ratio of hydrothermal fluid to mixing water increased. On the other hand, the VLP abundance in attached microbial communities was significantly and positively correlated with the whole prokaryotic abundance; however, the VPRs were always much lower than those for the surrounding hydrothermal waters. This is the first report to show VLP abundance in the attached microbial communities of submarine hydrothermal environments, which presented VPR values significantly lower than those in planktonic microbial communities reported before. These results suggested that viral lifestyles (e.g., lysogenic prevalence) and virus interactions with prokaryotes are significantly different among the planktonic and attached microbial communities that are developing in the submarine hydrothermal environments.     

Reduction of glucose uptake through inhibition of hexose transporters and enhancement of their endocytosis by methylglyoxal in Saccharomyces cerevisiae

Diabetes mellitus is characterized by an impairment of glucose uptake even though blood glucose levels are increased. Methylglyoxal is derived from glycolysis and has been implicated in the development of diabetes mellitus, because methylglyoxal levels in blood and tissues are higher in diabetic patients than in healthy individuals. However, it remains to be elucidated whether such factors are a cause, or consequence, of diabetes. Here, we show that methylglyoxal inhibits the activity of mammalian glucose transporters using recombinant Saccharomyces cerevisiae cells genetically lacking all hexose transporters but carrying cDNA for human GLUT1 or rat GLUT4. We found that methylglyoxal inhibits yeast hexose transporters also. Glucose uptake was reduced in a stepwise manner following treatment with methylglyoxal, i.e. a rapid reduction within 5 min, followed by a slow and gradual reduction. The rapid reduction was due to the inhibitory effect of methylglyoxal on hexose transporters, whereas the slow and gradual reduction seemed due to endocytosis, which leads to a decrease in the amount of hexose transporters on the plasma membrane. We found that Rsp5, a HECT-type ubiquitin ligase, is responsible for the ubiquitination of hexose transporters. Intriguingly, Plc1 (phospholipase C) negatively regulated the endocytosis of hexose transporters in an Rsp5-dependent manner, although the methylglyoxal-induced endocytosis of hexose transporters occurred irrespective of Plc1. Meanwhile, the internalization of hexose transporters following treatment with methylglyoxal was delayed in a mutant defective in protein kinase C.     

The fate of mycotoxins during the distillation process of barley shochu, a distilled alcoholic beverage

Mycotoxins are frequent contaminants of grains and critical risk substances for brewers. Fermented barley mash contaminated artificially with 13 representative mycotoxins was distilled with small-scale apparatuses to elucidate the possibility of mycotoxin transfer from mash to distillates. None of these were detected in the distillates. The distillation process can effectively reduce the contamination risk posed by mycotoxins in distilled alcoholic beverages.     

Effects of chitosan intake on fecal excretion of bisphenol A and di(2-ethyl)phthalate in rats

We evaluated the effects of chitosan intake on fecal excretion of bisphenol A (BPA) and di(2-ethyl)phthalate (DEHP) in rats. The rats were fed a chitosan diet (CHI group) or a control diet (control group) for 10 d and orally administrated BPA or DEHP (100, 500 mg/kg body weight, respectively) on day 4. Feces were collected and the rates of fecal excretion of BPA and DEHP were calculated. Fecal excretion rates of BPA and DEHP were significantly higher in the CHI group than in the control group. A significant negative correlation was observed between the fecal excretion rates of BPA and DEHP and apparent fat digestibility. Furthermore, the CHI group showed not only increased but also accelerated BPA excretion into the feces. In conclusion, we found that that chitosan intake significantly increased the fecal excretion of BPA, DEHP, and fat, suggesting that it might be useful for reducing adverse effects caused by lipophilic xenobiotics.