Evaluation of major membrane protein-II as a tool for serodiagnosis of leprosy

As serodiagnosis is the easiest way of diagnosing a disease, the utility of Mycobacterium leprae-derived major membrane protein-II (MMP-II), one of the immuno-dominant antigens, in the serodiagnosis of leprosy was examined. The percent positivity by an enzyme-linked immunosorbent assay for anti-MMP-II antibody was 82.4% for multi-bacillary leprosy, and the specificity of the test was 90.1%. For pauci-bacillary leprosy where cell-mediated immunity predominates, 39.0% showed positive results. These percentage values were significantly higher than these values obtained for existing phenolic glycolipid-I based methods, suggesting that MMP-II antibody detection would facilitate the diagnosis of leprosy.     

Dissimilatory Iodate Reduction by Marine Pseudomonas sp. Strain SCT

Bacterial iodate (IO₃⁻) reduction is poorly understood largely due to the limited number of available isolates as well as the paucity of information about key enzymes involved in the reaction. In this study, an iodate-reducing bacterium, designated strain SCT, was newly isolated from marine sediment slurry. SCT is phylogenetically closely related to the denitrifying bacterium Pseudomonas stutzeri and reduced 200 μM iodate to iodide (I⁻) within 12 h in an anaerobic culture containing 10 mM nitrate. The strain did not reduce iodate under the aerobic conditions. An anaerobic washed cell suspension of SCT reduced iodate when the cells were pregrown anaerobically with 10 mM nitrate and 200 μM iodate. However, cells pregrown without iodate did not reduce it. The cells in the former category showed methyl viologen-dependent iodate reductase activity (0.31 U mg⁻¹), which was located predominantly in the periplasmic space. Furthermore, SCT was capable of anaerobic growth with 3 mM iodate as the sole electron acceptor, and the cells showed enhanced activity with respect to iodate reductase (2.46 U mg⁻¹). These results suggest that SCT is a dissimilatory iodate-reducing bacterium and that its iodate reductase is induced by iodate under anaerobic growth conditions.     

Endothelial-to-mesenchymal transition contributes to cardiac fibrosis

Cardiac fibrosis, associated with a decreased extent of microvasculature and with disruption of normal myocardial structures, results from excessive deposition of extracellular matrix, which is mediated by the recruitment of fibroblasts. The source of these fibroblasts is unclear and specific anti-fibrotic therapies are not currently available. Here we show that cardiac fibrosis is associated with the emergence of fibroblasts originating from endothelial cells, suggesting an endothelial-mesenchymal transition (EndMT) similar to events that occur during formation of the atrioventricular cushion in the embryonic heart. Transforming growth factor-beta1 (TGF-beta1) induced endothelial cells to undergo EndMT, whereas bone morphogenic protein 7 (BMP-7) preserved the endothelial phenotype. The systemic administration of recombinant human BMP-7 (rhBMP-7) significantly inhibited EndMT and the progression of cardiac fibrosis in mouse models of pressure overload and chronic allograft rejection. Our findings show that EndMT contributes to the progression of cardiac fibrosis and that rhBMP-7 can be used to inhibit EndMT and to intervene in the progression of chronic heart disease associated with fibrosis.     

Genetic mapping of the rice resistance-breaking gene of the brown planthopper Nilaparvata lugens

Host plant resistance has been widely used for controlling the major rice pest brown planthopper (BPH, Nilaparvata lugens). However, adaptation of the wild BPH population to resistance limits the effective use of resistant rice varieties. Quantitative trait locus (QTL) analysis was conducted to identify resistance-breaking genes against the anti-feeding mechanism mediated by the rice resistance gene Bph1. QTL analysis in iso-female BPH lines with single-nucleotide polymorphism (SNP) markers detected a single region on the 10th linkage group responsible for the virulence. The QTL explained from 57 to 84% of the total phenotypic variation. Bulked segregant analysis with next-generation sequencing in F₂ progenies identified five SNPs genetically linked to the virulence. These analyses showed that virulence to Bph1 was controlled by a single recessive gene. In contrast to previous studies, the gene-for-gene relationship between the major resistance gene Bph1 and virulence gene of BPH was confirmed. Identified markers are available for map-based cloning of the major gene controlling BPH virulence to rice resistance.     

Chemical Discrimination and Aggressiveness via Cuticular Hydrocarbons in a Supercolony-Forming Ant,Formica yessensis

Background

Territorial boundaries between conspecific social insect colonies are maintained through nestmate recognition systems. However, in supercolony-forming ants, which have developed an extraordinary social organization style known as unicoloniality, a single supercolony extends across large geographic distance. The underlying mechanism is considered to involve less frequent occurrence of intraspecific aggressive behaviors, while maintaining interspecific competition. Thus, we examined whether the supercolony-forming species, Formica yessensis has a nestmate recognition system similar to that of the multicolonial species, Camponotus japonicus with respect to the cuticular hydrocarbon-sensitive sensillum (CHC sensillum), which responds only to non-nestmate CHCs. We further investigated whether the sensory system reflects on the apparent reduced aggression between non-nestmates typical to unicolonial species.

Methodology/Principal Findings

F. yessensis constructs supercolonies comprising numerous nests and constitutes the largest supercolonies in Japan. We compared the within-colony or between-colonies’ (1) similarity in CHC profiles, the nestmate recognition cues, (2) levels of the CHC sensillar response, (3) levels of aggression between workers, as correlated with geographic distances between nests, and (4) their genetic relatedness. Workers from nests within the supercolony revealed a greater similarity of CHC profiles compared to workers from colonies outside it. Total response of the active CHC sensilla stimulated with conspecific alien CHCs did not increase as much as in case of C. japonicus, suggesting that discrimination of conspecific workers at the peripheral system is limited. It was particularly limited among workers within a supercolony, but was fully expressed for allospecific workers.

Conclusions/Significance

We demonstrate that chemical discrimination between nestmates and non-nestmates in F. yessensis was not clear cut, probably because this species has only subtle intraspecific differences in the CHC pattern that typify within a supercolony. Such an incomplete chemical discrimination via the CHC sensilla is thus an important factor contributing to decreased occurrence of intraspecific aggressive behavior especially within a supercolony.     

Combination treatment of rosuvastatin or atorvastatin, with regular exercise improves arterial wall stiffness in patients with coronary artery disease

Objective

Statin- and exercise-therapy are both clinically beneficial by preventing cardiovascular events in patients with coronary artery disease (CAD). However, there is no information on the vascular effects of the combination of statins and exercise on arterial wall stiffness in CAD patients.

Methods

The present study is a sub-analysis of PRESET study that determined the effects of 20-week treatment with statins (rosuvastatin, n = 14, atorvastatin, n = 14) combined with regular exercise on arterial wall stiffness assessed by measurement of brachial and ankle pulse wave velocity (baPWV) in CAD patients.

Results

The combination of statins and regular exercise significantly improved exercise capacity, lipid profile, including low- and high-density lipoprotein cholesterol, and high-sensitivity C-reactive protein (hs-CRP), baPWV (baseline: 1747±355, at 20 weeks of treatment: 1627±271 cm/s, p = 0.008), and basophil count (baseline: 42±32, 20 weeks: 26±15 cells/µL, p = 0.007), but had no effect on blood pressure (baseline: 125±22, 20 weeks: 121±16 mmHg). Changes in baPWV correlated significantly with changes in basophil count (r = 0.488, p = 0.008), but not with age, lipids profile, exercise capacity, or hs-CRP.

Conclusion

In CAD patients, the combination treatment with statins and exercise resulted in significant amelioration of arterial wall stiffness, at least in part, through reduction of circulating basophils.     

Growth Stimulation of Iodide-Oxidizing α-<Emphasis Type="Italic">Proteobacteria</Emphasis> in Iodide-Rich Environments

α-Proteobacteria that can oxidize iodide (I⁻) to molecular iodine (I₂) have only been isolated from iodide-rich natural and artificial environments, i.e., natural gas brine waters and seawaters supplemented with iodide, respectively. To understand the growth characteristics of such iodide-oxidizing bacteria (IOB) under iodide-rich environments, microcosms comprising natural seawater and 1 mM iodide were prepared, and the succession of microbial communities was monitored by culture-independent techniques. PCR-denaturing gradient gel electrophoresis and 16S rRNA gene sequence analysis showed that bacteria closely related with known IOB were predominant in the microcosms after several weeks of incubation. Quantitative PCR analysis targeting specific 16S rRNA gene regions of IOB showed that the relative abundance of IOB in the microcosms was 6–76% of the total bacterial population, whereas that in natural seawater was less than 1%. When 10³ cells mL⁻¹ of IOB were inoculated into natural seawater supplemented with 0.1–1 mM iodide, significant growth (cell densities, 10⁵–10⁶ cells mL⁻¹) and I₂ production (6–32 μM) were observed. Interestingly, similar growth stimulation occurred when 12–44 μM of I₂ was added to seawater, instead of iodide. IOB were found to be more I₂ tolerant than the other heterotrophic bacteria in seawater. These results suggest that I₂ plays a key role in the growth stimulation of IOB in seawater. IOB could potentially attack other bacteria with I₂ to occupy their ecological niche in iodide-rich environments.     

Active Transport and Accumulation of Iodide by Newly Isolated Marine Bacteria

Iodide (I⁻)-accumulating bacteria were isolated from marine sediment by an autoradiographic method with radioactive ¹²⁵I⁻. When they were grown in a liquid medium containing 0.1 μM iodide, 79 to 89% of the iodide was removed from the medium, and a corresponding amount of iodide was detected in the cells. Phylogenetic analysis based on 16S rRNA gene sequences indicated that iodide-accumulating bacteria were closely related to Flexibacter aggregans NBRC15975 and Arenibacter troitsensis, members of the family Flavobacteriaceae. When one of the strains, strain C-21, was cultured with 0.1 μM iodide, the maximum iodide content and the maximum concentration factor for iodide were 220 ± 3.6 (mean ± standard deviation) pmol of iodide per mg of dry cells and 5.5 × 10³, respectively. In the presence of much higher concentrations of iodide (1 μM to 1 mM), increased iodide content but decreased concentration factor for iodide were observed. An iodide transport assay was carried out to monitor the uptake and accumulation of iodide in washed cell suspensions of iodide-accumulating bacteria. The uptake of iodide was observed only in the presence of glucose and showed substrate saturation kinetics, with an apparent affinity constant for transport and a maximum velocity of 0.073 μM and 0.55 pmol min⁻¹ mg of dry cells⁻¹, respectively. The other dominant species of iodine in terrestrial and marine environments, iodate (IO₃⁻), was not transported.