Ophiocordyceps sessilis sp. nov., a new species of Ophiocordyceps on Camponotus ants in Japan

Ophiocordyceps sessilis, a new species of Ophiocordycipitaceae, Hypocreales, was found on Camponotus obscuripes ants, where the ants were primarily infected by another close relative, O. pulvinata. Morphological observation clearly indicated that O. sessilis and O. pulvinata are distinct species. Ophiocordyceps sessilis exhibited superficial development of perithecia and ascospore disarticulation into part-spores, not known in O. pulvinata. Nucleotide sequence data suggested that O. sessilis belongs in Ophiocordyceps, Ophiocordycipitaceae. Molecular data also indicated that O. sessilis is a close relative of O. cuboidea, O. prolifica, O. paracuboidea, and O. ryogamiensis, which are all known to produce part-spores. Since O. sessilis is always associated with ants infected by O. pulvinata, O. sessilis may be a hyperparasite of O. pulvinata.     

Role of galactolipid biosynthesis in coordinated development of photosynthetic complexes and thylakoid membranes during chloroplast biogenesis in Arabidopsis

The galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the predominant lipids in thylakoid membranes and indispensable for photosynthesis. Among the three isoforms that catalyze MGDG synthesis in Arabidopsis thaliana, MGD1 is responsible for most galactolipid synthesis in chloroplasts, whereas MGD2 and MGD3 are required for DGDG accumulation during phosphate (Pi) starvation. A null mutant of Arabidopsis MGD1 (mgd1‐2), which lacks both galactolipids and shows a severe defect in chloroplast biogenesis under nutrient‐sufficient conditions, accumulated large amounts of DGDG, with a strong induction of MGD2/3 expression, during Pi starvation. In plastids of Pi‐starved mgd1‐2 leaves, biogenesis of thylakoid‐like internal membranes, occasionally associated with invagination of the inner envelope, was observed, together with chlorophyll accumulation. Moreover, the mutant accumulated photosynthetic membrane proteins upon Pi starvation, indicating a compensation for MGD1 deficiency by Pi stress‐induced galactolipid biosynthesis. However, photosynthetic activity in the mutant was still abolished, and light‐harvesting/photosystem core complexes were improperly formed, suggesting a requirement for MGDG for proper assembly of these complexes. During Pi starvation, distribution of plastid nucleoids changed concomitantly with internal membrane biogenesis in the mgd1‐2 mutant. Moreover, the reduced expression of nuclear‐ and plastid‐encoded photosynthetic genes observed in the mgd1‐2 mutant under Pi‐sufficient conditions was restored after Pi starvation. In contrast, Pi starvation had no such positive effects in mutants lacking chlorophyll biosynthesis. These observations demonstrate that galactolipid biosynthesis and subsequent membrane biogenesis inside the plastid strongly influence nucleoid distribution and the expression of both plastid‐ and nuclear‐encoded photosynthetic genes, independently of photosynthesis.     

Chemical magnetoreception: bird cryptochrome 1a is excited by blue light and forms long-lived radical-pairs

Cryptochromes (Cry) have been suggested to form the basis of light-dependent magnetic compass orientation in birds. However, to function as magnetic compass sensors, the cryptochromes of migratory birds must possess a number of key biophysical characteristics. Most importantly, absorption of blue light must produce radical pairs with lifetimes longer than about a microsecond. Cryptochrome 1a (gwCry1a) and the photolyase-homology-region of Cry1 (gwCry1-PHR) from the migratory garden warbler were recombinantly expressed and purified from a baculovirus/Sf9 cell expression system. Transient absorption measurements show that these flavoproteins are indeed excited by light in the blue spectral range leading to the formation of radicals with millisecond lifetimes. These biophysical characteristics suggest that gwCry1a is ideally suited as a primary light-mediated, radical-pair-based magnetic compass receptor.     

Isolation of putative glycoprotein gene from early somatic embryo of carrot and its possible involvement in somatic embryo development

Somatic embryogenesis is a unique process in plant cells. For example, embryogenic cells (EC) of carrot (Daucus carota) maintained in a medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) regenerate whole plants via somatic embryogenesis after the depletion of 2,4-D. Although some genes such as C-ABI3 and C-LEC1 have been found to be involved in somatic embryogenesis, the critical molecular and cellular mechanisms for somatic embryogenesis are unknown. To characterize the early mechanism in the induction of somatic embryogenesis, we isolated genes expressed during the early stage of somatic embryogenesis after 2,4-D depletion. Subtractive hybridization screening and subsequent RNA gel blot analysis suggested a candidate gene, Carrot Early Somatic Embryogenesis 1 (C-ESE1). C-ESE1 encodes a protein that has agglutinin and S-locus-glycoprotein domains and its expression is highly specific to primordial cells of somatic embryo. Transgenic carrot cells with reduced expression of C-ESE1 had wide intercellular space and decreased polysaccharides on the cell surface and showed delayed development in somatic embryogenesis. The importance of cell-to-cell attachment in somatic embryogenesis is discussed.     

Real-time quantitative PCR assay on bacterial DNA: In a model soil system and environmental samples

Real-time quantitative PCR (RTQ-PCR) was used to quantify the bacterial target DNA extracted by three commonly used DNA extraction protocols (bead mill homogenization, grinding in presence of liquid nitrogen and hot detergent SDS based enzymatic lysis). For the purpose of our study, pure culture of Bacillus cereus (model organism), sterilized soil seeded with a known amount of B. cereus (model soil system) and samples from woodland and grassland (environmental samples) were chosen to extract DNA by three different protocols. The extracted DNA was then quantified by RTQ-PCR using 16S rDNA specific universal bacterial primers. The standard curve used for the quantification by RTQ-PCR was linear and revealed a strong linear relationship (r(2)=0.9968) with a higher amplification efficiency, e5=1.02. High resolution gel electrophoresis was also carried out to observe the effect of these extraction methods on diversity analysis. For the model soil system, the liquid nitrogen method showed the highest target DNA copy number (1.3 x 10(9) copies/microl). However, for both the environmental samples, the bead beating method was found to be suitable on the basis of the high target DNA copy numbers (5.38 x 10(9) and 4.01 x 10(8) copies/ml for woodland and grassland respectively), high yield (6.4 microg/g and 1.76 microg/g of soil for woodland and grassland respectively) and different band patterns on high resolution gel electrophoresis suggesting an overall high extraction efficiency. This difference in the extraction efficiency between the model soil system and environmental samples may be attributed to different affinity of seeded and native DNA to soil particles.     

Quinapril inhibits progression of heart failure and fibrosis in rats with dilated cardiomyopathy after myocarditis

The cardioprotective properties of quinapril, an angiotensin-converting enzyme inhibitor, were studied in a rat model of dilated cardiomyopathy. Twenty-eight days after immunization of pig cardiac myosin, four groups rats were given 0.2 mg/kg (Q0.2, n = 11), 2 mg/kg (Q2, n = 11) or 20 mg/kg (Q20, n = 11) of quinapril or vehicle (V, n = 15) orally once a day. After 1 month, left ventricular end-diastolic pressure (LVEDP), ±dP/dt, area of myocardial fibrosis, and myocardial mRNA expression of transforming growth factor (TGF)-1, collagen-III and fibronectin were measured. Four of 15 (27%) rats in V and two of 11 (18%) in Q0.2 died. None of the animals in Q2 or Q20 died. The LVEDP was higher and ±dP/dt was lower in V (14.1 ± 2.0 mmHg and +2409 ± 150/–2318 ± 235 mmHg/sec) than in age-matched normal rats (5.0 ± 0.6 mmHg and +6173 ± 191/–7120 ± 74 mmHg/sec; all p < 0.01). After quinapril treatment, LVEDP was decreased and ±dP/dt was increased in a dose-dependent manner (10.8 ± 1.8 mmHg and +3211 ± 307/–2928 ± 390 mmHg/sec in Q0.2, 9.4 ± 1.5 mmHg and +2871 ± 270/–2966 ± 366 mmHg/sec in Q2, and 6.6 ± 1.5 mmHg, and +3569 ± 169/–3960 ± 203 mmHg/sec in Q20). Increased expression levels of TGF-1, collagen-III and fibronectin mRNA in V were reduced in Q20. Quinapril improved survival rate and cardiac function in rats with dilated cardiomyopathy after myocarditis. Furthermore, myocardial fibrosis was regressed and myocardial structure returned to nearly normal in animals treated with quinapril.     

Genetic analysis ofCochliobolus heterostrophus polyoxin-resistant mutants

Nine polyoxin-resistant mutants ofCochliobolus heterostrophus were isolated after ethyl methanesulphonate mutagenesis. All were highly resistant to polyoxin (MIC≥1,600 ppm). Crosses between the mutants and a wild-type strain revealed that the resistance trait was inherited to the offsprings in different fashions. Four of the mutant strains inherited polyoxin resistance in a 1∶1 segregation ratio, indicating that the phenotypes in these strains were due to alteration at a single locus. Allelism tests revealed four new loci,Pol1, Pol2, Pol3 andPol4, for polyoxin resistance in these mutant strains. The genes responsible for the phenotypes of the other five mutant strains were not determined, because of extremely slow growth of progenies in one cross, sterility in another cross, and inexplicable responses to polyoxin of the progenies in the other crosses. No linkage was detected between the genes for polyoxin resistance and mating type.     

Paleobiogeographical implications of inner bay Ostracoda during the Late Pleistocene Shimosueyoshi transgression,central Japan,with significance of its migration and disappearance in eastern Asia

A total of 79 ostracode species were recognized from the embayment sediments deposited during the Late Pleistocene Shimosueyoshi transgression in central Japan. The most dominant species was Neomonoceratina delicata, now abundant in tropical inner bays of the Ryukyu Islands, the South China Sea and southeastern Asia. Bicornucythere bisanensis, widely dominant species in enclosed middle muddy bays of temperate climatic zones in Japan and northern China, was also abundant in the middle and upper sequences. Most of the other main species were assigned to the “Japonic elements” and are presently common in tropical or subtropical and temperate shallow seas near the Japanese Islands. Four ostracode biofacies were identified using the Q-mode cluster analysis. A change in water depth was clearly revealed in the study sequence, based on the vertical changes in the biofacies and the relative abundances of fossil ostracode species. The single most dominant species, N. delicata, does not currently exist in the Japanese Islands north of the Tokara Strait (Watase's line: one of zoological lines of demarcation), in southern Japan. Based on a compilation of fossil and recent distribution records, it is believed that N. delicata migrated from the south of the Tokara Strait by the marine oxygen isotope stage (MIS) 11 (～ 430 ka), dominated other species in enclosed muddy bays and then spread to the northernmost areas during the MIS 5. However, almost all populations of this species probably disappeared north of the Tokara Strait during the Last Glacial Maximum due to a decrease in water temperature. This species could not survive colder water temperature and could not migrate north through the Tokara Strait during the postglacial transgression because the strait has been deep and wide since the Early Pleistocene. We conclude that this species lived commonly during the glacial stages of MIS 10, 8 and 6 north of the Tokara Strait because of the favorable water temperature for reproduction.     

Japanese Lifestyle during Childhood Prevents the Future Development of Obesity among Japanese-Americans

Objective

To evaluate whether a Japanese lifestyle during childhood could protect against the future development of obesity-associated metabolic diseases by comparing native Japanese with Japanese-Americans in whom genetic factors are the same.

Methods

Study subjects were 516 native Japanese and 781 Japanese-Americans who underwent medical examinations between 2007 and 2010. Japanese-Americans were divided into 444 first-generation immigrants (JA-1), who were born in Japan, and 337 second- or later-generation descendants (JA-2), who were born in the United States. The JA-2 group was then divided into the kibei subgroup (N = 79), who had moved to Japan before the age of 18 years and later returned to the United States, and the non-kibei subgroup (N = 258), who had never lived in Japan.

Results

The JA-2 group had the highest percentages of obesity, metabolic syndrome, and type 2 diabetes compared with native Japanese and JA-1. Furthermore, among JA-2, the prevalence of obesity and metabolic syndrome in the kibei subgroup was significantly lower than that in the non-kibei subgroup. The prevalence of diabetes in the kibei subgroup also tended to be lower than in the non-kibei subgroup.

Conclusions

The prevalence of obesity and metabolic diseases differed with residence in Japan during childhood among Japanese-Americans. These findings indicate the possibility that Japanese lifestyle during childhood could reduce the future risks for obesity-associated metabolic diseases.