Scanning and transmission electron microscopy of human ejaculate spermatozoa with special reference to their abnormal forms

Summary Spermatozoa from fertile and infertile human ejaculates were observed under the scanning electron microscope. A parallel study of sections was performed by transmission electron microscope.The normal head shows under the scanning electron microscope vesicular elevations in the region of the acrosome and a smooth and rigid appearance corresponding to the postnuclear cap whose occurrence is confirmed under the transmission electron microscope. Immediately anterior to this cap a shallow furrow transverses the head. Duplicated, unusually large or small and deformed heads are found under the scanning electron microscope. Most of these abnormal heads show no surface structure suggesting an acrosome.The neck and middle piece are occasionally, though frequently in abnormal spermatozoa, covered by a cytoplasmic droplet. Otherwise, the mitochondrial sheath is recognized under the scanning electron microscope as a beaded thickening in the middle piece. The lack of mitochondria is manifested by a smooth middle piece thinner than the principal portion. Transmission electron microscopy of sections reveals various types of anomalies in the number of cores, core filaments and mitochondria embedded in the cytoplasmic droplets.Abnormalities in the principal portion of the tail such as duplication, unusual thickness and length are shown under the scanning electron microscope.The investigation indicates that scanning electron microscopy is suited for the clinical as well as cytological examination of human ejaculate spermatozoa.     

Using food network unfolding to evaluate food–web complexity in terms of biodiversity: theory and applications

Food–web complexity often hinders disentangling functionally relevant aspects of food–web structure and its relationships to biodiversity. Here, we present a theoretical framework to evaluate food–web complexity in terms of biodiversity. Food network unfolding is a theoretical method to transform a complex food web into a linear food chain based on ecosystem processes. Based on this method, we can define three biodiversity indices, horizontal diversity (D_H), vertical diversity (D_V) and range diversity (D_R), which are associated with the species diversity within each trophic level, diversity of trophic levels, and diversity in resource use, respectively. These indices are related to Shannon's diversity index (H′), where H′ = D_H + D_V ? D_R. Application of the framework to three riverine macroinvertebrate communities revealed that D indices, calculated from biomass and stable isotope features, captured well the anthropogenic, seasonal, or other within‐site changes in food–web structures that could not be captured with H′ alone.     

Nucleotide sequence of the cybB gene encoding cytochrome b561 in Escherichia coli K12

Summary The complete nucleotide sequence of the Escherichia coli cybB gene for diheme cytochrome b ₅₆₁ and its flanking region was determined. The cybB gene comprises 525 nucleotides and encodes a 175 amino acid polypeptide with a molecular weight of 20160. From its deduced amino acid sequence, cytochrome b ₅₆₁ is predicted to be very hydrophobic (polarity 33.7%) and to have three membrane spanning regions. Histidines, canonical ligand residues for protohemes, are localized in these regions, and the heme pockets are thought to be in the cytoplasmic membrane. No significant homology of the primary structure of cytochrome b ₅₆₁ with those of other bacterial b-type cytochromes was observed.     

Does the Upstream Region Possessing MULE-Like Sequence in Rice Upregulate PsbS1 Gene Expression?

The genomic nucleotide sequences of japonica rice (Sasanishiki and Nipponbare) contained about 2.7-kb unique region at the point of 0.4-kb upstream of the OsPsbS1 gene. In this study, we found that japonica rice with a few exceptions possessing such DNA sequences [denoted to OsMULE-japonica specific sequence (JSS)] is distinct by the presence of Mutator-like-element (MULE). Such sequence was absent in most of indica cultivars and Oryza glaberrima. In OsMULE-JSS1, we noted the presence of possible target site duplication (TSD; CTTTTCCAG) and about 80-bp terminal inverted repeat (TIR) near TSD. We also found the enhancement ofOsPsbS1 mRNA accumulation by intensified light, which was not associated with the DNA methylation status in OsMULE/JSS. In addition, O. rufipogon, possible ancestor of modern rice cultivars was found to compose PsbS gene of either japonica (minor) or indica (major) type. Transient gene expression assay showed that the japonica type promoter elevated a reporter gene activity than indica type.     

Prevalence and Risk Factors for Depressive Reaction among Resident Survivors after the Tsunami following the Great East Japan Earthquake,March 11, 2011

Objectives

The Great East Japan Earthquake caused a gigantic tsunami which devastated coastal areas of northern Japan on 11 March 2011. Despite the large number of ‘resident survivors’ who continued to reside in their damaged houses on the second or upper floors, research on the mental health of these individuals has been limited. This study explored the prevalence of depressive reaction and risk factors for depressive reaction among these resident survivors.

Methods

A cross-sectional household health support needs screening was conducted for resident survivors in Higashi-Matsushima city, Miyagi prefecture, two to four months after the tsunami. The health interview that was conducted including mental status, assessed by the Patient Health Questionnaire-2 (PHQ-2).

Results

Of 5,454 respondents, 8.1% had depressive reaction. After adjustment by the number of weeks from the tsunami and the mortality rate at each respondent''s place of residence, depressive reaction was significantly associated with house flooding below or above the ground floor (odds ratios of 1.92, 2.36, respectively), the unavailability of gas supply (odds ratio, 1.67), being female (odds ratio, 1.47), middle aged or elderly (odds ratios of 2.41, 2.42, respectively), regular intake of psychotropic medicine(s) since before the tsunami (odds ratio, 2.53) and the presence of one to five or more than six cohabiters (odds ratios of 0.61, 0.52, respectively).

Conclusions

The results suggest a considerable psychological burden (depressive reaction) following the tsunami among resident survivors. Special supports for families with psychiatric problems need to be considered among resident survivors. Restoration of lifeline utilities and the strengthening of social ties of persons living alone may help prevent depressive reaction among resident survivors after a tsunami.     

Effects of instantaneous and growth CO2 levels and abscisic acid on stomatal and mesophyll conductances

C₃ photosynthesis is often limited by CO₂ diffusivity or stomatal (g_s) and mesophyll (g_m) conductances. To characterize effects of stomatal closure induced by either high CO₂ or abscisic acid (ABA) application on g_m, we examined g_s and g_m in the wild type (Col‐0) and ost1 and slac1‐2 mutants of Arabidopsis thaliana grown at 390 or 780 μmol mol^?1 CO₂. Stomata of these mutants were reported to be insensitive to both high CO₂ and ABA. When the ambient CO₂ increased instantaneously, g_m decreased in all these plants, whereas g_s in ost1 and slac1‐2 was unchanged. Therefore, the decrease in g_m in response to high CO₂ occurred irrespective of the responses of g_s. g_m was mainly determined by the instantaneous CO₂ concentration during the measurement and not markedly by the CO₂ concentration during the growth. Exogenous application of ABA to Col‐0 caused the decrease in the intercellular CO₂ concentration (C_i). With the decrease in C_i, g_m did not increase but decreased, indicating that the response of g_m to CO₂ and that to ABA are differently regulated and that ABA content in the leaves plays an important role in the regulation of g_m.