Class I Myosins Have Overlapping and Specialized Functions in Left-Right Asymmetric Development in Drosophila

The class I myosin genes are conserved in diverse organisms, and their gene products are involved in actin dynamics, endocytosis, and signal transduction. Drosophila melanogaster has three class I myosin genes, Myosin 31DF (Myo31DF), Myosin 61F (Myo61F), and Myosin 95E (Myo95E). Myo31DF, Myo61F, and Myo95E belong to the Myosin ID, Myosin IC, and Myosin IB families, respectively. Previous loss-of-function analyses of Myo31DF and Myo61F revealed important roles in left–right (LR) asymmetric development and enterocyte maintenance, respectively. However, it was difficult to elucidate their roles in vivo, because of potential redundant activities. Here we generated class I myosin double and triple mutants to address this issue. We found that the triple mutant was viable and fertile, indicating that all three class I myosins were dispensable for survival. A loss-of-function analysis revealed further that Myo31DF and Myo61F, but not Myo95E, had redundant functions in promoting the dextral LR asymmetric development of the male genitalia. Myo61F overexpression is known to antagonize the dextral activity of Myo31DF in various Drosophila organs. Thus, the LR-reversing activity of overexpressed Myo61F may not reflect its physiological function. The endogenous activity of Myo61F in promoting dextral LR asymmetric development was observed in the male genitalia, but not the embryonic gut, another LR asymmetric organ. Thus, Myo61F and Myo31DF, but not Myo95E, play tissue-specific, redundant roles in LR asymmetric development. Our studies also revealed differential colocalization of the class I myosins with filamentous (F)-actin in the brush border of intestinal enterocytes.     

Molecular species of cerebrosides in fruiting bodies of Lentinus edodes and their biological activity

Cerebroside fraction was obtained from fresh fruiting bodies of Lentinus edodes and separated into ten molecular species by reverse-phase high-performance liquid chromatography. The species were identified by GLC, GC-MS and NMR. Their component glycosides and sphingoids were uniformly glucose and (4E,8E)-9-methyl-4,8-sphingadienine, respectively. The component fatty acids were 2-hydroxy acids with the carbon chain length of 16, 15, 14, 18, 24, 17, 25, 26, 22 and 23 (from major to minor). The cerebrosides with the C14-18 fatty acids showed strong fruiting-inducing activity in Schizophyllum commune. Those with the C22 and C23 ones had one-eighth and one-sixteenth of the activity, respectively, and those with C24-26 had no detectable activity. 22 and 23 must be the carbon chain lengths of the component fatty acid of the sphingolipids critical for expression of biological activity.     

CORTICAL F‐ACTIN REORGANIZATION AND A CONTRACTILE RING‐LIKE STRUCTURE FOUND DURING THE CELL CYCLE IN THE RED CRYPTOMONAD,PYRENOMONAS HELGOLANDII1

Cortical F‐actin reorganization during the cell cycle was observed in Pyrenomonas helgolandii U. J. Santore (SAG 28.87) for the first time in Cryptophyta using fluorescein‐isothiocyanate (FITC)–phalloidin staining. In interphase, a number of F‐actin bundles were observed as straight lines running parallel to the long axis of the cell on the cell cortical region. They extended from an F‐actin bundle that runs along the margin of the vestibulum. Although the F‐actin bundles running parallel to the long axis of the cell disappeared during anaphase, they gradually reappeared in telophase. By contrast, the F‐actin bundle along the vestibulum margin remained visible during cytokinesis and dynamically changed following the enlargement of the vestibulum, suggesting that F‐actin was involved in the mechanism of vestibulum enlargement. F‐actins were not found in the cytoplasmic and nucleoplasmic regions throughout the cell cycle. In addition, a contractile ring‐like structure appeared at the cleavage furrow during cytokinesis. Treatment with cytochalasin B and latrunculin B significantly inhibited the formation of cleavage furrow, resulting in forming an abnormal cell with two nuclei, suggesting that cytokinesis in P. helgolandii is controlled by the contractile ring‐like structure constituted of F‐actin.     

Molecular phylogeny of Punctaria mageshimensis reveals evidence for its transfer to Spatoglossum as S. mageshimense (Dictyotales,Phaeophyceae)

Taxonomy of the little‐studied brown algal species Punctaria mageshimensis (Ectocarpales s.l.) was reexamined by molecular phylogeny and morphology. In the genetic analyses of newly collected specimens using plastid rbcL and psaA gene sequences, the specimens morphologically referable to P. mageshimensis were phylogenetically distant from Ectocarpales s.l. and were included in the clade of Spatoglossum (Dictyotales). Morphological reexamination of the type specimen and newly collected specimens confirmed its systematic position in Dictyotales: Branched thallus; cushion‐shaped rhizoidal holdfast occasionally forming secondary holdfast at the bottom of the thallus; many discoidal plastids without pyrenoid per cell; tetrasporangium‐like reproductive structures with dark, homogeneous cell content; occurrence of hair tufts. Genetically P. mageshimensis was most related to a reported sequence of Spatoglossum asperum, but P. mageshimensis was considerably different from S. asperum as well as other known Spatoglossum species in the deep habitat and in having scarcely‐branched lanceolate and considerably thickened thallus. In conclusion, we propose the transfer of P. mageshimensis to Spatoglossum as S. mageshimense comb. nov.     

Genetic relationships of cichlid fishes from Lake Malawi based on mitochondrial DNA sequences

Limnology - The purpose of this study was to estimate the genetic distance, diversity and relationship of two large groups of Malawian cichlid, ‘mbuna’ living in rocky area and feeding...     

Effectiveness of enhanced cognitive behavior therapy for bulimia nervosa in Japan: a randomized controlled trial protocol

Although fatigue is a common and distressing symptom in cancer survivors, the mechanism of fatigue is not fully understood. Therefore, this study aims to investigate the relation between the fatigue and mindfulness of breast cancer survivors using anxiety, depression, pain, loneliness, and sleep disturbance as mediators. Path analysis was performed to examine direct and indirect associations between mindfulness and fatigue. Participants were breast cancer survivors who visited a breast surgery department at a university hospital in Japan for hormonal therapy or regular check-ups after treatment. The questionnaire measured cancer-related-fatigue, mindfulness, anxiety, depression, pain, loneliness, and sleep disturbance. Demographic and clinical characteristics were collected from medical records. Two-hundred and seventy-nine breast cancer survivors were registered, of which 259 answered the questionnaire. Ten respondents with incomplete questionnaire data were excluded, resulting in 249 participants for the analyses. Our final model fit the data well (goodness of fit index = .993; adjusted goodness of fit index = .966; comparative fit index = .999; root mean square error of approximation = .016). Mindfulness, anxiety, depression, pain, loneliness, and sleep disturbance were related to fatigue, and mindfulness had the most influence on fatigue (β = − .52). Mindfulness affected fatigue not only directly but also indirectly through anxiety, depression, pain, loneliness, and sleep disturbance. The study model helps to explain the process by which mindfulness affects fatigue. Our results suggest that mindfulness has both direct and indirect effects on the fatigue of breast cancer survivors and that mindfulness can be used to more effectively reduce their fatigue. It also suggests that health care professionals should be aware of factors such as anxiety, depression, pain, loneliness, and sleep disturbance in their care for fatigue of breast cancer survivors. This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN number. 000027720) on June 12, 2017.     

Cyanobacterial Cell Lineage Analysis of the Spatiotemporal hetR Expression Profile during Heterocyst Pattern Formation in Anabaena sp. PCC 7120

Diazotrophic heterocyst formation in the filamentous cyanobacterium, Anabaena sp. PCC 7120, is one of the simplest pattern formations known to occur in cell differentiation. Most previous studies on heterocyst patterning were based on statistical analysis using cells collected or observed at different times from a liquid culture, which would mask stochastic fluctuations affecting the process of pattern formation dynamics in a single bacterial filament. In order to analyze the spatiotemporal dynamics of heterocyst formation at the single filament level, here we developed a culture system to monitor simultaneously bacterial development, gene expression, and phycobilisome fluorescence. We also developed micro-liquid chamber arrays to analyze multiple Anabaena filaments at the same time. Cell lineage analyses demonstrated that the initial distributions of hetR::gfp and phycobilisome fluorescence signals at nitrogen step-down were not correlated with the resulting distribution of developed heterocysts. Time-lapse observations also revealed a dynamic hetR expression profile at the single-filament level, including transient upregulation accompanying cell division, which did not always lead to heterocyst development. In addition, some cells differentiated into heterocysts without cell division after nitrogen step-down, suggesting that cell division in the mother cells is not an essential requirement for heterocyst differentiation.