Botryosphaeria spp. isolated from apple and several deciduous fruit trees are divided into three groups based on the production of warts on twigs, size of conidia, and nucleotide sequences of nuclear ribosomal DNA ITS regions

We examined the phytopathological and biological characters ofBotryosphaeria spp. isolated from apples and other deciduous fruit trees, and determined the nucleotide sequences of their rDNA ITS regions. TheBotryosphaeria isolates from deciduous fruit trees can be divided into three groups based on their production of warts on twigs, size of the conidia, and nucleotide sequences of rDNA ITS 1, ITS 2 and 5.8S rDNA. Isolates ofBotryosphaeria in ITS group A produced conidia of intermediate size and showed warts on infected twigs prior to the development of ring rot on fruit. This group was common on deciduous fruit trees in Japan as a causal agent of ring rot and wart bark diseases of apples and pears; and it appears similar to theB. dothidea from the US that was isolated from apple exhibiting white rot. The ITS group BBotryosphaeria produced small conidia and induced shoot blight without wart development prior to the development of ring rot on fruit. This group was localized on pear, persimmon, and kiwi fruit in restricted areas of Japan. The ITS group CBotryosphaeria consisted ofB. obtusa, the causal agent of apple black rot in the US, which produced large dark brown conidia.     

Plasmid Copy Number Underlies Adaptive Mutability in Bacteria

The origin of mutations under selection has been intensively studied using the Cairns-Foster system, in which cells of an Escherichia coli lac mutant are plated on lactose and give rise to 100 Lac⁺ revertants over several days. These revertants have been attributed variously to stress-induced mutagenesis of nongrowing cells or to selective improvement of preexisting weakly Lac⁺ cells with no mutagenesis. Most revertant colonies (90%) contain stably Lac⁺ cells, while others (10%) contain cells with an unstable amplification of the leaky mutant lac allele. Evidence is presented that both stable and unstable Lac⁺ revertant colonies are initiated by preexisting cells with multiple copies of the F′lac plasmid, which carries the mutant lac allele. The tetracycline analog anhydrotetracycline (AnTc) inhibits growth of cells with multiple copies of the tetA gene. Populations with tetA on their F′lac plasmid include rare cells with an elevated plasmid copy number and multiple copies of both the tetA and lac genes. Pregrowth of such populations with AnTc reduces the number of cells with multiple F′lac copies and consequently the number of Lac⁺ colonies appearing under selection. Revertant yield is restored rapidly by a few generations of growth without AnTc. We suggest that preexisting cells with multiple F′lac copies divide very little under selection but have enough energy to replicate their F′lac plasmids repeatedly until reversion initiates a stable Lac⁺ colony. Preexisting cells whose high-copy plasmid includes an internal lac duplication grow under selection and produce an unstable Lac⁺ colony. In this model, all revertant colonies are initiated by preexisting cells and cannot be stress induced.     

Reevaluation of erythropoietin production by the nephron

Erythropoietin production has been reported to occur in the peritubular interstitial fibroblasts in the kidney. Since the erythropoietin production in the nephron is controversial, we reevaluated the erythropoietin production in the kidney. We examined mRNA expressions of erythropoietin and HIF PHD2 using high-sensitive in situ hybridization system (ISH) and protein expression of HIF PHD2 using immunohistochemistry in the kidney. We further investigated the mechanism of erythropoietin production by hypoxia in vitro using human liver hepatocell (HepG2) and rat intercalated cell line (IN-IC cells). ISH in mice showed mRNA expression of erythropoietin in proximal convoluted tubules (PCTs), distal convoluted tubules (DCTs) and cortical collecting ducts (CCDs) but not in the peritubular cells under normal conditions. Hypoxia induced mRNA expression of erythropoietin largely in peritubular cells and slightly in PCTs, DCTs, and CCDs. Double staining with AQP3 or AE1 indicated that erythropoietin mRNA expresses mainly in β-intercalated or non α/non β-intercalated cells of the collecting ducts. Immunohistochemistry in rat showed the expression of HIF PHD2 in the collecting ducts and peritubular cells and its increase by anemia in peritubular cells. In IN-IC cells, hypoxia increased mRNA expression of erythropoietin, erythropoietin concentration in the medium and protein expression of HIF PHD2. These data suggest that erythropoietin is produced by the cortical nephrons mainly in the intercalated cells, but not in the peritubular cells, in normal hematopoietic condition and by mainly peritubular cells in hypoxia, suggesting the different regulation mechanism between the nephrons and peritubular cells.     

A Simple Force-Motion Relation for Migrating Cells Revealed by Multipole Analysis of Traction Stress

For biophysical understanding of cell motility, the relationship between mechanical force and cell migration must be uncovered, but it remains elusive. Since cells migrate at small scale in dissipative circumstances, the inertia force is negligible and all forces should cancel out. This implies that one must quantify the spatial pattern of the force instead of just the summation to elucidate the force-motion relation. Here, we introduced multipole analysis to quantify the traction stress dynamics of migrating cells. We measured the traction stress of Dictyostelium discoideum cells and investigated the lowest two moments, the force dipole and quadrupole moments, which reflect rotational and front-rear asymmetries of the stress field. We derived a simple force-motion relation in which cells migrate along the force dipole axis with a direction determined by the force quadrupole. Furthermore, as a complementary approach, we also investigated fine structures in the stress field that show front-rear asymmetric kinetics consistent with the multipole analysis. The tight force-motion relation enables us to predict cell migration only from the traction stress patterns.     

A food-supply device for maintaining Cotesia vestalis,a larval parasitoid of the diamondback moth Plutella xylostella,in greenhouses

The limited availability of sugar sources (e.g., flowers) in greenhouses may affect biological pest control by parasitoid wasps. However, few studies have focused on feeding devices to provide parasitoids with sugar foods. We investigated the accessibility of a yellow-colored bottle-type feeding device to adult Cotesia vestalis (Halliday), a larval endoparasitoid of the diamondback moth Plutella xylostella (L.). All parasitoids died within four days in a room with no sugar source, whereas 66.7 % of individuals survived if a bottle-type feeding device providing honey solution was installed. We also investigated female longevity in response to different sugar solutions presented in a bottle-type feeding device. Honey and sugar mixtures (glucose and fructose) improved female longevity (38.4 and 39.2 days, respectively) much more than water (3.1 days), indicating these feeding devices containing sugar foods to be potentially useful for maintaining C. vestalis in greenhouses where natural food sources are limited.     

Evaluation of Differences in Automated QT/QTc Measurements between Fukuda Denshi and Nihon Koden Systems

Background

Automatic measurement becomes a preference, and indeed a necessity, when analyzing 1000 s of ECGs in the setting of either drug-inducing QT prolongation screening or genome-wide association studies of QT interval. The problem is that individual manufacturers apply different computerized algorithms to measure QT interval. We conducted a comparative study to assess the outcomes with different automated measurements of QT interval between ECG machine manufacturers and validated the related heart rate correction methods.

Methods and Results

Herein, we directly compared these different commercial systems using 10,529 Fukuda Denshi ECGs and 72,754 Nihon Kohden ECGs taken in healthy Japanese volunteers. Log-transformed data revealed an equal optimal heart rate correction formula of QT interval for Fukuda Denshi and Nihon Kohden, in the form of QTc = QT/RR^−0.347. However, with the raw data, the optimal heart rate correction formula of QT interval was in the form of QTc = QT+0.156×(1-RR) for Fukuda Denshi and QTc = QT+0.152×(1-RR) for Nihon Kohden. After optimization of heart rate correction of QT interval by the linear regression model using either log-transformed data or raw data, QTc interval was ∼10 ms longer in Nihon Kohden ECGs than in those recorded on Fukuda Denshi machines. Indeed, regression analysis revealed that differences in the ECG machine used had up to a two-fold larger impact on QT variation than gender difference. Such an impact is likely to be of considerable importance when ECGs for a given individual are recorded on different machines in the setting of multi-institutional joint research.

Conclusions

We recommend that ECG machines of the same manufacturer should be used to measure QT and RR intervals in the setting of multi-institutional joint research. It is desirable to unify the computer algorithm for automatic QT and RR measurements from an ECG.     

Relationship between Lifetime Suicide Attempts and Schizotypal Traits in Patients with Schizophrenia

Patients with schizophrenia are at increased risk for suicide. Various risk factors for suicide have been reported in schizophrenia; however, few studies have examined the association between personality traits and suicidal behavior. We administered the Schizotypal Personality Questionnaire (SPQ) to 87 Japanese patients with schizophrenia (49 males; mean age 38.1±10.6 years) with and without a history of suicide attempts (SA and nSA groups, respectively), and 322 controls (158 males; mean age 40.8±13.9 years). As expected, an analysis of covariance (ANCOVA) controlling for age and sex showed that all SPQ indices (total SPQ score and all three factors, i.e., cognitive-perceptual, interpersonal, and disorganized) were significantly higher in patients with schizophrenia (SA+nSA groups), than controls (p<0.001 for all comparisons). Furthermore, there were significant differences in the total score and the interpersonal and disorganized factors between the SA and nSA groups (nSA<SA, p<0.01 for all comparisons). Receiver operating characteristic analysis showed that a total SPQ score of 33.5 was the optimal cut-off value to discriminate the SA group from the nSA group (χ²[1] = 10.6, p = 0.002, odds ratio: 4.7, 95% confidence interval: 1.8–12.1, sensitivity: 0.70, specificity: 0.67). These results suggest that high schizotypy is associated with lifetime suicide attempts, and that the total SPQ score might be useful to assess the risk of suicide attempt in patients with schizophrenia.     

Temporal and spatial regulation of phosphoinositide signaling mediates cytokinesis

Polarity is a prominent feature of both chemotaxis and cytokinesis. In chemotaxis, polarity is established by local accumulation of PI(3,4,5)P3 at the cell's leading edge, achieved through temporal and spatial regulation of PI3 kinases and the tumor suppressor, PTEN. We find that as migrating D. discoideum cells round up to enter cytokinesis, PI(3,4,5)P3 signaling is uniformly suppressed. Then, as the spindle and cell elongate, PI3 kinases and PTEN move to and function at the poles and furrow, respectively. Cell lines lacking both of these enzymatic activities fail to modulate PI(3,4,5)P3 levels, are defective in cytokinesis, and cannot divide in suspension. The cells continue to grow and duplicate their nuclei, generating large multinucleate cells. Furrows that fail to ingress between nuclei are unable to stably accumulate myosin filaments or suppress actin-filled ruffles. We propose that phosphoinositide-linked circuits, similar to those that bring about asymmetry during cell migration, also regulate polarity in cytokinesis.