Cell shape controls rheotaxis in small parasitic bacteria

Mycoplasmas, a group of small parasitic bacteria, adhere to and move across host cell surfaces. The role of motility across host cell surfaces in pathogenesis remains unclear. Here, we used optical microscopy to visualize rheotactic behavior in three phylogenetically distant species of Mycoplasma using a microfluidic chamber that enabled the application of precisely controlled fluid flow. We show that directional movements against fluid flow occur synchronously with the polarized cell orienting itself to be parallel against the direction of flow. Analysis of depolarized cells revealed that morphology itself functions as a sensor to recognize rheological properties that mimic those found on host-cell surfaces. These results demonstrate the vital role of cell morphology and motility in responding to mechanical forces encountered in the native environment.     

Growth hormone-releasing factor releases ACTH from an AtT-20 mouse pituitary tumor cell line but not from normal pituitary cells

Corticotropin-releasing factor (CRF) and both human pancreatic growth hormone-releasing factor (hp-GRF) and rat hypothalamic GRF (rh-GRF) stimulated ACTH release from neoplastic AtT-20 mouse pituitary tumor cells in a dose-dependent fashion, with CRF inducing a 10-fold increase and GRF a maximal increment of approximately one-half that of CRF. Neither rh-GRF nor hp-GRF induced ACTH release in normal anterior pituitary cells. Pretreatment with either dexamethasone or somatostatin prior to the addition of rh-GRF inhibited the increase in ACTH release. Both ovine CRF and rh-GRF stimulated adenosine 3,5-monophosphate production in AtT-20 cells. The weak but clearly discernible effect of GRF on ACTH release from AtT-20 cells may be due to an abnormality in the AtT-20 cell receptor.     

Cerebral Blood Flow Threshold and Regional Heterogeneity of Heat Shock Protein 72 Induction Following Transient Forebrain Ischemia in Rats

Heat shock proteins (HSPs) induced by brain ischemia may play an important role in neuroprotection from neuronal degeneration. In this study, we examined the cerebral blood flow (CBF) threshold to produce regional differences in HSP72 induction after transient forebrain ischemia in spontaneously hypertensive rats (SHRs). Female SHRs were subjected to 20 min of cerebral ischemia induced by bilateral carotid artery occlusion. The CBF was measured by laser Doppler flowmetry. At forty-eight hours after cerebral ischemia and reperfusion, the rats were decapitated and the brains were removed. Specific areas (hippocampal CA1, CA2-3, dentate gyrus, dorsolateral and ventromedial striatum, and parietal cortex) were thereafter dissected from the brain. The amounts of HSP72 in these samples were determined using Western blot analysis. In the hippocampus, HSP72 was induced when the CBF decreased to less than 18–25% of the resting level. The mean values of HSP72 produced in the CA1 area, CA2-3 area, and the dentate gyrus following ischemia and reperfusion treatment were 4.44 ± 1.43 (±SD) ng/g prtein, 3.51 ± 0.72 ng/g protein and 3.77 ± 1.05 ng/g protein, respectively. In the parietal cortex, the amount of HSP72 induction was less pronounced (2.55 ± 0.40 ng/g protein), while HSP72 was hardly detected at all in the striatum, even under conditions of very severe CBF reduction and reperfusion. We demonstrated the existence of both a CBF threshold (i.e., approximately 20% of the resting level) for HSP72 induction and regional heterogeneity for the induction of HSP72 protein.     

Ca2+/calmodulin-regulated nitric oxide synthases.

NO synthase (NOS) catalyzes the oxidation of L-arginine to L-citrulline and nitric oxide (NO) or a NO-releasing compound. At least three isoforms of NOS exist (types I-III). The activities of the type I isoform purified from brain and the type III isoform purified from endothelial cells are regulated by the intracellular free calcium concentration ([Ca2+]i) and the Ca(2+)-binding protein calmodulin. At resting [Ca2+]i, both isozymes are inactive; they become fully active at [Ca2+]i greater than or equal to 500 nM Ca2+. Longer lasting increases in [Ca2+]i may downregulate NO formation, for in vitro phosphorylation by Ca2+/calmodulin protein kinase II decreases the Vmax of NOS. Besides the conversion of L-arginine, type I NOS, Ca2+/calmodulin dependently, generates H2O2 and reduces cytochrome c/P450. Other redox activities, i.e. the reduction of nitroblue tetrazolium to diformazan (NADPH-diaphorase) or of quinoid-dihydrobiopterin to tetrahydrobiopterin, by NOS appear to be Ca2+/calmodulin-independent.     

Identification of a major glucose transporter in Flavobacterium johnsoniae: Inhibition of F. johnsoniae colony spreading by glucose uptake

Many members of the phylum Bacteroidetes, such as Flavobacterium johnsoniae, can glide over a solid surface: an ability called gliding motility. It can be usually observed on agar plates as thin, flat, spreading colonies with irregular, feathery edges; this phenomenon is called colony spreading. Colony spreading of F. johnsoniae on 1.5% agar plates containing poor nutrients is dose‐dependently inhibited by addition of D‐glucose, as previously reported. Accordingly, here, we created mutants (by transposon mutagenesis) that partially suppressed glucose‐mediated inhibition of colony spreading. Among the isolates, we found that one had a transposon insertion in Fjoh_4565, tentatively named mfsA, which encodes a major facilitator superfamily (MFS) transporter previously shown to be required for growth on glucose, N‐acetyl‐glucosamine, and chitin. We constructed an mfsA deletion mutant and found that the mutant showed no glucose‐mediated acceleration of growth or glucose uptake. The mfsA gene complemented the phenotype of a glucose‐negative Escherichia coli. These results suggest that the mfsA gene encodes the sole MFS transporter of glucose in F. johnsoniae and that glucose uptake is partially required for the glucose‐mediated inhibition of F. johnsoniae colony spreading.

     

Synthesis of polyozellin,a prolyl oligopeptidase inhibitor,and its structural revision

Polyozellin is a p-terphenyl compound which was isolated from Polyozellus multiplex, and exhibits an inhibitory activity against prolyl oligopeptidase (POP). Its structure was assigned as 1 having a p-terphenyl skeleton including a p-substituted dibenzofuran moiety by spectroscopic analyses and chemical means. This paper describes the total syntheses of the proposed structure 1 for polyozellin and its o-isomer 2, revising the structure of polyozellin to the latter. These syntheses involved a double Suzuki-Miyaura coupling using chlorophenylboronic acid as a common key building block, and Cu mediated Ullmann cyclization as key steps. The inhibitory activities of synthetic compounds against POP and cancer cells were also evaluated.     

A monoclonal antibody against T-cell receptor αβ induces endogenous cytokines and prevents mice from a lethal infection with Listeria monocytogenes

Abstract In vivo induction of cytokines by a monoclonal antibody (mAb) against T-cell receptor (TCR) αβ and the protective effect induced by the mAb on a lethal infection with Listeria monocytogenes were studied. Injection of anti-TCR αβ mAb induced rapid production of endogenous tumour necrosis factor in the spleens, and gamma interferon and interleukin-6 in the bloodstreams and spleens of mice. Administration of anti-CD4 mAb, anti-CD8 mAb, or anti-Thy1.2 mAb resulted in suppression of anti-TCR αβ mAb-induced endogenous cytokine production. Mice were protected against lethal L. monocytogenes infection when treated with anti-TCR αβ mAb. The protective effect was not demonstrated in CD4 + cell- or CD8 + cell-depleted mice. These results suggest that anti-TCR αβ mAb shows a protective effect on a lethal infection with L. monocytogenes in mice and that the mAb-induced endogenous cytokines might be involved in the effect of anti-TCR αβ mAb.     

Ontogenetic development of neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system of the dogfish

This immunocytochemical study was carried out to elucidate the ontogenetic development of neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system of the cloudy dogfish, Scyliorhinus torazame. Immunostained cells first appeared in the pancreas of the embryo at the 15-mm stage, and were also detected in the vitellointestinal duct of the yolk stalk at the 20-mm stage. These cells were polymorphic, with occasional processes that were sometimes directed toward the vascular wall or into the cavity of the vitellointestinal duct. At the 34-mm stage, immunostained cells could also be found in the proximal part of the spiral intestine and, by the 74-mm stage, immunopositive cells were present in the gastric mucosa. In the gut and pancreas, the cells gradually increased in number with development, whereas in the vitellointestinal duct and internal yolk sac, they decreased and seemed to disappear following hatching. Thus, in juveniles, the distribution of the neuropeptide Y-like-immunoreactive cells in the gastroenteropancreatic endocrine system had attained that of adults. Electron-microscopic immunocytochemistry demonstrated that, in the labeled cells of the vitellointestinal duct, the neuropeptide Y-like antigen was located in cytoplasmic granules, as in the cells of the gut and pancreas.This paper is dedicated to Professor Yoshiharu Honma, on the occasion of his retirement and inauguration as Emeritus Professor     

Association between Psoriasis Vulgaris and Coronary Heart Disease in a Hospital-Based Population in Japan

BackgroundPsoriasis vulgaris is a chronic inflammatory skin disease with an immune-genetic background. It has been reported as an independent risk factor for coronary heart disease (CHD) in the United States and Europe. The purpose of this study was to investigate the association between psoriasis and CHD in a hospital-based population in Japan.MethodsFor 113,065 in-hospital and clinic patients at our institution between January 1, 2011 and January 1, 2013, the diagnostic International Classification of Diseases (ICD)-10 codes for CHD, hypertension, dyslipidemia, diabetes, and psoriasis vulgaris were extracted using the medical accounting system and electronic medical record, and were analyzed.ResultsThe prevalence of CHD (n = 5,167, 4.5%), hypertension (n = 16,476, 14.5%), dyslipidemia (n = 9,236, 8.1%), diabetes mellitus (n = 11,555, 10.2%), and psoriasis vulgaris (n = 1,197, 1.1%) were identified. The prevalence of CHD in patients with hypertension, dyslipidemia, diabetes, and psoriasis vulgaris were 21.3%, 22.2%, 21.1%, and 9.0%, respectively. In 1,197 psoriasis patients, those with CHD were older, more likely to be male, and had more number of the diseases surveyed by ICD-10 codes. Multivariate analysis showed that psoriasis vulgaris was an independent associated factor for CHD (adjusted odds ratio [OR]: 1.27; 95% confidence interval [CI]: 1.01–1.58; p = 0.0404) along with hypertension (adjusted OR: 7.78; 95% CI: 7.25–8.36; p < 0.0001), dyslipidemia (adjusted OR: 2.35; 95% CI: 2.19–2.52; p < 0.0001), and diabetes (adjusted OR: 2.86; 95% CI: 2.67–3.06; p < 0.0001).ConclusionPsoriasis vulgaris was independently associated with CHD in a hospital-based population in Japan.