Structural properties of a scaled gecko foot-hair

Experimental measurements on a cm-scale replica structure of a gecko foot-hair where magnets are used in place of (the usual) van der Waals force are reported. We conduct naked-eye experiments and investigate the mechanical properties of such hair structure and shapes that constitute it. Links between shapes and mechanical properties (functions) useful in geckos for clinging onto walls and adhering to rough surfaces are explained in terms of energy efficiency.     

Comparative analysis of a 229-kb medaka genomic region, containing the zic1 and zic4 genes, with Fugu, human, and mouse

Medaka is one of the prominent model animals, which also include other fishes such as Fugu and zebrafish. Its genome is relatively compact but has not been well characterized. Here we have sequenced a 229-kb region of medaka, containing the Double anal fin (Da) locus, and compared its structure to those in Fugu, human, and mouse. This region, representing a gene-poor region, contains no major rearrangements and can be readily compared among different species. Comparison of G+C contents and repeats suggested that medaka and Fugu are highly related as expected and that medaka is more similar to mammals than Fugu is. Sequence comparisons of developmental genes zic1 and zic4, identified within this region, revealed that zic1, but not zic4, is highly conserved among vertebrates. The 5' coding region of zic4 is, however, extremely homologous among fishes with little synonymous substitutions, implying its distinct function in fish.     

Salt-inducible multidrug efflux pump protein in the moderately halophilic bacterium Chromohalobacter sp

It has been known that halophilic bacteria often show natural resistance to antibiotics, dyes, and toxic metal ions, but the mechanism and regulation of this resistance have remained unexplained. We have addressed this question by identifying the gene responsible for multidrug resistance. A spontaneous ofloxacin-resistant mutant derived from the moderately halophilic bacterium Chromohalobacter sp. strain 160 showed a two- to fourfold increased resistance to structurally diverse compounds, such as tetracycline, cefsulodin, chloramphenicol, and ethidium bromide (EtBr), and tolerance to organic solvents, e.g., hexane and heptane. The mutant produced an elevated level of the 58-kDa outer membrane protein. This mutant (160R) accumulated about one-third the level of EtBr that the parent cells did. An uncoupler, carbonyl cyanide m-chlorophenylhydrazone, caused a severalfold increase in the intracellular accumulation of EtBr, with the wild-type and mutant cells accumulating nearly equal amounts. The hrdC gene encoding the 58-kDa outer membrane protein has been cloned. Disruption of this gene rendered the cells hypersusceptible to antibiotics and EtBr and led to a high level of accumulation of intracellular EtBr. The primary structure of HrdC has a weak similarity to that of Escherichia coli TolC. Interestingly, both drug resistance and the expression of HrdC were markedly increased in the presence of a high salt concentration in the growth medium, but this was not observed in hrdC-disrupted cells. These results indicate that HrdC is the outer membrane component of the putative efflux pump assembly and that it plays a major role in the observed induction of drug resistance by salt in this bacterium.     

Cloning and embryonic expression of six wnt genes in the medaka (Oryzias latipes) with special reference to expression of wnt5a in the pectoral fin buds

WNTs are secreted signaling molecules which control cell differentiation and proliferation. They are known to play essential roles in various developmental processes. Wnt genes have been identified in a variety of animals, and it has been shown that their amino acid sequences are highly conserved throughout evolution. To investigate the role of wnt genes during fish development from the evolutionary viewpoint, six medaka wnt genes (wnt4, wnt5a, wnt6, wnt7b, wnt8b and wnt8-like) were isolated and their embryonic expression was examined. These wnt genes were expressed in various tissues during embryonic development, and most of their expression patterns were conserved or comparable to those of other vertebrates. Thus, these wnt genes may be useful as molecular markers to investigate development and organogenesis using the medaka. Focus was on wnt5a, which was expressed in the pectoral fin buds, because its expression pattern was particularly comparable to that in tetrapod limbs. Its detailed expression pattern was further examined during pectoral fin bud development. The conservation and diversification of Wnt5a expression through the evolutionary transition from fish fins to tetrapod limbs is discussed.     

Negative regulation of platelet clearance and of the macrophage phagocytic response by the transmembrane glycoprotein SHPS-1

SHPS-1 is a receptor-type glycoprotein that binds and activates the protein-tyrosine phosphatases SHP-1 and SHP-2, and thereby negatively modulates intracellular signaling initiated by various cell surface receptors coupled to tyrosine kinases. SHPS-1 also regulates intercellular communication in the neural and immune systems through its association with CD47 (integrin-associated protein) on adjacent cells. Furthermore, recent studies with fibroblasts derived from mice expressing an SHPS-1 mutant that lacks most of the cytoplasmic region suggested that the intact protein contributes to cytoskeletal function. Mice homozygous for this SHPS-1 mutation have now been shown to manifest thrombocytopenia. These animals did not exhibit a defect in megakaryocytopoiesis or in platelet production. However, platelets were cleared from the bloodstream more rapidly in the mutant mice than in wild-type animals. Furthermore, peritoneal macrophages from the mutant mice phagocytosed red blood cells more effectively than did those from wild-type mice; in addition, they exhibited an increase both in the rate of cell spreading and in the formation of filopodia-like structures at the cell periphery. These results indicate that SHPS-1 both contributes to the survival of circulating platelets and down-regulates the macrophage phagocytic response.     

Rapid Screening of a Novel Arrayed Medaka (Oryzias latipes) Cosmid Library

Medaka (Oryzias latipes) has many advantages for genetic and developmental studies. With recent advances in the genome analyses of other species, rapid accumulation of resources for medaka genomics is expected. In this study, we generated an arrayed medaka cosmid library from the HNI inbred strain, carrying a 40-kb insert on average. The library consists of approximately 120,000 clones with a 6-fold genomic coverage. Cosmid clones can be screened within 2 days using standard polymerase chain reaction. Considering the advantage of the cosmid insert size and the compact genome size of the medaka, this library provides a powerful tool for future genome analyses.     

Distinct Roles of Urinary Liver-Type Fatty Acid-Binding Protein in Non-Diabetic Patients with Anemia

BackgroundVarious stresses including ischemia are known to up-regulate renal L-FABP gene expression and increase the urinary excretion of L-FABP. In diabetic patients with anemia, the urinary excretion of L-FABP is significantly increased. We studied the clinical significance of urinary L-FABP and its relationship with anemia in non-diabetic patients.ResultsUrinary L-FABP levels were significantly higher in patients with anemia compared to those in patients without anemia. Similarly, the urinary L-FABP levels were significantly higher in patients with albuminuria compared to those in patients without albuminuria. Urinary L-FABP levels correlated with urinary albumin-to-creatinine ratios, estimated glomerular filtration rates, body mass index, and hemoglobin levels. Multivariate linear regression analysis determined that hemoglobin levels (β = -0.249, P = 0.001) and urinary albumin-to-creatinine ratios (β = 0.349, P < 0.001) were significant predictors of urinary L-FABP levels.ConclusionsUrinary L-FABP is strongly associated with anemia in non-diabetic patients.     

Extracellular Matrix and Growth Factors Improve the Efficacy of Intramuscular Islet Transplantation

BackgroundThe efficacy of intramuscular islet transplantation is poor despite being technically simple, safe, and associated with reduced rates of severe complications. We evaluated the efficacy of combined treatment with extracellular matrix (ECM) and growth factors in intramuscular islet transplantation.MethodsMale BALB/C mice were used for the in vitro and transplantation studies. The following three groups were evaluated: islets without treatment (islets-only group), islets embedded in ECM with growth factors (Matrigel group), and islets embedded in ECM without growth factors [growth factor-reduced (GFR) Matrigel group]. The viability and insulin-releasing function of islets cultured for 96 h were significantly improved in Matrigel and GFR Matrigel groups compared with the islets-only group.ResultsBlood glucose and serum insulin levels immediately following transplantation were significantly improved in the Matrigel and GFR Matrigel groups and remained significantly improved in the Matrigel group at postoperative day (POD) 28. On histological examination, significantly decreased numbers of TdT-mediated deoxyuridine triphosphate-biotin nick end labeling-positive islet cells and significantly increased numbers of Ki67-positive cells were observed in the Matrigel and GFR Matrigel groups at POD 3. Peri-islet revascularization was most prominent in the Matrigel group at POD 14.ConclusionsThe efficacy of intramuscular islet transplantation was improved by combination treatment with ECM and growth factors through the inhibition of apoptosis, increased proliferation of islet cells, and promotion of revascularization.     

Pharmacokinetics,Safety and Tolerability of Melissa officinalis Extract which Contained Rosmarinic Acid in Healthy Individuals: A Randomized Controlled Trial

The aim of this study was to evaluate the safety, tolerability and pharmacokinetics of single dose of Melissa officinalis extract which contained rosmarinic acid, including food-effects in healthy individuals. A total of eleven healthy individuals were randomly assigned to treatment arms in the two studies [Study 1 (fasted state) and Study 2 (fed state)]. Rosmarinic acid in serum was measured by a coulometric detection method using High-Performance Liquid Chromatography electrochemical detector. The serum concentration of total rosmarinic acid peaked at 1 hour after administration of Melissa officinalis extract containing 500mg rosmarinic acid in fasted state, with a maximum serum concentration 162.20 nmol/ L. The area under the curve for intact rosmarinic acid was calculated from the serum concentration-time profile to be 832.13 nmol • hour/ L. Food intake increases area under the curve and delayed time at which the maximum serum concentration. Rosmarinic acid supplementation did not affect liver, kidney, or blood cell function parameters. No adverse event was reported by any of the participants due to the study treatment. Single dose of Melissa officinalis extract containing 500 mg rosmarinic acid appears to be safe and tolerable in healthy individuals. Food intake increased the exposure of rosmarinic acid and delayed absorption of rosmarinic acid in healthy individuals.

Trial Registration

Trial Registration: UMIN-CTR UMIN000004997