Early development and neurogenesis of Temnopleurus reevesii

Sea urchins are model non‐chordate deuterostomes, and studying the nervous system of their embryos can aid in the understanding of the universal mechanisms of neurogenesis. However, despite the long history of sea urchin embryology research, the molecular mechanisms of their neurogenesis have not been well investigated, in part because neurons appear relatively late during embryogenesis. In this study, we used the species Temnopleurus reevesii as a new sea urchin model and investigated the detail of its development and neurogenesis during early embryogenesis. We found that the embryos of T. reevesii were tolerant of high temperatures and could be cultured successfully at 15–30°C during early embryogenesis. At 30°C, the embryos developed rapidly enough that the neurons appeared at just after 24 h. This is faster than the development of other model urchins, such as Hemicentrotus pulcherrimus or Strongylocentrotus purpuratus. In addition, the body of the embryo was highly transparent, allowing the details of the neural network to be easily captured by ordinary epifluorescent and confocal microscopy without any additional treatments. Because of its rapid development and high transparency during embryogenesis, T. reevesii may be a suitable sea urchin model for studying neurogenesis. Moreover, the males and females are easily distinguishable, and the style of early cleavages is intriguingly unusual, suggesting that this sea urchin might be a good candidate for addressing not only neurology but also cell and developmental biology.     

Determinants of Slow Walking Speed in Ambulatory Patients Undergoing Maintenance Hemodialysis

Walking ability is significantly lower in hemodialysis patients compared to healthy people. Decreased walking ability characterized by slow walking speed is associated with adverse clinical events, but determinants of decreased walking speed in hemodialysis patients are unknown. The purpose of this study was to identify factors associated with slow walking speed in ambulatory hemodialysis patients. Subjects were 122 outpatients (64 men, 58 women; mean age, 68 years) undergoing hemodialysis. Clinical characteristics including comorbidities, motor function (strength, flexibility, and balance), and maximum walking speed (MWS) were measured and compared across sex-specific tertiles of MWS. Univariate and multivariate logistic regression analyses were performed to examine whether clinical characteristics and motor function could discriminate between the lowest, middle, and highest tertiles of MWS. Significant and common factors that discriminated the lowest and highest tertiles of MWS from other categories were presence of cardiac disease (lowest: odds ratio [OR] = 3.33, 95% confidence interval [CI] = 1.26–8.83, P<0.05; highest: OR = 2.84, 95% CI = 1.18–6.84, P<0.05), leg strength (OR = 0.62, 95% CI = 0.40–0.95, P<0.05; OR = 0.57, 95% CI = 0.39–0.82, P<0.01), and standing balance (OR = 0.76, 95% CI = 0.63–0.92, P<0.01; OR = 0.81, 95% CI = 0.68–0.97, P<0.05). History of fracture (OR = 3.35, 95% CI = 1.08–10.38; P<0.05) was a significant factor only in the lowest tertile. Cardiac disease, history of fracture, decreased leg strength, and poor standing balance were independently associated with slow walking speed in ambulatory hemodialysis patients. These findings provide useful data for planning effective therapeutic regimens to prevent decreases in walking ability in ambulatory hemodialysis patients.     

Antibacterial activity of disodium succinoyl glycyrrhetinate,a derivative of glycyrrhetinic acid against Streptococcus mutans

Streptococcus mutans is a cariogenic bacterium that localizes in the oral cavity. Glycyrrhetinic acid (GRA) is a major component of licorice extract. GRA and several derivatives, including disodium succinoyl glycyrrhetinate (GR‐SU), are known to have anti‐inflammatory effects in humans. In this study, the antimicrobial effect of GRA and its derivatives against the S. mutans UA159 strain were investigated. Minimum inhibitory concentrations (MICs) of GRA and GR‐SU showed antibacterial activity against the S. mutans strain, whereas other tested derivatives did not. Because GR‐SU is more soluble than GRA, GR‐SU was used for further experiments. The antibacterial activity of GR‐SU against 100 S. mutans strains was evaluated and it was found that all strains are susceptible to GR‐SU, with MIC values below 256 µg/mL. A cell viability assay showed that GR‐SU has a bacteriostatic effect on S. mutans cells. As to growth kinetics, sub‐MICs of GR‐SU inhibited growth. The effect of GR‐SU on S. mutans virulence was then investigated. GR‐SU at sub‐MICs suppresses biofilm formation. Additionally, GR‐SU greatly suppresses the pH drop caused by the addition of glucose and glucose‐induced expression of the genes responsible for acid production (ldh and pykF) and tolerance (aguD and atpD). Additionally, expression of enolase, which is responsible for the carbohydrate phosphotransferase system, was not increased in the presence of GR‐SU, indicating that GR‐SU suppresses incorporation of sugars into S. mutans. In conclusion, GR‐SU has antibacterial activity against S. mutans and also decreases S. mutans virulence.     

Regulation of angiotensin converting enzyme activity in cultured human vascular endothelial cells

Angiotensin converting enzyme (ACE) of vascular endothelial cells is suggested to control vascular wall tonus through the conversion of angiotensin I (AI) to angiotensin II (AII) and the degradation of bradykinin. To obtain more insight into the pathophysiological significance of ACE of vascular endothelial cells, we studied the regulation of ACE produced by cultured human umbilical vein endothelial cells (EC). Phorbol 12-myristate 13-acetate (PMA) increased the cellular and medium ACE activity, accompanied by a marked morphological change in EC. N'-O'-dibutylyladenosine 3';5'-cyclic monophosphate (db-cAMP) increased only the cellular ACE activity and not the medium ACE activity. The effect of isoproterenol with 0.1mM theophylline mimicked that of db-cAMP. These findings suggest that PMA and cAMP-related agents participate in the control of vascular wall tonus through the positive regulation of ACE produced by vascular endothelial cells.     

Hopenol-b,a triterpene alcohol from Euphorbia supina

In addition to the known triterpene motiol, hopenol-b (hop-22(29)-en-3β-ol) was isolated from the whole herb of Euphorbia supina. It has not been found previously in nature, though it has been prepared by both synthetic and biosynthetic methods.     

A second method for induction of a transmissible entity in the control of cancer in mice.

Spontaneous tumour-bearing mice of the C3H/St and subline C3HB/St inbred strains received injections of three nucleosides, adenosine, 6-methyl adenosine, and 5-methyl cytidine, prepared in the same molecular concentration as they had occurred in an alcohol-soluble liver extract which in previous work had suppressed tumour growth. Two transmissible entities appear to be present and they show different degrees of effect upon the growth and regression of spontaneous tumours of mammary gland origin (adenocarcinoma). The first transmissible entity (TE) occurred in the lineal descent of mice following injection of the liver extract. The second entity (TE2) appeared following injection of 5-methyl cytidine. TE manifested its maximum effect in suppressing cancer in mice during the 20th generation of a lineal descent following the injection of the original liver extract into a mother of the cancer proband. TE2 appears to be optimal in controlling cancer in the F11 generation of a second lineal descent derived from an original cancer proband of the C3H/St inbred strain injected with 5-methyl cytidine.     

Hydrogen evolution by co-immobilized Chlorella vulgaris and Clostridium butyricum cells

Whole cells of Chlorella vulgaris and Clostridium butyricum were co-immobilized in 2% agar gel. NADP was suitable as an electron carrier. The rate of hydrogen evolution increased with increasing NADP concentration. The optimum conditions for hydrogen evolution were pH 7.0 and 37°C. The immobilized C. vulgaris-NADP-immobilized Cl. butyricum system continuously evolved hydrogen at a rate of 0.29–1.34 μmol/h per mg Chl for 6 days. On the other hand, the system without NADP evolved only a trace amount of hydrogen.