Spatial differences and seasonal changes of net carbonate accumulation on some coral reefs of the Ryukyu Islands, Japan

This study sought to understand short-term spatial changes in accretion and erosion on (experimental) carbonate blocks on three coral reefs of the Ryukyu Islands, Japan. The principal objectives were to differentiate net accretion/erosion according to season, location, depth and substrate-type. At all locations the summer season showed more positive net weight changes and higher coralline algal coverage than the winter season. Windward reefs revealed higher net accretion and higher coralline algal coverage than leeward reefs. Massive (Holocene) Porites blocks showed highest net loss, followed by Pleistocene carbonate and (Holocene) Acropora blocks. High population densities of Echinometra mathaei (de Blainville) were recorded on reefs adjacent to large human populations and overall net carbonate loss significantly correlated to densities of E. mathaei type A.     

Facile synthesis of stable and lectin-recognizable DNA-carbohydrate conjugates via diazo coupling

Stable and lectin-recognizable DNA-carbohydrate conjugates were prepared by diazo coupling of lactose and cellobiose derivatives to fragmented salmon testes DNA. The diazo coupling is suggested to take place selectively to guanine bases since the amount of lactose moiety introduced was directly proportional to the G content of various DNAs with different G contents. According to the CD spectra, the conjugates bearing carbohydrate less than 25% content kept a typical B-type conformation similar to native DNA. The conjugates possessed higher melting temperature and stronger nuclease resistance both to exo- and endonucleases than native DNA. Gel shift assay and fluorescence binding assay showed that the DNA-lactose conjugates were specifically bound to galactose-specific lectin RCA(120) with strong binding affinity (Ka = 10(4)-10(5) M(-1)) due to glycoside cluster effect. This facile method will be a useful protocol of molecular design for cell-targeted gene therapy.     

Endurance Training-Induced Increase in Circulating Irisin Levels Is Associated with Reduction of Abdominal Visceral Fat in Middle-Aged and Older Adults

To elucidate the effects of endurance training on circulating irisin levels in young and middle-aged/older adults, and to determine the association between endurance training-induced alteration of irisin and reduction in body fat. Twenty-five healthy young (age 21 ± 1 years; 16 men, 9 women) and 28 healthy middle-aged/older adults (age 67 ± 8 years; 12 men, 16 women) participated in the study. Each age cohort was divided into two groups: the endurance-training group (14 young, 14 middle-aged/older) and the control group. Subjects in the training groups completed an 8-week endurance-training program (cycling at 60-70% peak oxygen uptake [V˙O_2peak] for 45 min, 3 days/week). Before and after the intervention, we evaluated serum irisin level, V˙O_2peak, and body composition. The increase in V˙O_2peak in the young and middle-aged/older training groups after the intervention period was significantly greater than those in the young and middle-aged/older control groups (P < 0.05). Serum irisin level was significantly increased in the middle-aged/older training group after the intervention period (P < 0.01), but not in the young training group. Furthermore, in the middle-aged/older training group, the endurance training-induced reduction in visceral adipose tissue area was negatively correlated with the change in serum irisin level (r = −0.54, P < 0.05). These results suggest a possible role for secreted irisin in the exercise-induced alteration of abdominal visceral fat in middle-aged and older adults.     

Molecular and morphological evidence for conspecificity of two common Indo-Pacific species of Palythoa (Cnidaria: Anthozoa)

Most studies characterize metacommunities based on a single snapshot of the spatial structure, which may be inadequate for taxa with high migratory behavior (e.g., fish). Here, we applied elements of metacommunity structure to examine variations in the spatial distributions of stream fishes over time and to explore possible structuring mechanisms. Although the major environmental gradients influencing species distributions remained largely the same in time, the best-fit pattern of metacommunity structure varied according to sampling occasion and whether or not we included non-native species in the analyses. Quasi-Clementsian and Clementsian structures were the predominant best-fit structures, indicating the importance of species turnover among sites and the existence of more or less discrete community boundaries. The environmental gradient most correlated with metacommunity structure was defined by altitude, area of artificial ponds in the catchment, and dissolved oxygen content. Our results suggest that the best-fit metacommunity structure of the native species can change in time in this catchment due to seasonal changes in distribution patterns. However, the distribution of non-native species throughout the landscape homogenizes the temporal variability in metacommunity structure of native species. Further studies are necessary from other regions to examine best-fit metacommunity structures of stream fishes within relatively short environmental gradients.     

Expression profiling of cumulus cells reveals functional changes during ovulation and central roles of prostaglandin EP2 receptor in cAMP signaling

To understand the role of prostaglandin (PG) receptor EP2 (Ptger2) signaling in ovulation and fertilization, we investigated time-dependent expression profiles in wild-type (WT) and Ptger2^−/− cumuli before and after ovulation by using microarrays. We prepared cumulus cells from mice just before and 3, 9 and 14 h after human chorionic gonadotropin injection. Key genes including cAMP-related and epidermal growth factor (EGF) genes, as well as extracellular matrix- (ECM-) related and chemokine genes were up-regulated in WT cumuli at 3 h and 14 h, respectively. Ptger2 deficiency differently affected the expression of many of the key genes at 3 h and 14 h. These results indicate that the gene expression profile of cumulus cells greatly differs before and after ovulation, and in each situation, PGE₂-EP2 signaling plays a critical role in cAMP-regulated gene expression in the cumulus cells under physiological conditions.     

l-Carnitine is essential to β-oxidation of quarried fatty acid from mitochondrial membrane by PLA2

Mitochondrial β-oxidation is an important system involved in the energy production of various cells. In this system, the function of l-carnitine is essential for the uptake of fatty acids to mitochondria. However, it is unclear whether or not endogenous respiration, ADP-induced O₂ consumption without substrates, is caused by l-carnitine treatment. In this study, we investigated whether l-carnitine is essential to the β-oxidation of quarried fatty acids from the mitochondrial membrane by phospholipase A₂ (PLA₂) using isolated mitochondria from the liver of rats. Intact mitochondria were incubated in a medium containing Pi, CoA and l-carnitine. The effect of l-carnitine treatment on ADP-induced mitochondrial respiration was observed without exogenous respiratory substrate. Increase in mitochondrial respiration was induced by treatment with l-carnitine in a concentration-dependent manner. Treatment with rotenone, a complex I blocker, completely inhibited ADP-induced oxygen consumption even in the presence of l-carnitine. Moreover, the l-carnitine dependent ADP-induced mitochondrial oxygen consumption did not increase when PLA₂ inhibitors were treated before ADP treatment. The l-carnitine-dependent ADP-induced oxygen consumption did contribute to ATP productions but not heat generation via an uncoupling system. These results suggest that l-carnitine might be essential to the β-oxidation of quarried fatty acids from the mitochondrial membrane by PLA₂.     

Identification of antisense RNA stem–loops that inhibit RNA–protein interactions using a bacterial reporter system

Many well-characterized examples of antisense RNAs from prokaryotic systems involve hybridization of the looped regions of stem–loop RNAs, presumably due to the high thermodynamic stability of the resulting loop–loop and loop–linear interactions. In this study, the identification of RNA stem–loops that inhibit U1A protein binding to the hpII RNA through RNA–RNA interactions was attempted using a bacterial reporter system based on phage λ N-mediated antitermination. As a result, loop sequences possessing 7–8 base complementarity to the 5′ region of the boxA element important for functional antitermination complex formation, but not the U1 hpII loop, were identified. In vitro and in vivo mutational analysis strongly suggested that the selected loop sequences were binding to the boxA region, and that the structure of the antisense stem–loop was important for optimal inhibitory activity. Next, in an attempt to demonstrate the ability to inhibit the interaction between the U1A protein and the hpII RNA, the rational design of an RNA stem–loop that inhibits U1A-binding to a modified hpII was carried out. Moderate inhibitory activity was observed, showing that it is possible to design and select antisense RNA stem–loops that disrupt various types of RNA–protein interactions.