Ophirasterol, a new C31 sterol from the marine sponge Topsentia ophiraphidites

Analysis of the sterol fraction obtained from the Colombian Caribbean sponge Topsentia ophiraphidites revealed that this sponge is a rich source of C30 and C31 sterols. Among them, a new C31 sterol, named ophirasterol, was isolated, and its structure was established as (22E,24R)-24-(1-buten-2-yl)cholesta-5,22-dien-3beta-ol (1) by spectral means and comparison with synthetic C-24 epimers with known configuration. Other isolated C30 and C31 sterols were the known 24-ethyl-24-methyl-22-dehydrocholesterol (2), 24-isopropyl-22-dehydrocholesterol (3), 24-isopropylcholesterol (4), 24-ethyl-24-methylcholesterol (5), 24-isopropenyl-25-methyl-22-dehydrocholesterol (6) and 24-isopropenyl-25-methylcholesterol (7), and 24-isopropenyl-22-dehydrocholesterol (8).     

Identification of stable fly attractant compounds in vinasse,a byproduct of sugarcane–ethanol distillation

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is a worldwide pest of livestock. Recent outbreaks of stable flies in sugarcane fields in Brazil have become a serious problem for livestock producers. Larvae and pupae found inside sugarcane stems after harvesting may indicate that stable flies use these stems as potential oviposition or larval development sites. Field observations suggest that outbreaks of stable flies are associated with the vinasse and filter cake derived from biomass distillation in sugarcane ethanol production that are used as fertilizers in sugarcane fields. Adult stable flies are attracted to vinasse, which appears to present an ideal larval development site. The primary goal of the present study is to demonstrate the role of vinasse in influencing the sensory physiological and behavioural responses of stable flies, and to identify its associated volatile attractant compounds. Both laboratory and field studies showed that vinasse is extremely attractive to adult stable flies. Chemical analyses of volatiles collected revealed a wide range of carboxylic acids, alcohols, phenols and aldehydes as potential attractant compounds. These newly identified attractants could be used to develop a tool for the attractant‐baited mass trapping of stable flies in order to reduce infestations.     

Growth and photosynthetic responses to salinity of the salt-marsh shrub Atriplex portulacoides

BACKGROUND AND AIMS: Atriplex (Halimione) portulacoides is a halophytic, C(3) shrub. It is virtually confined to coastal salt marshes, where it often dominates the vegetation. The aim of this study was to investigate its growth responses to salinity and the extent to which these could be explained by photosynthetic physiology. METHODS: The responses of young plants to salinity in the range 0-700 mol m(-3) NaCl were investigated in a glasshouse experiment. The performance of plants was examined using classical growth analysis, measurements of gas exchange (infrared gas analysis), determination of chlorophyll fluorescence characteristics (modulated fluorimeter) and photosynthetic pigment concentrations; total ash, sodium, potassium and nitrogen concentrations, and relative water content were also determined. KEY RESULTS: Plants accumulated Na(+) approximately in proportion to external salinity. Salt stimulated growth up to an external concentration of 200 mol m(-3) NaCl and some growth was maintained at higher salinities. The main determinant of growth response to salinity was unit leaf rate. This was itself reflected in rates of CO(2) assimilation, which were not affected by 200 mol m(-3) but were reduced at higher salinities. Reductions in net photosynthetic rate could be accounted for largely by lower stomatal conductance and intercellular CO(2) concentration. Apart from possible effects of osmotic shock at the beginning of the experiment, salinity did not have any adverse effect on photosystem II (PSII). Neither the quantum efficiency of PSII (Phi(PSII)) nor the chlorophyll fluorescence ratio (F(v)/F(m)) were reduced by salinity, and lower mid-day values recovered by dawn. Mid-day F(v)/F(m) was in fact depressed more at low external sodium concentration, by the end of the experiment. CONCLUSIONS: The growth responses of the hygro-halophyte A. portulacoides to salinity appear largely to depend on changes in its rate of photosynthetic gas exchange. Photosynthesis appears to be limited mainly through stomatal conductance and hence intercellular CO(2) concentration, rather than by effects on PSII; moderate salinity might stimulate carboxylation capacity. This is in contrast to more extreme halophytes, for which an ability to maintain leaf area can partially offset declining rates of carbon assimilation at high salinity.     

Fuscoside E: a strong anti-inflammatory diterpene from Caribbean octocoral Eunicea fusca

The screen of 10 soft coral extracts collected from the Colombian Caribbean Sea in the TPA-induced ear edema model allowed us to identify Eunicea fusca extract among others as an interesting source of active compounds. The new diterpene, fuscoside E (1), along with the known fuscoside B (2), fuscol (3), (+)-germacrene D (4) and a mixture of six sterols (5-10), were isolated from this soft coral. Their structures were elucidated by 1D and 2D NMR spectroscopy techniques. Fuscoside E (1) absolute stereochemistry was determined by chiroptical methods. Fuscoside E (1) and B (2) showed strong anti-inflammatory in the above mentioned bioassay. Additionally, fuscoside E (1) and the sterol mixture (5-10) presented antifouling activity against bacterial strains involved in surface colonization.     

功能矫形前伸青春期大鼠下颌后浅层嚼肌细胞凋亡的研究

目的：研究功能矫形前伸大鼠下颌后浅层嚼肌细胞凋亡的变化规律,探讨功能矫形的肌肉改建机理。方法：选用50只5周龄Sprague-Dawley（SD）雄性大白鼠,随机分为实验组和对照组各25只。实验组大鼠戴自制上颌功能矫治嚣,引导下颌前伸,并打开咬合。利用RT-PCR方法检测两组大鼠浅层嚼肌Bcl-2和Bax基因表达情况,利用TUNEL方法检测浅层嚼肌细胞凋亡情况。结果：①Bcl-2和Bax基因表达随大鼠戴用矫治器时间的延长而升高,至第3周开始下降但仍高于对照组,但Bax的表达高于Bcl-2。Bax/Bcl-2比值随大鼠戴用矫治器时间的延长而升高,至第4周开始下降。②TUNEL实验结果显示浅层嚼肌细胞在戴用矫治器1天后,开始出现凋亡,随着时间延长而增加,至第3周达到顶峰,第4周开始下降。结论：①Bax/Bcl-2比值升高促进浅层嚼肌细胞凋亡。②功能矫形可引起浅层嚼肌细胞凋亡,导致肌肉的结构和功能发生适应性改建。     

Reorganization of functional networks in mild cognitive impairment

Whether the balance between integration and segregation of information in the brain is damaged in Mild Cognitive Impairment (MCI) subjects is still a matter of debate. Here we characterize the functional network architecture of MCI subjects by means of complex networks analysis. Magnetoencephalograms (MEG) time series obtained during a memory task were evaluated by synchronization likelihood (SL), to quantify the statistical dependence between MEG signals and to obtain the functional networks. Graphs from MCI subjects show an enhancement of the strength of connections, together with an increase in the outreach parameter, suggesting that memory processing in MCI subjects is associated with higher energy expenditure and a tendency toward random structure, which breaks the balance between integration and segregation. All features are reproduced by an evolutionary network model that simulates the degenerative process of a healthy functional network to that associated with MCI. Due to the high rate of conversion from MCI to Alzheimer Disease (AD), these results show that the analysis of functional networks could be an appropriate tool for the early detection of both MCI and AD.     

Microsatellite Genotyping of Plasmodium vivax Isolates from Pregnant Women in Four Malaria Endemic Countries

Plasmodium vivax is the most widely distributed human parasite and the main cause of human malaria outside the African continent. However, the knowledge about the genetic variability of P. vivax is limited when compared to the information available for P. falciparum. We present the results of a study aimed at characterizing the genetic structure of P. vivax populations obtained from pregnant women from different malaria endemic settings. Between June 2008 and October 2011 nearly 2000 pregnant women were recruited during routine antenatal care at each site and followed up until delivery. A capillary blood sample from the study participants was collected for genotyping at different time points. Seven P. vivax microsatellite markers were used for genotypic characterization on a total of 229 P. vivax isolates obtained from Brazil, Colombia, India and Papua New Guinea. In each population, the number of alleles per locus, the expected heterozygosity and the levels of multilocus linkage disequilibrium were assessed. The extent of genetic differentiation among populations was also estimated. Six microsatellite loci on 137 P. falciparum isolates from three countries were screened for comparison. The mean value of expected heterozygosity per country ranged from 0.839 to 0.874 for P. vivax and from 0.578 to 0.758 for P. falciparum. P. vivax populations were more diverse than those of P. falciparum. In some of the studied countries, the diversity of P. vivax population was very high compared to the respective level of endemicity. The level of inter-population differentiation was moderate to high in all P. vivax and P. falciparum populations studied.