Comparative proteomic study reveals the involvement of diurnal cycle in cell division, enlargement, and starch accumulation in developing endosperm of Oryza sativa

The development and starch accumulation of cereal endosperms rely on the sugar supply of leaves, which is subject to diurnal cycles, and the endosperm itself also experiences a light/dark switch. However, revealing how the cereal endosperm responds to diurnal input remains a major challenge. We used comparative proteomic approaches to probe diurnally affected processes in rice endosperm (Oryza sativa) 10 days after flowering under 12-h light/12-h dark. Starch granules in rice endosperm showed a growth ring structure under a normal light/dark cycle but not under constant light. Sucrose showed a high level in light and low level in dark. Two-dimensional (2-D) differential in-gel electrophoresis-based proteomic analysis revealed 101 protein spots diurnally changed and 91 identities, which were involved in diverse processes with preferred distribution in stress response, protein synthesis/destination and metabolism. Proteins involved in cell division showed high expression in light and those in cell enlargement and cell wall synthesis high in dark, while starch synthesis proteins were light-downregulated and dark-upregulated. Redox homeostasis-associated proteins showed in-phase peaks under light and dark. These data demonstrate diurnal input-regulated diverse cellular and metabolic processes in rice endosperm, and coordination among these processes is essential for development and starch accumulation with diurnal input.     

Analysis of Slow (Theta) Oscillations as a Potential Temporal Reference Frame for Information Coding in Sensory Cortices

While sensory neurons carry behaviorally relevant information in responses that often extend over hundreds of milliseconds, the key units of neural information likely consist of much shorter and temporally precise spike patterns. The mechanisms and temporal reference frames by which sensory networks partition responses into these shorter units of information remain unknown. One hypothesis holds that slow oscillations provide a network-intrinsic reference to temporally partitioned spike trains without exploiting the millisecond-precise alignment of spikes to sensory stimuli. We tested this hypothesis on neural responses recorded in visual and auditory cortices of macaque monkeys in response to natural stimuli. Comparing different schemes for response partitioning revealed that theta band oscillations provide a temporal reference that permits extracting significantly more information than can be obtained from spike counts, and sometimes almost as much information as obtained by partitioning spike trains using precisely stimulus-locked time bins. We further tested the robustness of these partitioning schemes to temporal uncertainty in the decoding process and to noise in the sensory input. This revealed that partitioning using an oscillatory reference provides greater robustness than partitioning using precisely stimulus-locked time bins. Overall, these results provide a computational proof of concept for the hypothesis that slow rhythmic network activity may serve as internal reference frame for information coding in sensory cortices and they foster the notion that slow oscillations serve as key elements for the computations underlying perception.     

Serum γ-glutamyltransferase: independent predictor of risk of diabetes, hypertension, metabolic syndrome, and coronary disease

Serum γ-glutamyltransferase (GGT) is associated with oxidative stress and hepatic steatosis. The extent to which its value in determining incident cardiometabolic risk (coronary heart disease (CHD), metabolic syndrome (MetS), hypertension and type 2 diabetes) is independent of obesity needs to be further explored in ethnicities. After appropriate exclusions, a cohort of 1,667 adults of a general population (age 52 ±11 years) was evaluated prospectively at 4 year's follow-up using partly Cox proportional hazard regressions. GGT activity was measured kinetically, and values were log-transformed for analyses. MetS was identified by Adult Treatment Panel-III criteria modified for male abdominal obesity. Median (interquartile range) GGT activity was 24.9 (17.0; 35.05) U/l in men, 17.0 (12.3; 24.0) U/l in women. In linear regression analysis, while smoking status was not associated, (male) sex, sex-dependent age, alcohol usage, BMI, fasting triglycerides and C-reactive protein (CRP) were significant independent determinants of circulating GGT. Each 1-s.d. increment in (= 0.53 ln GGT) GGT activity significantly predicted in each sex incident hypertension (hazard ratio (HR) 1.20 (95% confidence interval (CI) 1.10; 1.31)), and similarly MetS, after adjustment for age, alcohol usage, smoking status, BMI and menopause. Strongest independent association existed with diabetes (HR 1.3 (95% CI 1.1; 1.5)) whereas GGT activity tended to marginally predict CHD independent of total bilirubin but not of BMI. Higher serum total bilirubin levels were protective against CHD risk in women. We conclude that elevated serum GGT confers, additively to BMI, risk of hypertension, MetS, and type 2 diabetes but only mediates adiposity against CHD risk.     

Complete sequences of plasmids from the hemolytic-uremic syndrome-associated Escherichia coli strain HUSEC41

The complete and annotated sequences of four plasmids from a historical enteroaggregative Shiga toxin-producing Escherichia coli (HUSEC) serotype O104:H4 strain, HUSEC41/01-09591, isolated in 2001 in Germany are reported.     

Loss of B7-H1 expression by recipient parenchymal cells leads to expansion of infiltrating donor CD8+ T cells and persistence of graft-versus-host disease

Previous experimental studies have shown that acute graft-versus-host disease (GVHD) is associated with two waves of donor CD8(+) T cell expansion. In the current studies, we used in vivo bioluminescent imaging, in vivo BrdU labeling, and three different experimental GVHD systems to show that B7-H1 expression by recipient parenchymal cells controls the second wave of alloreactive donor CD8(+) T cell expansion and the associated second phase of GVHD. Loss of B7-H1 expression by parenchymal cells during the course of GVHD was associated with persistent proliferation of donor CD8(+) T cells in GVHD target tissues and continued tissue injury, whereas persistent expression of B7-H1 expression by parenchymal cells led to reduced proliferation of donor CD8(+) T cells in GVHD target tissues and resolution of GVHD. These studies demonstrate that parenchymal cell expression of B7-H1 is required for tolerizing infiltrating T cells and preventing the persistence of GVHD. Our results suggest that therapies designed to preserve or restore expression of B7-H1 expression by parenchymal tissues in the recipient could prevent or ameliorate GVHD in humans.     

Age, growth and food composition of Scorpaena porcus (Linnaeus, 1758) in the southeastern Black Sea

Samples of 525 Scorpaena porcus (Linnaeus, 1758) were collected from the southeastern Black Sea between January 2002 and May 2003 for information on age, growth, length–weight relationships and stomach contents. Total length of sampled fish ranged from 4.6 to 22.9 cm and total weight from 1.3 to 220 g. The sex ratio (1 : 1.61) was biased toward females (P < 0.05). Positive allometric growth was determined in the collected samples. The length–weight relationship for all individuals was described by the parameters a  = 0.0149 and b  = 3.09, with r ² = 0.99. The sample was composed of five age-classes (0–7 years). Three growth models were used to identify the growth characteristics: von Bertalanffy,     ; logistic,     ; and Schnute and Richards,     . Among these, the Schnute and Richards model was best fitted to the data as     The diet was composed of Carcinus mediterraneus (18.2%), Crangon crangon (12.1%), unidentified crab species (10.6%), Gobius sp. (4.6%), Palaemon sp. (4.5%), Macropipus sp. (4.5%), Engraulis encrasicholus (1.5%), Gastropoda (1.5%), and unidentified remains (34.9%).     

真菌异化硝酸盐还原机理的研究进展

真菌异化硝酸盐还原途径的发现打破了反硝化仅存在于原核细胞这一传统观念。真菌异化硝酸盐还原途径是在环境中氧供给受限的情况下发生的, 包括反硝化和氨的发酵。硝酸盐能诱导产生反硝化作用的酶, 其中, 硝酸盐还原酶与亚硝酸还原酶位于线粒体中, 它们所催化的酶促反应能偶联呼吸链ATP合成酶合成ATP, 同时产生NO。与参与反硝化作用前两个酶不同, 真菌NO还原酶能以NADH为直接电子供体将NO还原为N2O, 在NAD+的再生和自由基NO的脱毒中起着重要作用。氨发酵则将硝酸盐还原成NH4+, 同时偶联乙酸的生成和底物水平磷酸化。此文从参与该过程的关键酶、关键酶的表达调节、真菌与细菌异化硝酸盐还原的比较等角度综述了真菌异化硝酸盐还原的最新研究进展。