Isolation and physical characterization of bovine lens crystallins.

The soluble proteins from bovine lens homogenate were separated on Sepharose CL-6B (2 X 200 cm) in 0.05 M tris-NaHSO3 pH 8.2 buffer containing 20 mM EDTA. Five sharp and defined fractions (HM alpha, alpha, beta H, beta L, gamma) were obtained. Each crystallin fraction was further purified by rechromatography on the same column. Each protein fraction was pure as judged by ultracentrifugation and SDS-gel electrophoresis. The molecular weights of the five fractions were 3.04 x 10(6), 5.83 x 10(5), 1.58 x 10(5) , 4.59 x 10(4), 2.14 x 10(4) as determined from sedimentation coefficient and intrinsic viscosity data by Scheraga-Mandelkern equation, which was in close agreement with that obtained by gel filtration. The polypeptide composition of crystallins as determined by SDS-gel electrophoresis revealed one band for high molecular weight alpha (HM alpha) and alpha, three for beta H, two for beta L and one for gamma. The gross CD patterns of crystallins were about the same in the peptide region (200 nm similar to or approximately 250 nm) with a minimum centered at about 217 nm, indicative of a beta-sheet structure in all crystallins. The [theta] values at 217 nm ranged from --1700 to --3700 degrees cm2 per decimole. The CD spectra of these crystallins in the aromatic region (250 nm similar to or approximately 300 nm) were different, reflecting the different contributions of aromatic amino acids to the tertiary structure of crystallins.     

Effects of Insulin and Streptozotocin-Induced Diabetes on Brain Norepinephrine Metabolism in Rats

Administration of insulin (2 IU/kg, i.p.) produced a significant decrease (18%) in forebrain norepinephrine and a significant increase in the major metabolite of norepinephrine, 3-methoxy-4-hydroxyphenylglycol-sulfate (MOPEG-SO4, +19%) in rats. Streptozotocin-induced diabetes produced the opposite effects, resulting in an increase in forebrain norepinephrine (+17%) and a decrease in MOPEG-SO4 (-26%). In addition, insulin increased (+143%) and diabetes decreased (-41%) the turnover rate of norepinephrine, as measured by the rate of decrease of norepinephrine following inhibition of tyrosine hydroxylase by alpha-methyl-p-tyrosine. All of these effects in diabetic rats were reversed by insulin replacement therapy. These data are discussed within the context of mood disorders characteristic of diabetic patients.     

白马雪山国家级自然保护区典型森林生态系统服务

生态系统服务是近年来生态学研究的热点领域,对关键区域生态系统服务的研究具有重要意义.云南省白马雪山国家级自然保护区地处青藏高原南延部分,拥有独特的地理位置,是生物多样性保护的热点区域.本文对该保护区森林生态系统的生物量与生产力、水源涵养、营养物质循环等3项服务的功能量进行了评估.结果表明:保护区森林总生物量2215.86×104t,生产力171.84×104t·a-1;水源涵养量11964.56×104m3;N、P、K年吸收量分别为26025.94t、2638.57t、12016.85 t.研究表明,保护区森林生态效益显著,对于维持当地以及周边地区的生态安全具有重要意义.     

Ecologically heterogeneous populations of the invasive ant Wasmannia auropunctata within its native and introduced ranges

Abstract 1. The biology of most invasive species in their native geographical areas remains largely unknown. Such studies are, however, crucial in shedding light on the ecological and evolutionary processes underlying biological invasions. 2. The present study focuses on the little fire ant Wasmannia auropunctata, a species native to Central and South America that has been widely introduced and which has become invasive throughout the tropics. We characterise and compare several ecological traits of native populations in French Guiana with those in one of its introduced ranges, New Caledonia. 3. We found ecologically heterogeneous populations of W. auropunctata coexisting in the species’ native geographical area. First, we found populations restricted to naturally perturbed areas (particularly floodplains) within the primary forest, and absent from the surrounding forest areas. These populations were characterised by low nest and worker densities. Second, we found dominant populations in recent anthropogenic areas (e.g. secondary forest or forest edge along road) characterised by high nest and worker densities, and associated with low ant species richness. The local dominance of W. auropunctata in such areas can be due to the displacement of other species (cause) or the filling‐up of empty habitats unsuitable to other ants (effect). With respect to their demographic features and ant species richness, the populations of native anthropogenic habitats were to a large extent similar to the invasive populations introduced into remote areas. 4. The results point to the need for greater research efforts to better understand the ecological and demographic features of invasive species within their native ranges.     

DDC- and 3TC-bis(SATE) Monophosphate Prodrugs Overcome Cellular Resistance Mechanisms to HIV-1 Associated with Cytidine Kinase Deficiency

Abstract

A 2,3′-dideoxycytidine (ddC)-resistant T-lymphoid cell line (MOLT-4/8^rddC²⁵⁰), in which deoxycytidine kinase (dCK) gene-expression was decreased when compared with parental cells, has been selected. Cytotoxic and antiretroviral activity of ddC and 3TC was significantly lower in MOLT-4/8^rddC²⁵⁰ than in parental MOLT-4/8 cells. ddC- and 3TC-bis(SATE)phosphotriesters completely overcame cellular resistance mechanisms and showed comparable both cytotoxic and antiretroviral activity in parental and ddC-resistant cells.     

Exercise training in childhood-onset systemic lupus erythematosus: a controlled randomized trial

Introduction

Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.

Methods

Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO₂, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).

Results

The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO₂ (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.

Conclusion

A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.

Trial registration

NCT01515163.     

Mutants impaired in vacuolar metal mobilization identify chloroplasts as a target for cadmium hypersensitivity in Arabidopsis thaliana

Cadmium (Cd) is highly toxic to plants causing growth reduction and chlorosis. It binds thiols and competes with essential transition metals. It affects major biochemical processes such as photosynthesis and the redox balance, but the connection between cadmium effects at the biochemical level and its deleterious effect on growth has seldom been established. In this study, two Cd hypersensitive mutants, cad1‐3 impaired in phytochelatin synthase (PCS1), and nramp3nramp4 impaired in release of vacuolar metal stores, have been compared. The analysis combines genetics with measurements of photosynthetic and antioxidant functions. Loss of AtNRAMP3 and AtNRAMP4 function or of PCS1 function leads to comparable Cd sensitivity. Root Cd hypersensitivities conferred by cad1‐3 and nramp3nramp4 are cumulative. The two mutants contrast in their tolerance to oxidative stress. In nramp3nramp4, the photosynthetic apparatus is severely affected by Cd, whereas it is much less affected in cad1‐3. In agreement with chloroplast being a prime target for Cd toxicity in nramp3nramp4, the Cd hypersensitivity of this mutant is alleviated in the dark. The Cd hypersensitivity of nramp3nramp4 mutant highlights the critical role of vacuolar metal stores to supply essential metals to plastids and maintain photosynthetic function under Cd and oxidative stresses.