14-3-3 proteins double the number of outward-rectifying K+ channels available for activation in tomato cells

Outward-rectifying K+ channels are modulated in response to environmental stimuli by a range of intracellular factors, such as cytoplasmic Ca2+, pH, kinases and phosphatases. Here we report that voltage-dependent outward-rectifying K+ channels in tomato cells are also targets for modulation by 14-3-3 proteins. In whole-cell patch-clamp experiments, recombinant 14-3-3 protein (tomato isoform TFT7) was introduced into tomato cell protoplasts via the patch pipette. As a result the steady-state outward K+ current increased twofold and this increase was not dependent upon the presence of cytoplasmic ATP. A phosphorylated peptide that contained a phosphorylated 14-3-3 target-binding motif (RSTS*TP), derived from nitrate reductase, blocked the effect of 14-3-3, thus showing the specific nature of 14-3-3 action. Kinetic parameters of the conductance, like (de)activation kinetics, voltage dependence of gating and activation potential, were not significantly different between control and 14-3-3 infused cells. Analysis of single-channel activity and whole-cell noise indicated that the single-channel conductance was not affected by 14-3-3 infusion. We conclude that 14-3-3 proteins recruit 'sleepy' channels into a voltage-activatable state. The molecular mechanism underlying the 1 : 1 ratio of constitutively active and 14-3-3 recruited channels is discussed in the light of known functions of 14-3-3 dimers.     

First-trimester hemoglobin A1 and risk for major malformation and spontaneous abortion in diabetic pregnancy

The relationship between the level of hemoglobin A1 (Hb A1) in the first trimester and major malformations and spontaneous abortions was examined in 303 insulin-requiring diabetic gravidas. During the study period, all patients with insulin-requiring diabetes mellitus antedating pregnancy who registered for prenatal care prior to 12 weeks' gestation and who had a known outcome were included. Thirty-five percent of the patients entered with a first-trimester Hb A1 of greater than 11.0% of total hemoglobin (9 standard deviations above the mean for a nondiabetic population). A broad spectrum of glycemic control was therefore represented. The risk of spontaneous abortion was 12.4% with first-trimester Hb A1 less than or equal to 9.3% and 37.5% with Hb A1 greater than 14.4% (risk ratio 3.0; 95% confidence interval 1.3-7.0). The risk for major malformation was 3.0% with Hb A1 less than or equal to 9.3% and 40% with Hb A1 greater than 14.4% (risk ratio 13.2; 95% confidence interval 4.3-40.4). Although the risks for both adverse outcomes were markedly elevated following a first trimester in very poor metabolic control, there was a broad range of control over which the risks were not substantially elevated. To keep malformations and spontaneous abortions to a minimum among diabetic women does not require "excellent" control; there seems to be a fairly broad range of "acceptable" control.     

Longitudinal proxy measurements in multiple sclerosis: patient-proxy agreement on the impact of MS on daily life over a period of two years

Background  

The use of self-report measurements in clinical settings is increasing. However, in patients with limitations that interfere with reliable self-assessment such as cognitive impairment or mood disturbances, as may be the case in multiple sclerosis (MS), data collection might be problematic. In these situations, information obtained from proxy respondents (e.g. partners) may replace self-ratings. The aim of this study was to examine the value of proxy ratings at separate points in time and to assess patient-proxy agreement on possible changes in disease impact of MS.     

Ectopic AtCBF1 over-expression enhances freezing tolerance and induces cold acclimation-associated physiological modifications in potato

We studied the effect of ectopic AtCBF over-expression on physiological alterations that occur during cold exposure in frost-sensitive Solanum tuberosum and frost-tolerant Solanum commersonii . Relative to wild-type plants, ectopic AtCBF1 over-expression induced expression of COR genes without a cold stimulus in both species, and imparted a significant freezing tolerance gain in both species: 2 °C in S. tuberosum and up to 4 °C in S. commersonii . Transgenic S. commersonii displayed improved cold acclimation potential, whereas transgenic S. tuberosum was still incapable of cold acclimation. During cold treatment, leaves of wild-type S. commersonii showed significant thickening resulting from palisade cell lengthening and intercellular space enlargement, whereas those of S. tuberosum did not. Ectopic AtCBF1 activity induced these same leaf alterations in the absence of cold in both species. In transgenic S. commersonii , AtCBF1 activity also mimicked cold treatment by increasing proline and total sugar contents in the absence of cold. Relative to wild type, transgenic S. commersonii leaves were darker green, had higher chlorophyll and lower anthocyanin levels, greater stomatal numbers, and displayed greater photosynthetic capacity, suggesting higher productivity potential. These results suggest an endogenous CBF pathway is involved in many of the structural, biochemical and physiological alterations associated with cold acclimation in these Solanum species.     

Benthic freshwater nematode community dynamics under conditions of Tilapia aquaculture in Egypt

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices.     

Melanin in the extracellular matrix of germlings of Botrytis cinerea

Previous work on the composition of the extracellular matrix of germlings of the plant pathogenic fungus Botrytis cinerea demonstrated the presence of carbohydrate, protein, and simple lipids; which, together, comprised 50-60% of the dry weight. Here we show that most of the remaining mass of the extracellular matrix consists of a chemically inert dark pigment with the electron paramagnetic resonance characteristics of a melanin. Scanning electron micrographs of the purified pigment, and transmission electron micrographs of thin sections made using the pigment indicate that it has a filamentous structure. We conclude that melanin is an important component of the extracellular matrix of germlings of B. cinerea. This is the first report of a melanin present in the extracellular matrix of a plant pathogenic fungus.     

ACUTE EFFECTS OF MOVEMENT VELOCITY ON BLOOD LACTATE AND GROWTH HORMONE RESPONSES AFTER ECCENTRIC BENCH PRESS EXERCISE IN RESISTANCE-TRAINED MEN

This study aimed to compare the effects of different velocities of eccentric muscle actions on acute blood lactate and serum growth hormone (GH) concentrations following free weight bench press exercises performed by resistance-trained men. Sixteen healthy men were divided into two groups: slow eccentric velocity (SEV; n = 8) and fast eccentric velocity (FEV; n = 8). Both groups performed four sets of eight eccentric repetitions at an intensity of 70% of their one repetition maximum eccentric (1RMecc) test, with 2-minute rest intervals between sets. The eccentric velocity was controlled to 3 seconds per range of motion for SEV and 0.5 seconds for the FEV group. There was a significant difference (P < 0.001) in the kinetics of blood lactate removal (at 3, 6, 9, 15, and 20 min) and higher mean values for peak blood lactate (P = 0.001) for the SEV group (9.1 ± 0.5 mM) compared to the FEV group (6.1 ± 0.4 mM). Additionally, serum GH concentrations were significantly higher (P < 0.001) at 15 minutes after bench press exercise in the SEV group (1.7 ± 0.6 ng · mL⁻¹) relative to the FEV group (0.1 ± 0.0 ng · mL⁻¹). In conclusion, the velocity of eccentric muscle action influences acute responses following bench press exercises performed by resistance-trained men using a slow velocity resulting in a greater metabolic stress and hormone response.     

Different prion disease phenotypes result from inoculation of cattle with two temporally separated sources of sheep scrapie from Great Britain

Background

Given the theoretical proposal that bovine spongiform encephalopathy (BSE) could have originated from sheep scrapie, this study investigated the pathogenicity for cattle, by intracerebral (i.c.) inoculation, of two pools of scrapie agents sourced in Great Britain before and during the BSE epidemic. Two groups of ten cattle were each inoculated with pools of brain material from sheep scrapie cases collected prior to 1975 and after 1990. Control groups comprised five cattle inoculated with sheep brain free from scrapie, five cattle inoculated with saline, and for comparison with BSE, naturally infected cattle and cattle i.c. inoculated with BSE brainstem homogenate from a parallel study. Phenotypic characterisation of the disease forms transmitted to cattle was conducted by morphological, immunohistochemical, biochemical and biological methods.

Results

Disease occurred in 16 cattle, nine inoculated with the pre-1975 inoculum and seven inoculated with the post-1990 inoculum, with four cattle still alive at 83 months post challenge (as at June 2006). The different inocula produced predominantly two different disease phenotypes as determined by histopathological, immunohistochemical and Western immunoblotting methods and biological characterisation on transmission to mice, neither of which was identical to BSE. Whilst the disease presentation was uniform in all scrapie-affected cattle of the pre-1975 group, the post-1990 inoculum produced a more variable disease, with two animals sharing immunohistochemical and molecular profile characteristics with animals in the pre-1975 group.

Conclusion

The study has demonstrated that cattle inoculated with different pooled scrapie sources can develop different prion disease phenotypes, which were not consistent with the phenotype of BSE of cattle and whose isolates did not have the strain typing characteristics of the BSE agent on transmission to mice.     

Acute insulin secretion as a predictor of weight gain in healthy humans

Objective: We sought to determine the role of the acute insulin secretory response to glucose (AIRg) in predicting weight gain in normoglycemic persons with no family history of diabetes, who are at low risk for development of disease. Research Methods and Procedures: One hundred five individuals (64 men and 41 women) who underwent measures of weight and AIRg and insulin sensitivity index (S_I) by intravenous glucose tolerance test between 1963 and 1983 were surveyed again for weight between 1994 and 1999, with a mean follow‐up of 26 ± 4 years. Results: Mean change in weight was 8 ± 10 kg. Annualized weight change was calculated as change in kilograms divided by change in year and averaged 0.27 ± 0.04 kg/yr. Dividing the cohort by either median AIRg or median S_I demonstrated no association of either AIRg or S_I with total or annualized weight gain. Subgroup analysis by ideal body weight or gender did not alter the association. Furthermore, no association between AIRg and weight gain rate was seen within insulin‐sensitive or ‐resistant subgroups, although younger age at entry was associated with greater rates of weight gain. Discussion: Our data suggest that neither AIRg nor S_I plays a role in predicting weight gain in normoglycemic individuals with no family history of diabetes.     

Protein structure analysis of mutations causing inheritable diseases. An e-Science approach with life scientist friendly interfaces

Background  

Many newly detected point mutations are located in protein-coding regions of the human genome. Knowledge of their effects on the protein's 3D structure provides insight into the protein's mechanism, can aid the design of further experiments, and eventually can lead to the development of new medicines and diagnostic tools.