Abscisic Acid-Induced Membrane Potential Changes in Barley Aleurone Protoplasts: a Possible Relevance for the Regulation of rab Gene Expression

The effect of ABA on the membrane potential of barley (Hordeumvulgare cv. Himalaya) aleurone protoplasts was studied by measuringthe distribution of the lipophilic cation tetraphenylphosphonium(TPP⁺). The resting membrane potential (E_m) according to ourmeasurements with TPP⁺ is about –53 mV and is in agreementwith membrane potential values as measured with intracellularmicroelectrodes (about –55 mV). The TPP⁺-measurementscould demonstrate a clear dependence of the resting E_m on theexternal pH (pH_e). Stimulation of the protoplasts with ABA induced a transienthyperpolarization of the membrane to –62 mV as measuredwith TPP⁺. The hyperpolarization was ABA-concentration dependent. Inhibition of the H⁺-ATPases with the specific proton pump inhibitorsdiethylstilbestrol (DES) or Micanozole effectively preventedhyperpolarization. This indicates that the hyperpolarizationis consistent with the activation of plasma membrane H⁺-ATPases.The K⁺-inward rectifier inhibitor BaCl₂ was able to prolongthe hyperpolarization. This result suggests that the hyperpolarizationcauses the opening of K⁺-channels. The ABA-induced proton-pump activation may be involved in ABA-inducedgene-expression, as DES was able to inhibit this gene expression.BaCl₂ did only show a slight inhibitory effect on ABA-inducedgene-expression. (Received January 4, 1994; Accepted April 12, 1994)     

甘南黄河流域4种典型林分土壤C、N、P化学计量特征

土壤碳（C）、氮（N）、磷（P）是参与植物光合作用和影响生态系统初级生产力的主要元素。甘南高原是黄河流域重要的生态屏障,为了解该区不同林分土壤养分状况的差异,选取该区4种典型林分：云杉林、华北落叶松林、巴山冷杉林以及岷江冷杉糙皮桦混交林为研究对象,研究土壤C、N、P化学计量特征。结果表明：（1）岷江冷杉及糙皮桦混交林土壤C、N含量最高,云杉林土壤N、P含量最低。不同林分间P含量差异显著（P<0.05）,不同土层间C、N含量差异均显著（P<0.05）。（2）云杉林土壤C ： N值显著高于其他林分,岷江冷杉及糙皮桦混交林土壤N ： P及C ： P高于其他林分。（3）海拔、土壤pH、容重与土壤含水量是影响土壤养分的重要因素。土壤C含量与N、P含量均显著相关（P<0.05）。总体来说,不同林分土壤化学计量特征具有显著差异,混交林土壤养分状况较纯林好,未来森林管理和植被建设中,可以通过选择合适的树种和提高树种多样性有效改善森林土壤质量。     

Leucine‐rich repeat receptor‐like kinase II phylogenetics reveals five main clades throughout the plant kingdom

Receptor‐like kinases (RLKs) represent the largest group of cell surface receptors in plants. The monophyletic leucine‐rich repeat (LRR)‐RLK subfamily II is considered to contain the somatic embryogenesis receptor kinases (SERKs) and NSP‐interacting kinases known to be involved in developmental processes and cellular immunity in plants. There are only a few published studies on the phylogenetics of LRR‐RLKII; unfortunately these suffer from poor taxon/gene sampling. Hence, it is not clear how many and what main clades this family contains, let alone what structure–function relationships exist. We used 1342 protein sequences annotated as ‘SERK’ and ‘SERK‐like’ plus related sequences in order to estimate phylogeny within the LRR‐RLKII clade, using the nematode protein kinase Pelle as an outgroup. We reconstruct five main clades (LRR‐RLKII 1–5), in each of which the main pattern of land plant relationships re‐occurs, confirming previous hypotheses that duplication events happened in this gene subfamily prior to divergence among land plant lineages. We show that domain structures and intron–exon boundaries within the five clades are well conserved in evolution. Furthermore, phylogenetic patterns based on the separate LRR and kinase parts of LRR‐RLKs are incongruent: whereas the LRR part supports a LRR‐RLKII 2/3 sister group relationship, the kinase part supports clades 1/2. We infer that the kinase part includes few ‘radical’ amino acid changes compared with the LRR part. Finally, our results confirm that amino acids involved in each LRR‐RLKII–receptor complex interaction are located at N‐capping residues, and that the short amino acid motifs of this interaction domain are highly conserved throughout evolution within the five LRR‐RLKII clades.     

鼠李糖乳杆菌LV108及其发酵乳免疫调节作用的比较

目的探讨鼠李糖乳杆菌LV108及其发酵乳对免疫抑制小鼠免疫功能的调节作用。方法将BALB/c小鼠随机分为5组,每组10只,即空白组(正常小鼠)、模型组(免疫抑制小鼠)、药物组(免疫抑制小鼠食物中添加左旋咪唑)、LV108菌悬液组(免疫抑制小鼠食物中添加LV108菌悬液)和LV108发酵乳组(免疫抑制小鼠食物中添加LV108发酵乳),除空白组外其余组构建免疫抑制小鼠模型。干预4周后,分别测定各组小鼠体质量和脏器指数,血清中白细胞介素2(IL2)、肿瘤坏死因子α(TNFα)和免疫球蛋白G(IgG)含量,血清溶血素含量、耳肿胀度和肝、脾巨噬细胞吞噬能力。结果相比模型组,LV108菌悬液组和LV108发酵乳组小鼠体质量增长速度、脏器指数、血清IL2与IgG水平、血清溶血值、耳肿胀度和巨噬细胞吞噬能力显著升高(均P<0.05);在脾脏指数、血清IL2与TNFα水平、血清溶血素含量和耳肿胀度免疫指标上,LV108菌悬液组与LV108发酵乳组之间比较差异具有统计学意义(均P<0.05)。结论LV108菌体及发酵乳对免疫抑制小鼠具备较全面的免疫调节作用,均可提高小鼠的自身免疫力;LV108发酵乳对小鼠的免疫调节作用强于LV108菌体。     

Physiological Response of Adipocytes to Weight Loss and Maintenance

Background

Metabolic processes in adipose tissue are dysregulated in obese subjects and, in response to weight loss, either normalize or change in favor of weight regain.

Objective

To determine changes in adipocyte glucose and fatty acid metabolism in relation to changes in adipocyte size during weight loss and maintenance.

Methods

Twenty-eight healthy subjects (12 males), age 20–50 y, and BMI 28–35 kg/m², followed a very low energy diet for 2 months, followed by a 10-month period of weight maintenance. Body weight, body composition (deuterium dilution and BodPod), protein levels (Western blot) and adipocyte size were assessed prior to and after weight loss and after the 10-month follow-up.

Results

A 10% weight loss resulted in a 16% decrease in adipocyte size. A marker for glycolysis decreased (AldoC) during weight loss in association with adipocyte shrinking, and remained decreased during follow-up in association with weight maintenance. A marker for fatty acid transport increased (FABP4) during weight loss and remained increased during follow-up. Markers for mitochondrial beta-oxidation (HADHsc) and lipolysis (ATGL) were only increased after the 10-month follow-up. During weight loss HADHsc and ATGL were coordinately regulated, which became weaker during follow-up due to adipocyte size-related changes in HADHsc expression. AldoC was the major denominator of adipocyte size and body weight, whereas changes in ATGL during weight loss contributed to body weight during follow-up. Upregulation of ATGL and HADHsc occured in the absence of a negative energy balance and was triggered by adipocyte shrinkage or indicated preadipocyte differentiation.

Conclusion

Markers for adipocyte glucose and fatty acid metabolism are changed in response to weight loss in line with normalization from a dysregulated obese status to an improved metabolic status.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01015508","term_id":"NCT01015508"}}NCT01015508     

Phylogenetics of Stelis and closely related genera (Orchidaceae: Pleurothallidinae)

Stelis, one of the largest genera within Pleurothallidinae, was recently recircumscribed to include a few hundred more species, most of which had previously been assigned to Pleurothallis. Here, a new phylogenetic analysis of Stelis and closely related genera based on DNA sequences from nuclear ITS and chloroplast matK, based on a much larger sample, is presented; it includes more than 100 species assigned to Stelis and covers all proposed groupings within the genus, many of which have not previously been represented. Clades are proposed to enable easier discussion of groups of closely related species; each clade is characterized morphologically, ecologically, and geographically to explain the evidence found in the molecular analysis. Discussion of the evolutionary trends of character states found in the genus in its broad sense is given. The current taxonomy of the group is given and the possible taxonomical implications of the findings presented here are discussed.     

Impact of the papillary muscles on cardiac magnetic resonance image analysis of important left ventricular parameters in hypertrophic cardiomyopathy

Purpose

The use of cardiac magnetic resonance (CMR) analysis has increased in patients with hypertrophic cardiomyopathy (HCM). Quantification of left ventricular (LV) measures will be affected by the inclusion or exclusion of the papillary muscles as part of the LV mass, but the magnitude of effect and potential consequences are unknown.

Methods

We performed Cine-CMR in (1) clinical HCM patients (n?=?55) and (2) subclinical HCM mutation carriers without hypertrophy (n?=?14). Absolute and relative differences in LV ejection fraction (EF) and mass were assessed between algorithms with and without inclusion of the papillary muscles.

Results

Papillary muscle mass in group 1 was 6.6?±?2.5 g/m² and inclusion of the papillary muscles resulted in significant relative increases in LVEF of 4.5?±?1.8?% and in LV mass of 8.7?±?2.6?%. For group 2 these figures were 4.0?±?0.9 g/m², 3.8?±?1.0?% and 9.5?±?1.8?%, respectively. With a coefficient of variation of 4?%, this 9?% difference in LV mass during CMR follow-up will be considered a change, while in fact the exact same mass may have been assessed according to two different algorithms.

Conclusions

In clinical HCM patients, CMR quantification of important LV measures is significantly affected by inclusion or exclusion of the papillary muscles. In relative terms, the difference was similar in subjects without hypertrophy. This underscores a general need for a uniform approach in CMR image analysis.

     

Augmented Reticular Thalamic Bursting and Seizures in Scn1a-Dravet Syndrome

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