Modulations in key enzymes of nitrogen metabolism in two high yielding genotypes of mulberry (Morus alba L.) with differential sensitivity to salt stress

Effect of salinity stress on the performance of nitrogen metabolism was studied in two high yielding genotypes of mulberry with differential sensitivity to NaCl (S1 and ATP, salt tolerant and susceptible, respectively). Three-month-old healthy mulberry plants were subjected to different regimes of NaCl stress [0.0 (control), 0.5, 1.0 and 1.5% NaCl] and leaf samples were collected on 4, 8 and 12 DAT (days after treatment) for the analysis. The activities of nitrate reductase (NR: EC 1.6.6.1), nitrite reductase (NiR: EC 1.6.6.4), protease, glutamine synthetase (GS: EC 6.3.1.2) and its accumulation pattern, glutamate synthase (GOGAT: EC 1.4.1.13), glutamate dehydrogenase (NADH-GDH: EC 1.4.1.2 and NADPH-GDH: EC 1.4.1.4), aspartate aminotransferase (AAT: EC 2.6.1.1) and alanine aminotransferase (ALAT: EC 2.6.1.2) coupled with total protein content, free amino acid level and ammonia content were studied in leaves of both genotypes of mulberry. The total protein content in leaves of both genotypes declined with progressive accumulation of free amino acid levels. Further, the decrease in protein content was less in S1 than ATP, and it was correlated with protease activity, ammonia content and accumulation of free amino acid levels. Higher free amino acid levels were registered for S1 than ATP at 1.0 and 1.5% NaCl stress and on all days of sampling. Ammonia content was increased in both genotypes and comparatively higher ammonia levels were recorded for ATP. Increased NaCl concentrations lead to a decrease in the activity of NR and NiR in both the genotypes, the decrease was more pronounced in ATP than S1. The enhanced activity of GDH (NADH and NADPH) was noticed in both genotypes, whereas the NADPH-GDH activity was found relatively higher in S1. The immunoblot analysis with GS-45 antibodies revealed a specific cross-reaction with 42 and 45 kDa proteins in S1, and only 45 kDa protein in ATP genotype. However, increased GS protein accumulation pattern (both 42 and 45 kDa) was observed in S1 under high NaCl. Whereas, accumulation of 45 kDa protein was unchanged at all levels of stress and slight accumulation in 42 kDa protein at 1.5% NaCl was observed for ATP. Elevation in the enzyme activities of GS, GOGAT were coupled with AAT and ALAT observed in both the genotypes. Higher enzymatic activities of S1 than ATP under salinity stress may be due to efficient capacity of ammonia detoxification. Salt tolerance of S1 supports the higher metabolic activity under salinity leading to lesser amount of ammonia accumulation and higher levels of free amino acid in the tissue. In agreement with these results the physiological significance of enzymatic changes and ammonia assimilation during salt stress in relevance to plant nitrogen metabolism was discussed.     

PR3 and Elastase Alter PAR1 Signaling and Trigger vWF Release via a Calcium-Independent Mechanism from Glomerular Endothelial Cells

Neutrophil proteases, proteinase-3 (PR3) and elastase play key roles in glomerular endothelial cell (GEC) injury during glomerulonephritis. Endothelial protease-activated receptors (PARs) are potential serine protease targets in glomerulonephritis. We investigated whether PAR1/2 are required for alterations in GEC phenotype that are mediated by PR3 or elastase during active glomerulonephritis. Endothelial PARs were assessed by flow cytometry. Thrombin, trypsin and agonist peptides for PAR1 and PAR2, TFLLR-NH(2) and SLIGKV-NH(2,) respectively, were used to assess alterations in PAR activation induced by PR3 or elastase. Endothelial von Willebrand Factor (vWF)release and calcium signaling were used as PAR activation markers. Both PR3 and elastase induced endothelial vWF release, with elastase inducing the highest response. PAR1 peptide induced GEC vWF release to the same extent as PR3. However, knockdown of PARs by small interfering RNA showed that neither PAR1 nor PAR2 activation caused PR3 or elastase-mediated vWF release. Both proteases interacted with and disarmed surface GEC PAR1, but there was no detectable interaction with cellular PAR2. Neither protease induced a calcium response in GEC. Therefore, PAR signaling and serine protease-induced alterations in endothelial function modulate glomerular inflammation via parallel but independent pathways.     

生物医学工程的精要、责任和展望

作为工程学的直属分支,建立生物医学工程学科的主要目的不是为了开辟一个新的科学研究领域,而是为了借助工程学的方法来解决生物医学领域所面临的实际问题,以及借助工程师们所接受的专业训练、所拥有的专业知识、所具备的工作技巧来提高医疗服务的质量和效果。工程学与生物医学的结合已取得了一些具有里程碑性质的成果。在中低收入国家,例如中国,生物医学工程有责任保证合理使用专业技术,为低廉、可靠、有效的医疗服务提供支持。本文将根据可预见和不可预见的学科发展限制和困难,对学科发展的现实目标和责任进行严肃、冷静地讨论。     

APPLIED ISSUES: Effects of habitat rehabilitation on brown trout (Salmo trutta) in boreal forest streams

1. Degradation of stream habitat because of anthropogenic activities (e.g. channelisation) has had a dramatic impact on fluvial environments and their biota, and as a consequence, increasing effort has been directed towards the restoration of degraded rivers. However, a major problem is that the success (or failure) of restoration has been rarely tested using a well‐designed monitoring programme to allow reliable detection of an impact, if any exists. We used a spatially and temporally replicated, balanced Before‐After‐Control‐Impact design to assess the impact of stream habitat rehabilitation on the densities and growth of brown trout of three age‐classes in North Finnish forest streams. 2. Three separate sections in each of six streams were selected for the study. After 3 years of pre‐rehabilitation monitoring, two randomly selected sections in each stream were restored; one using large woody debris and boulders and the other using only boulders. A third section remained as an unmodified control. Monitoring of fish densities continued for 3 years after rehabilitation. 3. Rehabilitation clearly increased streambed complexity, but did not have detectable effects on brown trout stocks in either of the rehabilitation schemes (LWD or stones), except for age‐2+ and older fish which decreased in abundance compared to control reaches. A severe drought after rehabilitation in late summer 2002 reduced densities of trout to a low level in all streams, overriding any local effects of rehabilitation. Rehabilitation structures seemed to provide some safeguard against drought for age‐2 and older, but not for the younger age‐classes. 4. Our results add to the growing body of literature suggesting that large‐scale regional factors may overwhelm local management efforts. To be successful in the future, stream rehabilitation schemes must include drought refuge areas for fish and other stream biota.     

Occurrence of oestrogenic pollutants and widespread feminisation of male tilapia in peri-urban dams in Bulawayo,Zimbabwe

Peri-urban water bodies are at risk from excessive pollution as they are direct sinks for urban effluents. The occurrence of oestrogenic and androgenic endocrine disrupting chemicals (EDCs) in effluents and water bodies around the city of Bulawayo, Zimbabwe, and their effects on wild fish was investigated in 2013. Effluent and water were sampled from sewage treatment plants, an urban stream, and effluent-polluted dams, and were compared with a ‘pristine’ dam upstream of Bulawayo. Organic pollutants were extracted by solid-phase extraction and tested for EDCs using a yeast oestrogen/androgen screen. Oestrogenic and androgenic potencies were expressed as 17β-oestradiol equivalent (EEq) or dihydrotestosterone equivalent (TEq). Tilapia and catfish from the dams were analysed for gonado-somatic indices and testis histopathology. Effluents from STPs, which directly flow into Umguza Dam, had EEq of 33 ng l^?1 and 55 ng l^?1, respectively. Umguza Dam, Khami Dam and Matsheumhlope Stream had EEqs of 237 ng l^–1, 9 ng l^?1 and 2 ng l^?1, respectively. Androgenic activity was detected in only one STP (TEq = 93 ng l^?1). Tilapia sampled from effluent-polluted dams had high incidences of testis-ova, but catfish had no signs of reproductive dysfunction. These findings underscore the need for greater attention to EDCs in developing countries where there is scant literature regarding their occurrence and impacts.     

Flow based anomaly intrusion detection system using ensemble classifier with Feature Impact Scale

Cluster Computing - The exponential growth of services in the internet with rapid development of technologies results produces huge growth in the traffic, which maximizes the possibility of...