Salt stress effects on the photosynthetic electron transport chain in two chickpea lines differing in their salt stress tolerance

The main objective of this study was to evaluate the effects of salt stress on the photosynthetic electron transport chain using two chickpea lines (Cicer arietinum L.) differing in their salt stress tolerance at the germination stage (AKN 87 and AKN 290). Two weeks after sowing, seedlings were exposed to salt stress for 2 weeks and irrigated with 200 ml of 200 mM NaCl every 2 days. The polyphasic OJIP fluorescence transient and the 820-nm transmission kinetics (photosystem I) were used to evaluate the effects of salt stress on the functionality of the photosynthetic electron transport chain. It was observed that a signature for salt stress was a combination of a higher J step (V_J), a smaller IP amplitude, and little or no effect on the primary quantum yield of PSII (φ_Po). We observed for AKN 290 a shorter leaf life cycle, which may represent a mechanism to cope with salt stress. For severely salt-stressed leaves, an inhibition of electron flow between the PQ pool and P700 was found. The data also suggest that the properties of electron flow beyond PSI are affected by salt stress.     

A Peroxisomal Disorder of Severe Intellectual Disability,Epilepsy, and Cataracts Due to Fatty Acyl-CoA Reductase 1 Deficiency

Rhizomelic chondrodysplasia punctata (RCDP) is a group of disorders with overlapping clinical features including rhizomelia, chondrodysplasia punctata, coronal clefts, cervical dysplasia, congenital cataracts, profound postnatal growth retardation, severe intellectual disability, and seizures. Mutations in PEX7, GNPAT, and AGPS, all involved in the plasmalogen-biosynthesis pathway, have been described in individuals with RCDP. Here, we report the identification of mutations in another gene in plasmalogen biosynthesis, fatty acyl-CoA reductase 1 (FAR1), in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity. Exome analyses revealed a homozygous in-frame indel mutation (c.495_507delinsT [p.Glu165_Pro169delinsAsp]) in two siblings from a consanguineous family and compound-heterozygous mutations (c.[787C>T];[1094A>G], p.[Arg263^∗];[Asp365Gly]) in a third unrelated individual. FAR1 reduces fatty acids to their respective fatty alcohols for the plasmalogen-biosynthesis pathway. To assess the pathogenicity of the identified mutations, we transfected human embryonic kidney 293 cells with plasmids encoding FAR1 with either wild-type or mutated constructs and extracted the lipids from the cells. We screened the lipids with gas chromatography and mass spectrometry and found that all three mutations abolished the reductase activity of FAR1, given that no fatty alcohols could be detected. We also observed reduced plasmalogens in red blood cells in one individual to a range similar to that seen in individuals with RCDP, further supporting abolished FAR1 activity. We thus expand the spectrum of clinical features associated with defects in plasmalogen biosynthesis to include FAR1 deficiency as a cause of syndromic severe intellectual disability with cataracts, epilepsy, and growth retardation but without rhizomelia.     

Photodimerizations of hydroxy- and benzoylated 4-azachalcones and quantum chemical investigation of the reactions

Photodimerization reactions of compounds 4–6 gave four new cyclobutane-containing compounds (7–9) with full control over the stereochemistry at the four stereogenic centers. These new cyclobutane-containing compounds had β-truxinic (7a), δ-truxinic (7b and 9), and ε-truxillic (8) structures. However, o-, m-, and p-hydroxy 4-azachalcones (1–3) did not give photochemical cyclization products under any conditions (in solvent or in their solid or molten states). Experimental data suggested the possibility of frontier orbital control over stereochemical behavior, so some theoretical calculations were performed. Full geometrical optimization of compounds 1–9 was performed via DFT B3LYP/6-31⁺G**, and their electronic structures were also investigated. The geometries of the singlet and triplet states were initially optimized by density functional theory (DFT) and the configuration interaction singles (CIS) B3LYP/3-21⁺G** level. An additional calculation was performed for the triplet state using the ground-state geometry. The possible photochemical dimerization products of compounds 7–9 (a–g) and the intrinsic reaction coordinates (IRCs) of the reactions of compounds 4–6 were calculated theoretically by the DFT/3-21⁺G** method. The configurations (reactant, transition state, product, and reaction pathway) corresponding to the stationary points (minima or saddle points) were determined. The intrinsic reaction coordinates were followed to verify the energy profiles that connect each TS to the appropriate local minimum. The dimeric products expected from the calculations coincided with the dimers produced experimentally.     

High performance liquid chromatography analysis of 2-mercaptoethylamine (cysteamine) in biological samples by derivatization with N-(1-pyrenyl) maleimide (NPM) using fluorescence detection

2-Mercaptoethylamine (cysteamine) is an aminothiol compound used as a drug for the treatment of cystinosis, an autosomal recessive lysosomal storage disorder. Because of cysteamine's important role in clinical settings, its analysis by sensitive techniques has become pivotal. Unfortunately, the available methods are either complex or labor intensive. Therefore, we have developed a new rapid, sensitive, and simple method for determining cysteamine in biological samples (brain, kidney, liver, and plasma), using N-(1-pyrenyl) maleimide (NPM) as the derivatizing agent and reversed-phase high performance liquid chromatography (HPLC) with a fluorescence detection method (lambda(ex)=330 nm, lambda(em)=376 nm). The mobile phase was acetonitrile and water (70:30) with acetic acid and o-phosphoric acid (1 mL/L). The calibration curve for cysteamine in serine borate buffer (SBB) was found to be linear over a range of 0-1200 nM (r(2)=0.9993), and in plasma and liver matrix, the r(2) values were 0.9968 and 0.9965, respectively. The coefficients of the variation for the within-run and between-run precisions ranged from 0.68 to 9.90% and 0.63 to 4.17%, respectively. The percentage of relative recovery ranged from 94.1 to 98.6%.     

Mosaicism for the Charcot-Marie-Tooth disease type 1A duplication suggests somatic reversion

A female patient with clinical signs and symptoms of a demyelinating neuropathy was shown to have a duplication of the 1.5-Mb region on chromosome 17p11.2, typical of the great majority of cases of Charcot-Marie-Tooth disease type 1A (CMT1A). However, analysis of DNA extracted from peripheral blood revealed a 2:2.4 instead of the usual 2:3 ratio between the 7.8- and 6.0-kb EcoRI fragments in the proximal and distal repetitive extragenic palindromic (REP) elements of CMT1A. Detection of a 3.2-kb EcoRI/SacI kb junction fragment with probe pLR7.8 confirmed the CMT1A duplication. The dosage of this junction fragment, compared with a 2.8-kb EcoRI/SacI fragment of the proximal REP elements of CMT1A, was 2:0.58 instead of the expected 2:1 dosage for heterozygous CMT1A duplications. We hypothesized that the lower dosages of these restriction fragments specific for the CMT1A duplication were due to mosaicism; this was confirmed by fluorescence in situ hybridization analysis with the D17S122-specific probe pVAW409R1. In peripheral blood lymphocytes the percentage of interphase nuclei with a duplication in 17p11.2 was 49%. In interphase nuclei extracted from buccal mucosa, hair-root cells or paraffin-embedded nervous tissue the duplication was detectable in 51%, 66% and 74%, respectively. This is the first report of mosaicism in a patient with a CMT1A duplication identified by three different and independent techniques. Received: 14 November 1995 / Revised: 13 February 1996     

The using of Gammarus pulex as a biomonitor in ecological risk assessment of secondary effluent from municipal wastewater treatment plant in Tunceli,Turkey

The objectives of this research are the assessment of secondary effluents (SEs) quality by evaluating chemical parameters and biomarkers. For this purpose, MDA and GSH levels were determined by spectrofotometer. SOD, CAT, and GP_X activities were determined by using ELISA kit in the groups of control and the groups exposed to SE. The level of MDA and the activities of SOD in Gammarus pulex vary depending on the exposure time. GSH levels and GSH-P_X activities increased in G. pulex exposed to the effluent compared to the control during 24 h and 96 h. CAT activities were in SE group were found lower than the control in G. pulex during 24 h and 96 h. Current experimental results show that SOD, CAT, GP_X activities, and GSH and MDA levels in G. pulex are sensitive and appropriate responses for assess the effects of anthropogenic contaminants on the aquatic ecosystems, particularly effluent complex mixtures.