Elucidating growth and biochemical characteristics of rice seedlings under stress from chromium VI salt and nanoparticles.

Plants are usually provoked by a variety of heavy metal (HM) stressors that have adverse effects on their growth and other biochemical characterizations. Among the HMs, chromium has been considered the most toxic for both plants and animals. The present study was conducted to compare the phytotoxic effects of increasing chromium (VI) salt and nanoparticles (NPs) concentrations on various growth indexes of rice (Oryza sativa L. var. swat 1) seedlings grown in a hydroponic system. The 7-day rice seedlings were exposed to Cr (VI) salt and NPs hydroponic suspensions which were adjusted to the concentration of 0, 50, 100, 150, 200 and 250 mg/L. Both the Cr (VI) salt and NPs with lower concentrations (up to 100mg/L) exerted minimum inhibitory effects on the growth performance of rice seedlings. However, a significant decrease in shoot and root length and their fresh and dry weight was recorded at higher doses of Cr (VI) salt (200 mg/L) and NPs (250 mg/L). The stress induced by Cr (VI) salt has drastically affected the roots, whereas, Cr (VI) NPs significantly affected the shoot tissues. Photosynthetic pigments decreased significantly in a dose-dependent manner, and the reduction was more pronounced in rice seedlings exposed to Cr (VI) NPs compared to Cr (VI) salt. Cr (VI) NPs enhanced the membrane permeability in shoots and roots as compared to that of Cr (VI) salt, which resulted in higher concentration of reactive oxygen species (ROS) and increased lipid peroxidation. The activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) increased significantly in shoot/root tissue following exposure to higher doses of Cr (VI) salt (200 mg/L) and NPs stress (250 mg/L), while minor changes in CAT and APX activities were observed in root and shoot tissues after exposure to higher concentration of Cr (VI) NP. Furthermore, the increasing concentrations of Cr (VI) NPs increased the length of stomatal guard cells. Conclusively, Cr (VI) salt and NPs in higher concentrations have higher potential to damage the growth and induce oxidative stress in rice plants.

Genomic Insight into Differentiation and Selection Sweeps in the Improvement of Upland Cotton.

Upland cotton is the most economically important fibre crop. The human-mediated selection has resulted in modern upland cultivars with higher yield and better fibre quality. However, changes in genome structure resulted from human-mediated selection are poorly understood. Comparative population genomics offers us tools to dissect the genetic history of domestication and helps to understand the genome-wide effects of human-mediated selection. Hereby, we report a comprehensive assessment of Gossypium hirsutum landraces, obsolete cultivars and modern cultivars based on high throughput genome-wide sequencing of the core set of genotypes. As a result of the genome-wide scan, we identified 93 differential regions and 311 selection sweeps associated with domestication and improvement. Furthermore, we performed genome-wide association studies to identify traits associated with the differential regions and selection sweeps. Our study provides a genetic basis to understand the domestication process in Chinese cotton cultivars. It also provides a comprehensive insight into changes in genome structure due to selection and improvement during the last century. We also identified multiple genome-wide associations (GWAS associations) for fibre yield, quality and other morphological characteristics.

A founder RDH5 splice site mutation leads to retinitis punctata albescens in two inbred Pakistani kindreds.

Background: Retinitis punctate albescens (RPA) is a rare form of retinal dystrophy characterized by congenital stationary night blindness and a characteristic fundus appearance. Missense or nonsense mutations in RDH5 in homozygous or heterozygous state have been implicated in RPA.Material and methods: Two consanguineous Pakistani kindreds with the highly variable manifestation of RPA were studied. Whole-exome sequencing was applied to the index subjects in both families. Sanger sequencing of the candidate RDH5 variant was carried out. Pathogenicity of the detected variant was assessed through bioinformatics tools.Results: The ophthalmic examination through full-field electroretinogram of affected patients in both families was consistent with RPA. A novel splice donor variant at the first exon/intron boundary of RDH5 (NM_002905.3: c.-33 + 2dup) segregated in recessive fashion with the clinical phenotype in both families. One of the heterozygous variant carriers was also observed to have a milder expression of retinal flecks. Haplotype analysis surrounding the splice variant and pattern of runs of homozygosity were suggestive of common ancestry in these families.Conclusion: This is the first report of any pathogenic splice variant at first exon/intron boundary implicated in RPA and suggests another mechanism through which RDH5 variants could be associated with eye phenotype. This study also highlights the importance of a thorough phenotypic evaluation of heterozygous mutation carriers who may exhibit milder symptoms.

Chlorpyrifos and lambda cyhalothrin-induced oxidative stress in human erythrocytes.

Pesticides are one of the most potentially harmful chemicals introduced into the environment, and their adverse impacts on non-target organisms can be significant. The present study was conducted to shed light on effects of locally used insecticides chlorpyrifos (CPF) and lambda cyhalothrin (LCT) on oxidative stress biomarkers in human erythrocytes. The activity of catalase (CAT), superoxide dismutase (SOD), and protein contents as well as the levels of malondialdehyde (MDA) and osmotic fragility (OF) were measured in human erythrocytes exposed to CPF at concentrations of 0, 100, 500, 1000, and 2000 ppm and LCT at concentrations of 0, 100, 300, 600, and 800 ppm for 1 h and 3 h at 37°C. MDA levels and OF of erythrocytes were significantly higher in erythrocytes incubated with CPF and LCT at increasing concentrations of both insecticides and increased incubation time. However, erythrocyte CAT and SOD activities were decreased at all concentrations of CPF and LCT tested. Protein oxidation products were decreased at lower doses of CPF (100 and 500 ppm); at higher doses (1000 and 2000 ppm), total protein content was increased compared with control. In contrast LCT was associated with decreased in protein contents at all the concentrations. These results clearly demonstrated that CPF and LCT can induce oxidative stress in human erythrocytes ( in vitro).

In vitro cadmium-induced alterations in growth and oxidative metabolism of upland cotton (Gossypium hirsutum L.).

Cadmium (Cd) is a toxic pollutant, which cause both dose- and time-dependent physiological and biochemical alterations in plants. The present in vitro study was undertaken to explore Cd-induced physiological and biochemical changes in cotton callus culture at 0, 550, 700, 850, and 1000 µM Cd for four different stress periods (7, 14, 21, and 28 days). At 1000 µM Cd, mean growth values were lower than their respective control. The cell protein contents decreased only after 7-day and 14-day stress treatment. At 550 µM Cd, malondialdehyde (MDA) contents decreased after various stress periods except 21-day period. Superoxide dismutase (SOD) activity at 1000 µM Cd improved relative to its respective controls in the first three stress regimes. Almost a decreasing trend in the hydrogen peroxide (H2O2) and peroxidase (POD) activities at all Cd levels after different stress periods was noticed. Ascorbate peroxidase (APX) activity descended over its relevant controls in the first three stress regimes except at 700 µM Cd after 14- and 21-day stress duration. Moreover, catalase (CAT) mean values significantly increased as a whole. From this experiment, it can be concluded that lipid peroxidation as well as reactive oxygen species (ROS) production was relatively higher as has been revealed by higher MDA contents and greater SOD, CAT activities.