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1.
Cadmium (200 ppm) applied through the rooting medium to 30-day-old wheat plants decreased chlorophyll content, net CO2 exchanges and PSII activity by 34, 54 and 43% respectively. Thylakoid total lipids, total glycolipids, total phospholipids and total neutral lipids decreased by 22, 23, 12 and 25%, respectively, under cadmium treatment. Thylakoid membrane glycolipids had three major constituents, viz. monogalactosyl diacylglycerol, digalactosyl diacylglycerol and sulphoquinovosyl diacylglycerol. Monogalactosyl diacylglycerol and digalactosyl diacylglycerol contents decreased by 32 and 27%, respectively, under cadmium. Cadmium application also decreased the concentration of phosphatidyl glycerol and phosphatidyl choline to the extent of about 57 and 31%, respectively. On the other hand, phosphatidic acid and free fatty acids content showed an increase. These compositional changes in thylakoid membranes might be responsible for reduced PSII activity and rate of photosynthesis as observed under cadmium treatment. 相似文献
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3.
Sucheta S Kulkarni Vidur Sabharwal Seema Sheoran Atrayee Basu Kunihiro Matsumoto Naoki Hisamoto Anindya Ghosh-Roy Sandhya P Koushika 《Genetics》2021,219(3)
Neuronal regeneration after injury depends on the intrinsic growth potential of neurons. Our study shows that UNC-16, a Caenorhabditis elegans JIP3 homolog, inhibits axonal regeneration by regulating initiation and rate of regrowth. This occurs through the inhibition of the regeneration-promoting activity of the long isoform of DLK-1 and independently of the inhibitory short isoform of DLK-1. We show that UNC-16 promotes DLK-1 punctate localization in a concentration-dependent manner limiting the availability of the long isoform of DLK-1 at the cut site, minutes after injury. UNC-16 negatively regulates actin dynamics through DLK-1 and microtubule dynamics partially via DLK-1. We show that post-injury cytoskeletal dynamics in unc-16 mutants are also partially dependent on CEBP-1. The faster regeneration seen in unc-16 mutants does not lead to functional recovery. Our data suggest that the inhibitory control by UNC-16 and the short isoform of DLK-1 balances the intrinsic growth-promoting function of the long isoform of DLK-1 in vivo. We propose a model where UNC-16’s inhibitory role in regeneration occurs through both a tight temporal and spatial control of DLK-1 and cytoskeletal dynamics. 相似文献
4.
The abundance and inherent potential for variations in simple sequence repeats (SSRs) or microsatellites resulted in valuable source for genetic markers in
eukaryotes. We describe the organization and abundance of SSRs in fungus Fusarium graminearum (causative agent for Fusarium head blight or head
scab of wheat). We identified 1705 SSRs of various nucleotide repeat motifs in the sequence database of F. graminearum. It is observed that
mononucleotide repeats (62%) were most abundant followed by di- (20%) and trinucleotide repeats (14%). It is noted that tetra-, penta- and
hexanucleotide repeats accounted for only 4% of SSRs. The estimated frequency of Class I SSRs (perfect repeats ≥20 nucleotides) was one SSR per 124.5
kb, whereas the frequency of Class II (perfect repeats >10 nucleotides and ≫20 nucleotides) was one SSR per 25.6 kb. The dynamics of SSRs will be a
powerful tool for taxonomic, phylogenetic, genome mapping and population genetic studies as SSR based markers show high levels of allelic variation,
codominant inheritance and ease of analysis. 相似文献
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6.
S. K. Bishnoi B. Kumar C. Rani K. S. Datta P. Kumari I. S. Sheoran R. Angrish 《Biologia Plantarum》2006,50(1):135-137
Two pigeonpea [Cajanus cajan (L.) Millsp.] genotypes, a salt tolerant Manak and a salt sensitive ICPL 88039 were subjected to stress treatment of 3 mM
boron, 60 mM NaCl and boron + NaCl at the seedling stage. Radicle and plumule proteins were analyzed by SDS-PAGE. Boron treatment
increased 28.3 kDa proteins in plumule and 38.3 and 51.9 kDa proteins in radicle of Manak, however, there was no specific
protein in ICPL 88039 either in plumule or in radicle. In NaCl treatment 95.6 kDa proteins appeared in plumule and 67.5 kDa
proteins in radicle of Manak. Conversely content of some proteins decreased by boron treatment alone or in combination with
NaCl although they were present in the controls. Thus, 54.3 kDa protein disappeared in ICPL 88039 plumule, 68.4 kDa in Manak
radicle and 28.1 kDa in ICPL 88039 radicle. 相似文献
7.
The activation of D-tyrosine by tyrosyl-tRNA synthetase has been investigated using single and multiple turnover kinetic methods. In the presence of saturating concentrations of D-tyrosine, the activation reaction displays sigmoidal kinetics with respect to ATP concentration under single turnover conditions. In contrast, when the kinetics for the activation reaction are monitored using a steady-state (multiple turnover) pyrophosphate exchange assay, Michaelis-Menten kinetics are observed. Previous investigations indicated that activation of l-tyrosine by the K233A variant of Bacillus stearothermophilus tyrosyl-tRNA synthetase displays sigmoidal kinetics similar to those observed for activation of d-tyrosine by the wild-type enzyme. Kinetic analyses indicate that the sigmoidal behavior of the d-tyrosine activation reaction is not enhanced when Lys-233 is replaced by alanine. This supports the hypothesis that the mechanistic basis for the sigmoidal behavior is the same for both d-tyrosine activation by wild-type tyrosyl-tRNA synthetase and activation of l-tyrosine by the K233A variant. The observed sigmoidal behavior presents a paradox, as tyrosyl-tRNA synthetase displays an extreme form of negative cooperativity, known as "half-of-the-sites reactivity," with respect to tyrosine binding and tyrosyl-adenylate formation. We propose that the binding of D-tyrosine weakens the affinity with which ATP binds to the functional subunit in tyrosyl-tRNA synthetase. This allows ATP to bind initially to the nonfunctional subunit, inducing a conformational change in the enzyme that enhances the affinity of the functional subunit for ATP. The observation that sigmoidal kinetics are observed only under single turnover conditions suggests that this conformational change is stable over multiple rounds of catalysis. 相似文献
8.
Proteome analysis of embryo and endosperm tissues from germinating tomato seed was conducted using 1-DE, 2-DE, and MS. Mobilization of the most abundant proteins, which showed similar profiles in the two tissues, occurred first in the endosperm. CBB R-250 staining of 2-DE gels revealed 352 and 369 major protein spots in the embryo and endosperm, respectively, at 0 h. Of these, 75 major spots were selected, excised, in-gel digested with trypsin, and analyzed by MALDI-TOF-MS and/or LC-ESI-Q/TOF-MS/MS. Peptide MS and MS/MS data were searched against publicly available protein and EST databases, and 47 proteins identified. Embryo-specific proteins included a BAC19.13 homologue, whereas four proteins specific to the endosperm were tomato mosaic virus coat proteins related to defense mechanisms. The most abundant proteins both in the embryo and endosperm were seed storage proteins, i.e., legumins (11 spots), vicilins (11 spots), albumin (2 spots). Housekeeping enzymes, actin-binding profilin, defense-related protein kinases, nonspecific lipid transfer protein, and proteins involved in general metabolism were also identified. The roles of some of the proteins identified in the embryo and endosperm are discussed in relation to seed germination in tomato. 相似文献
9.
Sohal JS Singh SV Subodh S Sheoran N Narayanasamy K Singh PK Singh AV Maitra A 《Microbiological research》2009,164(3):330-337
Effective control of paratuberculosis and investigations of potential link to Crohn's disease have been hampered by the lack of effective assays for easy and accurate diagnosis of Mycobacterium avium subspecies paratuberculosis (Map). Map is extremely fastidious and depends on iron chelator (Mycobactin). Map strains from humans and sheep are very difficult to isolate and may require years to emerge. Therefore, small numbers of Map isolates have been maintained in available collections. This situation has limited the study of biodiversity of Map. Though, much is known about environmental and host factors that contribute to paratuberculosis disease, but little is known about bacterial genetic mechanism of infection. Diagnostic and strain typing markers still demand improvements. Complete genome sequence of Map K10 strain is available in public domain for comparative genomics with other mycobacteria and clinical isolates of Map. It is anticipated that the genome sequence will help in carrying molecular diagnosis and strain typing with respect to Map forward at rapid pace. This paper reviews the current diagnostic and strain typing markers, which may be useful in typing of clinical isolates in near future. 相似文献
10.
Sean A. Dalrymple John Ko Inder Sheoran Susan G. W. Kaminskyj David A. R. Sanders 《PloS one》2013,8(10)
The frequency of invasive fungal infections has rapidly increased in recent years. Current clinical treatments are experiencing decreased potency due to severe host toxicity and the emergence of fungal drug resistance. As such, new targets and their corresponding synthetic pathways need to be explored for drug development purposes. In this context, galactofuranose residues, which are employed in fungal cell wall construction, but are notably absent in animals, represent an appealing target. Herein we present the structural and biochemical characterization of UDP-galactose-4-epimerase from Aspergillus nidulans which produces the precursor UDP-galactopyranose required for galactofuranose synthesis. Examination of the structural model revealed both NAD+ and UDP-glucopyranose were bound within the active site cleft in a near identical fashion to that found in the Human epimerase. Mutational studies on the conserved catalytic motif support a similar mechanism to that established for the Human counterpart is likely operational within the A. nidulans epimerase. While the K
m and k
cat for the enzyme were determined to be 0.11 mM and 12.8 s-1, respectively, a single point mutation, namely L320C, activated the enzyme towards larger N-acetylated substrates. Docking studies designed to probe active site affinity corroborate the experimentally determined activity profiles and support the kinetic inhibition results. 相似文献