Trypanothione synthetase, a validated drug target, synthesizes trypanothione from glutathione and spermidine. Here we report the gene cloning, expression, characterization and inhibition studies of trypanothione synthetase from Leishmania donovani (LdTryS). The purified recombinant LdTryS enzyme obeyed Michaelis-Menten kinetics. High substrate inhibition was observed with glutathione (K(m)=33.24 μm, k(cat)=1.3 s(-1), K(i)=866 μm). The enzyme shows simple hyperbolic kinetics with fixed glutathione concentration and with other substrates limiting K(m) values for Mg. ATP and spermidine of 14.2 μm and 139.6 μm, respectively. LdTryS was also screened for inhibitors. Tomatine, conessine, uvaol and betulin were identified as inhibitors of the enzyme and were tested for leishmanicidal activity. Finally, the effect of LdTryS inhibitors on redox homeostasis of the parasite gives a broader picture of their action against leishmaniasis. 相似文献
A survey of farmers' fields in the Savanna zone of Nigeria in 1999 indicated the presence of stalk and cob rots of maize at incidence rates of 15?–?43% and disease severity of 2.0?–?6.7. The causal organism was identified as Stenocarpella maydis (?=?Diplodia maydis). S. maydis was found to reduce seed germination by up to 29.2%. Laboratory and screen house experiments were used to evaluate the efficacy of six seed treatment fungicides indicated that Luxan (a local fungicide of unknown composition), benomyl (Benlate) and mancozeb (Dithane M-45) were more effective than metalaxyl?+?carboxin?+?furathiocarp (Apron-plus), carbendazin?+?maneb (Delsene M) and tetramethylthiuram disulphide?+?hexachlorobenzene (thiram?+?HCB) in controlling S. maydis. Stalk rot severity increased with increasing fertilization rates. 相似文献
Fusarium wilt and root-knot are important diseases of tomato. The use of chemical is becoming less appealing because of the health implications. Also, the chemicals required are often not within the reach of farmers in most of the developing part of the world. This research is aimed at finding an alternative mode of control. Tomato variety Roma VF inoculated with Meloidogyne and Fusarium were treated with 2 g/kg soil neem seed powder in the screenhouse and 2 Mg ha ? 1 in the field. An untreated and Furadan treated plot in the field served as control. Neem seed powder significantly reduced the disease severity of Fusarium and root-knot in both screenhouse and field. Results suggest the possible use of neem seed powder for control of the root-knot nematodes - Fusarium wilt disease complex. 相似文献
International Journal of Peptide Research and Therapeutics - Zika is one of the most dreaded viruses which has left mankind crippled for over years. Current no vaccines for Zika are available in... 相似文献
Context: Genotoxicity assays are widely employed in human biomonitoring studies to assess genetic damage inflicted by genotoxic agents.
Objective: Evaluation of micronuclei (MN) as a screening marker of occupational ionizing radiation (IR) exposure.
Materials and methods: Using micronucleus test, peripheral blood lymphocytes (PBL) of 402 control and exposed subjects were screened for genetic damage.
Results: The mean frequencies of micronucleus test parameters were significantly higher in exposed persons. Increase of micronucleus yield with duration of exposure (DOE) by 0.303MN/year was revealed.
Discussion and conclusion: The obtained data encourage us to consider MN as valuable markers for preventive medical screening of occupationally exposed groups. 相似文献
18S ribosomal RNA genes are the most widely used nuclear sequences for
phylogeny reconstruction at higher taxonomic levels in plants. However, due
to a conservative rate of evolution, 18S rDNA alone sometimes provides too
few phylogenetically informative characters to resolve relationships
adequately. Previous studies using partial sequences have suggested the
potential of 26S or large-subunit (LSU) rDNA for phylogeny retrieval at
taxonomic levels comparable to those investigated with 18S rDNA. Here we
explore the patterns of molecular evolution of entire 26S rDNA sequences
and their impact on phylogeny retrieval. We present a protocol for PCR
amplification and sequencing of entire (approximately 3.4 kb) 26S rDNA
sequences as single amplicons, as well as primers that can be used for
amplification and sequencing. These primers proved useful in angiosperms
and Gnetales and likely have broader applicability. With these protocols
and primers, entire 26S rDNA sequences were generated for a diverse array
of 15 seed plants, including basal eudicots, monocots, and higher eudicots,
plus two representatives of Gnetales. Comparisons of sequence dissimilarity
indicate that expansion segments (or divergence domains) evolve 6.4 to 10.2
times as fast as conserved core regions of 26S rDNA sequences in plants.
Additional comparisons indicate that 26S rDNA evolves 1.6 to 2.2 times as
fast as and provides 3.3 times as many phylogenetically informative
characters as 18S rDNA; compared to the chloroplast gene rbcL, 26S rDNA
evolves at 0.44 to 1.0 times its rate and provides 2.0 times as many
phylogenetically informative characters. Expansion segment sequences
analyzed here evolve 1.2 to 3.0 times faster than rbcL, providing 1.5 times
the number of informative characters. Plant expansion segments have a
pattern of evolution distinct from that found in animals, exhibiting less
cryptic sequence simplicity, a lower frequency of insertion and deletion,
and greater phylogenetic potential.
相似文献
Identification of novel drug targets and their inhibitors is a major challenge in the field of drug designing and development.
Diaminopimelic acid (DAP) pathway is a unique lysine biosynthetic pathway present in bacteria, however absent in mammals.
This pathway is vital for bacteria due to its critical role in cell wall biosynthesis. One of the essential enzymes of this
pathway is dihydrodipicolinate synthase (DHDPS), considered to be crucial for the bacterial survival. In view of its importance,
the development and prediction of potent inhibitors against DHDPS may be valuable to design effective drugs against bacteria,
in general. 相似文献