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91.
This protocol describes a detailed procedure for the synthesis of N-succinimidyl 4-guanidinomethyl-3-[*I]iodobenzoate ([*I]SGMIB), an agent useful in the radio-iodination of proteins, including monoclonal Abs, and peptides that undergo internalization after receptor or antigen binding. In this procedure, the tin precursor N-succinimidyl 4-[N1,N2-bis(tert-butyloxycarbonyl)guanidinomethyl]-3-(trimethylstannyl)benzoate (Boc-SGMTB, 3) was first radio-iodinated to [*I]Boc-SGMIB, a derivative of [*I]SGMIB with the guanidine function protected with Boc groups. Treatment of [*I]Boc-SGMIB with trifluoroacetic acid delivered the final product. The total time for the synthesis and purification of [*I]Boc-SGMIB and its subsequent de-protection is approximately 140 min. 相似文献
92.
Summary 2,4-Dinitrophenol and paranitrophenol are two major soil pollutants which are known to be metabolized by different soil microbes.
Relative phytotoxicities of these parent compounds and their metabolic transformation products to the growth of cucumber seedlings
were assessed. It was evident that such microbial transformations widely occurring in the soil are effective detoxification
reactions and are beneficial for the plants. 相似文献
93.
Mutuswamy Shanmugaprakash Vaidyanathan Vinoth Kumar Manickavassham Hemalatha Vargese Melbia Pothiyappan Karthik 《Engineering in Life Science》2011,11(3):322-325
Aspergillus niger produced high levels of naringinase using easily available, inexpensive industrial waste residues such as rice bran, wheat bran, sugar cane bagasse, citrus peel, and press mud in solid‐state fermentation (SSF). Among these, rice bran was found to be the best substrate. Naringinase production was highest after 96 h of incubation at 27°C and at a substrate‐to‐moisture ratio of 1:1 w/v. Supplementation of the medium with 10% naringin caused maximum induction. An inoculum age of 72 h and an inoculum level of 15% resulted in maximum production of naringinase. Enzyme production was stimulated by the addition of nutrients such as naringin and peptone. Thus, A. niger produced a very high level of naringinase within a short time in solid‐state fermentation using inexpensive agro‐residues, a level that is much higher than reported for any other microbes. 相似文献
94.
95.
U Arunachalam V Massey C S Vaidyanathan 《The Journal of biological chemistry》1992,267(36):25848-25855
p-Hydroxyphenylacetate-3-hydroxylase, an inducible enzyme isolated from the soil bacterium Pseudomonas putida, catalyzes the conversion of p-hydroxyphenylacetate to 3,4-dihydroxyphenylacetate. The enzyme requires two protein components: a flavoprotein and a colorless protein referred to as the coupling protein. The flavoprotein alone in the presence of p-hydroxyphenylacetate and substrate analogs catalyzes the wasteful oxidation of NADH with the stoichiometric generation of H2O2. A 1:1 complex of the flavoprotein and coupling protein is required for stoichiometric product formation. Such complex formation also eliminates the nonproductive NADH oxidase activity of the flavoprotein. A new assay measuring the product formation activity of the enzyme was developed using homoprotocatechuate-2,3-dioxygenase, as monitoring the oxidation of NADH was not sufficient to demonstrate enzyme activity. The coupling protein does not seem to have any redox center in it. Thus, this 2-component flavin hydroxylase resembles the other aromatic hydroxylases in that the only redox chromophore present is FAD. 相似文献
96.
VB Srinivasan M Venkataramaiah A Mondal V Vaidyanathan T Govil G Rajamohan 《PloS one》2012,7(7):e41505
Background
The diffusion of antibiotics through the outer membrane is primarily affected by the porin super family, changes contribute to antibiotic resistance. Recently we demonstrated that the CpxAR two-component signaling system alters the expression of an uncharacterized porin OmpCKP, to mediate antimicrobial resistance in K. pneumoniae.Principal Findings
In this study, functional characterization of the putative porin OmpCKP (denoted kpnO) with respect to antimicrobial susceptibility and virulence was evaluated by generating an isogenic mutant, ΔkpnO in a clinical isolate of K. pneumoniae. Estimation of uronic acid content confirmed that ΔkpnO produced ∼2.0 fold lesser capsular polysaccharide than the wild-type. The ΔkpnO displayed higher sensitivity to hyper osmotic and bile conditions. Disruption of kpnO increased the susceptibility of K. pneumoniae to oxidative and nitrostative stress by ∼1.6 fold and >7 fold respectively. The loss of the Klebsiella porin led to an increase in the minimum inhibitory concentration of tetracycline (3-fold), nalidixic acid (4-fold), tobramycin (4-fold), streptomycin (10-fold), and spectinomycin (10-fold), which could be restored following complementation. The single deletion of kpnO reduced the survival of the pathogen by 50% when exposed to disinfectants. In Caenorhabditis elegans model, the kpnO mutant exhibited significantly (P<0.01) lower virulence. To dissect the role of PhoBR signaling system in regulating the expression of the kpnO, a phoB KP isogenic mutant was constructed. The phoB KP mutant exhibited impaired gastrointestinal stress response and decreased antimicrobial susceptibility. The mRNA levels of kpnO were found to be 4-fold less in phoB KP mutant compared to wild type. A regulatory role of PhoBKP for the expression of kpnO was further supported by the specific binding of PhoBKP to the putative promoter of kpnO.Conclusions and Significance
Loss of PhoBR regulated porin KpnO resulted in increased antimicrobial resistance, increased susceptibility to gastrointestinal stress, and reduced virulence in K. pneumoniae NTUH-K2044. 相似文献97.
The advent of next generation sequencing (NGS) technologies have revolutionised the way biologists produce, analyse and interpret data. Although NGS platforms provide a cost-effective way to discover genome-wide variants from a single experiment, variants discovered by NGS need follow up validation due to the high error rates associated with various sequencing chemistries. Recently, whole exome sequencing has been proposed as an affordable option compared to whole genome runs but it still requires follow up validation of all the novel exomic variants. Customarily, a consensus approach is used to overcome the systematic errors inherent to the sequencing technology, alignment and post alignment variant detection algorithms. However, the aforementioned approach warrants the use of multiple sequencing chemistry, multiple alignment tools, multiple variant callers which may not be viable in terms of time and money for individual investigators with limited informatics know-how. Biologists often lack the requisite training to deal with the huge amount of data produced by NGS runs and face difficulty in choosing from the list of freely available analytical tools for NGS data analysis. Hence, there is a need to customise the NGS data analysis pipeline to preferentially retain true variants by minimising the incidence of false positives and make the choice of right analytical tools easier. To this end, we have sampled different freely available tools used at the alignment and post alignment stage suggesting the use of the most suitable combination determined by a simple framework of pre-existing metrics to create significant datasets. 相似文献
98.
99.
NADH oxidase system of Agrobacterium tumefaciens 总被引:2,自引:0,他引:2
100.