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1.
S. Wehmeier A. S. Varghese S. S. Gurcha B. Tissot M. Panico P. Hitchen H. R. Morris G. S. Besra A. Dell M. C. M. Smith 《Molecular microbiology》2009,71(2):421-433
Previously mutations in a putative protein O -mannosyltransferase (SCO3154, Pmt) and a polyprenol phosphate mannose synthase (SCO1423, Ppm1) were found to cause resistance to phage, φC31, in the antibiotic producing bacteria Streptomyces coelicolor A3(2). It was proposed that these two enzymes were part of a protein O-glycosylation pathway that was necessary for synthesis of the phage receptor. Here we provide the evidence that Pmt and Ppm1 are indeed both required for protein O-glycosylation. The phosphate binding protein PstS was found to be glycosylated with a trihexose in the S. coelicolor parent strain, J1929, but not in the pmt − derivative, DT1025. Ppm1 was necessary for the transfer of mannose to endogenous polyprenol phosphate in membrane preparations of S. coelicolor . A mutation in ppm1 that conferred an E218V substitution in Ppm1 abolished mannose transfer and glycosylation of PstS. Mass spectrometry analysis of extracted lipids showed the presence of a glycosylated polyprenol phosphate (PP) containing nine repeated isoprenyl units (C45 -PP). S. coelicolor membranes were also able to catalyse the transfer of mannose to peptides derived from PstS, indicating that these could be targets for Pmt in vivo . 相似文献
2.
No consensus exists concerning the mechanisms, distribution,or adaptive significance of consciousness. Agreement on anyone of these issues would aid in resolving others. Given a reliablebehavioral or neuroanatomical test for consciousness, we couldmap its distribution and describe its evolution. Conversely,if we knew its distribution, we could assess its adaptive valueand look for similarly distributed neuroanatomies to help usget at its mechanisms. Morgan's Canonthe rule that we should avoid attributinghumanlike mental states to other animals whenever possibleimpedesthe use of the comparative method in unraveling this knot. Ifinterpreted in this context as a parsimony criterion, Morgan'sCanon is logically equivalent to epiphenomenalism. It is parsimoniousif and only if conscious mental events play no causal role inhuman behavior and human consciousness has no adaptive significance.Rejecting this conclusion entails rejecting the parsimony interpretationof Morgan's Canon. 相似文献
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Plantations of radiata pine (P. radiata D.Don) on soils previously under legume based pastures have a high incidence of stem deformity compared with forest soils.
A comparison of soil properties and tree nutrition of 5 to 7 year-old radiata pine on former pastures in the first part of
the study showed that stem deformity was strongly correlated with mineralisation of soil N and in particular with nitrification.
Other soil properties that have changed as a result of pasture improvement, e.g. pH, available P and Mn, were only partially
correlated with stem deformity. In the second part of the study, the role of N availability and other soil properties in the
expression of deformity was further investigated in a separate field experiment on soils formerly under native eucalypt forest,
tobacco cropping, and improved pasture. Young radiata pine plantings were treated with lime, phosphorus, and nitrogen applied
as urea and sodium nitrate. Liming increased soil pH by around 1.5 units, raised exchangeable Ca2+ and decreased available Mn. Soil mineral N content was only marginally affected by liming. Superphosphate increased soil
available P and raised levels of P in foliage. Changes in soil pH, availability of P, Mn, and B did not affect growth or stem
deformity at any of the sites. In contrast, application of N fertilisers at 200 and 600 kg N ha-1 increased mineral N content and stimulated nitrification, particularly at the forest site. The high rate of N fertiliser
increased basal area at the forest site by 45%, but also raised the level of stem deformity from 12% to 56%. At the tobacco
and pasture sites, this treatment did not increase growth and did not significantly raise stem deformity above the already
high basic level of deformity (63%). Implications of stem deformity in young plantations of radiata pine on potential utilisation
later in the rotation are discussed. 相似文献
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3H-thymidine incorporation and DNA-polymerase activity during early hours of wheat embryo germination at two viability levels
have been studied. The patterns of two biosynthetic activities, as well as the dependence of DNA synthesis on protein synthesis,
indicated the presence of a delay in the early phase of imbibition of the aged embryos with respect to viable germs. 相似文献
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Anne Dell Howard R. Morris 《Biochemical and biophysical research communications》1982,106(4):1456-1462
Using a combination of Fast Atom Bombardment lonisation and High Field Magnet — Mass Spectrometry we demonstrate here the ability to observe, for the first time, the accurate molecular weights of polypeptides or other important bioorganic substances up to 6000 Dalton in size. This claim is substantiated with data on intact unreduced Insulin and on the intact sweet protein Monellin, which consists of three polypeptide chains. 相似文献
8.
Soto E LaMon V Griffin M Keirstead N Beierschmitt A Palmour R 《Journal of wildlife diseases》2012,48(3):603-611
Klebsiella pneumoniae is a zoonotic, Gram-negative member of the family Enterobacteriaceae and is the causative agent of nosocomial septicemic, pneumonic, and urinary tract infections. Recently, pathogenic strains of K. pneumoniae sharing a hypermucoviscosity (HMV) phenotype have been attributed to multisystemic abscessation in both human and nonhuman primates. Although K. pneumoniae is a well-recognized zoonotic agent, there is a lack of general information including adequate diagnostic methods or treatments for nonhuman primates. In an effort to increase the body of knowledge of this enigmatic pathogen, K. pneumoniae isolates from African green monkeys (Chlorocebus aethiops sabaeus) on the island of St. Kitts, West Indies were genotypically and phenotypically characterized. Genetic fingerprints generated by PCR-mediated genomic fingerprinting, phenotypic characterization, and antimicrobial susceptibility all identified a high degree of similarity between the HMV and non-HMV K. pneumoniae isolates. The results obtained from this work will help establish a baseline for the development of efficacious diagnostic methods and treatment strategies for both human and nonhuman primates. 相似文献
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