An unusual "morphologic" variant of BF S

In the course of family studies of haplotypes of the alleles of the sixth chromosome loci HLA-A, C, B, D/DR, BF, C2, C4A, C4B, and glyoxalase I, we encountered an unusual BF variant. Its mobility was similar to BF F but it appeared to have a lesser intensity after straining with Coomassie Blue, and it was demonstrated by crossed immunoelectrophoresis to be present in lower concentration. It was therefore designated BF FQL. This variant was found on the haplotype HLA-A1, B17, DR7, BF*FQL, C2*C, C4A*6, C4B*1, GLO2. All other haplotypes of this type so far identified carry the BF variant BF S. Following activation of serum samples with zymosan, BF was analyzed by both agarose electrophoresis and isoelectric focusing and immunofixation. On both treatments, serum with BF SFQL produced a Ba pattern identical to that of a sample which was BF S. The Bb pattern for F and S are similar but differ from those of the rare variants BF F1 and BF S1. The Bb pattern of BF FQL was, thus, as expected, the same as BF F or BF S. Hence, we conclude that the variant is a mutant from BF S with mobility similar to BF F. The mutation seemed also to have resulted in a lower concentration of product than normal.     

20S proteasomes and protein degradation "by default"

The degradation of the majority of cellular proteins is mediated by the proteasomes. Ubiquitin-dependent proteasomal protein degradation is executed by a number of enzymes that interact to modify the substrates prior to their engagement with the 26S proteasomes. Alternatively, certain proteins are inherently unstable and undergo "default" degradation by the 20S proteasomes. Puzzlingly, proteins are by large subjected to both degradation pathways. Proteins with unstructured regions have been found to be substrates of the 20S proteasomes in vitro and, therefore, unstructured regions may serve as signals for protein degradation "by default" in the cell. The literature is loaded with examples where engagement of a protein into larger complexes increases protein stability, possibly by escaping degradation "by default". Our model suggests that formation of protein complexes masks the unstructured regions, making them inaccessible to the 20S proteasomes. This model not only provides molecular explanations for a recent theoretical "cooperative stability" principle, but also provokes new predictions and explanations in the field of protein regulation and functionality.     

Methylation of Sindbis virus "26S" messenger RNA.

The main virus-specific messenger RNA species of Sindbis virus-infected hamster cells, the “26S” RNA, has been examined with regard to methylation status. Internal methylated residues and terminal methylated residues were present, in approximately equal amounts. The internal methyl groups were almost all in 5-methylcytosine residues and the terminal methyl groups were mainly in 7-methylguanine residues. Evidence is presented that these latter occur in “capped” 5′-termini with the novel structure m⁷G(5′)pppNp.     

16S rRNA phylogenetic investigation of the candidate division "Korarchaeota"

The environmental distribution and phylogeny of "Korarchaeota," a proposed ancient archaeal division, was investigated by using the 16S rRNA gene framework. Korarchaeota-specific primers were designed based on previously published sequences and used to screen a variety of environments. Korarchaeota 16S rRNA genes were amplified exclusively from high temperature Yellowstone National Park hot springs and a 9 degrees N East Pacific Rise deep-sea hydrothermal vent. Phylogenetic analyses of these and all available sequences suggest that Korarchaeota exhibit a high level of endemicity.     

Antibiotics sensitivity of "hospital" strains of S. typhimurium]

Sensitivity of Styphimurium strains isolated under conditions of a hospital infection to antibiotics were studied in comparison with the strains of the given serological type isolated from other sources and with the strains of other serological types of groups B, C, D and E. It was shown that the strains causing outbreaks of hospital infections were characterized by polyresistance to 7 out of 9 antibiotics tested. All the Salmonella strains tested were sensitive to gentamicin and about a half of them was sensitive to polymyxin M.     

Analysis of articulation of fricative praealveolar sibilant "S" in control population

Defective pronunciation of one or more mother language phones, i.e. dyslalia, represents the most frequent speech impairment both in children and adult people. Cases of persisting speech disorder need professional approach and help. The aim of the study was to obtain a model of physiological articulation of the sibilant "s" in children. The method of FFT spectral analysis was made use of. Results will serve for further use in evaluation of speech impairment.     

"In vivo" (35S)methionine interaction with rat liver tRNA

As part of a study to characterize the methionine role in tumorigenesis, we report that methionine sulfur interacts with rat liver tRNA "in vivo" (35S) radioactivity remained associated to the nucleic acid after a number of treatments, including tRNA deacylation. Similar data were obtained after administration of (methyl-3H) methionine, while no comparable tRNA labelling was detected when the aminoacid labelled in the aliphatic chain was given. Hplc analysis of (35S) tRNA enzymic hydrolysate showed two unidentified UV-absorbing radioactive peaks. NMR spectra of these two peaks did not reveal any thiomethyl group.     

Isolation and characterization of "8S" RNA in murine sarcoma virus-infected cells

Three new 8S RNA species were identified in rat cells chronically infected with Moloney Murine Sarcoma Virus. Among them, two have identical electrophoretic mobilities, nucleotide compositions and fingerprints with the 8S_A and 8S_BRNAs recently found in the mouse sarcoma-leukemia virus, M-MSV (MLV); the third cellular 8S component, called X, is not incorporated in the virus. Experiments of cellular 8S RNA heat treatment suggest that the 8S_A and 8S_B RNAs are conformational isomers of each other. The different relative proportions of the two A and B components in the host cell and in the virus and the role of the 8S RNA are discussed.     

Automated cryoelectron microscopy of "single particles" applied to the 26S proteasome

The 26S proteasome is a large molecular machine with a central role in intracellular protein degradation in eukaryotes. The 2.5 MDa complex, which is built from two copies each of more than 30 different subunits, is labile and prone to dissociation into subcomplexes. Hence it is difficult if not impossible, to obtain structurally homogeneous preparations and, as a consequence, it is very cumbersome to obtain large numbers of images of the holocomplex. In this communication, we describe an automated procedure for the acquisition of large data sets of cryoelectron micrographs. The application of this procedure to the 26S proteasome from Drosophila has allowed us to determine the three-dimensional structure of the complex to a resolution of 2.9 nm and the prospects for further improvements are good.     

Thiols of myosin. IV. "Abnormal" reactivity of S1 thiol and the conformational changes around S2 thiol.

The flexibility of the tertiary structure around the active site of myosin ATPase [EC 3.6.1.3] was studied using the reactivity of two specific thiol groups, S1 and S2, as a structural probe. The following four maleimide derivatives were used as thiol-directed reagents: N-ethylmaleimide (NEM), N-(4-methoxy-2-benzimidazolyl methyl) maleimide (MBM), N-(p-(2-benzimidazolyl)phenyl)maleimide (BIPM) and N-(4-dimethyl-amino-3,5-dinitrophenyl)maleimide (DDPM). 1. All the maleimide derivatives used activated the Ca2+-ATPase activity and inhibited the EDTA-ATPase activity, like NEM, indicating that they modified S1. The rate of modification of S1 by NEM and BIPM increased with increasing pH, while that by DDPM decreased. BIPM simultaneously modified S1 and S2. 2. S1 showed much higher reactivity toward the maleimides, except for BIPM, than did N-acetylcysteine (N-Ac-Cys) a low molecular-weight model compound. The extremely small pKa value of S1, 6.28, accounted for this high reactivity. In addition, the ATP-induced increase in its reactivity inducated that S1 was in a buried state. Kinetic analysis showed that the teritiary structure around S1 at alkaline pH differed from that at acidic pH. 3. The apparent rate constant of S2-modification with NEM was approximately one seven-hundredth and one four-hundredth of those of S1 and N-Ac-Cys, respectively. Fluorimetric studies using BIPM revealed that S2 in the buried state was exposed upon adding ATP; this was compensated by the burying of some other thiol group(s) (Sp). Non-linearity of the Arrhenius plots of the reaction rate of S2 suggested that the S2 region of myosin had different conformations at high and low temperatures, the transition temperature being 10--15degrees. This non-linearity completely disappeared in the presence of Mg2+-ATP. On the other hand, Arrhenius plots for the thiols reactive to BIPM did not show non-linearity in the presence or absence of ATP.     

乌体林斯联合化疗治疗耐多药肺结核疗效观察

目的探讨乌体林斯联合化疗治疗耐多药肺结核（MDR-TB）疗效。方法将146例耐多药肺结核患者随机分为乌体林斯加化疗的治疔组（76例）和仅用化疗的对照组（70例）。治疗组采用左氧氟沙星＋吡嗪酰胺＋乙胺丁醇＋利福喷丁＋异烟肼及乌体林斯1.72μg/m l深部肌注,每周2次;对照组单纯用左氧氟沙星＋吡嗪酰胺＋乙胺丁醇＋利福喷丁＋异烟肼方案治疗,疗程均为18个月。结果治疗6个月、12个月、18个月后,治疗组涂阳阴转率分别为67%、82%、92%,对照组涂阳阴转率分别为34%、44%、51%,痰菌阴转率治疗组显著高于对照组（P〈0.05）组。治疗组病灶吸收显著高于对照组。结论乌体林斯能增加肺结核患者的痰菌阴转率,促进病灶吸收好转,可以作为耐药性肺结核的辅助治疗。     

Characterization of the 70S Ribosome from Rhodopseudomonas palustris using an integrated "top-down" and "bottom-up" mass spectrometric approach

We present a comprehensive mass spectrometric approach that integrates intact protein molecular mass measurement ("top-down") and proteolytic fragment identification ("bottom-up") to characterize the 70S ribosome from Rhodopseudomonas palustris. Forty-two intact protein identifications were obtained by the top-down approach and 53 out of the 54 orthologs to Escherichia coli ribosomal proteins were identified from bottom-up analysis. This integrated approach simplified the assignment of post-translational modifications by increasing the confidence of identifications, distinguishing between isoforms, and identifying the amino acid positions at which particular post-translational modifications occurred. Our combined mass spectrometry data also allowed us to check and validate the gene annotations for three ribosomal proteins predicted to possess extended C-termini. In particular, we identified a highly repetitive C-terminal "alanine tail" on L25. This type of low complexity sequence, common to eukaryotic proteins, has previously not been reported in prokaryotic proteins. To our knowledge, this is the most comprehensive protein complex analysis to date that integrates two MS techniques.     

Transmissive drug resistance and virulence of "epidemic" strains of S. typhimurium]

A total of 59 "epidemic" strains of S. typhimurium and 52 cultures isolated from the cases with sporadic diseases were studied with respect to the nature of their resistance to 10 antibiotics and virulence for albino mice under conditions of subcutaneous and oral inoculation. The virulence of the cultures isolated from the cases with sporadic diseases was higher in the strains sensitive to antibiotics. The "epidemic" strains were characterized by the lowest virulence for the mice and resistance to 8-10 antibiotics simultaneously with the transmissive nature of resistance to 1-5 drugs. The transmissive nature of resistance to antibiotics and its spectrum may serve an additional epidemiological marker of the strains.