The molecular epidemiology of human immunodeficiency virus type 1 in six cities in Britain and Ireland

The authors sequenced the p17 coding regions of the gag gene from 211 patients infected either through injecting drug use (IDU) or by sexual intercourse between men from six cities in Scotland, N. England, N. Ireland, and the Republic of Ireland. All sequences were of subtype 5. Phylogenetic analysis revealed substantial heterogeneity in the sequences from homosexual men. In contrast, sequence from over 80% of IDUs formed a relatively tight cluster, distinct both from those of published isolates and of the gay men. There was no large-scale clustering of sequences by city in either risk group, although a number of close associations between pairs of individuals were observed. From the known date of the HIV-1 epidemic among IDUs in Edinburgh, the rate of sequence divergence at synonymous sites is estimated to be about 0.8%. On this basis it has been estimated that the date of divergence of the sequences among homosexual men to be about 1975, which may correspond to the origin of the B subtype epidemic

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 339)

This bibliography lists 105 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during July 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Randomised, controlled trial of effectiveness of ampicillin in mild acute respiratory infections in Indonesian children.

The recommended treatment for mild acute respiratory infections (ARI) in children is supportive care only, but many physicians, especially in developing countries, continue to prescribe antibiotic treatment because they believe it prevents progression to more severe ARI. To find out whether ampicillin treatment conferred any benefit over supportive care alone, a randomised, controlled trial was carried out among 889 children (under 5 years) with mild ARI in Indonesia. 447 were randomly allocated ampicillin (25-30 mg/kg body weight three times daily for 5 days) plus supportive care (continued breastfeeding, clearing of the nose, and paracetamol to control fever); 442 were allocated supportive care only. The treatment groups were almost identical after randomisation in terms of age, sex, level of parental education, history of measles immunisation, and fever. After 1 week the percentages cured were nearly identical (204 [46%] ampicillin; 209 [47%] control), as were the percentages of cases progressing to moderate ARI (56 [13%] vs 53 [12%]). The effect of treatment was not modified by age, sex, measles immunisation status, or the educational level of the parents. At the 2-week follow-up, the percentages cured were 62% (277) in the ampicillin group and 58% (256) in the control group; 14% of both groups had progressed to moderate ARI; and 24% (107) and 28% (123), respectively, still had mild ARI. None of the differences in outcome between the ampicillin and control groups was statistically significant. Thus, ampicillin plus supportive care offers no benefit over supportive care alone for treatment of mild ARI in young Indonesian children

Phylogenetic analysis of the SAP30 family of transcriptional regulators reveals functional divergence in the domain that binds the nuclear matrix

Background: Deacetylation of histones plays a fundamental role in gene silencing, and this is mediated by a corepressor complex containing Sin3 as an essential scaffold protein. In this report we examine the evolution of two proteins in this complex, the Sin3-associated proteins SAP30L and SAP30, by using an archive of protein sequences from 62 species.Results: Our analysis indicates that in tetrapods SAP30L is more similar than SAP30 to the ancestral protein, and the two copies in this group originated by gene duplication which occurred after the divergence of Actinopterygii and Sarcopterygii about 450 million years ago (Mya). The phylogenetic analysis and biochemical experiments suggest that SAP30 has diverged functionally from the ancestral SAP30L by accumulating mutations that have caused attenuation of one of the original functions, association with the nuclear matrix. This function is mediated by a nuclear matrix association sequence, which consists of a conserved motif in the C-terminus and the adjacent nucleolar localization signal (NoLS).Conclusion: These results add further insight into the evolution and function of proteins of the SAP30 family, which share many characteristic with nuclear scaffolding proteins that are intimately involved in regulation of gene expression. Furthermore, SAP30L seems essential to eukaryotic biology, as it is found in animals, plants, fungi, as well as some taxa of unicellular eukaryotes

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 341)

This bibliography lists 133 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during September 1990. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Identification of a Novel Self-Sufficient Styrene Monooxygenase from Rhodococcus opacus 1CP.

Sequence analysis of a 9-kb genomic fragment of the actinobacterium Rhodococcus opacus 1CP led to identification of an open reading frame encoding a novel fusion protein, StyA2B, with a putative function in styrene metabolism via styrene oxide and phenylacetic acid. Gene cluster analysis indicated that the highly related fusion proteins of Nocardia farcinica IFM10152 and Arthrobacter aurescens TC1 are involved in a similar physiological process. Whereas 413 amino acids of the N terminus of StyA2B are highly similar to those of the oxygenases of two-component styrene monooxygenases (SMOs) from pseudomonads, the residual 160 amino acids of the C terminus show significant homology to the flavin reductases of these systems. Cloning and functional expression of His10-StyA2B revealed for the first time that the fusion protein does in fact catalyze two separate reactions. Strictly NADH-dependent reduction of flavins and highly enantioselective oxygenation of styrene to (S)-styrene oxide were shown. Inhibition studies and photometric analysis of recombinant StyA2B indicated the absence of tightly bound heme and flavin cofactors in this self-sufficient monooxygenase. StyA2B oxygenates a spectrum of aromatic compounds similar to those of two-component SMOs. However, the specific activities of the flavin-reducing and styrene-oxidizing functions of StyA2B are one to two orders of magnitude lower than those of StyA/StyB from Pseudomonas sp. strain VLB120

Maize Streak Virus: diversity and virulence

Zea mays was first introduced to Africa in Ghana by Portuguese traders in the 16th century. The steady spread of maize cultivation since then has made it the most important cereal crop in Africa today. Whereas improved maize genotypes and agricultural techniques enable yearly yields above 10 tons hectare-1 in the developed world, yearly yields across Africa have remained low at about 1 ton hectare-1 in most countries. Although outmoded agricultural practices are the main reason for poor yields, maize pathogens inflict substantial additional losses. Of the many pathogens currently confronting maize farmers in Africa, Maize streak virus (MSV) is the most significant

Complete Mitochondrial Genome Sequence of Three Tetrahymena Species Reveals Mutation Hot Spots and Accelerated Nonsynonymous Substitutions in Ymf Genes

The ciliate Tetrahymena, a model organism, contains divergent mitochondrial (Mt) genome with unusual properties, where half of its 44 genes still remain without a definitive function. These genes could be categorized into two major groups of KPC (known protein coding) and Ymf (genes without an identified function). To gain insights into the mechanisms underlying gene divergence and molecular evolution of Tetrahymena (T.) Mt genomes, we sequenced three Mt genomes of T.paravorax, T.pigmentosa, and T.malaccensis. These genomes were aligned and the analyses were carried out using several programs that calculate distance, nucleotide substitution (dn/ds), and their rate ratios (ω) on individual codon sites and via a sliding window approach. Comparative genomic analysis indicated a conserved putative transcription control sequence, a GC box, in a region where presumably transcription and replication initiate. We also found distinct features in Mt genome of T.paravorax despite similar genome organization among these ∼47 kb long linear genomes. Another significant finding was the presence of at least one or more highly variable regions in Ymf genes where majority of substitutions were concentrated. These regions were mutation hotspots where elevated distances and the dn/ds ratios were primarily due to an increase in the number of nonsynonymous substitutions, suggesting relaxed selective constraint. However, in a few Ymf genes, accelerated rates of nonsynonymous substitutions may be due to positive selection. Similarly, on protein level the majority of amino acid replacements occurred in these regions. Ymf genes comprise half of the genes in Tetrahymena Mt genomes, so understanding why they have not been assigned definitive functions is an important aspect of molecular evolution. Importantly, nucleotide substitution types and rates suggest possible reasons for not being able to find homologues for Ymf genes. Additionally, comparative genomic analysis of complete Mt genomes is essential in identifying biologically significant motifs such as control regions