State University of New York System

About: State University of New York System is a education organization based out in Albany, New York, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 54077 authors who have published 78070 publications receiving 2985160 citations.

Neurodegenerative diseases: an overview of environmental risk factors.

Abstract: The population of the United States is aging, and an ever-increasing number of Americans are afflicted with neurodegenerative diseases. Because the pathogenesis of many of these diseases remains unknown, we must consider that environmental factors may play a causal role. This review provides an overview of the epidemiologic evidence for environmental etiologies for neurodegenerative diseases such as Alzheimer disease, Parkinson disease, parkinsonian syndromes (multiple system atrophy and progressive supranuclear palsy), and amyotrophic lateral sclerosis. Epidemiologic evidence for an association between environmental agents' exposure and neurodegenerative diseases is not conclusive. However, there are indications that there may be causal links, and the need for more research is obvious.

Need for DNA topoisomerase activity as a swivel for DNA replication for transcription of ribosomal RNA.

Abstract: Yeast strains with mutations in the genes for DNA topoisomerases I and II have been identified previously in both Saccharomyces cerevisiae1–3 and Schizosaccharomyces pombe4. The topoisomerase II mutants (top2) are conditional-lethal temperature-sensitive (ts) mutants. They are defective in the termination of DNA replication and the segregation of daughter chromosomes2–5, but otherwise appear to replicate and transcribe DNA normally. Topoisomerase I mutants (top1), including strains with null mutations are viable and exhibit no obvious growth defects, demonstrating that DNA topoisomerase I is not essential for viability in yeast1,4,6,7. In contrast to the single mutants, top1 top2 ts double mutants from both Schizosaccharomyces pombe and Saccharomyces cerevisiae grow poorly at the permissive temperature and stop growth rapidly at the non-permissive temperature4,7. Here we report that DNA and ribosomal RNA synthesis are drastically inhibited in an S. cerevisiae top1 top2 ts double mutant at the restrictive temperature, but that the rate of poly(A)+ RNA synthesis is reduced only about threefold and transfer RNA synthesis remains relatively normal. The results suggest that DNA replication and at least ribosomal RNA synthesis require an active topoisomerase, presumably to act as a swivel to relieve torsional stress, and that either topoisomerase can perform the required function (except in termination of DNA replication where topoisomerase II is required).

Presence of human friends and pet dogs as moderators of autonomic responses to stress in women.

Abstract: Autonomic responses were measured while 45 adult women performed a standard experimental stress task in the laboratory with only the experimenter present and 2 weeks later at home in the presence of a female friend, pet dog, or neither. Results demonstrated that autonomic reactivity was moderated by the presence of a companion, the nature of whom was critical to the size and direction of the effect. Ss in the friend condition exhibited higher physiological reactivity and poorer performance than subjects in the control and pet conditions. Ss in the pet condition showed less physiological reactivity during stressful tasks than Ss in the other conditions. The results are interpreted in terms of the degree to which friends and pets are perceived as evaluative during stressful task performance. Physiological reactivity was consistent across the laboratory and field settings.

Recombination in Escherichia coli and the definition of biological species.

Abstract: The DNA sequence of part of the gnd (6-phosphogluconate dehydrogenase) gene was determined for eight wild strains of Escherichia coli and for Salmonella typhimurium. Since a region of the trp (tryptophan) operon and the phoA (alkaline phosphatase) gene have been sequenced from the same strains, the gene trees for these three regions were determined and compared. Gene trees are different from species or strain trees in that a gene tree is derived from a particular segment of DNA, whereas a species or strain tree should be derived from many such segments and is the tree that best represents the phylogenetic relationship of the species or strains. If there were no recombination in E. coli, the gene trees for different genes would not be statistically different from the strain tree or from each other. But, if the gene trees are significantly different, there must have been recombination. Methods are proposed that show these gene trees to be statistically different. Since the gene trees are different, we conclude that recombination is important in natural populations of E. coli. Finally, we suggest that gene trees can be used to create an operational means of defining bacterial species by using the biological species definition.

Protein-primed RNA synthesis by purified poliovirus RNA polymerase

Abstract: A small protein, VPg, is covalently linked to the 5′ end of the plus-stranded poliovirus genomic RNA1,2,3. Poliovirus messenger RNA, identical in nucleotide sequence to genomic RNA, is not capped at its 5′ end by the methylated structure that is common to most eukaryotic mRNAs. These discoveries presented two problems. First, as cap structures are usually required for translation of mRNA into protein, how does this uncapped viral RNA act as a template for translation? Second, what is the function of VPg? The identification of the internal ribosomal-entry site, which allows the entry of ribosomes into viral mRNA independently of the 5′ mRNA end, has solved the first conundrum4,5,6. Here we describe the resolution of the second problem. VPg is linked to the genomic RNA through the 5′-terminal uridylic acid of the RNA. We show that VPg can be uridylylated by the poliovirus RNA polymerase 3Dpol. Uridylylated VPg can then prime the transcription of polyadenylate RNA by 3Dpol to produce VPg-linked poly(U). Initiation of transcription of the poliovirus genome from the polyadenylated 3′ end therefore depends on VPg.