Translation inhibitors stabilize Escherichia coli mRNAs independently of ribosome protection

Translation inhibitors such as chloramphenicol in prokaryotes or cycloheximide in eukaryotes stabilize many or most cellular mRNAs. In Escherichia coli, this stabilization is ascribed generally to the shielding of mRNAs by stalled ribosomes. To evaluate this interpretation, we examine here how inhibitors affect the stabilities of two untranslated RNAs, i.e., an engineered lacZ mRNA lacking a ribosome binding site, and a small regulatory RNA, RNAI. Whether they block elongation or initiation, all translation inhibitors tested stabilized these RNAs, indicating that stabilization does not necessarily reflect changes in packing or activity of translating ribosomes. Moreover, both the initial RNase E-dependent cleavage of RNAI and lacZ mRNA and the subsequent attack of RNAI by polynucleotide phosphorylase and poly(A)-polymerase were slowed. Among various possible mechanisms for this stabilization, we discuss in particular a passive model. When translation is blocked, rRNA synthesis is known to increase severalfold and rRNA becomes unstable. Meanwhile, the pools of RNase E and polynucleotide phosphorylase, which, in growing cells, are limited because these RNases autoregulate their own synthesis, cannot expand. The processing/degradation of newly synthesized rRNA would then titrate these RNases, causing bulk mRNA stabilization.

Protection against hemorrhagic shock in mice genetically deficient in poly(ADP-ribose)polymerase

Hemorrhagic shock (HS) and resuscitation leads to widespread production of oxidant species. Activation of the enzyme poly(ADP-ribose) polymerase (PARP) has been shown to contribute to cell necrosis and organ failure in various disease conditions associated with oxidative stress. We tested the hypothesis whether PARP activation plays a role in the multiple organ dysfunction complicating HS and resuscitation in a murine model of HS and resuscitation by using mice genetically deficient in PARP (PARP−/−) and their wild-type littermates (PARP+/+). Animals were bled to a mean blood pressure of 45 mmHg (1 mmHg = 133 Pa) and resuscitated after 45 min with isotonic saline (2× volume of shed blood). There was a massive activation of PARP, detected by poly(ADP-ribose) immunohistochemistry, which localized to the areas of the most severe intestinal injury, i.e., the necrotic epithelial cells at the tip of the intestinal villi, and colocalized with tyrosine nitration, an index of peroxynitrite generation. Intestinal PARP activation resulted in gut hyperpermeability, which developed in PARP+/+ but not PARP−/− mice. PARP−/− mice were also protected from the rapid decrease in blood pressure after resuscitation and showed an increased survival time, as well as reduced lung neutrophil sequestration. The beneficial effects of PARP suppression were not related to a modulation of the NO pathway nor to a modulation of signaling through IL-6, which similarly increased in both PARP+/+ and PARP−/− mice exposed to HS. We propose that PARP activation and associated cell injury (necrosis) plays a crucial role in the intestinal injury, cardiovascular failure, and multiple organ damage associated with resuscitated HS.

Cold related mortalities and protection against cold in Yakutsk, eastern Siberia: observation and interview study

Objective To assess how effectively measures adopted in extreme cold in Yakutsk control winter mortality.

Estrogen receptor α, not β, is a critical link in estradiol-mediated protection against brain injury

Estradiol protects against brain injury, neurodegeneration, and cognitive decline. Our previous work demonstrates that physiological levels of estradiol protect against stroke injury and that this protection may be mediated through receptor-dependent alterations of gene expression. In this report, we tested the hypothesis that estrogen receptors play a pivotal role in mediating neuroprotective actions of estradiol and dissected the potential biological roles of each estrogen receptor (ER) subtype, ERα and ERβ, in the injured brain. To investigate and delineate these mechanisms, we used ERα-knockout (ERαKO) and ERβ-knockout (ERβKO) mice in an animal model of stroke. We performed our studies by using a controlled endocrine paradigm, because endogenous levels of estradiol differ dramatically among ERαKO, ERβKO, and wild-type mice. We ovariectomized ERαKO, ERβKO, and the respective wild-type mice and implanted them with capsules filled with oil (vehicle) or a dose of 17β-estradiol that produces physiological hormone levels in serum. One week later, mice underwent ischemia. Our results demonstrate that deletion of ERα completely abolishes the protective actions of estradiol in all regions of the brain; whereas the ability of estradiol to protect against brain injury is totally preserved in the absence of ERβ. Thus, our results clearly establish that the ERα subtype is a critical mechanistic link in mediating the protective effects of physiological levels of estradiol in brain injury. Our discovery that ERα mediates protection of the brain carries far-reaching implications for the selective targeting of ERs in the treatment and prevention of neural dysfunction associated with normal aging or brain injury.

Vaccination for protection of retinal ganglion cells against death from glutamate cytotoxicity and ocular hypertension: Implications for glaucoma

Our group recently demonstrated that autoimmune T cells directed against central nervous system-associated myelin antigens protect neurons from secondary degeneration. We further showed that the synthetic peptide copolymer 1 (Cop-1), known to suppress experimental autoimmune encephalomyelitis, can be safely substituted for the natural myelin antigen in both passive and active immunization for neuroprotection of the injured optic nerve. Here we attempted to determine whether similar immunizations are protective from retinal ganglion cell loss resulting from a direct biochemical insult caused, for example, by glutamate (a major mediator of degeneration in acute and chronic optic nerve insults) and in a rat model of ocular hypertension. Passive immunization with T cells reactive to myelin basic protein or active immunization with myelin oligodendrocyte glycoprotein-derived peptide, although neuroprotective after optic nerve injury, was ineffective against glutamate toxicity in mice and rats. In contrast, the number of surviving retinal ganglion cells per square millimeter in glutamate-injected retinas was significantly larger in mice immunized 10 days previously with Cop-1 emulsified in complete Freund's adjuvant than in mice injected with PBS in the same adjuvant (2,133 ± 270 and 1,329 ± 121, respectively, mean ± SEM; P < 0.02). A similar pattern was observed when mice were immunized on the day of glutamate injection (1,777 ± 101 compared with 1,414 ± 36; P < 0.05), but not when they were immunized 48 h later. These findings suggest that protection from glutamate toxicity requires reinforcement of the immune system by antigens that are different from those associated with myelin. The use of Cop-1 apparently circumvents this antigen specificity barrier. In the rat ocular hypertension model, which simulates glaucoma, immunization with Cop-1 significantly reduced the retinal ganglion cell loss from 27.8% ± 6.8% to 4.3% ± 1.6%, without affecting the intraocular pressure. This study may point the way to a therapy for glaucoma, a neurodegenerative disease of the optic nerve often associated with increased intraocular pressure, as well as for acute and chronic degenerative disorders in which glutamate is a prominent participant.

Cancer-predisposing mutations within the RING domain of BRCA1: Loss of ubiquitin protein ligase activity and protection from radiation hypersensitivity

BRCA1 is a breast and ovarian cancer-specific tumor suppressor that seems to be involved in transcription and DNA repair. Here we report that BRCA1 exhibits a bona fide ubiquitin (Ub) protein ligase (E3) activity, and that cancer-predisposing mutations within the BRCA1 RING domain abolish its Ub ligase activity. Furthermore, these mutants are unable to reverse γ-radiation hypersensitivity of BRCA1-null human breast cancer cells, HCC1937. Additionally, these mutations within the BRCA1 RING domain are not capable of restoring a G2 + M checkpoint in HCC1937 cells. These results establish a link between Ub protein ligase activity and γ-radiation protection function of BRCA1, and provide an explanation for why mutations within the BRCA1 RING domain predispose to cancer. Furthermore, we propose that the analysis of the Ub ligase activity of RING-domain mutations identified in patients may constitute an assay to predict predisposition to cancer.

Control of HIV-1 viremia and protection from AIDS are associated with HLA-Bw4 homozygosity

Certain HLA-B antigens have been associated with lack of progression to AIDS. HLA-B alleles can be divided into two mutually exclusive groups based on the expression of the molecular epitopes HLA-Bw4 and HLA-Bw6. Notably, in addition to its role in presenting viral peptides for immune recognition, the HLA-Bw4, but not HLA-Bw6, motif functions as a ligand for a natural killer cell inhibitory receptor (KIR). Here, we show that profound suppression of HIV-1 viremia is significantly associated with homozygosity for HLA-B alleles that share the HLA-Bw4 epitope. Furthermore, homozygosity for HLA-Bw4 alleles was also significantly associated with the ability to remain AIDS free and to maintain a normal CD4 T cell count in a second cohort of HIV-1-infected individuals with well defined dates of seroconversion. This association was independent of the presence of a mutation in CC chemokine receptor 5 (CCR5) associated with resistance to HIV-1 infection, and it was independent of the presence of HLA alleles that could potentially confound the results. We conclude that homozygosity for HLA-Bw4-bearing B alleles is associated with a significant advantage and that the HLA-Bw4 motif is important in AIDS pathogenesis.

Library outreach: addressing Utah's “Digital Divide”

A “Digital Divide” in information and technological literacy exists in Utah between small hospitals and clinics in rural areas and the larger health care institutions in the major urban area of the state. The goals of the outreach program of the Spencer S. Eccles Health Sciences Library at the University of Utah address solutions to this disparity in partnership with the National Network of Libraries of Medicine—Midcontinental Region, the Utah Department of Health, and the Utah Area Health Education Centers. In a circuit-rider approach, an outreach librarian offers classes and demonstrations throughout the state that teach information-access skills to health professionals. Provision of traditional library services to unaffiliated health professionals is integrated into the library's daily workload as a component of the outreach program. The paper describes the history, methodology, administration, funding, impact, and results of the program.

Protection from superoxide damage associated with an increased level of the YggX protein in Salmonella enterica

The deleterious effect of superoxide radicals on cell growth and survival is predominately caused by rapid oxidation of labile [Fe-S] clusters in proteins. Oxidation of these clusters releases Fe(II) ions, which participate in Fenton chemistry that damages DNA. Here it is shown that elevated levels of the YggX protein increase the resistance of Salmonella enterica to superoxide stress, reverse enzymatic defects attributed to oxidized [Fe-S] clusters, and decrease the spontaneous mutation frequency. The data are consistent with a model in which YggX protects protein [Fe-S] clusters from oxidation.

Internet Civil Liberties in the U.S. and the Protection of the Modern Terrorist

This capstone examines the civil liberties of the modern terrorist and explicates the right to freedom of speech for terrorist organizations and their use of the internet. Terrorist organizations use the internet to promote ideas, recruit members, organize the flow of information, and coordinate actions. During the war on terror the US Patriot Act became law allowing for U.S. government censorship and surveillance of internet traffic and many believe these acts are a threat to civil liberties. Terrorist organizations have the right to express their views, however unpopular, and censoring or restricting web sites diminishes civil liberties for all, which democracies and liberal societies are founded upon.

Sexualización en la publicidad digital de marcas de moda infantil: iniciativas ciudadanas y mecanismos de denuncia

Los niños son presentados como objetos sexuales en gran parte, según el debate social, debido a la actividad de marcas y medios vinculados a la moda. La metodología llevada a cabo combina un análisis de contenido de los catálogos de publicidad de moda infantil en Internet en el contexto español, con el objetivo de ver si las marcas de moda infantil sexualizan a los niños en Internet; una revisión de las iniciativas de denuncia en Internet para conocer si la sociedad civil está concienciada; y una revisión de la normativa jurídica y ética en la publicidad digital para verificar si hay una protección a los niños. Los hallazgos apuntan que casi la mitad de los niños de los catálogos (el 45.8%) muestran atributos que los sexualizan, que las niñas son las más perjudicadas -un 48.9% frente al 38.2% de los niños- y las marcas que sexualizan más son las originalmente de adulto. Además, la sexualización se atribuye a la libertad creativa y al beneficio de las marcas. Las iniciativas y quejas se concentran en padres, Gobierno y asociaciones de consumidores. Se recomienda mayor información para que los ciudadanos inicien los procesos de protección legal y ética previstos para proteger a los niños.

Des-re-territorialização e áreas protegidas na Amazônia: reflexões a partir do caso da Estação Ecológica da Terra do Meio-Pa-Brasil

A criação de espaços territoriais especialmente protegidos é uma estratégia utilizada pelo homem desde a antiguidade, objetivando a reserva de áreas com características naturais necessárias à manutenção ou à reprodução cultural de populações humanas específicas, regulando e limitando o acesso e a apropriação de certos recursos e/ou reservando-os para usos ou futuros. Os processos de criação dessas “áreas especialmente protegidas” foram contudo intensificados, no final do século XX, com a percepção da finitude dos recursos naturais, e acelerados pelo florescimento e a consolidação do capitalismo, agora “globalizado”. Quando tais processos, são orientados por interesses diversos de grupos sociais hegemônicos, são comuns não só a desestruturação do modo de vida dos usuários dos recursos naturais tradicionalmente relacionados aos “territórios especiais”, como também a expulsão de grupos não-hegemônicos neles já instalados, sempre que suas práticas culturais sejam consideradas como incompatíveis com os fins e os objetivos da área que se pretende proteger. Entre os tipos de área especialmente protegida estabelecidos pela legislação brasileira, encontram-se as Unidades de Conservação da Natureza (UC). Criadas por Lei com o objetivo de conservar a biodiversidade brasileira, as UC vem sendo palco de diversos conflitos ambientais envolvendo populações tradicionais em todos os biomas brasileiros, mas pode ser mais facilmente evidenciada na Amazônia, aonde a megabiodiversidade a proteger se sobrepõe a territórios ocupados por diversas etnias indígenas e outros povos tradicionais. Os conflitos são intensificados quando a categoria de manejo da UC criada restringe o acesso e altera os modos de apropriação e/ou dos usos tradicionais dos recursos naturais da área por parte dos residentes, inclusive impedindo a continuidade da permanência das populações no interior da UC, no caso o grupo das UC de Proteção Integral. À luz dos debates que vem sendo travados no campo da ecologia política, tais processos conflituosos estariam associados à desterritorialização dos grupos afetados pela criação da UC, nos quais o Estado brasileiro seria o responsável direto. Independentemente das diversas abordagens acadêmicas para o conceito de “território”, entende-se atualmente que a territorialização e a desterritorialização (com consequente reterritorialização) são processos interrelacionados e circularmente conectados, não podendo ser compreendidos separadamente. Assim, o objetivo do presente trabalho é contribuir para a compreensão desses processos de des-re-terrritorialização, avaliando como alguns mecanismos previstos na Lei do Sistema Nacional das Unidades de Conservação para o reassentamento das populações anteriormente residentes vem sendo aplicados, no sentido de promover processos de reterritorialização. As reflexões apresentadas se dão a partir do caso dos ribeirinhos e colonos residentes na Estação Ecológica da Terra do Meio, Pará, Brasil. A partir da avaliação, são propostas alternativas para minimizar a situação de injustiça ambiental na qual se encontram esses atores sociais específicos.

Brasília, capital-patrimônio: sinergia para o desenvolvimento

Brasília impõe-se como um interessante caso a ser estudado. Distingue-se de todas as demais cidades do Brasil (e talvez do mundo), mas, ainda assim, reflete a quase totalidade das complexas questões que atingem qualquer grande cidade. A análise de seus processos de patrimonialização e de gestão territorial-patrimonial revela riqueza e singularidade históricas, além de revelar contradições e alta complexidade. O presente ensaio, de cunho teórico-exploratório, propõe-se a analisar o Plano de Preservação do Conjunto Urbanístico de Brasília – PPCUB, projeto de Lei Complementar proposto como política pública de proteção do patrimônio urbano, em busca de relações e conexões entre o contexto sociopolítico de construção da cidade ideal, seu desenvolvimento real e sua consagração como Patrimônio Mundial. Apenas por meio da sinergia de interesses e da ação conjunta dos diversos atores/agentes envolvidos na dinâmica urbana será possível transformar a excepcionalidade e o valor universal em acessibilidade territorial e valor local, dois pilares do desenvolvimento.