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The article presents a study which explores the application of microcosm system to evaluate the effects of linear alkylbenzene sulfonate (LAS) on the community structure of Alphaproteobacteria, Actinobacteria, and Acidobacteria in the soil. The bacteria were analyzed through temperature gradient gel electrophoresis (TGGE). It was found that LAS concentration significantly influences the development of bacterial community structure.

Organochlorine compounds have been linked to increased risk of several cancers. Despite reductions in their use and fugitive release, they remain one of the most important groups of persistent pollutants to which humans are exposed, primarily through dietary intake. We designed a case-control study to assess the risk of colorectal cancer with exposure to these chemicals, and their potential interactions with genetic alterations in the tumors. A subsample of cases (n = 132) and hospital controls (n = 76) was selected from a larger case-control study in Barcelona, Catalonia, Spain. We measured concentrations in serum of several organochlorines by gas chromatography. We assessed point mutations in K-ras and p53 genes in tissue samples by polymerase chain reaction/single-strand conformation polymorphism and assessed expression of p53 protein by immunohistochemical methods. An elevated risk of colorectal cancer was associated with higher serum concentrations of mono-ortho polychlorinated biphenyl (PCB) congeners 28 and 118. The odds ratio for these mono-ortho PCBs for middle and higher tertile were, respectively, 1.82 [95% confidence interval (CI), 0.90-3.70] and 2.94 (95% CI, 1.39-6.20). Alpha-hexachlorocyclohexane, hexachlorobenzene, and p,p'-DDE (4,4'-dichlorodiphenyltrichloroethene) showed nonsignificant increases in risk. Risk associated with mono-ortho PCBs was slightly higher for tumors with mutations in the p53 gene but was not modified by mutations in K-ras. Mono-ortho PCBs were further associated with transversion-type mutations in both genes. These results generate the hypothesis that exposure to mono-ortho PCBs contributes to human colorectal cancer development. The trend and magnitude of the association, as well as the observation of a molecular fingerprint in tumors, raise the possibility that this finding may be causal. [ABSTRACT FROM AUTHOR]

Metastatic progression in ductal breast carcinomas are related to apoptosis in primary tumors. Frameshift mutations in a single-repeat sequence within the coding region (G)8 of the pro-apoptotic Bax gene have been related to microsatellite instability (MSI) and progression of some carcinomas and lymphomas. The aim of this study was to explore whether the extended lifespan of breast cancer cells can also be triggered by Bax mutation in ductal-breast carcinomas, and whether breast cancer cell MSI is related to the loss of apoptosis. For this purpose we studied frameshift mutations of a microsatellite (G)8 in the third exon of the Bax gene in a series of 105 ductal breast carcinomas, at T1 and T2–3 stages, 45 of which had lymph node metastasis. We analyzed MSI in five sequences of DNA isolated from normal and tumor tissue samples taken from 86 patients, and we explored the relationship between MSI and tumor apoptosis status. Bax mutation was not present in ductal breast carcinomas. MSI (two or more markers altered) was detected in 11.6% of tumors. Loss of apoptosis occurred in 80% (8/10) tumors with MSI, versus 17.8% of tumors without MSI (χ2 test, p=0.0004), independently of Bax protein expression. We conclude that frameshift mutations of a microsatellite (G)8 of the Bax gene are not critical for the loss of apoptosis in breast cancer, and that loss of apoptosis may be a consequence of overexpression of anti-apoptotic protein Bcl-2 or Bcl-xL. Moreover, MSI in breast carcinomas might be the cause of loss of an apoptotic pathway that is not induced by frameshift mutations of a microsatellite (G)8 of the Bax gene. [ABSTRACT FROM AUTHOR]

Abstract Background The cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats. Results Our results show no variation in the expression of nitric oxide synthase isoforms with aging, although, we have detected some changes in the cellular distribution pattern of the inducible isoform particularly in the cerebellar nuclei. There is also an increase in nitric oxide synthase activity, as well as greater protein-nitration levels, and maintenance of nitrogen oxides (NOx) levels in the senescent cerebellum. Conclusions The nitric oxide/nitric oxide syntahses system suffers from a number of changes, mainly in the inducible nitric oxide synthase distribution and in overall nitric oxide synthases activity in the senescent cerebellum, which result in an increase of the protein nitration. These changes might be related to the oxidative damage detected with aging in the cerebellum.

Introducción: La microbiota digestiva juega un papel fundamental en la salud del hospedador, protegiendo frente a enfermedades crónicas e infecciosas. Ciertos componentes de la dieta, como los PRM (formados durante el procesado de alimentos), podrían afectar a la microbiota, aunque los datos existentes en la bibliografía son escasísimos y controvertidos (Tuohy et al. (2006). Estos compuestos están presentes en la dieta de los adolescentes en una elevada proporción. Objetivos: El propósito de este estudio fue analizar el efecto de dos dietas, una pobre (DP) y otra rica (DR) en PRM, sobre la composición de la microbiota intestinal en adolescentes, comparando asimismo con los datos básales obtenidos durante su dieta habitual (OH). Material y métodos: 20 adolescentes varones sanos (11-14 años) consumieron las dietas DP y DR durante dos semanas. Tras dichos periodos, así como durante su DH, se recogieron muestras fecales de los sujetos, a partir de las cuales se aisló el ADN total. La composición de la microbiota fecal se determinó mediante qPCR utilizando oligonucleótidos específicos. Resultados: El consumo de la DR dio lugar a un descenso en el número de bacterias totales y de lactobacilos respecto a las dietas DP y DH. No hubo diferencias en el número de enterobacterias entre las dietas DH y DR, mientras que la DB supuso un incremento de dichos valores. Conclusiones: El consumo de una dieta rica en alimentos altamente procesados podría tener un efecto adverso sobre la composición de la microbiota intestinal, al afectar negativamente a bacterias potencialmente beneficiosas para la salud, y no modificar las potencialmente perjudiciales. [ABSTRACT FROM AUTHOR]

Background: The cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats.Results: Our results show no variation in the expression of nitric oxide synthase isoforms with aging, although, we have detected some changes in the cellular distribution pattern of the inducible isoform particularly in the cerebellar nuclei. There is also an increase in nitric oxide synthase activity, as well as greater protein-nitration levels, and maintenance of nitrogen oxides (NOx) levels in the senescent cerebellum.Conclusions: The nitric oxide/nitric oxide synthases system suffers from a number of changes, mainly in the inducible nitric oxide synthase distribution and in overall nitric oxide synthases activity in the senescent cerebellum, which result in an increase of the protein nitration. These changes might be related to the oxidative damage detected with aging in the cerebellum. [ABSTRACT FROM AUTHOR]