Divergent evolution and purifying selection of the flaA gene sequences in Aeromonas

<p>Abstract</p> <p>Background</p> <p>The bacterial flagellum is the most important organelle of motility in bacteria and plays a key role in many bacterial lifestyles, including virulence. The flagellum also provides a paradigm of how hierarchical gene regulation, intricate protein-protein interactions and controlled protein secretion can result in the assembly of a complex multi-protein structure tightly orchestrated in time and space. As if to stress its importance, plants and animals produce receptors specifically dedicated to the recognition of flagella. Aside from motility, the flagellum also moonlights as an adhesion and has been adapted by humans as a tool for peptide display. Flagellar sequence variation constitutes a marker with widespread potential uses for studies of population genetics and phylogeny of bacterial species.</p> <p>Results</p> <p>We sequenced the complete flagellin gene <it>(flaA</it>) in 18 different species and subspecies of <it>Aeromonas</it>. Sequences ranged in size from 870 (<it>A. allosaccharophila</it>) to 921 nucleotides (<it>A. popoffii</it>). The multiple alignment displayed 924 sites, 66 of which presented alignment gaps. The phylogenetic tree revealed the existence of two groups of species exhibiting different FlaA flagellins (FlaA1 and FlaA2). Maximum likelihood models of codon substitution were used to analyze <it>flaA </it>sequences. Likelihood ratio tests suggested a low variation in selective pressure among lineages, with an ω ratio of less than 1 indicating the presence of purifying selection in almost all cases. Only one site under potential diversifying selection was identified (isoleucine in position 179). However, 17 amino acid positions were inferred as sites that are likely to be under positive selection using the branch-site model. Ancestral reconstruction revealed that these 17 amino acids were among the amino acid changes detected in the ancestral sequence.</p> <p>Conclusion</p> <p>The models applied to our set of sequences allowed us to determine the possible evolutionary pathway followed by the <it>flaA </it>gene in <it>Aeromonas</it>, suggesting that this gene have probably been evolving independently in the two groups of <it>Aeromonas </it>species since the divergence of a distant common ancestor after one or several episodes of positive selection.</p> <p>Reviewers</p> <p>This article was reviewed by Alexey Kondrashov, John Logsdon and Olivier Tenaillon (nominated by Laurence D Hurst).</p

Percepción del estado de salud en varones y mujeres en las últimas etapas de la vida

ResumenObjetivoAnalizar las diferencias en la percepción del estado de salud de los varones y mujeres en las últimas etapas de la vida y explorar su relación con variables sociodemográficas y de salud.MétodosDatos procedentes de la Encuesta de Salud de Cataluña de 1994, de 1.459 varones y 1.993 mujeres de 60 y más años. Se realizó un análisis de la autovaloración del estado de salud según la edad, el sexo, la clase social, la declaración de enfermedades crónicas y la discapacidades y se aplicó un modelo de análisis multivariable de regresión logística teniendo en cuenta el diseño muestral.ResultadosEl 57,3% de las mujeres de 60 y más años declaraba no tener buena salud, frente al 43,6% de los varones. También fue superior la proporción de mujeres que padecía una o más discapacidades (41,2%) respecto a los varones (28,7%), así como la de enfermedades crónicas, el 92,2% de las mujeres y el 85,6% de los varones. En el modelo de regresión logística multivariable continúa manteniéndose una percepción de mala salud superior en las mujeres y aparecen como factores explicativos el número de enfermedades crónicas, padecer discapacidades y pertenecer a las clases sociales más desfavorecidas. La edad en interacción con las enfermedades crónicas amortigua el efecto de éstas en la valoración del estado de salud.ConclusionesEntre la población anciana, la percepción de mala salud fue superior en las mujeres incluso ajustando por otras variables explicativas significativas (clase social, edad, discapacidades y enfermedades crónicas). Padecer enfermedades crónicas y/o discapacidades constituyen los factores explicativos más importantes en la percepción del estado de salud. El impacto del padecimiento de enfermedades crónicas en relación con la percepción de mala salud disminuye a medida que los grupos son de mayor edad.SummaryObjectivesTo analyze the differences in health self-perception between men and women in the later stages of life and to assess their association with sociodemographic and health variables.MethodsData on 1,459 men and 1,993 women aged 60 or older from the 1994 Catalan Health Survey, were collected and an analysis of health self-perception according to age, gender, social class, reporting of chronic disease and handicaps was performed. Multivariate logistic regression analysis was used, taking into account the survey design.ResultsOf the women aged 60 and older, 57.3% reported poor health compared with 43.6% of men of the same age. The proportion of women with one or more handicaps was also greater (41.2%) than that of the men (28.7%), as was the case with chronic disease (92.2% inwomen and 85.6% in men). The multivariate model also revealed that health self-peerception was poorer among women than among men. Other explanatory factors were the number of chronic diseases, having handicaps, and being a member of a lower social class. Age interacted with the number of chronic diseases to mitigate the effect of chronic diseases on perceived health status.ConclusionsIn the elderly population, poor health self-perception was greater among women, even when other significant explanatory variable (social class, age, handicaps and chronic disease) were adjusted for. The most important explanatory factors in health self-perception were having chronic disease and/or handicaps. The impact of chronic disease on poor health self-perception decreased in older age groups

Haptoglobin genotype and risk of diabetic nephropathy in patients with type 1 diabetes mellitus: a study on a Spanish population

[en] BACKGROUND: Few reports have studied the possible association between the haptoglobin (Hp) genotype and the risk of diabetic nephropathy (DN) in type 1 diabetes (T1D), with conflicting results to date. AIMS: To study whether the 2-2 Hp genotype is associated with an increased risk of overt DN in a Spanish population with T1D. METHODS: We performed a case-control study in a Spanish population. CASES: T1D patients with end-stage renal disease (stage 5 of NKF-KDOQI), awaiting reno-pancreatic transplantation or having already been transplanted (reno-pancreatic or renal alone). CONTROLS: T1D patients, matched for sex and time of diabetes evolution, with preserved renal function and normal urinary albumin excretion. Hp genotyping was done using polymerase chain reaction and electrophoresis. RESULTS: We included 57 cases and 57 controls in the study. There were no statistically significant differences in gender (70% vs. 61% males, p=1.0) or the duration of diabetes (23.0 ± 6.7 vs. 20.8 ± 9.3 years; p=0.1), although the age of onset of diabetes was lower in the cases (14.1 ± 6.8 vs. 17.7 ± 10.1 years, p=0.03). The frequency of genotypes 1-1, 1-2 and 2-2 was 19.3%, 42.1% and 38.6% in cases and 17.5%, 49.1% and 33.4% in controls, respectively, with no statistically significant differences between groups (p=0.8). Conditional logistic regression analysis showed no significant association between genotype 2-2 of Hp and the development of DN (OR 1.14, CI 0.52-2.52). CONCLUSIONS: In our sample of a Spanish population with T1D, no association was found between the Hp genotype and risk of overt DN. [spa] Antecedentes: Pocos trabajos han estudiado la asociación entre el genotipo de la haptoglobina (Hp) y el riesgo de nefropatía diabética (ND) en pacientes con diabetes tipo 1 (DM1), con resultados contradictorios hasta ahora. Objetivos: Estudiar si el genotipo 2-2 de Hp se asocia a un incremento del riesgo de ND en población española con DM1. Métodos: Se diseñó un estudio de casos y controles. CASOS: pacientes con DM1 y enfermedad renal crónica estadio 5 de la NKF-KDOQI, en espera de trasplante reno-pancreático o que han sido trasplantados (reno-pancreático o renal aislado). CONTROLES: pacientes con DM1, apareados por sexo y tiempo de evolución de la diabetes, con función renal y excreción urinaria de albúmina normales. El genotipo de Hp se realizó mediante reacción en cadena de la polimerasa y electroforesis. Resultados: Incluimos 57 casos y 57 controles, sin diferencias estadísticamente significativas en el sexo (70 % frente a 61 % varones, p = 1,0) o duración de la diabetes (23,0 ± 6,7 frente a 20,8 ± 9,3 años; p = 0,1), aunque la edad de inicio de la diabetes fue menor en los casos (14,1 ± 6,8 frente a 17,7 ± 10,1 años, p = 0,03). La frecuencia de genotipos 1-1, 1-2 y 2-2 fue de 19,3 %, 42,1 % y 38,6 % en los casos y de 17,5 %, 49,1 % y 33,4 % en los controles, respectivamente, sin diferencias significativas (p = 0,8). El análisis de regresión logística condicional no mostró asociación entre el genotipo 2-2 de Hp y el desarrollo de ND (OR 1,14, IC 0,52-2,52). Conclusiones: En nuestra muestra de población española con DM1, no se ha hallado asociación entre el genotipo de Hp y el riesgo de ND

2018 consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary

Cancer of unknown primary (CUP) is defned as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They difer from other primary tumours in their biological features and how they spread, which means that they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, CUP can account for 2–9% of all cancer patients, mostly 60–75 years old. This article reviews the main clinical, pathological, and molecular studies conducted to analyse and determine the origin of CUP.The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed.The authors are grateful for the editorial assistance of Dr. Fernando Sánchez-Barbero of HealthCo (Madrid, Spain) in the production of this manuscript. SEOM and SEAP are grateful for the fnancial support for this project in the form of unrestricted grants from Ferrer Diagnostic, OncoDNA and Foundation Medicine/Roche

2018 consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary

Cancer of unknown primary (CUP) is defined as a heterogeneous group of tumours that present with metastasis, and in which attempts to identify the original site have failed. They differ from other primary tumours in their biological features and how they spread, which means that they can be considered a separate entity. There are several hypotheses regarding their origin, but the most plausible explanation for their aggressiveness and chemoresistance seems to involve chromosomal instability. Depending on the type of study done, CUP can account for 2-9% of all cancer patients, mostly 60-75years old. This article reviews the main clinical, pathological, and molecular studies conducted to analyse and determine the origin of CUP. The main strategies for patient management and treatment, by both clinicians and pathologists, are also addressed