87 research outputs found
Onset of foraging and lifespan of Africanized honey bees (Apis mellifera) infected with different levels of Nosema ceranae spores in Neotropical Mexico
International audienceAbstractNosema ceranae is a microsporidium pathogen widely spread around the world. Negative effects on foraging behavior and longevity of EHB colonies have been associated with this pathogen as well as possible population losses, but its effects have not been studied in tropical adapted honey bees. We studied the interaction between this pathogen and Africanized honey bees (AHB) in the Yucatan peninsula of Mexico where N. ceranae has only been detected since 2008. Non-infected and artificially infected workers with two different spore concentrations were introduced in observation hives to evaluate the onset and duration of foraging and longevity. The results showed precocious foraging, a reduction of the duration of foraging and a decrease in the longevity of infected bees compared with non-infected ones. However, the results indicate that although negative effects can be caused by N. ceranae in AHB, these were of a moderate magnitude compared with similar reports on EHB in temperate areas. Further research is necessary to evaluate the long-term effect of N. ceranae on AHBs in relation to colony dynamics to better understand the absence of significant colony losses associated with this pathogen in tropical and subtropical Mexico
Ion distribution dynamics near the Earth's bow shock: first measurements with the 2D ion energy spectrometer CORALL on the INTERBALL/Tail-probe satellite
International audienceThe dynamics of the ion distribution function near the Earth's bow shock is studied on the basis of quasi-3D measurements of ion energy spectra in the range of 30?24200 eV/q with the Russian-Cuban CORALL instrument on the INTERBALL/Tail-probe satellite. The instrument was designed for observations of magnetospheric plasma and measures ions, in an angular range of 36°?144° from the Earth-Sun direction. Ion populations generated by the Earth bow shock are often observed upstream from the bow shock. In the solar-wind stream compressed and heated by the passing of very dense magnetic cloud (CME), two types of these ion populations were measured upstream and before the bow shock crossing on 25 August 1995 at 07:37 UT. Both populations were observed in the energy range above 2 keV. At ~06:20 UT, when the angle between the direction of the interplanetary magnetic field and normal to the bow shock VBn was ? 43° the instrument observed a narrow, fast (~800 km/s) field-aligned beam moving from the Earth. At ~07:30, when Bn ? 28°, the wide ion pitch-angle distribution was observed. A similar suprathermal ion population is observed in the magnetosheath simultaneously with the solar-wind ion population being heated and deflected from the Sun-Earth direction. The similarity of observations during the mentioned time-interval and under usual solar-wind conditions allows us to conclude that types of suprathermal ion populations upstream and downstream from the bow shock do not depend on the solar-wind disturbance generated by magnetic cloud
Tercera revascularización miocárdica quirúrgica. Único paciente presentado en Cuba
A 49 years old male, white, smoker patient is presented. A severe coronary disease was demonstrated by means of coronariography. Surgical myocardial revascularization was necessarily performed in three opportunities.Se presenta un paciente de 49 años de edad, masculino, blanco, fumador. Se demostró por coronariografía la presencia de una enfermedad coronaria severa y se determinó necesario realizar revascularización miocárdica quirúrgica en tres oportunidades
Factors of the epidemiological triad that influence the persistence of human papilloma virus infection in women with systemic lupus erythematosus
We studied the epidemiologic triad-related factors influencing human papilloma virus (HPV) persistence in Mexican women with systemic lupus erythematosus (SLE). Patients aged ?18 years with SLE (American College of Rheumatology criteria), with and without HPV persistence, were selected. Groups were analyzed by (1) host: clinical disease characteristics; (2) agent: (I) infectious (prevalence, incidence, HPV genotype and co-infections (?2 HPV genotypes or mycoplasmas)), (II) chemical (contraceptives and immunosuppressive drugs) and (III) physical (vitamin D deficiency) and (3) environment. A total of 121 SLE patients were selected over a two-year period. (1) Host: mean age 45.8 years and disease duration 12.7 years. (2) Agent: (I) infectious. HPV infection prevalence in the second sample was 26.4%, high-risk HPV genotypes 21.5% and co-infections 7.4%. HPV infection incidence was 13.2%, persistence 13.2% and clearance 15.7%. (II) Chemical: use of oral hormonal contraceptives 5% and immunosuppressive treatment 97.5%. (III) Physical: Vitamin D levels were similar in both groups. (3) Environment: (I) natural. A total of 60.6% of patients were residents of Puebla City. (II) Social: The mean education level was 10.9. Poverty levels were: III degree 52.4%, IV degree 28% and II degree 17%. (III) Cultural behavioral: Onset of sexual life was 20.5 years, 10% had ?3 sexual partners and 51.2% were postmenopausal. In conclusion, no factor of the epidemiologic triad was associated with HPV infection prevalence. © The Author(s) 2018
O-GlcNAc transferase invokes nucleotide sugar pyrophosphate participation in catalysis
Protein O-GlcNAcylation is an essential post-translational modification on hundreds of intracellular proteins in metazoa, catalyzed by O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) using unknown mechanisms of transfer and substrate recognition. Through crystallographic snapshots and mechanism-inspired chemical probes, we define how human OGT recognizes the sugar donor and acceptor peptide and uses a new catalytic mechanism of glycosyl transfer, involving the sugar donor α-phosphate as the catalytic base as well as an essential lysine. This mechanism seems to be a unique evolutionary solution to the spatial constraints imposed by a bulky protein acceptor substrate and explains the unexpected specificity of a recently reported metabolic OGT inhibitor. © 2012 Nature America, Inc. All rights reserved
Municipal mortality due to thyroid cancer in Spain
BACKGROUND: Thyroid cancer is a tumor with a low but growing incidence in Spain. This study sought to depict its spatial municipal mortality pattern, using the classic model proposed by Besag, York and Mollié. METHODS: It was possible to compile and ascertain the posterior distribution of relative risk on the basis of a single Bayesian spatial model covering all of Spain's 8077 municipal areas. Maps were plotted depicting standardized mortality ratios, smoothed relative risk (RR) estimates, and the posterior probability that RR > 1. RESULTS: From 1989 to 1998 a total of 2,538 thyroid cancer deaths were registered in 1,041 municipalities. The highest relative risks were mostly situated in the Canary Islands, the province of Lugo, the east of La Coruña (Corunna) and western areas of Asturias and Orense. CONCLUSION: The observed mortality pattern coincides with areas in Spain where goiter has been declared endemic. The higher frequency in these same areas of undifferentiated, more aggressive carcinomas could be reflected in the mortality figures. Other unknown genetic or environmental factors could also play a role in the etiology of this tumor
Lessons from One Fastidious Bacterium to Another: What Can We Learn about Liberibacter Species from Xylella fastidiosa
Huanglongbing is causing economic devastation to the citrus industry in Florida, and threatens the industry everywhere the bacterial pathogens in the Candidatus Liberibacter genus and their insect vectors are found. Bacteria in the genus cannot be cultured and no durable strategy is available for growers to control plant infection or pathogen transmission. However, scientists and grape growers were once in a comparable situation after the emergence of Pierce’s disease, which is caused by Xylella fastidiosa and spread by its hemipteran insect vector. Proactive quarantine and vector control measures coupled with interdisciplinary data-driven science established control of this devastating disease and pushed the frontiers of knowledge in the plant pathology and vector biology fields. Our review highlights the successful strategies used to understand and control X. fastidiosa and their potential applicability to the liberibacters associated with citrus greening, with a focus on the interactions between bacterial pathogen and insect vector. By placing the study of Candidatus Liberibacter spp. within the current and historical context of another fastidious emergent plant pathogen, future basic and applied research to develop control strategies can be prioritized
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