Simón Bolívar University

About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.

Bacterial assemblages shifts from healthy to yellow band disease states in the dominant reef coral Montastraea faveolata

Abstract: Descriptions of microbial diversity in healthy and diseased corals are necessary first steps before further investigating the mechanisms that lead to coral pathology. This is the first study that characterizes the microbial associates from healthy corals to yellow band disease (YBD) lesions using two complementary screening techniques of bacterial 16S rRNA genes [amplified 16S ribosomal DNA restriction analysis (ARDRA) of clone libraries and denaturing gradient gel electrophoresis (DGGE)]. Both these techniques showed similar trends, namely a significant difference in the bacterial community and an increase in diversity from healthy to YBD diseased lesions. There was an increase in the number of sequences retrieved of potentially pathogenic bacteria in diseased tissues compared with healthy samples, most notably from the genus Vibrio. Furthermore, we also detected a number of known pathogenic bacteria within the natural healthy microbiota such as Vibrio carchariae and Vibrio harveyi, a result supporting previous studies, showing healthy corals have the ability to harbour these species.

Dynamics of energy and nutrient concentration and construction cost in a native and two alien C4 grasses from two neotropical savannas.

Abstract: In Venezuela, the alien grasses Melinis minutiflora Beauv. and Hyparrhenia rufa (Nees.) Stapf tend to displace the native savanna plant community dominated by Trachypogon plumosus (Humb. and Bonpl.) Nees. This occurs in either relatively wetter and fertile highland savannas or in drier and less fertile lowland savannas. Although the native and aliens are perennial C4 grasses, higher net assimilation leaf biomass per plant and germination rate of the latter are some causes for their higher growth rates and for their competitive success. The objective of this study is to compare seasonal tissue energy, N, P and K concentrations and the calculated construction costs (CC) between the native grass and either one of the alien grasses from lowland and highland savannas. We predict that, in order to out-compete native plants, alien grasses should be more efficient in resource use as evidenced by lower tissue energy and nutrient concentrations and CC.

The 60 kDa heat shock protein in human semen: relationship with antibodies to spermatozoa and Chlamydia trachomatis.

Abstract: The presence of the 60 kDa heat shock protein (hsp60) in seminal fluid and its relationship to sperm autoimmunity or a localized immune response to Chlamydia trachomatis were examined. Semen from 64 male partners of infertile couples with no history of a chlamydial infection were investigated. Hsp60 was identified by an enzyme-linked immunosorbent assay (ELISA) using a monoclonal anti-hsp60 antibody bound to wells of a microtitre plate and a polyclonal anti-hsp60 antibody for detection. Antisperm antibodies on motile spermatozoa were detected by immunobead binding, while antichlamydial immuno-globulin (Ig) A and IgG in seminal fluid were identified by a commercial ELISA (SeroELISA: Savyon Diagnostics, Beer-Sheva, Israel). RNA was purified from isolated seminal round mononuclear cells and tested for hsp60-specific mRNA by a reverse transcription polymerase chain reaction ELISA. Hsp60 was present in semen from nine (14.1%) men, 12 (18.8%) men had antisperm autoantibodies. 16 (25.0%) were positive for antichlamydial IgA and 17 (26.6%) had detectable hsp60-specific mRNA. The presence of hsp60 in semen correlated with the occurrence of antichlamydial IgA (P = 0.0005), hsp60 mRNA (P = 0.04) and antisperm antibodies (P = 0.05). Thus, hsp60 was present in a soluble form in semen primarily in men with evidence of immune system activation within their genital tract. The role of hsp60 in promoting or inhibiting immune responses within the genital tract remains to be determined.

The Impact of the COVID-19 Pandemic on Mental Disorders. A Critical Review.

Abstract: The COVID-19 pandemic has impacted the lives of the worldwide population. Citizens suffer the social, economic, physiological, and psychological effects of this pandemic. Primary sources, scientific articles, and secondary bibliographic indexes, databases, and web pages were used for a consensus critical review. The method was a narrative review of the available literature to summarize the existing literature addressing mental health concerns and stressors related to the COVID-19 pandemic. The main search engines used in the present research were PubMed, SciELO, and Google Scholar. We found the pandemic has had a direct impact on psychopathologies such as anxiety, increasing its ratios, and depression. Other syndromes such as burnout and post-traumatic stress disorder have increased with the pandemic, showing a larger incidence among medical personnel. Moreover, eating disorders and violence have also increased. Public authorities must prepare healthcare systems for increasing incidences of mental pathologies. Mental health apps are one of the tools that can be used to reach the general population.