Estudos de toxidez de alumínio em genótipos de soja e milho cultivados em bioensaios,

A soja (Glycine max) e o milho (Zea mayz) são culturas importantes para o desenvolvimento sócio-econômico do Rio Grande do Sul. Um fator que pode afetar a produtividade destas culturas é a presença de alumínio em níveis tóxicos que ocorre, principalmente, em solos ácidos. A utilização de genótipos adaptados é uma estratégia para o manejo integrado dos cultivos em solos ácidos. O presente estudo teve como objetivo determinar as concentrações de cálcio e aluminio adequadas a realização de bioensaios para a classificação de genótipos de soja e milho quanto a tolerância à toxidez de aluminio. Foram utilizados três genótipos de soja (6001, 8100 e AL 72.) e dois genótipos de milho (P3081 e TRAKTOR). Os genótipos foram cultivados, pela técnica de bioensaios, em diferentes concentrações de cálcio e alumínio. A concentração de 2,5 mmol dm-3 de cálcio foi adequada para a realização de estudos em bíoensaios nos genótipos de soja e milho, não promovendo restrições no crescimento da raiz principal. A concentração de 0,005 mmol dm-3 de alumínio para soja e 0,025 mmol dm-3 de alumínío para milho, combínadas com 2,5 mmol dm-3 de cálcio permitem diferenciar os genótipos de soja e milho em uma escala de tolerância ao alumini

Heterochromatin characterization and ribosomal gene location in two monotypic genera of bloodsucker bugs (Cimicidae, Heteroptera) with holokinetic chromosomes and achiasmatic male meiosis

Abstract Members of the family Cimicidae (Heteroptera: Cimicomorpha) are temporary bloodsuckers on birds and bats as primary hosts and humans as secondary hosts. Acanthocrios furnarii (2n = 12 = 10 + XY, male) and Psitticimex uritui (2n = 31 = 28 + X 1 X 2 Y, male) are two monotypic genera of the subfamily Haematosiphoninae, which have achiasmatic male meiosis of collochore type. Here, we examined chromatin organization and constitution of cimicid holokinetic chromosomes by determining the amount, composition and distribution of constitutive heterochromatin, and number and location of nucleolus organizer regions (NORs) in both species. Results showed that these two bloodsucker bugs possess high heterochromatin content and have an achiasmatic male meiosis, in which three regions can be differentiated in each autosomal bivalent: (i) terminal heterochromatic regions in repulsion; (ii) a central region, where the homologous chromosomes are located parallel but without contact between them; and (iii) small areas within the central region, where collochores are detected. Acanthocrios furnarii presented a single NOR on an autosomal pair, whereas P. uritui presented two NORs, one on an autosomal pair and the other on a sex chromosome. All NORs were found to be associated with CMA 3 bright bands, indicating that the whole rDNA repeating unit is rich in G + C base pairs. Based on the variations in the diploid autosomal number, the presence of simple and multiple sex chromosome systems, and the number and location of 18S rDNA loci in the two Cimicidae species studied, we might infer that rDNA clusters and genome are highly dynamic among the representatives of this family

International Society of Sports Nutrition Position Stand: Probiotics.

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of probiotic supplementation to optimize the health, performance, and recovery of athletes. Based on the current available literature, the conclusions of the ISSN are as follows: 1)Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO).2)Probiotic administration has been linked to a multitude of health benefits, with gut and immune health being the most researched applications.3)Despite the existence of shared, core mechanisms for probiotic function, health benefits of probiotics are strain- and dose-dependent.4)Athletes have varying gut microbiota compositions that appear to reflect the activity level of the host in comparison to sedentary people, with the differences linked primarily to the volume of exercise and amount of protein consumption. Whether differences in gut microbiota composition affect probiotic efficacy is unknown.5)The main function of the gut is to digest food and absorb nutrients. In athletic populations, certain probiotics strains can increase absorption of key nutrients such as amino acids from protein, and affect the pharmacology and physiological properties of multiple food components.6)Immune depression in athletes worsens with excessive training load, psychological stress, disturbed sleep, and environmental extremes, all of which can contribute to an increased risk of respiratory tract infections. In certain situations, including exposure to crowds, foreign travel and poor hygiene at home, and training or competition venues, athletes' exposure to pathogens may be elevated leading to increased rates of infections. Approximately 70% of the immune system is located in the gut and probiotic supplementation has been shown to promote a healthy immune response. In an athletic population, specific probiotic strains can reduce the number of episodes, severity and duration of upper respiratory tract infections.7)Intense, prolonged exercise, especially in the heat, has been shown to increase gut permeability which potentially can result in systemic toxemia. Specific probiotic strains can improve the integrity of the gut-barrier function in athletes.8)Administration of selected anti-inflammatory probiotic strains have been linked to improved recovery from muscle-damaging exercise.9)The minimal effective dose and method of administration (potency per serving, single vs. split dose, delivery form) of a specific probiotic strain depends on validation studies for this particular strain. Products that contain probiotics must include the genus, species, and strain of each live microorganism on its label as well as the total estimated quantity of each probiotic strain at the end of the product's shelf life, as measured by colony forming units (CFU) or live cells.10)Preclinical and early human research has shown potential probiotic benefits relevant to an athletic population that include improved body composition and lean body mass, normalizing age-related declines in testosterone levels, reductions in cortisol levels indicating improved responses to a physical or mental stressor, reduction of exercise-induced lactate, and increased neurotransmitter synthesis, cognition and mood. However, these potential benefits require validation in more rigorous human studies and in an athletic population

Meiotic studies in Dysdercus Guérin Méneville, 1831 (Heteroptera: Pyrrhocoridae). II. Evidence on variations of the diffuse stage between wild and laboratory-inbred populations of Dysdercus chaquensis Freiberg, 1948

Dysdercus Guérin Méneville, 1831 comprises insect species that are often serious pests of cotton both in the Old and New World, representing the only taxon from Pyrrhocoridae in the Neotropical Region. The genus is cytologically characterized by possession of holokinetic chromosomes and a prereductional type of meiosis. So far, only seven species from the Old World and five species from the Neotropical Region have been cytogenetically described. In the present report we compare the male meiosis from both natural and inbred populations of Dysdercus chaquensis Freiberg, 1948. Our results demonstrated that even though both populations share the same diploid chromosome number, the presence of a diffuse stage was found to be committed to the wild population of the species. Furthermore, the diffuse stage was found in a high frequency in all analysed wild specimens, indicating the long duration of this period among the regular meiosis of D. chaquensis. Taking into account that the diffuse stage is connected with an intense and long period of cellular growth, and with an important transcriptional activity, the absence of this stage in all the inbred specimens of D. chaquensis could be related with the lack of unfavourable physiological conditions due to the environmental uniformity along seven years of inbreeding

Gut microbiota and voluntary alcohol consumption

Alcohol is part of the usual diet of millions of individuals worldwide. However, not all individuals who drink alcohol experience the same effects, nor will everyone develop an alcohol use disorder. Here we propose that the intestinal microbiota (IMB) helps explain the different consumption patterns of alcohol among individuals. 507 humans participated in this study and alcohol consumption and IMB composition were analyzed. On the other hand, in 80 adult male Wistar rats, behavioral tests, alcohol intoxication, fecal transplantation, administration of antibiotics and collection of fecal samples were performed. For identification and relative quantification of bacterial taxa was used the bacterial 16 S ribosomal RNA gene. In humans, we found that heavy episodic drinking is associated with a specific stool type phenotype (type 1, according to Bristol Stool Scale; p < 0.05) and with an increase in the abundance of Actinobacteria (p < 0.05). Next, using rats, we demonstrate that the transfer of IMB from alcohol-intoxicated animals causes an increase in voluntary alcohol consumption in transplant-recipient animals (p < 0.001). The relative quantification data indicate that the genus Porphyromonas could be associated with the effect on voluntary alcohol consumption. We also show that gut microbiota depletion by antibiotics administration causes a reduction in alcohol consumption (p < 0.001) and altered the relative abundance of relevant phyla such as Firmicutes, Bacteroidetes or Cyanobacteria (p < 0.05), among others. Benjamini-Hochberg false discovery rate (FDR) correction was performed for multiple comparisons. These studies reveal some of the consequences of alcohol on the IMB and provide evidence that manipulation of IMB may alter voluntary alcohol consumption

Bacteriocinogenic Effect of Lactobacillus sakei 2a on Microbiological Quality of Fermented Sardinella brasiliensis

Lactobacillus sakei 2a is a bacteriocin producer strain and, in this work, it’s effects as a starter culture in the fermentation process of sardine (Sardinella brasiliensis) fillets were observed at different concentrations of NaCl (2, 4 and 6%) and glucose (2 and 4%), to determine it’s ability to produce organic acids and consequent pH reduction. Experiments were carried out independently, with only one parameter (NaCl or glucose) varying at a time. After 21 days of fermentation the deteriorative bacteria concentration reached 9.7 Log10 CFU. g-1 corresponding to 6% NaCl and 4% glucose. Little differences were observed in lactic acid production when 2 and 4% glucose were added, since total acidity was 1.32 and 1.34% respectively, the experiments with 6% NaCl presented the best results. Initial pH of sardine fillets was 6 and after 21 days pH values were 3.8, 3.9 and 4 for the experiments with 2, 4 and 6% NaCl. This may have been due to the inhibitory properties of NaCl over the deteriorative bacteria. After 21 days of the fermentation process lactic acid bacteria concentrations were 14.5 Log10 CFU.g-1. The ratio protein nitrogen and total soluble nitrogen was typical of a cured fish