RESUMO
The study of microbial communities associated with spontaneous fermentation of agave juice for tequila production is required to develop starter cultures that improve both yield and quality of the final product. Quantification by HPLC of primary metabolites produced during the fermentations was determined. A polyphasic approach using plate count, isolation and identification of microorganisms, denaturing gradient gel electrophoresis and next generation sequencing was carried out to describe the diversity and dynamics of yeasts and bacteria during small-scale spontaneous fermentations of agave juice from two-year samplings. High heterogeneity in microbial populations and fermentation parameters were observed, with bacteria showing higher diversity than yeast. The core microorganisms identified were Saccharomyces cerevisiae and Lactobacillus fermentum. Practices in tequila production changed during the two-year period, which affected microbial community structure and the time to end fermentation. Bacterial growth and concomitant lactic acid production were associated with low ethanol production, thus bacteria could be defined as contaminants in tequila fermentation and efforts to control them should be implemented.
Assuntos
Bebidas Alcoólicas/microbiologia , Bactérias/metabolismo , Leveduras/isolamento & purificação , Agave/química , Agave/microbiologia , Bebidas Alcoólicas/análise , Bactérias/química , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , Etanol/metabolismo , Fermentação , Cinética , Limosilactobacillus fermentum/química , Limosilactobacillus fermentum/metabolismo , Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Leveduras/química , Leveduras/genética , Leveduras/metabolismoRESUMO
Native lactic acid bacteria (LAB) are capable of growing during winemaking, thereby strongly affecting wine quality. The species of LAB present in musts, wines during malolactic fermentation (MLF), and barrels/filters were investigated in wineries from the emerging wine region of Queretaro, México using multiplex PCR and culture. The resistance to wine-like conditions (WLC): ethanol (10, 12, and 13%), SO2 (30 mgâ l-1), and low pH (3.5) of native LAB strains was also studied. Five species were detected within 61 samples obtained: Oenococcus oeni, Lactobacillus plantarum, Pediococcus parvulus, Lactobacillus hilgardi, and Lactobacillus brevis. Four species (excepting L. brevis) were found in must; O. oeni and P. parvulus were ubiquitous in wine and L. plantarum and L. brevis were mainly present at the initial stage of MLF, while L. hilgardii was mostly detected at the advanced stage. Furthermore, some species detected in barrel/filter, prove them to be hazardous reservoirs. From 822 LAB isolates, only 119 resisted WLC with 10% ethanol; the number of strains able to grow in WLC with 13% ethanol decreased approximately by 50%, O. oeni being the most versatile species with 65% of resistant isolates, while Lactobacillus spp. and P. parvulus were the most strongly affected, especially those recovered from barrel/filter, with less than 10% of resistant isolates. This study evidences the presence of local strains able to be used as starter cultures, and also enabled the assessment of the risks derived from the presence of spoilage LAB strains resistant to WLC.
RESUMO
A fundamental problem in neurophysiology is the understanding of neuronal mechanisms by which the central nervous system produces a sequence of voluntary or involuntary motor acts from a diverse repertory of movements. These kinds of transitions between motor acts are extremely complex; however, they could be analyzed in a more simple form in decerebrate animals in the context of spinal central pattern generation. Here, we present for the first time a physiological phenomenon of post-scratching locomotion in which decerebrate cats exhibit a compulsory locomotor activity after an episode of scratching. We found flexor, extensor and intermediate single interneurons rhythmically firing in the same phase during both scratching and the subsequent post-scratching locomotion. Because no changes in phase of these neurons from scratching to post-scratching locomotion were found, we suggest that in the lumbar spinal cord there are neurons associated with both motor tasks. Moreover, because of its high reproducibility we suggest that the study of post-scratching fictive locomotion, together with the unitary recording of neurons, could become a useful tool to study neuronal mechanisms underlying transitions from one rhythmic motor task to another, and to study in more detail the central pattern generator circuitry in the spinal cord.
Assuntos
Geradores de Padrão Central/fisiologia , Locomoção/fisiologia , Metiltransferases/fisiologia , Atividade Motora/fisiologia , Neurônios Motores/fisiologia , Medula Espinal/fisiologia , Animais , Comportamento Animal/fisiologia , Gatos , Estado de Descerebração , Orelha , Vértebras Lombares , Nervo Tibial/fisiologiaRESUMO
In English, odds ratio is a basic epidemiological measure approximating the relative risk. Odds ratio has been translated into Spanish in several ways, which has produced great terminological confusion. On the other hand, the English word odds is often used in epidemiology or statistics English textbooks, alone or as part of other expressions, but always keeping a definite mathematical meaning, which calls for a similarly definite term in Spanish. We discuss several translations of odds ratio found in the literature and propose the Spanish word "posibilidades" as a translation of odds and "razón de posibilidades" as a translation of odds ratio.
Assuntos
Razão de Chances , Terminologia como Assunto , TraduçãoRESUMO
Sixty-nine Latin American refugees with a mean age of 31 years participated in this study. The knowledge about dental health before and after reading a self-instructional manual in Spanish was tested by questionnaires. The test persons were also interviewed about their dietary habits. The results showed an improvement of 30% of right answers after reading the manual and that a frequent sugar consumption was common. This indicates that a self-instructional manual can be of value in oral health prevention in a similar group of non-resident immigrants.