Calcineurin is associated with the cytoskeleton of cultured neurons and has a role in the acquisition of polarity.

Calcineurin is a calmodulin-dependent serine-threonine phosphatase found in many cell types but most abundant in neurons. To determine its localization in developing neurons, dissociated cultures from embryonic day 15 rat cerebellum were analyzed immunocytochemically after treatment with cytoskeletal-disrupting drugs. During the initial outgrowth of neurites, calcineurin is enriched in growth cones where its localization depends upon the integrity of both microtubules and actin filaments. Treatment with cytochalasin shifts calcineurin from the growth cone to the neurite shaft, and with nocadozole calcineurin translocates to the cell body. Therefore calcineurin is well positioned to mediate interactions between cytoskeletal systems during neurite elongation. By 14 d in culture, when the neurons have developed extensive neuronal contacts and synapses are present, calcineurin is predominantly in the neurite shaft. Incubation of cultured cells with Cyclosporin A or a specific peptide, both of which selectively inhibit calcineurin's phosphatase activity, prevented axonal elongation. Because the microtubule-associated protein tau appears to play a key role in asymmetric neurite elongation, we examined modifications in its phosphorylation state resulting from calcineurin inhibition. In contrast to the normal development of cerebellar macroneurons in which reactivity with the phosphorylation-dependent antibody, tau-1, progressively increases, there was a persistent inhibition of tau-1 reactivity in cells exposed to Cyclosporin A. These findings suggest a role for calcineurin in regulating tau phosphorylation and possibly modulating other steps required for the determination of polarity.     

Heme biosynthesis in mammalian systems: evidence of a Schiff base linkage between the pyridoxal 5'-phosphate cofactor and a lysine residue in 5-aminolevulinate synthase.

5-Aminolevulinate synthase is the first enzyme of the heme biosynthetic pathway in nonplant higher eukaryotes. Murine erythroid 5-aminolevulinate synthase has been purified to homogeneity from an Escherichia coli overproducing strain, and the catalytic and spectroscopic properties of this recombinant enzyme were compared with those from nonrecombinant sources (Ferreira, G.C. & Dailey, H.A., 1993, J. Biol. Chem. 268, 584-590). 5-Aminolevulinate synthase is a pyridoxal 5'-phosphate-dependent enzyme and is functional as a homodimer. The recombinant 5-aminolevulinate synthase holoenzyme was reduced with tritiated sodium borohydride and digested with trypsin. A single peptide contained the majority of the label. The tritiated peptide was isolated, and its amino acid sequence was determined; it corresponded to 15 amino acids around lysine 313, to which pyridoxal 5'-phosphate is bound. Significantly, the pyridoxyllysine peptide is conserved in all known cDNA-derived 5-aminolevulinate synthase sequences and is present in the C-terminal (catalytic) domain. Mutagenesis of the 5-aminolevulinate synthase residue, which is involved in the Schiff base linkage with pyridoxal 5'-phosphate, from lysine to alanine or histidine abolished enzyme activity in the expressed protein.     

Enhancing estimation methods for integrating probability and nonprobability survey samples with machine-learning techniques. An application to a Survey on the impact of the COVID-19 pandemic in Spain

Web surveys have replaced Face-to-Face and computer assisted telephone interviewing (CATI) as the main mode of data collection in most countries. This trend was reinforced as a consequence of COVID-19 pandemic-related restrictions. However, this mode still faces significant limitations in obtaining probability-based samples of the general population. For this reason, most web surveys rely on nonprobability survey designs. Whereas probability-based designs continue to be the gold standard in survey sampling, nonprobability web surveys may still prove useful in some situations. For instance, when small subpopulations are the group under study and probability sampling is unlikely to meet sample size requirements, complementing a small probability sample with a larger nonprobability one may improve the efficiency of the estimates. Nonprobability samples may also be designed as a mean for compensating for known biases in probability-based web survey samples by purposely targeting respondent profiles that tend to be underrepresented in these surveys. This is the case in the Survey on the impact of the COVID-19 pandemic in Spain (ESPACOV) that motivates this paper. In this paper, we propose a methodology for combining probability and nonprobability web-based survey samples with the help of machine-learning techniques. We then assess the efficiency of the resulting estimates by comparing them with other strategies that have been used before. Our simulation study and the application of the proposed estimation method to the second wave of the ESPACOV Survey allow us to conclude that this is the best option for reducing the biases observed in our data.     

Evaluation of Probiotic Properties of Novel Brazilian Lactiplantibacillus plantarum Strains

Probiotics and Antimicrobial Proteins - Beneficial effects of Lactiplantibacillus plantarum strains have been widely reported. Knowing that the effects of probiotic bacteria are strain-dependent,...     

Computer-aided comparison of protein electrophoretic patterns for grouping and identification of heterotrophic bacteria from mineral water

The microflora of a natural mineral water was studied immediately after bottling (T0) and after 7 d storage (T7) during 6 months, and isolates were clustered by SDS-PAGE of wholecell protein profiles. Isolates from each cluster were further characterized by API 20NE, fatty acid composition and quinone profiles. The numerical analysis of the electrophoregrams of all bacteria isolated from the mineral water formed 15 clusters and five unclustered strains. Except for five minor clusters, all clusters were composed of strains isolated over several months. The numerical analysis of the electrophoregrams of bacteria isolated immediately after bottling formed 15 clusters while after 7 d storage only four of these populations could be isolated, indicating that populations present in the mineral water were stable and that changes occurring after bottling probably resulted from a selection process. Only one unclustered strain was identified simultaneously by all the systems, as Sphingomonas paucimobilis. The monitoring of the aquifer and the bottling system, and the construction of a large database with bacteria of the autochthonous flora allows the detection of alterations in the aquifer by changes in the microflora.     

Chromatographic methods for amylases

This review surveys recent developments in chromatographic methods for the separation of amylases from complex extracts, including the separation of isozymes. It contains two tables with the properties and molecular characteristics of α- and β-amylases from different sources as well as an updated review of methods for the determination of amylase activity. The main subject of this review is a detailed evaluation of the application of newly developed chromatographic methods for the purification of amylases.     

Circadian Changes in Anxiolysis-Related Behavior of Syrian Hamsters. Correlation with Hypothalamic GABA Release

The diurnal variations in anxiolysis and exploratory behavior were examined in a plus-maze paradigm in Syrian hamsters exposed to 14 h light: 10 h dark photoperiods or to constant darkness for 3 days. The percent of time spent in open arms and the percent of entries to open arms (both indexes of anxiety-related behavior) as well as the number of crosses to both arms (an index of locomotor behavior) showed significant daily variations under the two lighting conditions, maxima being found at night (2400-0400 h). Flumazenil (5 mg/kg) injected at the middle of the light (at 1600 h) or dark period (at 0400 h) decreased by 39-54 % anxiolysis-related behavior without affecting locomotor activity significantly. 3 H-?-aminobutyric acid (GABA) release from preoptic-medial basal hypothalamic explants obtained from hamsters exposed to 14 h light: 10 h dark photoperiods attained maximal values at 2400-0400 h. The results further supported the existence of circadian changes in anxiolysis-related behavior in Syrian hamsters that correlated with an increased hypothalamic GABA release.