Spliceosome-targeted therapies trigger an antiviral immune response in triple-negative breast cancer

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High-resolution crystal structures of transient intermediates in the phytochrome photocycle

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Demographic and environmental influences on life-history traits of isolated populations of the Andean catfish Astroblepus ubidiai

In this study, we examined the influence of demographic and environmental variables on the life histories of six remnant populations of the Andean catfishAstroblepus ubidiai (Actinopterygii; Siluriform) located in isolated refuges, and tested six predictions on the relationships between age at maturity, generation time, population density and juvenile and adult growth and survival rates. The three populations inhabiting the watershed with a direct connection to a major lake (Imbakucha) exhibited later maturity, a longer generation time, higher adult survivorship, a higher adult-to-juvenile survival ratio and lower biomass density than those of the adjacent, non-lacustrine watersheds. Across all six populations, there was a strong correlation between mean age at maturity and both the adult-to-juvenile survival ratio and biomass density. Study populations also showed a pattern of inverse density-dependence associated with Allee effects. We conclude that without limitations in the availability of environmental resources, higher population density can be negatively related to age at maturity. This relationship would be expected to become positive when carrying capacity of the systems is reached. Delayed maturity in the Imbakucha populations may be an adaptive response for increasing juvenile survival under stressful conditions.     

Occurrence of Drug-Resistant Bacteria in Two European Eel Farms

The occurrence of strains that are resistant to oxolinic acid, oxytetracycline, sulfamethoxazole-trimethoprim, and nitrofurantoin among heterotrophic bacteria, including human and fish pathogens, in two freshwater eel farms was investigated. High levels of individual- and multiple-drug-resistant bacteria were detected, although sampling events were not correlated with clinical outbreaks and drug therapy.     

16S rRNA Phylogeny of Sponge-Associated Cyanobacteria

Phylogenetic analyses of 16S rRNA sequences of sponge-associated cyanobacteria showed them to be polyphyletic, implying that they derived from multiple independent symbiotic events. Most of the symbiont sequences were affiliated to a group of Synechococcus and Prochlorococcus species. However, other symbionts were related to different groups, such as the Oscillatoriales.     

AmyA, an α-Amylase with β-Cyclodextrin-Forming Activity, and AmyB from the Thermoalkaliphilic Organism Anaerobranca gottschalkii: Two α-Amylases Adapted to Their Different Cellular Localizations

Two α-amylase genes from the thermophilic alkaliphile Anaerobranca gottschalkii were cloned, and the corresponding enzymes, AmyA and AmyB, were investigated after purification of the recombinant proteins. Based on their amino acid sequences, AmyA is proposed to be a lipoprotein with extracellular localization and thus is exposed to the alkaline milieu, while AmyB apparently represents a cytoplasmic enzyme. The amino acid sequences of both enzymes bear high similarity to those of GHF13 proteins. The different cellular localizations of AmyA and AmyB are reflected in their physicochemical properties. The alkaline pH optimum (pH 8), as well as the broad pH range, of AmyA activity (more than 50% activity between pH 6 and pH 9.5) mirrors the conditions that are encountered by an extracellular enzyme exposed to the medium of A. gottschalkii, which grows between pH 6 and pH 10.5. AmyB, on the other hand, has a narrow pH range with a slightly acidic pH optimum at 6 to 6.5, which is presumably close to the pH in the cytoplasm. Also, the intracellular AmyB is less tolerant of high temperatures than the extracellular AmyA. While AmyA has a half-life of 48 h at 70°C, AmyB has a half-life of only about 10 min at that temperature, perhaps due to the lack of stabilizing constituents of the cytoplasm. AmyA and AmyB were very similar with respect to their substrate specificity profiles, clearly preferring amylose over amylopectin, pullulan, and glycogen. Both enzymes also hydrolyzed α-, β-, and γ-cyclodextrin. Very interestingly, AmyA, but not AmyB, displayed high transglycosylation activity on maltooligosaccharides and also had significant β-cyclodextrin glycosyltransferase (CGTase) activity. CGTase activity has not been reported for typical α-amylases before. The mechanism of cyclodextrin formation by AmyA is unknown.