Bacterial collagenases are metalloproteinases involved in the degradation of the extracellular matrices of animal cells, due to their ability to digest native collagen. These enzymes are important virulence factors in a variety of pathogenic bacteria. Nonetheless, there is a lack of scientific consensus for a proper and well-defined classification of these enzymes and a vast controversy regarding the correct identification of collagenases. Clostridial collagenases were the first ones to be identified and characterized and are the reference enzymes for comparison of newly discovered collagenolytic enzymes. In this review we present the most recent data regarding bacterial collagenases and overview the functional and structural diversity of bacterial collagenases. An overall picture of the molecular diversity and distribution of these proteins in nature will also be given. Particular aspects of the different proteolytic activities will be contextualized within relevant areas of application, mainly biotechnological processes and therapeutic uses. At last, we will present a new classification guide for bacterial collagenases that will allow the correct and straightforward classification of these enzymes.
This research studies the relationship between six dimensions of leaders' emotional intelligence and two dimensions of employee creativity. A sample of 138 managers from 66 organizations reported on their own emotional intelligence and the creativity of their teams. Our results point out two main findings: (a) leaders' emotional intelligence explains significant variance of both creativity dimensions; (b) emotional intelligence dimensions with higher predictive power are self-control against criticism and empathy. The findings suggest that emotionally intelligent leaders behave in ways that stimulate the creativity of their teams.
Botryosphaeria sarmentorum sp. nov. and B. iberica sp. nov. are described and illustrated. These two species are unusual in this genus because of their brown, 1-septate ascospores. Phylogenetic analysis based on ITS and EF1-alpha sequences place them within the clade containing species with Fusicoccum anamorphs. The brown, 1-septate conidia, however, do not conform to Fusicoccum. Therefore phylogenetically and morphologically the anamorphs of these two species belong in a genus distinct from any of the currently accepted anamorph genera assigned to Botryosphaeria. Through a study of the type species of Dothiorella this genus is resurrected to accommodate anamorphs of Botryosphaeria with brown, 1-septate conidia. Botryosphaeria sarmentorum is shown to be the teleomorph of Diplodia sarmentorum, which in turn is transferred to Dothiorella. Otthia quercus is transferred to Botryosphaeria as B. quercicola nom. nov.
The thermal decomposition of cork has been studied by Fourier transform infrared (FTIR) spectroscopy and 13C solid-state nuclear magnetic resonance (NMR) spectroscopy with cross-polarization and magic-angle spinning (CP-MAS), high-power 'H decoupling (HPDEC) and cross-polarization depolarization-polarization (CPDP). Waxes and other soluble components of cork begin to decompose at ca. 150°C. This is accompanied by partial decomposition of suberin, probably initiated at the points of attachment to the cell wall. The carbohydrates begin to decompose at ca. 200°C. The decomposition of lignin begins at 250-3OO"C, while suberin undergoes further degradation. Significant amounts of coke are formed in the process. At 400°C cork has been transformed into coke with traces of partially decomposed suberin. The thermal decomposition of cork is dependent on the calcination time, particularly in the 200-350°C range.
The volatile compounds of cork were studied by gas chromatography and
combined gas chromatography−high-resolution mass spectrometry using simultaneous
distillation−extraction to prepare
the samples. To assess the origin of the volatiles, three
different types of samples were analyzed:
“normal”, attacked by Armillaria mellea, and infested by
molds. The study of the volatiles of these
different types of corks allowed the identification of the chemical
modifications which may occur in
cork polymers. The cork attacked by A.
mellea showed higher amounts of phenols,
vanillin,
benzaldehyde, benzyl alcohol, and chlorinated compounds than normal
cork; this may indicate lignin
degradation. The cork infested by molds contained higher levels of
3-methyl-1-butanol, 1-octen-3-ol, 1-octanol, 2-methylisoborneol, chlorinated compounds, and methyl
ketones. These components
resulting from microbial metabolism were also present in cork attacked
by A. mellea. The use of
cork attacked by A. mellea is not recommended in the
manufacture of cork stoppers, since these
types of cork have volatile compounds likely to cause off-flavors in
wine. For the same reason it is
important to reduce the likelihood of mold development during the
standing period.
Keywords: “Normal” cork; Armillaria mellea; molds; volatile
components; musty and moldy odors
Carbapenems are last-resort antibiotics to handle serious infections caused by multiresistant bacteria. The incidence of resistance to these antibiotics has been increasing and new resistance mechanisms have emerged. The dissemination of carbapenem resistance in the environment has been overlooked. The main goal of this research was to assess the prevalence and diversity of carbapenem-resistant bacteria in riverine ecosystems. The presence of frequently reported carbapenemase-encoding genes was inspected. The proportion of imipenem-resistant bacteria was on average 2.24 CFU/ml. Imipenem-resistant strains (n=110) were identified as Pseudomonas spp., Stenotrophomonas maltophilia, Aeromonas spp., Chromobacterium haemolyticum, Shewanella xiamenensis, and members of Enterobacteriaceae. Carbapenem-resistant bacteria were highly resistant to other beta-lactams such as quinolones, aminoglycosides, chloramphenicol, tetracyclines, and sulfamethoxazole/trimethoprim. Carbapenem resistance was mostly associated with intrinsically resistant bacteria. As intrinsic resistance mechanisms, we have identified the blaCphA gene in 77.3% of Aeromonas spp., blaL1 in all S. maltophilia, and blaOXA-48-like in all S. xiamenensis. As acquired resistance mechanisms, we have detected the blaVIM-2 gene in six Pseudomonas spp. (5.45%). Integrons with gene cassettes encoding resistance to aminoglycosides (aacA and aacC genes), trimethoprim (dfrB1b), and carbapenems (blaVIM-2) were found in Pseudomonas spp. Results suggest that carbapenem resistance dissemination in riverine ecosystems is still at an early stage. Nevertheless, monitoring these aquatic compartments for the presence of resistance genes and its host organisms is essential to outline strategies to minimize resistance dissemination.
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