Psychrophilic yeasts from worldwide glacial habitats: diversity, adaptation strategies and biotechnological potential

Glacial habitats (cryosphere) include some of the largest unexplored and extreme biospheres on Earth. These habitats harbor a wide diversity of psychrophilic prokaryotic and eukaryotic microorganisms. These highly specialized microorganisms have developed adaptation strategies to overcome the direct and indirect life-endangering influence of low temperatures. For many years Antarctica has been the geographic area preferred by microbiologists for studying the diversity of psychrophilic microorganisms (including yeasts). However, there have been an increasing number of studies on psychrophilic yeasts sharing the non-Antarctic cryosphere. The present paper provides an overview of the distribution and adaptation strategies of psychrophilic yeasts worldwide. Attention is also focused on their biotechnological potential, especially on their exploitation as a source of cold-active enzymes and for bioremediation purposes.     

Phytochemical variability during vegetation of Chamerion angustifolium (L.) Holub genotypes derived from in vitro cultures

The purpose of the study was to evaluate Chamerion angustifolium (L.) Holub genotypes for preliminary selection and further breeding programs aimed at obtaining a suitable industrial form for the pharmaceutical applications. Clonally propagated plants representing 10 genotypes of Ch. angustifolium were regenerated under in vitro conditions, hardened and planted in the field. Studies included an evaluation of shoot proliferation, phytochemical assessment of in vitro and ex vitro plants as well as investigations of intraspecies variability regarding four phenological stages: vegetative, beginning of blooming, full blooming, and green fruit phases. Quantitative and qualitative analyses of bioactive compounds were performed using high-performance liquid chromatography coupled with diode array detector and tandem mass spectrometer (HPLC–DAD–MS/MS) and high-performance liquid chromatography (HPLC) methods. The efficiency of shoot multiplication varied between genotypes from 8.12 to 21.48 shoots per explant. A high reproduction rate (>?20 shoots per explant) was recorded for four lines (PL_45, PL_44, PL_58, DE_2). Plants grown in vitro synthesized oenothein B (11.2–22.3 mg g^?1 DW) and caffeic acid derivatives. Plants harvested from field contained the full spectrum of polyphenols characteristic for this species, and oenothein B and quercetin 3-O-glucuronide were the most abundant. The maximal content of oenothein B was determined in the vegetative phase of fireweed, while some flavonoids were found in the highest amount in full blooming phase. The results of analysis of variance indicated significant differences among genotypes in oenothein B, 3-O-caffeoylquinic acid and flavonoids accumulation in four phenological phases. PL_44 plants were characterized by high content of oenothein B and quercetin 3-O-glucuronide as well as a relatively high level of other flavonoids. Based on our phytochemical and micropropagation studies, PL_44 genotype was the best candidate for early selection and further breeding programs.

     

Absence of Tangentially Migrating Glutamatergic Neurons in the Developing Avian Brain

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Trends of karyotypical evolution in the pearl cichlid,Geophagus brasiliensis,from southern Brazil

Chromosomal rearrangements such as inversions can facilitate speciation even in the presence of gene flow. The present study aims to analyze the karyotypic variation in six populations of Geophagus brasiliensis from southern Brazil. All specimens showed 2n = 48 chromosomes, but three karyotypes were found to have one, two or three pairs of submetacentric chromosomes. Although G. brasiliensis did not exhibit variation in the diploid number, it presented a wide interpopulational variation mainly regarding the karyotype formula and specific chromosomal markers. Differences in the location of the major and minor rDNA loci were observed among the populations. Moreover, different patterns were observed in the distribution of the constitutive heterochromatin, presenting intra- and interpopulational variation. This supports the hypothesis that this taxon represents a complex species or that cryptic species are included in this group, indicating a possibleprocess of sympatric speciation. By potentially restricting gene flow between heterokaryotypes, the segregating chromosome rearrangements we describe for G. brasiliensis may play a role in diversification in this species complex.     

The Fate of Threatened Coastal Dune Habitats in Italy under Climate Change Scenarios

Coastal dunes worldwide harbor threatened habitats characterized by high diversity in terms of plant communities. In Italy, recent assessments have highlighted the insufficient state of conservation of these habitats as defined by the EU Habitats Directive. The effects of predicted climate change could have dramatic consequences for coastal environments in the near future. An assessment of the efficacy of protection measures under climate change is thus a priority. Here, we have developed environmental envelope models for the most widespread dune habitats in Italy, following two complementary approaches: an “indirect” plant-species-based one and a simple “direct” one. We analyzed how habitats distribution will be altered under the effects of two climate change scenarios and evaluated if the current Italian network of protected areas will be effective in the future after distribution shifts. While modeling dune habitats with the “direct” approach was unsatisfactory, “indirect” models had a good predictive performance, highlighting the importance of using species’ responses to climate change for modeling these habitats. The results showed that habitats closer to the sea may even increase their geographical distribution in the near future. The transition dune habitat is projected to remain stable, although mobile and fixed dune habitats are projected to lose most of their actual geographical distribution, the latter being more sensitive to climate change effects. Gap analysis highlighted that the habitats’ distribution is currently adequately covered by protected areas, achieving the conservation target. However, according to predictions, protection level for mobile and fixed dune habitats is predicted to drop drastically under the climate change scenarios which we examined. Our results provide useful insights for setting management priorities and better addressing conservation efforts to preserve these threatened habitats in future.     

The role of aminoglycoside--modifying enzymes in resistance of Gram-negative rods

The aim of the study was to evaluate the aminoglycoside resistance of Gram-negative bacilli isolated from patients. To the examination 35 strains of Enterobacteriaceae and 18 of non-fermentative bacteria were included. Resistance to aminoglycosides (gentamicin (G), netilmicin (Nt), tobramycin (T), amikacin (A), kanamycin (K), neomycin (N)) was established by disk diffusion method. Interpretation of enzymatic mechanisms was performed by Livermore. The most common enzymes AAC(6')I were found in Enterobacteriaceae group (mostly in E. cloaceae and P. mirabilis) and AAC(3') and in non-fermentative bacteria: AAC(6')I in P. aeruginosa and APH(3')VI and AAC(3')I in A. baumanii. The most frequent phenotype was resistance to six antibiotics (G, Nt, T, A, K, N) Resistance rates were high for gentamicin (>70 %) in both groups and amikacin (88,89 %) in non-fermentatives.     

Human cytomegalovirus (HCMV) infection of endothelial cells promotes naive monocyte extravasation and transfer of productive virus to enhance hematogenous dissemination of HCMV

Human cytomegalovirus (HCMV) pathogenesis is dependent on the hematogenous spread of the virus to host tissue. While data suggest that infected monocytes are required for viral dissemination from the blood to the host organs, infected endothelial cells are also thought to contribute to this key step in viral pathogenesis. We show here that HCMV infection of endothelial cells increased the recruitment and transendothelial migration of monocytes. Infection of endothelial cells promoted the increased surface expression of cell adhesion molecules (intercellular cell adhesion molecule 1, vascular cell adhesion molecule 1, E-selectin, and platelet endothelial cell adhesion molecule 1), which were necessary for the recruitment of na?ve monocytes to the apical surface of the endothelium and for the migration of these monocytes through the endothelial cell layer. As a mechanism to account for the increased monocyte migration, we showed that HCMV infection of endothelial cells increased the permeability of the endothelium. The cellular changes contributing to the increased permeability and increased na?ve monocyte transendothelial migration include the disruption of actin stress fiber formation and the decreased expression of lateral junction proteins (occludin and vascular endothelial cadherin). Finally, we showed that the migrating monocytes were productively infected with the virus, documenting that the virus was transferred to the migrating monocyte during passage through the lateral junctions. Together, our results provide evidence for an active role of the infected endothelium in HCMV dissemination and pathogenesis.     

Proposed Classification of Auriculotemporal Nerve,Based on the Root System

The topography of the auriculotemporal nerve (ATN) root system is the main criterion of this nerve classification. Previous publications indicate that ATN may have between one and five roots. Most common is a one- or two-root variant of the nerve structure. The problem of many publications is the inconsistency of nomenclature which concerns the terms “roots”, “connecting branches”, or “branches” that are used to identify the same structures. This study was performed on 80 specimens (40 adults and 40 fetuses) to propose a classification based on: (i) the number of roots, (ii) way of root division, and (iii) configuration of interradicular fibers that form the ATN trunk. This new classification is a remedy for inconsistency of nomenclature of ATN in the infratemporal fossa. This classification system has proven beneficial when organizing all ATN variants described in previous studies and could become a helpful tool for surgeons and dentists. Examination of ATN from the infratemporal fossa of fetuses (the youngest was at 18 weeks gestational age) showed that, at that stage, the nerve is fully developed.