Dimorphic and yeast-like mutants of the genusCephalosporium Cda

A series of mutants, in which the mycelial type of growth gradually changes to the dimorphic and permanent yeast-like forms, were isolated from cultures ofCephalosporium sp. subjected to UV radiation. The intermediate stage between the mycelial and dimorphic strains (mutants 2/29 and 2/R) is characterized by the absence of aerial hyphae, ability to form conidiophores inside agar and by polymorphism of conidia. The Y-M transformation of two dimorphic mutants obtained from the 2/R mutant depends on temperature. Another mutant isolated from the 2/29 strain was found to form the mycelial phase only when osmolarity of the medium increased. At 22°C the transformation of all three dimorphic strains was influenced by the carbon source: the Y phase predominated in glucose-containing media, the M phase predominated in media with amino acids or citrate serving as carbon sources. Another mutant (2/7R) was found to grow permanently in the Y phase and was not influenced by temperature, osmolarity of the medium and by the carbon source. It is assumed that the dimorphism of the mutants is caused by a conformational mutation inhibiting the apical growth. This mutation can be phenotypically reversed by some factors of the environment.     

Effect of Cattle on Salmonella Carriage,Diversity and Antimicrobial Resistance in Free-Ranging Wild Boar (Sus scrofa) in Northeastern Spain

Salmonella is distributed worldwide and is a pathogen of economic and public health importance. As a multi-host pathogen with a long environmental persistence, it is a suitable model for the study of wildlife-livestock interactions. In this work, we aim to explore the spill-over of Salmonella between free-ranging wild boar and livestock in a protected natural area in NE Spain and the presence of antimicrobial resistance. Salmonella prevalence, serotypes and diversity were compared between wild boars, sympatric cattle and wild boars from cattle-free areas. The effect of age, sex, cattle presence and cattle herd size on Salmonella probability of infection in wild boars was explored by means of Generalized Linear Models and a model selection based on the Akaike’s Information Criterion. Prevalence was higher in wild boars co-habiting with cattle (35.67%, CI 95% 28.19–43.70) than in wild boar from cattle-free areas (17.54%, CI 95% 8.74–29.91). Probability of a wild boar being a Salmonella carrier increased with cattle herd size but decreased with the host age. Serotypes Meleagridis, Anatum and Othmarschen were isolated concurrently from cattle and sympatric wild boars. Apart from serotypes shared with cattle, wild boars appear to have their own serotypes, which are also found in wild boars from cattle-free areas (Enteritidis, Mikawasima, 4:b:- and 35:r:z35). Serotype richness (diversity) was higher in wild boars co-habiting with cattle, but evenness was not altered by the introduction of serotypes from cattle. The finding of a S. Mbandaka strain resistant to sulfamethoxazole, streptomycin and chloramphenicol and a S. Enteritidis strain resistant to ciprofloxacin and nalidixic acid in wild boars is cause for public health concern.     

Genetic evidence for the requirement of the endocytic pathway in the uptake of coenzyme Q6 in Saccharomyces cerevisiae

Coenzyme Q is an isoprenylated benzoquinone lipid that functions in respiratory electron transport and as a lipid antioxidant. Dietary supplementation with Q is increasingly used as a therapeutic for treatment of mitochondrial and neurodegenerative diseases, yet little is known regarding the mechanism of its uptake. As opposed to other yeast backgrounds, EG103 strains are unable to import exogenous Q₆ to the mitochondria. Furthermore, the distribution of exogenous Q₆ among endomembranes suggests an impairment of the membrane traffic at the level of the endocytic pathway. This fact was confirmed after the detection of defects in the incorporation of FM4-64 marker and CPY delivery to the vacuole. A similar effect was demonstrated in double mutant strains in Q₆ synthesis and several steps of endocytic process; those cells are unable to uptake exogenous Q₆ to the mitochondria and restore the growth on non-fermentable carbon sources. Additional data about the positive effect of peptone presence for exogenous Q₆ uptake support the hypothesis that Q₆ is transported to mitochondria through an endocytic-based system.     

Effects of Pre-Treatments with Abscisic Acid and/or Benzyladenine on Gas Exchange of French Bean, Sugar Beet, and Maize Leaves During Water Stress and After Rehydration

Net photosynthetic rate (P_N), transpiration rate (E), and stomatal conductance (g_s) during water stress and after rehydration were measured in Phaseolus vulgaris, Beta vulgaris, and Zea mays. Immediately before imposition of water stress by cessation of watering, plants were irrigated with water (control), 100 M abscisic acid (ABA), and/or 10 M N⁶-benzyladenine (BA). In all three species, application of ABA decreased g_s, E, and P_N already 1 h after application. However, during water stress g_s, E, and P_N in plants pre-treated with ABA remained higher than in plants pre-treated with water. Positive effects of ABA application were observed also after rehydration. In contrast, the effects of pre-treatment with BA were species-specific. While in bean plants BA application ameliorated negative effect of water stress, only very slight effects were observed in maize, and in sugar beet BA even aggravated the effects of water stress.     

Influence of the nitrogen source on the production and rheological properties of scleroglucan produced by Sclerotium rolfsii ATCC 201126

Scleroglucan production by Sclerotium rolfsii ATCC 201126 has been studied using nitrate or ammonium as nitrogen sources at several concentrations. In all the experiments carried out, both growth and production were modelled by an unstructured kinetic model using logistic and Luedeking–Piret equations for describing growth and production, respectively. The kinetic parameters for growth ( and Y_XN) and for production ( and ) were obtained by fitting the data to the model using the single-response non-linear regression technique by means of the algorithm of Marquardt coupled to a fourth-order Runge–Kutta algorithm. Biomass and scleroglucan production were higher when nitrate was the nitrogen source. Rheological properties of scleroglucan produced using nitrate as nitrogen source were studied and rheological parameters calculated, revealing similarity between this biopolymer and commercial scleroglucan.     

In silico studies of potential phosphoresidues in the human nucleophosmin/B23: its kinases and related biological processes

Human nucleophosmin/B23 is a phosphoprotein involved in ribosome biogenesis, centrosome duplication, cancer, and apoptosis. Its function, localization, and mobility within cells, are highly regulated by phosphorylation events. Up to 21 phosphosites of B23 have been experimentally verified even though the corresponding kinase is known only for seven of them. In this work, we predict the phosphorylation sites in human B23 using six kinase-specific servers (KinasePhos 2.0, PredPhospho, NetPhosK 1.0, PKC Scan, pkaPS, and MetaPredPS) plus DISPHOS 1.3, which is not kinase specific. The results were integrated with information regarding 3D structure and residue conservation of B23, as well as cellular localizations, cellular processes, signaling pathways and protein-protein interaction networks involving both B23 and each predicted kinase. Thus, all 40 potential phosphosites of B23 were predicted with significant score (>0.50) as substrates of at least one of 38 kinases. Thirteen of these residues are newly proposed showing high susceptibility of phosphorylation considering their solvent accessibility. Our results also suggest that the enzymes CDKs, PKC, CK2, PLK1, and PKA could phosphorylate B23 at higher number of sites than those previously reported. Furthermore, PDK, GSK3, ATM, MAPK, PKB, and CHK1 could mediate multisite phosphorylation of B23, although they have not been verified as kinases for this protein. Finally, we suggest that B23 phosphorylation is related to cellular processes such as apoptosis, cell survival, cell proliferation, and response to DNA damage stimulus, in which these kinases are involved. These predictions could contribute to a better understanding, as well as addressing further experimental studies, of B23 phosphorylation.     

Molecular characterization of American cockroach tropomyosin (Periplaneta americana allergen 7), a cross-reactive allergen

Inhalation of allergens produced by the American cockroach (Periplaneta americana) induces IgE Ab production and the development of asthma in genetically predisposed individuals. The cloning and expression in Escherichia coli of P. americana tropomyosin allergen have been achieved. The protein shares high homology with other arthropod tropomyosins (80% identity) but less homology with vertebrate ones (50% identity). The recombinant allergen was produced in E. coli as a nonfusion protein with a yield of 9 mg/l of bacterial culture. Both natural and recombinant tropomyosins were purified by isoelectric precipitation. P. americana allergen 1 (Per a 1) and Per a 7 (tropomyosin) are to date the only cross-reacting allergens found in cockroaches. ELISA and Western blot inhibition experiments, using natural and recombinant purified tropomyosins from shrimp and cockroach, showed that tropomyosin induced cross-reactivity of IgE from patients allergic to these allergens, suggesting that this molecule could be a common allergen among invertebrates.     

Molecular and morphological diversity of Trebouxia microalgae in sphaerothallioid Circinaria spp. lichens1

Three vagrant (Circinaria hispida, Circinaria gyrosa, and Circinaria sp. ‘paramerae’) and one crustose (semi‐vagrant, Circinaria sp. ‘oromediterranea’) lichens growing in very continental areas in the Iberian Peninsula were selected to study the phycobiont diversity. Mycobiont identification was checked using nrITS DNA barcoding: Circinaria sp. ‘oromediterranea’ and Circinaria sp. ‘paramerae’ formed a new clade. Phycobiont diversity was analyzed in 50 thalli of Circinaria spp. using nrITS DNA and LSU rDNA, with microalgae coexistence being found in all the species analyzed by Sanger sequencing. The survey of phycobiont diversity showed up to four different Trebouxia spp. as the primary phycobiont in 20 thalli of C. hispida, in comparison with the remaining Circinaria spp., where only one Trebouxia was the primary microalga. In lichen species showing coexistence, some complementary approaches are needed (454 pyrosequencing and/or ultrastructural analyses). Five specimens were selected for high‐throughput screening (HTS) analyses: 22 Trebouxia OTUs were detected, 10 of them not previously known. TEM analyses showed three different cell morphotypes (Trebouxia sp. OTU A12, OTU S51, and T. cretacea) whose ultrastructure is described here in detail for the first time. HTS revealed a different microalgae pool in each species studied, and we cannot assume a specific pattern between these pools and the ecological and/or morphological characteristics. The mechanisms involved in the selection of the primary phycobiont and the other microalgae by the mycobiont are unknown, and require complex experimental designs. The systematics of the genus Circinaria is not yet well resolved, and more analyses are needed to establish a precise delimitation of the species.