A quantitative trait locus involved in maize yield is tightly associated to the r1 gene on the long arm of chromosome 10

We produced and studied for 3?years two synthetic populations of maize differing in their constitution only for the selected alleles present at the red color 1 (r1) locus (R-sc vs. r?Cr). r1 is a regulatory gene conferring anthocyanin pigmentation in different tissues: the R-sc allele confers pigmentation only in the aleurone seed layer, while the r?Cr allele confers pigmentation in several tissues such as root, silk and anther but the seed is colourless. The colourless population (r?Cr/r?Cr) was characterized by improved agronomic features, such as ear weight and plant height, compared with the R-sc/R-sc coloured population. This finding was confirmed by studying single F4 R/r families where the presence of the r?Cr allele conferred positive features, acting as a dominant trait. Quantitative trait locus (QTL) analysis performed using molecular markers on the long arm of chromosome 10 (bin 10.06), where the r1 gene maps, identified a QTL map position for plant height tightly associated to the r1 gene. Thus the r1 gene may represent a major QTL or it could be closely linked to another gene involved in the agronomic performance of the two populations studied.     

Chemical characterization (GC/MS and NMR Fingerprinting) and bioactivities of South-African Pelargonium capitatum (L.) L' Her. (Geraniaceae) essential oil

Chemical fingerprinting of commercial Pelargonium capitatum (Geraniaceae) essential oil samples of south African origin was performed by GC, GC/MS, and (13) C- and (1) H-NMR. Thirty-seven compounds were identified, among which citronellol (32.71%) and geraniol (19.58%) were the most abundant. NMR Spectra of characteristic chemicals were provided. Broad-spectrum bioactivity properties of the oil were evaluated and compared with those of commercial Thymus vulgaris essential oil with the aim to obtain a functional profile in terms of efficacy and safety. P. capitatum essential oil provides a good performance as antimicrobial, with particular efficacy against Candida albicans strains. Antifungal activity performed against dermatophyte and phytopathogen strains revealed the latter as more sensitive, while antibacterial activity was not remarkable against both Gram-positive and Gram-negative bacteria. P. capitatum oil provided a lower antioxidant activity (IC(50) ) than that expressed by thyme essential oil, both in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. Results in photochemiluminescence (PCL) assay were negligible. To test the safety aspects of P. capitatum essential oil, mutagenic and toxicity properties were assayed by Ames test, with and without metabolic activation. Possible efficacy of P. capitatum essential oil as mutagenic protective agent against NaN(3) , 2-nitrofluorene, and 2-aminoanthracene was also assayed, providing interesting and significant antigenotoxic properties.     

Migratory orientation of sedge warblers (Acrocephalus schoenobaenus) in relation to eating and exploratory behaviour

Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds’ personalities.We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released.Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered.Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present.Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked.Personality aspects may influence the individuals’ ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds’ performance in apparently unrelated experiments.     

Cytochemical and molecular characteristics of the process of cornification during feather morphogenesis

Feathers are the most complex epidermal derivatives among vertebrates. The present review deals with the origin of feathers from archosaurian reptiles, the cellular and molecular aspects of feather morphogenesis, and focus on the synthesis of keratins and associated proteins. Feathers consist of different proteins among which exists a specialized group of small proteins called beta-keratins. Genes encoding these proteins in the chick genome are distributed in different chromosomes, and most genes encode for feather keratins. The latter are here recognized as proteins associated with the keratins of intermediate filaments, and functionally correspond to keratin-associated proteins of hairs, nails and horns in mammals. These small proteins possess unique properties, including resistance and scarce elasticity, and were inherited and modified in feathers from ancestral proteins present in the scales of archosaurian progenitors of birds. The proteins share a common structural motif, the core box, which was present in the proteins of the reptilian ancestors of birds. The core box allows the formation of filaments with a different molecular mechanism of polymerization from that of alpha-keratins. Feathers evolved after the establishment of a special morphogenetic mechanism gave rise to barb ridges. During development, the epidermal layers of feathers fold to produce barb ridges that produce the ramified structure of feathers. Among barb ridge cells, those of barb and barbules initially accumulate small amounts of alpha-keratins that are rapidly replaced by a small protein indicated as “feather keratin”. This 10 kDa protein becomes the predominant form of corneous material of feathers. The main characteristics of feather keratins, their gene organization and biosynthesis are similar to those of their reptilian ancestors. Feather keratins allow elongation of feather cells among supportive cells that later degenerate and leave the ramified microstructure of barbs. In downfeathers, barbs are initially independent and form plumulaceous feathers that rest inside a follicle. Stem cells remain in the follicle and are responsible for the regeneration of pennaceous feathers. New barb ridges are produced and they merge to produce a rachis and a flat vane. The modulation of the growth pattern of barb ridges and their fusion into a rachis give rise to a broad variety of feather types, including asymmetric feathers for flight. Feather morphogenesis suggests possible stages for feather evolution and diversification from hair-like outgrowths of the skin found in fossils of pro-avian archosaurians.     

Impact of antigen presentation on TCR modulation and cytokine release: implications for detection and sorting of antigen-specific CD8+ T cells using HLA-A2 wild-type or HLA-A2 mutant tetrameric complexes

Soluble MHC class I molecules loaded with antigenic peptides are available either to detect and to enumerate or, alternatively, to sort and expand MHC class I-restricted and peptide-reactive T cells. A defined number of MHC class I/peptide complexes can now be implemented to measure T cell responses induced upon Ag-specific stimulation, including CD3/CD8/zeta-chain down-regulation, pattern, and quantity of cytokine secretion. As a paradigm, we analyzed the reactivity of a Melan-A/MART-1-specific and HLA-A2-restricted CD8(+) T cell clone to either soluble or solid-phase presented peptides, including the naturally processed and presented Melan-A/MART-1 peptide AAGIGILTV or the peptide analog ELAGIGILTV presented either by the HLA-A2 wild-type (wt) or mutant (alanineright arrowvaline aa 245) MHC class I molecule, which reduces engagement of the CD8 molecule with the HLA-A2 heavy chain. Soluble MHC class I complexes were used as either monomeric or tetrameric complexes. Soluble monomeric MHC class I complexes, loaded with the Melan-A/MART-1 peptide, resulted in CD3/CD8 and TCR zeta-chain down-regulation, but did not induce measurable cytokine release. In general, differences pertaining to CD3/CD8/zeta-chain regulation and cytokine release, including IL-2, IFN-gamma, and GM-CSF, were associated with 1) the format of Ag presentation (monomeric vs tetrameric MHC class I complexes), 2) wt vs mutant HLA-A2 molecules, and 3) the target Ag (wt vs analog peptide). These differences are to be considered if T cells are exposed to recombinant MHC class I Ags loaded with peptides implemented for detection, activation, or sorting of Ag-specific T cells.     

Arterially perfused neurosphere-derived cells distribute outside the ischemic core in a model of transient focal ischemia and reperfusion in vitro

BACKGROUND: Treatment with neural stem cells represents a potential strategy to improve functional recovery of post-ischemic cerebral injury. The potential benefit of such treatment in acute phases of human ischemic stroke depends on the therapeutic viability of a systemic vascular delivery route. In spite of the large number of reports on the beneficial effects of intracerebral stem cells injection in experimental stroke, very few studies demonstrated the effectiveness of the systemic intravenous delivery approach. METODOLOGY/PRINCIPAL FINDINGS: We utilized a novel in vitro model of transient focal ischemia to analyze the brain distribution of neurosphere-derived cells (NCs) in the early 3 hours that follow transient occlusion of the medial cerebral artery (MCA). NCs obtained from newborn C57/BL6 mice are immature cells with self-renewal properties that could differentiate into neurons, astrocytes and oligodendrocytes. MCA occlusion for 30 minutes in the in vitro isolated guinea pig brain preparation was followed by arterial perfusion with 1x10(6) NCs charged with a green fluorescent dye, either immediately or 60 minutes after reperfusion onset. Changes in extracellular pH and K(+) concentration during and after MCAO were measured through ion-sensitive electrodes. CONCLUSION/SIGNIFICANCE: It is demonstrated that NCs injected through the vascular system do not accumulate in the ischemic core and preferentially distribute in non-ischemic areas, identified by combined electrophysiological and morphological techniques. Direct measurements of extracellular brain ions during and after MCA occlusion suggest that anoxia-induced tissue changes, such as extracellular acidosis, may prevent NCs from entering the ischemic area in our in vitro model of transitory focal ischemia and reperfusion suggesting a role played by the surrounding microenviroment in driving NCs outside the ischemic core. These findings strongly suggest that the potential beneficial effect of NCs in experimental focal brain ischemia is not strictly dependent on their homing into the ischemic region, but rather through a bystander mechanism possibly mediated by the release of neuroprotective factors in the peri-infarct region.     

A comparative study on axial coordination and ligand binding in ferric mini myoglobin and horse heart myoglobin

The absorption and resonance Raman spectra and the azide binding kinetics of ferric horse heart myoglobin (Mb) and mini myoglobin (a chemically truncated form of horse heart Mb containing residues 32-139) have been compared. The steady-state spectra show that an additional six-coordinated low-spin form (not present in entire horse heart Mb, which is purely six-coordinated high spin) predominates in mini Mb. The distal histidine is possibly the sixth ligand in this species. The presence of two species corresponds to a kinetic biphasicity for mini Mb that is not observed for horse heart Mb. Azide binds to horse heart Mb much more slowly than to sperm whale Mb. This difference may result from a sterically hindered distal pocket in horse heart Mb. In both cases, the rate constants level off at high azide concentrations, implying the existence of a rate-limiting step (likely referable to the dissociation of the axial sixth ligand). The faster rate constant of mini Mb is similar to that of sperm whale Mb, whereas the slower one is similar to that of entire horse heart Mb.     

Origin,diversity, and biogeography of Antarctic scale worms (Polychaeta: Polynoidae): a wide‐scale barcoding approach

The Antarctic marine environment hosts diversified and highly endemic benthos owing to its unique geologic and climatic history. Current warming trends have increased the urgency of understanding Antarctic species history to predict how environmental changes will impact ecosystem functioning. Antarctic benthic lineages have traditionally been examined under three hypotheses: (1) high endemism and local radiation, (2) emergence of deep‐sea taxa through thermohaline circulation, and (3) species migrations across the Polar Front. In this study, we investigated which hypotheses best describe benthic invertebrate origins by examining Antarctic scale worms (Polynoidae). We amassed 691 polynoid sequences from the Southern Ocean and neighboring areas: the Kerguelen and Tierra del Fuego (South America) archipelagos, the Indian Ocean, and waters around New Zealand. We performed phylogenetic reconstructions to identify lineages across geographic regions, aided by mitochondrial markers cytochrome c oxidase subunit I (Cox1) and 16S ribosomal RNA (16S). Additionally, we produced haplotype networks at the species scale to examine genetic diversity, biogeographic separations, and past demography. The Cox1 dataset provided the most illuminating insights into the evolution of polynoids, with a total of 36 lineages identified. Eunoe sp. was present at Tierra del Fuego and Kerguelen, in favor of the latter acting as a migration crossroads. Harmothoe fuligineum, widespread around the Antarctic continent, was also present but isolated at Kerguelen, possibly resulting from historical freeze–thaw cycles. The genus Polyeunoa appears to have diversified prior to colonizing the continent, leading to the co‐occurrence of at least three cryptic species around the Southern and Indian Oceans. Analyses identified that nearly all populations are presently expanding following a bottleneck event, possibly caused by habitat reduction from the last glacial episodes. Findings support multiple origins for contemporary Antarctic polynoids, and some species investigated here provide information on ancestral scenarios of (re)colonization. First, it is apparent that species collected from the Antarctic continent are endemic, as the absence of closely related species in the Kerguelen and Tierra del Fuego datasets for most lineages argues in favor of Hypothesis 1 of local origin. Next, Eunoe sp. and H. fuligineum, however, support the possibility of Kerguelen and other sub‐Antarctic islands acting as a crossroads for larvae of some species, in support of Hypothesis 3. Finally, the genus Polyeunoa, conversely, is found at depths greater than 150 m and may have a deep origin, in line with Hypothesis 2. These “non endemic” groups, nevertheless, have a distribution that is either north or south of the Antarctic Polar Front, indicating that there is still a barrier to dispersal, even in the deep sea.