DNA barcoding of marine fishes from Saudi Arabian waters of the Gulf

We used the cytochrome oxidase subunit I (coI) gene DNA to barcode 117 endemic Gulf and cosmopolitan Indo–West Pacific fish species belonging to 54 families and 13 orders. Novel DNA barcodes were provided for 18 fish species (Trachinocephalus sp., Nematalosa sp., Herklotsichthys lossei, Upeneus doriae, Trachurus indicus, Apogonichthyoides taeniatus, Verulux cypselurus, Favonigobius sp., Suezichthus gracilis, Sillago sp., Brachirus orientalis, Pegusa sp., Lepidotrigla bispinosa, Lepidotrigla sp., Grammoplites suppositus, Hippichthys sp., Paramonacanthus sp. and Triacanthus sp.). The species delimitation analysis, conducted with Poisson tree processes– Bayesian PTP (PTP–bPTP) and nucleotide-divergence-threshold (NDT) models), found 137 and 119 entities respectively. Overall, NDT method, neighbour-joining species tree and the prior taxonomic assessment provided similar results. Among the 54 families considered, only 10 (Ariommatidae, Ephippidae, Leiognathidae, Nemipteridae, Plotosidae, Pomacanthidae, Pomacentridae, Priacanthidae and Rachycentridae) showed the occurrence of molecular diagnostic pure characters. The DNA barcoding database developed during this study will help ichthyologists to identify and resolve the taxonomic ambiguities they may encounter with the fishes occurring in The Gulf and throughout the region.     

Assessment of the Chemical Quality of Recreational Bathing Water in Argentina by Health Risk Analysis

Del Azul creek (Argentina) is a natural water body used for recreational bathing in which heavy metals and pesticides have been detected. The aim of the study is to estimate the probabilistic non-cancer and cancer risks by recreational bathing, applying U.S. Environmental Protection Agency models for aggregated (exposure through accidental oral intake of water and dermal contact) and cumulative risks (combined exposure to groups of substances) for bathers of 5, 10, 15, and 20 years old. Bathing in Del Azul creek does not generate risks at the concentrations and the exposure scenarios considered. Cypermethrin and arsenic and heptachlor were the riskiest non-cancer and cancer substances, respectively. Our study highlights the importance of considering both routes of exposure because of the great significance of the dermal route and because of the variability of population characteristics, as it has been stated in other studies. These considerations are highly significant for Argentina, where the quality of recreational water for other than microbiological causes is frequently evaluated based only on the harmful oral intake and applied to a hypothetical individual representative of the population.     

Assessing the Threat of Amphibian Chytrid Fungus in the Albertine Rift: Past,Present and Future

Batrachochytrium dendrobatidis (Bd), the cause of chytridiomycosis, is a pathogenic fungus that is found worldwide and is a major contributor to amphibian declines and extinctions. We report results of a comprehensive effort to assess the distribution and threat of Bd in one of the Earth’s most important biodiversity hotspots, the Albertine Rift in central Africa. In herpetological surveys conducted between 2010 and 2014, 1018 skin swabs from 17 amphibian genera in 39 sites across the Albertine Rift were tested for Bd by PCR. Overall, 19.5% of amphibians tested positive from all sites combined. Skin tissue samples from 163 amphibians were examined histologically; of these two had superficial epidermal intracorneal fungal colonization and lesions consistent with the disease chytridiomycosis. One amphibian was found dead during the surveys, and all others encountered appeared healthy. We found no evidence for Bd-induced mortality events, a finding consistent with other studies. To gain a historical perspective about Bd in the Albertine Rift, skin swabs from 232 museum-archived amphibians collected as voucher specimens from 1925–1994 were tested for Bd. Of these, one sample was positive; an Itombwe River frog (Phrynobatrachus asper) collected in 1950 in the Itombwe highlands. This finding represents the earliest record of Bd in the Democratic Republic of Congo. We modeled the distribution of Bd in the Albertine Rift using MaxEnt software, and trained our model for improved predictability. Our model predicts that Bd is currently widespread across the Albertine Rift, with moderate habitat suitability extending into the lowlands. Under climatic modeling scenarios our model predicts that optimal habitat suitability of Bd will decrease causing a major range contraction of the fungus by 2080. Our baseline data and modeling predictions are important for comparative studies, especially if significant changes in amphibian health status or climactic conditions are encountered in the future.     

The frequency-dependent Wright–Fisher model: diffusive and non-diffusive approximations

We study a class of processes that are akin to the Wright–Fisher model, with transition probabilities weighted in terms of the frequency-dependent fitness of the population types. By considering an approximate weak formulation of the discrete problem, we are able to derive a corresponding continuous weak formulation for the probability density. Therefore, we obtain a family of partial differential equations for the evolution of the probability density, and which will be an approximation of the discrete process in the joint large population, small time-steps and weak selection limit. If the fitness functions are sufficiently regular, we can recast the weak formulation in a more standard formulation, without any boundary conditions, but supplemented by a number of conservation laws. The equations in this family can be purely diffusive, purely hyperbolic or of convection–diffusion type, with frequency dependent convection. The particular outcome will depend on the assumed scalings. The diffusive equations are of the degenerate type; using a duality approach, we also obtain a frequency dependent version of the Kimura equation without any further assumptions. We also show that the convective approximation is related to the replicator dynamics and provide some estimate of how accurate is the convective approximation, with respect to the convective-diffusion approximation. In particular, we show that the mode, but not the expected value, of the probability distribution is modelled by the replicator dynamics. Some numerical simulations that illustrate the results are also presented.     

Visually inexperienced chicks exhibit spontaneous preference for biological motion patterns

When only a small number of points of light attached to the torso and limbs of a moving organism are visible, the animation correctly conveys the animal's activity. Here we report that newly hatched chicks, reared and hatched in darkness, at their first exposure to point-light animation sequences, exhibit a spontaneous preference to approach biological motion patterns. Intriguingly, this predisposition is not specific for the motion of a hen, but extends to the pattern of motion of other vertebrates, even to that of a potential predator such as a cat. The predisposition seems to reflect the existence of a mechanism in the brain aimed at orienting the young animal towards objects that move semi-rigidly (as vertebrate animals do), thus facilitating learning, i.e., through imprinting, about their more specific features of motion.     

Spot overlapping in two-dimensional maps: a serious problem ignored for much too long

In the analysis of a neuroblastoma xenograft implanted in mice using two-dimensional maps, some 85 proteins were found to be up- or down-regulated (out of a total of 264 detected by a medium-sensitivity colloidal Coomassie stain). When these spots were eluted and analysed by mass spectrometry in a quadrupole time of flight mass spectrometer, a number of spots were found to be envelopes of different polypeptide chains. Out of a total of 74 proteins identified, 52 (71%) were found to be singlets, 14 (19%) were doublets, 6 (8%) were triplets, 1 was a quadruplet and 1 a quintuplet. Analysis of the DeltapI and DeltaMr of all species contained in a single gel segment eluted helped point out potential errors in protein identification. This was a unique case, in that very minute bioptic sample loads were applied to the gel. In normal cases, where sample loads of ca. 1 mg of total protein are applied and typically at least 1000 spots are visualised, the singlets will be the minority, rarely exceeding 30% of all spots analysed. The experimental data on the abundance of overlapping spots were in excellent agreement with theoretical data calculated on the basis of the statistical theory of spot overlapping, originally proposed by Davis and further developed by some of the authors. Ways and means for minimizing spot overlap and visualising a greater number of spots in a two-dimensional map are discussed.     

Alpha1- and alpha2-adrenoreceptor antagonist profiles of 1- and 2-[omega-(4-arylpiperazin-1-yl)alkyl]-1,2,3-benzotriazoles

A series of pharmacologically interesting 1- and 2-[omega-(4-arylpiperazin-1-yl)alkyl]-1,2,3-benzotriazoles, compounds 1-27, were synthesized (Scheme) and subjected to various biological studies to identify structure-activity relationships (SAR). The new compounds were found to exhibit good non-selective binding affinity towards the alpha1-adrenoreceptor (Table 1). In several cases, high functional antagonism was observed towards the alpha1A-, alpha1B-, and alpha1D-adrenoreceptor subtypes (Table 2). The selectivity for these three subtypes was comparable with or superior to that displayed by the standard drug prazosin. The most-common selectivity rank order was alpha1D > alpha1B > alpha1A, followed by alpha1B > alpha1D > alpha1A. In functional experiments, antagonism towards the alpha2-adrenoreceptor was generally low; however, a few compounds were endowed with significant antagonist properties (pA2 values of up to 7.87).     

Specific antitumor targetable beta-cyclodextrin-poly(ethylene glycol)-folic acid drug delivery bioconjugate

The tumor targeting properties of a new drug carrier synthesized by bioconjugation of folic acid (FA) to beta-cyclodextrins through a poly(ethylene glycol) (PEG) spacer (CD-PEG-FA) were investigated. Surface plasmon resonance demonstrated that CD-PEG-FA specifically interacts with immobilized folate binding protein (FBP) while the naked beta-cyclodextrins do not display any specific interaction. In vitro studies demonstrated that CD-PEG-FA was devoid of cell toxicity. [(3)H]-folic acid/CD-PEG-FA competition binding investigations performed with folate receptor overexpressing human epidermal carcinoma KB cells showed that CD-PEG-FA had about 14 times lower tumor cell binding capacity than free folic acid. The carrier cell trafficking properties were investigated using rhodamine-B as fluorescent probe, which possesses 3000 and 4580 M(-)(1) inclusion constants for CD-PEG-FA and beta-cyclodextrins, respectively. Cell-associated fluorescence measurements showed that CD-PEG-FA does not promote the rhodamine-B uptake into non-folate receptor expressing human lung carcinoma MCF7 cells while 19% higher accumulation in KB cells was found with respect to rhodamine-B loaded beta-cyclodextrins. Confocal laser scanning microscopy indicated the presence of cytosolic red fluorescent spots after 2 h of incubation of KB cells with rhodamine-B included CD-PEG-FA. The fluorescent dye resided primarily in small spots, namely, endosomes and multivesicular bodies. At 1 h after pulsed incubation, wider red fluorescent cellular structures appeared as a fusion of previous structures.     

Protective T cell immunity against malaria liver stage after vaccination with live sporozoites under chloroquine treatment

In this study we present the first systematic analysis of the immunity induced by normal Plasmodium yoelii sporozoites in mice. Immunization with sporozoites, which was conducted under chloroquine treatment to minimize the influence of blood stage parasites, induced a strong protection against a subsequent sporozoite and, to a lesser extent, against infected RBC challenges. The protection induced by this immunization protocol proved to be very effective. Induction of this protective immunity depended on the presence of liver stage parasites, as primaquine treatment concurrent with sporozoite immunization abrogated protection. Protection was not found to be mediated by the Abs elicited against pre-erythrocytic and blood stage parasites, as demonstrated by inhibition assays of sporozoite penetration or development in vitro and in vivo assays of sporozoite infectivity or blood stage parasite development. CD4(+) and CD8(+) T cells were, however, responsible for the protection through the induction of IFN-gamma and NO.     

Distinct footprints of TCR engagement with highly homologous ligands

T cell receptor engagement promotes proliferation, differentiation, survival, or death of T lymphocytes. The affinity/avidity of the TCR ligand and the maturational stage of the T cell are thought to be principal determinants of the outcome of TCR engagement. We demonstrate in this study that the same mouse TCR preferentially uses distinct residues of homologous peptides presented by the MHC molecules to promote specific cellular responses. The preference for distinct TCR contacts depends on neither the affinity/avidity of TCR engagement (except in the most extreme ranges), nor the maturity of engaged T cells. Thus, different portions of the TCR ligand appear capable of biasing T cells toward specific biological responses. These findings explain differences in functional versatility of TCR ligands, as well as anomalies in the relationship between affinity/avidity of the TCR for the peptide/MHC and cellular responses of T cells.