Vector Competence of American Mosquitoes for Three Strains of Zika Virus

In 2015, Zika virus (ZIKV; Flaviviridae; Flavivirus) emerged in the Americas, causing millions of infections in dozens of countries. The rapid spread of the virus and the association with disease outcomes such as Guillain-Barré syndrome and microcephaly make understanding transmission dynamics essential. Currently, there are no reports of vector competence (VC) of American mosquitoes for ZIKV isolates from the Americas. Further, it is not clear whether ZIKV strains from other genetic lineages can be transmitted by American Aedes aegypti populations, and whether the scope of the current epidemic is in part facilitated by viral factors such as enhanced replicative fitness or increased vector competence. Therefore, we characterized replication of three ZIKV strains, one from each of the three phylogenetic clades in several cell lines and assessed their abilities to be transmitted by Ae. aegypti mosquitoes. Additionally, laboratory colonies of different Culex spp. were infected with an American outbreak strain of ZIKV to assess VC. Replication rates were variable and depended on virus strain, cell line and MOI. African strains used in this study outcompeted the American strain in vitro in both mammalian and mosquito cell culture. West and East African strains of ZIKV tested here were more efficiently transmitted by Ae. aegypti from Mexico than was the currently circulating American strain of the Asian lineage. Long-established laboratory colonies of Culex mosquitoes were not efficient ZIKV vectors. These data demonstrate the capacity for additional ZIKV strains to infect and replicate in American Aedes mosquitoes and suggest that neither enhanced virus replicative fitness nor virus adaptation to local vector mosquitoes seems likely to explain the extent and intensity of ZIKV transmission in the Americas.     

Geometric and traditional morphometrics for the assessment of character state identity: multivariate statistical analyses of character variation in the genus Arrenurus (Acari,Hydrachnidia, Arrenuridae)

Geometric and traditional morphometric approaches are tested to describe and reveal taxonomic characters and character states in variation of shape and size of idiosoma morphology in the Arrenuridae. Patterns of variation of idiosoma and glandularia features of males from 11 Mexican species of Arrenurus (Megaluracarus) and two species of subgenus Dadayella were explored with five landmark configurations and three sets of interlandmark distances. Separate principal component analyses (PCA) and canonical variate analyses (CVA) were performed for each data set. The eight multivariate analyses of variance among 13 a priori groups (species) detected significantly different morphometric variants, which were interpreted as different taxonomic character states. Patterns of character state similarity among species were examined with unweighted‐pair grouping method using averages (UPGMA) cluster analyses on Mahalanobis distances. Analyses of five landmark configurations revealed important taxonomical variation in the anterior idiosoma outline (10 character states), the outline of the posterior region or cauda (13 states), the distribution of postocularia, and the second and third pairs of dorsoglandularia (nine states), the fourth pair of dorsoglandularia (three states), and ventroglandularia on the posterior side of idiosoma (nine character states). Multivariate analyses of three sets of distance measurements also resulted in the detection of potential taxonomic characters related to idiosoma size (12 character states), postocularia and dorsoglandularia (13 states), and ventroglandularia (nine character states). Morphometric analyses of distances and shapes provide a formal basis for the interpretation of taxonomic characters, and for the discovery of character states. These characters should be investigated further in a wider sample of species for the phylogenetic systematics of these water mites. In the meantime, idiosoma regions and structures were tested for congruence in a phylogenetic analysis, and were proposed as homologous among the species sampled.     

A global review and meta-analysis of applications of the freshwater Fish Invasiveness Screening Kit

Reviews in Fish Biology and Fisheries - The freshwater Fish Invasiveness Screening Kit (FISK) has been applied in 35 risk assessment areas in 45 countries across the six inhabited continents (11...     

Nematode ascaroside enhances resistance in a broad spectrum of plant–pathogen systems

Recognition of specific molecule signatures of microbes, including pathogens, induces innate immune responses in plants, as well as in animals. Analogously, a nematode pheromone, the ascaroside ascr#18, induces hallmark plant defences including activation of (a) mitogen‐activated protein kinases, (b) salicylic acid‐ and jasmonic acid‐mediated defence signalling pathways and (c) defence gene expression and provides protection to a broad spectrum of pathogens. Ascr#18 is a member of an evolutionarily conserved family of nematode signalling molecules and is the major ascaroside secreted by plant–parasitic nematodes. Here, we report the effects of ascr#18 on resistance in four of the major economically important crops: maize, rice, wheat and soybean to some of their associated pathogens. Treatment with low nanomolar to low micromolar concentrations of ascr#18 provided from partial to strong protection in seven of eight plant–pathogen systems tested with viruses, bacteria, fungi, oomycetes and nematodes. This research may have potential to improve agricultural sustainability by reducing use of potentially harmful agrochemicals and enhance food security worldwide.     

Gustatory thresholds for food-associated sugars in the spider monkey (Ateles geoffroyi)

The purpose of this study was to determine gustatory thresholds for five different food-associated sugars in Ateles geoffroyi. Using a two-bottle test, three adult spider monkeys were found to significantly prefer concentrations as low as 3 mM sucrose, 15 mM fructose, 20 mM glucose, and 10 mM lactose over tap water. Maltose was significantly discriminated down to 20 mM with individual animals showing either a preference or an aversion, or an inverted U-shaped function of preference toward higher concentrations of this carbohydrate. The results showed the spider monkey to respond to lower sugar concentrations compared to other nonhuman primates tested so far and thus support the assumptions that Ateles geoffroyi may use sweetness as a criterion for food selection, and that the remarkably high sweet-taste sensitivity of this frugivorous species might be correlated with its dietary specialization. © 1996 Wiley-Liss, Inc.     

Focus: The Science of Stress: PTSD Among Shidu Parents in China: The Roles of Personality Types and Social Support

Background: The psychological problems of Shidu Parents (SDP) under the China’s One-Child Policy have been documented. The purpose of this study was to investigate the relationships among personality types, social support, and post-traumatic stress disorder (PTSD) in SDP. Methods: The PTSD Checklist-Civilian Version (PCL-C), The Big Five Personality Traits (NEO), and Social Support Revalued Scale (SSRS) were administered to the sample of 149 SDP who were over 50 years old and had lost their only child more than one year ago. Results: Among SDP, mothers were more likely to develop PTSD than fathers (χ² = 11.16, p < 0.01). Parents who were extraverted had a lower risk of developing PTSD-related symptoms (χ² = 8.58, p < 0.01), and the effect of neuroticism was significant (χ² = 23.73, p < 0.01). The more social support parents utilized, the lower the incidence of PTSD (t = 4.56, p < 0.01). The result of multilevel linear regression showed that sex, neuroticism, and objective social support remained significantly different after combining all personality types and social support systems in the same model. Social support partially mediated the relationship between neuroticism and PTSD. Meanwhile, it was a complete mediator between extraversion and PTSD. Conclusions: Female sex/gender, neuroticism, and introversion were risk factors of developing PTSD, while receiving social support protected SDP from developing PTSD symptoms. Losing an only child is undoubtedly an enormous disaster for the family, which has become a huge, unavoidable social problem that must be addressed in China.     

Human endonuclease III acts preferentially on DNA damage opposite guanine residues in DNA

The human endonuclease III homologue (hNTH1) removes premutagenic cytosine damage from DNA. This includes 5-hydroxycytosine, which has increased potential for pairing with adenine, resulting in C --> T transition mutations. Here we report that hNTH1 acts on both 5-hydroxycytosine and abasic sites preferentially when these are situated opposite guanines in DNA. Discrimination against other opposite bases is strongly dependent on the presence of magnesium. To further elucidate this effect, we have introduced mutations in the helix-hairpin-helix domain of hNTH1 (K212S, P211R, +G212, and DeltaP211), and measured the kinetics of 5-hydroxycytosine removal of the mutants relative to wild type. The K212S and DeltaP211 (truncated hairpin) mutant proteins were both inactive, whereas the extended hairpin in the +G212 mutant diminished recognition and binding to 5-hydroxycytosine-containing DNA. The P211R mutant resembled native hNTH1, except for decreased specificity of binding. Despite the altered kinetic parameters, the active mutants retained the ability to discriminate against the pairing base, indicating that enzyme interactions with the opposite strand relies on other domains than the active site helix-hairpin-helix motif.