Models to assess how best to replace dengue virus vectors with Wolbachia-infected mosquito populations

Dengue fever is increasing in importance in the tropics and subtropics. Endosymbiotic Wolbachia bacteria as novel control methods can reduce the ability of virus transmission. So, many mosquitoes infected with Wolbachia are released in some countries so that strategies for population replacement can be fulfilled. However, not all of these field trails are successful, for example, releases on Tri Nguyen Island, Vietnam in 2013 failed. Thus, we evaluated a series of relevant issues such as (a) why do some releases fail? (b) What affects the success of population replacement? And (c) Whether or not augmentation can block the dengue diseases in field trials. If not, how we can success be achieved? Models with and without augmentation, incorporating the effects of cytoplasmic incompatibility (CI) and fitness effects are proposed to describe the spread of Wolbachia in mosquito populations. Stability analysis revealed that backward bifurcations and multiple attractors may exist, which indicate that initial quantities of infected and uninfected mosquitoes, augmentation methods (timing, quantity, order and frequency) may affect the success of the strategies. The results show that successful population replacement will rely on selection of suitable strains of Wolbachia and careful design of augmentation methods

Broad Surveys of DNA Viral Diversity Obtained through Viral Metagenomics of Mosquitoes

Viruses are the most abundant and diverse genetic entities on Earth; however, broad surveys of viral diversity are hindered by the lack of a universal assay for viruses and the inability to sample a sufficient number of individual hosts. This study utilized vector-enabled metagenomics (VEM) to provide a snapshot of the diversity of DNA viruses present in three mosquito samples from San Diego, California. The majority of the sequences were novel, suggesting that the viral community in mosquitoes, as well as the animal and plant hosts they feed on, is highly diverse and largely uncharacterized. Each mosquito sample contained a distinct viral community. The mosquito viromes contained sequences related to a broad range of animal, plant, insect and bacterial viruses. Animal viruses identified included anelloviruses, circoviruses, herpesviruses, poxviruses, and papillomaviruses, which mosquitoes may have obtained from vertebrate hosts during blood feeding. Notably, sequences related to human papillomaviruses were identified in one of the mosquito samples. Sequences similar to plant viruses were identified in all mosquito viromes, which were potentially acquired through feeding on plant nectar. Numerous bacteriophages and insect viruses were also detected, including a novel densovirus likely infecting Culex erythrothorax. Through sampling insect vectors, VEM enables broad survey of viral diversity and has significantly increased our knowledge of the DNA viruses present in mosquitoes

Treatment with a corticotrophin releasing factor 2 receptor agonist modulates skeletal muscle mass and force production in aged and chronically ill animals

<p>Abstract</p> <p>Background</p> <p>Muscle weakness is associated with a variety of chronic disorders such as emphysema (EMP) and congestive heart failure (CHF) as well as aging. Therapies to treat muscle weakness associated with chronic disease or aging are lacking. Corticotrophin releasing factor 2 receptor (CRF2R) agonists have been shown to maintain skeletal muscle mass and force production in a variety of acute conditions that lead to skeletal muscle wasting.</p> <p>Hypothesis</p> <p>We hypothesize that treating animals with a CRF2R agonist will maintain skeletal muscle mass and force production in animals with chronic disease and in aged animals.</p> <p>Methods</p> <p>We utilized animal models of aging, CHF and EMP to evaluate the potential of CRF2R agonist treatment to maintain skeletal muscle mass and force production in aged animals and animals with CHF and EMP.</p> <p>Results</p> <p>In aged rats, we demonstrate that treatment with a CRF2R agonist for up to 3 months results in greater extensor digitorum longus (EDL) force production, EDL mass, soleus mass and soleus force production compared to age matched untreated animals. In the hamster EMP model, we demonstrate that treatment with a CRF2R agonist for up to 5 months results in greater EDL force production in EMP hamsters when compared to vehicle treated EMP hamsters and greater EDL mass and force in normal hamsters when compared to vehicle treated normal hamsters. In the rat CHF model, we demonstrate that treatment with a CRF2R agonist for up to 3 months results in greater EDL and soleus muscle mass and force production in CHF rats and normal rats when compared to the corresponding vehicle treated animals.</p> <p>Conclusions</p> <p>These data demonstrate that the underlying physiological conditions associated with chronic diseases such as CHF and emphysema in addition to aging do not reduce the potential of CRF2R agonists to maintain skeletal muscle mass and force production.</p

Kernel lessons intermediate students book

74-151 p.; 24 cm

Kernel lessons intermediate students

73 p.; 24 cm

Bond indices, enthalpies and relative stabilities of real and hypothetical closo-BnHc−n clusters (n = 5–12; c = 0, 2 or 4) as revealed by the molecular-orbital bond index method

Bond indices (I) have been calculated, using the CNDO-based molecular-orbital bond index method, for real and hypothetical closo borane species, BnHc−n (n = 5–12; c = 0, 2 or 4), and used to infer their relative stabilities by means of the bond index (I)bond enthalpy [E (kJ mol−1)] equations E(BB) = 297.9I(BB) and E(BH) = 374.8I(BH). For the species able to tolerate n + 2 skeletal electron pairs (n = 8, 9 or 11) in closed-shell electronic configurations, estimates of the relative stabilities of alternative nido structures for the anions BnH4−n have been made. Detailed assessments of the changes in bond index with electron numbers of particular edge types for BnHc−n species (n = 8, 9 or 11; c = 0, 2 or 4) have been carried out, providing quantitative confirmation of earlier qualitative predictions, and showing that generally for the “normal” closo BnH2−n species addition or removal of an electron pair leads to the same type of polyhedral distortion, because, where the HOMO of BnH2−n is bonding for a particular edge, the LUMO is antibonding

Cluster bonding and energetics of the borane anions, BnHn2− (n = 5–12): A comparative study using bond length—bond enthal

Cluster bond enthalpies, EL(BB), and orders, n̄(BB), for the structurally characterised closo anions, BnHn2− (n = 6 and 8–12), have been estimated using the logarithmic length—enthalpy and enthalpy—order relationships EL(BB) (kJ mol−1) = 1.766 × 1011 [L(BB)]−4.0 and EL(BB) (kJ mol−1) = 318.8[n̄(BB)]0.697, respectively. In a parallel study, the molecular-orbital bond index CNDO-based calculation method has been used to give BB and BH bond indices, I(BB) and I(BH), from which bond index based bond enthalpies, EI, have been calculated using the relationships EI(BB) = 297.9 I(BB) and EI(BH) = 374.8I(BH) (enthalpies in kJ mol−1; lengths in pm). From these, total skeletal bond enthalpies Σ E(BB), and total bond enthalpies, Σ E(BB) + Σ E(BH), have been calculated. Although calculated values of EL and Σ EL generally exceed those of EI and Σ EI by some 8% and calculated values of I generally exceed those of n̄ by a greater amount, the trends in these parameters for the series of BnHn2− anions are very similar, showing the greater efficiency with which the n + 1 skeletal electron pairs are used as n increases. However, the two approaches differ in that, whereas the Σ EI values suggest that the anions are all of comparable stability, the ΣEL values clearly show B6H62−, B10H102− and B12H122− to be more stable than B8H82−, B9H92− and B11H112−. The interatomic distances in B7H72− and in the unknown B5 H52− are estimated and used to assess their relative stabilities. The EL values suggest that B7 H72− is of comparable stability to B8H82− etc., but show B5H52− as relatively unstable. The EI values suggest that both of these anions should be relatively stable members of the series of closo anions