Biology subjects

Dang, S.

Publications and source records attributed to Dang, S..

22 records · Page 2Linked to original sources

bioRxiv2020

Sugar feeding patterns of New York Aedes albopictus mosquitoes are affected by environmental dryness, flowers, and host seeking

BackgroundSugar feeding is an important behavior which may determine vector potential of mosquitoes. Sugar meals can reduce blood feeding frequency, enhance survival, and decrease fecundity, as well as provide energetic reserves to fuel energy intensive behaviors such as mating and host seeking. Sugar feeding behavior also can be harnessed for vector control (e.g. attractive toxic sugar baits). Few studies have addressed sugar feeding of Aedes albopictus, a vector of arboviruses of public health importance, including dengue and Zika viruses. To address this knowledge gap, we assessed sugar feeding patterns of Ae. albopictus for the first time in its invasive northeastern USA range. Methodology/ Principal FindingsUsing the cold anthrone fructose assay with robust sample sizes, we demonstrated that a large percentage of both male (49.6%) and female (41.8%) Ae. albopictus fed on plant or homopteran derived sugar sources within 24 hrs of capture. Our results suggest that sugar feeding behavior increases when environmental conditions are dry and may vary by behavioral status (host seeking vs. resting). Furthermore, mosquitoes collected on properties with flowers (>3 blooms) had higher fructose concentrations compared to those collected from properties with few to no flowers (0-3). Conclusions/SignificanceOur results provide the first evidence of Ae. albopictus sugar feeding behavior in the Northeastern US and reveal relatively high rates of sugar feeding. These results suggest the potential success for regional deployment of toxic sugar baits. In addition, we demonstrate the impact of several environmental and mosquito parameters (environmental dryness, presence of flowers, host seeking status, and sex) on sugar feeding. Placing sugar feeding behavior in the context of these environmental and mosquito parameters provides further insight into spatiotemporal dynamics of feeding behavior for Ae. albopictus, and in turn, provides information for evidence-based control decisions.

ecology↗

bioRxiv2019

Dynamics of Auxilin1 and GAK in clathrin-1 mediated traffic

Clathrin coated vesicles formed at the plasma membrane lose their clathrin lattice within seconds of pinching off, through the action of the Hsc70 \"uncoating ATPase\". The J-domain containing proteins, auxilin1 (Aux1) and auxilin2/cyclin-G dependent kinase (GAK), recruit Hsc70. Aux1 and GAK are closely related homologs, each with a phosphatase- and tensin-like (PTEN-like) domain, a clathrin-binding region, and a C-terminal J-domain; GAK has an additional, N-terminal Ser/Thr kinase domain. The PTEN-like domain has no phosphatase activity, but it can recognize phosphatidylinositol phosphate head groups. Aux1 and GAK appear on coated vesicles in successive transient bursts, immediately after dynamin mediated membrane scission has released the vesicle from the plasma membrane. We show here that these bursts represent recruitment of a very small number of auxilins such that even 4-6 molecules are sufficient to mediate uncoating. In contrast, we could not detect auxilins in abortive pits or at any time during coated-pit assembly. We have also shown previously that clathrin coated vesicles have a dynamic phosphoinositide landscape, and we have proposed that lipid head group recognition might determine the timing of Aux1 and GAK appearance. We now show that differential recruitment of Aux1 and GAK correlates with temporal variations in phosphoinositide composition, consistent with a lipid-switch timing mechanism.

cell biology↗

bioRxiv2019

Critical Variables to be Considered when Attempting to Estimate Blood Ethanol Concentrations in Rats from g/kg Exposure Data

BackgroundIn rodent studies of ethanol (EtOH) consumption where blood sample collection does not occur, there is often mention of likely BECs based on prior studies. These studies may vary in dose(s) used, age/sex/species, or administration route. Often, intake studies may presume that binge-levels were achieved without knowing that BECs exceeded 80 mg% (binge threshold). In human studies, estimated BECs (eBECs) have been derived using complex formulas that consider EtOH consumption level and the weight and sex of the individual.\n\nMethodThree datasets were used to derive eBECs using a conversion factor (CF) that considers gram (g) of EtOH per kilogram (kg) of animal weight and other variables that may influence BECs such as age, sex, dose, route, vehicle, chronicity, and timing post-exposure. Regression analyses were also conducted for each dataset, building regression models with BEC as the response and other variables in the study specific to each dataset as predictor variables.\n\nResultsDataset1 assessed age, sex and post-injection time point. Both CF and regression analyses determined that different CFs should be used for 10- and 30-min post-administration time points. Dataset2 assessed age, dose, vehicle and post-intubation time point. Depending on the post-intubation time point, several CFs were used to derive eBECs. When weight was not used as a regression variable, data across approaches corresponded, with age differences emerging later in elimination phase. In Dataset3 that used BECs from a repeated intake study, chronic exposure influenced CFs, although regression analysis did not yield similar findings.\n\nConclusionsAlthough eBECs can be derived, critical variables vary with subject and test conditions and do not always concur with results of regression analyses. Although, not designed to replace assessment of BECs when sample collection is possible, the CF approach may prove useful when estimating BECs in studies where assessments are not feasible.

neuroscience↗

bioRxiv2018

Structural insight into TRPV5 channel function and modulation

TRPV5 (transient receptor potential vanilloid) is a unique calcium-selective TRP channel that is essential for calcium homeostasis. TRPV5 and its close homologue TRPV6 do not exhibit thermosensitivity or ligand-dependent activation, unlike other TRPV channels, but are constitutively opened at physiological membrane potentials. Here, we report high resolution electron cryo-microscopy (cryo-EM) structures of truncated and full length TRPV5 in lipid nanodisc, as well as a TRPV5 W583A mutant structure and a complex structure of TRPV5 with calmodulin (CaM). These structures highlight and explain functional differences between the thermosensitive and calcium-selective TRPV channels. An extended S1-S2 linker folds on top of the channel that might shield it from modulation by extracellular factors. Resident lipid densities in the homologous vanilloid pocket are different from those previously found in TRPV1, supporting a comparatively more rigid architecture of TRPV5. A ring of tryptophan residues (W583) at the bottom of the pore coordinates a density and mutation of W583 resultes in opening of the lower gate. Moreover, we provide structural insight into the calcium-dependent channel inactivation and propose a flexible stoichiometry for TRPV5 and CaM binding.

biophysics↗