Evaluation of Insecticides Susceptibility and Malaria Vector Potential of Anopheles annularis s.l. and Anopheles vagus in Assam,India

During the recent past, development of DDT resistance and reduction to pyrethroid susceptibility among the malaria vectors has posed a serious challenge in many Southeast Asian countries including India. Current study presents the insecticide susceptibility and knock-down data of field collected Anopheles annularis sensu lato and An. vagus mosquito species from endemic areas of Assam in northeast India. Anopheles annularis s.l. and An. vagus adult females were collected from four randomly selected sentinel sites in Orang primary health centre (OPHC) and Balipara primary health centre (BPHC) areas, and used for testing susceptibility to DDT, malathion, deltamethrin and lambda-cyhalothrin. After insecticide susceptibility tests, mosquitoes were subjected to VectorTest^™ assay kits to detect the presence of malaria sporozoite in the mosquitoes. An. annularis s.l. was completely susceptible to deltamethrin, lambda-cyhalothrin and malathion in both the study areas. An. vagus was highly susceptible to deltamethrin in both the areas, but exhibited reduced susceptibility to lambda-cyhalothrin in BPHC. Both the species were resistant to DDT and showed very high KDT₅₀ and KDT₉₉ values for DDT. Probit model used to calculate the KDT₅₀ and KDT₉₉ values did not display normal distribution of percent knock-down with time for malathion in both the mosquito species in OPHC (p<0.05) and An. vagus in BPHC (χ² = 25.3; p = 0.0), and also for deltamethrin to An. vagus in BPHC area (χ² = 15.4; p = 0.004). Minimum infection rate (MIR) of Plasmodium sporozoite for An. vagus was 0.56 in OPHC and 0.13 in BPHC, while for An. annularis MIR was found to be 0.22 in OPHC. Resistance management strategies should be identified to delay the expansion of resistance. Testing of field caught Anopheles vectors from different endemic areas for the presence of malaria sporozoite may be useful to ensure their role in malaria transmission.     

Characterization of alpha-synuclein interactions with selected aggregation-inhibiting small molecules

The 140-residue protein alpha-synuclein (aS) has been implicated in the molecular chain of events leading to Parkinson's disease, which relates to the hierarchical aggregation of aS into soluble oligomers and insoluble fibrils. A number of small organic molecules have been reported to inhibit aS aggregation. Here, the interactions of chlorazole black E, Congo red, lacmoid, PcTS-Cu (2+), and rosmarinic acid with aS are examined by NMR spectroscopy to identify aS sequence elements that are masked by these compounds. Surprisingly, similar aS interaction sites, encompassing residues 3-18 and 38-51, were obtained for all molecules at equimolar small molecule:aS ratios. At higher ratios, virtually the entire amphiphilic region of aS (residues 2-92) is affected, revealing the presence of additional, lower affinity interaction sites. Upon rearranging the high-affinity interaction sites over the aS amphiphilic region in an aS mutant form, perturbations of the entire amphiphilic region were found to have already been obtained at equimolar ratios, indicating a high specificity for the original binding sites. CD spectroscopy reveals that, in the presence of the small molecules, the aS structure is still dominated by random-coil characteristics. The strongest effects are exerted by molecules that contain sulfonate groups adjacent to aromatic systems, often present in multiple copies in a symmetrical arrangement, suggesting that these elements are useful for developing an aS-specific chemical chaperone.     

Spectrophotometric ferric ion biosensor from Pseudomonas fluorescens culture

Pseudomonas fluorescens cultures produce fluorescent siderophores. By utilizing optimal conditions for maximizing siderophore production in shake flask cultures of P. fluorescens, we report successful characterization of the culture broth supernatant as a robust ferric ions biosensor. For characterizing the ferric ions biosensor, we tested the effects of pH, buffers, different ferric salts and possible interference by ferrous ions under different solution conditions. We find that the biosensor is very specific to ferric ions only with sensitivity to concentrations as low as 10 microM. Further, the response time of the biosensor is the shortest (approximately 5 min or smaller) for citrate as the accompanying anion with ferric ions. While the response time is longer than that expected of normal biosensors, it is well compensated by the simplicity and economics of the biosensor production. Extremely low standard deviations in several experimental repeats also highlight the robustness of the ferric ions biosensor. Most importantly, the biosensor is extremely easy to use due to its straightforward spectrophotometric applications. We also show the utility of the biosensor with the high resolution technique of fluorescence microscopy. Finally, we report a novel mechanistic finding that siderophores present in the culture broth supernatants have two distinct optically active sites on them, which can be monitored independently in presence or absence of ferric ions.     

Systematic Development of Transethosomal Gel System of Piroxicam: Formulation Optimization, <Emphasis Type="Italic">In Vitro</Emphasis> Evaluation,and <Emphasis Type="Italic">Ex Vivo</Emphasis> Assessment

Piroxicam is used in the treatment of rheumatoid arthritis, osteoarthritis, and other inflammatory diseases. Upon oral administration, it is reported to cause ulcerative colitis, gastrointestinal irritation, edema and peptic ulcer. Hence, an alternative delivery system has been designed in the form of transethosome. The present study describes the preparation, optimization, characterization, and ex vivo study of piroxicam-loaded transethosomal gel using the central composite design. On the basis of the prescreening study, the concentration of lipids and ethanol was kept in the range of 2–4% w/v and 0–40% v/v, respectively. Formulation was optimized by measuring drug retention in the skin, drug permeation, entrapment efficiency, and vesicle size. Optimized formulation was incorporated in hydrogel and compared with other analogous vesicular (liposomes, ethosomes, and transfersomes) gels for the aforementioned responses. Among the various lipids used, soya phosphatidylcholine (SPL 70) and ethanol in various percentages were found to affect drug retention in the skin, drug permeation, vesicle size, and entrapment efficiency. The optimized batch of transethosome has shown 392.730 μg cm^?2 drug retention in the skin, 44.312 μg cm^?2 h^?1 drug permeation, 68.434% entrapment efficiency, and 655.369 nm vesicle size, respectively. It was observed that the developed transethosomes were found superior in all the responses as compared to other vesicular formulations with improved stability and highest elasticity. Similar observations were noted with its gel formulation.     

Salt Marsh Restoration in Connecticut: 20 Years of Science and Management

In 1980 the State of Connecticut began a tidal marsh restoration program targeting systems degraded by tidal restrictions and impoundments. Such marshes become dominated by common reed grass (Phragmites australis) and cattail (Typha angustifolia and T. latifolia), with little ecological connection to Long Island Sound. The management and scientific hypothesis was that returning tidal action, reconnecting marshes to Long Island Sound, would set these systems on a recovery trajectory. Specific restoration targets (i.e., pre‐disturbance conditions or particular reference marshes) were considered unrealistic. However, it was expected that with time restored tides would return ecological functions and attributes characteristic of fully functioning tidal salt marshes. Here we report results of this program at nine separate sites within six marsh systems along 110 km of Long Island Sound shoreline, with restoration times of 5 to 21 years. Biotic parameters assessed include vegetation, macroinvertebrates, and use by fish and birds. Abiotic factors studied were soil salinity, elevation and tidal flooding, and soil water table depth. Sites fell into two categories of vegetation recovery: slow, ca. 0.5%, or fast, more than 5% of total area per year. Although total cover and frequency of salt marsh angiosperms was positively related to soil salinity, and reed grass stand parameters negatively so, fast versus slow recovery rates could not be attributed to salinity. Instead, rates appear to reflect differences in tidal flooding. Rapid recovery was characterized by lower elevations, greater hydroperiods, and higher soil water tables. Recovery of other biotic attributes and functions does not necessarily parallel those for vegetation. At the longest studied system (rapid vegetation recovery) the high marsh snail Melampus bidentatus took two decades to reach densities comparable with a nearby reference marsh, whereas the amphipod Orchestia grillus was well established on a slow‐recovery marsh, reed grass dominated after 9 years. Typical fish species assemblages were found in restoration site creeks and ditches within 5 years. Gut contents of fish in ditches and on the high marsh suggest that use of restored marsh as foraging areas may require up to 15 years to reach equivalence with reference sites. Bird species that specialize in salt marshes require appropriate vegetation; on the oldest restoration site, breeding populations comparable with reference marshland had become established after 15 years. Use of restoration sites by birds considered marsh generalists was initially high and was still nearly twice that of reference areas even after 20 years. Herons, egrets, and migratory shorebirds used restoration areas extensively. These results support our prediction that returning tides will set degraded marshes on trajectories that can bring essentially full restoration of ecological functions. This can occur within two decades, although reduced tidal action can delay restoration of some functions. With this success, Connecticut's Department of Environmental Protection established a dedicated Wetland Restoration Unit. As of 1999 tides have been restored at 57 separate sites along the Connecticut coast.     

Photophysics of nanographenes: from polycyclic aromatic hydrocarbons to graphene nanoribbons

Photosynthesis Research - Graphene quantum dots (GQDs) and nanoribbons (GNRs) are classes of nanographene molecules that exhibit highly tunable photophysical properties. There have been great...     

From dispersal constraints to landscape connectivity: lessons from species distribution modeling

Connectivity plays a crucial role in determining the spread, viability, and persistence of populations across space. Dispersal across landscapes, or the movement of individuals or genes among resource patches, is critical for functional connectivity. Yet current connectivity modelling typically uses information on species location or habitat preference rather than movement, which unfortunately may not capture key dispersal limitations. We argue that recent developments in species distribution modelling provide insightful lessons for addressing this gap and advancing our understanding of connectivity. We suggest shifting the focus of connectivity modelling from locating where animals potentially disperse to a process‐based approach directed towards understanding and mapping factors that limit successful dispersal. To do so, we propose defining species dispersal requirements through identifying spatial, environmental and intrinsic constraints to successful dispersal, analogous to identifying environmental dimensions that define niches. We discuss the benefits of this constraint‐based framework for understanding the distribution of species, predicting species responses to climate change, and connectivity conservation practice. We illustrate how the framework can aid in identifying potential detrimental effects of human activities on connectivity and species persistence, and can spur the implementation of innovative conservation strategies. The proposed framework clarifies the validity and contextual utility of objectives and measures in existing connectivity models, and identifies gaps that may impede our understanding of connectivity and its integration into successful conservation strategies. We expect that this framework will facilitate a mechanistic approach to understanding and conserving connectivity, which will aid in effectively predicting and mitigating effects of ongoing environmental change.     

Rapid Diagnostic Tests for Dengue Virus Infection in Febrile Cambodian Children: Diagnostic Accuracy and Incorporation into Diagnostic Algorithms

BackgroundDengue virus (DENV) infection is prevalent across tropical regions and may cause severe disease. Early diagnosis may improve supportive care. We prospectively assessed the Standard Diagnostics (Korea) BIOLINE Dengue Duo DENV rapid diagnostic test (RDT) to NS1 antigen and anti-DENV IgM (NS1 and IgM) in children in Cambodia, with the aim of improving the diagnosis of DENV infection.ConclusionsThe DENV RDT had low sensitivity for the diagnosis of DENV infection. The high co-prevalence of infections in our cohort indicates the need for a broad microbiological assessment of non-localised febrile illness in these children.