Evaluation of the Larvicidal Efficacy of Five Indigenous Weeds against an Indian Strain of Dengue Vector, Aedes aegypti

Background and Objectives. Aedes aegypti, dengue fever mosquito, is primarily associated with the transmission of dengue and chikungunya in tropical and subtropical regions of the world. The present investigations were carried out to assess the larvicidal efficiency of five indigenous weeds against Ae. aegypti. Methods. The 1,000 ppm hexane and ethanol extracts prepared from the leaves and stem of five plants (Achyranthes aspera, Cassia occidentalis, Catharanthus roseus, Lantana camara, and Xanthium strumarium) were screened for their larvicidal activity against early fourth instars of dengue vector. The extracts which could cause 80–100% mortality were further investigated for their efficacy. Results. The preliminary screening established the efficacy of hexane extracts as compared to the ethanol extracts. Further investigations revealed the highest larvicidal potential of A. aspera extracts exhibiting LC50 value of 82.555 ppm and 68.133 ppm, respectively. Further, their leaf extracts showed 5–85.9% higher larvicidal activity and stem extracts exhibited 0.23- to 0.85-fold more efficiency than the other four extracts. Conclusion. The present investigations suggest the possible use of A. aspera as an ideal ecofriendly, larvicidal agent for the control of dengue vector, Ae. aegypti. Future studies are, however, required to explore and identify the bioactive component involved and its mode of action

Molecular Epidemiology and Sequence Analysis of Rabies Virus Isolates from North and North East India

In the present study phylogenetic analysis of 30 rabies virus (RV) isolates collected from North and North East India between 2013 and 2016 was carried out. Analysis of two sets of sequence of non-coding G-L intergenic region, based upon a 132-nucleotide region of the cytoplasmic domain (CD) of the G gene (G-CD) and a 549-nucleotide (Psi-L) was done. The phylogenetic tree constructed using 549 nucleotide sequence of hyper variable region (Psi-L) showed the same topology as that obtained on the basis of 132 nucleotide sequence of G-CD region. Four different genetic clusters (GCs) distributed among three geographical regions were identified. Comparison of deduced amino acid (aa) sequences showed four amino acid changes - aa462G, aa465H/R and aa468K in G-CD region. The change observed at position aa465R indicated the spillover of Indian wild strain (mongoose) to domestic animals in Delhi region. The homology among the Indian RV isolates shared >97% nucleotide similarity irrespective of their geographical regions and hosts. The study revealed that the RV isolates are region specific, not host specific and all belonged to genotype 1

A facile and rapid method for green synthesis of Achyranthes aspera stem extract-mediated silver nano-composites with cidal potential against Aedes aegypti L.

Aedes aegypti L. is the primary vector associated with transmission of globally concerned diseases; Zika, yellow fever, dengue and Chikungunya. Present study investigates an efficient, alternative and comparative approach for mosquito control which is safe to environment and non-target organisms. The silver nano-composites (AgNCs) were synthesized from the aqueous stem extract of Achyranthes aspera (AASE) using different concentration of aqueous silver nitrate (AgNO3). The synthesis was tracked by UV-vis spectrophotometer and particle size analyser (DLS). The evaluation of their larvicidal potential against early fourth instars of Ae. aegypti showed significant potency, the toxicity increasing with the concentration of silver nitrate. The 24, 48 and 72 h bioassays resulted in respective LC50 values of 26.693, 1.113 and 0.610 μg/mL (3 mM AASE-AgNO3) 9.119, 0.420 and 0.407 μg/mL (4 mM AASE-AgNO3) and that of 4.283, 0.3 and 0.248 μg/mL (5 mM AASE-AgNO3). Keeping in view the significantly high larvicidal efficiency at lower concentration of silver nitrate, the 4 mM nano-composites were selected over 5 mM composites for further biophysical characterization carried out by X-ray Diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Scanning electron microscopy (SEM), Energy dispersive X-ray (EDX) spectroscopy and Transmission electron microscopy (TEM). SEM and TEM confirmed the synthesis of spherical poly-dispersed AgNCs with average size ranging from 1–30 nm. Characterization through XRD showed the crystalline face-centered-cubic (fcc) structure of AgNCs with the highest intense peak obtained at 2θ value of 31.82°. FT-IR data suggests complex nature of AgNCs showing clearly defined peaks in different ranges. The present investigations recommend AgNCs of A. aspera stems as a low-cost and eco-friendly alternative to chemical insecticides for mosquito control. Keywords: Silver nano-composites, Achyranthes aspera, Aedes aegypti, SEM, TEM, EDX, XRD, FT-I

Electrospun polyacrylonitrile nanofibrous membranes for chitosanase immobilization and its application in selective production of chitooligosaccharides

Polyacrylonitrile nanofibrous membranes (PANNFM) were prepared by electrospinning from 10 wt.% of PAN solution and its surface was modified by amidination reaction. A new chitosan degrading enzyme from Aspergillus sp. was covalently immobilized on PANNFM. Immobilization efficiency of 80% was achieved by activating PANNFM surface for 30 min followed by 2 h treatment with enzyme solution. The optimum temperature and pH for immobilized enzyme were 50 degrees C and 5.8, respectively. The immobilized chitosanase retained >70% activity after ten repeated batch reaction and could be stored up to 60 days at 4 degrees C with minor loss in activity. Chitosan hydrolysis using different substrates were studied using immobilized chitosanase in batch conditions. Continuous selective production of chitooligosaccharides (dimer to hexamer) by changing the temperature was achieved by PANNFM-chitosanase

Diversity and Abundance of Butterfly Species Complex in Two Diverse Habitats of Jawaharlal Nehru Krishi Vishwavidyalaya, India

Butterflies are important bio-indicators that should be protected to conserve the biodiversity and environment. They play an important role in the food chain and are valuable pollinators in the local environment. The present study investigated and compared the butterfly abundance and diversity within two different habitats (i) Undisturbed and (ii) Disturbed, in Jawaharlal Nehru Krishi Vishwavidyalaya Campus, Jabalpur Madhya Pradesh. A total of 24 butterfly species were recorded during the study from June 2022 to July 2023 using transects with the aid of sweep nets. An overall total of 2537 butterflies were recorded, which spread across 05 families 17 genera and 23 species. The most abundant family of butterflies caught in undisturbed ecosystems was Pieridae 38% followed by Nymphalidae 27%, Lycaenidae 14%, Papilionidae and Hesperiidae 7%. In disturbed ecosystems butterflies were distributed as Pieridae being dominated with 52% followed by Lycaenidae at 22%, Nymphalidae at 16%, Hesperiidae at 7% and Papilionidae at 3%. The undisturbed habitat was more diversified (H’-1.59) in butterfly diversity than the disturbed habitat (H’- 1.20)