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Scorpions of the genus Heterometrus Ehrenberg, 1828, are distributed from India and Sri Lanka throughout the Southeast Asian mainland and archipelagos as far as Wallace's Line. Despite this widespread distribution, Heterometrus was not recorded from Pakistan until a single specimen from Azad Kashmir was reported from the collection of the Pakistan Museum of Natural History, Islamabad. Perhaps because the specimen was misidentified as Heterometrus wroughtoni (Pocock, 1899), a species that occurs much farther to the southeast in India, the presence of Heterometrus in Pakistan remained uncertain until fresh material of a distinctive species of Heterometrus was recently collected at several locations in Khyber Pakhtoon Khawa. After comparison of the material with the holotype and only known specimen of a little-known species, Heterometrus latimanus (Pocock, 1894), with an indefinite type locality in "India," the Pakistani material was determined to be conspecific. In the present contribution, H. latimanus

Nanoparticles (NPs) are being recognized as antibacterial agents due to their rapidly increasing multidrug resistance in bacterial pathogens. Hence, there is an unmet need to identify the natural antibacterial agent. The present study aimed to evaluate the antibacterial activity of sericin-conjugated silver NPs synthesized by using sericin as a reducing and capping agent. Synthesized NPs were characterized by scanning electron microscope, nanolaser particle size analyzer (BT-90), Fouriertransform infrared analysis, and energy-dispersive X-ray. The biogenic NPs significantly inhibited the growth of Escherichia coli (12-15 mm zone of inhibition), Staphylococcus aureus (14.6-15.4 mm zone of inhibition), and Klebsiella pneumoniae (12.5-18 mm zone of inhibition). The stability of naturally synthesized NPs was examined at various temperatures (i.e., 4°C, 37°C, and 55°C) and pH (i.e., 3, 7, and 11). Temperature variability did not significantly affect the efficacy of NPs. However, NPs performed better at higher pH levels. This study suggested that the sericinbased silver NPs are not only effective against bacteria, but they also maintain the stability at different ranges of temperature and pH. We concluded that the sericinconjugated silver NPs possess the remarkable antibacterial potential, which suggests their large-scale use as a cheap and stable antimicrobial agent in the future. K E Y W O R D Santibacterial activity, nanoparticles, sericin, silver

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Now a day’s multidrug resistance phenomenon has become the main cause for concern and there has been an inadequate achievement in the development of novel antibiotics to treat the bacterial infections. Therefore, there is an unmet need to search for novel adjuvant. Vitamin C is one such promising adjuvant. The present study was aimed to elucidate the antibacterial effect of vitamin C at various temperatures (4°C, 37°C and 50°C) and pH (3, 8, and 11), against Gram-positive and Gram-negative bacteria at various concentrations (5-20 mg/ml) through agar well diffusion method. Growth inhibition of all bacterial strains by vitamin C was concentration-dependent. Vitamin C significantly inhibited the growth of Gram-positive bacteria: Bacillus licheniformis (25.3 ± 0.9 mm), Staphylococcus aureus (22.0 ± 0.6 mm), Bacillus subtilis (19.3 ± 0.3 mm) and Gram-negative bacteria: Proteus mirabilis (27.67 ± 0.882 mm), Klebsiella pneumoniae (21.33±0.9 mm), Pseudomonas aeruginosa (18.0 ± 1.5 mm) and Escherichia coli (18.3 ± 0.3 mm). The stability of vitamin C was observed at various pH values and various temperatures. Vitamin C showed significant antibacterial activity at acidic pH against all bacterial strains. Vitamin C remained the stable at different temperatures. It was concluded that vitamin C is an effective and safe antibacterial agent that can be used in the future as an adjunct treatment option to combat infections in humans.

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