Sawlang Borsingh Wann

Toxicological effects of arsenic exposure in a freshwater teleost fish, Channa punctatus

High concentration of arsenic in groundwater in the north-eastern states of India has become a major cause of concern. Inorganic arsenic of geological origin is found in groundwater used as drinking-water in several parts of the world. Arsenic is used in various industries and agriculture and excessive arsenic finds its way into lakes and rivers. Since arsenic is a known human carcinogen, the epidemiological studies are extremely important for this metal. Fish are ideal organisms to work with in toxicogenomics studies due to the strong power of fish models to establish biomarkers of exposure. Since, fishes respond to toxicants in a similar way as higher vertebrates, they can be used to screen for chemicals that are potentially teratogenic and carcinogenic to humans. Also fish absorbs dissolved or available metals and therefore can serve as indicator of metal pollution. The objectives of this work were to examine the toxicological effect and molecular changes caused by a heavy metal sodium arsenite (NaAsO 2 ), in Channa punctatus. When fishes were exposed to NaAsO 2 , it induced death of the fishes in a concentration-dependent manner. 100 ppm, the highest concentration tested in this study, was found to be the deadliest and it induced death of the fishes within 18 to 20 h. As the concentration lowered the survival time increased dose dependently. Liver is the target organ of arsenic toxicity. Fish liver plays an important role in uptake, accumulation, bio-transformation and excretion of arsenic. We investigated the effect of NaAsO 2 on fish liver. NaAsO 2 was found to cause liver chromosomal DNA fragmentation and expression of certain proteins. Key words: DNA Fragmentation, sodium arsenite, Channa punctatus.

Evaluation of in-vitro antifungal activity of medicinal plants against phytopathogenic fungi

Fourteen medicinal plants belonging to 13 families were collected and extracted with petroleum ether (PE), chloroform, methanol and water to yield 60 crude extracts. Using agar diffusion method, these extracts were evaluated for antifungal activity on the growth of five phytopathogenic fungi. Among all the extracts tested, PE, chloroform and methanol extracts of Piper betle L. and PE and chloroform extracts of Allamanda cathartica exhibited promising antifungal activity. Minimum inhibitory concentration (MIC) values of the above promising extracts were determined using broth dilution technique and observed that chloroform extract of P. betle L. exhibited the least MIC value ranging from 280 to 1130 μg ml−1. In this study, we report chloroform extract of P. betle L. to be thermally stable even when steam sterilised for the first time and that it could be stored at 4°C with almost no change in its activity for a period of 180 days.

Daidzein, its effects on impaired glucose and lipid metabolism and vascular inflammation associated with type 2 diabetes

Over the last decades, the incidence of type 2 diabetes (T2D) is increasing substantially. Emerging evidences from epidemiological studies have shown the association between higher intake of soy isoflavones and reduced risk of T2D and its associated health risks. Daidzein, a soy isoflavone, has been found to have a promising therapeutic potential in managing T2D pathophysiology. Fermented soybean is the major source of daidzein; however, it can also be formed via the consumption of its glycosylated moiety, daidzin with subsequent hydrolysis by intestinal bacterial enzyme. Many studies reported the prophylactic effect of daidzein on the improvement of hyperglycemia, insulin resistance, dislipidemia, obesity, inflammation, and other complications associated with T2D. The molecular mechanisms underlying the action of daidzein include diverged pathways where daidzein has been shown to interact with several signaling molecules and receptors to achieve desirable effect. Although the specific molecular mechanism is still elusive, further studies are thus needed to understand it in detail. In this review, we discuss the antidiabetic potential of daidzein with respect to the evidences from various clinical, preclinical, and cell culture studies and the underlying molecular mechanism in a precise way to have a comprehensive account on this isoflavone with promising therapeutic potential.

Role of Plant: Microbe Interactions in the Sustainable Development of Muga Sericulture

In recent decades, increased agricultural production leads to intensive use of agrochemicals. This has affected the ecosystem stability. Biological control is one such alternative which supplements the use of chemical fertilizer, prevents the plant diseases, and promotes the health of the plants. In Muga sericulture, a Som plant (Machilus bombycina) is used as primary host plants of Muga silkworm (Antheraea assama, Helfer). A study has been made to improve the quality and quantity production of silk fiber using bacteria as a biocontrol agent and production of antibacterial peptides using Muga silkworm as a model insect for the control of Pseudomonas aeruginosa, a causative agent of flacherie disease in Muga silkworm. This study could be exploited in improvement of silk production and biocontrol of flacherie disease.