Ayesha S. Ali

Epidemiological and etiological study of oral submucous fibrosis among gutkha chewers of Patna, Bihar, India

An etiological and epidemiological study of oral submucous fibrosis (OSMF) has been done in Patna, Bihar. Total 157 cases of OSMF and 135 control subjects were selected for study in the period of 2002-2004. It was observed that Male:Female ratio was 2.7:1. The youngest case of OSMF was 11 year old and the oldest one was 54 years of age. Maximum number of cases were belonging to 21-40 years of age and they were belonging to low or middle socioeconomic class. Most of the OSMF cases used heavy spices and chillies, where as control mild spices and chillies. Gutkha was the most commonly used by the OSMF cases only 3 per cent did not use any gutkha or other areca nut product where as 80 per cent control did not have any chewing habit. The OSMF cases used gutkha and other products 2-10 pouches per day and kept in the mouth for 2-10 minutes and they were using since 2-4 years. Most of the OSMF cases kept gutkha in the buccal vestibule or they chewed and swallowed it, only a small number of patients chewed and spitted it out. It was also observed that OSMF developed on one side of the buccal vestibule where they kept the chew and other side was normal.

Microbial Tyrosinases: Promising Enzymes for Pharmaceutical, Food Bioprocessing, and Environmental Industry

Tyrosinase is a natural enzyme and is often purified to only a low degree and it is involved in a variety of functions which mainly catalyse the o-hydroxylation of monophenols into their corresponding o-diphenols and the oxidation of o-diphenols to o-quinones using molecular oxygen, which then polymerizes to form brown or black pigments. The synthesis of o-diphenols is a potentially valuable catalytic ability and thus tyrosinase has attracted a lot of attention with respect to industrial applications. In environmental technology it is used for the detoxification of phenol-containing wastewaters and contaminated soils, as biosensors for phenol monitoring, and for the production of L-DOPA in pharmaceutical industries, and is also used in cosmetic and food industries as important catalytic enzyme. Melanin pigment synthesized by tyrosinase has found applications for protection against radiation cation exchangers, drug carriers, antioxidants, antiviral agents, or immunogen. The recombinant V. spinosum tryosinase protein can be used to produce tailor-made melanin and other polyphenolic materials using various phenols and catechols as starting materials. This review compiles the recent data on biochemical and molecular properties of microbial tyrosinases, underlining their importance in the industrial use of these enzymes. After that, their most promising applications in pharmaceutical, food processing, and environmental fields are presented.

Histamine receptors in the skin melanophores of Indian bullfrog Rana tigerina

Histamine and 2-methyl histamine caused dose-dependent aggregation of the integumental melanophores of Rana tigerina both in vitro and in vivo. The aggregating effects were antagonised by mepyramine and metiamide, specific H1 and H2 receptor blockers, respectively. Compound 48/80 and EDTA augmented the melanin-aggregating effects of exogenously applied histamine and 2-methyl histamine in in vivo experiments. 4-Methyl histamine, a specific H2 receptor agonist, dispersed the frog melanophores in in vitro studies, the dispersing effects were blocked by metiamide.

Purification and Characterization of Melanogenic Enzyme Tyrosinase from Button Mushroom

Melanogenesis is a biosynthetic pathway for the formation of the pigment melanin in human skin. A key enzyme, tyrosinase, catalyzes the first and only rate-limiting steps in melanogenesis. Since the discovery of its melanogenic properties, tyrosinase has been in prime focus and microbial sources of the enzyme are sought. Agaricus bisporus widely known as the common edible mushroom, its taking place in high amounts of proteins, enzyme, carbohydrates, fibers, and low fat contents are frequently cited in the literature in relation to their nutritional value. In the present study tyrosinase from Agaricus bisporus was purified by ammonium sulphate precipitation, dialysis followed by gel filtration chromatography on Sephadex G-100, and ion exchange chromatography on DEAE-Cellulose; the enzyme was purified, 16.36-fold to give 26.6% yield on total activity in the crude extract and final specific activity of 52.19 U/mg. The SDS-PAGE electrophoresis showed a migrating protein band molecular weight of 95 kDa. The purified tyrosinase was optimized and the results revealed that the optimum values are pH 7.0 and temperature 35°C. The highest activity was reported towards its natural substrate, L-DOPA, with an apparent Km value of 0.933 mM. This indicated that tyrosinase purified from Agaricus bisporus is a potential source for medical applications.

In vitro responses of fish melanophores to lyophilized extracts of Psoralea corylifolia seeds and pure psoralen

Context: Psoralens are naturally occurring furanocumarins used in photochemotherapy of several skin diseases. They are obtained from dried ripe fruits of Psoralea corylifolia Linn. (Fabaceae). However, little research has been done to study the melanogenic activity of P. corylifolia seeds and their active ingredients on the pigment cells, the melanophores taking account of their cholinergic activity. Objective: The present work was carried out to determine the effects of lyophilized seed extracts of P. corylifolia, along with pure psoralen on the isolated scale melanophores of Channa punctatus Bloch. (Channidae), which are a disguised type of smooth muscle cells and offer excellent in vitro opportunities for studying the effects of drugs. Materials and methods: Effects of lyophilized extracts of P. corylifolia and pure psoralen were studied on the isolated scale melanophores of C. punctatus as per the modified method of . Results: The lyophilized extract of P. corylifolia and its active ingredient psoralen caused significant melanin dispersal responses leading to darkening of the fish scale melanophores, which were completely antagonized by atropine and hyoscine. These melanin dispersal effects were also found to be markedly potentiated by neostigmine, an anticholinesterase agent. Discussion: In the present study, the lyophilized extract of P. corylifolia seeds and standard psoralen in different dose ranges induced powerful melanin dispersal effects of the previously adrenaline-aggregated isolated scale melanophores of C. punctatus. Comparatively, psoralen caused a more sustained and powerful melanin dispersal within the isolated fish melanophores and interestingly the concentrations required to achieve maximal dispersion of melanophore were 10 times less than that of lyophilized seed extract of P. corylifolia. The physiologically significant dose-related melanin dispersion effects of lyophilized P. corylifolia seeds and synthetic psoralen per se were found to be completely abolished by atropine and hyoscine, which are specific cholino-muscarinic receptor blockers. These data strongly indicate that in the fish C. punctatus, the dispersion of melanin granules within the scale melanophores is mediated by choline receptors of muscarinic nature. Conclusion: It appears that the melanin dispersal effects of the extracts of P. corylifolia and pure psoralen leading to skin darkening are mediated by cholino-muscarinic- or cholino-psoralen-like receptors having similar properties.

5‐HT receptors as novel targets for optimizing pigmentary responses in dorsal skin melanophores of frog, Hoplobatrachus tigerinus

BACKGROUND AND PURPOSE Biochemical identification of 5‐HT has revealed similar projection patterns across vertebrates. In CNS, 5‐HT regulates major physiological functions but its peripheral functions are still emerging. The pharmacology of 5‐HT is mediated by a diverse range of receptors that trigger different responses. Interestingly, 5‐HT receptors have been detected in pigment cells indicating their role in skin pigmentation. Hence, we investigated the role of this monoaminergic system in amphibian pigment cells, melanophores, to further our understanding of its role in pigmentation biology together with its evolutionary significance.

Melanogenic effect of purified mushroom tyrosinase on B16F10 Melanocytes: A Phase Contrast and Immunofluorescence Microscopic Study

Cutaneous melanin pigment plays a critical role in camouflage, mimicry, social communication, and protection against harmful effects of solar radiation. It has been proven that tyrosinase plays a pivotal role in melanocytes dendrite formation; however, the molecular mechanism underlying this process has not been fully elucidated. The morphological changes were observed under a phase contrast microscope. These changes were evident, with globular cell bodies and increased numbers of tree branch-like dendrites. The present work aimed to study the morphoanatomic effects of purified tyrosinase to determine its skin-darkening potential using B16F10 melanocyte, which has not been done to date. Phase contrast and immunofluorescence microscopic analysis of B16F10 melanocytes has been done after treatment with various concentrations of purified tyrosinase along with standard tyrosinase (Sigma) in order to explore the mechanism of action of purified tyrosinase induced skin darkening. The phase contrast microscopic results showed that the number of melanocytes with melanin-loaded dendrites has increased significantly in purified tyrosinase treated cells in a dose dependent manner leading to skin darkening. In addition, immunofluorescence microscopic analysis revealed purified tyrosinase increase cellular tyrosinase expression in doze dependent manner due to tyrosinase absorption in B16F10 melanocyte. Present findings proved that purified tyrosinase possesses a skin darkening potential and could be used as a safe melanogenic agent for the treatment of hypopigmentation disorders or vitiligo.

Recent Updates in Melanocyte Function: The Use of Promising Bioactive Compounds for the Treatment of Hypopigmentary Disorders

BACKGROUND Skin pigmentation is a broadly appearing phenomenon in nature which plays an important task of determining the appearance and biology of all vertebrates including human beings. Skin color is a crucial attribute, determined by the synthesis of melanin pigment within melanocytes by the process of melanogenesis and is regulated by many extrinsic as well as intrinsic factors. Tyrosinase catalyzes the key step of melanogenesis, dysfunction of tyrosinase leads to reduce melanin production which results in severe clinical and aesthetical problems of hypopigmentation. Therefore, the regulation of melanin production is an important strategy in the treatment of abnormal skin pigmentation for cosmetic and medicinal purpose. METHOD The present review covers the various aspects of mammalian melanocyte biology which will help in the identification of key regulators of melanogenesis from pharmaceutical and pharmacological point of view. Further sections of the review focus on the dysfunctions of melanogenic pathways, which result in severe clinical and aesthetical problems of hypopigmentation. CONCLUSION We have also attempted to highlight the ability of available scientifically validated plant extracts to naturally enhance melanin synthesis in order to cure hypopigmentation.

5-HT receptor subtypes as key targets in mediating pigment dispersion within melanophores of teleost, Oreochromis mossambicus.

The presence of distinct class of 5-HT receptors in the melanophores of tilapia (Oreochromis mossambicus) is reported. The cellular responses to 5-HT (5-hydroxytryptamine), 5-HT(1), and 5-HT(2), agonists on isolated scale melanophores were observed with regard to pigment translocation within the cells. It was found that 5-HT exerted rapid and strong concentration dependent pigment granule dispersion within the melanophores. The threshold pharmacological dose of 5-HT that could elicit a measurable response was as low as 4.7×10(-12) M/L. Selective 5-HT(1) and 5-HT(2) agonists, sumatriptan and myristicin were investigated and resulted in dose-dependent pigment dispersion. The dispersing effects were effectively antagonized by receptor specific antagonists. It is suggested that 5-HT-induced physiological effects are mediated via distinct classes of receptors that possibly participate in modulation of pigmentary responses of the fish.

Microsatellite-based genetic evaluation of Ghumusar goats of Orissa, India

Summary Ghumusar is an inadequately studied goat population of western region of Ganjam district of Orissa state. Sporadic information is available on its morphological traits but no information is found on its genetic variability. Therefore, an attempt was made to measure the genetic diversity in Ghumusar goat population using 25 microsatellite markers. Genomic DNA isolated from blood samples drawn at random from 50 individuals were utilized for this study. The average number of observed allele was 9.80 and the effective average number of allele was 4.28. The polymorphic information contents ranged from 0.53 to 0.91. The average observed and expected heterozygosity was 0.73 and 0.71, respectively. The values of Nei’s gene diversity in Ghumusar goat population ranged from 0.11 to 0.87 with a mean of 0.69. The overall Fis value was observed to be 0.002, which is not significantly different from zero; hence indicating no global deficit of heterozygotes. Under sign test, expected number of loci with heterozygosity excess (Hee) was 14.88, 14.79 and 14.74 for the infinite allele model (IAM), stepwise mutation model (SMM) and two-phased model (TPM) of mutation, respectively. The observed number of loci with heterozygotic excess (He) was 14, 8 and 2 under these three models, respectively. Under all the three models, He was less than Hee and this deviation was significant under SMM and TPM models. There was no serious genetic reduction in effective population size as indicated by L-shaped curve in Ghumusar goat population.