Shanthy Sundaram

Role of human papillomavirus and its detection in potentially malignant and malignant head and neck lesions: updated review

Head and neck malignancies are characterized by a multiphasic and multifactorial etiopathogenesis. Tobacco and alcohol consumption are the most common risk factors for head and neck malignancy. Other factors, including DNA viruses, especially human papilloma virus (HPV), may also play a role in the initiation or development of these lesions. The pathways of HPV transmission in the head and neck mucosal lesions include oral-genital contact, more than one sexual partner and perinatal transmission of HPV to the neonatal child. The increase in prevalence of HPV infection in these lesions may be due to wider acceptance of oral sex among teenagers and adults as this is perceived to be a form of safe sex. The prevalence of HPV in benign lesions as well as malignancies has been assessed by many techniques. Among these, the polymerase chain reaction is the most sensitive method. Review of literature reveals that HPV may be a risk factor for malignancies, but not in all cases. For confirmation of the role of HPV in head and neck squamous cell carcinoma, large population studies are necessary in an assortment of clinical settings. Prophylactic vaccination against high-risk HPV types eventually may prevent a significant number of cervical carcinomas. Of the two vaccines currently available, Gardasil® (Merck & Co., Inc.) protects against HPV types 6, 11, 16 and 18, while the other vaccine, Cervarix® (GlaxoSmithKline, Rixensart, Belgium) protects against HPV types 16 and 18 only. However, the HPV vaccine has, to the best of our knowledge, not been tried in head and neck carcinoma. The role of HPV in etiopathogenesis, prevalence in benign and malignant lesions of this area and vaccination strategies are briefly reviewed here.

Genetic polymorphisms of matrix metalloproteinases and their inhibitors in potentially malignant and malignant lesions of the head and neck

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases that are capable of cleaving all extra cellular matrix (ECM) substrates. Degradation of matrix is a key event in progression, invasion and metastasis of potentially malignant and malignant lesions of the head and neck. It might have an important polymorphic association at the promoter regions of several MMPs such as MMP-1 (-1607 1G/2G), MMP-2 (-1306 C/T), MMP-3 (-1171 5A/6A), MMP-9 (-1562 C/T) and TIMP-2 (-418 G/C or C/C). Tissue inhibitors of metalloproteinases (TIMPs) are naturally occurring inhibitors of MMPs, which inhibit the activity of MMPs and control the breakdown of ECM. Currently, many MMP inhibitors (MMPIs) are under development for treating different malignancies. Useful markers associated with molecular aggressiveness might have a role in prognostication of malignancies and to better recognize patient groups that need more antagonistic treatment options. Furthermore, the introduction of novel prognostic markers may also promote exclusively new treatment possibilities, and there is an obvious need to identify markers that could be used as selection criteria for novel therapies. The objective of this review is to discuss the molecular functions and polymorphic association of MMPs and TIMPs and the possible therapeutic aspects of these proteinases in potentially malignant and malignant head and neck lesions. So far, no promising drug target therapy has been developed for MMPs in the lesions of this region. In conclusion, further research is required for the development of their potential diagnostic and therapeutic possibilities.

Antioxidant Activity and Protective effect of Banana Peel against Oxidative Hemolysis of Human Erythrocyte at Different Stages of Ripening

Phytochemicals such as polyphenols and carotenoids are gaining importance because of their contribution to human health and their multiple biological effects such as antioxidant, antimutagenic, anticarcinogenic, and cytoprotective activities and their therapeutic properties. Banana peel is a major by-product in pulp industry and it contains various bioactive compounds like polyphenols, carotenoids, and others. In the present study, effect of ripening, solvent polarity on the content of bioactive compounds of crude banana peel and the protective effect of peel extracts of unripe, ripe, and leaky ripe banana fruit on hydrogen peroxide-induced hemolysis and their antioxidant capacity were investigated. Banana (Musa paradisica) peel at different stages of ripening (unripe, ripe, leaky ripe) were treated with 70% acetone, which were partitioned in order of polarity with water, ethyl acetate, chloroform (CHCl3), and hexane sequentially. The antioxidant activity of the samples was evaluated by the red cell hemolysis assay, free radical scavenging (1,1-diphenyl-2-picrylhydrazyl free radical elimination) and superoxide dismutase activities. The Folin–Ciocalteus reagent assay was used to estimate the phenolic content of extracts. The findings of this investigation suggest that the unripe banana peel sample had higher antioxidant potency than ripe and leaky ripe. Further on fractionation, ethyl acetate and water soluble fractions of unripe peel displayed high antioxidant activity than CHCl3 and hexane fraction, respectively. A positive correlation between free radical scavenging capacity and the content of phenolic compound were found in unripe, ripe, and leaky ripe stages of banana peel.

Centchroman mediated apoptosis involves cross-talk between extrinsic/intrinsic pathways and oxidative regulation

AIMS Centchroman (CC) has been established as a potent antineoplastic agent in MCF-7 (ER+ve) and MDA MB-231 (ER-ve) Human Breast Cancer Cells (HBCCs) previously by us. To elucidate its antineoplastic action, we investigated the factors involved in cell-cycle progression and apoptosis. MAIN METHODS Tamoxifen (TAM), a widely used antiestrogen was employed as a positive control. Role of Cycloheximide (CHX), Actinomycin-D (Act-D) and caspases were explored using specific inhibitors. Involvement of cell-cycle and apoptosis related factors were explored using western blotting and immunoprecipitation. KEY FINDINGS Metabolic inhibitors viz. CHX, Act-D and pan-Caspase inhibitor, Z-VAD-FMK attenuated CC-induced apoptosis. The upregulation of both p21(Waf1/Cip1) and p27(Kip1) along with p21-CDK6 (Cyclin Dependent Kinase 6) and p21-PCNA (Proliferating Cell Nuclear Antigen) interaction suggests their role in CC-induced cell-cycle arrest. The downregulation of Cyclin-D(1) and -E levels further confirms the antiestrogenic profile of CC. Unlike MDA MB-231, in MCF-7 cells, CC upregulates the level of phospho-p53 (Ser-15) and FasL, suggesting the involvement of extrinsic pathway. CC altered the intracytosolic balance of members of Bcl-2 family along with the cleavage of Poly (ADP-ribose) polymerase (PARP), Bcl-X(L), Bid and AIF (Apoptosis Inducing Factor). The evaluation of Mitogen Activated Protein Kinases (MAPKs) using specific inhibitors and Western blotting confirms CC-induced the upregulation of phospho-c-Jun and phospho-p38. Additionally elevated SOD (Superoxide Dismutase) and unaltered CAT (Catalase) expression further suggest the involvement of oxidative stress. SIGNIFICANCE These results confirm that the antineoplasticity of CC in MCF-7 and MDA MB-231 cells involves the extrinsic and intrinsic pathways of apoptosis along with oxidative stress.

Red luminescent manganese-doped zinc sulphide nanocrystals and their antibacterial study

Water soluble, uniform-sized ZnS:Mn2+ nanocrystals (NCs) have been prepared using a simple co-precipitation method with a methanol and water binary mixture as a reaction medium. The structure of the prepared ZnS:Mn2+ NCs is cubic with a mean size distribution of 3-5 nm. Photoluminescence (PL) studies showed emission at ∼612 nm, which is 22 nm red shifted as compared with the reported literature. This red shift could be attributed to the observed distortion in the imaged lattice plane. The capping effect of pepsin, citric acid and biotin on the optical properties of ZnS:Mn2+ NCs has been examined and the maximum enhancement in PL Intensity was found in the case of biotin. The synthesised ZnS:Mn2+ NCs were characterized by X-ray Diffraction (XRD), transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS) for investigation of their structural properties. Because of the high PL intensity, biotin capped ZnS:Mn2+ NCs were further investigated for their anti-bacterial activity against gram negative and gram positive bacteria. These NCs show broad spectrum antibacterial activity against both types of bacteria having an MIC value of 100 ng ml-1 for B. subtilis.

Evaluation and sensitivity of cyanobacteria, Nostoc muscorum and Synechococcus PCC 7942 for heavy metals stress – a step toward biosensor

This study attempted to determine the effects of heavy metals on the photosynthetic blue-green algae for their potential to use as a biosensor. The bioaccumulation of metals and its effects on pigments of Nostoc muscorum and Synechococcus PCC 7942 were assessed. The culture was grown in BG 11 liquid medium supplied with different metals like mercury (Hg), lead (Pb), and cadmium (Cd) and incubated (µM 20 concentrations) for 10 days under optimal conditions. The accumulated amounts of metals were determined by atomic absorption spectroscopy (AAS). The stress effects on photosynthetic pigment chlorophyll a (Chl a) were monitored by laser-induced fluorescence (LIF). Bio-concentration factor (BCF) reached a peak in cells on the 2nd day of incubation followed by a gradual reduction. The highest reduction in the pigment concentrations (Chl a and β carotene) was observed at 20 µM L−1 Hg treatment. The results indicate that, cyanobacteria may serve as both potential species to be used as a biosensor and used to clean up heavy metals from contaminated water. These changes were analyzed with the long-term goal of exploiting cyanobacterial cells as biosensors.

Carbon-Concentrating Mechanism

Every living molecular machine on planet is constructed across a middle staging of organic carbon which locked in extremely oxidized structures, such as carbonate minerals (calcite, aragonite, etc.) and CO2 gas. The photosynthetic organisms are capable to unlock these oxidized carbon structures and transform them into more organic forms via a process called “photosynthesis.” Among photosynthetic organisms, photosynthetic microorganisms play a significant role in the formation of organic biomass and oxygenic environment on Earth. However, majority of these microorganisms undertake photosynthesis in an aquatic environment of ocean where they face a number of unique restraints regarding the efficient operation of carbon fixation through photosynthesis. Carbon-concentrating mechanism (CCM) is a remarkable adaptation, evolved to maximize photosynthetic efficiency of many photosynthetic organisms in low-CO2 levels of aqueous environment. This chapter provides in-depth state-of-the-art information of CCM machinery.

A gp63 based vaccine candidate against Visceral Leishmaniasis

Visceral leishmaniasis is a macrophage associated disorder which leads to a profound decrease in the natural immunotherapeutic potential of the infected subjects to combat the disease. The major surface glycoprotein gp63 has been found to be a significant vaccine candidate against visceral leishmaniasis. The current study addresses the levels of similarity and identity in the gp63 obtained from different species of Leishmania viz donovoni, chagasi and infantum linked to the cause of visceral leishmaniasis. The results from BLAST, Phylogram and Cladogram studies indicate significant identity, similarity and conservation of important residues in the protein which lead us to conclude that a common gp63 based vaccine can be used as a therapeutical tool against visceral leishmaniasis caused by different species strains of leishmania.

Evaluation of promising algal strains for sustainable exploitation coupled with CO2 fixation

ABSTRACT The photosynthetic activity of three microalgae, Chlamydomonas reinhardtii, Chlorella AU1, Scenedesmus AU1, and six cyanobacteria, Spirulina platensis, Anabaena cylindrica, Oscillatoria AU1, Nostoc muscurum, Synechococcus AU1, Synechocystis sp. PCC6803, was investigated. Strains S. platensis, Scenedesmus AU1 sp. and Chlorella AU1 sp. showed the highest fluorescence quenching than other strains tested. Thus, these were selected for mitigation analysis in a designed tubular photobioreactor system at 0.06%, 6%, 12%, 18% and 24% concentrations. Spirulina showed maximum biomass productivity of 1.03 g L−1 d−1 with the highest fixation rate of 0.678 g  L−1 d−1 at 6% concentration. The maximum protein content (66.63%) was also achieved in Spirulina sp. at 6% concentration. Thus, Spirulina could be utilized as a source of protein supplement coupled with fixation. Maximum carbohydrate proportion (51.71%) was noted with Scenedesmus AU1 sp. at 12% . Scenedesmus AU1 sp. also accumulated the maximum lipid content (25.07%) at 6% concentration, which was further analysed for biodiesel production. The extracted Scenedesmus oil was mainly rich in short chain fatty acids (C-16 : 0, C-18:1, C-18:2, C-18:3) which is an ideal combination for efficient biodiesel. Thus, this is vital in helping to choose Scenedesmus as a biodiesel feedstock, coupled with fixation.

Recent advances in CO2 uptake and fixation mechanism of cyanobacteria and microalgae

ABSTRACT Aquatic photosynthetic microorganisms, cyanobacteria and microalgae, account for almost half of the worlds photosynthesis. They absorb carbon di oxide (CO2) as the major substrate to support photosynthesis, the beginning of energy flow into living organisms and one of the primary processes comprising the global carbon cycle. Among all photosynthetic mechanisms, inorganic carbon transport into ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is one of the major limiting steps in photosynthetic carbon fixation which involves active transport of HCO3−, CO2 and/or H+, or an energized biochemical mechanism. In fact, a unique system “carbon concentrating mechanism (CCM)” manages the inorganic carbon assimilation, accumulation of CO2 around RuBisCO, and utilization in algal cells. However, the information on mechanism of CO2 uptake and fixation inside the algal cells is limited. In order to make strategies for enhancement of CO2 fixation, understanding of CCM is crucial. Thus, this review provides an overview of advances in CCM research, the comparative state of the art and reports on the CO2 uptake model in cyanobacteria and microalgae. The review also discusses the challenges and future perspectives associated with algal CCM research.