2058 research outputs found
Sort by
Role of matrix metalloproteinases and cytokines during Helicobacter pylori infection
No full textThe possible existence of bacteria in human stomach was believed for more than a century. These bacteria, however, were thought to be ingested from food rather than
true gastric colonizers. By the late 19th and early 20th centuries, several investigators had reported the presence of spiral microorganisms in the stomach of animals and
human (Kusters, van Vliet et al. 2006). In 1989, Walery Jaworski described spiral organisms in sediment washings of humans. He suggested that these organisms might be
involved with gastric disease (Kidd and Modlin 1998). In 1892, Giulio Bizzozero observed spiral organisms in the stomach of dogs (Mazzarello, Calligaro et al. 2001). Soon afterward, similar spiral bacteria were observed in humans who had peptic ulcer disease or gastric cancer (Krienitz 1906). Although, throughout most of the 20th century, peptic ulcer disease was thought to be a chronic, incurable disease caused by gastric juice corroding vulnerable mucosa; and neutralization of gastric acid was the
mean of disease management. About 20 years ago, Barry Marshall and Robin Warren described the successful isolation and culture of a spiral bacterial species, later known as Helicobacter pylori, from the human stomach (1983). The isolation of curved bacilli from patients with chronic gastritis sparked revolutions in the fields of
gastroenterology, microbiology and molecular biology. Self-ingestion experiments by Marshall (Marshall, Armstrong et al. 1985) and Warren and later experiments with
volunteers (Morris, Ali et al. 1991) demonstrated that these bacteria can colonize the human stomach, thereby inducing inflammation of the gastric mucosa. The etiological
role of these bacteria in the development of peptic ulcer disease and gastric cancer was considered at that time, and patients were sometimes even treated with high doses of
the antimicrobial compound bismuth (Kusters, van Vliet et al. 2006). Although the initial cultures from patients were negative, accidentally one culture was incubated for 5 days over an Easter holiday and the first colonies were observed in 1982 (Marshall and Warren 1984). They contested the prevailing notion by showing that peptic ulcer
disease is an infectious disease caused by H. pylori. For this revolutionary work, Marshall and Warren were awarded the 2005 Nobel Prize for Physiology or Medicine. The
organism was initially named “Campylobacter- like organism,
Synthetic, structural, electrochemical and DNA-binding aspects of a novel oximato bridged copper(II) dimer
No full textA dimeric double oximato-bridged (l1,2-N-O) Cu(II) complex, [Cu2L2(ClO4)2]�2H2O (1), was synthesized from the reaction of equimolar proportion of a novel Schiff base ligand, 1-phenyl-1-(pyridin-2-yl-hydrazono)- propan-2-one oxime (LH), and copper(II)perchlorate hexahydrate in methanol. C, H and N microanalyses, gravimetric copper estimation, FT-IR, UV–Vis (solid state as well as in solution), ESI-MS spectra,
molar electric conductivity, EPR and room temperature magnetic susceptibility measurements were performed
to characterize 1. The X-ray crystal structure of 1 shows that each copper center in 1 is in ‘N3O2’ coordination environment with a Cu� � �Cu separation of 3.595 Å. 1 follows unique two-step mono-electronic oxidative steps in its CV in methanol. ESI-MS spectrum of 1 indicates that the dimeric core unit retains its identity in solution as well. Interaction of 1 with Calf thymus (CT) DNA was studied by spectroscopic and calorimetric techniques. The mode of binding was investigated by ethidium bromide displacement
assay. This binding enhanced the stabilization of the DNA structure against thermal strand separation. The magnitudes of the association constant as derived from spectroscopic and calorimetric studies are in good harmon
Studies on the role of Eph/Ephrin signaling in chemo-resistance property of mutant p53 bearing human cancers
No full textCancer is a complex disease that kills millions of people annually. Alterations in genetic and epigenetic cellular programs derail cellular controls normally responsible for maintaining homeostasis. Sequencing of human cancer genomes has identified a myriad of genomic alterations found in human cancers. Alterations in the TP53 tumor suppressor gene stand out as the most common alteration in many cancers. The functional importance of p53 as a tumor suppressor gene is evident through its pervasiveness in cancer biology. The TP53 gene is the most commonly altered gene in human cancer; however, not all genetic alterations are biologically equivalent. The majority of alterations involve p53 missense mutations that result in the production of mutant p53 proteins. Such mutant p53 proteins lack normal p53 function and may concomitantly gain novel functions, often with deleterious effects. Gain-of-function mutant p53 acquire selective growth advantage and tumorigenic potential. Indeed, mutant p53 protein was found to promote most of the events involved in the malignancy process
Genetic and epigenetic signature of matrix metalloproteinase and tissue inhibitor of metalloproteinases and their association with risk of gastric carcinoma
No full textCancer (medical term: malignant neoplasm) is a disease of uncontrolled cellular growth, invasion that sometimes spread to other locations in the body via lymph or
blood. Six potential alterations occur in cell physiology during cancer progression: (a) self support in growth signals (b) insensitivity to growth-inhibitory signals (c)
escape from apoptosis (d) infinite replication (e) sustained angiogenesis and (f) tissue invasion and metastasis (Hanahan and Weinberg 2011, 2000). Tumor cells
follow a multistep process namely: tumor cell detachment, local invasion, cell motility, angiogenesis, vessel invasion, survival in circulation, adhesion to
endothelial cells, extravasation and regrowth in different organs during metastasis (Hanahan and Weinberg 2000). Stomach cancer or gastric cancer is developed from
the lining of the stomach and found most often in people of older age. The disease affects men twice as often as women. Although the overall incidence rate of gastric
cancer is declining over the last several decades however, gastric cancer remains the forth most common type of cancer and is the second leading cause of cancerrelated
death worldwide (Jemal et al. 2011; Bertuccio et al. 2009). The steady decline in the incidence and mortality of stomach cancer in most developed countries is due to changes in nutrition pattern, improvement in food storage,
advanced treatment and control of H. pylori infection (Jarosz et al. 2011; Amiri, Janssen, and Kunst 2011; Zhu and Sonnenberg 2012; Katanoda and Yako-Suketomo 2009; Bertuccio et al. 2009). Early gastric cancer symptoms may be associated with indigestion or a burning sensation (heartburn), which most of the cases remain neglected in developing countries. However, about 2% referred for
endoscopy due to indigestion are diagnosed as gastric cancer. Unfortunately, in most of the cases, gastric cancer diagnose at late stage when the disease reaches in
an advanced stage (Maconi, Manes, and Porro 2008). Advanced or metastatic gastric cancer treatment achieved little progress with survival of less than 1 year (Wilke and Van Cutsem 2003)
Noninvasive Diagnosis of Visceral Leishmaniasis:Development and Evaluation of Two Urine-Based Immunoassays for Detection of Leishmania donovani Infection in India
Get PDFVisceral leishmaniasis (VL), one of the most prevalent parasitic diseasesin the developing world causes serious health concerns. Post kala-azar dermal leishmaniasis (PKDL) is a skin disease which occurs after treatment as a sequel to VL. Parasitological diagnosis involves invasive tissue aspiration which is tedious and painful. Commercially available immunochromatographic rapid diagnostic test such as rK39-RDT is used for field diagnosis of VL, detects antibodiesin serum samples. Urine sample is however, much easier in
collection,storage and handling than serum and would be a better alternative where collection of tissue aspirate or blood is impractical. In this study, we have developed and evaluated the performance of two urine-based diagnostic assays, ELISA and dipstick test, and
compared the results with serologicalrK39-RDT. Our study shows the capability of urinebased tests in detecting anti-Leishmania antibodies effectively for both VL and PKDL diagnosis. The ability of dipstick test to demonstrate negative results after six months in
90% of the VL cases after treatment could be useful as a test of clinical cure. Urine-based
tests can therefore replace the need for invasive practices and ensure better diagnosi
Studies on the Role of Matrix Metalloproteinases and their Inhibitors in the Pathogenesis of Endometriosis
No full textEndometriosis is a gynecological disease, where endometrium-like lesions develop outside uterus. This inflammatory disease affects ~10% of reproductive women worldwide, resulting in severe pelvic pain and infertility. The etiology of endometriosis remains unknown. In the present study, we looked into the involvement of a group of zinc-dependent endopeptidases, known as matrix metalloproteinase (MMP) in the pathogenesis of endometriosis. In one chapter, the role of MMP-2 on endometriosis was studied. We report that ovarian endometriosis progression is associated with angiogenesis, alongwith elevated MMP-2 activity and reduced tissue inhibitor of metalloproteinses (TIMP)-2 expressions. When investigated in human endothelial cells, we found the upregulated MMP-2 activities and increased endothelial tube formation were regulated by prostaglandinE2 (PGE2) through COX-2/PGE2/pAKT axis. Inhibition of specific MMP-2 activity attenuated tube formation in endothelial cells and angiogenesis in chick chorioallantoic membrane assay. In another chapter, involvement MMP-1 was studied in ovarian endometriosis and found to be elevated with disease progression, while expressions for TIMP-3 downregulated. Treatments with interleukin-1β or PGE2 elevated MMP-1 expressions in endometriotic cell line (HS-832). Moreover, PGE2 and IL1β together elevated MMP-1 expressions as well as cellular invasiveness in a synergistic manner. Studies with inhibitors for specific mitogen activated protein kinase (MAPK) pathways proved that MMP-1 expression is regulated by cJUN N-terminal kinase (JNK)-activator protein (AP)-1 pathway. Furthermore, SiRNA-mediated silencing of cJUN confirmed JNK-pcJUN mediated regulation for MMP-1 expressions, as well as cellular invasiveness. In the next chapter, we utilized mouse model of endometriosis to look into disease pathogenesis and therapeutic efficacy of curcumin. Day dependent study of endometriosis showed functional endometriosis-like gland development within mouse peritoneum, with elevated MMP-1,-2,-9,-3 and -14 responses. Treatment with curcumin significantly downregulated the reported MMP expressions, except MMP-1. Curcumin regressed in vivo endometriotic lesions and glands by inducing severe mitochondria-mediated apoptosis, alongwith elevated caspases, p21, p53 and p38 responses. In summary, the present thesis explored the involvement of MMP-1 and MMP-2 in pathogenesis of ovarian endometriosis in clinical and in vitro studies, and efficacy of curcumin as an anti-endometriotic agent for in vivo model of endometriosis
Non-mulberry Silk Fibroin Biomaterial for Corneal Regeneration
Get PDFSuccessful repair of a damaged corneal surface is a great challenge and may require the use of a scaffold that supports cell growth and differentiation. Amniotic membrane is currently used for this purpose, in spite of its limitations. A thin transparent silk fibroin film from non-mulberry Antheraea mylitta (Am) has been developed which offers to be a promising alternative. The silk scaffolds provide sufficient rigidity for easy handling, the scaffolds support the sprouting, migration, attachment
and growth of epithelial cells and keratocytes from rat corneal explants; the cells form a cell sheet,
preserve their phenotypes, express cytokeratin3 and vimentin respectively. The films also support growth of limbal stem cell evidenced by expression of ABCG2. The cell growth on the silk film and the amniotic membrane is comparable. The implanted film within the rabbit cornea remains transparent, stable. The clinical examination as well as histology shows absence of any inflammatory response or neovascularization. The corneal surface integrity is maintained; tear formation, intraocular pressure and electroretinography of implanted eyes show no adverse changes. The silk fibroin film from nonmulberry
silk worms may be a worthy candidate for use as a corneal scaffold
Role of Protein Conformational Landscape on its Aggregation
No full textProteins are typically large bio-molecules consisting of twenty-one different amino acid subunits. These amino acid subunits are covalently linked with one another to form long linear polypeptide chain which spontaneously fold to become compact three-dimensional structure. After folding, proteins can attain complex shapes that include clustering of various patterns, loops, coil and may contain some unstructured regions or disordered regions along with structured parts. Protein molecules show wide range of biological activities, which are necessary for living systems. These biological functions are determined by the three-dimensional structure of a protein and the protein structures are primarily determined by the constituting amino acid sequence. Thus, the diversity of protein function is primarily determined and controlled by the amino acid sequence of the protein. There can be an allowed range in sequence variation for a particular type of functional requirement of a protein. The deciding factors dictating the actual sequence composition out of the allowed range in sequence variation for a particular function are; protein solvent environment and the selection pressure imposed by natural selection process during evolution. The functional adaptation and the quality control of protein comes from the selective amino acids mutations approved by the natural selection. The approved sequence order of twenty-one different amino acids of a particular protein and the solvent condition faced by protein during and after the folding process, are the main key players that governs the different three-dimensional structure and function of a protein.
With varieties of functions, proteins are crucial elements in all biological organisms and participate in every process within the living cells. They are actively involved in physiological processes that govern cell division, cell growth, cell development, cell shape and structure, cell signaling, cell motility, ligand binding, cell immunity and enzyme catalysis etc. Variety of proteins including enzymes, antibodies, hormonal proteins, structural proteins, storage proteins and transport proteins are present in living cells; each of which fulfils a particular biological role. Their combined function makes a system alive and biologically active. Majority of these biological functions are performed by proteins in their native state. This state is relatively more
2
stable than other states with higher degrees of freedom like, unfolded and partially unfolded
intermediate states. The stability of the native state determines how long can a native state resist
the structural degradation and resulting its biological function. Different proteins have varying
degrees of structural stability and the variation in structural stability of a protein again depends
on its amino acid sequence. It is noticed that sequence variation may alter protein structure and
consequently its function, protein folding and stability
Surfactant modulated aggregation induced enhancement of emission (AIEE)—a simple demonstration to maximize sensor activity
No full textA new type of easily synthesized rhodamine-based chemosensor L3, with potential NO2 donor atoms,
selectively and rapidly recognizes Hg2+ ions in the presence of all biologically relevant metal ions and
toxic heavy metals. A very low detection limit (78 nM) along with cytoplasmic cell imaging applications with no or negligible cytotoxicity indicate good potential for in vitro/in vivo cell imaging studies. SEM and TEM studies reveal strongly agglomerated aggregations in the presence of 5 mM SDS which turn into isolated core shell microstructures in the presence of 9 mM SDS. The presence of SDS causes an enhanced quantum yield (φ) and stability constant (Kf ) compared to those in the absence of SDS. Again, the FI of the [L3–Hg]2+ complex in an aqueous SDS (9 mM) medium is unprecedentedly enhanced (∼143 fold) compared
to that in the absence of SDS. All of these observations clearly manifest in the enhanced rigidity of the [L3–Hg]2+ species in the micro-heterogeneous environment significantly restricting its dynamic movements. This phenomenon may be ascribed as an aggregation induced emission enhancement (AIEE). The fluorescence anisotropy assumes a maximum at 5 mM SDS due to strong trapping (sandwiching) of the doubly positively charged [L3–Hg]2+ complex between two co-facial laminar microstructures
of SDS under pre-miceller conditions where there is a strong electrostatic interaction that causes an improved inhibition to dynamic movement of the probe-mercury complex. On increasing the SDS concentration there is a phase transition in the SDS microstructures and micellization starts to prevail at SDS ≥ 7.0 mM. The doubly positively charged [L3–Hg]2+ complex is trapped inside the hydrophobic inner core of the micelle which is apparent from the failure to quench the fluorescence of the complex on adding 10 equivalents of H2EDTA2− solution but in the absence of SDS it is quenched effectively
A potent betulinic acid analogue ascertains an antagonistic mechanism between autophagy and proteasomal degradation pathway in HT-29 cells
Get PDFBetulinic acid (BA), a member of pentacyclic triterpenes has shown important biological activities like
anti-bacterial, anti-malarial, anti-inflammatory and most interestingly anticancer property. To overcome its poor
aqueous solubility and low bioavailability, structural modifications of its functional groups are made to generate
novel lead(s) having better efficacy and less toxicity than the parent compound. BA analogue, 2c was found most
potent inhibitor of colon cancer cell line, HT-29 cells with IC50 value 14.9 μM which is significantly lower than
standard drug 5-fluorouracil as well as parent compound, Betulinic acid. We have studied another mode of PCD,
autophagy which is one of the important constituent of cellular catabolic system as well as we also studied
proteasomal degradation pathway to investigate whole catabolic pathway after exploration of 2c on HT-29 cells.
Mechanism of autophagic cell death was studied using fluorescent dye like acridine orange (AO) and
monodansylcadaverin (MDC) staining by using fluorescence microscopy. Various autophagic protein expression
levels were determined by Western Blotting, qRT-PCR and Immunostaining. Confocal Laser Scanning Microscopy
(CLSM) was used to study the colocalization of various autophagic proteins. These were accompanied by formation
of autophagic vacuoles as revealed by FACS and transmission electron microscopy (TEM). Proteasomal degradation
pathway was studied by proteasome-Glo™ assay systems using luminometer.The formation of autophagic vacuoles in HT-29 cells after 2c treatment was determined by fluorescence
staining – confirming the occurrence of autophagy. In addition, 2c was found to alter expression levels of different autophagic proteins like Beclin-1, Atg 5, Atg 7, Atg 5-Atg 12, LC3B and autophagic adapter protein, p62. Furthermore we found the formation of autophagolysosome by colocalization of LAMP-1 with LC3B, LC3B with Lysosome, p62 with lysosome. Finally, as proteasomal degradation pathway downregulated after 2c treatment colocalization of ubiquitin
with lysosome and LC3B with p62 was studied to confirm that protein degradation in autophagy induced HT-29 cells
follows autolysosomal pathway. In summary, betulinic acid analogue, 2c was able to induce autophagy in HT-29 cells and as proteasomal degradation pathway downregulated after 2c treatment so protein degradation in autophagy induced HT-29 cell