Molten Globule of Hemoglobin Proceeds into Aggregates and Advanced Glycated End Products

Conformational alterations of bovine hemoglobin (Hb) upon sequential addition of glyoxal over a range of 0–90% v/v were investigated. At 20% v/v glyoxal, molten globule (MG) state of Hb was observed by altered tryptophan fluorescence, high ANS binding, existence of intact heme, native-like secondary structure as depicted by far-UV circular dichroism (CD) and ATR-FTIR spectra as well as loss in tertiary structure as confirmed by near-UV CD spectra. In addition, size exclusion chromatography analysis depicted that MG state at 20% v/v glyoxal corresponded to expanded pre-dissociated dimers. Aggregates of Hb were detected at 70% v/v glyoxal. These aggregates of Hb had altered tryptophan environment, low ANS binding, exposed heme, increased β-sheet secondary structure, loss in tertiary structure, enhanced thioflavin T (ThT) fluorescence and red shifted Congo Red (CR) absorbance. On incubating Hb with 30% v/v glyoxal for 0–20 days, advanced glycation end products (AGEs) were detected on day 20. These AGEs were characterised by enhanced tryptophan fluorescence at 450 nm, exposure of heme, increase in intermolecular β-sheets, enhanced ThT fluorescence and red shift in CR absorbance. Comet assay revealed aggregates and AGEs to be genotoxic in nature. Scanning electron microscopy confirmed the amorphous structure of aggregates and branched fibrils of AGEs. The transformation of α-helix to β-sheet usually alters the normal protein to amyloidogenic resulting in a variety of protein conformational disorders such as diabetes, prion and Huntington''s.     

A Novel Group of Moraxella catarrhalis UspA Proteins Mediates Cellular Adhesion via CEACAMs and Vitronectin

Moraxella catarrhalis (Mx) is a common cause of otitis media and exacerbation of chronic obstructive pulmonary disease, an increasing worldwide problem. Surface proteins UspA1 and UspA2 of Mx bind to a number of human receptors and may function in pathogenesis. Genetic recombination events in the pathogen can generate hybrid proteins termed UspA2H. However, whether certain key functions (e.g. UspA1-specific CEACAM binding) can be exchanged between these adhesin families remains unknown. In this study, we have shown that Mx can incorporate the UspA1 CEACAM1-binding region not only into rare UspA1 proteins devoid of CEACAM-binding ability, but also into UspA2 which normally lack this capacity. Further, a screen of Mx isolates revealed the presence of novel UspA2 Variant proteins (UspA2V) in ∼14% of the CEACAM-binding population. We demonstrate that the expression of UspA2/2V with the CEACAM-binding domain enable Mx to bind both to cell surface CEACAMs and to integrins, the latter via vitronectin. Such properties of UspA2/2V have not been reported to date. The studies demonstrate that the UspA family is much more heterogeneous than previously believed and illustrate the in vivo potential for exchange of functional regions between UspA proteins which could convey novel adhesive functions whilst enhancing immune evasion.     

Short-Term,Intermittent Fasting Induces Long-Lasting Gut Health and TOR-Independent Lifespan Extension

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Approximation of ground water quality for microbial and chemical contamination

Present study was designed to obtain estimation about ground water quality of Bhimber, Azad Jammu and Kashmir (AJK), Pakistan. A total of 12 water samples were collected from different localities of study area to analyze for various physicochemical and biological parameters i.e. namely temperature, pH, turbidity, color, odor, taste, electric conductivity (EC), total dissolved solids (TDS), total hardness (Calcium + Magnesium), chloride, arsenic, phosphate, lead, ammonium ion, nitrite, Fecal coliform and Escherichia coli. Results exposed that all ground water samples of study area were grossly contaminated with pathogenic microorganisms like E. coli and Fecal coliform except one water sample that was obtained from community filter plant Samahni Chowk site. Besides it, values of some physicochemical water quality determining parameters also deviated from recommended limits of World Health Organization (WHO). Chloride ion concentration was little below the prescribed limits in almost all water samples. It has been proven that consumption of un-safe drinking water is one of the major cause of prevalence of water borne diseases like diarrhea, gastroenteritis, typhoid fever and malaria etc. in study area. Community water supply and sanitation projects should be encouraged; government should provide filter plants in all regions of the country so that people could have easy approach to safe drinking water.     

Rosin Surfactant QRMAE Can Be Utilized as an Amorphous Aggregate Inducer: A Case Study of Mammalian Serum Albumin

Quaternary amine of diethylaminoethyl rosin ester (QRMAE), chemically synthesized biocompatible rosin based cationic surfactant, has various biological applications including its use as a food product additive. In this study, we examined the amorphous aggregation behavior of mammalian serum albumins at pH 7.5, i.e., two units above their isoelectric points (pI ~5.5), and the roles played by positive charge and hydrophobicity of exogenously added rosin surfactant QRMAE. The study was carried out on five mammalian serum albumins, using various spectroscopic methods, dye binding assay, circular dichroism and electron microscopy. The thermodynamics of the binding of mammalian serum albumins to cationic rosin modified surfactant were established using isothermal titration calorimetry (ITC). It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI. Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate. Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins. This study can be used for the design of novel biomolecules or drugs with the ability to neutralize factor(s) responsible for the aggregate formation, in addition to various other industrial applications.     

Meningococcal Opa and Opc proteins: their role in colonization and invasion of human epithelial and endothelial cells

Neisseria meningitidis (Nm) isolates from disease or during carriage express, on their outer membranes, one or more of a family of closely related proteins designated Opa proteins. In this study, we have examined the potential rotes of Nm Opa proteins in bacterial attachment and invasion of endothelial as well as epithelial cells and compared the influence of Opa proteins with that of Ope protein, which has been previously shown to increase bacterial interactions with eukaryotic cells. Several variants expressing different Opa proteins (A, B, D) or Opc were selected from a culture of capsule-deficient non-piliated bacteria of strain C751. Although the Opa proteins increased bacterial attachment and invasion of endothelial cells, Opc was the most effective protein in increasing bacterial interactions with these cells. In contrast, attachment to several human epithelial cells was facilitated at least as much by OpaB as Opc protein. OpaA was largely without effect whereas OpaD conferred intermediate attachment. OpaB also increased invasion of epithelial cells; more bacteria were internalized by Chang conjunctival cells compared with Hep-2 larynx carcinoma or A549 lung carcinoma cells. Monoclonal antibody reacting with OpaB inhibited bacterial interactions with the host cells. Opa-mediated interactions were also eliminated or significantly reduced in variants expressing capsule or those with sialylated lipopolysaccharide. These data are consistent with the notion that environmental factors controlling capsule and lipopolysaccharide phenotype may modulate bacterial interactions mediated by these OM proteins. In permissive microenvironments, some Opa proteins may be important in bacterial colonization and translocation in addition to Opc. The data also support the notion that Nm Opa may confer tissue tropism.     

Role of proline and glycinebetaine pretreatments in improving heat tolerance of sprouting sugarcane (<Emphasis Type="Italic">Saccharum</Emphasis> sp.) buds

High temperature strongly hampers the plant growth particularly at early growth stages. In this study, changes in some physiological and anatomical characteristics and possibility of mitigating the adversities of heat stress by soaking sugarcane nodal buds in 20 mM proline and glycinebetaine (GB) solutions have been explored. Heat stress reduced the rate of bud sprouting nonetheless soaking the setts in proline followed by GB was beneficial. In addition, heat stress reduced the bud fresh and dry weights, generated H₂O₂, reduced the tissue levels of K⁺ and Ca²⁺, while increased the osmolytes synthesis in a time course manner. Heat stress also delayed the emergence and expansion of new bud leaves, by restricting the number and area of mesophyll cells. It also caused poor and aberrant development and diffused appearance of mesophyll cells and vascular bundles in the bud leaves. However, soaking of buds in proline and GB solutions substantially reduced the H₂O₂ production, improved the accumulation of soluble sugars and protected the developing tissues from heat stress effects; although proline was more effective than GB. Correlations of various attributes indicated that soaking in GB and proline restricted the H₂O₂ generation, improved K⁺ and Ca²⁺ contents, and increased the concentrations of free proline, GB and soluble sugars eventually improving the heat tolerance of buds. Cost-benefit analysis showed that, considering increase in sprouting of buds, soaking in 20 mM solution of both osmoprotectants is economical.     

Stromal fibroblasts present in invasive human breast carcinomas promote tumor growth and angiogenesis through elevated SDF-1/CXCL12 secretion

Fibroblasts often constitute the majority of the stromal cells within a breast carcinoma, yet the functional contributions of these cells to tumorigenesis are poorly understood. Using a coimplantation tumor xenograft model, we demonstrate that carcinoma-associated fibroblasts (CAFs) extracted from human breast carcinomas promote the growth of admixed breast carcinoma cells significantly more than do normal mammary fibroblasts derived from the same patients. The CAFs, which exhibit the traits of myofibroblasts, play a central role in promoting the growth of tumor cells through their ability to secrete stromal cell-derived factor 1 (SDF-1); CAFs promote angiogenesis by recruiting endothelial progenitor cells (EPCs) into carcinomas, an effect mediated in part by SDF-1. CAF-secreted SDF-1 also stimulates tumor growth directly, acting through the cognate receptor, CXCR4, which is expressed by carcinoma cells. Our findings indicate that fibroblasts within invasive breast carcinomas contribute to tumor promotion in large part through the secretion of SDF-1.     

Modification of cellulosic fabric using polyvinyl alcohol, part-II: Colorfastness properties

A series of aqueous solutions of poly(vinyl alcohol) of various commercial products were prepared and applied onto the surfaces of cotton and blends of cotton/polyester fabrics. Fourier transform infrared spectrophotometer was used to confirm the molecular structure of the polyvinyl alcohol used. Performance tests such as colorfastness to rubbing (dry and wet) and colorfastness to washing were determined. The controlling variables affecting the performance properties of the finished substrate such as post-treatment with poly(vinyl alcohol) of various commercial trades, concentration and dilutions were studied. Crocking, washing and hue change of the treated dyed and printed fabrics is accompanied by the formation of semi-inter-penetrated network structure due to the presence of the hydroxyl (-OH) groups which make feasible to a number of grafting and physical cross linking reactions of polymer backbone.