Study of the Adsorption of Human Hemoglobin to Silver (Ag) Nanoparticle Surface for the Detection of the Unfolding of Hemoglobin

In the present report, we focused on the detail study of the optical properties and structural characterization of the Ag NPs for the nanobioconjugate analysis and detection of the conformational structural change of the Hb. The detail optical and structural analysis of Ag NPs has been studied from UV–Vis absorption, emission spectrum, XRD, and HRTEM study. The proteins/Hb are attached immediately onto Ag NPs surface when NPs touch the biological fluids, forming protein corona (PC), which gives their biological identity. The NPs-PC bioconjugate is, more specifically, the true identity of NPs in the physiological world. The adsorption of Hb with Ag NP surfaces has been studied by monitoring the soret band and tryptophan band of Hb. The dynamics of the Hb adsorption on the Ag NPs showed the time constant of surface binding t₁?=?5.79 min and 10.23 min and surface reorganization t₂?=?500 min and 251.75 min with the use of small and large concentrations of Ag NPs, respectively. The absorption peak shape and size around the wavelength, λ ≈ 406.2 nm of the bioconjugate has been examined by Gaussian and Lorentz curve fitting analysis. The bioconjugate along with the PC formation has been analyzed by HRTEM images and DLS observations. The tertiary deformation of Hb and energy transfer efficiency connecting Ag NPs and Hb are discussed from the emission-quenching phenomenon. The change of the secondary structural elements (α-helix, β-sheets, intermolecular aggregates, intramolecular aggregates) of the bioconjugate has been analyzed from FTIR spectrum.

     

Synthesis of HPMC stabilized nickel nanoparticles and investigation of their magnetic and catalytic properties

Nickel nanoparticles synthesized from NiCl₂·6H₂O by hydrazine hydrate in mixed solvent of ethanol and water in the presence of hydroxypropylmethylcellulose (HPMC) as protective and stabilizing agents. The morphology and sizes of synthesized Ni nanoparticles were studied by field-emission-scanning-electron microscopy (FESEM). Structural properties of nanoparticles were examined by X-ray diffraction (XRD). The polymer stabilized Ni nanoparticles were characterized by Fourier-transform infrared (FTIR) spectroscopy. The magnetic measurement showed that the resultant Ni nanoparticles were ferromagnetic. Also, the saturation magnetization (M_S), remanent magnetization (M_R) and coercivity (M_R) were observed to increase with decreasing temperature. The results of magnetic characterization showed that the magnetic properties of the HPMC stabilized Ni nanoparticles are quite different from those of the bared Ni nanoparticles. All the observed magnetic properties essentially reflected the very typical nanoparticle type nature. Consequently, the resulting Ni nanoparticles were found to be highly active and recyclable catalyst for Suzuki coupling reactions.     

In Vitro Assessment of Probiotic Potential of an Autochthonous Bacterial Isolate,Pseudomonas mosselii COFCAU_PMP5

Microbiology - Microbiota of the fish gut contains many beneficial bacteria that can be used as probiotics in aquaculture. In this study, several in vitro assays along with an in vivo safety...     

Effects of exogenous abscisic acid on some physiological responses in a popular aromatic indica rice compared with those from two traditional non-aromatic indica rice cultivars

The poor productivity and local confinement of indigenous aromatic rice varieties are mostly due to their susceptibility to salinity/drought/abscisic acid (ABA)-mediated abiotic stresses. It is thus essential to study the effects of several stress factors on their physiological parameters so as to improve their tolerance mechanism and enhance their global demand. Previously, we studied the effect of salinity stress on the physiological and molecular responses of the common aromatic rice Gobindobhog. The objective of this study was to understand the influence of exogenous ABA on some biochemical parameters in Gobindobhog, and comparison with those from non-aromatic M-1-48 and Nonabokra rice. The highest endogenous hydrogen peroxide content and membrane lipid peroxidation (increased malondialdehyde and lipoxygenase activity) were found in ABA-treated Gobindobhog leaves. While the catalase activity was down regulated the most in ABA-treated Gobindobhog leaves, the guaiacol peroxidase activity was induced maximally, indicating the protective role of peroxidase rather than catalase, during ABA-induced oxidative damages. The antioxidant, anthocyanin, showed the highest level in ABA-treated Nonabokra. Enhanced cysteine, following ABA exposure and the highest levels of reducing sugars, total amino acids, proline, and polyamines (putrescine and spermidine) recorded in Gobindobhog, probably served to shield from ABA-induced stress injuries, whereas the spermine levels were comparable in ABA-treated Nonabokra and Gobindobhog. The aroma content, intensified after ABA treatment, was markedly noted in Gobindobhog. Thus, the systematic examination of ABA-mediated stress revealed the most prominent oxidative damages in Gobindobhog, even higher than M-1-48, with a concomitant enhancement in peroxidase system and particularly osmolyte or polyamine levels to ensure its sustenance.     

Noncytotoxic orange and red/green derivatives of DsRed-Express2 for whole-cell labeling

Background  

Whole-cell labeling is a common application of fluorescent proteins (FPs), but many red and orange FPs exhibit cytotoxicity that limits their use as whole-cell labels. Recently, a tetrameric red FP called DsRed-Express2 was engineered for enhanced solubility and was shown to be noncytotoxic in bacterial and mammalian cells. Our goal was to create derivatives of this protein with different spectral properties.     

Ethylene dimethane sulfonate (EDS) ablation of Leydig cells in adult rat depletes testosterone resulting in epididymal sperm granuloma: Testosterone replacement prevents granuloma formation

Sperm granuloma may develop in the epididymis following vasectomy or chemical insults. Inflammation due to sperm granuloma causes abdominal and scrotal pain. Prolonged and persistent inflammation in the epididymis due to sperm granuloma may lead to infertility. Extravasation of germ cells into the interstitium of epididymis following damage of the epididymal epithelium is one of the primary reasons for sperm granuloma-associated pathology. Since testosterone is vital for the maintenance of epididymal epithelium, we investigated the pathology of sperm granuloma and its relationship with testosterone. Adult rats were treated with a Leydig cell-specific toxicant ethylene dimethane sulfonate (EDS) to eliminate testosterone. At 7 days post-EDS, disrupted epididymal epithelium and sperm granuloma were observed in the caput epididymis. Sperm granuloma and caput were collagen-filled indicating fibrosis. Numerous round apoptotic cells were localized inside the caput lumen and dispersed through the sperm granuloma. Tnp1 (round spermatid marker) was significantly higher in the epididymis of the EDS-treated group compared to controls suggesting the apoptotic cells were round spermatids. Increases in CD68⁺ macrophages and T cells (CD4 and CD8) support an inflammatory immune infiltration in post-EDS epididymis. However, testosterone replacement following EDS prevented the sperm granuloma-associated pathology. We suggest that the immune response in the sperm granuloma may be due to the increased numbers of apoptotic round spermatids or other testicular tissue components that may be released, in addition to the regression of epididymal epithelium due to testosterone loss. Thus, testosterone replacement prevents EDS-induced sperm granuloma and ameliorates sperm granuloma-associated pathology.