Antioxidant Activities of Photoinduced Phycogenic Silver Nanoparticles and Their Potential Applications.

While various methods exist for synthesizing silver nanoparticles (AgNPs), green synthesis has emerged as a promising approach due to its affordability, sustainability, and suitability for biomedical purposes. However, green synthesis is time-consuming, necessitating the development of efficient and cost-effective techniques to minimize reaction time. Consequently, researchers have turned their attention to photo-driven processes. In this study, we present the photoinduced bioreduction of silver nitrate (AgNO3) to AgNPs using an aqueous extract of Ulva lactuca, an edible green seaweed. The phytochemicals found in the seaweed functioned as both reducing and capping agents, while light served as a catalyst for biosynthesis. We explored the effects of different light intensities and wavelengths, the initial pH of the reaction mixture, and the exposure time on the biosynthesis of AgNPs. Confirmation of AgNP formation was achieved through the observation of a surface plasmon resonance band at 428 nm using an ultraviolet-visible (UV-vis) spectrophotometer. Fourier transform infrared spectroscopy (FTIR) revealed the presence of algae-derived phytochemicals bound to the outer surface of the synthesized AgNPs. Additionally, high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) images demonstrated that the NPs possessed a nearly spherical shape, ranging in size from 5 nm to 40 nm. The crystalline nature of the NPs was confirmed by selected area electron diffraction (SAED) and X-ray diffraction (XRD), with Bragg's diffraction pattern revealing peaks at 2θ = 38°, 44°, 64°, and 77°, corresponding to the planes of silver 111, 200, 220, and 311 in the face-centered cubic crystal lattice of metallic silver. Energy-dispersive X-ray spectroscopy (EDX) results exhibited a prominent peak at 3 keV, indicating an Ag elemental configuration. The highly negative zeta potential values provided further confirmation of the stability of AgNPs. Moreover, the reduction kinetics observed via UV-vis spectrophotometry demonstrated superior photocatalytic activity in the degradation of hazardous pollutant dyes, such as rhodamine B, methylene orange, Congo red, acridine orange, and Coomassie brilliant blue G-250. Consequently, our biosynthesized AgNPs hold great potential for various biomedical redox reaction applications.

Ginsenoside Rg5 Sensitizes Paclitaxel-Resistant Human Cervical-Adeno-Carcinoma Cells to Paclitaxel-And Enhances the Anticancer Effect of Paclitaxel.

In cervical cancer chemotherapy, paclitaxel (PTX) chemoresistance has become a major difficulty, and it also affects the survival rate of numerous tumor patients. Thus, for the reversal of chemoresistance, it is imperative to develop combinatory drugs with petite or almost no side effects to sensitize cells to paclitaxel. Ginsenoside Rg5 (GRg5) may act as a chemosensitizer by reversing multidrug resistance. The present study aimed to determine the potential of GRg5 as a chemosensitizer in PTX-resistant human cervical adeno-carcinoma cell lines (HeLa cells). MTT assay was carried out to assess whether GRg5 can potentiate the cytotoxic effect of PTX in PTX- resistant HeLa cells; using flow cytometry-based annexin V-FITC assay, cellular apoptosis was analyzed; the rate of expression of the cell cycle, apoptosis and major cell-survival-signaling-related genes and its proteins were examined using RT-PCR and Western blotting technique. We found increased mRNA expression of Bak, Bax, Bid, and PUMA genes, whereas the mRNA expression of Bcl2, Bcl-XL, c-IAP-1, and MCL-1 were low; GRg5 combination triggered the efficacy of paclitaxel, which led to increased expression of Bax with an enhanced caspase-9/-3 activation, and apoptosis. Moreover, the study supports GRg5 as an inhibitor of two key signaling proteins, Akt and NF-κB, by which GRg5 augments the susceptibility of cervical cancer cells to PTX chemotherapy. GRg5 drastically potentiated the antiproliferative and pro-apoptotic activity of paclitaxel in PTX-resistant human cervical cancer cells in a synergistic mode. Moreover, in the clinical context, combining paclitaxel with GRg5 may prove to be a new approach for enhancing the efficacy of the paclitaxel.

Increased IL-6 expression precedes reliable viral detection in the rhesus macaque brain during acute SIV infection.

Knowledge of immune activation in the brain during acute HIV infection is crucial for the prevention and treatment of HIV-associated neurological disorders. We determined regional brain (basal ganglia, thalamus, and frontal cortex) immune and virological profiles at 7 and 14 days post infection (dpi) with SIVmac239 in rhesus macaques. The basal ganglia and thalamus had detectable viruses earlier (7 dpi) than the frontal cortex (14 dpi) and contained higher quantities of viruses than the latter. Increased immune activation of astrocytes and significant infiltration of macrophages in the thalamus at 14 dpi coincided with elevated plasma viral load, and SIV colocalized only within macrophages. RNA signatures of proinflammatory responses, including IL-6, were detected at 7 dpi in microglia and interestingly, preceded reliable detection of virus in tissues and were maintained in the chronically infected macaques. Countering the proinflammatory response, the antiinflammatory response was not detected until increased TGF-ß expression was found in perivascular macrophages at 14 dpi. But this response was not detected in chronic infection. Our data provide evidence that the interplay of acute proinflammatory and antiinflammatory responses in the brain likely contributed to the overt neuroinflammation, where the immune activation preceded reliable viral detection.

Improvement of Saccharification and Delignification Efficiency of Trichoderma reesei Rut-C30 by Genetic Bioengineering.

Trichoderma reesei produces various saccharification enzymes required for biomass degradation. However, the lack of an effective lignin-degrading enzyme system reduces the species' efficiency in producing fermentable sugars and increases the pre-treatment costs for biofuel production. In this study, we heterologously expressed the Ganoderma lucidum RMK1 versatile peroxidase gene (vp1) in the Rut-C30 strain of T. reesei. The expression of purified 6×His-tag-containing recombinant G. lucidum-derived protein (rVP1) was confirmed through western blot, which exhibited a single band with a relative molecular weight of 39 kDa. In saccharification and delignification studies using rice straw, the transformant (tVP7, T. reesei Rut-C30 expressing G. lucidum-derived rVP1) showed significant improvement in the yield of total reducing sugar and delignification, compared with that of the parent T. reesei Rut-C30 strain. Scanning electron microscopy (SEM) of tVP7-treated paddy straw showed extensive degradation of several layers of its surface compared with the parent strain due to the presence of G. lucidum-derived rVP1. Our results suggest that the expression of ligninolytic enzymes in cellulase hyperproducing systems helps to integrate the pre-treatment and saccharification steps that may ultimately reduce the costs of bioethanol production.