Combination of LC3 shRNA Plasmid Transfection and Genistein Treatment Inhibited Autophagy and Increased Apoptosis in Malignant Neuroblastoma in Cell Culture and Animal Models

Malignant neuroblastoma is an extracranial solid tumor that usually occurs in children. Autophagy, which is a survival mechanism in many solid tumors including malignant neuroblastoma, deters the efficacy of conventional chemotherapeutic agents. To mimic starvation, we used 200 nM rapamycin that induced autophagy in human malignant neuroblastoma SK-N-BE2 and IMR-32 cells in cell culture and animal models. Combination of microtubule associated protein light chain 3 short hairpin RNA (LC3 shRNA) plasmid transfection and genistein (GST) treatment was tested for inhibiting rapamycin-induced autophagy and promoting apoptosis. The best synergistic efficacy caused the highest decrease in cell viability due to combination of 50 nM LC3 shRNA plasmid transfection and 25 µM GST treatment in rapamycin-treated SK-N-BE2 cells while combination of 100 nM LC3 shRNA plasmid transfection and 25 µM GST treatment in rapamycin-treated IMR-32 cells. Quantitation of acidic vesicular organelles confirmed that combination of LC3 shRNA plasmid transfection and GST treatment prevented rapamycin-induced autophagy due to down regulation of autophagy promoting marker molecules (LC3 II, Beclin 1, TLR-4, and Myd88) and upregulation of autophagy inhibiting marker molecules (p62 and mTOR) in both cell lines. Apoptosis assays showed that combination therapy most effectively activated mitochondrial pathway of apoptosis in human malignant neuroblastoma in cell culture and animal models. Collectively, our current combination of LC3 shRNA plasmid transfection and GST treatment could serve as a promising therapeutic strategy for inhibiting autophagy and increasing apoptosis in human malignant neuroblastoma in cell culture and animal models.     

Genomic annotation and validation of bacterial consortium NDMC-1 for enhanced degradation of sugarcane bagasse

This study aims at designing a consortium using rumen bacterial isolates for enhancing the hydrolysis of sugarcane bagasse (SB) for efficient biofuel formation. The microbial population was screened through biochemical and molecular tools along with enzymatic activity to obtain potential isolates for diverse cellulolytic and hemicellulolytic carbohydrate active enzyme (CAZyme). Five strains (Paenibacillus, Bacillus, Enterobacter, and Microbacterium) were selected for designing the consortium NDMC-1. The hydrolytic efficiency of NDMC-1 was determined based on cellulase production with simultaneous rise in monosaccharides, oligosaccharides, and soluble chemical oxygen demand (sCOD) concentration. Cellulolytic machinery of these isolates was further explored using genome sequencing. The isolates selected for consortia NDMC-1 interacted synergistically leading to enhanced cellulase production. Maximal endoglucanase (1.67 μmol ml−1 min−1), exoglucanase (0.69 μmol ml−1 min−1), and β-glucosidase (2.03 μmol ml−1 min−1) activity were achieved with SB as a sole carbon source after 48 h of incubation. Enhancement in SB hydrolysis employing NDMC-1 was evident by the increase in sCOD from 609 to 2589 mg/l and release of 1295 mg/l reducing sugar, comprising 59.8%, 8.23%, and 6.16% of glucose, cellobiose, and cellotriose, respectively, which resulted in 5.5-fold rise in biogas production. On genome annotation, total 472 contigs from glycoside hydrolase family: 84 from Microbacterium arborescens ND21, 72 from Enterobacter cloacae ND22, 61 from Bacillus subtilis ND23, 116 from Paenibacillus polymyxa ND24, and 140 from Paenibacillus polymyxa ND25 were identified. On further analysis, total 33 cellulases, 59 hemicellulases, and 48 esterases were annotated in the reported genomes. This work proposes the application of consortia-based bioprocessing systems over the conventionally favorable single organism approach for efficient hydrolysis of cellulosic substrates to fermentable sugars.     

Decolorization of diazo dye Direct Red 81 by a novel bacterial consortium

Summary Samples collected from various effluent-contaminated soils in the vicinities of dyestuff manufacturing units of Ahmedabad, India, were studied for screening and isolation of organisms capable of decolorizing textile dyes. A novel bacterial consortium was selected on the basis of rapid decolorization of Direct Red 81 (DR 81), which was used as model dye. The bacterial consortium exhibited 90% decolorization ability within 35 h. Maximum rate of decolorization was observed when starch (0.6 g l⁻¹) and casein (0.9 g l⁻¹) were supplemented in the medium. Decolorization of DR 81 was monitored by high performance thin layer chromatography, which indicated that dye decolorization was due to its degradation into unidentified intermediates. The optimum dye-decolorizing activity of the culture was observed at pH 7.0 and incubation temperature of 37 °C. Maximum dye-decolorizing efficiency was observed at 200 mg l⁻¹ concentration of DR 81. The bacterial consortium had an ability to decolorize nine other structurally different azo dyes.     

Correction to: A review on the genus Populus: a potential source of biologically active compounds

Phytochemistry Reviews -     

Bacterial Virulence Factors: Secreted for Survival

Virulence is described as an ability of an organism to infect the host and cause a disease. Virulence factors are the molecules that assist the bacterium colonize the host at the cellular level. These factors are either secretory, membrane associated or cytosolic in nature. The cytosolic factors facilitate the bacterium to undergo quick adaptive—metabolic, physiological and morphological shifts. The membrane associated virulence factors aid the bacterium in adhesion and evasion of the host cell. The secretory factors are important components of bacterial armoury which help the bacterium wade through the innate and adaptive immune response mounted within the host. In extracellular pathogens, the secretory virulence factors act synergistically to kill the host cells. In this review, we revisit the role of some of the secreted virulence factors of two human pathogens: Mycobacterium tuberculosis—an intracellular pathogen and Bacillus anthracis—an extracellular pathogen. The advances in research on the role of secretory factors of these pathogens during infection are discussed.     

Effect of trehalose on protein structure

Trehalose is a ubiquitous molecule that occurs in lower and higher life forms but not in mammals. Till about 40 years ago, trehalose was visualized as a storage molecule, aiding the release of glucose for carrying out cellular functions. This perception has now changed dramatically. The role of trehalose has expanded, and this molecule has now been implicated in a variety of situations. Trehalose is synthesized as a stress‐responsive factor when cells are exposed to environmental stresses like heat, cold, oxidation, desiccation, and so forth. When unicellular organisms are exposed to stress, they adapt by synthesizing huge amounts of trehalose, which helps them in retaining cellular integrity. This is thought to occur by prevention of denaturation of proteins by trehalose, which would otherwise degrade under stress. This explanation may be rational, since recently, trehalose has been shown to slow down the rate of polyglutamine‐mediated protein aggregation and the resultant pathogenesis by stabilizing an aggregation‐prone model protein. In recent years, trehalose has also proved useful in the cryopreservation of sperm and stem cells and in the development of a highly reliable organ preservation solution. This review aims to highlight the changing perception of the role of trehalose over the last 10 years and to propose common mechanisms that may be involved in all the myriad ways in which trehalose stabilizes protein structures. These will take into account the structure of trehalose molecule and its interactions with its environment, and the explanations will focus on the role of trehalose in preventing protein denaturation.