DNA sequencing with chain terminating inhibitors

The pollution of rivers and lakes is of concern because of the threat to public water supplied and because of the damage caused to natural ecosystems. Waterborne diseases remain rife in the Third World, while in developed countries there has been a decline in the quality of water. It has also become apparent that pollutants may destroy ecosystems hundreds of miles from their source. Some of these toxic materials such as lead and PCBs also pose threats to public health. This text describes the sources of various types of pollutants, their effects on aquatic organisms, ecosystems and man, using case histories where appropriate. Ways of mitigating the effects of pollutants by control and ecosystem manipulation are described. Techniques for assessing the effects of pollution, both in field and laboratory, are introduced. The role of the biologist in pollution assessment and control and in the wider sphere of mangement of acquatic resources is also examined.

Biology of Freshwater Pollution.

Plastic pollution is fueling the grave environmental threats currently facing humans, the animal kingdom, and the planet. The pursuit of renewable resourced biodegradable materials commenced in the 1970s with the need for carbon neutral fully sustainable products driving important progress in recent years. The development of bioplastic materials is highlighted as imperative to the solutions to our global environment challenges and to the restoration of the wellbeing of our planet. Bio-based plastics are becoming increasingly sustainable and are expected to substitute fossil-based plastics. Bioplastics currently include both, nondegradable and biodegradable compositions, depending on factors including the origins of production and post-use management and conditions. Among the most promising materials being developed and evaluated is polyhydroxybutyrate (PHB), a microbial bioprocessed polyester belonging to the polyhydroxyalkanoate (PHA) family. This biocompatible and non-toxic polymer is biosynthesized and accumulated by a number of specialized bacterial strains. The favorable mechanical properties and amenability to biodegradation when exposed to certain active biological environments, earmark PHB as a high potential replacement for petrochemical based polymers such as ubiquitous high density polyethylene (HDPE). To date, high production costs, minimal yields, production technology complexities, and difficulties relating to downstream processing are limiting factors for its progression and expansion in the marketplace. This review examines the chemical, mechanical, thermal, and crystalline characteristics of PHB, as well as various fermentation processing factors which influence the properties of PHB materials.

https://www.mdpi.com/2073-4360/12/12/2908/pdf

Production of Polyhydroxybutyrate (PHB) and Factors Impacting Its Chemical and Mechanical Characteristics.

Bacterial nanocellulose (BNC) has been drawing enormous attention because of its versatile properties. Herein, we shed light on the BNC production by a novel bacterial isolate (MD1) utilizing various agro-industrial wastes. Using 16S rRNA nucleotide sequences, the isolate was identified as Komagataeibacter saccharivorans MD1. For the first time, BNC synthesis by K. saccharivorans MD1 was investigated utilizing wastes of palm date, fig, and sugarcane molasses along with glucose on the Hestrin-Schramm (HS) medium as a control. After incubation for 168 h, the highest BNC yield was perceived on the molasses medium recording 3.9 g/L with an initial concentration of (v/v) 10%. The physicochemical characteristics of the BNC sheets were inspected adopting field-emission scanning electron microscope (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The FESEM characterization revealed no impact of the wastes on either fiber diameter or the branching scheme, whereas the AFM depicted a BNC film with minimal roughness was generated using date wastes. Furthermore, a high crystallinity index was estimated by XRD up to 94% for the date wastes-derived BNC, while the FTIR analyses exhibited very similar profiles for all BNC films. Additionally, mechanical characteristics and water holding capacity of the produced BNCs were studied. Our findings substantiated that expensive substrates could be exchanged by agro-industrial wastes for BNC production conserving its remarkable physical and microstructural properties.

/pdf/bacterial-nanocellulose-from-agro-industrial-wastes-low-cost-4z7ol9lort.pdf

Bacterial nanocellulose from agro-industrial wastes: low-cost and enhanced production by Komagataeibacter saccharivorans MD1

Synthesis, characterization and antimicrobial evaluation of two aromatic chitosan Schiff base derivatives

Substituting petroleum-derived polymers with biodegradable and biocompatible polyhydroxybutyrate (PHB) is a challenge to sustain the environmental system. This study intends to optimize the cultural conditions for PHB production by nonpathogenic Bacillus subtilis isolated from Jatropha field. Various agricultural and industrial wastes such as corn bran, corncob, wheat bran, rice bran, dairy waste, and sugarcane molasses were utilized for PHB production. Among these wastes, rice bran was the best carbon source for PHB production (0.31 g/l) with 30.4% of the dry cell weight (DCW). Cultural parameters influencing PHB production were studied employing Plackett–Burman and Box–Behnken designs. Accordingly, pH, incubation time, and inoculum size were found to be the most influential factors on PHB production. Using optimized conditions, sixfold augment in PHB content (0.81 g/l, 62.6% DCW) was attained using rice bran. PHBs obtained from glucose and rice bran were characterized using 1H NMR, FT-IR, TGA, and DSC analysis. Structures of PHBs were comparable, whereas the findings of thermal studies revealed that rice bran-derived PHB showed higher thermal stability with lower melting temperature than glucose-derived PHB. These results substantiate the potential use of this safe isolate utilizing inexpensive substrates for PHB production that could be adopted in medical applications.

Statistical optimization studies for polyhydroxybutyrate (PHB) production by novel Bacillus subtilis using agricultural and industrial wastes

Synthetic polymers are non-degradable and accumulated in the environment so, the efforts of scientists were forwarded to provide us with alternative environmentally biopolymers. Polyhydroxyalkanoates (PHAs) including polyhydroxybutyrate (PHB) are Group of the interesting biopolymers which have several medical applications such as drug delivery, suture, scaffold and heart valves. PHAs and are biological macromolecules, thermoplastics, biodegradable and biocompatible. In this study, new bacterial isolates from Egypt were screened for their ability to produce PHB using Nile red dye. Out of 44 isolates, 19 bacterial isolates were selected according to strong of their fluorescence on mineral salt medium (MSM) agar plates supplemented with Nile red. The most potent strain was identified using biochemical tests as Bacillus sp. N-2. Production of PHB was carried out in limitation of nitrogen source using minimal salt medium (MSM) supplemented with excess of glucose as sole carbon source. PHB was accumulated in relation with cell dry weight about 20% (PHB/CDW). The obtained biopolymer was purified and analyzed using NMR, FTIR, TGA and DSC thus; it was highly pure and identified as PHB. Optimization of PHB production from cheap sources appears to be a realistic goal in the future for reducing the costs and obtaining high yield.

/pdf/production-and-characterization-of-polyhydroxybutyrate-phb-2wupsaqkik.pdf

Production and characterization of polyhydroxybutyrate (PHB) produced by Bacillus sp. isolated from Egypt

Cinnamomum camphora methanolic extract was tested for antifungal activity against three common, isolated, widespread phytopathogens: Alternaria alternata, Fusarium solani, and Fusarium oxysporum, which were molecularly identified and assigned accession numbers ON795987, ON795988, and ON795989, respectively. At 4000 µg/mL, the highest concentration of C. camphora methanolic extract inhibits the fungal mycelia weight of F. oxysporum, A. alternata, and F. solani by 60, 49, and 24%, respectively. The presence of several bioactive metabolites in the C. camphora extract could explain its antifungal activity. The presence of numerous phenolic and flavonoid compounds in the extract was revealed by HPLC analysis, including catechin and gallic acid, which had the highest concentrations of 6.21 and 6.98 µg/mL, respectively. Furthermore, osmoprotectants, total amino acids, and glycine betaine were abundant. Furthermore, total antioxidant activities, as measured by PMA and DPPH, were significant. The most abundant compound in the extract, according to GC-MS analysis, was mono(2-ethylhexyl) ester of 1,2-benzene dicarboxylic acid. Based on its in vitro efficacy in inhibiting mycelial growth weight, the tested extract could be recommended as a safe fungicide instead of a chemical treatment.

/pdf/phytochemical-characterization-and-antifungal-efficacy-of-3i5h9p2b.pdf

Phytochemical Characterization and Antifungal Efficacy of Camphor (Cinnamomum camphora L.) Extract against Phytopathogenic Fungi

 Abstract— Objective: The present study aimed to investigate antibacterial activity of thyme and rifampicin alone and in combination against 45 Methecillin Resistant Staphylococcus aureus isolates (MRSA). Materials and Methods: The present study deals with determination of minimal inhibitory concentration (MICs), killing curve and synergism assay of thyme extracts and rifampicin for MRSA isolates Results: The result indicate that MICs of thyme aqueous extract mixed with rifampicin for all tested MRSA ranged between 0.2µg/ml of rifampicin plus 1.5mg/ml of thyme aqueous extract and 16µg/ml of rifampicin plus 2mg/ml of thyme aqueous extract, that was compared with MICs of rifampicin thyme methanol extract, MICs of rifampicin and thyme hexane extract combination, rifampicin MIC and thyme different extracts MICs. Time-killing curve of rifampicin in combination with thyme aqueous extract exhibit zero CFU/ml after 10 hrs incubation period at 37oC that was compared with time-killing curve of rifampicin in combination with thyme methanol extract, time-killing curve of rifampicin in combination with thyme hexane extract, time-killing curve of rifampicin and time-killing curve of thyme different extracts. Conclusion: From our data we conclude that,thyme aqueous extract combined with rifampicin is the best combination to be used as anti- staphylococcal agent. Key variables: Rifampicin, Thyme, Staphylococcus aureus, Combination

In vitro antibacterial activities of rifampicin and cinnamon on methicillin resistant staphylococcus aureus (mrsa)

Human SARS-CoV-2 and avian infectious bronchitis virus (IBV) are highly contagious and deadly coronaviruses, causing devastating respiratory diseases in humans and chickens. The lack of effective therapeutics exacerbates the impact of outbreaks associated with SARS-CoV-2 and IBV infections. Thus, novel drugs or therapeutic agents are highly in demand for controlling viral transmission and disease progression. Mesenchymal stem cells (MSC) secreted factors (secretome) are safe and efficient alternatives to stem cells in MSC-based therapies. This study aimed to investigate the antiviral potentials of human Wharton’s jelly MSC secretome (hWJ-MSC-S) against SARS-CoV-2 and IBV infections in vitro and in ovo. The half-maximal inhibitory concentrations (IC50), cytotoxic concentration (CC50), and selective index (SI) values of hWJ-MSC-S were determined using Vero-E6 cells. The virucidal, anti-adsorption, and anti-replication antiviral mechanisms of hWJ-MSC-S were evaluated. The hWJ-MSC-S significantly inhibited infection of SARS-CoV-2 and IBV, without affecting the viability of cells and embryos. Interestingly, hWJ-MSC-S reduced viral infection by >90%, in vitro. The IC50 and SI of hWJ-MSC secretome against SARS-CoV-2 were 166.6 and 235.29 µg/mL, respectively, while for IBV, IC50 and SI were 439.9 and 89.11 µg/mL, respectively. The virucidal and anti-replication antiviral effects of hWJ-MSC-S were very prominent compared to the anti-adsorption effect. In the in ovo model, hWJ-MSC-S reduced IBV titer by >99%. Liquid chromatography-tandem mass spectrometry (LC/MS-MS) analysis of hWJ-MSC-S revealed a significant enrichment of immunomodulatory and antiviral proteins. Collectively, our results not only uncovered the antiviral potency of hWJ-MSC-S against SARS-CoV-2 and IBV, but also described the mechanism by which hWJ-MSC-S inhibits viral infection. These findings indicate that hWJ-MSC-S could be utilized in future pre-clinical and clinical studies to develop effective therapeutic approaches against human COVID-19 and avian IB respiratory diseases.

/pdf/human-whartons-jelly-mesenchymal-stem-cells-secretome-24gpfwh6.pdf

Elsayed K. Bakhiet

Papers

Statistical optimization studies for polyhydroxybutyrate (PHB) production by novel Bacillus subtilis using agricultural and industrial wastes

Production and characterization of polyhydroxybutyrate (PHB) produced by Bacillus sp. isolated from Egypt

Phytochemical Characterization and Antifungal Efficacy of Camphor (Cinnamomum camphora L.) Extract against Phytopathogenic Fungi

In vitro antibacterial activities of rifampicin and cinnamon on methicillin resistant staphylococcus aureus (mrsa)

Human Wharton’s Jelly Mesenchymal Stem Cells Secretome Inhibits Human SARS-CoV-2 and Avian Infectious Bronchitis Coronaviruses