| 1 |
Author(s):
Onwuka Kalu Chima Okpo, Ejike Felix Chukwurah (Prof.).
Page No : 1-11
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G-Protein and G-Protein Coupled Receptors: Implications in Regulation of Immune Response
Abstract
The guanine nucleotide binding proteins (G proteins) act as molecular switches of ‘on’ and ‘off’ when bound to GTP and GDP respectively while the guanine protein coupled receptors (GPCRs) are membrane bound receptors whereby extracellular substances (ligands)communicate signals from these substances to an intracellular molecule the G-proteins which in turn bind and activate or inhibit downstream effect or molecules causing cellular responses. This review is aimed at exploring the concept and mechanism of G-proteins and GPCR and their implication in immune response. The GPCR can be activated by various physiological or pathological processes cellular metabolism, hormones, neuro-transmitters, chemokines, autocrines, paracrines, endocrine and exocrine secretions which play an important role in relaying or routing signals to several intracellular pathways. The signal transduction by the extracellular activation or inhibition of the GPCR mediate metabolic enzymes, ion channels, transporters, cellular gene transcription, migration, survival, activation, differentiation and cytokine secretion of immune cells resulting in the synthesis and regulation of embryonic development, gonadal development, learning /memory organismal homeostasis, hematopoiesis and immune dynamics. Therefore, G proteins and GPCRs signaling systems are key determinants in innate and adaptive immunity. The signal transduction of G-Protein and GPCR by cytokine chemotaxis as Chronic inflammatory mediators is associated with tumorigenesis, metastasis with potential antagonism for appropriate targeted therapy.
| 2 |
Author(s):
Juliana Okwena Pondei, Cynthia Chidimma Okeke.
Page No : 12-22
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Bacterial Isolates of Soils of Different Waste Types in Yenagoa Central Solid Waste Dumpsite, Nigeria.
Abstract
Managing wastes has remained a continuous issue for developing countries like Nigeria. Microorganisms can be utilized to augment the efficiency of degradation of undesired wastes. The microorganisms associated with soils of solid wastes in Yenagoa Central Waste Dumpsite of Bayelsa State, Nigeria were investigated. Soil samples were collected from four locations having sorted wastes of plastics, metals, glass, general wastes and a control area devoid of any waste within the dumpsite. The soil samples were examined for some physicochemical parameters and culturable bacteria using standard procedures. Soil temperature across the locations was 29°C, pH values were between 7.3 and 7.7, moisture contents ranged from 1% – 9%, soil particle sizes were 63.3g/cm – 91.4g/cm, electrical conductivity 62 mS/m – 200 mS/m, and the total organic carbon ranged from 0.88% to 5.64%. The Total Heterotrophic Bacterial (THB) counts were between 1.50 ± 0.00 x 105 cfu/g and 7.96 ± 3.21 x 105 cfu/g, with general wastes having the highest counts and the control soil with the least counts. The frequencies of occurrence of the isolates were Bacillus spp. (21.88%), E. coli (18.75%), Salmonella spp. and Vibrio spp. (15.62%), filamentous bacteria Streptomyces spp. (12.50%) and Eikelboom Type 0092 (9.38%), and Streptococcus spp. (6.25%). All bacterial species were present in the general wastes. Salmonella and Streptococcus species were absent in plastic wastes, Eikelboom type 0092, Vibrio and E. coli were absent in metal wastes while for glass, Eikelboom type 0092, Vibrio and Streptococcus species were not isolated. The control soil was devoid of Streptomyces and Salmonella species. The presence of specific bacterial species with location could be indicative of their association with the biodegradation of the specific waste type. On further research, these microorganisms could be explored for their potential in waste management.
| 3 |
Author(s):
Juliana Okwena Pondei.
Page No : 23-33
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Antibacterial Activity of Endophytic Fungi Isolated from Medicinal Plants: Ocimum Gratissimum and Jatropha Tanjorensis.
Abstract
Endophytes are gaining worldwide recognition because of their potential use in biotechnology and as sources of novel bioactive compounds. A total of 27 fungal endophytes were isolated from the root, stem and leaves of two medicinal plants; Ocimum gratissimum (13) and Jatropha tanjorensis (14). Occurrence of endophyte species of the plants were Alternaria alternata and Aspergillus flavus (22.22% each), Nigrosa oryzae and Penicillium chryseogenum (14.81% each) and Penicillium oxalicum (11.11%). Cladosporium sphaerospernum (7.41%) was isolated from Ocimum gratissimum only and Rhizoctonia solani (7.41%) from Jatropha tanjorensis only. More endophytes were present in the roots and leaves than stems of the plants. Antibacterial screening of 10mg/ml of fungal extracts on five test organisms (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae), using the Agar Well Diffusion Method showed Alternaria alternata with inhibitory zones 20.5 ± 0.15mm – 32.7 ± 0.58mm; Penicillium chryseogenum (14.5 ± 0.20mm – 28.79± 0.26mm); Aspergillus flavus (18.7 ± 0.10mm – 24.7 ± 0.10mm) and Nigrosa oryzae (18.6 ± 0.15mm – 24.7 ± 0.06mm each), with their highest antibacterial activity on Staphylococcus aureus. Cladosporium sphaerospernum (20.9 ± 0.20mm – 30.0 ± 0.06mm) and Penicillium oxalicum (11.3 ± 0.01mm – 22.8 ± 0.15mm) were most inhibitory to Bacillus cereus. Rhizoctonia solani had the least zones of inhibition (8.20 ± 0.20mm – 14.7 ± 0.06mm) and most inhibitory to E. coli and Pseudomonas aeruginosa. The antibacterial activities of the extracts were comparable to that of the standard drug, chloramphenicol (28.4 ± 0.40mm – 36.0 ± 0.12mm). With further research and standardization, these extracts could serve as alternatives to synthesized antibiotics.
Keywords: Antibacterial activity, endophytic fungi, Jatropha tanjorensis, Ocimum gratissimum
