Application of green silver nanoparticles synthesized from the red seaweeds Halymenia porphyriformis and Solieria robusta against oral pathogenic bacteria by using microscopic technique.

Aqueous extracts of two red seaweeds Halymenia porphyriformis and Solieria robusta were used to synthesize green silver nanoparticles. These biogenic nanoparticles were tested against four strains of oral pathogenic bacteria which cause tooth decay or cavities. Staphylococcus aureus (MT416445), Streptococcus viridans (MT416448), Lactobacillus acidophilus (MT416447) and Lactobacillus brevis (MT416446) were used. Characterization of AgNPs was done by UV-Visible spectroscopy, SEM, XRD and FTIR. XRD analysis revealed the crystalline nature of the particles. The size analysis by XRD of the green AgNPs by H. porphyriformis indicated it had smaller particles, 15.23 nm, when compared to AgNPs by S. robusta (17 nm). Both green synthesized silver nanoparticles showed moderate antibacterial activity against all strains of bacteria, except L. acidophilus. Both particles showed their maximum zone of inhibition against L. acidophilus at a lower concentration of 50 and 100 µg. However, it was concluded that silver nanoparticles of H. porphyriformis are more effective than that of S. robusta due to their smaller size.

The Oral-Gut-Brain AXIS: The Influence of Microbes in Alzheimer's Disease.

Alzheimer's disease (AD) is one of the most frequently diagnosed neurodegenerative disorders worldwide and poses a major challenge for both affected individuals and their caregivers. AD is a progressive neurological disorder associated with high rates of brain atrophy. Despite its durable influence on human health, understanding AD has been complicated by its enigmatic and multifactorial nature. Neurofibrillary tangles and the deposition of amyloid-beta (Aß) protein are typical pathological features and fundamental causes of cognitive impairment in AD patients. Dysbiosis of oral and gut microbiota has been reported to induce and accelerate the formation of Aß plaques and neurofibrillary tangles. For instance, some oral microbes can spread to the brain through cranial nerves or cellular infections, which has been suggested to increase the risk of developing AD. Importantly, the interaction between intestinal microbiota and brain cells has been recognized as influencing the development of AD as well as other neurodegenerative diseases. In particular, the metabolites produced by certain intestinal microorganisms can affect the activity of microglia and further mediate neuroinflammation, which is a leading cause of neuronal necrosis and AD pathogenesis. Which pathogens and associated pathways are involved in the development and progression of AD remains to be elucidated; however, it is well-known that gut microbiota and their metabolites can affect the brain by both direct and indirect means. Understanding the specific mechanisms involved in the interaction between these pathogens and the nervous system is vital for the early intervention in AD. In this review, we aim to comprehensively discuss the possible mechanistic pathways underlying the oral-brain, the gut-brain and the oral-gut-brain associations.

Multienzyme and Antibacterial Potential of Bacteria Isolated from gut of Asian Honey Bee (Apis cerana Indica), Lahore Using Culture Dependent Method

Abstract The bacteria residing in the gut of honey bees (HB) has demonstrated a significant role in protecting bees against various pathogens, production of honey and wax. However, no information exists about the antibacterial potential of bacterial isolates from gut of Asian HB, Apis cerana Indica F. (Hymenoptera: Apidae), against human pathogens. This study aims to investigate the antibacterial and multienzyme potential of aerobic bacteria from A. cerana gut using culture dependent approach. A total of 12 HB gut bacteria were characterized morphologically and biochemically. These strains were further screened for their antimicrobial activity against pathogenic human microorganisms Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Bacillus licheniformis and Bacillus subtilis using cross streak (primary screening) and agar well diffusion methods (secondary screening). Preliminary characterization of cell-free supernatant (CFS) of two promising isolates was performed by measuring lactic acid concentrations, enzymatic digestion of antimicrobial compounds, stability over a range of temperature, pH and amplification of spaS (subtilin) and spoA (subtilosin) genes. In primary screening, among 12 HB isolates, eight strains showed statistically significant highest zones of inhibition (p≤0.05) against E. coli, K. pneumoniae and P. aeruginosa. 16S rRNA sequencing revealed that these isolates belong to Bacillus genus, identified as B. tequilensis, B. pumilus, B. xiamenensis, B. subtilis, B. amyloliquefaciens, B. safensis, B. licheniformis, B. altitudinis (Accession numbers: MT186230-MT186237). Secondary screening revealed that among eight isolates, B. subtilis and B. amyloliquefaciens showed statistically significantly strong inhibition (p≤0.05) against all tested pathogens. Antibiotic susceptibility testing revealed that both isolates were resistant to antibiotics and possesses proteolytic, lipolytic and cellulolytic activities. The nature of the compound causing inhibitory activity was found to be proteinaceous and showed stability over a wide range of temperature as well as pH. PCR study confirmed the presence of bacteriocins by successful amplification of important antimicrobial peptide biosynthesis genes spaS and spoA. These results suggest that the HB gut is a home to bacteria that possess antimicrobial activity and important enzymes with antimicrobial potential. To our knowledge, this is the first report demonstrating the antimicrobial potential of bacteria isolated from gut of HB (A. cerana) against human pathogens.

Antioxidant potential and chemical characterization of bioactive compounds from a medicinal plant Colebrokea oppositifolia Sm.

Colebrookea oppositifolia is a highly used medicinal plant and an enriched source of essential oils. Therefore, the present study was designed with the aim to extract the chemical constituents and to evaluate its antioxidant potential. Fresh plant parts were subjected to the extraction of volatile chemical constituents by maceration using n-hexane as the menstruum. The resulting n-hexane fractions were purified and then subjected to GC-MS and FTIR analysis. In-vitro antioxidant abilities were evaluated by, DPPH, total phenolic content (TPC), total flavonoid content (TFC) method against the standard solutions of (Gallic acid, Quercetin) as a positive control. The GC-MS analysis of leaves, stem and inflorescence showed a total of 100, 98 and 48 components out of which 47, 16 and 17 peaks were identified representing the 67.64 %, 73.16 % and 61.93 % of the total oily fractions, respectively. The FTIR spectrum indicated the presence of various functional groups. In-vitro antioxidant results exhibited that leaves showed the highest antioxidant potential by DPPH (3.365 ± 0.002), and the highest total phenolic content by FC method (203.00 ± 0.091). Foliar micromorphological features were found significant in the authentication of C. oppositifolia. Further pharmacognostic studies of this plant are recommended to evaluate its therapeutic potential.

Damage of neuroblastoma cell SH-SY5Y mediated by MPP+ inhibits proliferation of T-cell leukemia Jurkat by co-culture system.

The adaptive immune system has implications in pathology of Parkinson's disease (PD). Research data demonstrated that the peripheral CD4+ T-cell population decreased in pathogenesis of PD. The effect of damaged dopaminergic neurons on peripheral T cells of PD is still unknown. In this study, we constructed a neuronal and glial cells co-culture model by using human neuroblastoma cells SH-SY5Y and gliomas cells U87. After the co-culture cells were treated with neurotoxin 1-methyl-4-phenylpyridinium (MPP+) for 24 h, the conditioned media was harvested and used to cultivate T-cell leukemia Jurkat cells for another 24 h. We then analyzed the cell proliferation, cell cycle and necrosis effect of Jurkat cells. The results showed that co-culture medium of SH-SY5Y and U87 cells with MPP+ treatment inhibited the proliferation of Jurkat cells compared to control medium without MPP+, even though the same concentration of MPP+ had very little toxicity to the Jurkat cell. Furthermore, co-culture medium with low concentration of MPP+ (100 µM) arrested Jurkat cells cycle in G2/M phase through increasing cell cycle division 2 (CDC2) and CyclinB1 expression level, whereas co-culture medium with high concentration of MPP+ (500 µM) induced Jurkat cell necrosis through cellular swelling and membrane breakage. Our data implies that damaged dopamine neurons with glial cells can lead to the reduced number or inhibited proliferation activity of peripheral T cells.