Adherence of Salmonella typhimurium to murine peritoneal macrophages

Salmonella species are responsible for wide spread disease in both humans, and animals and macrophages (MO play a central role in host defenses against disease. Recent evidence has shown that MO bear surface receptors involved in direct microbial recognition. Using the mouse model and a virulent strain of S. typhimurium, we have attempted to determine the means by which peritoneal MO recognize this pathogen in the absence of serum factors. Bacterial adherence was monitored by direct microscopic visualization and by flow cytometry. Two strains of S. typhimurium strains 1826 and ATCC 14028 were used in this model. Adherence was much lower for strain 1826. Homologous wildtype lipopolysaccharide and, to lesser extent, Re glycolipid and the core sugar 2-keto-deoxyoctonate (KDO) effectively blocked bacterial binding. Two-deoxyglucose, known to inhibit phagocytosis via complement receptors (CR) or Fc receptors, and neutrophil elastase, which specifically cleaves CR1, each reduced binding. Monoclonal antibodies directed against the $\alpha$ and $\beta$ chains of CR3 also reduced binding. Residual bacterial binding activity remained even when both CR1 and CR3 were blocked. We suggest that the initial recognition is a multifactorial process involving ligands on the bacterial LPS and both CR1 and CR3 plus other as yet unidentified MO structures. The role of other receptors on MO was also examined. Antibody to C1q receptor enhanced binding of Salmonella to MO while antibodies to the Mac-2 and Mac-3 receptors had no effect. Using electrophoresis and Western blot techniques, we were able to isolate two MO membrane-proteins each with molecular weight of 16 and 13 kilodaltons. The proteins were identified by labeled bacteria cells. Similarly, we have identified S. typhimurium outer membrane protein that binds to macrophage. The protein has a molecular mass of 44 kilodaltons and is expressed under anaerobic conditions

Antibiotic resistant bacteria in terrestrial and aquatic environments: A review

Antibiotic resistant bacteria have become increasingly widespread in environment and their prevalence is a serious problem for health. The rise and spread of this resistance is primarily due to overuse of antibiotics in clinical therapeutics and as growth promoters for livestock. Overuse undermines the usefulness of antibiotics by giving a selective advantage to microbes that are resistant. The problem has been exacerbated by the emergence of bacteria that are resistant to multiple antibiotics, and by the ability of these resistance determinants to spread horizontally between different bacteria via horizontal gene transfer. Such transfer can, for example, take place in the guts of farm animals, which can become reservoirs of multiple antibiotic resistant bacteria (MARB). Antibiotics and MARB enter the environment via wastewater, especially from hospitals and pharmaceutical plants, and through agricultural runoff, leading to contamination of surface and ground water. This is a serious problem in arid regions such as Oman where wastewater is recycled for irrigation and recharging aquifers. Even treatment with chlorine does not completely remove bacteria from wastewater or prevent their re-growth in downstream distribution systems. MARB can reach humans via contaminated food and drinking water, or directly from the environment. Agricultural runoff and sewage, either treated or untreated, are also the main sources of antibiotic resistant bacteria in coastal sea water. It is necessary to use antibiotics more prudently in medicine, treat wastewater more effectively, eliminate the discharge of untreated waste into the environment, and curtail the profligate use of antibiotics as growth promoters for livestock.Â

Startegi Peningkatan Prestasi Belajar Siswa SD X di Salatiga Ditinjau dari Motivasi Belajar dan Kedisiplinan

Pendidikan formal dimulai dari tahap sekolah dasar dimana seorang anak mendapatkan semua informasi yang dialami dalam kehidupan sehari-hari. Luas wilayah Indonesia yang sangat luas menjadi salah satu faktor kurangnya kemerataan kualitas, mutu dan sumberdaya yang ada. Kualitas pendiidkan dapat dilihat dari hasil belajar siswa. Salah satu faktor yang mempengaruhi hasil belajar adalah motivasi belajar dan kedisiplinan. Kedua hal tersebut memiliki keterkaitan satu sama lain terhasap hasil belajar. Oleh karena itu, dilakukan sebuah penelitian tentang apa strategi yang dilakukan untuk meningkatkan prestasi belajar siswa SD X di Salatiga ditinjau dari motivasi belajar dan kedisiplinan. Untuk mendapatkan jawaban dari pertanyaan di atas maka dilakukan sebuah penelitian dengan teknik pengumpulan data berupa wawancara dan pengambilan nilai sebagai hasil belajar siswa. Setelah data dianalisis dapat diketahui bahwa data tersebut normal sehingga dilakukan tindak lanjut dengan medan ggunakan uji normalitas data menggunakan metode stepwise. Uji tersebut menghasilkan faktor yang paling mempengaruhi hasil belajar siswa adalah disiplin. Berdasarkan hasil analisis yang dilakukan, maka perlu dilakukan treatment khusus pada disiplin siswa sehingga dapat berpengaruh juga pada hasil belajar

Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review

Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers

Adherence of Salmonella typhimurium to Murine Peritoneal Macrophages Is Mediated by Lipopolysaccharide and Complement Receptors

Adherence of Salmonella typhimurium to mouse peritoneal macrophages (Mø) was monitored using a direct microscopic assay and flow cytometry. Competitive binding studies using wild-type lipopolysaccharide and derivatives confirmed a role for this moiety in bacterial adherence. Mø pretreated with 2-deoxy-D-glucose exhibited lower binding activity than did untreated controls, suggesting involvement of either Fc or complement receptors. Pre-exposing Mø to Fc fragments, however, failed to reduce bacterial binding, thus eliminating a role for Fc receptors in this process. Mø pretreated with neutrophil elastase exhibited a diminished ability to bind S. typhimurium, suggesting involvement of complement receptor 1. Monoclonal antibodies M1/70 and M18/2, specific for epitopes on the α and β chains, respectively, of complement receptor 3, also blocked this adherence. In each case we were unable to eliminate completely bacterial adhesion to Mø. Monoclonal antibodies to two additional Mø receptors, Mac-2 and Mac-3, did not block bacterial attachment. These data indicate that multiple mechanisms are involved in the initial adhesion of S. typhimurium to mouse Mø

Synthesis of Pullulan-Mediated Silver Nanoparticles (AgNPs) and their Antimicrobial Activities

The synthesis of silver nanoparticles (AgNPs), using plant extracts, bacteria, fungi and yeasts, and their   antimicrobial activities have been widely investigated and well documented. However, pullulan AgNPs and their antimicrobial activities have not received much attention. The objective of this study was to synthesize pullulan AgNPs, characterize them, and test their antibacterial and antifungal activities. Pullulan was extracted from Aureobasidium mangrovei isolated from Oman and, using UV-Vis spectroscopy and Fourier Transform Infrared (FT-IR), found to be identical to the commercial pullulan obtained from Sigma, USA. Transmission electron microscopy (TEM) showed that most of the synthesized particles were poly-dispersed, irregular in shape, and most were spherical with an average size of 9.76 nm. Pullulan-mediated AgNPs were found to have antibacterial activities, and the ANOVA test showed that there were no significant differences between AgNO3, Pullulan and pullulan-mediated AgNPs for all the bacteria tested. Pullulan-mediated nanoparticles were found to have antifungal activity against Curvularia lunata, Fusarium incarnatum, Aspergillus niger, Aspergillus flavus, Aspergillus ochraceus and Penicillium sp. The ANOVA test also revealed that there was a significant difference in antifungal activity between pullulan and pullulan-mediated AgNPs, pullulan-mediated nanoparticles having shown a higher inhibitory activity than pullulan. Pullulan and pullulan-mediated nanoparticles could be used in the food industry and are safer than silver nitrates

Survival and Growth of Bacteria in Treated Wastewater and Water Distribution Systems and their Implication in Human Health: A review

Multiple antibiotic resistant bacteria (MARB) and antimicrobial drugs enter the environment via wastewater, especially from hospitals and pharmaceutical plants, and through agricultural runoff, leading to contamination of surface and groundwater. This is a serious problem in arid regions such as Oman where wastewater is recycled for irrigation and recharging aquifers. Treatment with chlorine does not completely remove bacteria from wastewater or prevent their re-growth in downstream distribution systems. MARB can infect humans via contaminated food and drinking water, or directly from the environment. Agricultural runoff and sewage, either treated or untreated, are also the main sources of MARB in coastal seawater. It is necessary to use antibiotics more prudently in medicine, treat wastewater more effectively, eliminate the discharge of untreated waste into the environment, and curtail the proflgate use of antibiotics as growth promoters for livestock

Isolation and characterization of cellulolytic Bacillus licheniformis from compost

Eight cellulose degrading bacteria were isolated from compost and were identified as Bacillus licheniformis by 16S rRNA sequencing. Among the eight isolates, Bacillus licheniformis B4, B7 and B8 showed the highest cellulase activity. B. licheniformis B4 and B8 showed the maximum cellulase activity during the stationary phase of growth; but for B7, the maximum activity of cellulase was observed during the log phase. Reducing sugar released in the media, increased with increasing cellulase activity for all the three isolates. Significant correlation was observed between cellulase activity and protein content. The crude cellulase from B7 strain showed activity towards carboxymethyl cellulose and filter paper, but there was no detectable activity towards p-nitrophenyl- β-Dglucopyranoside (PNPG). The crude cellulase of B. licheniformis B7 exhibited maximum activity at 50°C and at pH 6 to 7.Keywords: Bacillus licheniformis, 16S rRNA, cellulase, reducing sugar, compost, viscosit

Analysis of Bacterial Diversity in Different Heavy Oil Wells of a Reservoir in South Oman with Alkaline pH

The identification of potential hydrocarbon utilizing bacteria is an essential requirement in microbial enhanced oil recovery (MEOR). Molecular approaches like proteomic and genomic characterization of the isolates are replacing the traditional method of identification with systemic classification. Genotypic profiling of the isolates includes fingerprint or pattern-based technique and sequence-based technique. Understanding community structure and dynamics is essential for studying diversity profiles and is challenging in the case of microbial analysis. The present study aims to understand the bacterial community composition from different heavy oil contaminated soil samples collected from geographically related oil well areas in Oman and to identify spore-forming hydrocarbon utilizing cultivable bacteria. V4 region of 16S rDNA gene was the target for Ion PGM™. A total of 825081 raw sequences were obtained from Ion torrent from all the 10 soil samples. The species richness and evenness were found to be moderate in all the samples with four main phyla, Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, the most abundant being Firmicutes. Bacillus sp. ubiquitously dominated in all samples followed by Paenibacillus, which was followed by Brevibacillus, Planococcus, and Flavobacterium. Principal Coordinate Analysis (PCoA) and UPGMA dendrogram clustered the 10 soil samples into four main groups. Weighted UniFrac significance test determined that there was significant difference in the communities present in soil samples examined. It can be concluded that the microbial community was different in all the 10 soil samples with Bacillus and Paenibacillus sp. as predominating genus. The 16S rDNA sequencing of cultivable spore-forming bacteria identified the hydrocarbon utilizing bacteria as Bacillus and Paenibacillus sp. and the nucleotide sequences were submitted to NCBI GenBank under accession numbers KP119097–KP119115. Bacillus and Paenibacillus sp., which were relatively abundant in the oil fields, can be recommended to be chosen as candidates for hydrocarbon utilization study