Isolation and characterization of cyclo-(tryptophanyl-prolyl) and chloramphenicol from Streptomyces sp. SUK 25 with antimethicillin-resistant Staphylococcus aureus activity

Background: Zingiber spectabile, commonly known as Beehive Ginger, is used as an ethnobotanical plant in many countries as an appetizer or to treat stomachache, toothache, muscle sprain, and as a cure for swelling, sores and cuts. This is the first report of isolation of Streptomyces strain from the root of this plant. Strain Universiti Kebangsaan 25 (SUK 25) has a very high activity to produce secondary metabolites against methicillin-resistant Staphylococcus aureus (MRSA), which is associated with high morbidity and mortality rates due to acquired multidrug resistance genes and causes medication failure in some clinical cases worldwide. Phylogenetic analysis based on the 16S ribosomal RNA gene sequence exhibited that the most closely related strain was Streptomyces omiyaensis NBRC 13449T (99.0% similarity). Aim: This study was conducted to carry out the extraction, identification, and biological evaluation of active metabolites isolated from SUK 25 against three MRSA strains, namely, MRSA ATCC 43300, MRSA ATCC 33591, and MRSA ATCC 49476. Materials and methods: The production of secondary metabolites by this strain was optimized through Thronton’s media. Isolation, purification, and identification of the bioactive compounds were carried out using reversed-phase high-performance liquid chromatography, high-resolution mass spectrometry, Fourier transform infrared, and one-dimensional and twodimensional nuclear magnetic resonance. Results: During screening procedure, SUK 25 exhibited good antimicrobial potential against several strains of MRSA. The best biological activity was shown from fraction number VII and its subfractions F2 and F3 with minimum inhibitory concentration values at 16 µg/mL and 8 µg/mL, respectively. These two subfractions were identified as diketopiperazine cyclo(tryptophanyl-prolyl) and chloramphenicol. Conclusion: On the basis of obtained results, SUK 25 isolated from Z. spectabile can be regarded as a new valuable source to produce secondary metabolites against bacteria, especially MRSA

Isolation, purification, and characterization of five active diketopiperazine derivatives from endophytic streptomyces SUK 25 with antimicrobial and cytotoxic activities

In our search for new sources of bioactive secondary metabolites from Streptomyces sp., the ethyl acetate extracts from endophytic Streptomyces SUK 25 afforded five active diketopiperazine (DKP) compounds. The aim of this study was to characterize the bioactive compounds isolated from endophytic Streptomyces SUK 25 and evaluate their bioactivity against multiple drug resistance (MDR) bacteria such as Enterococcus raffinosus, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter spp., and their cytotoxic activities against the human hepatoma (HepaRG) cell line. The production of secondary metabolites by this strain was optimized through Thornton's medium. Isolation, purification, and identification of the bioactive compounds were carried out using high-performance liquid chromatography, high-resolution mass liquid chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and nuclear magnetic resonance, and cryopreserved HepaRG cells were selected to test the cytotoxicity. The results showed that endophytic Streptomyces SUK 25 produces four active DKP compounds and an acetamide derivative, which were elucidated as cyclo-(L-Val-L-Pro), cyclo-(L-Leu-L-Pro), cyclo-(L-Phe-L-Pro), cyclo-(L-Val-L-Phe), and N-(7-hydroxy-6-methyl-octyl)-acetamide. These active compounds exhibited activity against methicillin-resistant S. aureus ATCC 43300 and Enterococcus raffinosus, with low toxicity against human hepatoma HepaRG cells. Endophytic Streptomyces SUK 25 has the ability to produce DKP derivatives biologically active against some MDR bacteria with relatively low toxicity against HepaRG cells line

Investigating the relationship between cultural intelligence and service quality in hospitality :A cross cultural study

This study investigates the effect of cultural intelligence of front-line service employees on foreign guests’ perceptions of service quality. This relationship has not hitherto been investigated. The literature suggests that culture and interactions between customers and employees affect service quality. The literature also shows that, in cross-cultural encounters, attitudes and behaviours are important aspects of cultural intelligence, employee performance and service quality. It also points to interrelationships between these constructs. A theoretical model was developed which suggests that in these encounters, cultural intelligence is likely to affect service quality through employee performance. A novel methodological approach consisting of a pilot study and two stages of empirical research were undertaken in international hotels in Karbala, Iraq. The first, qualitative stage was in the form of interviews to gain an insight into the service interactions. Thematic analysis of the data supported the theoretical model and pointed to additional causal relationships. The model was tested in the second quantitative stage. A self-report cultural intelligence questionnaire was administered to a sample of local employees (N=201). A new job performance questionnaire was designed and administered to hotel managers (N=53) to assess these employees’ performance. A SERVPERF questionnaire was also given to foreign guests (N=469) who were served by these employees. The dimensions of these measures were determined by principal components analysis (SPSS 22), and their adequacy was estimated using confirmatory factor analysis (Lisrel 8.8). The model was tested using hierarchical multi-regression analysis. The findings showed that employee performance mediated the relationships between cultural intelligence and service quality. Another main contribution is the development of an employee performance scale for use in service encounters. The study adds to the crosscultural service literature and to research methodology design. Its implications for management and employee training were discussed, as well as its limitations. Further research was also suggested

Evaluation and Exploration of Microbial Quality and Safety Aspects of Unpasteurized Retail Maine Dairy Products

The Dietary Guidelines for Americans recommend dairy products as part of a healthy diet and these products are significant contributors of important nutrients. In the U.S., and Maine specifically, demand for locally-produced, minimally processed foods, including unpasteurized dairy, has increased during the past several decades. An analysis of retrospective microbial testing data for unpasteurized retail dairy products revealed increasing microbial quality from 1998-2016, despite a five-fold increase in sample numbers during this time. Higher percentages of samples were non-compliant with microbial quality standards during the summer months compared to winter. High coliform counts were the leading cause of non-compliant samples in milks and other dairy-based products. The second objective of this research was to investigate the effects of cheesemaking and aging temperature on levels of inoculated foodborne pathogens. The cheesemaking process did not affect the populations of either pathogen of interest. During aging, lower temperatures (4℃ and 10℃) significantly decreased population of Shiga-toxigenic E. coli, whereas only 4℃ significantly reduced L. monocytogenes. Aging at 4℃ was also effective in maintaining the population of the starter culture. The highest aging temperature (22℃) caused a significant increase of both pathogens as well as a significant increase in pH levels and softening of the cheese texture. In tests of unpasteurized retail dairy products, the highest rates of presumptive positive results for Listeria spp. were recorded in July and August. The prevalence of presumptive positive Listeria spp. was higher in mold-ripened compared to soft cheeses. There was a significant positive correlation between non-compliant levels of coliforms and presence of presumptive positive Listeria spp. in the samples tested. The results of this research suggest that the overall quality of the expanding unpasteurized dairy sector in Maine has remained constant or improved in the past two decades. Small-scale cheese operations participating in this market should use refrigeration temperatures for aging of cheese when possible, which will provide the best control against foodborne pathogens. Finally, more targeted testing techniques are suggested to detect the potential sources of coliforms and to ensure the safety of unpasteurized dairy commodities

Implementing Alternative Sentencing in the Criminal Justice System: Implications for Human Rights

Prisons operate with varying aims, including the infliction of punishment, individualdeterrence and general deterrence, even retribution or revenge. One aim is to enable offenders to become aware of their mistakes and be accepted back into the community. A problem with implementing this aim is, however, that imprisonment may generate greater capacity for offending in the convict, who may emerge from prison ‘worse’ than when entering it. This article briefly reviews the philosophy that lies behind alternatives to imprisonment by reference to a small slice of the literature and concludes that more research is required to draw firm conclusions about their efficacy. Research is needed on the domesticlevel and internationally to determine how alternative punishments may result in upholding the human rights of offenders and improving outcomes for society as a whole

Does the Use of Twitter Improve 'Communicative Competence' of Saudi Higher Education Students?

The world has seen the emergence of social media, and it has wider implications for all aspects of human life. This has consequently led to the emergence of research on various aspects of life such as knowledge, well-being and emotions. This research looks at how the frequency, quality and duration of Twitter use affect the English language communicative competence of Saudi higher education students. Communicative competence was estimated across four different measures: Linguistic, Discourse, Strategic and Sociolinguistic competence. Data was collected using self-administered questionnaire surveys with students studying in Saudi universities. Data were analysed using regression analysis. This research finds that the use of Twitter has a positive and statistically significant impact on all four aspects of communicative competence of Saudi higher education students. Keywords: Communicative competence, Twitter and communicative competence, Twitter and language competence, Linguistic competence, discourse competence, strategic language competence, sociolinguistic competence. DOI: 10.7176/NMMC/91-02 Publication date:June 30th 202

Thermally Activated Palm Kernel Based Carbon as a Support for Edible Oil Hydrogenation Catalyst

Activated carbon has distinctive properties as a support for hydrogenation catalysts. Thermally activated carbon has been prepared from palm kernel shell at 1073 K and placed under nitrogen flow for 2 h. It was impregnated by palladium using toluene solution of Pd (acac)2. The Pd/C was reduced using a water solution of potassium borohydride (KBH4). The Pd-B/C was characterized by the Brunauer-Emmett-Teller surface area analysis (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and inductively-coupled plasma mass spectrometry (ICP-MS). Pd-B/C was applied for sunflower oil hydrogenation at a temperature of 373 K, hydrogen pressure of 413.5 kPa and agitation of 1400 rpm for 1 h. Pd-B/C noticeably exhibited a higher overall catalyst activity in comparison to some recently published palladium catalysts

Toxoplasma gondii antibody prevalence in Libyan epileptic children. A contolled study

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Pediatría. Fecha de lectura: 8-09-2017Esta tesis tiene embargado el acceso al texto completo hasta el 8-03-201