Assessment of genetic diversity and phylogenetic relationship of local coffee populations in southwestern Saudi Arabia using DNA barcoding.

The genetic diversity of local coffee populations is crucial to breed new varieties better adapted to the increasingly stressful environment due to climate change and evolving consumer preferences. Unfortunately, local coffee germplasm conservation and genetic assessment have not received much attention. Molecular tools offer substantial benefits in identifying and selecting new cultivars or clones suitable for sustainable commercial utilization. New annotation methods, such as chloroplast barcoding, are necessary to produce accurate and high-quality phylogenetic analyses. This study used DNA barcoding techniques to examine the genetic relationships among fifty-six accessions collected from the southwestern part of Saudi Arabia. PCR amplification and sequence characterization were used to investigate the effectiveness of four barcoding loci: atpB-rbcl, trnL-trnF, trnT-trnL, and trnL. The maximum nucleotide sites, nucleotide diversity, and an average number of nucleotide differences were recorded for atpB-rbcl, while trnT-trnL had the highest variable polymorphic sites, segregating sites, and haploid diversity. Among the four barcode loci, trnT-trnL recorded the highest singleton variable sites, while trnL recorded the highest parsimony information sites. Furthermore, the phylogenetic analysis clustered the Coffea arabica genotypes into four different groups, with three genotypes (KSA31, KSA38, and KSA46) found to be the most divergent genotypes standing alone in the cluster and remained apart during the analysis. The study demonstrates the presence of considerable diversity among coffee populations in Saudi Arabia. Furthermore, it also shows that DNA barcoding is an effective technique for identifying local coffee genotypes, with potential applications in coffee conservation and breeding efforts.

Flow Injection Techniques for Tetracycline Quantification: A Review.

The multiple therapeutic potentials of tetracycline and its worldwide usage have encouraged researchers to develop various methods for its assay in various matrices and for different purposes. In this regard, different analytical techniques have been exploited. Among those techniques is flow injection (FI), which is an extended family of three generations and five versions. The current manuscript reviews the utilization of FI techniques for developing assay methods for tetracycline. The review covers more than forty methods, since the inception of FI techniques and up to date. The review highlights the advantages of the application of FI techniques for quantification of tetracycline in terms of reagent consumption, sample frequency, accuracy, and practitioner safety, besides instrumentation simplicity and cost-effectiveness. The review also addresses applications to several matrices ranging from simple matrices such as standard solutions and pharmaceutical formulations to complex matrices such as biological fluids and food. Prior to the review, a brief background on the principles and developments of FI techniques is illustrated.

GC-MS analysis of Myrtus communis extract and its antibacterial activity against Gram-positive bacteria.

BACKGROUND: Myrtus communis is a typical plant of Mediterranean area. The different parts of this plant such as berries, branches, and leaves have been used worldwide as a traditional/folk medicine for the treatment of various ailments and diseases. METHODS: Ethanolic leaf extract of the plant was prepared by Soxhlet extraction method. Zone of inhibition, minimum inhibitory concentration and minimal bactericidal concentration were determined by well diffusion method and microplate alamar blue assay. GC-MS analysis was carried out to identify the compounds present in the extract. Microscopy and ImageJ software were used respectively for morphology and cell-length measurements. GraphPad Prism was used for statistical analysis. RESULTS: The ethanolic extract showed strong inhibitory effect against Gram-positive and acid-fast bacteria with significant inhibition-zone size (9-25 mm), MIC (4.87-78 µg/ml), as well as MBC (0.3-20 mg/ml). However, no effect was observed on the growth of Gram-negative bacteria. The growth inhibition was found to be associated with the damage of cell wall as the extract-treated cells were sensitive to cell wall-targeting antibiotics and displayed the cell wall damage-depicting morphological defects. GC-MS analysis confirmed the presence of novel compounds in addition to the most representative compounds of the essential oils/extracts of M. communis of other country origins. CONCLUSION: These results demonstrate that M. communis leaf extract could be the source of compounds to be used for the treatment of Gram-positive bacterial infections. This is the first report, which provides insights into the mechanism of action of the extract in inhibiting the growth of Gram-positive bacteria.

Levels of zinc, copper, cadmium, and lead in fruits and vegetables grown and consumed in Aseer Region, Saudi Arabia.

The levels of four metals (Zn, Cu, Cd, and Pb) were evaluated in two fruit types (apricot and fig), a fruity vegetable (tomato), and three leafy vegetables (arugula, spinach, and lettuce) that are commonly grown and consumed in Aseer Region, Saudi Arabia. Flame atomic absorption spectrophotometry was employed for quantification. The quality of results was checked by a certified reference material (NIST SRM 1570a). Good recovery values in the range of 87-104% were achieved. Metals were quantified in washed and unwashed samples to evaluate the effect of washing. Statistically, no significant difference was noticed (p>0.05), except for Zn in arugula and Cu in apricot and spinach. The levels of metals found in the analyzed fruits and vegetables were in their normal ranges in crops and not posing any serious risks to the consumers in Aseer Region. The toxic elements Pb and Cd were well below the maximum levels set in the Saudi and international food standards. Zn and Cu levels were comparable to the ranges reported in worldwide previous studies.

The effect of loading palladium on zinc oxide on the photocatalytic degradation of methyl tert-butyl ether (MTBE) in water.

A series of heterogeneous catalysts was prepared by doping zinc oxide with different palladium loadings in the range of 0.5%-1.5%. The prepared catalysts were characterized by SEM, TEM and XRD. These catalysts were applied to study the degradation of Methyl tert-Butyl Ether (MTBE). An amount of 100 mg of each of these catalysts was added to an aqueous solution of 100 ppm of MTBE. The resulting mixtures were irradiated with UV light for a period of 5 h. A 99.7% removal of MTBE was achieved in the case of the zinc oxide photocatalyst particles doped with 1% Pd. The photoreaction was found to be a first-order one.

Production of tyrosol by Candida albicans biofilms and its role in quorum sensing and biofilm development.

Tyrosol and farnesol are quorum-sensing molecules produced by Candida albicans which accelerate and block, respectively, the morphological transition from yeasts to hyphae. In this study, we have investigated the secretion of tyrosol by C. albicans and explored its likely role in biofilm development. Both planktonic (suspended) cells and biofilms of four C. albicans strains, including three mutants with defined defects in the Efg 1 and Cph 1 morphogenetic signaling pathways, synthesized extracellular tyrosol during growth at 37 degrees C. There was a correlation between tyrosol production and biomass for both cell types. However, biofilm cells secreted at least 50% more tyrosol than did planktonic cells when tyrosol production was related to cell dry weight. The addition of exogenous farnesol to a wild-type strain inhibited biofilm formation by up to 33% after 48 h. Exogenous tyrosol appeared to have no effect, but scanning electron microscopy revealed that tyrosol stimulated hypha production during the early stages (1 to 6 h) of biofilm development. Experiments involving the simultaneous addition of tyrosol and farnesol at different concentrations suggested that the action of farnesol was dominant, and 48-h biofilms formed in the presence of both compounds consisted almost entirely of yeast cells. When biofilm supernatants were tested for their abilities to inhibit or enhance germ tube formation by planktonic cells, the results indicated that tyrosol activity exceeds that of farnesol after 14 h, but not after 24 h, and that farnesol activity increases significantly during the later stages (48 to 72 h) of biofilm development. Overall, our results support the conclusion that tyrosol acts as a quorum-sensing molecule for biofilms as well as for planktonic cells and that its action is most significant during the early and intermediate stages of biofilm formation.