Diversity and Antimicrobial Activities of Actinobacteria Isolated from Mining Soils in Midelt Region, Morocco.

Multidrug-resistant bacteria have emerged as a serious global health threat that requires, more than ever before, an urgent need for novel and more effective drugs. In this regard, the present study sheds light on the diversity and antimicrobial potential of Actinobacteria isolates in mining ecosystems. We have indeed investigated the production of bioactive molecules by the Actinobacteria isolated from abandoned mining areas in Midelt, Morocco, where average contents of lead (Pb) and cadmium (Cd) are higher than normal world levels. One hundred and forty-five Actinobacteria isolates were isolated and characterized based on morphological, chemotaxonomical, biochemical, and molecular data. Most of the 145 isolates were identified as Streptomyces. Isolates affiliated to the genera Amycolatopsis, Lentzea, Actinopolymorpha, and Pseudonocardia were also found. Antimicrobial producing potentials of Actinobacteria isolates were assessed against eight test microorganisms Gram+ and Gram- bacteria and yeast. Out of 145 isolates, 51 showed antimicrobial activities against at least one test microorganism. 31 isolates inhibited only bacteria, 7 showed activity against bacteria and Candida albicans, and 13 displayed activity against C. albicans solely. Our findings suggest that Actinobacteria isolated from natural heavy metal ecosystems may be a valuable source of novel secondary metabolites and therefore of new biotechnologically promising antimicrobial compounds.

Protective Effects of Two Halophilic Crude Extracts from Pseudomonas zhaodongensis and Bacillus stratosphericus against Memory Deficits and Anxiety- and Depression-Like Behaviors in Methionine-Induced Schizophrenia in Mice Focusing on Oxidative Stress Status.

Recently, the implication of oxidative stress in behavioral-like disorders has received a lot of attention. Many studies were interested in searching for new natural compounds with protective effects on behavioral-like disorders by focusing on oxidative stress as the main causal factor. Here, we assess the potential effect of cell-free extracts from halophilic bacteria on memory, anxiety, and depression-related behaviors in mice, as well as on cognitive deficits, negative symptoms, and some oxidative stress biomarkers in methionine-induced mice models of schizophrenia. Firstly, crude extracts of bacteria isolated from the Dead Sea were screened for their effects on memory and anxiety- and depression-like behaviors through Y-maze, elevated plus maze, and forced swimming test, respectively, using two doses 60 mg/kg and 120 mg/kg. Then, 120 mg/kg of two bacterial crude extracts, from two strains designated SL22 and BM20 and identified as Bacillus stratosphericus and Pseudomonas zhaodongensis, respectively, with significant contents of phenolic and flavonoid-like compounds, were selected for the assessment of cognitive and negative symptom improvement, as well as for their effects on oxidative stress status in methionine-induced mice models of schizophrenia using six groups (controls, methionine, crude extracts solely, and combinations of crude extracts and methionine). Results showed that the administration of the crude extracts caused a significant increase in the spontaneous alternations in the Y-maze task, the time spent in open arms of the elevated plus maze, and a decrease in immobility time in the forced swimming test in comparison with the control group. Furthermore, the administration of bacterial extracts seemed to diminish disorders related to cognitive and negative symptoms of schizophrenia and to improve the oxidative state in the temporal lobes, in comparison with the methionine group. Our findings suggest substantial antioxidant and anti-neuropsychiatric effects of the crude extracts prepared from Pseudomonas zhaodongensis strain BM20 and Bacillus stratosphericus strain SL22 and that further studies are needed to purify and to determine the active fraction from the extracts.

Occurrence, molecular and antimicrobial resistance of Enterococcus spp. isolated from raw cow's milk trade by street trading in Meknes city, Morocco.

Background: Enterococcus spp. belongs to a group of pathogens which are responsible for serious infections. This study aims at highlighting the raw milk microbiological contamination and at providing data for prevalence and antimicrobial resistance of Enterococcus spp. isolated from raw cow's milk marketed (without any pasteurization) by street traders. Methods: During the period of May 2015 through April 2016, 150 cow's raw milk samples were collected from street traders in Meknes city. They were examined for the identification of Enterococcus spp. using biochemical tests and 16S rRNA gene sequencing. The antimicrobial susceptibility of the isolates was determined. Results: The results showed that 11.3% (17/150) of samples were positive for the presence of Enterococcus spp., of which 64.7% were identified as Enterococcus faecalis, 17.6% as Enterococcus faecium, 11.8% as Enterococcus durans and 5.9% as Enterococcus hirae. The antimicrobial susceptibility showed that all Enterococcus spp. were resistant to ampicillin. The species E. faecalis, E. faecium, E. durans and E. hirae were resistant to streptomycin, with percentages of 52.9% (9/17), 11.8% (2/17), 11.8% (2/17), and 5.9% (1/17) respectively. All isolated strains of E. faecalis and E. faecium were resistant to tetracycline. The multiple antibiotic resistance index was elevated in the majority of Enterococcus spp., reaching values higher than 0.5, indicating a risk for public health. Conclusion: This study shows that the raw milk consumed by the population is contaminated with strains of Enterococcus resistant to antibiotics used in breeding for prophylactic purposes. This requires raising the awareness of those involved in the production and marketing of milk, so as to take measures to apply good hygienic practices and rationalize the use of zootechnical antibiotics.

A comparative study of the antioxidant scavenging activity of green tea, black tea and coffee extracts: a kinetic approach.

The antioxidant activities of three beverages, coffee, black tea and green tea, along with their major components, were investigated in terms of their reaction with the stable radical 2,2'-diphenyl-2-picrylhydrazyl (DPPH). We used a kinetic approach in parallel with quantification methods based on a fixed end-point to determine the scavenging efficiency of compounds abundant in these beverages during their reaction with DPPH using a stopped-flow spectrophotometer-based method. Ascorbic acid, (+)-catechin, (-)-epigallocatechin, tannic acid, and caffeic acid were selected as model antioxidants to study in coffee, black tea and green tea. We applied a second-order model to demonstrate similarities in the kinetics behavior of beverages and related compounds. Our findings showed the slopes k2(')((mol/L)(-1)s(-1)) and k2max(')((mol/L)(1)s(-1)) exhibited similar and correlated values; we suggest the variation in k2(') as a function of time is more informative about antioxidant properties than reaction with DPPH alone. We also used IC100 to test the reliability of the relative stoichiometry using a new comparative parameter "n", which was calculated as: n=c0DPPHIC100 (mol/L(mol/L)(-1), (mol/L)mlmg(-1) or molg(-1)).