Tarek Moussa

Extremophiles are a group of organisms growing in a wide range of extreme environmental conditions. The extremophilic microorganisms are diverse and are classified into psychrophiles (− 2°C to 20°C), thermophiles (55–121°C), piezophiles (> 500atm), halophiles (2–5M NaCl or KCl), metallophiles (high concentrations of metals, e.g., copper, zinc, lead, cadmium, and arsenic), alkaliphiles (pH>8), and acidophiles (pH<4) according to the extreme environmental conditions in which they grow and can tolerate. The aims of this chapter are to characterize the extremophilic microorganisms and their physiological and molecular efficiencies in bioremediation processes. Interestingly, the remarkable adaptative abilities of extremophilic microorganisms make them an attractive source of biocatalysts for bioremediation. Bioremediation is an important technology for the cleanup of environmental contaminants. Further attention has also been directed to isolation, identification, and characterization of biocatalysts from extremophilic microorganisms, most of them enzymes named extremozymes, which are well adapted to be active also at extreme conditions. Extremozymes are expected to fill the gap between biological and chemical industrial processes because of the remarkable properties of these enzymes. Even though more than 3000 different enzymes have been identified till now, and many of these were used in industrial and biotechnological applications, the enzyme toolbox at the present is still not enough to present demands. A major cause for this is the fact that many available enzymes do not withstand industrial reaction conditions.

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Due to the significance of the antimicrobial peptides as innate immune effectors, in this study, a novel bovine antimicrobial peptide and its antimicrobial spectrum were described. RNA isolation from various tissues and RT-PCR were conducted. The DCD-like peptide was synthesized, and its antimicrobial effect was analyzed. The bovine dermcidin-like gene contains 5 exons intermittent by 4 introns. Bovine DCD-like mRNA was 398 bp with ORF size of 336 bp. Bovine DCD-like was expressed in skin and blood. Analysis of amino acid compositions showed that cysteine was repeated six times, which indicates the presence of 3 disulfide bonds that play a role in the peptide stability. Bovine DCD-like had an antimicrobial effect on Enterococcus faecalis, Streptococcus bovis, and  Staphylococcus epidermidis, which was highest at 50 and 100 µg/ml. The effect on Candida albicans and Escherichia coli was slightly low. In Staphylococcus aureus, the activity of bovine DCD-like was affected greatly at pH 4.5 and 5.5. The optimum salt concentrations were 50 and 100 mM with E. coli and all other bacterial strains, respectively. In C. albicans, the activity of bovine DCD-like decreased with increasing pH regardless of the concentration of NaCl. The pH 6.5 of the sweat buffer was optimum for the activity of bovine DCD-like. Finally, it was concluded that the bovine DCD-like gene expressed in skin cells and the DCD-like peptide secreted into the sweat, had high antimicrobial activities against many Gram-positive and -negative strains, as well as yeast-like fungus. 

The transcription factors families (TFs) play a critical role in the response regulation of plants to abiotic stresses. The three plant lineages (E. desvauxii, C. colocynthis & Z. simplex) can be separated on the PC1 level, while R. stricta and S. Italica can be distinguished from each other on the PC2 level. A unique 225 transcripts in each of R. stricta and E. desvauxii, 85 transcripts in C. colocynthis, 92 transcripts in S. Italica, and 41 transcripts in Z. simplex were identified. All five plants were shared in only 15 transcripts. Genes had significant gene ontology (GO), R. stricta (450), E. desvauxii (475), C. colocynthis (197), S. Italica (223), and Z. simplex (75) were significantly assigned with GO terms for 29 transcriptional processes. The most abundant TF families in the five plants were MYB followed by, MYB-related, bHLH, and AP2-EREBP (1105, 803, 53 & 472 transcripts, respectively). The zinc TF families were the most transcribed and represented by 8 TF families (PLATZ, C2C2-CO-like, C3H, VOZ, C2C2-GATA, C2C2-DOF, C2H2 & ZF-HD), with the highest one (C3H TF family, 99 transcripts in both R. stricta & Z. simplex). The regulatory network showed that as heat response, 12 genes were upregulated in R. stricta and controlled several genes in some vital processes inside the plant, while E. desvauxii and S. Italica respond to heat by upregulation of 6 genes for each, C. colocynthis by regulation of 3 genes and the least one was Z. simplex by upregulation of two genes only.

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The gene (pox1) encoding a phenol oxidase 1 from Pleurotus ostreatus was sequenced and the corresponding pox1-cDNA was also synthesized, cloned and sequenced. The isolated gene is flanked by an upstream region called the promoter (399 bp) prior to the start codon (ATG). The putative metal-responsive elements (MREs) were determined in the promoter region, where MRE 1, 2 and 3 were located in positions -20, -62 and -389, respectively. Functional TATA consensus sequences were recognized in positions -78 and -245, while CAAT consensus sequence was recognized in position -171. The putative GC boxes consensus sequences were recognized in positions -175 and -344, and xenobiotic-responsive elements (XREs) in positions -100 and -270. The pox1-DNA gene consists of 2656 bp, with the coding sequence being interrupted by 19 introns. The nucleotide sequence of cDNA (pox1-cDNA) was found to contain an ORF of 1590 bp capable of coding for a protein of 529 amino acid residues. The signal peptide was predicted to be 23 amino acids in length using SIGNALP 3.0 program. Northern blot analysis revealed that strong transcriptional induction was observed in the copper-supplemented cultures for pox1 gene.