Soad H. Abou-El-Ela

Novel and Unexpected Prokaryotic Diversity in Water and Sediments of the Alkaline, Hypersaline Lakes of the Wadi An Natrun, Egypt

The phylogenetic diversity of the bacterial and archaeal community in the water and sediments of three large lakes of the Wadi An Natrun was investigated using 16S rRNA clone libraries. The bacterial community was diverse: 769 clones formed 345 operational taxonomic units (OTUs) defined at 99% 16S rRNA sequence identity. The bacterial community in both the water and sediments of the lakes was dominated by clones affiliated with the low G + C Gram-type-positive group, α-proteobacteria, and Bacteroidetes, (11–39, 11–30, and 10–37% of OTUs observed, respectively), patterns that have been observed in previously described alkaline, athalassohaline systems. However, a relatively high proportion of Firmicutess-related clones in the water of the lakes and α-proteobacteria in the sediments was observed. The bacterial community composition of the water and sediment of the same lake and of different lakes was significantly different (p < 0.05). Operational taxonomic units related to the γ-proteobacteria were more abundant in the sediment of Lake Fazda, whereas the sediment of Lake UmRisha was dominated by members of the δ-proteobacteria. The proportion of γ-proteobacterial and Bacteroidetes-affiliated OTUs were predominant in the water of Lake UmRisha and differed significantly from other lake waters (chi-squared analysis, p ≤ 0.01). The more oxygenated and dilute nature of Lake Hamra was reflected in its microbial community composition, with the abundance of Bacillales sequences in the water, the absence of Halanaerobiales, Clostridiales, and Archaea in the water, and the presence of representatives of more phyla such as the Actinobacteria, Spirochaetes, and Verrucomicrobia. The archaeal community composition appeared less diverse: 589 clones resulted in 198 OTUs defined at 99% 16S rRNA sequence identity, and all sequences fell into the phylum Euryarchaeota. Phylogenetic analysis showed that many of the sequences were distantly related (83–90% 16S rRNA sequence identity) to cultured and uncultured archaea, with many clones forming clusters that branched deeply within the Euryarchaeota. Forty-two and 53% of the bacterial and archaeal clones had less than 90% 16S rRNA sequence identity to previously described sequences. This indicates that the water and sediments of the Wadi An Natrun harbor a unique and novel prokaryotic diversity that is different from what has been described among other alkaline, athalassohaline lakes.

Effects of acute exposure to the radiofrequency fields of cellular phones on plasma lipid peroxide and antioxidase activities in human erythrocytes.

Radiofrequency fields of cellular phones may affect biological systems by increasing free radicals, which appear mainly to enhance lipid peroxidation, and by changing the antioxidase activities of human blood thus leading to oxidative stress. To test this, we have investigated the effect of acute exposure to radiofrequency fields of commercially available cellular phones on some parameters indicative of oxidative stress in 12 healthy adult male volunteers. Each volunteer put the phone in his pocket in standby position with the keypad facing the body. The parameters measured were lipid peroxide and the activities of superoxide dismutase (SOD), total glutathione peroxidase (GSH-Px) and catalase. The results obtained showed that the plasma level of lipid peroxide was significantly increased after 1, 2 and 4 h of exposure to radiofrequency fields of the cellular phone in standby position. Moreover, the activities of SOD and GSH-Px in human erythrocytes showed significant reduction while the activity of catalase in human erythrocytes did not decrease significantly. These results indicate that acute exposure to radiofrequency fields of commercially available cellular phones may modulate the oxidative stress of free radicals by enhancing lipid peroxidation and reducing the activation of SOD and GSH-Px, which are free radical scavengers. Therefore, these results support the interaction of radiofrequency fields of cellular phones with biological systems.

Isolation, Phylogenetic Analysis and Anti-infective Activity Screening of Marine Sponge-Associated Actinomycetes

Terrestrial actinomycetes are noteworthy producers of a multitude of antibiotics, however the marine representatives are much less studied in this regard. In this study, 90 actinomycetes were isolated from 11 different species of marine sponges that had been collected from offshore Ras Mohamed (Egypt) and from Rovinj (Croatia). Phylogenetic characterization of the isolates based on 16S rRNA gene sequencing supported their assignment to 18 different actinomycete genera representing seven different suborders. Fourteen putatively novel species were identified based on sequence similarity values below 98.2% to other strains in the NCBI database. A putative new genus related to Rubrobacter was isolated on M1 agar that had been amended with sponge extract, thus highlighting the need for innovative cultivation protocols. Testing for anti-infective activities was performed against clinically relevant, Gram-positive (Enterococcus faecalis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria, fungi (Candida albicans) and human parasites (Leishmania major, Trypanosoma brucei). Bioactivities against these pathogens were documented for 10 actinomycete isolates. These results show a high diversity of actinomycetes associated with marine sponges as well as highlight their potential to produce anti-infective agents.

Bacterial Community Analyses of Two Red Sea Sponges

Red Sea sponges offer potential as sources of novel drugs and bioactive compounds. Sponges harbor diverse and abundant prokaryotic communities. The diversity of Egyptian sponge-associated bacterial communities has not yet been explored. Our study is the first culture-based and culture-independent investigation of the total bacterial assemblages associated with two Red Sea Demosponges, Hyrtios erectus and Amphimedon sp. Denaturing gradient gel electrophoresis fingerprint-based analysis revealed statistically different banding patterns of the bacterial communities of the studied sponges with H. erectus having the greater diversity. 16S rRNA clone libraries of both sponges revealed diverse and complex bacterial assemblages represented by ten phyla for H. erectus and five phyla for Amphimedon sp. The bacterial community associated with H. erectus was dominated by Deltaproteobacteria. Clones affiliated with Gammaproteobacteria were the major component of the clone library of Amphimedon sp. About a third of the 16S rRNA gene sequences in these communities were derived from bacteria that are novel at least at the species level. Although the overall bacterial communities were significantly different, some bacterial groups, including members of Alphaproteobacteria, Gammaproteobacteria, Acidobacteria, and Actinobacteria, were found in both sponge species. The culture-based component of this study targeted Actinobacteria and resulted in the isolation of 35 sponge-associated microbes. The current study lays the groundwork for future studies of the role of these diverse microbes in the ecology, evolution, and development of marine sponges. In addition, our work provides an excellent resource of several candidate bacteria for production of novel pharmaceutically important compounds.

Evaluation of glutathione S-transferase P1 genetic variants affecting type-2 diabetes susceptibility and glycemic control.

Introduction Type 2 diabetes mellitus (T2DM) is associated with increased production of reactive oxygen species and a reduction in antioxidant defenses leading to oxidative stress. Glutathione S-transferases (GSTs) modulate oxidative stress. The present cross-sectional study was aimed at investigating the association between the GSTP1 gene polymorphism and T2DM and to clarify their effect on the glycemic control parameters. Material and methods From the Egyptian population, we enrolled 112 T2DM patients and 188 healthy controls matched for age, sex and origin. Serum lipid profile, blood-glucose level, glycated hemoglobin (HbA1c) and body mass index (BMI) were measured. DNA was extracted from the blood samples. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to measure GSTP1 Ile105Val gene polymorphism of study participants. Results The frequency of the Val allele in exon 5 of the GSTP1 gene in patients with T2DM was higher than that observed in healthy controls (15.2% vs. 9.6%); the difference was considered statistically significant when compared to Ile allele carriers (p = 0.03). The presence of the GSTP1 heterozygous mutant allele Ile/Val was more common in subjects with T2DM than in the control group (30.4% and 19.2%, respectively; p = 0.02). Variation in the GSTP1 gene was associated with BMI (p = 0.02) and not associated with glycemic control parameters (fasting serum glucose and HbA1c) or smoking-related risk of T2DM. Conclusions GSTP1 gene polymorphism may play a significant role in increasing the susceptibility to and risk of T2DM and obesity regardless of smoking status and had no apparent effect on HbA1c in patients with diabetes mellitus.

Manzamines: A potential for novel cures

Manzamines are a unique class of β-carboline marine alkaloids with an unusual tetra- or pentacyclic system. These alkaloids have shown a variety of bioactivities against infectious diseases, cancer and inflammatory diseases. The greatest potential for the manzamine alkaloids appears to be against malaria, with improved potency relative to chloroquine and artemisinin. Over 80 manzamine-related alkaloids have been isolated from more than 16 species of marine sponges belonging to five families distributed from the Red Sea to Indonesia, which suggests a possible microbial origin for manzamine alkaloids. The current review summarizes marine literature, focusing on the biological activities of manzamines, the possible microbial origin of this class of compounds and the Red Sea as a possible source of manzamines from biosynthetic gene clusters of Red Sea microbes.Manzamines are a unique class of β-carboline marine alkaloids with an unusual tetra- or pentacyclic system. These alkaloids have shown a variety of bioactivities against infectious diseases, cancer and inflammatory diseases. The greatest potential for the manzamine alkaloids appears to be against malaria, with improved potency relative to chloroquine and artemisinin. Over 80 manzamine-related alkaloids have been isolated from more than 16 species of marine sponges belonging to five families distributed from the Red Sea to Indonesia, which suggests a possible microbial origin for manzamine alkaloids. The current review summarizes marine literature, focusing on the biological activities of manzamines, the possible microbial origin of this class of compounds and the Red Sea as a possible source of manzamines from biosynthetic gene clusters of Red Sea microbes.

Molecular and protein characterization of two species of the latrunculin-producing sponge Negombata from the Red Sea

Red Sea sponges offer a potential for production of novel drugs and prototypes. The genus Negombata is a type of sponges abundant in the Red Sea. This sponge produces latrunculins that have well documented antitumor activity in addition to antimicrobial and antiviral effects. The identification of Negombata species is based on morphology and microscopical examination of megascleres of spicules. However, these criteria have proven to be unreliable for identification. Therefore, this study was established to test the accuracy of the spicules based taxonomy against molecular and protein profiles for the two species of Negombata: N. magnifica and N. corticata. About 700 bp of cytochrome c oxidase I gene was sequenced from the tissues of the two Negombata species. Additionally total proteins were extracted from Negombata samples collected from different locations during different seasons and separated by denaturing polyacrylamide gel electrophoresis. Characteristic different protein profiles were obtained for both species. The data obtained from cytochrome c oxidase I gene sequencing and protein profiles can reliably differentiate between different species of Negombata in the Red Sea.