Molecular characterization of two microalgal strains in Egypt and investigation of the antimicrobial activity of their extracts

The emergence of new pathogens and the increasing drug-resistance of recognized ones pose a difficult challenge. One way that this challenge is being addressed is through the discovery of new cost-effective drug resources in the form of bioactive compounds. Algae represent a promising source of bioactive compounds in this regard. In the present research, we used molecular and phylogenetic analysis to isolate and identify two microalgal strains. We found that one strain belonged to the phylum chrysophyta and the other to the cyanobacteria. We also investigated the antimicrobial activity of some of the lipophilic extracts of the two microalgal strains. Several fractions showed high individual antimicrobial bioactivity against multidrug-resistant Salmonella sp., Citrobacter sp., Aspergillus niger and Aspergillus flavus. Fraction III from Poterioochromonas malhamensis showed the highest level of activity against two multidrug-resistant bacterial pathogens. The inhibition zone diameter was 1.4 cm for Salmonella and 1.4 cm for Citrobacter. Meanwhile, another lipophilic fraction from the cyanobacterium Synechocystis salina showed broad-spectrum bioactivity (inhibition zone diameter of 0.9 cm for Aspergillus niger, 1 cm for Citrobacter and 0.9 cm for Salmonella). One lipophilic fraction from Aphanizomenon showed antifungal bioactivity against Aspergillus niger and Aspergillus flavus, where the inhibition zone diameter was 1.1 cm and 1.0 cm, respectively. The study highlights the antimicrobial bioactivity of extracts from local microalgae and emphasizes the importance of carrying out screening programs for those microorganisms

Voltammetric studies of some azo compounds derived from 4-methyl-6,7-dihydroxy coumarin in microemulsion and aqueous media

The cyclic voltammetric(CV) behavior of some azo compounds based on coumarin derivatives  was investigated in microemulsion systems and in aqueous solutions. The obtained results indicated that these compounds undergo an irreversible 4-electron reduction step leading to cleavage of the N=N center with the formation of amine compounds in all media. The effect of medium on the CV parameters was discussed. The total number of electrons involved in the reduction process was determined by controlled potential coulometry. Also, The effect of substituents on the electrode reaction pathway and the kinetic parameters of the electrode process were calculated and discussed. Based on the data obtained the electroreduction mechanism was suggested and discussed

A generalized Robinson-Foulds distance for labeled trees.

The Robinson-Foulds (RF) distance is a well-established measure between phylogenetic trees. Despite a lack of biological justification, it has the advantages of being a proper metric and being computable in linear time. For phylogenetic applications involving genes, however, a crucial aspect of the trees ignored by the RF metric is the type of the branching event (e.g. speciation, duplication, transfer, etc). We extend RF to trees with labeled internal nodes by including a node flip operation, alongside edge contractions and extensions. We explore properties of this extended RF distance in the case of a binary labeling. In particular, we show that contrary to the unlabeled case, an optimal edit path may require contracting "good" edges, i.e. edges shared between the two trees. We provide a 2-approximation algorithm which is shown to perform well empirically. Looking ahead, computing distances between labeled trees opens up a variety of new algorithmic directions.Implementation and simulations available at https://github.com/DessimozLab/pylabeledrf

A generalized Robinson-Foulds distance for labeled trees

Background: The Robinson-Foulds (RF) distance is a well-established measure between phylogenetic trees. Despite a lack of biological justification, it has the advantages of being a proper metric and being computable in linear time. For phylogenetic applications involving genes, however, a crucial aspect of the trees ignored by the RF metric is the type of the branching event (e.g. speciation, duplication, transfer, etc). Results: We extend RF to trees with labeled internal nodes by including a node flip operation, alongside edge contractions and extensions. We explore properties of this extended RF distance in the case of a binary labeling. In particular, we show that contrary to the unlabeled case, an optimal edit path may require contracting “good” edges, i.e. edges shared between the two trees. Conclusions: We provide a 2-approximation algorithm which is shown to perform well empirically. Looking ahead, computing distances between labeled trees opens up a variety of new algorithmic directions. Implementation and simulations available at https://github.com/DessimozLab/pylabeledrf

Embedded two level direct adaptive fuzzy controller for DC motor speed control

AbstractThis paper presents a proposed approach based on an adaptive fuzzy logic controller for precise control of the DC motor speed. In this concern, the proposed Direct Adaptive Fuzzy Logic Controller (DAFLC) is estimated from two levels, where the lower level uses a Mamdani fuzzy controller and the upper level is an inverse model based on a Takagi–Sugeno (T–S) method in which its output is used to adapt the parameters of the fuzzy controller in the lower level. The proposed controller is implemented using an Arduino DUE kit. From the practical results, it is proved that the proposed adaptive controller improves, successfully both the performance response and the disturbance due to the load in the speed control of the DC motor

Sorting by reversals, block interchanges, tandem duplications, and deletions

<p>Abstract</p> <p>Background</p> <p>Finding sequences of evolutionary operations that transform one genome into another is a classic problem in comparative genomics. While most of the genome rearrangement algorithms assume that there is exactly one copy of each gene in both genomes, this does not reflect the biological reality very well – most of the studied genomes contain duplicated gene content, which has to be removed before applying those algorithms. However, dealing with unequal gene content is a very challenging task, and only few algorithms allow operations like duplications and deletions. Almost all of these algorithms restrict these operations to have a fixed size.</p> <p>Results</p> <p>In this paper, we present a heuristic algorithm to sort an ancestral genome (with unique gene content) into a genome of a descendant (with arbitrary gene content) by reversals, block interchanges, tandem duplications, and deletions, where tandem duplications and deletions are of arbitrary size.</p> <p>Conclusion</p> <p>Experimental results show that our algorithm finds sorting sequences that are close to an optimal sorting sequence when the ancestor and the descendant are closely related. The quality of the results decreases when the genomes get more diverged or the genome size increases. Nevertheless, the calculated distances give a good approximation of the true evolutionary distances.</p

Influence of Plant Growth Regulators on Somatic Embryogenesis Induction in Seriphidium herba-album

Seriphidium herba-album (syn. Artemisia herba-alba) is a medicinal, aromatic, greenish-silver herb. It is used widely in folk medicine for treatment of diarrhea, abdominal cramps and in the healing of external wounds. It's also used for the treatment of diabetes mellitus, neurological disorders as epilepsy, Alzheimer's disease, depression and jaundice. In this study we assessed the protocol for callus induction, maturation of somatic embryogenesis, frequency of germination and conversion into plantlets for leaf explants of Seriphidium herba-album using different concentrations of PGRs. Highest induction frequencies of embryogenic calli occurred after 35 days on MS medium supplemented with 1.5 mg L-1 2,4-D and 0.5 mg L-1 BAP. Optimum MS medium for higher frequency of matured somatic embryos was recorded using 5.0 mg L-1 BAP and 0.5 mg L-1 NAA and somatic embryos also induced young in vitro grown plantlets when cultured in the medium containing GA3 and kinetin. Hence, attempts to induce direct somatic embryogenesis have been achieved up to embryo regeneration and maturation

FORMULATION AND ASSESSMENT OF A HERBAL HAIR CREAM AGAINST CERTAIN DERMATOPHYTES

Objective: Developing an herbal antifungal formulation containing eruca and garlic oils against highly resistant dermatophytes (Malassezia fufur AUMC No. 5173, Microsporum canis bodin AUMC No. 5490 and Trichophyton mentagrophytes AUMC No. 5501. 5501) and assessment of garlic oil thiosulfonates during the ex vivo percutaneous permeation through albino rat skin.Methods: Assay of antifungal activity was performed by filter paper disc method and agar well diffusion method. The components of volatile constituents and fixed oil of eruca seeds were studied using GC/MS. Thiosulfinates in garlic oil were analyzed by HPLC/UV. Both oils were incorporated into hair cream using span 60 and brij 58 at three different concentrations (2, 4 and 6% w/w) and alliin, was ex vivo evaluated using albino rat skin mounted on Franz diffusion cells.Results: The two oils have a synergistic effect on the first and additive effect on the second and the third fungi. The main constituents in eruca are 4-(methyl thio) butyl isothiocyanate (82%) for volatile constituents and erucic acid (40%) for the fixed one. The highest flux for alliin (0.337±0.0015 mg/cm2/hr) was obtained at a 4% surfactant concentration.Conclusion: Combination of oils has a high activity on the selected dermatophytes. Formulation of an herbal hair cream using span 60 and Brij 58 with a concentration 4% gives the highest permeation rate for alliin in garlic oil.Keywords: Eruca, Garlic, Dermatophytes, Quantitative determination and Ex-vivo permeatio

Some Heavy Metals Status in Ashtoum El-Gamil Protected Area

ABSTRACT A survey study was conducted on some heavy metals (Pb, Cd, Cu, Zn, and Fe) in water, sediment, and fish samples from Ashtoum El-Gamil protected area during May 2010 to January 2011. Data obtained revealed that there were significant (P≤0.0001) differences among sampling seasons and stations as well as their interactions concerning the levels of heavy metals tested in either water, sediment, or fish collected from this protected area. The elements level took the descending order Zn ≥ Cd ≥ Pb ≥ Fe ≥ Cu in the water, Pb ≥ Fe ≥ Cu ≥ Zn ≥ Cd in the sediment, and Fe ≥ Pb ≥ Zn ≥ Cu ≥ Cd in the fish body samples. Proximate analysis of the tested fish (mullet and tilapia) reflected also significant (P≤0.0001) effects due to sampling seasons and stations and their interactions besides fish species. Some significant correlations were calculated among heavy metals (in water, sediments, and fish) and chemical composition of the fish