Antibacterial activity of extracts of marine algae from the Red Sea of Jeddah, Saudi Arabia

In the present study, marine algae were collected from the southern coast of Jeddah, Saudi Arabia during summer and autumn 2009. The antibacterial activities of petroleum ether, diethyl ether, ethyl acetate and  methanol extracts of marine algae belonging to the Chlorophyta, Phaeophyta and Rhodophyta were studied. Their crude extracts were tested against different types of Gram-positive bacteria (Bacillus subtilis,  Methicillin-Resistant Staphylococcus aureus (MRSA) and Staphylococcus aureu) and Gram-negative bacteria  (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). All marine algae extracts tested  exhibited a broad spectrum of antibacterial activity. The maximum inhibition activities were shown for  extracts of Padina pavonica and Turbinaria triquetra. The growth inhibitions of bacteria by Sargassum  portieriatum extracts were higher in samples collected during autumn than that investigated in summer. The  maximum inhibitory effect of Gracilaria multipartita was observed in the petroleum ether extract against B.  subtilis and E. coli. The ethyl acetate and petroleum ether extract of Enteromorpha prolifera and Ulva reticulata  showed strong activity against the tested bacteria. The tested microorganisms that were susceptible to the most effective extracts were further tested for the minimum inhibitory concentration (MIC).  The MIC of the tested microorganisms was between 0.5 and 1.25 µg/ml. The results of the present study confirmed the potential use of marine algae as a good source of antibacterial agent.Key words: Chlorophyta, Phaeophyta, Rhodphyta, gram-positive bacteria, gram-negative bacteria,  solvent extract, minimum inhibitory concentration (MIC)

Inhibition of the development of pathogenic fungi by extracts of some marine algae from the red sea of Jeddah, Saudi Arabia

In this study, the predominant marine algae were collected from three different sites in the coastal area of Al-Kumrah at south of the Red sea of Jeddah, during summer and autumn 2009. The different marine algae belonged to Chlorophyta (Enteromorpha prolifera and Ulva reticulata), Phaeophyta (Cystoseira myrica, Padina pavonica, Sargassum portieriatum and Turbinaria triquetra) and Rhodophyta (Gracilaria multipartita). Algal extraction was achieved successively by using petroleum ether, diethyl ether, ethyl acetate and methanol. The algae extracts were tested in vitro for antifungal activity against Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and the yeast Candida albicans, by using agar-well diffusion method. The crude extracts of the tested algae revealed differences in their bioactivities. The maximum growth inhibition for fungi was recorded in ethyl acetate extract of T. triquetra against C. albicans (30 mm), methanol extract of E. prolifera (29 mm) and ethyl acetate extract of Padina pavonica (28 mm) against A. fumigatus. The results clarified that Chlorophyta and Phaeophyta exhibited the highest biological activity against the tested fungi, whereas the lowest was achieved in Rhodophyta. The minimal inhibitory concentrations (MICs) of the crude extracts of the tested algae ranged from 0.5 to 3.0 μg/ml. The results confirmed the potential of seaweed extracts as a natural source of antimicrobial compounds. The antifungal activity of different extracts of marine algae which belongs to Chlorophyta, Phaeophyta and Rhodophyta were examined against A. flavus, A. fumigatus, A. niger and the yeast C. albicans. The algae belonging to Chlorophyta and Phaeophyta exhibited the highest inhibitory effect against the test pathogenic fungi. The different extracts showed different activities against fungi. The antimicrobial activity depended on both algal species and the efficiency of solvents in the extraction of bioactive substances.Keywords: Green algae, brown algae, red algae, solvent extracts, antifungal activity, minimal inhibitory concentrations (MICs

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

\ud In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis. A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2). Candida albicans was the most frequently isolated species from 250 (84.5%) patients followed by C. glabrata from 20 (6.8%) patients, and C. krusei from 10 (3.4%) patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients. C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.\u

A comprehensive evaluation of colonic mucosal isolates of Sutterella wadsworthensis from inflammatory bowel disease

Peer reviewedPublisher PD

The microaerophilic microbiota of de-novo paediatric inflammatory bowel disease: the BISCUIT study

<p>Introduction: Children presenting for the first time with inflammatory bowel disease (IBD) offer a unique opportunity to study aetiological agents before the confounders of treatment. Microaerophilic bacteria can exploit the ecological niche of the intestinal epithelium; Helicobacter and Campylobacter are previously implicated in IBD pathogenesis. We set out to study these and other microaerophilic bacteria in de-novo paediatric IBD.</p> <p>Patients and Methods: 100 children undergoing colonoscopy were recruited including 44 treatment naïve de-novo IBD patients and 42 with normal colons. Colonic biopsies were subjected to microaerophilic culture with Gram-negative isolates then identified by sequencing. Biopsies were also PCR screened for the specific microaerophilic bacterial groups: Helicobacteraceae, Campylobacteraceae and Sutterella wadsworthensis.</p> <p>Results: 129 Gram-negative microaerophilic bacterial isolates were identified from 10 genera. The most frequently cultured was S. wadsworthensis (32 distinct isolates). Unusual Campylobacter were isolated from 8 subjects (including 3 C. concisus, 1 C. curvus, 1 C. lari, 1 C. rectus, 3 C. showae). No Helicobacter were cultured. When comparing IBD vs. normal colon control by PCR the prevalence figures were not significantly different (Helicobacter 11% vs. 12%, p = 1.00; Campylobacter 75% vs. 76%, p = 1.00; S. wadsworthensis 82% vs. 71%, p = 0.312).</p> <p>Conclusions: This study offers a comprehensive overview of the microaerophilic microbiota of the paediatric colon including at IBD onset. Campylobacter appear to be surprisingly common, are not more strongly associated with IBD and can be isolated from around 8% of paediatric colonic biopsies. S. wadsworthensis appears to be a common commensal. Helicobacter species are relatively rare in the paediatric colon.</p&gt

Numerical modeling of the impact of pump wavelength on Yb-doped fiber amplifier performance

Ytterbium-doped optical amplifiers have become common tools for industrial applications due to their high efficiency, relatively low cost and potentially very high output power level. The efficiency of an ytterbium-doped fiber amplifier depends mainly on the absorption of pump radiation, and, therefore, optimum pump wavelengths have been proposed such as 915 nm. However, the semiconductor pump diodes batch supplied by manufacturers may exhibit a spread in the output wavelength. This paper theoretically investigates the performance of Yb-doped amplifiers for different pump wavelengths and defines the pump power penalty when the pump source does not emit at the optimum wavelength. The penalty has been defined as normalized excess pump power required to achieve the desired gain

Detection and identification of human Plasmodium species with real-time quantitative nucleic acid sequence-based amplification

BACKGROUND: Decisions concerning malaria treatment depend on species identification causing disease. Microscopy is most frequently used, but at low parasitaemia (<20 parasites/μl) the technique becomes less sensitive and time consuming. Rapid diagnostic tests based on Plasmodium antigen detection do often not allow for species discrimination as microscopy does, but also become insensitive at <100 parasites/μl. METHODS: This paper reports the development of a sensitive and specific real-time Quantitative Nucleic Acid Sequence Based Amplification (real-time QT-NASBA) assays, based on the small-subunit 18S rRNA gene, to identify the four human Plasmodium species. RESULTS: The lower detection limit of the assay is 100 – 1000 molecules in vitro RNA for all species, which corresponds to 0.01 – 0.1 parasite per diagnostic sample (i.e. 50 μl of processed blood). The real-time QT-NASBA was further evaluated using 79 clinical samples from malaria patients: i.e. 11 Plasmodium. falciparum, 37 Plasmodium vivax, seven Plasmodium malariae, four Plasmodium ovale and 20 mixed infections. The initial diagnosis of 69 out of the 79 samples was confirmed with the developed real-time QT-NASBA. Re-analysis of seven available original slides resolved five mismatches. Three of those were initially identified as P. malariae mono-infection, but after re-reading the slides P. falciparum was found, confirming the real-time QT-NASBA result. The other two slides were of poor quality not allowing true species identification. The remaining five discordant results could not be explained by microscopy, but may be due to extreme low numbers of parasites present in the samples. In addition, 12 Plasmodium berghei isolates from mice and 20 blood samples from healthy donors did not show any reaction in the assay. CONCLUSION: Real-time QT-NASBA is a very sensitive and specific technique with a detection limit of 0.1 Plasmodium parasite per diagnostic sample (50 μl of blood) and can be used for the detection, identification and quantitative measurement of low parasitaemia of Plasmodium species, thus making it an effective tool for diagnostic purposes and useful for epidemiological and drug studies

Mechanical, durability and thermal properties of foamed concrete reinforced with synthetic twisted bundle macro-fibers

The use of foamed concrete (FC) in the construction sector has been rapidly growing over the past few years as a result of the several advantages it possesses in comparison to traditional high-strength concrete. FC, on the other hand, suffers from a number of deficiencies, such as brittleness, limited ductility, high porosity, excessive drying shrinkage, little resistance to cracking and deformation. To improve the tensile strength and fracture resistance of FC, engineers usually opt for steel fibre or polymer fibre as the reinforcement material of choice. Hence this research aims to investigate the potential utilization of synthetic twisted bundle macro-fibers (SF) in FC to enhance its durability, mechanical and thermal properties. The SF were included in the FC in varied amounts of weight fractions, including 0%, 1%, 2%, 3%, 4%, and 5% respectively. FC was produced at three low densities, precisely 1,000, 1,300, and 1,600 kg/m3, which were all prepared. Compression, flexural, splitting tensile, flow table, porosity, water absorption and thermal conductivity tests were conducted to establish the thermal, mechanical and durability properties of SF-reinforced FC. The findings imply that the integration of SF into FC results in a significant enhancement of the material’s strength and thermal conductivity properties while simultaneously lowering the material’s capacity for water absorption and porosity. For the purpose of improving the material’s mechanical, durability and thermal properties, the weight percentage of SF that was ideal ranged from 3% to 4%. The incorporation of SF into FC resulted in a rise in the material’s ductility, and the specimens maintained their integrity from the loading stage to failure. The SF is able to lessen the cracks that were already present in the FC and prevent the formation of additional cracks in the FC

Optical character recognition on heterogeneous SoC for HD automatic number plate recognition system

Automatic number plate recognition (ANPR) systems are becoming vital for safety and security purposes. Typical ANPR systems are based on three stages: number plate localization (NPL), character segmentation (CS), and optical character recognition (OCR). Recently, high definition (HD) cameras have been used to improve their recognition rates. In this paper, four algorithms are proposed for the OCR stage of a real-time HD ANPR system. The proposed algorithms are based on feature extraction (vector crossing, zoning, combined zoning, and vector crossing) and template matching techniques. All proposed algorithms have been implemented using MATLAB as a proof of concept and the best one has been selected for hardware implementation using a heterogeneous system on chip (SoC) platform. The selected platform is the Xilinx Zynq-7000 All Programmable SoC, which consists of an ARM processor and programmable logic. Obtained hardware implementation results have shown that the proposed system can recognize one character in 0.63 ms, with an accuracy of 99.5% while utilizing around 6% of the programmable logic resources. In addition, the use of the heterogenous SoC consumes 36 W which is equivalent to saving around 80% of the energy consumed by the PC used in this work, whereas it is smaller in size by 95%

Inter-hemispheric EEG coherence analysis in Parkinson's disease : Assessing brain activity during emotion processing

Parkinson’s disease (PD) is not only characterized by its prominent motor symptoms but also associated with disturbances in cognitive and emotional functioning. The objective of the present study was to investigate the influence of emotion processing on inter-hemispheric electroencephalography (EEG) coherence in PD. Multimodal emotional stimuli (happiness, sadness, fear, anger, surprise, and disgust) were presented to 20 PD patients and 30 age-, education level-, and gender-matched healthy controls (HC) while EEG was recorded. Inter-hemispheric coherence was computed from seven homologous EEG electrode pairs (AF3–AF4, F7–F8, F3–F4, FC5–FC6, T7–T8, P7–P8, and O1–O2) for delta, theta, alpha, beta, and gamma frequency bands. In addition, subjective ratings were obtained for a representative of emotional stimuli. Interhemispherically, PD patients showed significantly lower coherence in theta, alpha, beta, and gamma frequency bands than HC during emotion processing. No significant changes were found in the delta frequency band coherence. We also found that PD patients were more impaired in recognizing negative emotions (sadness, fear, anger, and disgust) than relatively positive emotions (happiness and surprise). Behaviorally, PD patients did not show impairment in emotion recognition as measured by subjective ratings. These findings suggest that PD patients may have an impairment of inter-hemispheric functional connectivity (i.e., a decline in cortical connectivity) during emotion processing. This study may increase the awareness of EEG emotional response studies in clinical practice to uncover potential neurophysiologic abnormalities