Annual Research & Review in Biology

A distinct strain named Micromonospora sp. Rc5 was isolated from Sinai desert of Egypt and recorded high antagonistic activities against some food and bloodborne pathogens. Morphological and chemotaxonomy characterization confirmed that this isolate belongs to genus Micromonospora. Sequencing of partial 16S rDNA and BLASTN showed that isolate Rc5 is identical to Micromonospora haikouensis (99%) but with low bootstrap value in NJ phylogenetic tree. Comprehensive optimization of several growth factors was performed including initial pH, incubation periods, and different sources of carbon and nitrogen. The highest yield of antimicrobial agent production was obtained after 8 days of incubation at 30°C, pH 6.0, 3 x 10⁵CFU/ml in soya bean meal broth media with agitation of 150 rpm. A dramatic proportional decrease occurred with 0.3, 0.6, 0.9 µg active fraction /ml against Staphylococcus aureus culture and reached to complete inhibition at a minimum inhibitory concentration of (1.5 µg /ml). The physicochemical characterization of the purified fraction was identified as phthalate derivative. Our results indicated that Rc5 generated potential antimicrobial compounds against foodborne pathogens and   may combat resistant strains of Staphylococcus aureus.

Even though Arthrospira is a well-known superfood, it is not extensively commercialized in developing countries like Malaysia due to the high production cost with low biomass yield. Based on literature, the algal production cost can be discounted by reducing the cost of medium utilizing cheaper and readily available chemicals. Therefore, the present study was conducted to experiment the prospect of Arthrospira platensis cultivation in newly designed medium with commercial or industrial grade fertilizers under real environment. Consequently, growth and yield of A. platensis was investigated under outdoor condition using modified Kosaric medium (MKM) which was designed by substituting the major laboratory chemicals in standard Kosaric medium (SKM) with commercial grade baking soda, sea salt, urea, phosphoric acid, potassium hydroxide and Epsom salt. Urea as an alternative nitrogen resource to sodium nitrate was pulse-fed throughout the cultivation period. The algal growth was measured through optical density, biomass dry weight and chlorophyll a content. The algal yield was determined by calculating its productivity and specific growth rate. The growth and yield of A. platensis was significantly higher (p < 0.05) in MKM in terms of optical density with 2.541 ABS, biomass dry weight with 1.30 g L^-1, chlorophyll a content with 12.96 mg L^-1, productivity with 0.141 g L^-1 d^-1 and specific growth rate with 0.253 µ d^-1 compared to SKM in eight days of cultivation period. The present finding showed the potential of MKM in lowering the medium cost up to 97% compared to SKM without compromising the algal yield under natural condition with proper cultivation techniques such as preadaptation and fed-batch addition of urea in the late evening.

In this paper, a nonlinear mathematical model is developed and analyzed to study the dynamics of Ebola virus (EVD) and the effects of some control strategies. The model validity is investigated and was found to be locally asymptotically stable when the basic reproduction number  and unstable otherwise. Pontryagin's maximum principle is applied to obtain the optimality conditions. Numerical simulation was carried out and the results obtained indicate that a combination of all three control parameters is highly effective in containing the spread of the virus.

Endomycorrhizal inoculum, consisting of more than 26 mycorrhizal species, has been followed over time at the rhizosphere of olive trees. The evolution during time of this endomycorrhizal inoculum at the rhizosphere of plants has been discussed in this study. After 42 months, 45 species were isolated from the rhizosphere of inoculated olive plants. These species belong to 6 genera (Glomus, Acaulospora, Gigaspora; Scutellospora; Pacispora and Entrophospora), from these genera, Glomus was the most dominant (40%) followed by the Acaulospora (30%). Glomus constrictum and G. intraradices were the most abundant species, their frequency are respectively 17% and 15%. In comparison between detected species, those of primary inoculum and those recovered after 30 months, 36 endomycorrhizal species appeared and 14 species disappeared, but four species G. clarum, G. intraradices, G. mossea and G. versiforme have been able to maintain their status and stability of multiplication in the rhizosphere of olive plants.

Microorganisms have developed several physiological adaptations to survive within extreme ecological niches including environments contaminated with heavy metals, pesticides, polycyclic aromatic hydrocarbons, and nuclear wastes. Microorganisms in extreme habitat are potential source of “novel biomolecule(s)” such as whole microbial cells, extremozymes and extremolytes, significantly required for environmental, industrial, and red medical/pharmaceutical biotechnology. These novel biomolecule(s) are valuable resources and may help improve economic development. The scanty information about the factors governing the microbial growth within stressed environments is the major constraint in the recovery of novel biomolecule(s) from extreme habitats. Understanding the structure, metabolic capabilities, microbial physiology, and factors governing the composition and role of indigenous microorganism is the key to success of any study. In recent past the problems associated with classical cultivation techniques have been resolved by an emerging approach referred to as “metagenomics”. Metagenomic studies give an insight into details of the structure, metabolic and physiological capabilities of indigenous microbial communities. High-throughput sequencing technologies in conjunction with metagenomics has aided in the identification and characterization of novel culturable and uncultured microorganisms with unique capabilities. Metagenomic studies have been used for isolation and characterization of novel biomolecule(s) relevant for white, grey, and red biotechnologies. The major objective of this review is to discuss the applications of metagenomic approach for bioprospection of novel biomolecule(s) and environmental bioremediation.