Sarfaraz Hadi

Biodegradation of diesel fuel hydrocarbons by mangrove fungi from Red Sea Coast of Saudi Arabia.

Mangrove sediments were collected from major mangrove stands on the Red Sea Coast of Saudi Arabia. Forty five isolates belonging to 12 genera were purified and five isolates as well as their consortium were found to be able to grow in association with petroleum oil as sole carbon source under in vitro conditions. The isolated strains were identified based on internal transcribed spacer (ITS) rDNA sequence analysis. The fungal strains with the greatest potentiality to degrade diesel oil, without developing antagonistic activity, were identified as Alternaria alternata, Aspergillus terreus, Cladosporium sphaerospermum, Eupenicillium hirayamae and Paecilomyces variotii. As compared to the controls, these fungi accumulated significantly higher biomass, produced extracellular enzymes and liberated larger volumes of CO2. These observations with GC–MS data confirm that these isolates displayed rapid diesel oil bioremoval and when used together as a consortium, there was no antagonistic activity.

Effect of some biotic factors on microbially-induced calcite precipitation in cement mortar

Sporosarcina pasteurii, a common soil bacterium has been tested for microbial treatment of cement mortar. The present study also seeks to investigate the effects of growth medium, bacterial concentration and different buffers concerning the preparation of bacterial suspensions on the compressive strength of cement mortar. Two growth media, six different suspensions and two bacterial concentrations were used in the study. The influence of growth medium on calcification efficiency of S. pasteurii was insignificant. Significant improvement in the compressive as well as the tensile strength of cement mortar was observed. Microbial mineral precipitation visualized by Scanning Electron Microscopy (SEM) shows fibrous material that increased the strength of cement mortar. Formation of thin strands of fillers observed through SEM micrographs improves the pore structure, impermeability and thus the compressive as well as the tensile strengths of the cement mortar. The type of substrate and its molarity have a significant influence on the strength of cement mortar.

Histopathological studies of experimental Aeromonas hydrophila infection in blue tilapia, Oreochromis aureus

Blue tilapia, Oreochromis aureus, was experimentally infected with Aeromonas hydrophila, a bacterium that damages the gills, liver, and intestine, resulting in histopathological changes in the infected organs. Our histopathological study showed an aggregation of hemocytes with cell necrosis in gills; a massive aggregation of hemocytes and pyknotic nuclei in the hepatopancreas; and a lower rate of hemocyte aggregation in the digestive system of the infected fish.

Biodegradation of Low Density Polyethylene (Ldpe) by Mangrove Fungi from the Red Sea Coast

Forty five fungal isolates belonging to 13 genera were derived from tidal water, floating debris, and sediment collected from mangrove stands on the Red Sea coast of Saudi Arabia. Six of these isolates and their consortium were found to be able to grow in association with low density polyethylene (LDPE) film under in vitro conditions in the absence of dextrose or any other carbon source. These isolates were further tested for their potential to degrade LDPE by co-cultivation under aeration on a rotary shaker. Examination under light and scanning electron microscope revealed that the fungi attached themselves to the surface of the film and grew profusely. As compared to the controls, these fungi accumulated significantly higher biomass, produced more ligninolytic enzymes, and released larger volumes of CO2 during co-cultivation with LDPE. These observations indicated that the selected isolates were able to breakdown and consume the LDPE film.

Biodegradation of engine oil by fungi from mangrove habitat

The pollution of land and water by petroleum compounds is a matter of growing concern necessitating the development of methodologies, including microbial biodegradation, to minimize the impending impacts. It has been extensively reported that fungi from polluted habitats have the potential to degrade pollutants, including petroleum compounds. The Red Sea is used extensively for the transport of oil and is substantially polluted, due to leaks, spills, and occasional accidents. Tidal water, floating debris, and soil sediment were collected from mangrove stands on three polluted sites along the Red Sea coast of Saudi Arabia and forty-five fungal isolates belonging to 13 genera were recovered from these samples. The isolates were identified on the basis of a sequence analysis of the 18S rRNA gene fragment. Nine of these isolates were found to be able to grow in association with engine oil, as the sole carbon source, under in vitro conditions. These selected isolates and their consortium accumulated greater biomass, liberated more CO2, and produced higher levels of extracellular enzymes, during cultivation with engine oil as compared with the controls. These observations were authenticated by gas chromatography-mass spectrophotometry (GC-MS) analysis, which indicated that many high mass compounds present in the oil before treatment either disappeared or showed diminished levels.

Hormonal basis of 'shees' fruit abnormality in tissue culture derived plants of date palm.

‘Shees’ fruit abnormality manifested as cluster of small fruit-like structures on a single peduncle occurs at a high frequency in tissue culture derived plants of date palm. The abnormality is akin to parthenocarpy, which is known to be caused by altered hormone profile of flowers/fruits in many species. This study was conducted to elucidate the hormonal profile of date palm flowers and early fruits and to identify the hormones associated with ‘shees’ fruit formation. Hormone levels in young flowers/fruits of normal and ‘shees’-bearing plants of cultivars ‘Barhy’ and ‘Nabtet-Saif’ were studied with HPLC at the time of pollination and subsequently after 10 and 20 days. In all these samples, out of seven hormones detected by HPLC, levels of indole-3-acetic acid (IAA) and gebberellic acid (GA3) were significantly higher, while that of a ‘kinetin-like’ compound and an unknown compound were significantly lower in ‘shees’ flowers/fruits as compared to the normal counterparts. Other three unknown compounds did not show significant variations between normal and ‘shees’ fruits. Kinetin-like compound showed the same elution properties as kinetin standard during HPLC procedures. The compound was purified and an attempt was made to characterize the molecule with gas chromatography-mass spectrometry (GC-MS). On the basis of Wiley-229 library hit (entry 101383) the compound was identified as Benzeldehyde, 2-hydroxy-[(2-hydroxyphenyl) methylene] hydrazone with formula: C14H12N2O2 and Mol weight: 240. We have tentatively designated the compound as BHH and are reporting the occurrence of this compound for the first time in date palm.

MEDIUM SUPPLEMENTS AND SUPPORT MATRICES FOR BETTER IN VITRO GROWTH OF DATE PALM (PHOENIX DACTYLIFERA L.)

Despite its extensive use as gelling agent for tissue culture media, agar possesses many shortcomings including impurities, scarcity and high cost in local markets and sensitivity to the harsh local environment. In view of the need to find alternative gelling agents or solid support matrices, growth and development of date palm (Phoenix dactylifera L.) cultures were evaluated on polyurethane (PU) foam discs in comparison with agar-gelled medium. Incorporating activated charcoal in tissue culture media has been shown to affect growth and development of various organisms. It plays a critical role in the micropropagation of date palms by adsorbing inhibitory compounds in media and decreasing toxic metabolites, phenolic exudation and brown exudate accumulation. However, in some cases activated charcoal adsorbs hormones required for the callus growth and shoot development thereby retarding active growth. A comparative study of in vitro growth responses of two date palm cultivars in the medium containing charcoal and no charcoal showed significant differences in all the growth parameters. Date palm cultures growing on PU foam showed significantly superior rates of shoot multiplication and shoot elongation as compared to cultures in agar-gelled media. The rooting response of cultures on PU foam and agar-gelled media was nearly similar. It is argued that enhanced aeration and better suited physical characteristics of the material may be the reasons for superior performance of PU foam as support matrix in comparison with agar. It is therefore suggested that a polyurethane matrix can be used satisfactorily for micropropagation of date palms. The poor response of date palm cultures in the charcoal containing medium may be attributed to the lowering of pH of medium during autoclaving as reported by earlier workers thereby inhibiting the uptake of required growth regulators. Polyurethane can also be used for special applications where low pH of culture medium is required, and its composition and resulting physical properties may be precisely modified during manufacture to suit specific culture requirements. At the same time the matrix is very cheap as compared to agar even in a single use cycle. INTRODUCTION Different types of media supplements and support matrices are used in plant tissue culture to enhance growth and development of explants. Activated charcoal has been used in tissue culture media to improve culture growth and promote morphogenesis in a wide variety of species (Wann et al., 1997). Activated charcoal is often used in plant tissue culture to improve cell growth and development (Pan and van Staden, 1998). It plays a critical role in the micropropagation of date palms by adsorbing inhibitory compounds in media and decreasing toxic metabolites, phenolic exudation and brown exudate accumulation. However, there are reports that, in addition to adsorbing unwanted substances, it may also adsorb needed hormones (Ebert and Taylor, 1990; Ebert et al., 1993; Nissen and Sutter, 1990) vitamins (Weatherhead et al., 1979; Pan and van Staden, a abujawad@kacst.edu.sa Proc. 4 Int. Date Palm Conference Eds.: A. Zaid and G.A. Alhadrami Acta Hort. 882, ISHS 2010 816 1998), or metal ions such as Cu and Zn (Van Winkle et al., 2003). In vitro cultures require a surface to grow on. For this reason agar is widely used to gel plant tissue culture media and provide a physical support to the growing cultures. Agar possesses many peculiar properties that suit its use as gelling agent in tissue culture media. It is chemically inert in the medium and is not digested by plant enzymes (Henderson and Kinnersley, 1988). It also forms a uniform gel that remains stable over the range of pH, temperature, and light conditions maintained during incubation. However, despite the above characteristics, performance of agar as a gelling agent is not always consistent. The quality of agar and corresponding performance of cultures has been found to vary from brand to brand presumably due to varying levels of impurities (Scholten and Pierik, 1998; Nairn et al., 1995; Debergh, 1983). Agar also hinders aeration in the medium and may curtail availability of oxygen to the cultures (Newell et al., 2003; Anon., 1988). Besides its qualitative shortcomings, agar constitutes the single costliest component of tissue culture media (Puchooa et al., 1999; Bhattacharya et al., 1994). There might be variation in the price of agar of different brands at different locations, but the predominance of its cost would remain overbearing. Due to its qualitative deficiencies and high cost several attempts have been made to find cheaper alternatives to agar that should put up better or similar performance of cultures as well. Starches from cassava (Maliro and Lameck, 2004; Gerbe and Sathyanarayana, 2001), corn (Puchooa et al., 1999; Hendersen and Kinnersley, 1988), sago (Bhattacharya et al., 1994), and potato (Calleberg et al., 1989), etc. have proved variable efficiencies as gelling agents in culture media. Some gums like gellan gum (Puchooa et al., 1999; Calleberg et al., 1989), gum-katira obtained from bark of Cochlospermum religiosum have also been found to impart good gel strength to the medium (Jain and Babbar, 2002). Among other natural products, microcrystal cellulose (Gorivnova et al., 1993), parenchymatic solidifier from apple (Titel et al., 1987), an agarlike polysaccharide obtained from Pseudomonas (Kang et al., 1982), husk of Plantago ovata seed (Babbar and Jain, 1998; Bhattacharya et al., 1994) have been tried. These materials have ample potential for use as gelling agent and are comparatively cheaper. But their performance has been inconsistent, perhaps due to lack of standardization and presence of impurities. Synthetic solid matrices offer some distinct advantages over agar and other gelling agents. Their quality and properties can be precisely controlled for consistent performance; they are comparatively very cheap, can be reused and are more convenient to handle. Glass beads and glass beads with filter paper (Puchooa et al., 1999) have shown limited superiority over agar. While some synthetic matrices like glass wool cloth, nylon cloth, polystyrene foam (Bhattacharya et al., 1994), polyester-acetate membrane (Matsumoto and Yamaguchi, 1989), polypropylene membrane (Hew et al., 1990; Tanny et al., 1993; Desamero et al., 1993; Adelberg et al., 1992), and polyurethane foam (Conner and Meredith, 1984) have shown promising results. This study was designed to test the utility of polyurethane foam as support matrix during two standard procedures of in vitro plant production, viz., callus mediated somatic embryogenesis and shoot bud proliferation in date palm (Phoenix dactylifera L.). An attempt was also made to compare the efficacy of media with or without charcoal in the somatic embryogenesis and further growth of date palms. MATERIALS AND METHODS Explant Preparation and Sterilization Two elite cultivars of date palm, ‘Sukkary’ and ‘Mosaifah’ were used for the experiment. Tissue from the apical region of 2-3-year-old offshoot was used as explant. The top 8-10 cm portion was excised and was treated twice with 1.0% solution of sodium hypochlorite for 20 and 10 min respectively followed by treatment with 0.2% solution of mercuric chloride for 5 min. Tween-20 (2-3 drops per 100 ml) was added to both the