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BACKGROUND: Aflatoxins (AFs) are fungal secondary metabolites produced by Aspergillus flavus. They contaminate of dietary food with AFs is a worldwide problem that affects both food safety and agricultural economies. AIM: The aim of this study was designed to investigate the AFs contents of human food commodities mostly consumed in Jeddah, Saudi Arabia. METHODS: The study was designed in vitro, contents in six food categories. A total of 288 samples were collected from 78 different markets in Jeddah. AFs were determined by high-performance liquid chromatography with fluorescence detector using immunoaffinity column clean-up. RESULTS: The results indicated that the incidence rate 27.3% of nut samples collected from Jeddah, were contaminated with AFB1, AFB2. The concentrations of AFs (AFB1, AFB2, AFG1, and AFG2) were ranged from 0.19–482.4, 0.09–3.34, 0.19–87.1, to 0.09–579 μg/kg in the nut samples. CONCLUSION: The results demonstrate the importance of routine monitoring of AFs contamination in various dry foods for human consumed should be performed regularly and the nuts contained high levels of AFs. The legal regulations must be unauthorized for human consumption to control the health risks associated with AFs.

This review shall provide support for the suitability of arid environments as preferred location to search for unknown lipid-accumulative bacteria. Bacterial lipids are attracting more and more attention as sustainable replacement for mineral oil in fuel and plastic production. The development of prokaryotic microorganisms in arid desert habitats is affected by its harsh living conditions. Drought, nutrient limitation, strong radiation, and extreme temperatures necessitate effective adaption mechanisms. Accumulation of storage lipids as energy reserve and source of metabolic water represents a common adaption in desert animals and presumably in desert bacteria and archaea as well. Comparison of corresponding literature resulted in several bacterial species from desert habitats, which had already been described as lipid-accumulative elsewhere. Based on the gathered information, literature on microbial communities in hot desert, cold desert, and humid soil were analyzed on its content of lipid-accumulative bacteria. With more than 50% of the total community size in single studies, hot deserts appear to be more favorable for lipid-accumulative species then humid soil (≤20%) and cold deserts (≤17%). Low bacterial lipid accumulation in cold deserts is assumed to result from the influence of low temperatures on fatty acids and the increased necessity of permanent adaption methods.

As oleaginous microorganisms represent an upcoming novel feedstock for the biotechnological production of lipids or lipid-derived biofuels, we searched for novel, lipid-producing strains in desert soil. This was encouraged by the hypothesis that neutral lipids represent an ideal storage compound, especially under arid conditions, as several animals are known to outlast long periods in absence of drinking water by metabolizing their body fat. Ten lipid-accumulating bacterial strains, affiliated to the genera Bacillus, Cupriavidus, Nocardia, Rhodococcus and Streptomyces, were isolated from arid desert soil due to their ability to synthesize poly(β-hydroxybutyrate), triacylglycerols or wax esters. Particularly two Streptomyces sp. strains and one Rhodococcus sp. strain accumulate significant amounts of TAG under storage conditions under optimized cultivation conditions. Rhodococcus sp. A27 and Streptomyces sp. G49 synthesized approx. 30% (w/w) fatty acids from fructose or cellobiose, respectively, while Streptomyces isolate G25 reached a cellular fatty acid content of nearly 50% (w/w) when cultivated with cellobiose. The stored triacylglycerols were composed of 30-40% branched fatty acids, such as anteiso-pentadecanoic or iso-hexadecanoic acid. To date, this represents by far the highest lipid content described for streptomycetes. A biotechnological production of such lipids using (hemi)cellulose-derived raw material could be used to obtain sustainable biodiesel with a high proportion of branched-chain fatty acids to improve its cold-flow properties and oxidative stability.

A novel Sphingomonas strain was isolated from a sample of desert soil collected near Jeddah in Saudi Arabia. A polyphasic approach was performed to characterize this strain, initially designated as G39T. Cells of strain G39T are motile, Gram-negative, catalase- and oxidase-positive. The strain is able to grow aerobically at 20-35 °C, pH 6.5-8 and tolerates up to 4 % (w/v) NaCl. Based on 16S rRNA gene sequence similarity, the closest relative type strains of G39T are Sphingomonas mucosissima DSM 17494T (98.6 %), S. dokdonensis DSM 21029T (98.4 %) and S. hankookensis DSM 23329T (97.4 %). Furthermore, the average nucleotide identities between the draft genome sequence of strain G39T and the genome sequences of all other available and related Sphingomonas species are significantly below the threshold of 94 %. The G+C content of the draft genome (3.12 Mbp) is 65.84 %. The prevalent (>5 %) cellular fatty acids of G39T were C18 : 1ω7c, C16 : 1ω7c and/or C16 : 1ω6c, C14 : 0 2-OH and C16 : 0. The only detectable respiratory quinone was ubiquinone-10 and the polar lipids profile is composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipid, as well as unidentified lipids, phospholipids and glycolipids. The results of the conducted polyphasic approach confirmed that this isolate represents a novel species of the genus Sphingomonas, for which the name Sphingomonas jeddahensis sp. nov. is proposed. The type strain of this species is G39T (=DSM 103790T=LMG 29955T). peerReviewed

The control of mosquitoes is an important public health concern around the world. The activity of petroleum ether extracts of Dodonaea viscose, Lantana camara and Ruta chaliphenses have been investigated towards larval development of Aedes aegypti. The plant extracts exhibits variable biological activity against Ae. aegypti. The greatest effect was observed with Dodonaea viscose and Lantana camara. They showed acute LC50 (2days) of 126.2, 136.9 and chronic LC50 (10 days) of 64.6 and 68.5 ppm, respectively. Larvae suffered chronic toxicities leading to 97.8% mortality using Dodonaea viscose and 95.6% using Lantana camara. Egg hatchability was significantly reduced in Dodonaea viscose and Lantana camara concentrations. All extracts concentrations of Dodonaea viscose and Lantana camara as well as higher extract concentration of Ruta chaliphenses caused significant high hindrance of subsequent larval development and consequently reduced both pupation and adult mergence. Drastic retardation of development was shown using Dodonaea viscose extracts (17.3, 7.4%) and Lantana camara extracts (19.3, 9.0%) from larval stage managed to pupal and adult stages, when reared in very low concentration (100 ppm) of the extracts. Ruta chaliphense was only more effective at higher concentrations. Hence, application of these extracts to Ae. aegypti mosquito breeding sites can be used as an innovative valuable alternative to the existing synthetic pesticides for the control of Ae. aegypti.

Electrophoretic analysis of the proteins bound to poly(3-hydroxybutyric acid), PHB-, granules in Methylobacterium extorquens, M. rhodesianum as well as the PHB-leaky mutants Mu 1 and Mu 11, which were isolated from the latter, resulted in two dominant low-molecular weight proteins, which were referred to as GA11 and GA20. After purification of these proteins antibodies against the GA11 and GA20 protein of M. extorquens were obtained. Both proteins bound to the surface of PHB granules as revealed by immunoelectron microscopy of whole cells of M. extorquens and M. rhodesianum. With cells of the PHB-leaky mutants Mu 1 and Mu 11 no specific labeling was observed. The N-terminal amino acid sequences of the GA11 and the GA20 protein were determined. We found significant homologies between the sequences of the investigated strains. The use of oligonucleotide probes based on the N-terminal sequences of the GA20 protein from M. rhodesianum to identify the corresponding structural genes in various genomic libraries failed.

In recent years, glycerol has become an attractive carbon source for microbial processes, as it accumulates massively as a by-product of biodiesel production, also resulting in a decline of its price. A potential use of glycerol in biotechnology is the synthesis of poly(3-hydroxypropionate) [poly(3HP)], a biopolymer with promising properties which is not synthesized by any known wild-type organism. In this study, the genes for 1,3-propanediol dehydrogenase ( dhaT ) and aldehyde dehydrogenase ( aldD ) of Pseudomonas putida KT2442, propionate-coenzyme A (propionate-CoA) transferase ( pct ) of Clostridium propionicum X2, and polyhydroxyalkanoate (PHA) synthase ( phaC1 ) of Ralstonia eutropha H16 were cloned and expressed in the 1,3-propanediol producer Shimwellia blattae . In a two-step cultivation process, recombinant S. blattae cells accumulated up to 9.8% � 0.4% (wt/wt [cell dry weight]) poly(3HP) with glycerol as the sole carbon source. Furthermore, the engineered strain tolerated the application of crude glycerol derived from biodiesel production, yielding a cell density of 4.05 g cell dry weight/liter in a 2-liter fed-batch fermentation process.

Isolation of polyhydroxyalkanoates (PHAs) from bacterial cell matter is a critical step in order to achieve a profitable production of the polymer. Therefore, an extraction method must lead to a high recovery of a pure product at low costs. This study presents a simplified method for large scale poly(3-hydroxybutyrate), poly(3HB), extraction using sodium hypochlorite. Poly(3HB) was extracted from cells of Ralstonia eutropha H16 at almost 96% purity. At different extraction volumes, a maximum recovery rate of 91.32% was obtained. At the largest extraction volume of 50 L, poly(3HB) with an average purity of 93.32% ± 4.62% was extracted with a maximum recovery of 87.03% of the initial poly(3HB) content. This process is easy to handle and requires less efforts than previously described processes.

Frequent spontaneous loss of the magnetic phenotype was observed in stationary-phase cultures of the magnetotactic bacteriumMagnetospirillum gryphiswaldenseMSR-1. A nonmagnetic mutant, designated strain MSR-1B, was isolated and characterized. The mutant lacked any structures resembling magnetosome crystals as well as internal membrane vesicles. The growth of strain MSR-1B was impaired under all growth conditions tested, and the uptake and accumulation of iron were drastically reduced under iron-replete conditions. A large chromosomal deletion of approximately 80 kb was identified in strain MSR-1B, which comprised both the entiremamABandmamDCclusters as well as further putative operons encoding a number of magnetosome-associated proteins. A bacterial artificial chromosome clone partially covering the deleted region was isolated from the genomic library of wild-typeM. gryphiswaldense. Sequence analysis of this fragment revealed that all previously identifiedmamgenes were closely linked with genes encoding other magnetosome-associated proteins within less than 35 kb. In addition, this region was remarkably rich in insertion elements and harbored a considerable number of unknown gene families which appeared to be specific for magnetotactic bacteria. Overall, these findings suggest the existence of a putative large magnetosome island inM. gryphiswaldenseand other magnetotactic bacteria.

The boundary layer of PHA inclusion bodies isolated from Chromatium vinosum, Pseudomonas oleovorans, and Rhodococcus ruber was investigated by negative staining and transmission electron microscopy. A typical boundary layer exhibits a basic lattice composed of regularly arranged phasin molecules and phospholipids, forming a thin, nevertheless mechanically stable cover surrounding the content of the inclusion body. Depending on the bacterial strain under investigation, the lattice parameters of the boundary layer may vary. Usually, values between 3.3 and 9.6nm are observed for the spacing, and the lattice is rectangular. Enzyme particles interpreted as PHA synthase particles are attached to, or inserted into the basic lattice. They cover not more than 20% of the total surface of the inclusion body. These enzyme particles measure between 8 and 12nm in diameter, are made up of subunits and occur as single units or small aggregates. No indications have been obtained which would support the view that the boundary layer is a double-layer of proteins with phospholipids in between. Rather, a visual inspection of detached boundary layers revealed that the boundary layer is a monolayer exhibiting only one kind of basic lattice. In regions where this monolayer had been artificially removed from the inclusion body, the surface of the contents of the inclusion body was exposed.