Bacteria are diverse and abundant in soils, but only a few bacteria have known to grow on hydrocarboncontaminated areas and utilize complex carbon source such as crude oil for the synthesis of polyhydroxyalkanoate (bioremediation potential and the ability to produce important biopolymers). Among 32 samples collected from several sites of petroleum refinery soil and oily sludge of Iranian southwestern refineries, 45 oil-degrading pseudomonads were identified, and 33 % of the isolated Pseudomonas strains were able to produce polyhydroxyalkanoate using Gachsaran crude oil (2 % v/v) as carbon source. The repeated monomer composition of the copolymer produced from Gachsaran crude oil was determined by gas chromatography/mass spectrometry. The produced monomers composites contained: C 8 (3-hydroxyoctanoate), C 10 (3-hydroxydecanoate), C 12 (2-hydroxydodecanoate), C 14 (3-hydroxytetradecanoate), and C 16 (3-hydroxydecahexanoate), which are known as biopolymers. This study indicates oil-contaminated areas can be important sources for polyhydroxyalkanoate producers which can be used for the bioremediation of crude-oil-polluted sites; also polyhydroxyalkanoate has a functional role in bacterial survival and stress tolerance in the toxic environments and poor nutrient availability.

Bartonellae are emerging vector-borne pathogens infecting various domestic and wild mammals. Blood samples were collected from 66 dogs at two locations near Hamedan, Iran. Twenty dogs were rescued stray dogs and 46 dogs were from a breeding colony, with many of them infested with fleas, ticks, or lice. Serology was performed using an indirect immunofluorescent antibody test for Bartonella henselae, Bartonella clarridgeiae, and Bartonella vinsonii subsp. berkhoffii. Seroprevalence was 74.2% (range: 65.2-95%). Bartonella DNA amplification and sequencing identified B. vinsonii subsp. berkhoffii type III in seven dogs, including five rescued dogs. Two dogs were infected with Bartonella rochalimae and three dogs with Candidatus B. merieuxii, including two of the stray dogs coinfected with Bartonella vinsonii subsp. berkhoffii. Rescued stray dogs were 10 times (odds ratio (OR) = 10.13, 95% CI: 1.24-82.7; P = 0.03) more likely to be seropositive and eight times (OR = 8.82, 95% CI: 2.68-29.11; P = 0.0004) more likely to be flea-infested than breeding dogs, confirming that arthropod infestation is a major risk factor for these infections.

Carbohydrate polymers are industrially and medically important. For instance, a polysaccharide, alginate (from seaweed), is widely used in food, textile and pharmaceutical industries. Certain bacteria also produce alginate through membrane spanning multi-protein complexes. Using Pseudomonas aeruginosa as a model organism, we investigated the biological function of an alginate degrading enzyme, AlgL, in alginate production and biofilm formation. We showed that AlgL negatively impacts alginate production through its enzymatic activity. We also demonstrated that deletion of AlgL does not interfere with polymer length control, epimerization degree or stability of the biosynthesis complex, arguing that AlgL is a free periplasmic protein dispensable for alginate production. This was further supported by our protein-stability and interaction experiments. Interestingly, over-production of AlgL interfered with polymer length control, suggesting that AlgL could be loosely associated with the biosynthesis complex. In addition, chromosomal expression of algL enhanced alginate O-acetylation; both attachment and dispersal stages of the bacterial biofilm lifecycle were sensitive to the level of O-acetylation. Since this modification also protects the pathogen against host defences and enhances other virulence factors, chromosomal expression of algL could be important for the pathogenicity of this organism. Overall, this work improves our understanding of bacterial alginate production and provides new knowledge for alginate production and disease control.

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