Genetic structure in Brazilian breeding colonies of the Roseate Spoonbill (Platalea ajaja, Aves: Threskiornithidae)

Roseate Spoonbills (Platalea ajaja, Linnaeus) are wading birds present in two of the most important Brazilian wetlands: the Pantanal wetlands and Rio Grande do Sul marshes. Natural populations of these species have not been previously studied with variable nuclear molecular markers. In order to support decision making regarding the management and conservation of these populations, we estimated and characterized the distribution of genetic variability among five Brazilian breeding colonies. The average observed heterozygosity in Brazilian Roseate Spoonbill populations (Ho = 0.575) did not differ significantly from the value determined in a U.S. wild-caught sample of 15 individuals, using data generated by the same set of microsatellite loci. Considering that the U.S. population underwent a recent reduction in size, we discuss this result supposing that the U.S. population was not genetically affected or that both populations had suffered a bottleneck. Global F(ST) indicated the lack of genetic differentiation among colonies, indicating the occurrence of past and/or present gene flow among them. Analysis of molecular variance revealed that most of the genetic variation is distributed within the colonies. Results are explained by a recent origin of colonies or by high levels of gene flow. Management decisions should take into consideration the fact that, even in the presence of high genetic exchange, ecological adaptations to different environments are important for species survival.     

Characterization of 1,3-propanediol oxidoreductase (DhaT) from <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> J2B

1,3-propanediol oxidoreductase (DhaT) of Klebsiella pneumoniae converts 3-hydroxypropionaldehyde (3-HPA) to 1,3-propanediol (1,3-PD) during microbial production of 1,3-PD from glycerol. In this study, DhaT from newly isolated K. pneumoniae J2B was cloned, expressed, purified, and studied for its kinetic properties. It showed, on its physiological substrate 3-HPA, higher activity than similar aldehydes such as acetaldehyde, propionaldehyde and butyraldehyde. The turnover numbers (k _cat , 1/s) were estimated as 59.4 for the forward reaction (3-HPA to 1,3-PD at pH 7.0) and 10.0 for the reverse reaction (1,3-PD to 3-HPA at pH 9.0). The Michaelis constants (K _m , mM) were 0.77 (for 3-HPA) and 0.03 (for NADH) for the forward reaction (at pH 7.0), and 7.44 (for 1,3-PD) and 0.23 (for NAD⁺) for the reverse reaction (at pH 9.0). Between these forward and reverse reactions, the optimum temperature and pH were significantly different (37°C and 7.0 vs. 55°C and 9.0, respectively). These results indicate that, under physiological conditions, DhaT mostly catalyzes the forward reaction. The enzyme was seriously inhibited by heavy metal ions such as Ag⁺ and Hg²⁺. DhaT was highly unstable when incubated with its own substrate 3-HPA, indicating the necessity of enhancing its stability for improved 1,3-PD production from glycerol.     

Geobacillus toebii subsp. decanicus subsp. nov., a hydrocarbon-degrading, heavy metal resistant bacterium from hot compost

A thermophilic, spore-forming bacterial strain L1(T) was isolated from hot compost "Pomigliano Environment" s.p.a., Pomigliano, Naples, Italy. The strain was identified by using a polyphasic taxonomic approach. L1(T) resulted in an aerobic, gram-positive, rod-shaped, thermophilic with an optimum growth temperature of 68 degrees C chemorganotrophic bacterium which grew on hydrocarbons as unique carbon and energy sources and was resistant to heavy metals. The G+C DNA content was 43.5 mol%. Phylogenetic analysis of 16S rRNA gene sequence and Random Amplified Polymorphic DNA-PCR (RAPD-PCR) analysis of L1(T) and related strains showed that it forms within Geobacillus toebii, a separate cluster in the Geobacillus genus. The composition of cellular fatty acids analyses by Gas-Mass Spectroscopy differed from that typical for the genus Geobacillus in that it is lacking in iso-C15 fatty acid, while iso-C16 and iso-C17 were predominant. Isolates grew on a rich complex medium at temperatures between 55-75 degrees C and presented a doubling time (t(d)) of 2 h and 6 h using complex media and hydrocarbon media, respectively. Among hydrocarbons tested, n-decane (2%) was the more effective to support the growth (1 g/L of wet cells). The microorganism showed resistance to heavy metal tested during the growth. Furthermore, intracellular alpha-galactosidase and alpha-glucosidase enzymatic activities were detectable in the L1(T) strain. Based on phenotypic, phylogenetic, fatty acid analysis and results from DNA-DNA hybridization, we propose assigning a novel subspecies of Geobacillus toebii, to be named Geobacillus toebii subsp. decanicus subsp. nov., with the type strain L1(T) (=DSM 17041=ATCC BAA 1004).     

Planococcus rifietensis sp. nov, isolated from algal mat collected from a sulfurous spring in Campania (Italy)

The taxomony of strain M8, isolated from algal mat formed at the origin of a sulfurous spring in Rifieto (Savignano Irpino, Campania, Italy), was investigated in a polyphasic approach. The morphological, physiological and genetic characteristics were compared with of Planococcus and Planomicrobium species. The isolate grew optimally at pH 9.0, 1.8 M NaCl at 37 degrees C. The cells were Gram-positive cocci that form pairs, tetrads and aggregates of several cells. The isolate was aerobic/microaerophilic and accumulated glycine-betaine, as a major osmolyte, with minor components glutamate and an unknown compound. M8 was able to hydrolyse X-Glc (5-bromo-4-chloro-3-indoyl beta-d-glucopyranoside). The polar lipid profile consisted of phosphatidylglycerol and diphosphatidylglycerol as major components, and phosphocholine as a minor compound. MK8 was the only quinone found and the fatty acid composition was dominated by branched acids, mainly aiC15:0. The G+C content of DNA was 47.9% and its phylogenetic position was established by 16S rRNA gene sequencing as a member of the genus Planococcus. The DNA/DNA similarity of M8 to the type species Planococcus citreus was less than 55%. For this reason and for physiological and chemotaxonomic features, it is proposed to create a new species Planococcus rifietensis sp. nov.     

Presence of Salmonella as a risk to public health in the Caribbean zone of Colombia

Salmonella is frequently involved in diarrhoeal disease throughout the world and is disseminated mainly by food, polluted waters or infected food-handlers. In Colombia, the serotypes of Salmonella and their distribution in food have not been characterized. Therefore, the objective was to establish the epidemiology of Salmonella in the Caribbean zone. Six hundred thirty-six samples were obtained in fast food outlets located in city squares or markets of Barranquilla (n=245), Montería (n=222), Sincelejo (n=87) and Cartagena (n=82). Salmonella was isolated by the conventional methods recommended by the United States Food and Drug Administration. Briefly, 25 g of each sample was inoculated in 225 ml of broth. Twenty-four hours later, a 1 ml aliquot was inoculated onto selective media for Salmonella. Suspicious colonies were identified by conventional biochemical tests and confirmed by conventional serology for Salmonella detection. Forty-seven Salmonella serotypes were isolated from meat (40%), sausage (25%), cheese (13%), pig (13%), chicken (4.2%) and egg 'arepas' (4.2%). The serologic characterization indicated the following serotypes: S. Anatum (26%), S. Newport (13%), S. Typhimurium (9%), S. Gaminara (9%) and S. Uganda (9%). No statistically significant Salmonella isolations among 4 socioeconomic categories were observed (p=0.05). However, differences were observed when rates were compared for Salmonella by food type for socioeconomic categories 1, 2 and 3 (p<0.05), categories 2 and 3 did not show differences between them (p>0.05).     

Method for antibiotic assay on Sulfolobales

Summary The use of antibiotic-discs on Gelrite-medium, for studying antibiotic sensitivity of Sulfolobales, is reported for the first time.This work was partially supported by an Italian target project PFBBCS.