The Occurrence of Multidrug-Resistant Pseudomonas aeruginosa on Hydrocarbon-Contaminated Sites

The main aim of this paper was the comprehensive estimation of the occurrence rate and the antibiotic-resistance conditions of opportunistic pathogen Pseudomonas aeruginosa in hydrocarbon-contaminated environments. From 2002 to 2007, 26 hydrocarbon-contaminated sites of Hungary were screened for the detection of environmental isolates. Altogether, 156 samples were collected and examined for the determination of appearance, representative cell counts, and antibiotic-resistance features of P. aeruginosa. The detected levels of minimal inhibitory concentrations of ten different drugs against 36 environmental strains were compared to the results of a widely used reference strain ATCC 27853 and four other clinical isolates of P. aeruginosa. Based on our long-term experiment, it can be established that species P. aeruginosa was detectable in case of 61.5% of the investigated hydrocarbon-contaminated sites and 35.2% of the examined samples that shows its widespread occurrence in polluted soil–groundwater systems. In the course of the antibiotic-resistance assay, our results determined that 11 of the examined 36 environmental strains had multiple drug-resistance against several clinically effective antimicrobial classes: cephalosporins, wide spectrum penicillins, carbapenems, fluoroquinolones, and aminoglycosides. The fact that these multiresistant strains were isolated from 8 different hydrocarbon-contaminated sites, mainly from outskirts, confirms that multiple drug-resistance of P. aeruginosa is widespread not only in clinical, but also in natural surroundings as well.     

Microaerobic enrichment of benzene-degrading bacteria and description of Ideonella benzenivorans sp. nov., capable of degrading benzene,toluene and ethylbenzene under microaerobic conditions

In the present study, the bacterial community structure of enrichment cultures degrading benzene under microaerobic conditions was investigated through culturing and 16S rRNA gene Illumina amplicon sequencing. Enrichments were dominated by members of the genus Rhodoferax followed by Pseudomonas and Acidovorax. Additionally, a pale amber-coloured, motile, Gram-stain-negative bacterium, designated B7^T was isolated from the microaerobic benzene-degrading enrichment cultures and characterized using a polyphasic approach to determine its taxonomic position. The 16S rRNA gene and whole genome-based phylogenetic analyses revealed that strain B7^T formed a lineage within the family Comamonadaceae, clustered as a member of the genus Ideonella and most closely related to Ideonella dechloratans CCUG 30977^T. The sole respiratory quinone is ubiquinone-8. The major fatty acids are C_16:0 and summed feature 3 (C_16:1 ω7c/iso-C_15:0 2-OH). The DNA G?+?C content of the type strain is 68.8?mol%. The orthologous average nucleotide identity (OrthoANI) and in silico DNA–DNA hybridization (dDDH) relatedness values between strain B7^T and closest relatives were below the threshold values for species demarcation. The genome of strain B7^T, which is approximately 4.5?Mb, contains a phenol degradation gene cluster, encoding a multicomponent phenol hydroxylase (mPH) together with a complete meta-cleavage pathway including a I.2.C-type catechol 2,3-dioxygenase (C23O) gene. As predicted by the genome, the type strain is involved in aromatic hydrocarbon-degradation: benzene, toluene and ethylbenzene are degraded aerobically and also microaerobically as sole source of carbon and energy. Based on phenotypic characteristics and phylogenetic analysis, strain B7^T is a member of the genus Ideonella and represents a novel species for which the name Ideonella benzenivorans sp. nov. is proposed. The type strain of the species is strain B7^T (=?LMG 32,345^T?=?NCAIM B.02664^T).

     

Preservation of elastic system fibers and of collagen molecular arrangement and stainability in an Egyptian mummy

Summary The present findings show that both elastic system fibers and collagen markedly resisted change in tissues more than 2000 years old.The distribution of elastic fibers and elastic-related fibers (namely, oxytalan and elaunin fibers) in mummified tissues coincided with the observations made on the modern human tissues used as controls.The collagenous structures present in tissue sections obtained from the Egyptian mummy studied took on a deeply red colour when stained in the Picrosirius solution indicating that, as well as in the fresh controls, the basic groups in the collagen molecules were available for reacting with the strongly acidic dye Sirius Red. When viewed with polarized light, the collagen in the same tissue sections displayed an increased birefringence, which shows that the collagen molecules in mummified tissues maintain the oriented disposition which is typical of the modern human tissues used as controls.The methods employed have proved to be useful for the delineation of the elastic system fibers and of the collagenous scaffolding, which may be used as valuable landmarks in the study of the histoarchitecture of organs that have undergone considerable distortion.Supported in part by Grant no. 43.83.0610/00 from Financiadora de Estudos e Projetos (FINEP-FNDCT). G.S. Montes is Career Investigator of the Brazilian National Research Council (CNPq)     

Thermophilic fungi in air samples in surroundings of compost piles of municipal,agricultural and horticultural origin

In this study, the effect of the thermophilic fungi of composts was analysed on the fungal composition of the air above. Air samples were collected with an Andersen air sampler at 1.5 m height in three large industrial composting facilities treating different waste types. Repetition was collected on three calm and rain-free days of three consecutive weeks in October 2011, in January, April and July 2012; five plates were exposed successively per sampling day. Compost samples were also collected (averaging 1 kg/compost piles). Air and compost samples were cultured at 50 °C. The thermophilic fungal composition of the air near the compost piles of different waste types differed significantly (p < 0.05) from that of the control site above a grassland ecosystem at each sampling time. Seasonal differences could be detected regarding the total number of thermophilic fungi in the air near the agricultural and horticultural compost types, but smaller differences were found near the municipal compost type. A total of 13 and 11 fungal species were detected in the compost and air samples where the dominant species were Thermomyces lanuginosus and Rasamsonia emersonii, respectively. The concentration of airborne thermophilic fungi was higher near the horticultural compost type and lower near the municipal compost. The results suggest that the differences between the incidences of some species in composts and associated aerosols refer to spore ontogeny and biological mechanisms of spore liberation.     

Histochemical and morphological characterization of reticular fibers

The results presented in this paper show that collagen fibers can be clearly distinguished from reticular fibers using the picrosirius-polarization method. A morphologic and morphometric study of these two types of fibers with electron microscopy shows that reticular fibers are characterized by the smaller diameter of their fibrillar components and the higher content of interfibrillar material, resulting in a loose arrangement of the fibrils. The evidences presented suggest that the amorphous matrix in which fibrils are embedded is responsible for the silver impregnation of reticular fibers. Our results show that the matrix of reticular fibers is characteristically rich in heparitin sulfate, and that the glycosaminoglycans present show a high interaction with the fibrillar component of these fibers.     

De novo genome project of Cupriavidus basilensis OR16

Here we report on the complete genome sequence of Cupriavidus basilensis OR16 NCAIM BO2487. The genome of strain OR16 contains 7,534 putative coding sequences, including a large set of xenobiotics-degrading genes and a unique glucose dehydrogenase gene that is absent from other Cupriavidus genomes.     

De novo genome project for the aromatic degrader Rhodococcus pyridinivorans strain AK37

Here, we present the complete genome sequence of Rhodococcus pyridinivorans AK37 strain NCAIM PB1376, which was isolated from an oil-polluted site in Hungary. R. pyridinivorans AK37 is an aerobic, nonsporulating, nonmotile, gram-positive bacterium with remarkable aromatic-decomposing activity.     

The collagen of the vertebrate peripheral nervous system

Summary Nerves and ganglia from a variety of fish, amphibian, reptilian and mammalian species were studied by optical and electron microscopy. Observations using the Picrosirius-polarization method strongly suggest that two different types of collagen fibers are present in the connective tissues of nerves and ganglia. Electron microscopy of nerves and ganglia showed the presence of two different collagen fibril populations, distinguishable on the basis of diameter, located in different compartments of these structures. Thicker fibrils are present in nerve and ganglionic epineurium. Thinner fibrils are present in the endoneurium, surrounding nerve fibers and ganglionic cells, and between the concentric layers of perineurial cells. These results were consistently observed in all species studied and very probably represent a general phenomenon in vertebrates.This work was aided by a grant from the Fundação de Amparo à Pesquisa do Estado de São Paulo