Ectomycorrhizal and endophytic fungi associated with <Emphasis Type="Italic">Alnus glutinosa</Emphasis> growing in a saline area of central Poland

Alnus glutinosa (black alder) is a mycorrhizal pioneer tree species with tolerance to high concentrations of salt in the soil and can therefore be considered to be an important tree for the regeneration of forests areas devastated by excessive salt. However, there is still a lack of information about the ectomycorrhizal fungi (EMF) associated with mature individuals of A. glutinosa growing in natural saline conditions. The main objective of this study was to test the effect of soil salinity and other physicochemical parameters on root tips colonized by EMF, as well as on the species richness and diversity of an EMF community associated with A. glutinosa growing in natural conditions. We identified a significant effect of soil salinity (expressed as electrical conductivity: EC_e and EC_1:5) on fungal taxa but not on the total level of EM fungal colonization on roots. Increasing soil salinity promoted dark-coloured EMF belonging to the order Thelephorales (Tomentella sp. and Thelephora sp.). These fungi are also commonly found in soils polluted with heavy-metal. The ability of these fungi to grow in contaminated soil may be due to the presence of melanine, a natural dark pigment and common wall component of the Thelephoraceae that is known to act as a protective interface between fungal metabolism and biotic and abiotic environmental stressors. Moreover, increased colonization of fungi belonging to the class of Leotiomycetes and Sordiomycetes, known as endophytic fungal species, was observed at the test sites, that contained a larger content of total phosphorus. This observation confirms the ability of commonly known endophytic fungi to form ectomycorrhizal structures on the roots of A. glutinosa under saline stress conditions.     

New Rapid Method of DNA Isolation from Milk Somatic Cells

Isolation of genomic DNA is one of the basic steps in many different molecular analyses. There are a few reports on methods of DNA isolation from milk, but many of them are time consuming and expensive, and require relatively large volumes of raw milk. In this study a rapid, sensitive, and efficient method of DNA extraction from milk somatic cells of various mammals (cattle, sheep, goats, horses) is presented. It was found that milk is a good source of genomic DNA, and to obtain a sufficient amount and quality of DNA, suitable for molecular analysis such as PCR, 10 mL of raw milk is sufficient. Thanks to this method, stress in animals can be reduced during collection of researched material. Therefore, this method could be widely used in molecular analyses.     

Occurrence of the aacA4 gene among multidrug resistant strains of Pseudomonas aeruginosa isolated from bronchial secretions obtained from the Intensive Therapy Unit at University Hospital in Bialystok, Poland

The aim of this study was to investigate the prevalence of the aacA4 gene in a population of multidrug resistant strains of P. aeruginosa isolated from bronchial secretions obtained from the Intensive Therapy Unit (ITU). Twelve MDR isolates were tested for antibiotic susceptibility and the presence of the aacA4 gene. In this study, 58.3% of the strains contained (6')-Ib' aminoglycoside acetyltransferase gene. All of the studied strains (aacA4-positive and aacA4-negative) were susceptible only to colistine (100%). Among other antibiotics, the lowest resistance rates were those shown against ceftazidime (14.3% to 20%) and imipenem (28.6% to 40%). Our studies frequently revealed the presence of the aacA4 gene as a factor responsible for resistance; it is probable that other mechanisms of resistance to aminoglycoside antibiotics also occurred.     

Alignment of the genomes of Brachypodium distachyon and temperate cereals and grasses using bacterial artificial chromosome landing with fluorescence in situ hybridization

As part of an initiative to develop Brachypodium distachyon as a genomic "bridge" species between rice and the temperate cereals and grasses, a BAC library has been constructed for the two diploid (2n = 2x = 10) genotypes, ABR1 and ABR5. The library consists of 9100 clones, with an approximate average insert size of 88 kb, representing 2.22 genome equivalents. To validate the usefulness of this species for comparative genomics and gene discovery in its larger genome relatives, the library was screened by PCR using primers designed on previously mapped rice and Poaceae sequences. Screening indicated a degree of synteny between these species and B. distachyon, which was confirmed by fluorescent in situ hybridization of the marker-selected BACs (BAC landing) to the 10 chromosome arms of the karyotype, with most of the BACs hybridizing as single loci on known chromosomes. Contiguous BACs colocalized on individual chromosomes, thereby confirming the conservation of genome synteny and proving that B. distachyon has utility as a temperate grass model species alternative to rice.