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The poultry red mite Dermanyssus gallinaeis commonly acknowledged as a serious biological threat to global poultry breeding. This is mostly because of the inefficiency of acaricidal treatments of poultry houses, which does not eliminate the mite population, only constrains it. However, the impact of D. gallinaeon poultry welfare is poorly characterized. The biochemical and cytological characteristics of infection are limited mainly to anaemia, decreased levels of triglycerides in the blood and eosinophilia. For the first time, we report the adverse effects of D. gallinaeinfestation of industrial poultry houses on the functional state of poultry livers. Treatment of poultry houses with acaricidal powder preparation, Wooran-dust 0.7%, containing synthetic pyrethroids (permethrin, S-fenvalerate and tetramethrin), led to the elimination of the mite population and resulted in normalization of most of the haematological and biochemical blood parameters (haemoglobin, erythrocytes, neutrophils, basophils, lymphocytes and AST). Increased eosinophils and ALT were the only indicators of infection in the blood of laying hens, and they remained above normal range until the 22nd day after the beginning of treatment with the acaricidal agent.

Staphylococcus aureusis an extremely infectious and malignant pathogen among many bacteria species. The aim of this work is to provide a robust classification model that would be able to identify S. aureusindependent of the culture growth stage and the variations in bacteria concentration in suspension and also one that would be able to identify the pathogen among both taxonomically close species of the same genus and taxonomically distant species of different genera, using Fourier transform infrared spectroscopy (FTIR). In total, the spectra of 141 isolates of 17 bacteria have been used. Based on a combination of principal component analysis (PCA) and linear discriminant analysis (LDA), an identification model providing 100% sensitivity and 98% specificity was built. Inherent reliability and flexibility of the model have been shown. The proposed method of analysis allows us to get closer to the diagnostic requirements in the field of clinical microbiology, and it can be utilized for typing of other pathogenic bacteria species.

The pLF1311 natural plasmid from Lactobacillus fermentum1311 was used to construct a single-replicon vector suitable for rapid cloning in a wide range of gram-positive hosts and Escherichia coli.The new vector is capable of conjugative mobilization from E. colito various hosts by conjugal transfer. The final vector (3.4 kb) showed a high segregational and structural stability and a high copy number. Glutamyl endopeptidase genes from Bacillus licheniformis(gseBL) and B. intermedius(gseBI) were cloned in both pLF9 and pLF14 vectors and introduced to B. subtilis.The yield of enzymes in the pLF-derived producers was 6- to 30-fold more than in the natural producers and reached 100–150 mg/L of mature protease.

A 15‐bp mini‐gene was introduced into Bacillus subtilisand into stable protoplast‐like L‐forms of Proteus mirabilis. This mini‐gene encoded the peptide MVLFV and modeled a fragment of Escherichia coli23S rRNA responsible for E. colierythromycin (Ery) resistance. Expression of the introduced mini‐gene conferred permanent Ery resistance on B. subtilis. In L‐forms of P. mirabilis, the Ery‐protective effect was maintained in the course of several generations. Herewith, the mechanism of Ery resistance mediated by expression of specific short peptides was shown to exist in evolutionary distant bacteria. Three new plasmids were constructed containing the gene under study transcriptionally fused with the genes encoding glutamylendopeptidase of Bacillus licheniformisor δ‐endotoxin of Bacillus thuringiensis. The Ery resistance pentapeptide (E‐peptide) mini‐gene served as an efficient direct transcriptional reporter and allowed to select bacillar glutamylendopeptidase with improved productivity. The mini‐genes encoding E‐peptides may be applied as selective markers to transform both Gram‐positive and Gram‐negative bacteria. The small size of the E‐peptide mini‐genes makes them attractive selective markers for vector construction.

A metalloprotease gene of Brevibacillus brevis(npr) was expressed in Escherichia coliin a soluble form as native Npr precursor. A significant fraction of the precursor was spontaneously processed, producing the N‐terminal propeptide and the mature enzyme. A strong inhibition of the mature Npr by its own propeptide in the crude lysate was observed even in the absence of the covalent linkage between them. Pure precursor, propeptide and the mature Npr were isolated and kinetic parameters of the mature enzyme inhibition by the propeptide were determined. The inhibition is of the tight‐binding competitive type with Ki0.17 nM. Inhibition of metalloproteases from Brevibacillus megateriumand thermolysine by the heterologous propeptide of the Npr from B. breviswas much weaker or none.

The glutamyl endopeptidase gene of Bacillus intermediuswas cloned from a genomic library expressed in Bacillus subtilisand sequenced (EMBL accession number Y15136). The encoded preproenzyme contains 303 amino acid residues; the mature 23-kDa enzyme consists of 215 residues. The mature enzyme reveals 38% of identical residues when aligned with the glutamyl endopeptidase from Bacillus licheniformis, whereas only five invariant residues were found among all known glutamyl endopeptidases. The amino acid residues that form the catalytic triad (H47, D98, and S171) as well as H186 participating in the binding of the substrate carboxyl group were identified. It seems that the structural elements responsible for the function of glutamyl endopeptidases from various sources are highly variable.

A 15-bp mini-gene was introduced into Bacillus subtilis and into stable protoplast-like L-forms of Proteus mirabilis. This mini-gene encoded the peptide MVLFV and modeled a fragment of Escherichia coli 23S rRNA responsible for E. coli erythromycin (Ery) resistance. Expression of the introduced mini-gene conferred permanent Ery resistance on B. subtilis. In L-forms of P. mirabilis, the Ery-protective effect was maintained in the course of several generations. Herewith, the mechanism of Ery resistance mediated by expression of specific short peptides was shown to exist in evolutionary distant bacteria. Three new plasmids were constructed containing the gene under study transcriptionally fused with the genes encoding glutamylendopeptidase of Bacillus licheniformis or δ-endotoxin of Bacillus thuringiensis. The Ery resistance pentapeptide (E-peptide) mini-gene served as an efficient direct transcriptional reporter and allowed to select bacillar glutamylendopeptidase with improved productivity. The mini-genes encoding E-peptides may be applied as selective markers to transform both Gram-positive and Gram-negative bacteria. The small size of the E-peptide mini-genes makes them attractive selective markers for vector construction.