The Effect of subsp. Infection on the Productivity of Cows in Two Dairy Herds with a Low Seroprevalence of Paratuberculosis.

Paratuberculosis is a chronic, progressive enteritis of ruminants, caused by subspecies . It affects the productivity of infected dairy cows, causing a reduction in the daily milk yield and basic milk components. The aim of the study was to determine the effect of subspecies on the productivity of dairy cows in two herds.

Examination of the chemical changes in cured phenol-formaldehyde resins during storage.

Chemical changes occurring within cured phenol-formaldehyde resins (resite and novolak type) during their storage were investigated by FT-NIR, py-GCMS and inverse gas chromatography. It was shown that a mixture of resite with novolak was less stable than resite or novolak itself as regards bulk properties. This aging phenomenon is mainly due to reaction of ammonia (product of hexa decomposition) with CH2OH groups present in resite.

Assessment of the chemical changes during storage of phenol-formaldehyde resins pyrolysis gas chromatography mass spectrometry, inverse gas chromatography and Fourier transform infra red methods.

The chemical changes occurring in the phenol-formaldehyde resins (resol and novolac type) during their storage were investigated. In this paper the FT-IR, py-GCMS and inverse gas chromatography methods were applied for assessment of the changes occurring during storage of the phenolic resins. We have found that during storage some examined resins occurred partial curing.

The YJL185C, YLR376C and YJR129C genes of Saccharomyces cerevisiae are probably involved in regulation of the glyoxylate cycle.

The ER24 aci (acidification) mutant of Saccharomyces cerevisiae excreting protons in the absence of glucose was transformed with a multicopy yeast DNA plasmid library. Three different DNA fragments restored the wild-type phenotype termed Aci- because it does not acidify the complete glucose medium under the tested conditions. Molecular dissection of the transforming DNA fragments identified two multicopy suppressor genes YJL185C, YJR129C and one allelic YLR376C.

The aminoesters as inhibitors of plasma membrane H+-ATPase in the yeast Saccharomyces cerevisiae.

A set of oxalates of alpha-dimethylamino fatty acids n-alkyl esters (MEM-ns and n-MEM-8s) and n-dodecyl-N,N-dimethylalaninate (DMAL-12s) were synthesized. Their activities on the growth, transport, and ATPases from the yeast Saccharomyces cerevisiae were compared. The compounds differ in the number of carbon atoms in their aliphatic chain and in the position of that chain in their molecular structure.

Acid excreting mutants of yeast Saccharomyces cerevisiae.

Saccharomyces cerevisiae mutants acidifying glucose medium containing bromocresol purple were shown to excrete protons when placed in unbuffered water in the absence of any external carbon source. The mutants belong to 16 different complementation groups. Most of them do not grow on glycerol and the excreted protons are associated to particular sets of organic anions such as citrate, aconitate, succinate, fumarate or malate.

Dicarboxylate platinum(II) complexes as inhibitors of plasma membrane H(+)-ATPase in the yeast Saccharomyces cerevisiae.

A series of cytotoxic neutral dicarboxylatoplatinum(II) complexes containing D(+), L(-) or DL-malate dianion and ethylenediamine or 1-ethylimidazole as ligands were examined using ATPase activity assays and the proton extrusion test. ATPase activity assays in vitro on plasma membrane H+-ATPase and on mitochondrial ATPase were carried out. The concentrations of compounds inhibiting enzyme activity to 50 per cent (J50) was determined.

The genetic characteristics Saccharomyces cerevisiae aci(+) mutants.

A series of 30 Saccharomyces cerevisiae aci(+) mutants (characterized as acidifying Ogur's glucose medium containing bromocresol purple) were isolated after EMS mutagenesis. All the mutants excreted acid metabolites to the medium after 24 or 48 hours of incubation. The character of the aci(+) mutations was defined using classical genetic techniques.

pH-dependent influence of a quaternary ammonium salt and an aminoester on the yeast Saccharomyces cerevisiae ultrastructure.

Quaternary ammonium salts inhibited the growth of yeast especially at pH higher (pH 8) than optimal. It was postulated that compounds integrate with the cell membrane and interfere with its functions. The yeast cell ultrastructure investigated under an electron microscope confirms this hypothesis.

Lysosomotropic N,N- dimethyl alpha-aminoacid N-alkyl esters and their quaternary ammonium salts as plasma membrane and mitochondrial ATPases inhibitors.

A set of n-alkyl esters of N,N-dimethylglycine (DMG-n) and their methobromides (DMGM-n) was synthesized, and their activities on yeast Saccharomyces cerevisiae were compared. The compounds differ in the number of carbon atoms in the aliphatic chain. Aminoesters with 12 carbon atoms appeared to be most active.

Comparative studies of the biological activities of lysosomotropic aminoesters and quaternary ammonium salts on the yeast Saccharomyces cerevisiae.

The biological activity of lysosomotropic n-alkyl N,N-dimethylglycinates (DMG-n) was compared with that of a quaternary ammonium salt IM (methochloride of DMG-12). The activity of the glycinates appeared to be carbon chain length dependent and was similar at pH 6 and pH 8. Nutritional auxotrophy and respiratory deficiencies have no influence on DMG-n sensitivity.

Studies of antibacterial activity of binuclear rhodium (II) complexes with heterocyclic nitrogen ligands.

Binuclear rhodium (II) complexes, [Rh2(OOCPh)2(phen)2(H2O)2] (OOCPh)2 (1), [Rh2(OOCPh)2(bpy)2(H2O)2] (OOCPh)2 (2), [Rh2(OOCBu(n))2 (bpy)2(H2O)2] (OOCBu(n)2 (3), and [Rh2(OOCPr(n)2 (phen)2(H2O)2] (OOCPr(n)2 (4) (Phen = 1,10-phenanthroline and bpy = 2,2'-bipyridine), have been synthesized and characterized using NMR, IR and electronic spectra. Activity of these compounds against Gram-positive bacteria decreases in the order: 1?2?3 > 4. Complex 1 is active against many Staphylococcus strains resistant to commonly used antibiotics.

Genetical and biochemical characterization of cycle Krebs mutant in yeast.

We present the results of genetical and biochemical investigations of yeast mutants which presumably are deficient in different steps of the Krebs cycle. The investigation of the activities of the Krebs cycle enzymes suggests that we have isolated two types of mutants: structural and regulatory.

Binuclear Rhodium(II) Complexes With Selective Antibacterial Activity.

Binuclear rhodium(II) complexes [Rh(2)Cl(2)(mu-OOCR)(2)(N-N)(2)] {R = H, Me; N-N = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen)} and [Rh(2)(mu-OOCR)(2)(N-N)(2)(H(2)O)(2)](RCOO)(2) (R = Me, Et;) have been synthesized and their structure and properties have been studied by electronic, IR and (1)H NMR spectroscopy. Antibacterial activity of these complexes against Escherichia coli and Staphylococcus aureus has been investigated. The most active antibacterial agents against E.

Properties of Binuclear Rhodium(II) Complexes and Their Antibacterial Activity.

Binuclear rhodium(II) complexes [Rh(2)Cl(2)(mu-OOCR)(2)(N-N)(2)], [Rh(2)(mu-OOCR)(2)(N-N)(2)(H(2)O)(2)](RCOO)(2) and [Rh(2)Cl(2)(mu-OOCCH(3))(terpy)(2)](H(3)O)Cl(2).9H(2)O (R = H, Me, Bu(n), ph, PhCHOH; N-N = 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (dmp) and 6,7-dimethyl-2,3- di(2-pyridyl)quinoxaline (dmpq); terpy 2,2':6',2''-terpyridine) have been synthesized and their structure and properties have been studied by electronic, IR and (1)H NMR spectroscopy. Antibacterial activity of these complexes against Staphylococcus aureus and Escherichia coli has been investigated.

[Bacterial antigenic structure of Shigella flexneri serotype 1B and its 3B serotype mutant and susceptibility to bacterial action of complement in normal bovine serum].

The susceptibility of S. flexneri 1b and 3b strains to killing action of serum was investigated. Differences in sensitivity to bactericidal action of complement appeared to result from different structure of their LPS-es.

Mechanism of antigenic variation in Shigella flexneri bacilli. III. Complement sensitivity of S. flexneri 1b strains and their 3b variants selected either as Lac+ recombinants or phage F2 resistant mutants.

Several S. flexneri 1b serotype strains of clinical isolation were compared with their 3b serotype variants isolated either as Lac+ recombinants from crosses of S. flexneri x E.

Population dynamics in the co-culture of Shigella flexneri 1b original strain and its antigenic 3b mutant carrying a prophage.

The antigenic mutant Shigella flexneri 3b showed selective prevalence when subcultured with the original strain 1b. Mathematical analysis of such co-cultures showed that the dynamics of bacterial growth may be described by equations of the Lotka-Volterra type. The analysis of serial cultivations suggests that parameters of the equations may be realizations of random variables characterizing strains and media.