N-3 Polyunsaturated Fatty Acids as a Nutritional Support of the Reproductive and Immune System of Cattle-A Review

This paper focuses on the role of n-3 fatty acids as a nutrient crucial to the proper functioning of reproductive and immune systems in cattle. Emphasis was placed on the connection between maternal and offspring immunity. The summarized results confirm the importance and beneficial effect of n-3 family fatty acids on ruminant organisms. Meanwhile, dietary n-3 fatty acids supplementation, especially during the critical first week for dairy cows experiencing their peripartum period, in general, is expected to enhance reproductive performance, and the impact of its supplementation appears to be dependent on body condition scores of cows during the drying period, the severity of the negative energy balance, and the amount of fat in the basic feed ration. An unbalanced, insufficient, or excessive fatty acid supplementation of cows' diets in the early stages of pregnancy (during fetus development) may affect both the metabolic and nutritional programming of the offspring. The presence of the polyunsaturated fatty acids of the n-3 family in the calves' ration affects not only the performance of calves but also the immune response, antioxidant status, and overall metabolism of the future adult cow.

Supplementation of Broiler Chicken Feed Mixtures with Micronised Oilseeds and the Effects on Nutrient Contents and Mineral Profiles of Meat and Some Organs, Carcass Composition Parameters, and Health Status

In this study, we included 15% doses of infrared-irradiated camelina, flax, and sunflower seeds in the diets of broiler chickens (grower and finisher) and focused on assessing the effects on the production traits, selected slaughter analysis parameters, nutrients, and minerals in breast and drumstick meat and some organs, i.e., liver, proventriculus, and heart. In total, 200 one-day-old broiler chickens were assigned randomly to four treatments with five replicate cages of 10 broiler chickens per cage (five females and five males). The experiment lasted 6 weeks. In the group of broiler chickens in which diets were supplemented with micronised camelina and flax seeds, there was an increase in (p < 0.05) breast, thigh, and drumstick weight and a decrease (p < 0.05) in the abdominal fat of the carcasses. The oilseed treatments reduced the ether extract content and the calorific value in the breast and drumstick muscles and organs. The flax seeds contributed to an increase in the contents of Ca (breast muscle and liver), Cu (breast muscle and proventriculus), and Fe (drumstick muscle and heart). Likewise, some blood parameters were influenced by supplementation with infrared-irradiated camelina and flax seeds, for example, there was a decrease in the haemoglobin level and the mean corpuscular haemoglobin concentration (p < 0.05). The oilseed treatments also modified the contents of Fe and Ca in the blood plasma of broiler chickens (p < 0.05). It may be concluded that infrared-irradiated camelina, flax, and sunflower seeds can be regarded as good diet components exerting positive effects on the dietary value of poultry meat and organs used in dietetics.

Influence of probiotic and yeast culture supplementation on selected biochemical and immunological parameters of growing lambs

This study was carried out to evaluate the potential effects of 90 days-long dietary supple- mentation of probiotic and yeast culture on immunity condition of lambs. Fifteen Rahmani growing male lambs (about 5 months old and 23.21±2.75 kg body weight) were randomly allo- cated to three equal groups consisting of 5 animals each. The animals in the first group, served as a control (group C), were fed a basal diet without any supplementation. The lambs in the second and third group were fed the basal diet supplemented with probiotic (group Y) or yeast culture (group YC), respectively. The probiotic consisted of live yeast (Saccharomyces cerevisae) alone, while the yeast culture was composed of Saccharomyces cerevisiae and the media on which it was grown. In group Y and YC, each lamb was supplemented daily with 0.5 g and 7.0 g of live yeast and yeast culture, respectively. Blood samples were collected before feeding the supplements and then every 15 days until the day 90th. Total and differential leucocytic counts, total protein, albumin, IgA, IgG and IgM levels were measured in blood. There were insignificant (p>0.05) variations in the levels of total and differential leucocytic counts and total protein among the groups throughout the experiment. However, significant differences (p⟨0.05) were found in globulin, IgA, IgG and IgM in both (Y) and (YC) groups, but the effect of yeast culture seems to be better than that of the probiotic. In conclusions, the obtained results indicate that the tested probiotic and yeast culture improve the immunological status of lambs.

The Protective Role of Alpha-Ketoglutaric Acid on the Growth and Bone Development of Experimentally Induced Perinatal Growth-Retarded Piglets

The effect of alpha-ketoglutaric acid (AKG) supplementation to experimentally-induced, perinatal growth-retarded piglets was examined. Sows were treated with a synthetic glucocorticoid (Gc) during the last 25 days of pregnancy, and after the birth, piglets were randomly divided into three groups depending on the treatment. The Gc/Gc + AKG and Gc/AKG groups born by Gc-treated sows after the birth were treated with Gc or Gc + AKG for 35 days. Significantly lower serum growth hormone, IGF-I, osteocalcin, leptin, and cortisol concentrations were observed in the Gc/Gc + AKG group, while the bone alkaline phosphatase activity was significantly higher. Serum insulin concentration was higher in the control group. Serum alanine, lysine, histidine, and tryptophan concentrations were higher in the Gc/Gc + AKG and Gc/AKG groups. The perinatal action of Gc significantly affects histomorphometry of articular cartilage and trabecular bone and bone mechanics. The results clearly showed that dietary AKG had positive effects with regards to the profile of free amino acids. Taking into account the function of AKG as an energy donor and stimulator of collagen synthesis, it can be concluded that the anabolic role of AKG may be the main mechanism responsible for its protective effect against the GC-induced perinatal intensified catabolic state.

Efficacy of β-hydroxy-β-methylbutyric acid (HMB) for growing rate and its influence for health indicators in blood test of young early-weaning goats

The study was conducted on 26 male, 30 days-old goats, separated from their mothers, divided into two equal groups: I - control and II - experimental, consisting of 13 animals each. All animals were fed with milk replacer, experimental group received additionally 50 g/kg body weight, additive of HMB, for 60 days. The following features were analyzed: body weight, daily increases of body weight, as well as hematological and biochemical blood features. Differences in body weight were found, between experimental and control group, after 60 days of experiment 0.57 kg (p≤0.01). The daily weight gain of experimental animals was higher in comparison with control group. Significant differences were also noted in results of hematological and biochemical blood parameters. Experimental animals showed a higher level of red blood cells as well as number of lymphocytes in comparison with the control group, (p≤0.01).Significant changes were also observed in the level of triglycerides, inorganic phosphorus and protein between both groups. The acid-base balance parameters and ionogram, showed a higher pH level (p≤0.05) HCO - act., HCO - std., BE, ctCO , O sat, K+, Cl- (p≤0.01), while the anion gap (AG) and Na+ were significantly lower in control group (p≤0.01).

A novel in vitro assay for assessing efficacy and toxicity of antifungals using human leukaemic cells infected with Candida albicans

AIMS

This study describes a novel in vitro assay that simultaneously determines antifungal efficiency and host cell toxicity using suspensions of human leukaemic cells (HL-60) infected with Candida albicans.

METHODS AND RESULTS

The effect of Candida infection on host cell viability was evaluated by the microscopy of trypan blue-stained cells and lactate dehydrogenase (LDH) activity. The in vitro 'drug potency assay' utilized the Cell Counting Kit-8 and measured post-antifungal treatment viability of Candida-infected HL-60 cells and the ability of the antifungal treatment to prevent infection. LDH activity showed that 42% ± 4·0 and 85·3% ± 7·40 of HL-60 cells were killed following Candida infection at the multiplicity of infection (MOI) of 1 : 1 and 1 : 5, respectively. The antifungal nystatin (0·78-25 μmol l(-1) ) was found to inhibit C. albicans infection as seen by the significantly increased viability of HL-60 cells. Cytotoxicity of nystatin towards infected HL-60 cells was evident at higher concentrations and this was also confirmed by propidium iodide staining.

CONCLUSIONS

An assay using undisturbed cell suspension conditions was successfully developed for assessing the selectivity of the antifungal therapy in the host-Candida environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

The assay employing Candida infection of host cell suspensions represents a promising method for testing interactions of antifungal compounds with both fungal and host cells.

Impact of <i>Saccharomyces cerevisiae</i> supplementation on reproductive performance, milk yield in ewes and offspring growth

Abstract. The effect of supplementing sheep diets with Saccharomyces cerevisiae Inter Yeast® dried brewer's yeast (Leiber GmbH, Bramsche, Germany) or with a Biolex® Beta-S (Leiber GmbH, Bramsche, Germany) extract containing over 70 % β-1,3/1,6-D-glucan was investigated. Experiment 1 was carried out with 120 ewes and 190 lambs. The animals were divided into three groups: I – control; II – fed yeast; and III – fed Biolex. The supplements were administered during a 3-week preparation period for tupping and a 70-day lamb-rearing period. The following reproductive parameters were analysed: fertility, prolificacy, lamb rearing and breeding performance, milk yield and lamb growth rate. Experiment 2 was conducted with 120 ewes divided into two groups: I – control and II – fed yeast during a 3-week preparation period. Fertility and prolificacy were analysed. Significant increases in prolificacy were recorded in sheep administered dried brewer's yeast: 28.51 % in experiment 1 and 31.33 % in experiment 2. Breeding performance was also higher by 35 %. Both yeast supplements had a stimulating impact on the milk yield of ewes and the growth rate of their offspring. Milk from the experimental ewes, especially in the group fed Biolex, had a substantially higher content of dry matter, mainly fat. The lambs in this group had the highest body weight at the age of 70 days. Finally, however, the production of livestock per mother was highest in the group fed the supplement with Saccharomyces cerevisiae.

Schlachtwert und Fleischqualität von Lämmern der Schafrasse Skudden

Abstract. Title of the paper: Slaughter value and meat quality of Skudde lambs The investigations were conducted on 100-day-old lambs of the Skudde breed and were aimed at determining the slaughter value of lambs and quality of their meat. The slaughter value was evaluated based on: body weight before slaughter, dressing percentage, loin »eye« area, perinephric fat content, contribution of valuable cuts in the carcass (leg, loin, steak) and tissue composition of legs. In turn, meat quality was assessed based on samples collected from the muscle of the thigh (M. quadriceps femoris) and included: dry matter, total protein, crude fat, crude ash, pH after 24 h, water/protein index, energy value, water holding capacity, colour brightness, muscle fibre diameter, levels of cholesterol, vitamin A and E, protein amino acid profile, fatty acid composition of intramuscular fat, as well as sensory attributes, namely: aroma, taste, juiciness and tenderness. Analyses conducted in the study demonstrated that the slaughter value of the lambs was at a relatively good level. A low body weight before slaughter (12.56 kg) was compensated for by very low adiposity of carcasses and by a favourable tissue composition of legs, i.e. 76.38 % of meat, 5.68 % of fat and 17.94 % of bones. Dressing percentage accounted for 44.03 %, and the percentage of primal cuts in the half-carcass was 38.77 %. Meat of the 100-day-old Skudde lambs was found to be of high quality. It was characterized by dark colour and specific sensory attributes, which makes it comparable to game meat. Low contents of fat – 1.56 % and cholesterol – 34.47 mg/100g, a high concentration of vitamin A – 5.25 μg/g as well as a favourable fatty acid profile of intramuscular fat indicate high health-promoting values of that meat. In addition, the finefibrous structure of muscles (fibre diameter of 17.24 μm) suggests that the meat is light and easy digestible. The results obtained in the study substantiate the advisability of a wider application of this breed for meat production purposes.

Immunomodulating effect of Inter Yeast S on the non-specific and specific cellular and humoral immunity in lambs

The objective of this study was to determine the stimulating effect of the Inter Yeast S dietary supplement on selected parameters of specific and non-specific humoral and cellular immunity in lambs. The study involved 32 lambs aged 30 +/- 3 days, divided into two equal groups: II--control, and II--experimental. Experimental group animals were fed a C-J concentrate mixed with a prebiotic, the Inter Yeast S, commercially available, containing dried brewer's yeast Saccharomyces cerevisiae in the amount of 3 g/kg of the concentrate. At the beginning of the experiment (day 0) and on the 15th, 30th and 60th day of the study, blood was sampled from the jugular vein to determine selected parameters of biochemical, specific and non-specific humoral and cellular immunity in lambs (total protein levels, gamma globulin levels, lysozyme activity, ceruloplasmin activity, proliferative response of blood lymphocytes (MTT) after stimulation with LPS or ConA, the metabolic activity (RBA) and potential killing activity (PKA) of phagocytes). As regards humoral immunity parameters, significantly higher gamma globulin levels and higher lysozyme and ceruloplasmin activity were found in blood serum of experimental lambs administered the Inter Yeast S, compared with those determined in control lambs not fed the supplement. No statistically significant differences in serum total protein were found between the control and experimental groups. An analysis of cellular immunity indicators revealed significantly higher levels of RBA and PKA, and higher proliferative response of blood lymphocytes (MTT) after stimulation with LPS and ConA in the experimental group, compared with those observed in the control group.

Composition and properties of meat of Pomeranian purebred lambs and their crossbreeds with Berrichon du Cher and Charolaise

Abstract. The quality characteristics of meat from 50-day-old Pomeranian lambs (PP) and crossbreeds by Berrichon du Cher (PB) and Charolaise (PCH) rams were determined in the study. Samples of the quadriceps muscle of the tight (m. quadriceps femoris) were taken to determine the chemical composition, physicochemical and healthful properties of meat, such as energy value, concentrations of cholesterol and collagen and the fatty acid profile in intramuscular fat. A sensory evaluation of lamb and texture measurement were also performed. It was found that both sire breeds had a significant effect on meat quality. Meat from crossbreds contained more dry matter and protein, and was characterized by a more desirable W/P ratio, a lower calorific value, a lower collagen content and better texture parameters. Crossing had no considerable influence on the fatty acid composition in intramuscular fat, but caused changes in the cholesterol content of meat, which decreased in PB lambs and increased in PCH lambs. Taking into account the health benefits and culinary values of lamb, Berrichon du Cher is a preferred sire breed.

ABC transporters Cdr1p, Cdr2p and Cdr3p of a human pathogen Candida albicans are general phospholipid translocators

We have used fluorescent 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD)-tagged phospholipid analogues, NBD-PE (phosphatidylethanolamine), NBD-PC (phosphatidylcholine) and NBD-PS (phosphatidylserine), to demonstrate that Cdr1p and its other homologues, Cdr2p and Cdr3p, belonging to the ATP-binding cassette (ABC) superfamily behave as general phospholipid translocators. Interestingly, CDR1 and CDR2, whose overexpression leads to azole resistance in C. albicans, elicit in-to-out transbilayer phospholipid movement, while CDR3, which is not involved in drug resistance, carries out-to-in translocation of phospholipids between the two monolayers of plasma membrane. Cdr1p, Cdr2p and Cdr3p could be further distinguished on the basis of their sensitivities to different inhibitors. For example, the in-to-out activity associated with Cdr1p and Cdr2p is energy-dependent and sensitive to sulphydryl blocking agents such as N-ethylmaleimide (NEM) and cytoskeleton disrupting agent cytochalasin E, while Cdr3p-associated out-to-in activity is energy-dependent but insensitive to NEM and cytochalasin E. We found that certain drugs, such as fluconazole, cycloheximide and miconazole, to which Cdr1p confers resistance could also affect in-to-out transbilayer movement of NBD-PE, while the same drugs had no effect on Cdr3p-mediated out-to-in translocation of NBD-PE. The ineffectiveness of these drugs to affect Cdr3p mediated out-to-in phospholipid translocation further confirms the inherent difference in the directionality of phospholipid translocation between these pumps. Notwithstanding the role of some of the Cdrps in drug resistance, this study clearly demonstrates that these ABC transporters of C. albicans are phospholipid translocators and this function could represent one of the physiological functions of such large family of proteins.

Mechanism of antifungal action of kanosamine

The antibiotic kanosamine inhibited growth of Saccharomyces cerevisiae and a range of human pathogenic fungi, including Candida albicans. Kanosamine was transported into C. albicans cells by the glucose transport system and subsequently phosphorylated. The product of its intracellular metabolism, kanosamine-6-phosphate, was an inhibitor of the enzyme glucosamine-6-phosphate synthase. Inhibition was competitive in respect to one of the substrates, D-fructose-6-phosphate, with Ki = 5.9 mM, and was non-competitive in respect to the second substrate, L-glutamine. On the other hand, kanosamine-6-phosphate had no effect on the enzyme catalysing the next metabolic step, namely glucosamine-6-phosphate N-acetylase. The action of kanosamine on C. albicans cells resulted in profound morphological changes, inhibition of septum formation and cell agglutination. Experiments with S. cerevisiae mutants showed that the presence of the Cdr1p drug efflux pump did not affect the antifungal activity of kanosamine.

Amide and ester derivatives of N3-(4-methoxyfumaroyl)-(S)-2,3-diaminopropanoic acid

Several amide and ester derivatives of a glutamine analogue, N3-(4-methoxyfumaroyl)-(S)-2,3-diaminopropanoic acid (FMDP) (1-8), were synthesized and evaluated for the inhibitory activity in regard to glucosamine-6-phosphate synthase from Candida albicans. The syntheses were accomplished by the reaction of N2-tert-butoxycarbonyl-N3-(4-methoxyfumaroyl)-(S)-2,3-diaminopropanoic acid (BocFMDP) with the corresponding amines to give the FMDP amides (1-4) or with alkyl halides to give corresponding esters of FMDP (5-8). Among the synthesized compounds, the acetoxymethyl ester of FMDP was the most active inhibitor of the enzyme. Its IC50 value compared to that of FMDP (4 microM) was equal to 11.5 microM. The methyl and allyl esters and the N-hexyl-N-methyl-amide of FMDP exhibited a moderate enzyme inhibitory activity.

Unusual susceptibility of a multidrug-resistant yeast strain to peptidic antifungals

The susceptibility of Saccharomyces cerevisiae JG436 multidrug transporter deletion mutant, Deltapdr5, to several antifungal agents was compared to that of JG436-derived JGCDR1 and JGCaMDR1 transformants, harboring the CDR1 and CaMDR1 genes, encoding the main drug-extruding membrane proteins of Candida albicans. The JGCDR1 and JGCaMDR1 yeasts demonstrated markedly diminished susceptibility to the azole antifungals, terbinafine and cycloheximide, while that to amphotericin B was unchanged. Surprisingly, JGCDR1 but not JGCaMDR1 cells showed enhanced susceptibility to peptidic antifungals, rationally designed compounds containing inhibitors of glucosamine-6-phosphate synthase. It was found that these antifungal oligopeptides, as well as model oligopeptides built of proteinogenic amino acids, were not effluxed from JGCDR1 cells. Moreover, they were taken up by these cells at rates two to three times higher than by JG436. The tested oligopeptides were rapidly cleaved to constitutive amino acids by cytoplasmic peptidases. Studies on the mechanism of the observed phenomenon suggested that an additive proton motive force generated by Cdr1p stimulated uptake of oligopeptides into JGCDR1 cells, thus giving rise to the higher antifungal activity of FMDP [N(3)-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid]-peptides.

Purification to homogeneity of Candida albicans glucosamine-6-phosphate synthase overexpressed in Escherichia coli

The Candida albicans GFA1 gene encoding glucosamine-6-phosphate synthase, an enzyme of cell wall biosynthesis pathway in fungi and bacteria, recently an object of interest as a target for the chemotherapy of systemic mycoses, was PCR amplified and cloned to an Escherichia coli expression vector pET23b. The activity of the enzyme in the lysates from the overproducing E. coli strain was approximately 50-100 times higher than in the lysates from the control E. coli strain. This abundant overproduction allows to purify milligram amounts of the enzyme to homogeneity.

Oligomeric structure and regulation of Candida albicans glucosamine-6-phosphate synthase

Candida albicans glucosamine-6-phosphate (GlcN-6-P) synthase was purified to apparent homogeneity with 52% yield from recombinant yeast YRSC-65 cells efficiently overexpressing the GFA1 gene. The pure enzyme exhibited Km(Gln) = 1.56 mM and Km(Fru-6-P) = 1.41 mM and catalyzed GlcN-6-P formation with kcat = 1150 min-1. The isoelectric point of 4.6 +/- 0.05 was estimated from isoelectric chromatofocusing. Gel filtration, native polyacrylamide gel electrophoresis, subunit cross-linking, and SDS-polyacrylamide gel electrophoresis showed that the native enzyme was a homotetramer of 79.5-kDa subunits, with an apparent molecular mass of 330-340 kDa. Results of chemical modification of the enzyme by group-specific reagents established an essential role of a cysteinyl residue at the glutamine-binding site and histidyl, lysyl, arginyl, and tyrosyl moieties at the Fru-6-P-binding site. GlcN-6-P synthase in crude extract was effectively inhibited by UDP-GlcNAc (IC50 = 0.67 mM). Purification of the enzyme markedly decreased the sensitivity to the inhibitor, but this could be restored by addition of another effector, glucose 6-phosphate. Binding of UDP-GlcNAc to the pure enzyme in the presence of Glc-6-P showed strong negative cooperativity, with nH = 0.54, whereas in the absence of this sugar phosphate no cooperative effect was observed. Pure enzyme was a substrate for cAMP-dependent protein kinase, the action of which led to the substantial increase of GlcN-6-P synthase activity, correlated with an extent of protein phosphorylation. The maximal level of activity was observed for the enzyme molecules containing 1. 21 +/- 0.08 mol of phosphate/mol of GlcN-6-P synthase. Monitoring of GlcN-6-P synthase activity and its sensitivity to UDP-GlcNAc during yeast --> mycelia transformation of C. albicans cells, under in situ conditions, revealed a marked increase of the former and a substantial fall of the latter.

Cloning and sequence analysis of Histoplasma capsulatum glucosamine-6-phosphate synthase gene fragment

The 3' part of the glucosamine-6-phosphate synthase gene from Histoplasma capsulatum was PCR amplified using degenerate primers designed from the known glucosamine-6-phosphate synthase gene sequences, cloned and sequenced. The computer analysis of the 676 bp sequence revealed the presence of two introns. The identities of the deduced amino acid sequence to the corresponding Saccharomyces cerevisiae and Candida albicans fragment are 65 and 63.8%, respectively.

Antihistoplasmal in vitro and in vivo effect of Lys-Nva-FMDP

The new synthetic antifungal agent, L-Lysyl-L-Norvalyl-FMDP, inhibits growth of the yeast form of Histoplasma capsulatum. The compound is transported into the fungal cells by peptide permeases, cleaved intracellularly to constitutive amino acids, and the released C-terminal amino acid inhibits glucosamine-6-phosphate synthase. Promising antihistoplasmal in vivo activity of the FMDP-peptide was observed in an organ load test in mice.

Isolation and characterization of the GFA1 gene encoding the glutamine:fructose-6-phosphate amidotransferase of Candida albicans

Glutamine:fructose-6-phosphate amidotransferase (glucosamine-6-phosphate synthase) catalyzes the first step of the hexosamine pathway required for the biosynthesis of cell wall precursors. The Candida albicans GFA1 gene was cloned by complementing a gfa1 mutation of Saccharomyces cerevisiae (previously known as gcn1-1; W. L. Whelan and C. E. Ballou, J. Bacteriol. 124:1545-1557, 1975). GFA1 encodes a predicted protein of 713 amino acids and is homologous to the corresponding gene from S. cerevisiae (72% identity at the nucleotide sequence level) as well as to the genes encoding glucosamine-6-phosphate synthases in bacteria and vertebrates. In cell extracts, the C. albicans enzyme was 4-fold more sensitive than the S. cerevisiae enzyme to UDP-N-acetylglucosamine (an inhibitor of the mammalian enzyme) and 2.5-fold more sensitive to N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (a glutamine analog and specific inhibitor of glucosamine-6-phosphate synthase). Cell extracts from the S. cerevisiae gfa1 strain transformed with the C. albicans GFA1 gene exhibited sensitivities to glucosamine-6-phosphate synthase inhibitors that were similar to those shown by the C. albicans enzyme. Southern hybridization indicated that a single GFA1 locus exists in the C. albicans genome. Quantitative Northern (RNA) analysis showed that the expression of GFA1 in C. albicans is regulated during growth: maximum mRNA levels were detected during early log phase. GFA1 mRNA levels increased following induction of the yeast-to-hyphal-form transition, but this was a response to fresh medium rather than to the morphological change.

Amide and ester derivatives of N3-trans-epoxysuccinoyl-L-2,3-diaminopropanoic acid: inhibitors of glucosamine-6-phosphate synthase

Several analogs 5, 6, 7, 8, 10 and 11 of the C-terminal fragment of a peptide antibiotic Sch 37137 were designed and tested as inhibitors of glucosamine-6-phosphate synthase from Saccharomyces cerevisiae. From IC50 values and kinetic parameters of inhibition of glucosamine-6-phosphate synthase by compounds 5-11 it has been found that the inhibitory potency of these compounds follows the order: 6 > 5 > 8 > 9 > 7, 10, 11. This suggests that an inhibitor with a primary amido group binds better to the active site of the enzyme than other inhibitors. The order of reactivity of compounds 5-11 may be attributed to a steric inability of the inhibitor to fit into the active site of the enzyme and also indicates the importance of the chirality of trans-epoxysuccinic acid on the inhibitory properties of the synthesized compounds.

The influence of the reproductive cycle on levels of some metabolism indices in ewes

Investigations were performed in 14 ewes of the Polish Merino race, undergoing the second reproductive cycle. Fundamental indices of the protein and energy metabolism, levels of Ca, P, Mg, Cu, Fe and beta-carotene as well as vitamins A, E and C in the blood plasma and serum were determined. The analyses were carried out during the following periods of the reproductive cycle: 3 weeks before mating, the early and late pregnancy, the culmination and close of lactation. The levels of metabolism indices, especially those of the protein and energy metabolism, were found to vary during the studied periods of the reproductive cycle. In all the periods, low levels (during lactation a deficiency) of Ca and Mg and a distinct deficiency of vitamin C were detected. It seems therefore, necessary to work out the reference values for particular periods of the reproductive cycle.

[About fluorescein angiography one more time]

The authors remind commonly known values of fluorescein angiography, techniques of its performance and the scheme of preparation of the photographic material for adequate evaluation, description and preservation.

Chemical modification studies of the active site of glucosamine-6-phosphate synthase from baker's yeast

Glucosamine-6-phosphate synthase from baker's yeast has been purified 100-fold with a final recovery of 70%. The purification procedure involved thiol-affinity chromatography. Chemical modification studies of the enzyme revealed the presence of cysteine, Glu/Asp-carboxyl and probably histidine at the glutamine binding site and, on the other hand, arginine and probably another histidine at the D-fructose 6-phosphate binding site. A few glutamine analogs, including 6-diazo-5-oxo-L-norleucine (DON), anticapsin and N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), were shown to inactivate the enzyme in a time- and concentration-dependent manner. Anticapsin, the most active in the series, exhibited an inactivation constant, Kinact, of 9.5.10(-6) M.

Chemical modification studies of the active centre of Candida albicans chitinase and its inhibition by allosamidin

Allosamidin, a glycoside antibiotic, is shown to be a strong, competitive inhibitor of semi-purified chitinase from yeast cells of Candida albicans. The inhibitory potency of allosamidin was pH-dependent, with IC50 values of 280 nM at pH 5.0 and 21 nM at pH 7.5. At higher, micromolar, concentrations, allosamidin inactivated this chitinase in a time- and concentration-dependent manner. Kinetic studies of this inactivation provided evidence for the formation of a reversible complex between allosamidin and chitinase, characterized by Kinact = 5 microM, followed by irreversible modification of the enzyme with velocity constant k2 = 4.6 x 10(-3) s-1. Chemical modification studies with the use of group-specific reagents suggested the presence of Glu/Asp carboxyl group(s) at or near the active site, that were important for enzyme activity. The carboxyl-specific reagent, 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide, inactivated the chitinase in a single step process, with apparent second-order rate constant of 0.014 M-1 s-1.

The influence of serum proteins on biological activity of anticandidal peptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid

The binding of several anticandidal peptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) to serum proteins was studied using equilibrium dialysis. The affinity of these FMDP-peptides for serum albumin was low and well correlated with their biological activity against Candica albicans ATCC 26278 in serum albumin solution. This binding did not affect the biological activity of FMDP-peptides. On the other hand, substantial raising of MIC values was observed when anticandidal activity of FMDP peptides was assayed in the presence of complete serum proteins. This effect was likely to be a result of interaction with non-albumin components of serum proteins. Preliminary evidence points to the possibility of non-specific interaction with components containing sulfhydryl groups. In this study Nva-FMDP-Nva peptide was shown to be the most active compound in the serum protein solution. Moreover Nva-FMDP-Nva was most resistant to inactivation by serum components in comparison to other FMDP-peptides.

N3-haloacetyl derivatives of L-2,3-diaminopropanoic acid: novel inactivators of glucosamine-6-phosphate synthase

N3-Haloacetyl derivatives of L-2,3-diaminopropanoic acid, novel glutamine analogs, were shown to be strong inhibitors of glucosamine-6-phosphate synthase from bacteria and Candida albicans. The inhibition was competitive with respect to glutamine and non-competitive with respect to D-fructose-6-phosphate. In the absence of glutamine, the tested compounds inactivated glucosamine-6-phosphate synthase from C. albicans with Kinact = 0.5 microM, 0.55 microM and 18.5 microM for bromoacetyl-, iodoacetyl- and chloroacetyl derivatives of L-2,3-diaminopropanoic acid, respectively. The inactivation obeyed the criteria for active site-directed modification.

Synergistic action of nikkomycin X/Z with azole antifungals on Candida albicans

Fluconazole, ketoconazole and tioconazole were shown to act synergistically in vitro with the antibiotic nikkomycin X/Z on the pathogenic fungus Candida albicans. The phenomenon was demonstrated using a checkerboard technique and growth inhibition experiments. The azole antifungal agents, even at concentrations not affecting growth, decreased the incorporation of the 14C-label from [14C]glucose into chitin of the candidal cell wall. After 3 h incubation with tioconazole, 1 microgram ml-1, the incorporation of the radiolabelled glucose into chitin of intact cells and regenerating spheroplasts of C. albicans was inhibited by 43% and 30%, respectively. Moreover, the relative chitin content was approximately 45% lower than that of control cells. The chitin content increased after prolonged incubation with azoles, thus confirming the known phenomenon of azole-induced uncoordinated chitin synthesis and deposition. On the other hand, azole derivatives had very little effect on the rate of nikkomycin transport into C. albicans cells. A sequential blockade mechanism of synergism is proposed.

Mechanism of action of anticandidal dipeptides containing inhibitors of glucosamine-6-phosphate synthase

The mechanism of anticandidal action of novel synthetic dipeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) residues was shown to be consistent with the "warhead delivery" concept. FMDP dipeptides were shown to be transported into Candida albicans cells by the di-tripeptide permease and subsequently hydrolyzed by intracellular peptidases, especially aminopeptidase. The anticandidal activity of the particular FMDP dipeptide was influenced by the rate of its transport and, to a lower extent, by the intracellular cleavage rate. A high transport rate accompanied by a high cleavage rate resulted in the high anticandidal activity of L-norvalyl-FMDP. The strong growth-inhibitory effect of this compound was the consequence of inhibition of the enzyme glucosamine-6-phosphate synthase by the released FMDP. The action of L-norvalyl-FMDP on exponentially growing C. albicans cells resulted in a sharp decrease of incorporation of 14C label from [14C]glucose into chitin, mannoprotein, and glucan. This effect, as well as the growth-inhibitory effect, was fully reversed by exogenous N-acetyl-D-glucosamine. Glucosamine-6-phosphate synthase was proved to be the only essential target for FMDP dipeptides. Scanning electron microscopy of C. albicans cells treated with L-norvalyl-FMDP revealed highly distorted, wrinkled, and collapsed forms. Cells formed long, bulbous chains, and partial lysis occurred.

Antimicrobial properties of N3-(iodoacetyl)-L-2,3-diaminopropanoic acid-peptide conjugates

Six peptide conjugates consisting of either norvaline, methionine, or lysine and N3-(iodoacetyl)-L-2,3-diaminopropanoic acid--a strong, irreversible inactivator of bacterial and fungal glucosamine-6-phosphate synthase--were synthesized and their antibacterial and antifungal activities were evaluated. Antimicrobial potencies of these peptides were correlated with their transport and cleavage rates inside the cells. Bacteriolysis of Bacillus pumilus cells and inhibition of [14C]glucose incorporation into cell-wall polysaccharides of Candida albicans as a result of glucosamine 6-phosphate inactivation were also observed. Reversal of growth inhibitory effect of these peptides by N-acetylglucosamine in bacteria and fungi suggests the effective delivery of N3-iodoacetyl-L-2,3-diaminopropanoic acid into the cell by a peptide-transport system.

Anticandidal properties of N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid oligopeptides

Tri-, tetra-, and pentapeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), an inactivator of glucosamine 6-phosphate synthase of fungal origin (a key enzyme in the biosynthesis of macromolecular components of the fungal cell wall) have been synthesized and investigated as anticandidal agents. Structure-activity relationships of a series of peptides revealed that tripeptides were generally more active than the other peptides examined. In this study, the lysyl peptide, Lys-Nva-FMDP has been found to be the most active compound in the series.

[Polymyositis in pulmonary tuberculosis]

A case in reported of the clinical syndrome of polymyositis in a young man. The syndrome masked pulmonary tuberculosis. Sudden appearance of pains and weakness of the muscles of the shoulder and abdominal muscles was accompanied by fever up to 40 degrees C, and macular rash on the trunk and extremities. During the disease right-sided pneumonia developed and regressed after treatment with antibiotics (tetracyclines, penicillin). Laboratory investigations showed high ESR, high leucocyte count, high levels of transaminases, CPK and LDH, and in cutaneo-muscular++ biopsy specimen scan subepidermal infiltrations were present. The patient was treated with corticosteroids with a striking improvement of the general condition. During this treatment left-sided pleural effusion developed. Bacteriological examination of the pleural fluid, including tests for acid-fast bacilli, was negative in direct examination, but these bacilli were cultured from fluid. No malignant cells were found. After antituberculous treatment the condition of the patient and the biochemical parameters became normal.

Synthesis and biological properties of N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid dipeptides, a novel group of antimicrobial agents

A series of dipeptides with N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP), the irreversible inhibitor of glucosamine-6-phosphate synthetase from bacteria and fungi, have been synthesized and their antibacterial and antifungal properties in vitro evaluated. The results demonstrate that these peptides inhibit the growth of a number of the tested microorganisms, especially pathogenic fungus Candida albicans. The results of competitive antagonism studies indicate specific peptide transport of the peptides via peptide permeases as drug delivery system and gives evidence for the high selectivity of the action upon the cells, as a result of the inhibition of generation of glucosamine.

Antibiotic tetaine--a selective inhibitor of chitin and mannoprotein biosynthesis in Candida albicans

The antibiotic tetaine inhibits in Candida albicans the biosynthesis of two important cell wall constituents, chitin and mannoprotein. This effect is a consequence of inactivation of the enzyme glucosamine-6-phosphate synthetase. Due to the lack of glucosamine-6-phosphate the effective secretion of mannoprotein enzymes, acid phosphatase and invertase, by Candida albicans spheroplasts is inhibited. In the presence of tetaine, probably a modified mannoprotein, lacking a branched polymannan, is synthesized. The antibiotic action decreases the viability of Candida albicans cells, especially that of mycelial forms of this fungus.

Synthesis of N3-fumaramoyl-L-2,3-diaminopropanoic acid analogues, the irreversible inhibitors of glucosamine synthetase

Several analogues of N3-fumaramoyl-L-2,3-diaminopropanoic acid were synthesized and evaluated for inhibition of glucosamine-6-phosphate synthetase activity. The syntheses were accomplished by acylation reaction of N2-tert.-butoxycarbonyl-L-2,3-diaminopropanoic acid (Boc-A2pr) or N2-tert.-butoxycarbonyl-L-2,4-diaminobutanoic acid (Boc-A2-bu) with the N-succinimidoyl esters of several derivatives of alpha, beta-unsaturated acids 2a-d followed by deprotection of the Boc groups. The obtained compounds were tested for inhibition of glucosamine synthetase isolated from Salmonella typhimurium and Saccharomyces cerevisiae. The results indicated that among the synthesized compounds, N3-4-methoxyfumaroyl-L-2,3-diaminopropanoic acid (FMDP) was the most powerful inhibitor of glucosamine synthetase.

Femoral artery laceration complicating an intertrochanteric hip fracture: a multi-disciplinary therapeutic problem

Major arterial injuries are uncommon complications of intertrochanteric hip fractures. Described is transcatheter embolization of a lacerated femoral artery complicated by a large hematoma, discovered following surgical repair of an eight day old intertrochanteric fracture. The case was complicated due to a history of aspirin usage, marked obesity, and thrombocytopenia. Interventional radiology techniques may provide an alternative to surgery in selected cases.

Synthetic derivatives of N3-fumaroyl-L-2,3-diaminopropanoic acid inactivate glucosamine synthetase from Candida albicans

Synthetic derivatives of N3-fumaroyl-L-2,3-diaminopropanoic acid constitute the novel group of glutamine analogs. They are powerful, competitive inhibitors of the glucosamine synthetase (2-amino-2-deoxy-D-glucose-6-phosphate ketol-isomerase (amino-transferring), EC 5.3.1.19) from Candida albicans with respect to glutamine and uncompetitive with respect to D-fructose 6-phosphate. Some of the compounds tested irreversibly inactivate glucosamine synthetase with Kinact values of 10(-4) to 10(-6) M. The addition of glutamine protects enzyme from the inactivation, while the absence of D-fructose 6-phosphate lowers the rate of inactivation. An ordered, sequential mechanism is suggested for binding of the inhibitors to the glutamine-binding site. A number of tested compounds act as active-site-directed, irreversible inhibitors. It is suggested that derivatives of N3-fumaroyl-L-2,3-diaminopropanoic acid should be classified as mechanism-based enzyme inactivators. Structural requirements for an effective inactivator containing N3-fumaroyl-L-2,3-diaminopropanoic acid moiety are discussed.

Inhibition of glucosamine-6-phosphate synthetase from bacteria by anticapsin

On the basis of kinetic studies on glucosamine-6-phosphate synthetase (EC 5.3.1.19) from six bacteria sources it has been shown that the epoxyamino acid anticapsin, a glutamine analog, is a competitive inhibitor of the enzyme in regard to glutamine with Km value of 10(-4) M and Ki varying from 10(-7) to 10(-6) M. Unlike other glutamine analogs like 6-diazo-5-oxo-L-norleucine, chloropentanoic acid, L-alpha-amino-3-chloro-4,5-dihydro-5-isoxazole acetic acid or albizziin, anticapsin is not generally inhibitory to various amidotransferases. It does not inhibit xanthosine 5'-monophosphate amidotransferase, glutaminase or gamma-glutamyltranspeptidase.

Growth inhibitory effect of antibiotic tetaine on yeast and mycelial forms of Candida albicans

The mycelial (M) form of Candida albicans is more sensitive to the action of the antibiotic tetaine than the yeast (Y) form. Tetaine, at low concentrations about 1 microgram/ml also inhibits Y-M transition. It causes severe deformation of cells, agglutination and inhibits septum formation in the yeast forms. Tetaine action is reversed by dipeptides in both forms and by tripeptides in M form. N-acetyl glucosamine is a powerful antagonist of tetaine action on both morphological forms. Tetaine action on mycelial forms is slightly antagonised by N-acetyl mannosamine and very powerfully by glutamine.