UDP-galactose and UDP-glucose are the immediate sources of monosaccharide residues in glycosphingolipid biosynthesis. The incorporation of 6-3HD-galactose into these compounds was measured in primary ...cultures of rat hepatocytes, which take up and metabolize galactose rapidly. The UDP-glucose and UDP-galactose content of hepatocytes, determined enzymatically and by the HPLC-analysis of UDP-sugars, was 1.87 +/- 0.22 and 0.51 +/- 0.06 nmol/mg protein, respectively. Galactose concentrations in the medium of up to 7.5 microM did not influence the intracellular levels of UDP-glucose and UDP-galactose. Although the specific radioactivity of these precursor pools did not reach a constant plateau, conditions were defined that allow the calculation of rates of glycolipid synthesis from added labeled galactose. They include the replacement of glucose in the culture medium by sodium pyruvate and D-galactose.
Severe combined immunodeficiency disease (SCID) is an autosomal recessive trait affecting purebred and mixed breed Arabian horses. Similar diseases exist in humans, dogs and mice. First ...immunodeficiency with characteristics of SCID in Arabian horses was reported around 1960 in Australia. The disease was described as a syndrome in 1973. The disease prevents the production of functional lymphocytes in affected individuals, which leads to a complete loss of humoral and cellular immune response. The defect is a result of a genetic mutation (5 bp deletion) in a gene encoding DNA dependent protein kinase C (DNA-PKc). As SCID is recessive autosomal disease, clinical signs are present only in offspring from mating between two heterozygous carriers of the SCID mutation. Heterozygous carriers are asymptomatic, but can be detected by genetic testing. To identify the normal and mutant versions of the DNA-PKc gene, blood samples were collected from all Arabian horses in Slovenia and DNA extracted from the samples. The specific sequence of DNA-PKc including 5 bp deletion causing SCID was amplified using polymerase chain reaction (PCR) and the size of amplified DNA band was determined on a 4 % agarose gel. After successful amplification and interpretation of the DNA sequences, only negative results were found. We can therefore conclude that at present time there are no carriers of the mutation in DNA - PKc in Slovenia.
The aim of this research was to investigate the effect of growth phase and temperature on the concentrations of the individual molecular species of sphingoid bases obtained by acid hydrolysis of ...total sphingolipids from the yeast Yarrowia lipolytica. Our results showed C18 phytosphingosine to be the major long‐chain base in Y. lipolytica regardless of growth phase or temperature. We also found Y. lipolytica to contain sphingosine, the predominant mammalian long‐chain base that is uncommon for yeast sphingolipids. Among the identified long‐chain bases, only C18 phytosphingosine appeared to be influenced by culture conditions. Its concentration was largest in the exponential phase and decreased 2.9‐fold when cells entered the stationary phase of growth at 28 °C. Following a temperature shift from 28 to 39 °C, there was a 2.1‐fold decrease in the phytosphingosine concentration, but it rose 1.7‐fold after the heat‐stressed cells had been returned to 28 °C and subjected to prolonged growth. These results might point to the possible involvement of phytosphingosine in the cell growth regulation and in the adaptation of Y. lipolytica cells to stressful culture conditions.
Serological positive reaction to enzootic bovine leukosis (EBL) were established by means of agar- gel- imunodiffusion tests applied to 25 beef cattle. The pepsinogen activity in the ...serologically-positive sera was determined by using Paynters method. The results were compared with those from a group of 30 clinically healthy EBL negative young cattle and those from a group of 10 animals with pathoanatomical abomasal ulcers. Although not statistically significant, the mean pepsinogen activity in the sera of the EBL-positive beef cattle was higher (3.35 ± 2.31 U/L) than in the control group of EBL-negative animals (2.45 ± 1.00 U/L). The sera of the group of animals with abomasal ulcers had statistically significant higher mean value of pepsinogen (6.48 ± 1.80 U/L) than both the control and EBL-positive groups. A comparison of the established mean pepsinogen values confirmed that EBL-associated lymphosarcoma-related alternations on the abomasal mucosa were not manifested in the majority of the younger animals.
During the period 1991 - 2001, 161 cases of abomasum displacement were treated. Clinical and laboratory examinations, and later surgical intervention, revealed that 100 (62.1 %) cases were left-side ...displacements of the abomasum (LDA), 16 (9.9 %) were right-side displacements (RDA), 25 (15.5 %) cases involved torsion of the abomasum (AV) and 20 (12.4 %) were anterior displacements of the abomasum (ADA). In ADA the typical characteristics of the disease signs remain mild, unclear and variable, until the diagnosis is established. Over a half of the 20 affected cows (63.16 %) were between 7.5 to 9.0 months pregnant. Specific, high-pitched, tinkling sounds were detected in the left caudoventral, and right lateral, abdominal regions, just behind the limits of percussible lung area. There was no specific tympanitic resonance (ping effect) established with the percussion and simultaneous auscultation of the left abdomen, which included the left and right paralumbar fossa and an area extending from the midpoint of the 9th and 13th ribs. Rumination did not cease. Clinical signs were manifested by periparturient stubborn indigestion, loss of weight, relative absence of faeces and suboptimal milk production. Among laboratory findings ketonemia, mild haemoconcentration, slight hypochloraemia, hypokalaemia and hypocalcaemia were present. At the Clinic for Ruminants in Ljubljana, the surgical correction of all types of abomasal displacements is now commonly practised. On the basis of our experiences we have developed a method of omentopexy which is called the "Ljubljana method".
Sphingolipids have the potential to regulate cell behavior at essentially all levels of signal transduction. They serve as cell surface receptors for cytoskeletal proteins, immunoglobulins, and some ...bacteria; as modifiers of the properties of cell receptors for growth factors (and perhaps other agents); and as activators and inhibitors of protein kinases, ion transporters, and other proteins. the biological activity of these compounds resides not only in the more complex molecules, but also in their turnover products. Since sphingolipids change with cell growth, differentiation, and neoplastic transformation, they could be vital participants in the regulation of these processes.
Fumonisins are toxic metabolites of the fungus Fusarium moniliforme and several other Fusaria that commonly contaminate corn. Only recently discovered in 1988, these mycotoxins appear to be causative ...agents of several toxicoses in animals that result from ingestion of moldy corn and corn-based feeds. These include equine leukoencephalomalacia, porcine pulmonary oedema, nephrotoxicity, hepatotoxicity, hepatocarcinogenicity in laboratory animals. There is also evidence that suggests that F. moniliforme and fumonisins may also be responsible for oesophageal cancer in humans in certain areas of the world where moldy corn is frequently consumed. Fumonisins are structurally similar to sphingosine, and may exert their biological activity to block enzymes sphinganine- and sphingosine-N-acyl transferase involved in sphingolipid biosynthesis.
