scholarly journals Changes in a-Lactalbumin, Total Lactose, UDP-Galactose Hydrolase and other Factors in Tammar Wallaby (Macropus eugenii) Milk during Lactation

1987 ◽  
Vol 40 (1) ◽  
pp. 37 ◽  
Author(s):  
MichaeI Messer ◽  
Christine Elliott
Keyword(s):  
Post Partum ◽  
Rabbit Antiserum ◽  
Tammar Wallaby ◽  
Macropus Eugenii ◽  
Milk Samples ◽  
In Vitro Hydrolysis ◽  
Nucleotide Pyrophosphatase ◽  
Hydrolysis Of

a-Lactalbumin was isolated from milk of M. eugenii and its concentration in milk samples taken at various times during lactation (0-40 we.eks post partum) was determined by single radial immunodiffusion using rabbit antiserum to the purified protein. The a-lactalbumin concentration remained almost constant throughout lactation even though the concentration of total lactose (free �lactose plus lactose contained in oligosaccharides) feli to zero after 34 weeks post partum. This fall in lactose was accompanied by a rise in the free galactose and glucose concentrations and marked increases in UDPgalactose hydrolase, nucleotide pyrophosphatase, alkaline phosphatase and acid fj-galactosidase activities. It is suggested that the in vitro hydrolysis of UDP-galactose was due to nucleotide pyrophosphatase and that this enzyme may also playa role in vivo late in lactation by making UDP-galactose unavailable for the synthesis of lactose. Alternatively, lactose and lactose-containing oligosaccharides might be degraded by the acid fj-galactosidase during or after secretion.

Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia)

1992 ◽  
Vol 4 (5) ◽  
pp. 533 ◽  
Author(s):  
G Chaturapanich ◽  
RC Jones ◽  
J Clulow
Keyword(s):  
Protein Synthesis ◽  
Protein Secretion ◽  
Tammar Wallaby ◽  
Secreted Proteins ◽  
Blood Proteins ◽  
Macropus Eugenii ◽  
Cauda Epididymidis

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.

Changes in milk carbohydrates during lactation in the common brushtail possum, Trichosurus vulpecula (Marsupialia:Phalangeridae)

1989 ◽  
Vol 1 (4) ◽  
pp. 309 ◽  
Author(s):  
EA Crisp ◽  
PE Cowan ◽  
M Messer
Keyword(s):  
Tammar Wallaby ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Macropus Eugenii ◽  
Qualitative And Quantitative ◽  
Milk Samples ◽  
Nucleotide Pyrophosphatase ◽  
The Common ◽  
Quantitative Changes ◽  
Beta Galactosidase

Milk samples (186) were obtained at various stages of lactation from 27 common brushtail possums (Trichosurus vulpecula). Qualitative and quantitative changes in the milk carbohydrates during early and mid-lactation were similar to those previously seen in other marsupials; the principal carbohydrate was lactose early in lactation and higher oligosaccharides in mid-lactation, and the hexose concentration reached a peak during mid-lactation. However, the late-lactation milk was unusual in that the carbohydrate was mainly lactose and its concentration remained relatively high (3.5 to 5.5%). In contrast to earlier findings on the milk of the tammar wallaby (Macropus eugenii), little or no nucleotide pyrophosphatase, beta-galactosidase and alkaline phosphatase activities were detected late in lactation.

scholarly journals Changes in Milk Carbohydrates and Electrolytes during Early Lactation in the Tammar Wallaby, Macropus eugenii

1984 ◽  
Vol 37 (2) ◽  
pp. 1 ◽  
Author(s):  
M Messer ◽  
M Griffiths ◽  
B Green
Keyword(s):  
Post Partum ◽  
Tammar Wallaby ◽  
Early Lactation ◽  
Macropus Eugenii ◽  
Milk Samples

Milk samples were collected from 13 tammar wallabies immediately post partum and from a further 10 animals at various times up to 3 weeks after birth.

Studies on the Nutrition of Macropodine Marsupials. 5.microbial Fermentation in the Forestomach of Thylogale Thetis and Macropus Eugenii.

1983 ◽  
Vol 31 (4) ◽  
pp. 433 ◽  
Author(s):  
DW Dellow ◽  
JV Nolan ◽  
ID Hume
Keyword(s):  
Tammar Wallaby ◽  
Microbial Fermentation ◽  
Ammonia Production ◽  
Macropus Eugenii ◽  
Microbial Nitrogen ◽  
Nitrogen Intake ◽  
Digestible Organic Matter ◽  
Production Of Ammonia

Rates of volatile fatty acid (VFA) and ammonia production at different sites along the forestomach of Thylogale thetis, the red-necked pademelon, and Macropus eugenii, the tammar wallaby, were estimated in vitro and in vivo. Estimates of the flow of microbial nitrogen from the stomach were also obtained in vivo. In both species VFA production was faster in vitro and in vivo in the sacciform forestomach than in the tubiform forestomach. The ratio of total VFA production to digestible organic matter (OM) intake was similar in the 2 species, and similar to published estimates for ruminants. Net production of ammonia in vivo was faster in the sacciform forestomach than in the tubiform forestomach of T. thetis but not of M. eugenii. The ratio of total net ammonia production to nitrogen intake was similar in the 2 species, and net synthesis of microbial protein per kilogram OM apparently fermented in the stomach of T. thetis and M. eugenii was similar to that in ruminants. The decrease in fermentation rate along the forestomach of both species was consistent with the previously reported pattern of apparent digestion of OM in the macropodine stomach. Although this pattern of microbial activity differs from that in ruminants, the overall fermentation is extensive. Thus the lower fibre digestibility often found in macropodines compared with sheep may be related to a faster rate of passage of particulate digesta through the macropodine forestomach, but it is not due to a less efficient microbial fermentation.

Studies on the mechanism of acute inhibition of thyroglobulin hydrolysis by iodine

1985 ◽  
Vol 108 (4) ◽  
pp. 511-517 ◽  
Author(s):  
Nandalal Bagchi ◽  
Birdie Shivers ◽  
Thomas R. Brown
Keyword(s):  
Time Course ◽  
Period 2 ◽  
Iodotyrosine Deiodinase ◽  
Rate Of Hydrolysis ◽  
Underlying Mechanisms ◽  
Excess Iodide ◽  
Sites Of Action ◽  
Hydrolysis Of

Abstract. Iodine in excess is known to acutely inhibit thyroidal secretion. In the present study we have characterized the time course of the iodine effect in vitro and investigated the underlying mechanisms. Labelled thyroid glands were cultured in vitro in medium containing mononitrotyrosine, an inhibitor of iodotyrosine deiodinase. The rate of hydrolysis of labelled thyroglobulin was measured as the proportion of labelled iodotyrosines and iodothyronines recovered at the end of culture and was used as an index of thyroidal secretion. Thyrotrophin (TSH) administered in vivo acutely stimulated the rate of thyroglobulin hydrolysis. Addition of Nal to the culture medium acutely inhibited both basal and TSH-stimulated thyroglobulin hydrolysis. The effect of iodide was demonstrable after 2 h, maximal after 6 h and was not reversible upon removal of iodide. Iodide abolished the dibutyryl cAMP induced stimulation of thyroglobulin hydrolysis. Iodide required organic binding of iodine for its effect but new protein or RNA synthesis was not necessary. The inhibitory effects of iodide and lysosomotrophic agents such as NH4C1 and chloroquin on thyroglobulin hydrolysis were additive suggesting different sites of action. Iodide added in vitro altered the distribution of label in prelabelled thyroglobulin in a way that suggested increased coupling in the thyroglobulin molecule. These data indicate that 1) the iodide effect occurs progressively over a 6 h period, 2) continued presence of iodide is not necessary once the inhibition is established, 3) iodide exerts its action primarily at a post cAMP, prelysosomal site and 4) the effect requires organic binding of iodine, but not new RNA or protein synthesis. Our data are consistent with the hypothesis that excess iodide acutely inhibits thyroglobulin hydrolysis by increasing the resistance of thyroglobulin to proteolytic degradation through increased iodination and coupling.

scholarly journals Catalytic activity and stereoselectivity of engineered phosphotriesterases towards structurally different nerve agents in vitro

2021 ◽  
Author(s):  
Anja Köhler ◽  
Benjamin Escher ◽  
Laura Job ◽  
Marianne Koller ◽  
Horst Thiermann ◽  
...  
Keyword(s):  
Plasma Clearance ◽  
Nerve Agents ◽  
Inhibition Assay ◽  
Ache Inhibition ◽  
Catalytic Activities ◽  
Chiral Lc ◽  
Hydrolysis Of ◽  
Medical Countermeasures

AbstractHighly toxic organophosphorus nerve agents, especially the extremely stable and persistent V-type agents such as VX, still pose a threat to the human population and require effective medical countermeasures. Engineered mutants of the Brevundimonas diminuta phosphotriesterase (BdPTE) exhibit enhanced catalytic activities and have demonstrated detoxification in animal models, however, substrate specificity and fast plasma clearance limit their medical applicability. To allow better assessment of their substrate profiles, we have thoroughly investigated the catalytic efficacies of five BdPTE mutants with 17 different nerve agents using an AChE inhibition assay. In addition, we studied one BdPTE version that was fused with structurally disordered PAS polypeptides to enable delayed plasma clearance and one bispecific BdPTE with broadened substrate spectrum composed of two functionally distinct subunits connected by a PAS linker. Measured kcat/KM values were as high as 6.5 and 1.5 × 108 M−1 min−1 with G- and V-agents, respectively. Furthermore, the stereoselective degradation of VX enantiomers by the PASylated BdPTE-4 and the bispecific BdPTE-7 were investigated by chiral LC–MS/MS, resulting in a several fold faster hydrolysis of the more toxic P(−) VX stereoisomer compared to P(+) VX. In conclusion, the newly developed enzymes BdPTE-4 and BdPTE-7 have shown high catalytic efficacy towards structurally different nerve agents and stereoselectivity towards the toxic P(−) VX enantiomer in vitro and offer promise for use as bioscavengers in vivo.

scholarly journals Stimulation of Interleukin-10 Production by Acidic β-Lactoglobulin-Derived Peptides Hydrolyzed with Lactobacillus paracasei NCC2461 Peptidases

2004 ◽  
Vol 11 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Guénolée Prioult ◽  
Sophie Pecquet ◽  
Ismail Fliss
Keyword(s):  
Oral Tolerance ◽  
Immunosuppressive Agents ◽  
Interleukin 10 ◽  
Lactobacillus Paracasei ◽  
In Vitro Hydrolysis ◽  
Ifn Γ ◽  
Immunomodulatory Peptides ◽  
Β Lactoglobulin

ABSTRACT We have previously demonstrated that Lactobacillus paracasei NCC2461 may help to prevent cow's milk allergy in mice by inducing oral tolerance to β-lactoglobulin (BLG). To investigate the mechanisms involved in this beneficial effect, we examined the possibility that L. paracasei induces tolerance by hydrolyzing BLG-derived peptides and liberating peptides that stimulate interleukin-10 (IL-10) production. L. paracasei peptidases have been shown to hydrolyze tryptic-chymotryptic peptides from BLG, releasing numerous small peptides with immunomodulating properties. We have now shown that acidic tryptic-chymotryptic peptides stimulate splenocyte proliferation and gamma interferon (IFN-γ) production in vitro. Hydrolysis of these peptides with L. paracasei peptidases repressed the lymphocyte stimulation, up-regulated IL-10 production, and down-regulated IFN-γ and IL-4 secretion. L. paracasei NCC2461 may therefore induce oral tolerance to BLG in vivo by degrading acidic peptides and releasing immunomodulatory peptides stimulating regulatory T cells, which function as major immunosuppressive agents by secreting IL-10.

Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2257-2266 ◽  
Author(s):  
Helmuth Adelsberger ◽  
Christian Hertel ◽  
Erich Glawischnig ◽  
Vladimir V. Zverlov ◽  
Wolfgang H. Schwarz
Keyword(s):  
Extracellular Enzymes ◽  
Enzyme System ◽  
Thermophilic Bacterium ◽  
Recombinant Enzymes ◽  
Type Mode ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of

Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), β-xyloside (bxlA, bxlB, bglZ) and α-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.

Acid and neutral sphingomyelinases: roles and mechanisms of regulation

2004 ◽  
Vol 82 (1) ◽  
pp. 27-44 ◽  
Author(s):  
Norma Marchesini ◽  
Yusuf A Hannun
Keyword(s):  
Nitric Oxide ◽  
Molecular Mechanisms ◽  
Caveolin 1 ◽  
Niemann Pick Disease ◽  
Extracellular Stimuli ◽  
Niemann Pick ◽  
Hydrolysis Of ◽  
Pick Disease

Ceramide, an emerging bioactive lipid and second messenger, is mainly generated by hydrolysis of sphingomyelin through the action of sphingomyelinases. At least two sphingomyelinases, neutral and acid sphingo myelinases, are activated in response to many extracellular stimuli. Despite extensive studies, the precise cellular function of each of these sphingomyelinases in sphingomyelin turnover and in the regulation of ceramide-mediated responses is not well understood. Therefore, it is essential to elucidate the factors and mechanisms that control the activation of acid and neutral sphingomyelinases to understand their the roles in cell regulation. This review will focus on the molecular mechanisms that regulate these enzymes in vivo and in vitro, especially the roles of oxidants (glu ta thi one, peroxide, nitric oxide), proteins (saposin, caveolin 1, caspases), and lipids (diacylglycerol, arachidonic acid, and ceramide).Key words: sphingomyelinase, ceramide, apoptosis, Niemann-Pick disease, FAN (factor associated with N-SMase activation).

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