Production of Galacto-oligosaccharides by the β-Galactosidase from Kluyveromyces lactis : comparative analysis of permeabilized cells versus soluble enzyme     

Rodriguez-Colinas B  de Abreu MA  Fernandez-Arrojo L  de Beer R  Poveda A  Jimenez-Barbero J  Haltrich D  Ballesteros Olmo AO  Fernandez-Lobato M  Plou FJ 《Journal of agricultural and food chemistry》2011,59(19):10477-10484

The transgalactosylation activity of Kluyveromyces lactis cells was studied in detail. Cells were permeabilized with ethanol and further lyophilized to facilitate the transit of substrates and products. The resulting biocatalyst was assayed for the synthesis of galacto-oligosaccharides (GOS) and compared with two soluble β-galactosidases from K. lactis (Lactozym 3000 L HP G and Maxilact LGX 5000). Using 400 g/L lactose, the maximum GOS yield, measured by HPAEC-PAD analysis, was 177 g/L (44% w/w of total carbohydrates). The major products synthesized were the disaccharides 6-galactobiose [Gal-β(1→6)-Gal] and allolactose [Gal-β(1→6)-Glc], as well as the trisaccharide 6-galactosyl-lactose [Gal-β(1→6)-Gal-β(1→4)-Glc], which was characterized by MS and 2D NMR. Structural characterization of another synthesized disaccharide, Gal-β(1→3)-Glc, was carried out. GOS yield obtained with soluble β-galactosidases was slightly lower (160 g/L for Lactozym 3000 L HP G and 154 g/L for Maxilact LGX 5000); however, the typical profile with a maximum GOS concentration followed by partial hydrolysis of the newly formed oligosaccharides was not observed with the soluble enzymes. Results were correlated with the higher stability of β-galactosidase when permeabilized whole cells were used.  相似文献   

Detection of Usutu virus in a bullfinch (Pyrrhula pyrrhula) and a great spotted woodpecker (Dendrocopos major) in north-west Europe     

Mutien-Marie Garigliany  Didier Marlier  Klara Tenner-Racz  Martin Eiden  Dominique Cassart  Frédéric Gandar  Martin Beer  Jonas Schmidt-Chanasit  Daniel Desmecht 《Veterinary journal (London, England : 1997)》2014,199(1):191-193

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Evaluating the protective efficacy of a trivalent vaccine containing Akabane virus,Aino virus and Chuzan virus against Schmallenberg virus infection     

Silke Hechinger  Kerstin Wernike  Martin Beer 《Veterinary research》2013,44(1):114

Schmallenberg virus (SBV), an arthropod borne pathogen, spread rapidly throughout the majority of Europe since 2011. It can cause a febrile disease, milk drop, diarrhea, and fetal malformation in ruminants. SBV, a member of the Simbu serogroup within the genus Orthobunyavirus, is closely related to Akabane virus (AKAV) and Aino virus (AINOV) among others. In the present study, 4 Holstein-Friesian calves were immunized twice four weeks apart with a multivalent, inactivated vaccine against AKAV and AINOV. Another 4 calves were kept as unvaccinated controls. All animals were clinically, serologically and virologically examined before and after challenge infection with SBV. AKAV- and AINOV-specific neutralizing antibodies were detected one week before challenge infection, while SBV-specific antibodies were detectable only thereafter. SBV genome was detected in all vaccinated animals and 3 out of 4 controls in serum samples taken after challenge infection. In conclusion, the investigated vaccine was not able to prevent an SBV-infection. Thus, vaccines for other related Simbu serogroup viruses can not substitute SBV-specific vaccines as an instrument for disease control.  相似文献   

(Highly pathogenic) avian influenza as a zoonotic agent     

Donata Kalthoff  Anja Globig  Martin Beer 《Veterinary microbiology》2010,140(3-4):237-245

Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential.  相似文献   

Epizootic hemorrhagic disease virus serotype 7 in European cattle and sheep: Diagnostic considerations and effect of previous BTV exposure     

Eschbaumer M  Wernike K  Batten CA  Savini G  Edwards L  Di Gennaro A  Teodori L  Oura CA  Beer M  Hoffmann B 《Veterinary microbiology》2012,159(3-4):298-306

Epizootic hemorrhagic disease virus (EHDV), an arthropod-borne orbivirus (family Reoviridae), is an emerging pathogen of wild and domestic ruminants that is closely related to bluetongue virus (BTV). The present study examines the outcome of an experimental EHDV-7 infection of Holstein cattle and East Frisian sheep. Apart from na?ve animals that had not been exposed to BTV, it included animals that had been experimentally infected with either BTV-6 or BTV-8 two months earlier. In addition, EHDV-infected cattle were subsequently challenged with BTV-8. Samples were tested with commercially available ELISA and real-time RT-PCR kits and a custom NS3-specific real-time RT-PCR assay. Virus isolation was attempted in Vero, C6/36 and KC cells (from Culicoides variipennis), embryonated chicken eggs and type I interferon receptor-deficient IFNAR(-/-) mice. EHDV-7 productively infected Holstein cattle, but caused no clinical signs. The inoculation of East Frisian sheep, on the other hand, apparently did not lead to a productive infection. The commercial diagnostic kits performed adequately. KC cells proved to be the most sensitive means of virus isolation, but viremia was shorter than 2 weeks in most animals. No interference between EHDV and BTV infection was observed; therefore the pre-existing immunity to some BTV serotypes in Europe is not expected to protect against a possible introduction of EHDV, in spite of the close relation between the viruses.  相似文献   

Effects of monensin and essential oils on immunological,haematological and biochemical parameters of cows during the transition period          下载免费PDF全文

C. Drong  U. Meyer  D. von Soosten  J. Frahm  J. Rehage  H. Schirrmeier  M. Beer  S. Dänicke 《Journal of animal physiology and animal nutrition》2017,101(4):791-806

Using a model to generate experimental groups with different manifestations of post‐partum (p.p.) fat mobilization and ketogenesis, the effects of a dietary and a medical intervention on biochemical and haematological parameters, antibody titre, leucocytes subsets and function of transition cows were examined. In total, 60 German Holstein cows were allocated 6 weeks antepartum (a.p.) to 3 high‐body condition score (BCS) groups (BCS 3.95) and 1 low‐BCS group (LC, BCS 2.77). High‐BCS cows received a monensin controlled‐release capsule (HC/MO) or a blend of essential oils (HC/EO) or formed a control group (HC). Parameters were evaluated in 3 periods (day (d) ?42 until calving, 1 until 14 days in milk (DIM), 15 until 56 DIM). Over the course of trial, various parameters were influenced by period with greatest variability next to calving. White blood cell count was higher in the HC (8.42 × 10³/μl) and HC/EO (8.38 × 10³/μl) groups than in the HC/MO group (6.81 × 10³/μl) considering the whole trial. Supplementation of monensin decreased aspartate aminotransferase in comparison with the HC group similar to LC treatment. Bilirubin concentration was nearly doubled in all high‐BCS cows in period 2. In period 3, essential oils increased γ‐glutamyltransferase (80.4 Units/l) in comparison with all other groups and glutamine dehydrogenase (61 Units/l) in comparison with the LC (19 Units/l) and the HC/MO group (18 Units/l). Results suggest that parameters were generally characterized by a high variability around calving. Based on biochemical characteristics, it appeared that the HC cows seemed to have compromised hepatocyte integrity when compared to the LC cows. From the immune parameters investigated, the BVDV antibody response was more pronounced in HC/MO compared to HC/EO.  相似文献   

Optimization of tissue and time for rapid serological and molecular detection of <Emphasis Type="Italic">Apple stem pitting virus</Emphasis> and <Emphasis Type="Italic">Apple stem grooving virus</Emphasis> in apple’     

Sajad Un Nabi  Javid Iqbal Mir  Om Chand Sharma  Desh Beer Singh  Shafia Zaffer  Muneer Ahmad Sheikh  Lubna Masoodi  Kamran Ahmed Khan 《Phytoparasitica》2018,46(5):705-713

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Autocorrelation functions of noisy electron micrographs of stained polynucleotide chains     

A M Fiskin  M Beer 《Science (New York, N.Y.)》1968,159(819):1111-1113

Polyuridylic acid was deposited on carbon films in the presence of the thallous salt of mercury-p-dihydroquinone-O,O-diacetic acid under conditions leading to attachment of one of these molecules to each nucleotide. In electron micrographs of the stained polynucleotide chain, detail was obscured by the noise resulting from the substrate. Optically obtained autocorrelation functions of the distribution of density along the strands revealed peaks suggesting a structural regularity of 8 angstroms; this was interpreted as the internucleotide spacing.  相似文献   

Spirochaetal invasion of the colonic mucosa in a syndrome resembling swine dysentery following experimental Trichuris suis infection in weaned pigs   总被引：2，自引：0，他引：2  

R J Beer  J M Rutter 《Research in veterinary science》1972,13(6):593-595

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Contents of Volume 53     

E. Somarriba  J. Beer  R. G. Muschler 《Agroforestry Systems》2001,53(3):351-353

Volume Contents

Contents of Volume 53  相似文献