The transfer of serum IgG1 antibody into the gastrointestinal tract in newborn calves

Transfer of functional blood IgG1 to the gastrointestinal tract was measured in neonatal calves. Radiolabelled immunoglobulin G1 (IgG1) anti-DNP antibody was administered to 2 day old calves by intravenous injection. The serum clearance rate was measured and was compared to the rate of protein-bound 125I excretion in the feces over a 10 day period to determine the importance of transfer to the gastrointestinal tract as a mechanism of serum IgG1 clearance. The amount of protein-bound and DNP-binding 125I present in the gastrointestinal tract of 10 day old calves at necropsy was also measured. Fecal excretion of protein-bound 125I accounted for 32% of the serum 125I-IgG1 clearance. Protein-bound 125I was present in the gastrointestinal tract at necropsy in amounts estimated to account for 68% of the total 125I-IgG1 clearance, and retained 65% of the DNP-binding ability of the original antibody. The discrepancy between the fecal excretion (32% of total IgG1 clearance) and the GI clearance estimated from protein-bound 125I in the gut (68% of total IgG1 clearance) is explained in part by IgG1 proteolysis occurring after transfer to the gastrointestinal tract but before fecal excretion. These results indicate that transfer to the calf gastrointestinal tract accounts for most IgG1 clearance in young calves, and that the intestinal antibody retains antigen binding function and may contribute to intestinal immunity.     

Polymers with Very Low Polydispersities from Atom Transfer Radical Polymerization

A radical polymerization process that yields well-defined polymers normally obtained only through anionic polymerizations is reported. Atom transfer radical polymerizations of styrene were conducted with several solubilizing ligands for the copper(I) halides: 4,4'-di-tert-butyl, 4,4'-di-n-heptyl, and 4,4'-di-(5-nonyl)-2,2'-dipyridyl. The resulting polymerizations have all of the characteristics of a living polymerization and displayed linear semilogarithmic kinetic plots, a linear correlation between the number-average molecular weight and the monomer conversion, and low polydispersities (ratio of the weight-average to number-average molecular weights of 1.04 to 1.05). Similar results were obtained for the polymerization of acrylates.     

Nearly singular magnetic fluctuations in the normal state of a high-Tc cuprate superconductor

Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, Tc = 35 kelvin, up to 350 kelvin) of single crystals of La1.86Sr0.14CuO4. The peaks that dominate the fluctuations have amplitudes that decrease as T-2 and widths that increase in proportion to the thermal energy, kBT (where kB is Boltzmann's constant), and energy transfer added in quadrature. The nearly singular fluctuations are consistent with a nearby quantum critical point.     

Phosphorus supplements and fluorosis in cattle—a northern Australian experience

SUMMARY Chronic fluoride toxicosis caused lameness, dental lesions and illthrift in an extensive beef cattle herd in northern Australia. Up to 15% of the herd was lame and the disease forced the culling of large numbers of cows. The source of fluoride was fertiliser-grade monoammonium and diammonlum phosphate fed as part of a mineral supplement. Large quantities of mineral supplement were provided to the cattle because lameness was attributed to phosphorus deficiency, which is endemic in the area. Most lameness developed in the late dry season in the post-lactation phase. Severe lameness was caused by fractured pedal bones.     

KINETICS OF DICHLOBENIL DEGRADATION IN SOIL

Summary. The rates of degradation of dichlobenil (2,6-dichlorobenzonitrile) in soil were determined at 67 and 267°C. The degradation followed first-order kinetics but at 67°C this occurred after an initial lag period of 10 weeks. The half-lives were 28 weeks (+ 10 weeks lag) at 6.7°C and 19 weeks at 26.7°C. The activation energy for the decomposition was the relatively low value of 3.57 kcal/mole, indicating that the degradation of dichlobenil is not as markedly affected by temperature as that of many other herbicides. The only detectable metabolite was 2,6-dichlorobenzamide, a compound that should have a substantially lower vapour pressure and a higher affinity for surfaces than the parent compound. Cinétique de la dégradation du dichlobénil dans le sol Résumé. Les taux de dégradation du dichlobénil (2,6-dichlorobenzonitrile) dans le sol ont été détermines à 6,7 et 26,7°C. La déSgradation suivit une loi cinétique du premier ordre, mais à 6,7°C ceci se produisit aprés une période initiate de latence de 10 semaines. Les demi-vies furent de 28 semaines (plus 10 semaines de latence) a 6,7°C et 19 semaines à. 26,7°C. L'énergie d'activation pour la décomposition s'établit à la valeur relativement faible de 3,57 kcal/mole; ceci indique que la dégradation du dichlobénil n'est pas aussi profondément affcctée par la température quc celle de beaucoup d'autres herbicides. Le seul métabolite detectable fut le 2,6-dichlorobenzamide, composé qui devrait avoir une pression de vapeur notablement plus faible et une affinité plus grande pour les surfaces que le composé apparenté. Kinetik des Dichlohenil-Abbaus im Boden Zusammenfassung. Es wurde die Abbaugeschwindigkeit von Dichlobenil (2,6-Dichlorbenzonitril) im Boden bei 6,7°C und 26,7°C bestinimt. Der Abbau entsprach einer Reaktion erster Ordnung. Bei 6,7°G setzte der Abbau nach einer lag-Phase von 10 Wochen ein. Die Halbwertzeiten betrugen 28 Wochen (+10 Wochen lag-Phase) bei 6,7°C und 19 Wochen bei 26,7°C. Die Aktivierungsenergie war verhältnisniässig niedrig und betrug 3,57 Kcal/Mol und zeigt, dass der Abbau von Dichlobenil durch Temperatur nicht so stark beeinflusst wird wie bei vielen anderen Herbiziden. Der einzige nachweisbare Metabolit war 2,6-Dichlorbenzamid, der einen wcsentlich nieddgeren Dampfdruck und eine grössere Affinität gegenüber Oberfiächen haben dürfte als die ursprüngliche Verbindung.     

Feedstuffs as a vehicle of cattle exposure to Escherichia coli O157:H7 and Salmonella enterica

Feed has been reported as a vehicle for transmission of Salmonella enterica in cattle and several lines of evidence suggest that feed can be a vehicle for transmitting Escherichia coli O157:H7 as well. To show whether microbial contamination of feeds could contribute to the populations of S. enterica and E. coli O157:H7 on a farm, we compared isolates from feed samples to bovine fecal isolates from the same farm using pulsed-field gel electrophoresis (PFGE). Four of 2365 component feed samples (0.2%) and 1 of 226 feed mill samples (0.4%) were positive for E. coli O157:H7. Twenty of 2405 (0.8%) component feed samples and none of 226 feed mill samples were positive for Salmonella. PFGE profiles from E. coli O157:H7 isolated from a component feed sample closely resembled that from a fecal isolate collected later from the same farm, and a similar observation was made of a Salmonella Tyhpimurium isolate from component feed on another farm. There were indistinguishable PFGE profiles from component feed Salmonella Tyhpimurium DT104 isolates and fecal isolates from the same farm. These results provide evidence for a role of cattle feed in transmission of E. coli O157:H7; S. enterica; cattle-bacteria.     

Isolation,Culture and Identification of Testis Sertoli Cells in Mongolian Horses in vitro

To study a simple and rapid separation of testis Sertoli cells in Mongolian horses and ensure their activity,the testis tissue of two-year-old Mongolian horses was mechanically isolated under a low temperature environment in this experiment,and 1-3 g of testis tissue was chopped,the free red blood cells and interstitial cells were removed by gravity precipitation method.0.1% collagenase Ⅳ and 0.25% trypsin-EDTA were used for tissue digestion, and cells were cultured in medium containing 10% fetal bovine serum.After inoculation,the purified Sertoli cells were isolated and purified by differential sticking method,and the impurity cells were removed by Tris-HCl infiltration method,and were identified by alkaline phosphatase (AKP) staining,HE staining and Real-time quantitative PCR.The results showed that most of the cells began to adhere to the wall after culture 24 h,and the shape of the cells was oval.After culture 48 h,the cytoplasm increased and the refraction became stronger.After culture 3-4 d,the cytoplasm of the cells expanded into tight junction.At this time,the cells were triangular with obvious nucleoli.After culture 6-7 d,the cells entered the stable phase.Real-time quantitative PCR results showed that the expression of GATA4 and GDNF genes were extremely significantly expressed in cultured cells (P<0.01).AKP staining supported the negative expression in Sertoli cells,indicating that the isolated cultured cells were indeed Sertoli cells.In this experiment,tissue was treated by mechanical separation and two-step enzyme digestion,and testicular support cells were obtained quickly and efficiently,the method of culturing Sertoli cells in Mongolian horses testis in vitro was successfully constructed.     

Escherichia coli O157:H7 – Discerning Facts from Fiction: An Integrated Research and Extension Project for Multiple Audiences

The O157:H7 (EcO157) epidemiology of Shiga‐toxin‐producing Escherichia coli (STEC) in cattle is complex, and myths about pre‐harvest control are perpetuated. The objectives of this project were to identify perpetuated misinformation and inform four audiences about evidence‐based risks and pre‐harvest control of EcO157 by addressing: (i) EcO157 epidemiology and pre‐harvest control; (ii) how food safety policy is created; and (iii) how to present accurate information about EcO157. An environmental scan using a daily Internet search helped identify themes for education. A literature review of pre‐harvest control measures contributed to the development of educational materials (fact sheets, website, web presentations and conferences). Conference 1 was a webinar with 315 registrants, 10 countries including 41 US states and four Canadian provinces. Most participants felt confident in using their new knowledge, more than half felt confident enough to answer EcO157 questions from the public and many would recommend the recorded version of the webinar to colleagues. Conference 2 was live in the Washington, DC, area with most participants employed by the US government. All agreed that they better understood pre‐harvest control, how food safety policy was made, and were confident they could create an effective message about STEC pre‐harvest control. Videos were posted and received 348 Internet visitors within 2 months. Conference 3 was a webinar with a live audience and Twitter feeds, targeting people who give nutrition advice. Almost all ranked the programme good to excellent and relevant to their work. About 25% indicated that they would share: ‘grass‐fed beef is not safer than grain‐fed’, 25% would share information on effectiveness of cattle vaccines, and 14% would share information on message mapping. Across all conferences, major changes in knowledge included the following: there is no additional risk of EcO157 shedding from grain‐fed versus grass‐fed cattle, pre‐harvest vaccination is efficacious, and production systems (pasture versus confinement) do not affect EcO157 shedding rates.