Short communication: Relationship of activity and rumination to abundance of pest flies among organically certified cows fed 3 levels of concentrate.

The objectives of this study were to evaluate activity, rumination time, and their association with 3 kinds of pasture flies for organic dairy cows (n=57) fed 3 grain supplementation strategies during the grazing season from May to September 2013. Cows were assigned to 1 of 3 replicate supplementation groups: (1) no corn-grain supplementation (100% pasture, PAS, n=19); (2) low corn-grain (2.72kg/cow per day, LG, n=19); and (3) high corn-grain (5.44kg/cow per day, HG, n=19). Cows calved during 2 seasons (fall and spring) at the University of Minnesota West Central Research and Outreach Center, Morris, from October to December 2012 and March to May 2013. Supplement (corn-grain and minerals) was fed in a total mixed ration of corn silage and alfalfa silage, and at least 30% of diet dry matter intake for LG and HG cows consisted of pasture. Activity and rumination time (daily and 2-h blocks of time) were monitored electronically using HR-LD tags (SCR Engineers Ltd., Netanya, Israel) for 125d. Activity (cow body movement and head movement) was reported in activity units from SCR DataFlow II software, and rumination times were reported in minutes per day. PROC HPMIXED in SAS (SAS Institute Inc., Cary, NC) was used for statistical analysis, and independent variables were season of calving (fall or spring), month of grazing (June to September), supplementation group, and interactions of month of grazing and supplementation group. Replicate was a random effect with repeated measures. Daily activity was higher for PAS cows (1,138 activity units) than for HG cows (1,001 activity units), and LG cows (1,019 activity units). Daily activity was highest in July (1,258 activity units) and lowest in September (819 activity units). Rumination was not different for PAS (397min/d), LG (384min/d), or HG (370min/d) cows. Daily rumination was greater in September (402min/d) than in July (361min/d). Daily activity increased rapidly between 0600-0800h and 1600-1800h. From 1800 to 2000h, cows had a rapid decline in activity until 0600h the next day. All supplementation groups had the greatest rumination activity from 0200 to 0400h and the least between 1000 and 1200h. Greater activity of cows on a herd basis was moderately correlated with increased fly populations. Monthly activity patterns of grazing cows were associated with fly populations on cows.

Purification of a sialyltransferase from bovine colostrum by affinity chromatography on CDP-agarose.

CDP-hexanolamine agarose was used as an affinity adsorbent to purify a CMP-N-acetylneuraminate: beta-D-galactosyl-glycoprotein N-acetylneuraminyltransferase (EC 2.4.99.1) from bovine colostrum. Upon binding of the enzyme to the adsorbent, elution is achieved either nonspecifically, with 0.5 to 1.0 M sodium chloride, or specifically, with CDP. A highly purified sialyltransferase is obtained with a specific activity 440,000 times that of whole colostrum. Fractionation of the purified enzyme by gel filtration gives two species with different molecular weights but equal specific activities toward asialo-alpha1-acid glycoprotein (26.0 to 28.0 micronmol/min/mg of enzyme). The molecular weights of these two forms are about 56,000 and 43,000 as judged by sodium doedcyl sulfate-gel electrophoresis, sedimentation equilibrium, and gel filtration. The catalytic properties of both forms have been examined (Paulson, J. C., Rearick, J. I., and Hill, R. L. (1977) J. Biol. Chem. 252, 2363-2371). It is concluded that the lower molecular weight form may be a partially degraded species of the enzyme of higher molecular weight.

Enzymatic properties of beta-D-galactoside alpha2 leads to 6 sialytransferase from bovine colostrum.

The substrate specificity and kinetic properties of a pure sialyltransferase from bovine colostrum have been examined. The transferase appears to incorporate sialic acid into the sequence, NeuAcalpha2 leads to 6Galbeta1 leads to 4GlcNAc, which is commonly found in glycoproteins. It has a strict substrate specificity for CMP-NeuAc and forms only the alpha2 leads to 6 sialyl linkage with beta-D-galactosides. N-Acetyllactosamine (Galbeta1 leads to 4GlcNAc) and asialo-glycoproteins containing the N-acetyllactosaminyl linkage at the nonreducing ends of the oligosaccharides prosthetic groups are the best acceptor substrates. Isomers of N-acetyllactosamine with beta1 leads to 3 or beta1 leads to 6 glycosidic linkages are less than 1% as effective as acceptor substates as the beta1 leads to 4-linked isomer. Lactose (Galbeta1 leads to 4Glc) is also a poor acceptor, indicating the importance of the 2-acetamido group in the N-acetylglucosaminyl residues. The unnatural substrate beta-methyl-L-arabinopyrano-side, a five-carbon analog of beta-methyl-D-galactoside which contains no 6-hydroxyl, also acts as a poor acceptor of the transferase and the sialylated product has been partially characterized. Kinetic properties of the enzyme in the presence and absence of inhibitors suggest that the transferase has an equilibrium random order mechanism.

Microtubules and axoplasmic transport. Inhibition of transport by podophyllotoxin: an interaction with microtubule protein.

Pharmacological evidence is presented for the involvement of microtubules in the process of fast axoplasmic transport. A quantitative measure of the inhibition of axoplasmic transport in an in vitro preparation of rat sciatic nerve is described. The alkaloids colchicine, podophyllotoxin, and vinblastine, which are known both to disrupt microtubules and to bind to the protein subunit of microtubules, are inhibitors of axoplasmic transport. Lumicolchine and picropodophyllin, unlike their respective isomers colchicine and podophyllotoxin, are poor inhibitors of axoplasmic transport. The dissociation constants for the binding of colchicine, lumicolchicine, podophyllotoxin, and picropodophyllin to purified microtubule protein from rat brain have been measured. Inhibition of axoplasmic transport by these drugs correlates favorably with their affinities of microtubule protein.