Influence of Ileo-Caecal Cannulation and Oxytetracycline on Ileo-Caecal and Rectal Coliform Populations in Pigs

The effect of surgery (insertion of an ileo-caecal cannula) and a subsequent parenteral treatment with oxytetracycline on the ileo-caecal and rectal coliform populations in 7 Swedish Yorkshire castrates were studied. Samples were collected during surgery as well as 3, 7, 14 and 20 days post surgery. The diversity of the enteric coliform flora was initially high both in the ileo-caecal ostium and in rectum. No alteration in the diversity of the enteric coliform flora was observed following surgery and treatment with oxytetracycline. As the insertion of ileo-caecal cannulas did not affect the intestinal coliform flora this study gives support to the use of this technique to mirror processes in the small intestine of pigs. Further, the diversity of the enteric coliform flora was unaffected by the parenteral treatment with oxytetracycline.     

Structural maintenance of chromosomes (SMC) proteins, a family of conserved ATPases

The structural maintenance of chromosomes (SMC) proteins are essential for successful chromosome transmission during replication and segregation of the genome in all organisms. SMCs are generally present as single proteins in bacteria, and as at least six distinct proteins in eukaryotes. The proteins range in size from approximately 110 to 170 kDa, and each has five distinct domains: amino- and carboxy-terminal globular domains, which contain sequences characteristic of ATPases, two coiled-coil regions separating the terminal domains and a central flexible hinge. SMC proteins function together with other proteins in a range of chromosomal transactions, including chromosome condensation, sister-chromatid cohesion, recombination, DNA repair and epigenetic silencing of gene expression. Recent studies are beginning to decipher molecular details of how these processes are carried out.     

Hormonally regulated programmed cell death in barley aleurone cells

Cell death was studied in barley (cv Himalaya) aleurone cells treated with abscisic acid and gibberellin. Aleurone protoplasts incubated in abscisic acid remained viable in culture for at least 3 weeks, but exposure to gibberellin initiated a series of events that resulted in death. Between 4 and 8 days after incubation in gibberellin, >70% of all protoplasts died. Death, which occurred after cells became highly vacuolated, was manifest by an abrupt loss of plasma membrane integrity followed by rapid shrinkage of the cell corpse. Hydrolysis of DNA began before death and occurred as protoplasts ceased production of alpha-amylase. DNA degradation did not result in the accumulation of discrete low molecular weight fragments. DNA degradation and cell death were prevented by LY83583, an inhibitor of gibberellin signaling in barley aleurone. We conclude that cell death in aleurone cells is hormonally regulated and is the final step of a developmental program that promotes successful seedling establishment.     

The former southern distribution of New World manatees (Trichechus spp.)

Records of New World manatees in 16th and 17th century literature extend the former distribution of Trichechus manatus to about 20° S. Early 19th century records confirm this range, but the species has since been exterminated from these southerly localities and is now rarely found to the south of Cayenne (French Guiana). Manatees probably did not occur at Rio de Janeiro or Santos, the Sao Vicente "monster" most likely being a pinnepede. The former distribution of T. manatus seems to have been bounded by the 24^° C mean annual isotherm.