Transformation studies on human fibroblasts from familial polyposis coli patients and normal donors

Transformation experiments have been carried out on human diploid fibroblasts derived from normal individuals and those from 2 groups with dominantly inherited cancer predisposition, familial polyposis coli (FPC), and multiple endocrine neoplasia, type 2 (MEN-2). Treatment with a single or multiple doses of the carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), resulted in limited anchorage-independent (AI) growth in both normal and FPC cultures; no permanent cell lines were produced but FPC cells showed increased proliferation with low doses of the carcinogen. Carcinogen treatment followed by application of the tumour promoter, 12-O-tetradecanoyl phorbol-13-acetate (TPA), for 38 weeks was insufficient to cause full transformation in cultures derived from normal people or MEN-2 patients although AI growth was induced in all 3 cell types. Three FPC cultures exhibited an extended life span over the solvent controls. Two of these are still actively dividing and have a clonal pseudodiploid karyotype.     

Comparison of purified bovine heart and rat liver 6-phosphofructo-2-kinase. Evidence for distinct isoenzymes.

Rat liver and bovine heart 6-phosphofructo-2-kinase were purified by the same procedure. Compared with the liver enzyme, the heart enzyme had a smaller apparent Mr, different kinetic properties, was not inactivated by cyclic AMP-dependent protein kinase, and contained less fructose-2,6-bisphosphatase activity. These differences suggest that heart and liver 6-phosphofructo-2-kinase are distinct isoenzymes. Likewise, 6-phosphofructo-2-kinase from rat heart and skeletal muscle was not inactivated on treatment with cyclic AMP-dependent protein kinase.     

Synthesis and characterization of the oxygen and desthio analogues of glutathione as dead-end inhibitors of glutathione S-transferase

The oxygen analogue, gamma-L-Glu-L-SerGly (GOH) and desthio analogue, gamma-L-Glu-L-AlaGly (GH) have been synthesized by a simple three step procedure involving active ester coupling of N-t-BOC-alpha-(4-nitrophenyl)-L-glutamate to L-SerGly and L-AlaGly, respectively. The two peptides are excellent dead-end inhibitors of isozymes 3-3 and 4-4 of rat liver glutathione S-transferase. At low fixed concentrations of 1-chloro-2,4-dinitrobenzene (CDNB) GOH and GH are linear competitive inhibitors of isozyme 3-3 vs glutathione with KI values of 13.0 and 116 microM, respectively. Both peptides are non-competitive (mixed-type) inhibitors vs CDNB when glutathione is the fixed substrate. Similar results are obtained with both peptides and isozyme 4-4. The results rule out ordered or ping-pong kinetic mechanisms where the electrophile adds first.     

Effect of music-assisted imagery on neutrophils and lymphocytes

The purpose of this study was to determine the effects of cell-specific mental imagery on neutrophil and lymphocyte cell counts. Subjects (N = 30) were randomly assigned to one of two experimental groups that underwent a 6-week training program focusing on images of morphology, location, and movement of either neutrophils or lymphocytes. Music was used to enhance the imagery of the subjects. Peripheral white blood cell and differential counts were determined before and after the final 20-minute imagery session. Results indicated that neutrophils decreased significantly (p less than .04) in the neutrophil-change group while lymphocytes did not. The reverse occurred in the lymphocyte-change group, with only the lymphocytes decreasing significantly (p less than .03). The authors concluded that under the conditions of the present study, cell-specific imagery was associated with decreases in peripheral blood cell counts of lymphocytes and neutrophils.     

Ultrastructural Studies of Spermiogenesis of Conocephalus saltator (Saussure)

The acrosome of the spermatozoa is the organelle involved in its penetration through the ova membranes during the fertilization process. Several features of this process are considered to be related to the fertilization events e.g. some substance coats outside the membrane. During the maturation process the spermatozoa of Conocephalus saltator develop a coat of tubules and filaments which overly some membrane regions in a specific array. The mature spermatozoa are seen to adhere in these regions and form threads of 20 cells long and five to six wide. It is suggested that the external coat plays a role in this 'sticking' phenomenon.     

Species limits and hybridization zones in Icterus cayanensis–chrysocephalus group (Aves: Icteridae)

One of the best examples of differentiation and hybridization among South American passerine birds is exhibited by Icterus cayanensis (Epaulet Oriole) and Icterus chrysocephalus (Moriche Oriole). Icterus chrysocephalus is a monotypic species restricted to northern South America. Icterus cayanensis is a polytypc species that ranges from Suriname and French Guyana to northern Argentina. Five subspecies are recognized to I. cayanensis. Hybrid zones are known between I. cayanensis and I. chrysocephalus as well as between subspecies of I. cayanenis, even though character variation has never been adequately assessed and mapped. Although molecular data support the hypothesis that I. cayanensis and I. chrysocephalus form a monophyletic group, they do not support the species limits currently recognized within this group. We analysed the geographic variation of plumage characters along the range of this group to map the geographic variation of individual plumage characters and identify the populations that have uniform phenotypic character expression and therefore represent genuine phylogenetic species. We also used molecular data to investigate the phylogenetic relationships among these species. Geographic variation of plumage characters, habitat preferences and molecular data identified four species within I. cayanensis–chrysocephalus clade: an Amazonian species group, formed by I. cayanensis and I. chrysocephalus and a Southern species group composed of I. pyrrhopterus and I. tibialis. The Amazonian species are separated by a relatively narrow hybrid zone along the Amazon valley, whereas the Southern species are separated by a hybrid zone that is larger than the ranges of the two species individually. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 583–597.