Feline cytotoxic immune mechanisms against virus-associated leukemia and fibrosarcoma

Humoral and cellular cytotoxic immune mechanisms of cats were compared against feline leukemia virus (FeLV)- and feline sarcoma virus (FeSV)-transformed cells. The groups of animals studied were nonexposed control cats; FeLV-infected immune or viremic tumor-bearing cats; FeSV-inoculated tumor progressor or regressor cats, and cats immunized with FeSV-transformed autochthonous fibroblasts (ATF). Sera containing complement-dependent antibodies (CDA), which lysed FeLV-producer lymphoma lines, had no cytotoxic effects when tested against FeLV-producer FeSV-transformed fibroblasts. Sera with lytic CDA activity were also tested for antibody-dependent cellular cytotoxic (ADCC) effects with peripheral blood lymphocytes (PBL) from nonimmune cats. No ADCC activity was detected against either lymphoid or fibroblast target lines. To demonstrate that cat PBL contained ADCC effector cells, antibody-coated murine target cells were employed and positive results obtained. Natural killer (NK) assays were performed using PBL from normal and tumor-bearing cats. Cytotoxic effects were only detectable to FeLV-producer lymphomas, and comparable levels of NK activity were found in normal and lymphoid tumor-bearing animals. In cats immunized with ATF, a population of effector cells was found in peripheral blood which had functional characteristics of cytotoxic T lymphocytes (CTL). The killing of ATF by CTL-like cells was not inhibited by FeLV/FeSV immune sera or by sera from autochthonous immune cats. The comparative importance of humoral and cellular cytotoxic mechanisms against FeLV- and FeSV-induced tumors is discussed.     

The synthesis and biological activity of Ala3,14-somatostatin

The tetradecapeptide H-Ala-Gly-Ala-Lys-Asn-Phe-Phe-Trp-Lys-Thr-Phe-Thr-Ser-Ala-OH (Ala³, 14-somatostatin) an analog of the somatotropin release inhibiting factor (somatostatin SRIF) was synthesized by solid phase peptide methods. It shows somatotropin release inhibiting activity $\text{in vitro}$ at 5 μg/ml concentration.     

A Comparison of the Iron Bonding in Anhydrohemoglobin and Anhydromyoglobin

Mössbauer effect measurements show that the ferrous ions in dehydrated deoxymyoglobin are in the high spin state while those in dehydrated deoxyhemoglobin (AHb) are equally distributed between high and low spin states. It is concluded that the two spin states present in AHb are associated with the iron site difference of the α- and β-chains.     

Determination of each constituent in mixtures of catechol and protocatechuic acid,quinol and gentisic acid,phenol and p-hydroxybenzoic acid,and pyrogallol and gallic acid

Simple, rapid spectrophotofluorometric methods were developed for determining each constitutent in the mixtures of catechol and protocatechuic acid and in mixtures of quinol and gentisic acid. A colorimetric method involving the use of 4-aminoantipyrine and extraction with chloroform was proposed for determining each constituent in mixtures of phenol and p-hydroxybenzoic acid. Two simple and rapid colorimetric methods were used in conjunction to determine each constituent in mixtures of pyrogallol and gallic acid. The accuracy of all methods was within ±5%.     

Exopolysaccharide Colanic Acid and Its Occurrence in the Enterobacteriaceae

A study of strains from the genera Salmonella, Escherichia, and Aerobacter has shown that under appropriate conditions many strains produce an exopolysaccharide slime of identical composition, which has been identified as colanic acid on the basis of its chemical composition and its sensitivity to certain bacteriophage-induced depolymerase enzymes. Chemical analysis shows that the polysaccharide contains O-acetyl groups in addition to the sugars glucose, galactose, fucose, and glucuronic acid. Mild acid hydrolysis has led to the isolation of a β-glucosylfucose in addition to glucuronic acid containing oligosaccharides. Many strains were found to synthesize colanic acid under normal conditions of growth or under conditions favoring polysaccharide synthesis, whereas others only synthesized colanic acid when the control mechanism was derepressed by p-fluorophenylalanine.     

Synthesis of Bacterial Flagella: Chromosomal Synchrony and Flagella Synthesis

Synchronous cultures of Bacillus subtilis 168 M were obtained from light-density spores germinated at 46 C and grown at 37 C. This procedure synchronizes both cell division and chromosome replication. The chromosome synchrony was demonstrated by using transformation to measure changes in marker frequency during the cell cycle. The synthesis of two enzymes and of bacterial flagellar protein was also followed. All of the proteins were found to be synthesized continuously with an abrupt doubling in the rate of synthesis at a specific time in the cell cycle. The time at which the doubling occurred for each enzyme corresponded to the time at which the structural gene for the enzyme was replicated. The doubling of the rate of flagella synthesis corresponded to the time of replication of the hisA1 gene. We conclude that the genetic locus for the factors involved in the rate-limiting steps in flagella synthesis are located on the genetic map near the hisA1 locus.     

Morphogenetic studies of a genetically controlled tumor-like condition in Lycopersicon hybrids

Summary A dominant tumor-like condition recently isolated in a tomato hybrid is described from the viewpoint of morphogenesis. Tumors, consisting of masses of enlarged parenchymatous cells, generally appear on the ventral surface of the third leaf and the subsequently formed leaves of the hybrid derivatives. These outgrowths do not differentiate into teratomas. Abortive floral buds develop under greenhouse conditions and the tumorous plants are much dwarfed compared to the normal segregants of the same population. the same tumor genotype behaves differently under the field conditions: it grows and blossoms like the normal plants, setting fruits with viable seeds, and tumors fail to develop. Thus, tumor expression and general morphology of the tumor plants are greatly modified by environmental conditions.Tissue culture studies employing a variety of media have shown that tissues excised from tumor-producing plants are not autonomous with respect to growth hormones, nor are tissues from the non-tumorous segregants. Nevertheless, tissues from tumor and non-tumor genotypes show different growth requirements. Tumor and non-tumor tomatoes can thus be distinguished on the basis of in vitro growth responses, a result consistent with their different genetic constitution. Differentiation of buds or roots was not observed in either type of tissue.Abbreviations used GA gibberellic acid - IAA 3-indoleacetic acid - 2.4-D 2.4-dichlorophenoxyacetic acid Work Supported by National Science Foundation Grant GB-3198 and funds from The Cairncrest Foundation.