Reticuloendotheliosis in a wild turkey (Meleagris gallopavo) from coastal Georgia.

An emaciated wild turkey (Meleagris gallopavo) exhibiting neurologic signs was found on Ossabaw Island, Chatham County, Georgia (USA) on 11 April 1989. The neurologic abnormalities observed included ataxia, drooping wings, head tremors, torticollis, and circling. At necropsy, discrete yellowish-white nodules, varying in size from 2 to 5 mm, were present in the spleen. White nodular lesions approximately 2 mm in diameter were observed beneath the mucosal surface of the distal esophagus. Histopathologic examination of the splenic nodules disclosed large numbers of primitive lymphoreticular cells with leptochromatic nuclei and abundant, slightly basophilic cytoplasms. The mitotic index in these cells was moderate to high. Similar neoplastic cells composed the masses observed in the esophagus. Multifocal, mild perivascular cuffing with mononuclear cells was found in the lumbar spinal cord, brain, and brain stem. Reticuloendotheliosis virus, subtype 3, was isolated from samples of the spleen and liver.     

Hydrolysis of Endogenous Phospholipids by Rat Brain Microsomes

Phosphatidylcholine of rat brain microsomes was labeled in vivo by intracerebral injection of either [3H]oleic acid or [methyl-3H]choline chloride. These labeled microsomes served both as the enzyme source as well as a source of endogenously labeled substrate. Phospholipase D (PLD) activity was detected with these particles only in the presence of exogenous oleate, its activator. Ca2+ and the ionophore A 23187 inhibit PLD activity of oleate-labeled microsomes. In oleate-labeled particles, besides phosphatidic acid the product of PLD action radioactivity was also detected in diglyceride as a result of resident phosphatidate phosphohydrolase, which hydrolyzed the phosphatidic acid. The phosphatidate phosphohydrolase could not be completely inhibited by KF and propranolol. The release of endogenous fatty acids from labeled phospholipid by a mellitin-stimulated phospholipase A2 also present in these particulates produced minimal stimulation of endogenous PLD. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are hydrolyzed by 50% in the presence of mellitin and 90% of the radioactivity was found in the lyso-compounds. Mellitin and oleate together reduced the radioactivity found in lyso-PC and increased that in lyso-PE.     

Satellite DNA repeat sequence variation is low in three species of burying beetles in the genus Nicrophorus (Coleoptera: Silphidae)

Three satellite DNA families were identified in three species of burying beetles, Nicrophorus orbicollis, N. marginatus, and N. americanus. Southern hybridization and nucleotide sequence analysis of individual randomly cloned repeats shows that these satellite DNA families are highly abundant in the genome, are composed of unique repeats, and are species-specific. The repeats do not have identifiable core elements or substructures that are similar in all three families, and most interspecific sequence similarity is confined to homopolymeric runs of A and T. Satellite DNA from N. marginatus and N. americanus show single-base-pair indels among repeats, but single-nucleotide substitutions characterize most of the repeat variability. Although the repeat units are of similar lengths (342, 350, and 354 bp) and A + T composition (65%, 71%, and 71%, respectively), the average nucleotide divergence among sequenced repeats is very low (0.18%, 1.22%, and 0.71%, respectively). Transition/transversion ratios from the consensus sequence are 0.20, 0.69, and 0.70, respectively.      

A METHOD FOR ISOLATING INTACT MITOCHONDRIA AND NUCLEI FROM THE SAME HOMOGENATE,AND THE INFLUENCE OF MITOCHONDRIAL DESTRUCTION ON THE PROPERTIES OF CELL NUCLEI

1. An improved type of ground glass homogenizer for soft tissues has been described which brings about a high degree of cell disruption and liberation of nuclei without causing appreciable damage to mitochondria. The gentleness and effectiveness of the new homogenizer in respect to isolation of mitochondria have been ascertained by comparing the ATP-ase activities of mitochondria isolated in 0.25 M sucrose solution without pH adjustment using a previous type of homogenizer with those of mitochondria isolated under the same conditions with the aid of the new homogenizer. In these experiments sucrose of 0.25 molarity without pH adjustment has been used in order to maintain the mitochondria in a rather sensitive state so as to make slightly deleterious effects of homogenization readily apparent. 2. A new method is described for the isolation of morphologically intact mitochondria and cell nuclei from the same homogenate. In this procedure the pH of the homogenate in 0.44 M sucrose is maintained at 6.0–6.2 with citric acid during the homogenization. An alternative method employing 0.44 M sucrose plus 0.005 M CaCl₂ is given for the isolation of nuclei from tumor cells. However, the latter method does not produce unaltered mitochondria. 3. The α-ketoglutarate, malate, succinate, and hexanoate oxidases of the "intact" mitochondria isolated in 0.44 M sucrose adjusted to pH 6.0–6.2 with very dilute citric acid as described in this paper have been investigated, and it has been shown that the mitochondria compare favorably to those isolated in 0.25 M sucrose by a previously described method. 4. Mitochondria have been found to contain an enzyme which causes nuclei to lose their ability to form gels in dilute alkali. This enzyme is released from the mitochondria when the latter are disrupted. 5. Some properties of nuclei isolated by the new method have been briefly discussed.     

Cell-Free Transmission and In Vivo Replication of Marek''s Disease Virus

Marek's disease virus recovered from the feather follicle of infected chickens was found to be infectious for chickens in cell-free preparations. The virus replicated in epithelial cells of the germinative layer of the feather follicle epidermis, producing both intranuclear and round or diffuse cytoplasmic inclusion bodies in the infected cells. It was found at this site 2 weeks postinoculation and prior to the development of tumor or other gross lesions. In the nucleus, many naked and a few enveloped herpesvirions were found, whereas the cytoplasm contained predominantly enveloped herpesvirions, which were usually within the cytoplasmic inclusion bodies. Approximately 80% of the extracellular virions were enveloped. Studies with both virulent and avirulent strains of the virus revealed a relationship between virulence, contagiousness, and replication of the virus in the feather follicle.     

Influence of Temperature on Steady-State Growth of Colonies of Pseudomonas fluorescens

Diameters of surface colonies of Pseudomonas fluorescens were observed to increase linearly with time at temperatures from 30 to 0 C.     

Monoclonal antibodies against avian reticuloendotheliosis virus: identification of strain-specific and strain-common epitopes

We report the generation and partial characterization of a panel of 11 monoclonal antibodies (MCA) made against the nondefective strain T reticuloendotheliosis virus (REV). In an enzyme-linked immunosorbent assay (ELISA), nine MCA cross-reacted with both homologous strain T and heterologous strain chick syncytial virus (CS), whereas two MCA were strain specific and reacted with strain T but not with CS. Competitive antibody inhibitory ELISA tests demonstrated that the nine MCA recognized at least two distinct type-common epitopes. By using MCA-mediated immunoprecipitation and polyacrylamide gel electrophoresis analysis, we identified a 62,000 dalton glycoprotein that may contain both type-common epitopes and a 21,000 dalton glycoprotein that contains one of these epitopes. The competitive antibody inhibitory ELISA tests confirmed that the remaining two MCA recognize a strain T-specific epitope. We identified a 54,000 to 72,000 dalton glycoprotein that contains the type-specific epitope. All of the MCA reacted in an ELISA assay with cell-free virus preparations, suggesting that the polypeptides we identified are virion envelope glycoproteins. To identify the nonglycosylated precursor proteins, we treated infected cells with tunicamycin. We found a 48,000 polypeptide that was the nonglycosylated precursor to the 54,000 to 72,000 glycoprotein, and 48,000 and 20,000 dalton proteins that were the nonglycosylated precursors to the 62,000 and 21,000 dalton glycoproteins, respectively. These MCA may be of value in the field. They were able to distinguish in preliminary tests in ELISA between strains T and CS, which were otherwise undistinguishable in assays that made use of conventional polyvalent serum.