Separation of Legionella pneumophila proteases and purification of a protease which produces lesions like those of Legionnaires' disease in guinea pig lung

Six discrete protease activities were recovered from the supernatant broth of Legionella pneumophila cultures by ion-exchange chromatography. One of these demonstrated in vitro activity against collagen, casein and gelatin. When administered into the lungs of guinea-pigs this protease elicited lesions which were pathologically similar to those seen in clinical and experimentally induced Legionnaires' disease.     

Changes in ovine conceptus and endometrial function following asynchronous embryo transfer or administration of progesterone

The secretory protein profile from conceptuses collected from naturally mated ewes on Days 10, 12, 14, and 16 was characterized by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and fluorography. The presence of the anti-luteolysin ovine trophoblast protein-1 (oTP-1) in culture medium from Day 10 conceptuses was confirmed by fluorography, Western blotting, and radioimmunoassay (RIA). On each of the days studied, oTP-1 was the dominant secretory protein, and was secreted in increasing quantities as pregnancy progressed. In a second experiment, Day 6 embryos were transferred to either Day 6 (SR) or Day 4 (AR) recipients. Three mated ewes (P) received daily injections of 50 mg progesterone on Days 4-9. Controls consisted of 2 groups of pregnant ewes (D8 and D10). Conceptuses and ipsilateral endometrium were collected 4 days following transfer of conceptuses to SR and AR ewes, on Day 10 in P and D10 ewes, and on Day 8 in D8 ewes. Conceptus volume was estimated upon recovery from the uterus. Tissues were cultured with 35S-methionine, and the medium was analyzed for total and trichloroacetic acid-precipitable radiolabeled proteins. Levels of specific endometrial secretory proteins were determined after protein separation by 2D-PAGE and estimation of the radioactivity associated with discrete radiolabeled proteins on fluorographs. The concentration of oTP-1 in conceptus culture medium was estimated by RIA. Thirty endometrial proteins were investigated. All 30 proteins were present in endometrial cultures from SR, AR, D10, and P ewes, but 13 proteins were absent from D8 ewes. Levels of three proteins were higher in AR compared to D8 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Inactivation of human alpha-1-antitrypsin by a tissue-destructive protease of Legionella pneumophila

Three extracellular proteases produced by Legionella pneumophila during growth in liquid medium were examined for their effects on human alpha-1-antitrypsin (alpha-1-AT). One of these proteases, tissue-destructive protease (TDP) destroyed completely the trypsin-inhibitory capacity of alpha-1-AT at protease: inhibitor molar ratios down to 0.002:1. After inactivation by TDP, the Mr of alpha-1-AT was reduced by 5000 in SDS-PAGE. This suggested that inactivation entailed only limited cleavage.     

Cytogenetics of human sperm: meiotic segregation in two translocation carriers.

Meiotic segregation products were studied in sperm from two men heterozygous for the reciprocal translocations t(8;15)(p22;q21) and t(3;16)(p23;q24). A total of 226 and 201 sperm complements, respectively, were analyzed. In each translocation, 63% of complements were unbalanced, and alternate and adjacent 1 percentages were similar. The 3:1 segregation frequencies produced by the two translocations were 3.5% and 5.0%.     

The metabolism of macromolecules during the differentiation of myxamoebae of the cellular slime mould Dictyostelium discoideum containing different amounts of glycogen

1. Methods of obtaining myxamoebae of Dictyostelium discoideum strain Ax-2 (ATCC 24397) with glycogen contents in the range 0.05-5mg of glycogen/10(8) cells are described. The changes in cellular glycogen, protein and RNA content during the differentiation of such myxamoebae were determined. 2. Myxamoebal glycogen is not conserved during differentiation and gluconeogenesis may occur even in cells that contain a large amount of glycogen initially. 3. There is a marked net loss of cellular protein and RNA during differentiation and associated with this there are also marked decreases in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 4. During the early stages of development some protein and pentose(s) are excreted, but this cannot account for the decreased cellular content of protein and RNA. 5. There is a linear rate of production of NH(3) during development, and oxidation appears to be the fate of the major portion of the degraded protein and RNA. 6. However, provision of an alternative metabolizable energy source (glycogen) has little effect on the rate or extent of protein or RNA breakdown or on the changes in the sizes of the intracellular pools of amino acids, acid-soluble proteins and pentose-containing materials. 7. It is concluded that during development there is a requirement for the destruction of specific RNA and protein molecules for reasons other than the provision of oxidizable substrates. 8. The kinetic model of Wright et al. (1968) is discussed in relation to these changes in macromolecular content.     

Changes in leaf ultrastructure and carbohydrates inArabidopsis thaliana L. (Heyn) cv. Columbia during rapid cold acclimation

Summary We studied cell ultrastructure and carbohydrate levels in the leaf tissue ofArabidopsis thaliana L. (Heyn) cv. Columbia during rapid cold acclimation. Freezing tolerance of the leaves from 26 day old plants was determined after 48 h and 10 days at 4°C. Acclimation treatment of 48 h decreased the lethal freezing temperature from –5.7°C to –9.4°C. Freezing tolerance was not altered further by acclimation at 4 °C for 10 days. Ultrastructural changes in the parenchyma cells were evident after 6 to 24 h of cold acclimation. The plasma membrane showed signs of extensive turnover. Evidence of membrane invaginations and sequestering of membrane material was observed. In addition, numerous microvesicles, paramural bodies, and fragments of endoplasmic reticulum were noticed in the vicinity of plasma membrane. Modifications in the structure of cell membranes were evident after 5 days of exposure to low temperature. Small, darkly stained globules were seen on the plasma membrane, tonoplast, chloroplast envelope membrane, mitochondrion outer membrane, dictyosome cisternae membrane, and microvesicle membrane. As far as we are aware, this type of membrane modification has not been described previously in plant cells exposed to low temperature. We propose to call these structures membraglobuli. Acclimation treatment also increased the concentrations of soluble sugars and starch. These observations suggest that cold acclimation inA. thaliana induces changes in both plasma membrane properties and carbohydrate composition.