Interleukin inhibition by a parasite proteinase inhibitor, taeniaestatin

A proteinase inhibitor, taeniaestatin, isolated from the larval stage of the cestode Taenia taeniaeformis inhibits endogenous IL 2 generation in murine lymphocytes and IL 1 induced proliferation of murine thymocytes in a dose-dependent manner. However, taeniaestatin does not inhibit exogenous IL 2-induced proliferation of an IL 2-dependent cell line at any dose tested. These data indicate that the lack of IL 2 generation may be due in part to inhibition of a crucial cell-associated proteinase subsequent to cellular activation, or the lack of an effective IL 2 signal for differentiation. Our results are novel findings concerning molecular pathways for parasite inhibition of host immune responses, and suggest that selected proteinase inhibitors may be useful in clinical situations in which IL 1 or IL 2 are elevated.     

Use of an androgenized mare as an aid in detection of estrus in mares

A study was conducted over a 2-mo period to compare estrus detection results obtained using an androgenized teaser mare with those obtained with a stallion, using the same group of 10 normally cyclic mares. The teaser mare was androgenized by administration of boldenone undecylenate (500 mg i.m. every 1 to 2 wk), and allowed to run loose with the mare group. Estrus was determined by observation of the group for a 30-min period daily. In the second month of the experiment, a marking harness was used on the androgenized mare to help detect mares mounted when in estrus. Estrous periods detected by each teasing method were 1) first month: stallion, 18; androgenized mare, 5; 2) second month: stallion, 16; androgenized mare, 9. There were no estrous periods detected by the androgenized mare that were not also detected by the stallion. Under these conditions, the androgenized mare was not an adequate estrus detection aid. Also discussed are the successful results of an independent trial on a breeding farm using an androgenized mare as an estrus detection aid.     

Clinical report: Recovery of a degenerating 14-day embryo in the uterine flush of a mare 7 days after ovulation

A 15-mm diameter degenerating embryonic vesicle and a normal, 200-u early blastocyst were recovered in a uterine flush of a mare 7 d after ovulation. From its size, the degenerating vesicle appeared to be 13 to 14 d of age. The mare had been bred during a previous cycle and then treated with prostaglandin 9 days after ovulation. The advanced vesicle that was recovered suggests that a conceptus from the previous cycle continued to grow for about 5 d after prostaglandin administration, and remained in the uterus during estrus, when plasma progesterone concentrations were below 1 ng/ml. From the estimated age of the conceptus, its development stopped at about the time the mare was inseminated. Had this conceptus survived through estrus and insemination, superfetation would have occurred.     

Use of an immediate, qualitative progesterone assay for determination of day of ovulation in an equine embryo transfer program

An immediate, qualitative enzyme-linked immunosorbent assay (ELISA) for progesterone was evaluated for use in determining the day of ovulation in an equine embryo transfer program. Plasma samples were collected from 27 mares from the third day of estrus to the second day of diestrus for 50 cycles. Ovulation was detected by ultrasound examination per rectum. Plasma progesterone concentrations were estimated using the qualitative assay to detect the time of the rise in progesterone after ovulation. Qualitative scores were compared to progesterone concentrations for the same samples as measured by a quantitative ELISA; the correlation between the two methods, expressed as a contingency coefficient, was 0.56. The accuracy of determining day of ovulation using qualitative progesterone results was compared to that achieved using the quantitative assay or detection of the first day of diestrus by teasing. Accuracy in determining day of ovulation +/- 1 d using the three methods was qualitative, 36/50 (72%); quantitative, 44/50 (88%); and teasing, 43/50 (86%). There was a significant difference in accuracy between the qualitative and quantitative progesterone assays (P<0.05).     

The enzymatic activity of proteinase K is controlled by calcium

The fungal proteinase K (EC 3.4.21.14) is a very potent unusually stable member of the subtilisin family. Its X-ray structure determined at 0.15-nm resolution shows two bound Ca2+ ions. Ca1 is in near-ideal pentagonal bipyramidal configuration with Asp200 carboxylate and Pro175 peptide C = O in an apical, and Val177 peptide C = O and four water molecules in an equatorial position, whereas Ca2 displays incomplete octahedral coordination with the carboxylate of Asp260, the peptide C = O of Val16 and the two water molecules. Scatchard analysis of the titration of Ca2+-free proteinase K with Ca2+ yields a single dissociation constant (7.6 +/- 2.5) x 10(-8) M associated with the tightly bound Ca1 whereas Ca2 is so weakly bound that it cannot be titrated. If proteinase K is depleted of Ca2+ by treatment with EDTA, followed by gel filtration, its enzymatic activity drops within 6 h to 20% of its original value, without autolysis. Addition of excess Ca2+ immediately raises the residual activity to 28%, but full activity is not achieved. Removal of Ca2+ triggers a conformational change of the substrate recognition site because there is a direct connection, via secondary structure hydrogen bonds, between the Ca1 binding site and the substrate-recognition site. This is indicated further by circular dichroism and fluorescence-spectroscopic data, and by reversed-phase FPLC, carried out in the presence and absence of Ca2+, but the overall structure of the enzyme is not affected. Depletion of Ca2+ also influences binding of longer peptide inhibitors of the chloromethane type, it increases the rate of autolysis after about 48 h, it reduces the thermal stability (measured by activity tests from 65 degrees C to 46 degrees C), and it enhances the deactivation by 8 M urea which inactivates to only 65%, whereas sodium dodecyl sulfate totally inactivates at a concentration of 12.5%.     

Effect of Monochromatic Light on Proton Efflux of the Blue-Green Alga Anabaena variabilis

Light-induced proton efflux of Anabaena variabilis was found to be biphasic, the second phase being inhibited by the ATPase inhibitor nitrofen (2,4-dichloro-1-[4-nitrophenoxy]benzene). The first, fast phase was triggered by monochromatic light of 707 nanometers, whereas the second, slower phase was not. With 707 nanometers, light, respiratory O₂ uptake was inhibited. Using light composed of two wavelengths (616 and 707 nanometers) a marked enhancement of both O₂ evolution as well as the second phase of proton efflux was observed. The first phase was not enhanced. Thus, phase II is driven by both photosystems. As concluded from the action spectrum phase I is markedly determined by photosystem-I activity. Altogether the data show that two different mechanisms of light-induced proton efflux exist on the cytoplasmic membrane of Anabaena, the slower one being dependent on ATP and linear photosynthetic electron flow.     

The upper cretaceousLacazina limestone in the Basco-Cantabrian and Iberian basins of northern Spain: Cold-water grain associations in warm-water environments

Summary The Upper Santonian to Lower CampanianLacazina Limestone consists of massive, often amalgamated beds of packstones and grainstones which were deposited in a shallow marine environment. The most abundant skeletal components are miliolid foraminifera, echinoderm, bivalve and bryozoan fragments, peloids and sparse red algae. Small, solitary corals only occur sporadically. Hermatypic corals, sponges and green algae are missing. The series which reaches thicknesses between 60 m and 160 m, was sampled at intervals of 0.5 m at five localities. The petrographic features throughout the series are mainly a product of changing depositional energy. The limestones are well cemented. Diagenesis is characterized by a transition from marine phreatic to burial cementation. Syntaxial and blocky calcite cements predominate over early acicular to bladed and microgranular cements. The faunal association within theLacazina Limestone exhibits features typical for temperate water i.e.foramol carbonates. On the other hand, oxygen (δ¹⁸O =-1.7 to −6.3 ‰ PDB) and carbon (δ¹³C to 3.0‰ PDB) isotope values of diagentically unaltered bivalve shells indicate warm surface waters corresponding better to the palaeogeographical situation of theLacazina Limestone. Nutrient-surplus is proposed as a limiting factor preventing the development of reefs and finally ofchlorozoan sediments. In the sense of sequence stratigraphy, theLacazina Limestone is interpreted to contain transgressive and highstand systems tracts. This interpretation fits well into theHaq-Vail-curve. The series shows no visible high-frequency cyclicity in the field. Several cycles were found by means of principle component analysis and spectral analysis. Their relationships to the Milankovitch spectrum are discussed. The ammonite fauna of the unit and of preceding sediments (late Coniacian to early Campanian) is described and some inoceramids are figured. They permit—for the first time—the exact dating of theLacazina Limestone in the Basco-Cantabrian Basin (BCB) and throw light on a prominent faunal change at the Coniacian/Santonian boundary. The Cenomanian to Coniacian ammonite faunas which were dominated by endemic Tethyan pseudoceratitic faunas are replaced by cosmopolitan species dominated by Madagascan elements. This drastic change permits speculations about the installation of a new oceanic current system in the Santonian.