Identical Counterparts Research Articles

NMR solution structure of the recombinant tick anticoagulant protein (rTAP), a factor Xa inhibitor from the tick Ornithodoros moubata

The solution structure of the recombinant tick anticoagulant protein (rTAP) was determined by 1H nuclear magnetic resonance (NMR) spectroscopy in aqueous solution at pH 3.6 and 36°C. rTAP is a 60-residue protein functioning as a highly specific inhibitor of the coagulation protease factor Xa, which was originally isolated from the tick Ornithodoros moubata. Its regular secondary structure consists of a two-stranded antiparallel β-sheet with residues 22–28 and 32–38, and an α-helix with residues 51–60. The relative orientation of these regular secondary structure elements has nearly identical counterparts in the bovine pancreatic trypsin inhibitor (BPTI). In contrast, the loop between the β-sheet and the C-terminal α-helix as well as the N-terminal 20-residue segment preceding the β-sheet adopt different three-dimensional folds in the two proteins. These observations are discussed with regard to the implication of different mechanisms of protease inhibition by rTAP and by Kunitz-type protein proteinase inhibitors.

Identical Superdeformed Bands and Quantized Spin Alignments in A ~ 190 Region11The project supported by the Doctoral Programme Foundation of Institution of Higher Education of China, National Natural Science Foundation of China, and the Science Foundation of Peking University.

Identical superdeformed bands exist extensively in the A ~ 190 region. With a few exceptions, almost all the superdeformed bands observed have their identical counterparts, supporting the concept of the quantized spin alignment. A likely explanation of the systematics of the superdeformed bands within the framework of particle-rotor model with pseudo-spin symmetry is presented.

Identity between the placental protein PP10 and the specific plasminogen activator inhibitor of placental type PAI-2

The highly specific plasminogen activator inhibitor of placental type, PAI-2, occurs in the placenta in a low molecular mass form of 46.6 kDa, and in pregnancy plasma in a (possibly glycosylated) high molecular mass form of 60 kDa. Extensive knowledge is available about the functional properties of PAI-2 as a plasminogen activator inhibitor and about its molecular biology and regulation. Of the several placenta proteins (PP) isolated, one of them, PP10, has a molecular mass of 48 kDa and its occurrence in malignancy and in complications during pregnancy has been the topic of a number of studies, though its properties and physiological significance are unknown. The present findings constitute evidence of immunological identity between PP10 and PAI-2. The sections of the amino acid sequence of PP10 analysed here were found to have identical counterparts in the sequence of the low molecular mass form of PA1-2, but in several preparations PP10 was found to occur in an inactive two-chain form due to cleavage of an Arg-Thr bond, the two peptide chains being linked to each other by a disulphide bridge. The cleavage site is identical to that observed in the reaction between PAI-2 and urokinase. The results make it possible to coordinate and correlate the findings of many separate studies and our own observations on PP10 and PAI-2.

Phenotypic selection and characterization of mutant alleles of a eukaryotic DNA topoisomerase I.

We have developed a simple, effective genetic screen for mutant alleles of eukaryotic DNA topoisomerase I that manifest severely depressed or complete loss of enzymatic function. The screen is based on the extreme toxicity of vaccinia topoisomerase expression in the Escherichia coli lysogen strain BL21(DE3) and is notable for its ease in distinguishing nonsense mutations (that result in truncated proteins) from missense mutations. The power of the method is evinced by our observation that 100% of the candidate alleles identified in the screen were ultimately found to have single-base changes at the DNA level that result in amino acid substitutions at the protein level. By mutagenizing plasmid DNA in vitro with hydroxylamine and applying this phenotypic screen, we have isolated five distinct single amino acid substitution mutants, each of which shows a biochemical phenotype, that is, greater than or equal to 90% reduction in specific DNA relaxing activity of the mutant protein relative to wild type. The amino acids thus implicated in topoisomerase function have identical or related counterparts at homologous positions in the topoisomerases from yeast and man. The same genetic screen has been applied to the selection of temperature-sensitive alleles of the vaccinia topoisomerase, leading to the isolation of two additional single-hit mutant alleles that display a temperature-sensitive growth phenotype in E. coli BL21(DE3). By broadening our mutagenesis procedures, we expect to generate a comprehensive map of vaccinia topoisomerase function and primary protein structure that should have direct application to eukaryotic cellular enzymes. Our methodology should be applicable to the selection of missense and conditional mutant alleles in other genes whose expression in bacteria is toxic.

Somnogenic activity of O-acetylated and dimeric muramyl peptides.

Slow-wave sleep-promoting factors in brain and urine were identified as muramyl peptides (MPs), the building blocks of bacterial cell wall peptidoglycan. In this study, structural variations of MPs that occur naturally in bacterial peptidoglycan were investigated for somnogenic activity. Monomeric and dimeric MPs were isolated and purified from Neisseria gonorrhoeae and Actinomadura sp. strain R39. The structures of these MPs were verified by fast atom bombardment mass spectroscopy and tandem mass spectroscopy. After intracerebroventricular administration of MPs, electroencephalograms and brain temperatures of rabbits were recorded for 6 h and were analyzed to determine durations of slow-wave sleep, rapid-eye-movement sleep, and wakefulness. The 6-O acetylation of muramic acid enhanced the somnogenic effects of certain monomeric MPs relative to their non-O-acetylated (but otherwise identical) counterparts. Two monomeric MPs containing an unsubstituted amide (i.e., Iso-Gln) were inactive, thus confirming previous results showing that amidation of a variety of MPs can block somnogenic activity. Two peptide-cross-linked MP dimers tested had no effect on slow-wave sleep, although a third peptide-cross-linked MP containing a 1,6-anhydro muramyl end on one of its monomeric subunits, a structure that enhances somnogenic potency of un-cross-linked monomers, was somnogenic. Two dimers connected by glycosidic bonds and containing an Iso-Gln moiety were inactive. Two other glycosidically linked dimers that also contained an Iso-Gln moiety, but were of lower molecular weight, were somnogenic. In summary, 6-O acetylation of muramic acid in somnogenic MPs enhances activity, and as a class, peptide-linked dimeric MPs tend to be less active than their constituent monomers.

Basic proline‐rich proteins of murine parotid glands

Five major basic polypeptides with characteristics typical of proline-rich proteins, accumulated in parotid glands after long term isoprenaline treatment of Balb C mice. They were studied by two-dimensional gel electrophoresis and designated B1 degree, B2' degrees, B2 degrees, B3 degrees and B4 degrees on the basis of pI-dependent mobility. They were not observed in the glands of normal mice and were precipitated when glands were homogenized in 10% trichloroacetic acid unlike the three isoprenaline-induced proline-rich proteins of murine parotid glands reported previously. Isoprenaline induced six proline-rich in vitro translation products which were absent normally. Four of these species had pI-dependent mobilities almost identical to B1 degree, B2 degrees, B3 degrees and B4 degrees, indicating not only precursor/product relationships, but also that isoprenaline induced the accumulation of the proteins by regulating the mRNA. Identical salivary counterparts of the basic glandular proline-rich proteins were not detected whereas a series of smaller and more basic isoprenaline-induced polypeptides were observed in saliva (major speices B1s-B4s). The glandular proline-rich proteins were secreted from parotid tissue in vitro and the data indicate that proline-rich proteins are synthesised as precursors and processed into salivary form in the parotid glands after secretion. The relationships between the B-type in vitro translation products, parotid gland precursors and salivary proteins were also confirmed immunologically.

Nonhuman Primate Models for Human Disease

The value of nonhuman primates as models for a variety of human diseases is well documented. These species have been used extensively during the past 25 years or so as models for a variety of bacterial, viral, and parasitic diseases, either as naturally occurring or experimentally induced infections. They are often the only nonhuman species susceptible to experimental infection with agents of human disease. Spontaneous diseases of nonhuman primates are often comparable to human diseases, and with the continued long-term maintenance of nonhuman primates in the laboratory as well as in domestic breeding colonies, it is reasonable to assume that additional disease models will be discovered. Such models may include degenerative diseases, diseases and/or lesions associated with the aging process, and genetic diseases. In this article we have reviewed four spontaneous diseases and one induced disease that have essentially identical counterparts in humans. Three of these are bacterial diseases that currently cause severe and sometimes fatal infections in humans; one is a degenerative disease that is usually progressive and fatal in humans, and one is possibly a genetic disease for which there is currently no animal model. The clinical and pathologic similarities between these nonhuman primate diseases and their human counterpart make these nonhuman primate diseases potentially valuable models for further studies on the etiology, pathogenesis, and treatment of these serious and often fatal human diseases.

Decisions under imperfect knowledge: The certainty equivalence theory as an alternative to the von Neumann-Morgenstern theory of uncertainty

This paper offers a modified version of the certainty equivalence (CE) theory of utility for uncertain prospects and a new set of axioms as its basis. It shows that the CE and the von Neumann-Morgenstern (NM) approaches to uncertainty are opposite in spirit: The CE approach represents a flight from the world of uncertainty to the rules of certainty while the NM approach represents a flight from the world of certainty to one of uncertainty. The two approaches differ even in their treatment of compound prospects and their actuarially identical simple counterparts.

Identification and localization of glucagon-related peptides in rat brain.

Immunochemical and immunocytochemical techniques have been used to identify and characterize glucagon-related peptides of the rat central nervous system. These peptides show immunoreactivity with antiglucagon sera directed towards the central portion of the hormone, but not with antisera specific for the free COOH terminus of glucagon. Highest concentrations were found in hypothalamus (6.1 +/- 1.6 ng/g wet weight) although lower amounts (approximately 2 ng/g) were found in cortex, thalamus, cerebellum, and brain stem. Gel filtration of brain extracts revealed at least two immunoreactive forms, which have molecular weights of about 12,000 and 8000. Both peptides had radioimmunoassay dilution curves parallel to the curve for glucagon and both had identical counterparts in extracts of rat intestine. Digestion of the brain and intestinal peptides with trypsin plus carboxypeptidase B released the immunoreactive COOH-terminal tryptic fragment of pancreatic glucagon from these larger forms. Immunocytochemical studies using antiglucagon serum and peroxidase-antiperoxidase staining identified glucagon-like material in neuronal cell bodie and processes in the magnocellular portion of the paraventricular nucleus, as well as in scattered cells in the supraoptic nucleus and in fibers in the median eminence. These results suggest that glucagon-containing peptides that have undergone the intestinal type of posttranslational modification are present in neuronal cells of the rat hypothalamus.

An electrophoretic study of proteins of the ovary, fat body, and haemolymph in the migratory grasshopper, Melanoplus sanguinipes

Abstract Electrophoretic separation of saline extracts from the ovary revealed 14 proteins. Twelve proteins were detected in the fat body, of which seven had electrophoretic mobilities identical to those in the ovary. Similarly, eight of 16 proteins in the haemolymph of vitellogenic females ahad electrophoretically identical counterparts in the ovary. As these proteins accumulate in the haemolymph of ovariectomized females, the findings suggest that most yolk proteins are synthesized in the fat body. Although most female haemolymph proteins are present in males, two of the predominant yolk protiens are absent and represent female-specific proteins. Although certain proteins accumulate in the haemolymph of allatectomized females, the major ovarian proteins are absent or present in low concentrations. However, 48 hr after allatectomized females are treated with a juvenile hormone analogue, the haemolymph protein pattern resembles that of a normal female. This suggests that the corpora allata stimulate the synthesis of female-specific and other vitellogenic proteins. The median neurosecretory cells (mNSC) are also necessary for synthesis of female-specific proteins. Furthermore, proteins which are present in allatectomized females are absent in mNSC-cauterized insects suggesting that the mNSC stimulate general protein synthesis.

Upper Mesozoic flysch of Tierra del Fuego and South Georgia Island: A sedimentologic approach to lithosphere plate restoration

The South Georgia Island segment of the North Scoria Ridge is interpreted as having once been adjacent to Tierra del Fuego, South America. The upper Mesozoic graywackes, mudstones, and tuffs of South Georgia (Cumberland Bay and Sandebugten strata) and Tierra del Fuego (Yahgan Formation and Tekenika Beds) are the infill of a marginal basin that formed between the South American continent and an active calc-alkalic arc. The former arc site is now occupied by the Patagonian batholith; ophiolites represent the former basin sea floor. Sediment gravity flow fabrics, sedimentary structures, and bedding styles and relatively deep-water trace fossils ( Phycosiphon , Helminthopsis , Taenidium , Zoophycos , Chondrites , Scalarituba ?, Lophoctenium ?) indicate deposition on submarine fans. Paleocurrent and petrographic analyses indicate bilateral infilling of the basin. The only known possible sources for the Sandebugten sandstones are silicic volcanic and interbedded sedimentary rocks of the Jurassic Tobifera Formation of South America; this evidence indicates former juxtapositioning of South Georgia and Tierra del Fuego. The Sandebugten-type sandstones and the Jurassic volcanic rocks have abundant quartz and plagioclase, uncommon potassic feldspar, and essentially no pyroxene and amphibole. Lithic fragments in these sandstones have identical counterparts in the Jurassic volcanic and sedimentary rocks. The Yahgan and Cumberland Bay clastic rocks were eroded chiefly from calc-alkalic volcanic rocks positioned south of their depositional areas. The latter sandstones are made up dominantly of andesite and dacite tuff and flow fragments. Plagioclase is common; quartz, ferromagnesian minerals, and mafic volcanic fragments are uncommon. Basin closure and deformation occurred during the Late Cretaceous Andean orogeny when the rocks were metamorphosed to prehnite-pumpellyite grade. South Georgia was translated relatively eastward, probably as the result of collision of the Drake Passage spreading zone with the continent during Oligocene to Miocene time.

INFLUENCE OF SOURCE OF WHEAT CYTOPLASM ON THE SYNTHESIS AND PLANT CHARACTERISTICS OF HEXAPLOID TRITICALE

Reciprocal F1 triticale hybrids (× Triticosecale Wittmack) produced from crosses between primary 6x amphiploids (C1) were synthesized that differed only in their source of cytoplasm. One member of each reciprocal pair possessed hexaploid (6x) wheat cytoplasm (Triticum aestivum L. em Thell), the other, tetraploid (4x) wheat cytoplasm (T. turgidum L.). Comparisons of agronomic and reproductive behavior were made between members of reciprocal F1 pairs. Initial embryo development, embryo survival in vitro, and survival of F1 wheat-rye hybrids were 10, 105, and 127% higher respectively when the female parent possessed 6x as compared with 4x wheat cytoplasm. Similarly, F1 amphiploids with 6x cytoplasm were 3.0% taller and developed 25.0% more fertile tillers than their genetically identical counterparts with 4x cytoplasm. Spike morphology and floret number were not found to be influenced by source of cytoplasm. As current triticale procedures require the synthesis of new wheat-rye amphiploids for the introduction of genetic variability, it is suggested that the utilization of 6x wheat cytoplasm would enhance such a program as well as improve the agronomic performance of triticales so synthesized.