Evolution of the lipoprotein gene in the enterobacteriaceae. Cloning and DNA sequence of the lpp gene from Proteus mirabilis

We cloned the lipoprotein gene from Proteus mirabilis and determined its DNA sequence. Comparison with the lpp genes from Escherichia coli, Serratia marcescens, Erwinia amylovora and Morganella morganii revealed several unique features of the evolution of the lpp gene in the Enterobacteriaceae and enabled us to establish phylogenetic relationships between these bacteria.     

Enkephalin pseudopeptides: resistance to in vitro proteolytic degradation afforded by amide bond replacements extends to remote sites

Five analogs of leucine enkephalin containing the CH2S group as an amide bond replacement were evaluated with respect to resistance toward degradation by human serum in an HPLC-based assay using both ultraviolet and electrochemical detection. Analogs with the modification at the 1-2, 2-3, 3-4, or 4-5 peptide linkages demonstrated half-lives of 118, 85, 134, and 318 min vs. 12 min for the parent peptide. A pseudopeptide analog with additional D-Ala2 protection had a half-life of greater than 1000 min, while the potent [D-Ala2]-leucine enkephalin analog showed approximately a 10-fold increase in stability. The significant increase in stability for a compound with protection only at the C-terminus suggests that serum enzymes may have greater specificity toward backbone changes than previously realized.     

60-Hz electric fields: detection by female rats

Female rats were trained to detect a vertical, 60-Hz electric field using the same apparatus and procedure we used previously to study behavioral detection of the field by male rats. Each rat was trained individually to press a lever in the presence of the field and not to press in its absence. Correct detections occasionally produced a food pellet. The probability of detecting the field increased as field strength increased. The threshold of detection--ie, the field strength required for detections at a probability of 0.5 after correction for errors--varied among rats between 3 and 10 kV/m. Behavioral detection by female rats was indistinguishable from that by male rats.     

Evaluation of the Subhuman Primate Pregnancy Test Kit for the detection of early pregnancy in the rhesus monkey (Macaca mulatta)

The performance of The Subhuman Primate Pregnancy Test Kit was evaluated for routine detection of early (days 19-21) pregnancy in the rhesus monkey. Out of 123 confirmed matings, 19 resulted in pregnancy. In the pregnant animals the kit had an accuracy of 73.7%. In the nonpregnant females the accuracy was higher, 88.5%. False positives were encountered in ovariectomized females as well as adult intact males.     

A versatile bacterial enzyme: l-methionine γ-lyase

The properties and application of l-methionine γ-lyase [methioninase, l-methionine methanethiol-lyase (deaminating), EC 4.4.1.11], a pyridoxal 5′-phosphate enzyme, purified from Pseudomonas putida and Aeromonas sp. are presented. The enzyme has multicatalytic functions: it catalyses α,γ-elimination and γ-replacement reactions of l-methionine and its analogues (e.g. ethionine, homocysteine, O-acetylhomoserine and selenomethionine), α,β-elimination and β-replacement reactions of l-cysteine and its analogues (e.g. S-methylcysteine, O-acetylserine and Se-methylselenocysteine), deamination and γ-addition of vinylglycine, and deuterium labelling at the α and β positions of l-methionine and other straight-chain l-amino acids. These reactions are applicable to the synthesis of various optically active sulphur and selenium amino acids, preparation of deuterium or tritium labelled l-amino acids, and determination of sulphur amino acids. In addition, the enzyme shows potent anti-neoplastic activity.     

Risk of predation,hydrodynamic efficiency and their influence on school structure

Synopsis Laboratory studies were conducted on 15 schools of blackchin shiners, Notropis heterodon, to determine if they altered their structure in response to changing environmental demands. The hypothesis tested was that fish schools should sacrifice a flat, hydrodynamically efficient structure in favour of an unobstructed visual field in the presence of a predator by staggering in the vertical plane. Ten schools were exposed for two weeks to a simple environment with only a current. For the next two-week period a predator was added. Five control schools were exposed to the simple environment for both two-week periods. Six of the ten treated schools increased their staggering in the vertical dimension as predicted while none of the control schools changed. This result was suggestive that hydrodynamic advantages were sacrificed. Respirometer experiments indicated these fish were capable of achieving some hydrodynamic benefits from schooling but these benefits may be a function of fish size.     

Electrolysis-mediated irreversible inactivation of lipoxygenase directed toward electroaffinity labelling

Irreversible inhibition of soybean lipoxygenase-1 (SL-1) was accomplished via a controlled potential oxidative electrolysis of 1,5-dihydroxynaphthalene (1,5-DHN) at +0.8 V vs SCE. The inactivation of SL-1 with this known inhibitor was greatly enhanced under these electrolytic conditions to which the enzyme itself was stable. Electrolyses were run at 0 degree C in a 0.05 M phosphate buffer, pH 7.0, using graphite cloth electrodes. The rate of inactivation was observed to be limited by and dependent on the anodic oxidation of 1,5-DHN. The non-oxidizable (at this potential) inhibitor indomethacin was shown to protect the enzyme from irreversible inactivation, however, an external nucleophile (2-mercaptoethanol) had little effect. These initial studies support the capability of such electrochemical methods for the site-specific covalent modification (affinity labelling) of lipoxygenase, and perhaps other enzymes.     

Catechol-O-methyltransferase: A method for autoradiographic visualization of isozymes in Cellogel

An electrophoretic procedure for separating the molecular forms of catechol-O-methyltransferase in cellulose acetate gel is described; the zones of enzyme activity were revealed by autoradiography. The electrophoretic patterns of the enzyme in several tissues and cell lines derived from four different species are presented.This investigation was supported by Grant 500.6/Ric. 70/1981 from the Italian Ministry of Health and by the Italian Ministry of Education. We are grateful to Dr. M. Castagnola for useful advice and help with thin-layer chromatography.     

Striated ciliary root-golgi association in branchial crown epithelial cells ofOwenia. Visualization of Ca2+-binding sites and ATPase activities

Summary Striated Ciliary Roots (SCRs), about 3 m long, are attached to the basal bodies of branchial crown ciliated epithelial cells ofOwenia. These SCRs appear to consist of 5–7-nm diameter filaments organized in a cross-striation pattern with an apparent variable periodicity of 50 to 80 nm. The most exciting observation emerging from this study is the constant and conspicuous close spatial relationship between SCRs and fairly well developed Golgi apparatus. By enhancing contrast and preservation of cell components, the OsFeCN postfixation-staining of material prefixed in glutaraldehyde in the presence of calcium has revealed some fine-structural details within the SCR-Golgi Association. By means of the calcium precipitation method, with antimonate or oxalate in conjunction with X-ray microanalysis, we have identified calcium within SCR dark bands and SCR-associated Golgi bodies. The ability to bind calcium makes the Golgi apparatus a likely candidate for Ca²⁺ regulation of putative contraction of the SCRs and/or ciliary motility. The slight period variability measured in the SCRs and cytochemical localization of Mg²⁺, Ca²⁺-dependent ATPase activities associated with cross striations support the view that theOwenia SCRs may be contractile organelles.The striking and specific close structural association between the Golgi apparatus and the SCR showing Ca²⁺-binding capabilities suggests that some sort of Ca²⁺-mediated functional relationship between these organelles may exist.Abbreviations SCR striated ciliary root - OsFeCN method osmium tetroxide-ferricyanide method - EDTA ethylenediamine tetraacetic acid - EGTA ethyleneglycol-bis-(-aminoethyl ether) N,N-tetraacetic acid - ATP adenosine 5-triphosphoric acid - ATPase adenosine triphosphatase - ASW artificial sea-water     

Breeding vervet monkeys in a closed environment

A breeding group of vervet monkeys produced 95 offspring over five years. Fetal wastage for 114 pregnancies was 16.7%. Uterine sizes were recorded for 103 pregnancies in various stages of gestation. This enabled diagnosis of pregnancy, estimation of stage of gestation, and prediction of parturition to within two weeks. Detailed observations were made on dental eruption, pelage development, and growth of 57 infants.