Comparative gastrointestinal morphology of the Kori bustard and secretary bird

Two secretary birds and three Kori bustards were studied to determine differences between their body size and gastrointestinal morphology. Body measurements were made on captive, live birds and gastrointestinal measurements on fresh postmortem specimens. For predator species, such as the Kori bustard and secretary bird, body size is a function of their ability to capture and destroy prey. While the secretary bird was clearly the taller of the two species, superior body weight, wing length, and therefore body size was noted for the Kori bustard. The size and length of the gastrointestinal tract varied between species. The secretary bird had the shorter, less complex digestive tract, with a foregut well adapted for consumption of large quantities of flesh. The large intestine was devoid of ceca. The gastrointestinal tract of the Kori bustard was markedly different from that of the secretary bird. The foregut was less complex and the large intestine possessed large, voluminous ceca.     

The sesquiterpene lactone hymenoxon acts as a bifunctional alkylating agent

Hymenoxon, a toxic sesquiterpene lactone found in bitterweed, bound deoxyguanosine in a cell free system and formed adducts with guanine residues in cellular DNA. The reactive dialdehyde form of hymenoxon formed stable Schiff base products with deoxyguanosine which were separable from unreacted hymenoxon and deoxynucleosides by reverse phase high pressure liquid chromatography. Hymenoxon adducts which eluted as a single impure peak from the octadecylsilane column separated on amino and diphenyl-bonded phases with 10% methanol. Tritiated nucleoside adducts were isolated and purified from CFW mouse sarcoma cells treated with hymenoxon. Proton nuclear magnetic resonance spectra of purified hymenoxon-deoxyguanosine adducts revealed a loss of signals for hydroxyl groups in the bishemiacetal of hymenoxon. ¹³C-nuclear magnetic resonance spectra revealed that the major adduct has 35 carbon atoms, indicating an interaction of at least two guanine residues per hymenoxon molecule and suggesting that hymenoxon may cross-link DNA. Sedimentation analysis of treated DNA further showed that DNA cross-linking by hymenoxon (30 µg/ml) was equivalent to that of a known cross-linking agent, mitomycin C (7.5 µg/ml). Hymenoxon was more cytotoxic to DNA cross-link repair-deficient Chinese hamster ovary cell mutants than to repair proficient strains. These data combine to indicate that hymenoxon acts as a bifunctional alkylating agent which cross-links DNA in mammalian cells.CHO Chinese hamster ovary - HYM hymenoxon - MMC mitomycin C - NMR nuclear magnetic resonance - PBS phosphate buffered saline     

Purification and properties of two phospholipid transfer proteins from yeast

Several intracellular proteins of low and intermediate molecular weights have been isolated from a variety of mammalian and plant tissues that possess an ability to catalyze the transfer or exchange of intact phospholipid molecules between different membrane systems. The soluble cytosolic fraction of the yeast Saccharomyces cerevisiae also contains phospholipid transfer activity that varies with both the state of cellular growth and the type of metabolic carbon source. This activity is protein in nature and very unstable, and requires powerful separation techniques for its purification. Here we report the isolation and characterization of two phospholipid transfer proteins from yeast, one of which we believe represents a partial proteolytic product of the other. The two proteins were purified to near homogeneity through a combination of dye-ligand and high performance ion-exchange chromatographic techniques. Transfer protein I (TP-I) is eluted at a lower ionic strength from an anion-exchange column than transfer protein II (TP-II), which reflects the difference in their isoelectric points; TP-I has a pI of 6.3, while that for TP-II is 6.1. Both species have the same apparent molecular weight of 33,400 and virtually identical substrate specificities. The order of the relative rates of phospholipid transfer are phosphatidylcholine greater than phosphatidylethanolamine greater than phosphatidylinositol greater than phosphatidylserine.     

Immunolocalization of alpha and beta chains of human chorionic gonadotropin,placental lactogen and pregnancy-specific beta-glycoprotein in term placenta by a touch preparation method

Summary Touch preparations of human placenta yield cells retaining antigenic reactivity to immunoperoxidase stains for and chains of human chorionic gonadotropin, placental lactogen, and pregnancy-specific glycoprotein. This method is a rapid and simple alternative to conventional frozen and paraffin-embedded sections for detection of placental peptides.     

Immunohistochemical heterogeneity of alpha-tubulin in human epithelia revealed with monoclonal antibodies

Summary Four monoclonal antibodies raised to alpha subunit of pig brain tubulin (TU-01, TU-02, TU-03, TU-04) were used to study immunohistochemical heterogeneity of alpha tubulin in human epithelia. Selective reactivity was detected in the skin and trachea/bronchi, whereas all other epithelia investigated reacted uniformly with all four monoclonal antibodies. In the skin TU-01 reacted very strongly with all layers except the basal layer; TU-02 reacted strongly with granular layer and was unreactive or only weakly reactive with others; TU-03 reacted very strongly with basal layer and weakly to moderately with superficial layers; TU-04 reacted strongly with the granular layer of epidermis and was unreactive with other layers. In the trachea and major bronchi TU-01 reacted with the entire epithelial layer; TU-02 reacted only with superficial layer; TU-03 reacted with superficial and basal layer; TU-04 reacted only with superficial layer. Different staining patterns obtained with these four monoclonal antibodies indicate that there is immunohistochemical heterogeneity of alpha tubulin in some but not all normal human epithelia.     

Plasmid-encoded copper resistance and precipitation by Mycobacterium scrofulaceum.

A copper-tolerant Mycobacterium scrofulaceum strain was able to remove copper from culture medium by sulfate-dependent precipitation as copper sulfide. Such precipitation of copper sulfide was not observed in a derivative that lacks a 173-kilobase plasmid. In addition, the plasmid-carrying strain has a sulfate-independent copper resistance mechanism.     

Effect of nutritional insufficiency on cell proliferation in the matrix zones of the cerebellar anlage in mice

The work has been performed on 62 CBA mice. In the ventricular zone and in the external granular layer of the cerebellar anlage of embryos (13-17 days of the intrauterine development) mitotic index, labelled nuclei index, part of labelled mitoses have been counted. Parameters of the mitotic cycle of the matrix cells have been calculated by means of the graphic method. The proliferative pool value has been calculated. At malnutrition the cerebellar anlage structure retards in its maturation from the norm. For the matrix zones of the cerebellar anlage, higher indices of the proliferative activity are specific. At the same time, duration of the mitotic cycle of the matrix cells increases by 15-17%. It is possible, that retardation of histogenesis of the mouse cerebellar anlage, when developing under conditions of alimentary insufficiency depends on decreased rate of cell proliferation, as a result of prolonged mitotic cycle of the matrix cells.     

The effect of feeding high corn oil on fatty-acid-binding-protein isolated from rat liver

Fatty-acid-binding-protein isolated from liver of rats receiving normal or high fat diet was studied by three different methods. The effect of high fat diet on the thermal stability of the protein was determined employing differential scanning calorimetry. Fatty acids have a stabilizing effect on the thermal stability of the protein. In order to determine the relative binding affinity of native and delipidated protein a Sephadex G-50 assay was employed using [1-14C] oleate as ligand. The delipidated protein exhibited greater binding of oleate than did the native material. Increases in the transfer of oleic acid from rat liver microsomes to egg lecithin liposomes in vitro were also observed when protein obtained from both sources were delipidated. The results suggest that high corn oil diet would modify the properties of fatty-acid-binding-protein in the uptake and cytosolic transport of long-chain fatty acids.     

Effect of beta-hydroxybutyrate and acetoacetate on insulin and glucagon secretion from perfused rat pancreas

To elucidate the physiological significance of ketone bodies on insulin and glucagon secretion, the direct effects of beta-hydroxybutyrate (BOHB) and acetoacetate (AcAc) infusion on insulin and glucagon release from perfused rat pancreas were investigated. The BOHB or AcAc was administered at concentrations of 10, 1, or 0.1 mM for 30 min at 4.0 ml/min. High-concentration infusions of BOHB and AcAc (10 mM) produced significant increases in insulin release in the presence of 4.4 mM glucose, but low-concentration infusions of BOHB and AcAc (1 and 0.1 mM) caused no significant changes in insulin secretion from perfused rat pancreas. BOHB (10, 1, and 0.1 mM) and AcAc (10 and 1 mM) infusion significantly inhibited glucagon secretion from perfused rat pancreas. These results suggest that physiological concentrations of ketone bodies have no direct effect on insulin release but have a direct inhibitory effect on glucagon secretion from perfused rat pancreas.