Sheep ceruloplasmin: isolation and characterization

Molecular and Cellular Biochemistry - Ceruloplasmin has been isolated from sheep plasma by a procedure involving two chromatographic steps and (NH4)2SO4 fractionation. The ovine protein is similar...     

Cell wall invertases from apex and callus tissues of sugar cane

Calluses were obtained from the stalk apex of sugar cane. Boththe stalk apex and callus tissues possessed firmly bound cellwall invertases. The invertases of each tissue were characterizedon the basis of their Km, optimum pH and the action of variousinhibitors. According to this characterization, the two tissuespossess different isoenzymes. Taking into account the presentisoenzymes and the known cell wall invertases from stalk tissue,we postulated a different pattern of isoenzymes for each organof the sugar cane. These differences suggest that the cell wallinvertases might be used as markers in studies of tissue differentiation. (Received May 27, 1980; )     

Concurrence of theAcarapis species complex (Acari: Tarsonemidae) in a commercial Honey-Bee apiary in the Pacific Northwest

An examination of a commercial honey-bee apiary for theAcarapis species complex revealed the following: queens were essentially free fromAcarapis parasitism colonies were more frequently infested withA. dorsalis andA. woodi thanA. externus; individual worker-bee hosts were rarely parasitized by more than oneAcarapis species. Observed sex ratios, for all three mite species, under the conditions of the relatively low infestation rate observed in this study, favored females over males.     

Identification of small nuclear DNA molecules of the cuban sugarcane cultivar Ja60-5 via pulsed field gel electrophoresis

We present evidence of the existence of at least 7 small nuclear DNA molecules in the Ja60-5 sugarcane cultivar genome. These small molecules were separated by means of transversal alternating field electrophoresis (TAFE); their sizes ranged from about 230–3000 kbp, and they hybridized with telomeric, subcentromeric, and various nuclear DNA probes. Here, we also report the use and the modifications of DNA from microorganisms, to immobilize nuclear DNA from sugarcane suitable for analysis via pulsed field gel electrophoresis. The protocol is simple, inexpensive, and easy to perform.     

Effect of medium composition on the ultrastructure of Lactobacillus strains

The growth of some locally isolated Lactobacillus strains forming D(-) or L(+) lactic acid, Lactobacillus helveticus ATCC 15009 and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 was examined in different media. L. helveticus and Lactobacillus LBL strains formed atypical protoplast-like cells in LAPT medium, sensitive to SDS and proteinase. Specific morphological changes in the cell wall structure of these variants were revealed by transmission and scanning electron microscopy. The effect of glucose and various salts on their appearance was investigated. The prevalent role of metal cations, especially of Mg²⁺, was established.     

The rate limiting step in the reticulocyte uptake of transferin and transferrin iron Effects of some incubation variables

Reticulocytes incubated in an isotonic NaCl saline medium containing glucose, glutamine and amino acids, were able to detach both iron atoms from all the transferrin incorporated by them. In the absence of these metabolites, although transferrin uptake was the same, the reticuloctes failed to remove completely the iron from the transferrin which they incorporated.It has been shown before that there is unspecific as well as specific binding of transferrin to the reticulocyte. By incubating the cells in the presence of a high concentration of bovine serum albumin, we have been able to prevent the unspecific attachment of transferrin.At least 94% of the iodinated transferrin was capable of donating its iron to the reticulocytes.     

Rate of concentration and digestion of radioactive growth hormone preparations injected in rats,as measured by the amount and nature of radioactivity in the tissues

Summary The distribution of radioactivity in the tissues of the rat has been established after the administration of radioactive bovine growth hormone preparations.Bovine growth hormone was used either transformed in to a¹⁴C-guanidinated derivative, which was fully active, of labeled with less than 1 mole per mole of¹²⁵I.The tissue radioactivity distribution curves obtained belong to two different categories: in kidney, liver and spleen there is an early concentration which attains a maximum in 15 minutes after the injection of the hormone, and rapidly declines. In heart, skeletal muscle, pancreas, intestine, bone and fat, the radioactivity increases gradually and a steady-state is reached after 30 to 60 minutes.Kidney is the organ where the highest concentration of radioactivity occurs. However, muscle accumulates more than 60% of the initial doses after 2 hours. Very little radioactivity appears in the urine, in this period.Similar results have been obtained with pharmacological or physiological doses of the labeled hormones.Blood plasma does not degrade the injected hormone but kidney, liver and muscle rapidly produce radioactive fragments soluble in 10% trichloro-acetic acid.Dedicated to ProfessorLuis F. Leloir on the occasion of his 70^th birthday.     

Cell wall invertases from apex and callus tissues of sugar cane

Calluses were obtained from the stalk apex of sugar cane. Boththe stalk apex and callus tissues possessed firmly bound cellwall invertases. The invertases of each tissue were characterizedon the basis of their Km, optimum pH and the action of variousinhibitors. According to this characterization, the two tissuespossess different isoenzymes. Taking into account the presentisoenzymes and the known cell wall invertases from stalk tissue,we postulated a different pattern of isoenzymes for each organof the sugar cane. These differences suggest that the cell wallinvertases might be used as markers in studies of tissue differentiation. (Received May 27, 1980; )     

Effects of prenatal hypoxia on expression of amyloid precursor protein and metallopeptidases in the rat brain

Summary In the present study we have investigated the effect of prenatal hypoxia on expression of amyloid precursor protein (APP) and some metallopeptidases, which regulate β-amyloid peptide (Aβ) levels (neprilysin (NEP) and endothelin-converting enzyme (ECE-1)) in the cortex of rats during different periods of postnatal development. We have found that the level of APP in the sensorimotor cortex (SMC) of rats, analysed by Western blotting, increases from days 1 to 5 of postnatal development and then steadily decreases with age, with the most dramatic decline in the period from day 180 to 600. In the cortex of rats subjected to prenatal hypoxia on day 13.5 of embryogenesis, the postnatal levels of APP were higher than in the control. Secretion of the soluble form of APP (sAPP) by α-secretase was found to be the most active on day 30 of postnatal development and there was a significant decrease in the production of sAPP after prenatal hypoxia. NEP was found to be expressed in the cortex of rats only at the early stages of postnatal development and it was barely detectable in adult rats. The decline of NEP levels during ageing might contribute to accumulation of Aβ in later life in humans. Prenatal hypoxia resulted in a significant decrease of NEP expression on day 10, but its level was recovered when animals were preconditioned to mild hypoxia. A similar phenomenon was observed when the expression of ECE-1 was analysed. Overall, prenatal hypoxia leads to significant changes in the levels of APP and expression of metallopeptidases involved in amyloid metabolism during all postnatal life and preconditioning to hypoxia appeared to be neuroprotective.