Comparison between (RS)-nipecotic acid and GABA transport in cultured astrocytes: Coupling with two sodium ions

The sodium ion dependency of the uptake of (RS)-nipecotic acid into astrocytes in primary cultures has been studied by performing kinetic analysis at different sodium ion concentrations (16–151 mM).V _max of the saturable component of the astroglial (RS-nipecotic acid uptake is clearly affected by the sodium ion concentration whereasK _m surprisingly remains unaffected. At high (RS)-nipecotic acid concentrations (50 M), uptake rates as a function of the sodium ion concentration were clearly sigmoid. This sigmoid shape was not obvious at lower concentrations of (RS)-nipecotic acid. The calculated Hill coefficients corresponding to all (RS)-nipecotic acid concentrations studied were approximately two. From these results it is concluded that (RS)-nipecotic acid uptake into astrocytes in primary cultures, like astroglical GABA uptake, requires the binding of at least two sodium ions per (RS)-nipecotic acid molecule transported.     

Comparative immunocytochemical localization of putative opioid ligands in the central nervous system

We report a detailed comparative immunocytochemical mapping of enkephalin, CCK and ACTH/beta-endorphin immunoreactive nerves in the central nervous system of rat and guinea pig. Enkephalin immunoreactivity was detected in many groups of nerve cell bodies, fibers and terminals in the limbic system, basal ganglia, hypothalamus, thalamus, brain stem and spinal cord. beta-endorphin and ACTH immunoreactivity was limited to a single group of nerve cell bodies in and around the arcuate nucleus and in fibers and terminals in the midline areas of the hypothalamus, thalamus and mesencephalic periaqueductal gray with lateral extensions to the amygdaloid area. Cholecystokinin immunoreactive nerve fibers and terminals displayed a distribution similar to that of enkephalin in many regions; but striking differences were also found. An immunocytochemical doublestaining technique, which allowed simultaneous detection of two different peptides in the same tissue section, showed that enkephalin-, CCK- and ACTH/beta-endorphin-immunoreactive nerves although closely intermingled in many brain areas, occurred separately. The distributions of nerve terminals containing these neuropeptides showed striking overlaps and also paralleled the distribution of opiate receptors. This may suggest that enkephalin, CCK, ACTH and beta-endorphin may interact with each other and with opiate receptors.     

Reciprocal Embryo Transfer Between Repeat Breeder and Virgin Heifers — an Experimental Model

The aim of the study was to evaluate the importance of mother-concaptus relationships for the elevated embryonic loss in repeat breeder heifers. Embryos were collected by non-surgical technique, classified and transferred surgically or non-surgically to synchronized, inseminated recipients. The embryos were transferred to the uterinehorn contralateral to the corpus luteum. The embryos were transferred from repeat breeder heifers (RBH) to virgin heifers (VH) or from VH to RBH. After slaughter 4 weeks after transfer there was no difference in emhryonic survival between heifer categories following transfer or insemination. In some animals degenerated foetal membranes were found in the nonpregnant horn. The study indicates embryonic morphology rather than the category of donor or recipient as influencing the embryonic survival rate.     

Cartilage matrix proteins. A basic 36-kDa protein with a restricted distribution to cartilage and bone

A non-collagenous quantitatively prominent protein was purified from guanidine hydrochloride extracts of bovine tracheal cartilage. Purification was achieved by cesium chloride density gradient centrifugation and chromatography on DEAE-cellulose at pH 7.0 followed by CM-cellulose at pH 5.0. The protein has a marked tendency to form aggregates in denaturing solutions of high ionic strength, e.g. 6 M guanidine hydrochloride. The purified protein contains a single, Mr 36,000 polypeptide chain, with a particularly high content of leucine. It contains about 1% carbohydrate with a remarkable absence of hexosamines and sialic acid, whereas xylose, galactose, mannose, and fucose were identified in the preparation. The protein was identified in extracts of cartilage and bone and could be shown to be primarily extracellular. Tendon may contain trace amounts of the protein, whereas extracts of several other tissues showed no immunoreactivity in enzyme-linked immunosorbent assay.     

Intraspecific variability in response to stimuli for male and ephippia formation in Daphnia pulex

Natural clones and clones from laboratory crossings of Daphnia pulex have been tested in their response to stimuli for male and ephippia formation. The clones are from ponds in Illinois, USA, an area with both obligate and cyclical clones of D. pulex. The progeny from two types of crosses were studied: 1) crosses between an obligate clone producing males and a cyclical clone producing only females, and 2) self-fertilization within a cyclical clone producing both sexes. Both the natural and the artificial clones showed great variation in response to environmental stimuli for males. Ephippia response seems more equal among the clones, but two of the artificial clones could hardly be stimulated to produce ephippia in the induction experiments. In crowded cultures, however, they produced a few. Crossings between cyclicals and obligates yielded mostly cyclical progeny. Progeny from the selfed clone had low survival and fecundity.     

Secondary fatty alcohols of Mycobacterium xenopi.

Secondary alcohols of Mycobacterium xenopi were studied by gas chromatography and gas chromatography-mass spectrometry. Mycobacterial cells were hydrolysed and the liberated alcohols separated by extraction and analysed both underivatized and as trimethylsilyl, methyl ether- and pentafluorobenzoyl derivatives. Seven straight-chain secondary alcohols containing from 18 to 24 carbon atoms and two branched-chain secondary alcohols with 21 and 23 carbon atoms were present in all of the studied strains.     

Detection of microbial contamination in fermentation processes: mass spectrometric determination of gram-negative bacteria in Leuconostoc mesenteroides cultures

Gas chromatography/mass spectrometry was used to detect the presence of Enterobacter cloacae in cultures of Leuconostoc mesenteroides, an organism used in an industrial process for production of dextrane. The penta-fluorobenzoyl-methyl ester derivative of 3-hydroxy-myristic acid, a characteristic compound of gram-negative bacteria, was used as the analyte. By using gas chromatography/mass spectrometry with selected ion monitoring, E. cloacae was determined over the range of 1 ppm to 1% in cultures of L. mesenteroides. The proposed analytical approach represents a useful alternative to conventional methods for determining contaminating organisms in industrial fermentation processes.