Segregation Distortion of Marker Nuclear Genes in Alloplasmic and Isoplasmic Lines of Barley

Inheritance of barley nuclear genes responsible for various morphological marker traits was studied in hybrid populations F₂ and F_a. Nine marker genes showed deviation from Mendelian monogenic inheritance depending on the cross direction and maternal cytoplasm. Segregation biases to both recessive mutant and dominant normal phenotypes were observed. Mechanisms of the segregation bias related to cytoplasm substitution in iso- and alloplasmic lines are discussed.     

Factor 390 chromophores: phosphodiester between AMP or GMP and methanogen factor 420

Two chromophores with absorbance maxima at 390 nm (factors 390) have been isolated from oxidized cells of Methanobacterium thermoautotrophicum delta H. The isolation procedure included anion-exchange chromatography of the soluble cofactor pool followed by reverse-phase chromatography. The factor 390 species are novel derivatives of methanogen coenzyme factor 420 in which the 5-deazaflavin 8-hydroxy group is in a phosphodiester linkage to adenosine 5'-phosphate or guanosine 5'-phosphate. The structural assignments were based, in part, on the UV-visible and 1H NMR spectra. In addition, the results from amino acid analysis, phosphate determination, 31P NMR spectroscopy, and fast atom bombardment mass spectrometry were consistent with the proposed structures. Confirmation of the factor 390 structures was made following phosphodiesterase release of the nucleotide monophosphates from factor 420. The nucleotide monophosphates were identified as AMP and GMP by UV-visible spectra and based on elution position by using reverse-phase and anion-exchange high-performance liquid chromatography. The presence of AMP was further demonstrated by using adenylate-5'-phosphate kinase which induced a spectral shift during conversion of the sample to IMP. In addition, the presence of GMP was established by a specific enzymatic assay.     

A subclass of proteins and sulfated macromolecules secreted by AtT-20 (mouse pituitary tumor) cells is sorted with adrenocorticotropin into dense secretory granules

The AtT-20 cell, a mouse pituitary tumor line that secretes adrenocorticotropin and beta-endorphin, sorts the proteins it externalizes into two exocytotic pathways. Cells that are labeled with [35S]methionine or [35S]sulfate can be shown to transport three acidic polypeptides (65,000, 60,000, and 37,000 mol wt) and at least two sulfated macromolecules into storage secretory granules. When the cells are stimulated by the secretagogue 8-bromo-cAMP, these polypeptides are coordinately secreted with mature adrenocorticotropin into the culture medium. In contrast, a completely different set of secreted polypeptides and sulfated macromolecules does not enter a storage form and is transported to the cell surface more rapidly. Their secretion from the cells is constitutive and does not require the presence of secretagogues. These molecules, like a viral membrane glycoprotein described previously (Gumbiner, B., and R. B. Kelly, 1982, Cell, 28:51-59) are not found in isolated secretory granules and therefore must reach the cell surface in a different exocytotic vesicle. The segregation of a subclass of secretory macromolecules into the secretory granules, despite the existence of another potential secretory pathway, suggests that these molecules have specific functions related to regulated hormone secretion or storage. Presumably all of the proteins secreted by the regulated secretory granule pathway share some common property that targets them to the secretory granule.     

Environmental stress and bacterial infection in channel catfish, Ictalurus punctatus Rafinesque

Channel catfish, Ictalurus punctatus , were injected intraperitoneally with a sublethal dose of Aerornonas hydrophila and then stressed for 144 h by being maintained either in a dissolved oxygen concentration of 1·5 mg/1, 1·2 mg/1 total ammonia, and/or 6·5 mg/1 free CO₂ with a continuous inflow of water. A significant difference in percentage of mortality was noted between treatments ( P < 0·05). The trunk kidneys of surviving stressed fish had significantly higher total bacterial counts than non-stressed controls. A. hydrophila was isolated from 67% of the stressed fish and 9% of the control fish. Edwardsiella tarda , apparently endemic in the population, was isolated from 43% of the stressed fish and 7% of the control fish. Histopathological lesions were in the gills, liver, spleen, trunk kidney, and head kidney of stressed fish, but not control fish.     

Liver microsome phospholipids and cytochrome P.450 conceptration in phenobarbital treated rats fed on different diets

Liver microsomal concentration of cytochrome P.450 is increased in animals which are fed diets rich in polyunsaturated fatty acids. On the other hand, the effects of phenobarbital are more important when the dietary fat is more unsaturated. The unsaturation index in liver microsomal phosphatidylcholines depends on the unsaturation of the dietary fats. The treatment with phenobarbital constantly results in a decrease of the unsaturation index of fatty acids both in lecithins and cephalins. The importance of the liver microsomal cytochrome P.450 increase and the importance of the unsaturation index decrease in liver microsomal lecithins, both promoted by phenobarbital, are in good agreement.     

The biology of pike, Esox lucius L., in a southern eutrophic lake

The biology of pike, Esox lucius L., in a southern productive lowland lake is described. Scales and opercular bones were difficult to read and interpret, and growth estimated had perforce to be based on scale readings. Growth of Slapton pike is average and intermediate between recorded extremes. Both male and female pike reached maximum condition in February, just prior to spawning. The population of pike of over 450 mm fork length in the lake was estimated at 870·6 ± 389·3 in 1975, and 950·4 ± 143.3 in 1976/77. This leads to the conclusion that the pike population has one of the highest biomasses per surface area of water ever recorded. Number of pike per unit area of surface was also high, despite the fact that a significant proportion of the population (fish under 450 mm) could not be adequately sampled. Mean instantaneous mortality rate was 0·53, and mean instantaneous survival rate was 0·59. The roach provided the main item of diet of the pike, with perch taken less readily. Immature pike ate a significant proportion of invertebrates, but roach was again a common feature of the diet of even small fish. Two spawning migrations were identified; at other times of the year, pike were non territorial. The majority of pike spawned in March. Fecundity of a sample of females was assessed. Overall sex ratio was 1:1.     

Pharmacological and Physicochemical Properties of Pre-Versus Postsynaptic 5-Hydroxytryptamine1A Receptor Binding Sites in the Rat Brain: A Quantitative Autoradiographic Study

Numerous data suggested that the pharmacological and biochemical properties of 5-hydroxytryptamine1A (5-HT1A) receptors exhibit some regional differences in the CNS, notably within the raphe nuclei compared with various forebrain areas (such as the hippocampus). This possibility has been further investigated in the dorsal raphe nucleus and two areas within the hippocampus, the dentate gyrus and the CA1 area, using the quantitative autoradiographic technique. The potencies of 5'-guanylylimidodiphosphate to inhibit the specific binding of 125I-Bolton-Hunter-8-methoxy-2-(N-propyl-N-propylamino)tetralin (125I-BH-8-MeO-N-PAT) to 5-HT1A sites and of N-ethylmaleimide to block these sites irreversibly were identical in the dorsal raphe nucleus and the hippocampal areas in rat brain sections. In contrast, slight but significant differences were noted in the pH dependence and pharmacological properties of 5-HT1A sites labeled by 125I-BH-8-MeO-N-PAT in these three regions. Similarly, heat denaturation experiments and tissue exposure to either phospholipase A2 or the alkylating agent 8-methoxy-2-(N-2'-chloropropyl,N-propyl)aminotetraline revealed regional differences in the properties of 5-HT1A sites. However, in most cases, the observed variations were of greater amplitude between the CA1 area and the dentate gyrus, where 5-HT1A sites are located postsynaptically, than between any one of these areas and the dorsal raphe nucleus where they act as (presynaptic) somatodendritic autoreceptors. These data further support that subtypes of 5-HT1A receptors probably exist in the rat brain, but this heterogeneity seems unrelated to the pre- or post-synaptic location of these receptors.     

Effect of tween 80 on exploratory behavior and locomotor activity in rats

Exploratory behavior and locomotor activity is enhanced in male rat pups (aged 10 to 20 days) whose dams received a chronic dose (1.25 ml/l) of Tween 80 via their drinking water. This enhancement manifests itself during the diurnal period of the day. These data suggest that Tween 80 has an effect on the CNS which could lead to misinterpretation of results in toxicology studies that use this compound as a dosage vehicle.