Intraneuronal amyloid precursor protein (APP) and appearance of extracellular β‐amyloid peptide (aβ) in the brain of aging kokanee salmon

Antibodies to human amyloid precursor protein (APP₆₉₅) and beta‐amyloid peptide (Aβ_1‐42) were used to determine timing of amyloidosis in the brain of kokanee salmon (Oncorhynchus nerka kennerlyi) in one of four reproductive stages: immature (IM), maturing (MA), sexually mature (SM), and spawning (SP), representing a range of aging from somatically mature but sexually immature to spawning and somatic senescence. In IM fish, immunoreactive (ir) intracellular APP occurred in 18 of 23 brain regions. During sexual maturation and aging, the number of neurons expressing APP increased in 11 of these APP‐ir regions. Aβ‐ir was absent in IM fish, present in seven regions in MA fish, moderately abundant in 15 regions in SM fish, and was most abundant in all brain regions of SP fish exhibiting Aβ‐ir. Intracellular APP‐ir was observed in brain regions involved in sensory integration, olfaction, vision, stress responses, reproduction, and coordination. Intra‐ and extracellular Aβ_1‐42 immunoreactivity (Aβ‐ir) was present in all APP‐ir regions except the nucleus lateralis tuberis (hypothalamus) and Purkinje cells (cerebellum). APP‐ir and Aβ deposition increase during aging. APP‐ir is present in IM fish; Aβ‐ir usually appears first in MA or SM fish and increases in SM fish as does APP‐ir. Extracellular Aβ deposition dramatically increases between SM and SP stages (1–2 weeks) in all fish, indicating an extremely rapid and synchronized process. Rapid senescence observed in pacific salmon could make them a useful model to investigate timing of amyloidosis and neurodegeneration during brain aging. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 11–20, 2002     

The effect of sodium chlorate and nitrapyrin on the nitrification mediated nitrosation process in soils

Summary The influence of total nitrification to nitrate or partial nitrification to nitrite on the soil organic nitrogen status was examined. NH ₄ ⁺ –¹⁵N was added to the soil in the absence and the presence of NaClO₃, respectively nitrapyrin. The first chemical inhibits only nitrate formation, the second inhibits total nitrification. The accumulation of nitrite nitrogen in the soil at levels up to 5 mg kg^–1 increased the loss of nitrogen. Yet, it did not increase the binding of mineral nitrogen into soil organic matter, relative to the control soil. The data suggest that the biochemistry of the nitrite formation process, rather than the levels of nitrite ions formed, are of primary importance in the role of nitrification mediated nitrosation of soil organic matter.     

Specific localization of 2′,3′-cyclic nucleotide 3′-phosphohydrolase, (Ca2+/Mg2+)-ATPase,and acetylcholinesterase in human erythyrocyte membrane

A procedure was developed for the detection of 2′,3′-cyclic nucleotide 3′-phosphohydrolase in myelin. This assay was sufficiently sensitive to detect the low levels of 2′,3′-cyclic nucleotide 3′-phosphohydrolase in human erythrocytes. The 2′,3′-cyclic nucleotide 3′-phosphohydrolase of human erythrocytes was determined to be exclusively associated with the inner (cytosolic) side of the membrane. Leaky ghostsand resealed ghosts were assayed for 2′,3′-cyclic nucleotide 3′-phosphohydrolase, (Ca²⁺/Mg²⁺-ATPase, and acetylcholinesterase activity, and the 2′,3′-cyclic nucleotide 3′-phosphohydrolase profile is the same as that of the (Ca²⁺/Mg²⁺)-ATPase, an established inner membrane maker.     

Alcohol dehydrogenase isozymes in the mouse: Genetic regulation, allelic variation among inbred strains and sex differences of liver and kidney A2 isozyme activity

Genetic analysis of a proposed cis-acting temporal locus ( Adh-3t ), which regulates alcohol dehydrogenase C₂ (ADH-C₂) acitivity in mouse epididymis extracts, among F₁ (ddN × BALB/c) × ddN male backcross progeny provided evidence for genetic distinctness between the structural ( Adh-3 ) and temporal ( Adh-3t ) loci on chromosome 3. Genetic analysis also confirmed the close, linkage of Adh-1 (encoding liver and kidney ADH-A₂) and Adh-3 (encoding stomach ADH-C₂) to within 0.3 centimorgans on the mouse genome. Evidence is presented for a proposed closely linked cis-acting temporal locus (designated Adh-1t ) for the A₂ isozyme (encoded by Adh-1 ) controlling the activity of this enzyme in mouse kidney extracts, but having no apparent affect on liver and intestine ADH-A₂ activities. An extensive survey of the distribution of Adh-1, Adh-3 and Adh-3t alleles among 65 strains of mice is reported — with the exception of two Japanese strains (ddN and KF), linkage disequilibrium between Adh-3 and Adh-3t was observed. Sex differences in mouse liver and kidney ADH-A₂ activities were observed, with male/female ratios of approximately 0.6 and 3 respectively for these tissue extracts.     

Origin of bombesin-like peptides in human fetal lung

Four different forms of bombesin-like immunoreactive peaks were detected in extracts of human fetal lung by the use of reversed-phase high performance liquid chromatography (HPLC). Peaks I, II, III and IV, (increasing retention time), were eluted using a 14-38% of acetonitrile gradient containing 0.1% trifluoroacetic acid (TFA). Peak II was the major material found in the extract of human fetal lung obtained at 16-20 weeks gestation. None of the four compounds contained in the eluted peaks had the same retention time as amphibian bombesin or porcine gastrin releasing peptide (GRP). On reversed-phase HPLC using two different solvent systems TFA or heptafluorobutyric acid (HFBA) as a hydrophobic counter ion, and in gel filtration chromatography, the chromatographic behavior of the main peak (peak II) was the same as that of the carboxyl terminal fragments of GRP, GRP18-27 or GRP19-27. This suggested that the peptide(s) in peak II resembled in composition the carboxy terminal 9 or 10 amino acids of porcine GRP. Following tryptic digestion the material in peak IV was converted to the more polar compound present in peak II. Two other peptide peaks were eluted close to peak II and these were presumed to be a modification of this main peak. One of the possible biosynthetic steps in the formation of bombesin-like peptides in human fetal lung could be a tryptic conversion of a less polar peptide to a more polar form (peak IV to II).     

Suppression of Plant-parasitic Nematode Populations in Turfgrass by Application of Entomopathogenic Nematodes

We studied the influence of entomopathogenic nematodes , Steinernema carpocapsae and S. riobravis, on natural populations of plant - parasitic nematodes (PPNs) infesting turfgrass in Georgia and South Carolina . S. riobravis applied at 6 109 infective juveniles (IJs) / acre provided up to 95 - 100% control of the root - knot , Meloidogyne sp ., sting , Belonolaimus longicaudatus, and ring nematode , Criconemella sp ., in Georgia , but S. carpocapsae had no effect . S. riobravis was as effective as the chemical nematicide , Fenamiphos (Nemacur 10G) at 4 weeks after treatment and more effective at 8 weeks after treatment . In South Carolina , both S. riobravis and S. carpocapsae applied at 1 109 IJs / acre provided up to 86 - 100 % control of the root - knot , sting and ring nematodes . Application of 6 109 IJs / acre increased control by only 4 - 14 % over the 1 109 dosage . Possible causes of differences in efficacy of S. carpocapsae at the two sites are discussed . It is concluded that S. riobravis may provide effective , predictable and economical control of PPNs in turfgrass .     

Identification of 3-deoxy-lyxo-2-heptulosaric acid in the core region of lipopolysaccharides from Rhizobiaceae

A 3-deoxy-2-heptulosaric acid (DHA), very probably with the lyxo-configuration, was identified in the R-core region of lipopolysaccharides from nodulating strains of Rhizobium leguminosarum, Rhizobium meliloti and from all three biovars of the phytopathogenic Agrobacterium tumefaciens. Its structure could be deduced from the fragmentation pattern of the corresponding alditol acetates obtained after reduction of the 2-keto and the 1.7-carboxy groups by sodium borohydride or sodium borodeuteride. DHA in lipopolysaccharide was not destroyed by periodate and is therefore not in a terminal position. Two DHA-containing oligosaccharides, namely glucosyl (1----4)-3-deoxy-2-heptulosaric acid and rhamnosyl-rhamnosyl-(1----5)-3-deoxy-2-heptulosaric acid could be tentatively identified by mass spectrometric methods amongst the products of mild acidic hydrolysis of lipopolysaccharides of Rhizobium leguminosarum strain 24. The two types of non-nodulating mutants of Rhizobium leguminosarum included in this study did not contain 3-deoxy-2-heptulosaric acid.     

Dormancy in peach (Prunus persica L.) flower buds

Morphological studies were carried out with peach flower buds collected monthly in 1989 and 1990, from two months before leaf fall (7 March) until two to three weeks before bloom (7/8 August). Chilled (2–4°C for 30 days) and unchilled buds were exposed to 20 to 25°C, 100% RH and continuous light. Gibberellin A₃ (3 ng or 30 ng) was applied to some of the non-chilled cuttings at three days intervals. Then, 12, 19, and 26 days after they were planted, the buds were sampled and processed for histological studies. Cultured flower buds (chilled or unchilled) had accelerated anther and gynoecium morphogenesis after 12 days under controlled conditions, compared to buds processed immediately after collection from the field. Chilling treatment augmented the bud culture effect, while Gibberellin A₃ applications to the excised buds retarded bud morphogenesis to a stage comparable to that of buds collected directly from the field. This, suggests that the comparatively high levels of Gibberellin A_1/3 we previously found in mid winter [15, 18] could be at least one of the factors that controls floral bud dormancy by retarding anther and gynoecium development.