Nitrogen and phosphorus content of flow from drains fertilized with cow manure slurry

Summary The rate of flow and nitrate and phosphorus content of the water from four drained sandy and clayey plots of size 12×60 m cropped to continuous corn were determined following two annual applications of different rates (0, 260, 390 and 520 kg N/ha) of cow manure slurry. The drain flow was directly related to the rainfall and was greatly influenced by soil texture. The N losses were greater in 1972 (7.8 to 19.1 kg N/ha) than in 1971 (0.4 to 7.8 kg N/ha) because of more summer rainfall. Nitrogen and phosphorus losses were larger from the sandy plots than from the clayey plots. The manure application rates had no apparent effect on nitrogen losses in the drain water.     

Iron and Porphyrin Trafficking in Heme Biogenesis

Iron is an essential element for diverse biological functions. In mammals, the majority of iron is enclosed within a single prosthetic group: heme. In metazoans, heme is synthesized via a highly conserved and coordinated pathway within the mitochondria. However, iron is acquired from the environment and subsequently assimilated into various cellular pathways, including heme synthesis. Both iron and heme are toxic but essential cofactors. How is iron transported from the extracellular milieu to the mitochondria? How are heme and heme intermediates coordinated with iron transport? Although recent studies have answered some questions, several pieces of this intriguing puzzle remain unsolved.     

Microtubule-associated protein tau. A component of Alzheimer paired helical filaments

Microtubule-associated protein tau was purified from bovine brain microtubules by either (1) phosphocellulose chromatography, (2) heat treatment at pH 6.4, (3) heat treatment at pH 2.7, (4) heat treatment at pH 2.7 followed by extraction with perchloric acid and precipitation with glycerol, or (5) by precipitation with ammonium sulfate followed by extraction with perchloric acid. All of these tau preparations reacted specifically with antibodies to Alzheimer paired helical filaments. Affinity purified antibodies to tau labeled both Alzheimer neurofibrillary tangles and plaque neurites but not amyloid in Alzheimer brain tissue sections and labeled paired helical filament polypeptides on Western blots. Human brain tau and paired helical filament polypeptides co-migrated on sodium dodecyl sulfate-polyacrylamide gels. These results suggest that tau is a major component of Alzheimer paired helical filaments.     

Polyester Wadding for Specimen Orientation During Embedding in Methacrylates

Polyester fibers are not dissolved by either glycol methacrylate or methyl methacrylate. Commercial polyester wadding is consequently an advantageous material to use in getting precise orientation of tissue specimens during embedding in methacrylate.     

Crystal structure of Boc-Ala-Aib-Ala-Aib-Aib-methyl ester,a pentapeptide fragment of the channel-forming ionophore suzukacillin

t-Buthyoxycarbonyl-L -alanyl-α-aminiosobutyryl-L -alanyl-α-aminoisobutyryl-α-aminoisobutyric acid methyl ester (t-Boc-L -Ala-Aib-L -Ala-Aib-Aib-OMe), C₂₄H₄₃N₅O₈, an end-protected pentapeptide with a sequence corresponding to the 6th through the 10th residues in suzukacillin, crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 11.671, b = 14.534, c = 17.906 Å and z = 4. The molecule exists as a right-handed 3₁₀-helix with a pitch of 6.026 Å. The helix is stabilized by three 4 → 1 hydrogen bonds with the NH groups of Ala(3), Aib(4), and Aib(5) hydrogen bonding to the carbonyl oxygens of t-Boc, Ala(1), and Aib(2), respectively. The helical molecules arrange themselves in a head-to-tail fashion along the a direction in such a way that the NH groups of Ala(1) and Aib(2) hydrogen bond to the carbonyl oxygens of Aib(4) and Aib(5), respectively, of a translationally related molecule. The helical columns thus formed close-pack nearly hexagonally to form the crystal.     

Effect of acute gamma irradiation on initiation and maturation of vascular tissues in stems of capsicum annuum L.

The effect of acute gamma rays (⁶⁰Co; 1 to 10 kR) on the vascular differentiation in stems of seedlings of Capsicum annuum L. long fruited cultivar at 8-loaf stage of development. Prooambium, phloem and xylem of irradiated seedlings showed an early initiation and maturation in terms of distance from the tip. Magnitude of these differences increased with the increasing exposures and time following irradiation. In irradiated seedlings there is a ohange in the developmental sequence of metaphloem and metaxylem when they first appear (in terms of number of leaf primordia). There is also a general increase in the number of procambial cells, sieve elements and vessel elements after irradiation. The early initiation and maturation of the vascular tissue is correlated with the growth inhibition resulting from cell death and suppression of cell division activity in the shoot apex.     

Screening Actinomycetes for Extracellular Peroxidase Activity

A diverse collection of actinomycete strains were screened for production of extracellular peroxidase activity by adapting a chemiluminescence analysis system developed for horseradish peroxidase-based enzyme-linked immunosorbent assay. Extracellular peroxidase activity was found to be common but quantitatively variable, and this rapid and sensitive screening system permitted identification of a small group of high-producing strains. A range of spectrophotometric assays were compared for the measurement of peroxidase activity in concentrated culture supernatants of two selected thermophilic streptomycetes. Of these, the peroxide-dependent oxidation of 2,4-dichlorophenol was identified as the most robust and reproducible assay for quantitative studies.     

Petiolar felt-sheath of palm: A new matrix for fungal immobilization

Summary Petiolar felt-sheath of palm (Livistona chinensis) has been successfully used as a new biostructural matrix for the immobilization of fungal hyphae. The reticulated felt-sheath is made up of fibrous bundles having irregularly scattered membranous-foliose and fibrous outgrowths woven into a cohesive multi-layered mesh. Immobilization of Aspergillus niger was achieved with both spore and hyphal suspensions as the inoculum. Growth in immobilized cultures was 19% greater than in free cultures.     

Regulation of calmodulin content in synaptic plasma membranes by glucocorticoids

Synaptic plasma membranes (SPM) from the brain are known to have specific binding sites for several steroid hormones, but the mechanisms of membrane transduction of steroid signals is not understood. In this study, corticosterone was found to prevent temperature-dependent dissociation of endogenous calmodlin (CaM) from highly purified SPM from rat cerebral cortex. The steroid stabilizes Ca²⁺-dependent membrane binding of endogenous CaM (78% of total CaM), whereas Ca²⁺-independent binding of CaM (the other 22%) is not affected. The stabilization of membrane binding of endogenous CaM by corticosterone is concentration-dependent, with the maximal effect occurring at steroid concentration of 1 M. The EC₅₀ is estimated as 130 nM, which is almost identical to the K_d of specific binding of the steroid to SPM (120 nM) reported previously. The effect in stabilizing membrane binding of CaM is specific to corticosterone and other glucocorticoids (cortisol, dexamethasone and triamcinolone); gonadal steroids (17-estradiol, progesterone and testosterone) are ineffective. Furthermore, corticosterone administration in vivo (2 mg/kg, i.p.) produced a rapid increase of CaM content in SPM, occurring within 5 min after steroid injection and persisting for at least 20 min. Since CaM mediates a variety of biochemical processes in synaptic membranes, we hypothesize that the effect of glucocorticoids in promoting membrane binding of CaM may lead to a cascade of consequences in synaptic membrane function.Special issue dedicated to Dr. Sidney Ochs.