220 results for Journal article, 1980

  • A correlation between protein thermostability and resistance to proteolysis.

    Daniel, Roy M.; Cowan, Don A.; Morgan, Hugh W.; Curran, M.P. (1982)

    Journal article
    University of Waikato

    The loss of activity due to proteolysis of purified L-asparaginase and beta-galactosidase from different sources correlates with the thermal instability of the enzymes. A similar correlation is found when populations of soluble proteins from micro-organisms grown at different temperatures are compared for proteolytic susceptibility and thermal stability. It is proposed that there is a general correlation between the thermostability of proteins and their resistance to proteolysis.

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  • Thermus filiformis sp. nov., a Filamentous Caldoactive Bacterium

    Hudson, J. Andrew; Morgan, Hugh W.; Daniel, Roy M. (1987)

    Journal article
    University of Waikato

    In a preliminary investigation the isolation of a caldoactive filamentous microorganism from a New Zealand hot spring was reported. This organism is described here as a new species belonging to the genus Thermus, namely, Thermus filiformis, based on ultrastructural, phenotypic, and anomalous Gram type characteristics. The cell wall of T. filiformis resembles that of Thermus aquaticus apart from the presence of an extra layer. The Thermus species tested, including T. filiformis, are negative for the aminopeptidase test, which is unusual for a gram-negative genus. T. filiformis is nonproteolytic, unlike most other Thermus strains, and also differs radically from other strains in morphology when it is observed by using phase-contrast microscopy. The single strain of the species has been deposited with the American Type Culture Collection as strain ATCC 43280T (T = type strain).

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  • Interactions of calcium and other metal ions with caldolysin, the thermostable proteinase from Thermus aquaticus strain T351.

    Khoo, T.C.; Cowan, Don A.; Daniel, Roy M.; Morgan, Hugh W. (1984)

    Journal article
    University of Waikato

    Caldolysin, the extracellular proteinase from the extreme thermophile Thermus aquaticus strain T351, is stabilized by Ca2+. A variety of metal ions were able to substitute for Ca2+. Most were unable to confer as much stability as Ca2+, with the exception of the lanthanide ions, which increased the half-life at 95 degrees C from 1 h to more than 4 h. Results from a variety of separation methods indicated that caldolysin binds 6 Ca2+ ions/molecule of enzyme. The presence of non-linear Ca2+ titration plots, and the removal of 4 Ca2+ ions/molecule by treatment with a cationic ion-exchange gel suggested that caldolysin possesses at least two different types of Ca2+-binding sites, with different affinities. Average binding constants of the two types of binding sites were 2.8 X 10(4)M-1 (for the low-affinity sites) and 7.5 X 10(5) M-1 (for the high-affinity sites). The total Ca2+-binding free energy for caldolysin was shown to be greater than for either thermolysin or Bacillus subtilis neutral proteinase. It appears that the higher thermostability of caldolysin is due to the presence of 6 Ca2+ ions rather than 4 Ca2+ ions/molecule.

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  • Anaerobic growth, nitrate reduction and denitrification in 46 rhizobium strains

    Daniel, Roy M.; Limmer, A.W.; Steele, K.W.; Smith, I.M. (1982)

    Journal article
    University of Waikato

    A total of 46 rhizobial strains were assessed for anaerobic growth in the presence of nitrate, and, using the criteria of nitrate utilization and nitrous oxide and nitrogen production, for their ability to denitrify. Nitrite production was also measured. Half of the strains were denitrifiers: these included all five strains of R. meliloti tested which produced N2 from nitrate and most of the slow-growing rhizobia, but none of the 14 strains of R. trifolii.

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  • Enumeration of thermophilic heterotrophs in Geothermally heated Soils from Mount Erebus, Ross Island, Antarctica

    Hudson, J. Andrew; Daniel, Roy M. (1988)

    Journal article
    University of Waikato

    Soil samples with temperatures up to 64°C were collected from Mount Erebus, an active volcano located on Ross Island, Antarctica. Acridine orange direct counts and most probable number counts of soil samples stored at 4°C for 2 months showed a wide variation in the number of thermophilic microorganisms in different soils. Organisms similar to Clostridium thermohydrosulfuricum, Bacillus schlegelii, and Bacillus acidocaldarius, as well as neutrophilic Bacillus strains, were isolated.

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  • Cellulases from extremely thermophilic bacteria

    Sharrock, Keith R.; Sissons, Christopher H.; Daniel, Roy M.; Morgan, Hugh W. (1983)

    Journal article
    University of Waikato

    Cellulose is the most abundant biopolymer on earth, and is the major component of urban waste. Thus cellulose must be seen as a very significant renewable source of chemical foodstocks when fossil fuels become restricted.

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  • A provisional survey of the interaction between net photosynthetic rate, respiratory rate, and thallus water content in some New Zealand cryptogams

    Snelgar, W.P.; Brown, D.H.; Green, T.G. Allan (1980)

    Journal article
    University of Waikato

    The effect of water content on photosynthetic and respiratory rates in eight lichen species and one bryophyte species were studied using an injection infrared gas analyser technique. All species snowed a strong relationship between net assimilation rate (NAR), respiration rate, and water content similar to relationships reported in published studies overseas. Species from moist habitats showed negative NAR at low water contents. Species from high-light areas showed a depression in NAR at high water contents which could be alleviated by higher light intensities. The experiments confirmed the suitability of New Zealand species for these studies.

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  • Bottom sediments of Lake Rotoma

    Nelson, Campbell S. (1983)

    Journal article
    University of Waikato

    Lake Rotoma is a deep (70-80 m), oligotrophic, warm monomictic lake of volcanic origin with insignificant stream inflow and no clearly defined outflow. For at least 60 years up to 1972 the lake level fluctuated markedly about an overall rising trend of some 6-10 m. Nearshore profiles are related to the prevailing wave climate superimposed upon the overall rising lake level, shelves being wider, less steep, and deeper about the more exposed eastern and southern shorelines. The outer portions of shelves extending well below modern storm wave base into waters as deep as 15-25 m are relict features from lower lake level stands. Sediments fine from sand-gravel mixtures nearshore to silts in basinal areas. Their composition reflects a composite provenance involving the lavas and tephras about the lake, as well as intralake diatom frustules and organic matter. The distribution pattern of surficial bottom sediments is an interplay between grains of both biological and terrigenous origin, supplied presently and in the past by a variety of processes, that have been dispersed either by the modern hydrodynamic regime or by former ones associated with lower lake levels. These interrelationships are structured by erecting 5 process-age sediment classes in the lake, namely neoteric, amphoteric, proteric, palimpsest, and relict sediments, analogous to categories postulated for sediments on oceanic continental shelves. Short-core stratigraphy includes the Kaharoa (A.D. -1020) and Tarawera (A.D. 1886) tephras. The rates of sedimentation of diatomaceous silts in basinal areas have more than doubled since the Tarawera eruption, indicating an overall increase in the fertility level of lake waters associated, perhaps, with recent farm development in the catchment.

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  • Pyroclastic deposits and volcanic history of Mayor Island

    Buck, M.D.; Briggs, Roger M.; Nelson, Campbell S. (1981)

    Journal article
    University of Waikato

    The emergent summit of Mayor Island, Bay of Plenty, New Zealand, is a peralkaline rhyolite volcano constructed by: a sequence of lava flows, the Tutaretare Rhyolite Formation new; and pyroclastic deposits, the Oira Pyroclastite Formition (new). These 2 formations constitute the Mayor Island Group new. The pyroclastic deposits mantle most of the outer slopes of the island, in places exceeding 100 m in thickness, and also occur interbedded with lava flows of the main cone. The pyroclastics have been informally assigned on the basis of their compositional, welding and textural, and sedimentary structural characteristics to one or other of 15 lithotypes which may be related to particular modes of eruption and emplacement, of both airfall (phreatic, phreatomagmatic, phreatoplinian, and plinian types) and pyroclastic flow (ignimbrite, nuée ardente, and base surge types origins). A sixteenth lithotype comprises epiclastic deposits formed possibly by catastrophic overspill from an ancestral crater lake. Two new radiocarbon dates on logs from the pyroclastic deposits are recorded: (Wk105) 8000 ± 70 years B.P., and (Wk77) 6340 ± 190 years B.P. Recognition of the calcalkaline Rotoehu and possibly Rotoma Ashes on Mayor Island, together with the new radiocarbon dates, enables definition of 8 phases of major volcanic activity, each separated by relatively quiescent periods with erosion and paleosol formation. Volcanism commenced sometime prior to 42 000 years ago and has continued intermittently up to the eruption of the young dome lavas, possibly less than 1000 years ago. At present, only I Mayor Island-derived tephra has been identified on the mainland of the North Island, namely the Tuhua Tephra dated (Wk77) at source as 6340 ± 190 years B .P. However, the character and magnitude of several of the pyroclastic units on Mayor Island is such that recognition of other peralkaline tephras is anticipated in northern North Island.

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  • Denitrification by rhizobia: A possible factor contributing to nitrogen losses from soils

    Daniel, Roy M.; Steele, K.W.; Limmer, A.W. (1980)

    Journal article
    University of Waikato

    The intensive pastoral farming system on which New Zealand animal production is based is almost completely dependent upon the rhizobium-legurne symbiosis for the fixed nitrogen required for pasture production. The average annual fixation has been measured as 184 kg nitrogen/ha in developed lowland pastures Hoglund et cii., 1979 and about 13 kg nitrogen/ha in poorly developed bill country pastures (Grant and Lambert, 1979). From these figures it can be estimated that rhizobia in New Zealand pastures fix in excess of one million tonnes of nitrogen an nually. The current annual application of fertilizer nitrogen to pastures is about 12 500 tonnes (O'Connor, 1979).

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  • Distribution of reverse gyrase in representative species of eubacteria and archaebacteria

    Collin, R.G.; Morgan, Hugh W.; Musgrave, D.R.; Daniel, Roy M. (1988)

    Journal article
    University of Waikato

    Reverse gyrase is a topoisomerase which positively supercoils closed circular plasmid DNA. Reverse gyrase activity is restricted to the thermoacidophilic group of archaebacteria. Thermophilic methanogens and eubacteria and all mesophilic organisms screened had no reverse gyrase activity. The result supports the deep phylogenetic divergence in archaebacterial evolution.

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  • Proteases from extreme thermophiles

    Coolbear, Tim; Daniel, Roy M.; Cowan, Don A.; Morgan, Hugh W. (1988)

    Journal article
    University of Waikato

    Extremely thermophilic bacteria are those that grow optimally at 65 ℃ or higher. Comparative data are presented on extracellular proteases from two extremely thermophilic eubacteria and one extremely thermophilic archaebacterium. The eubacteria were a Bacillus isolate (protease unnamed) and a Thermus isolate (protease named caldolysin) with optimum growth temperatures of 65 ℃ and 75 ℃, respectively. The archaebacterium was a Desulfurococcus isolate (protease named archaelysin) with an optimum growth temperature of 88 ℃.

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  • A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1.

    Plant, Adrian R.; Parratt, S.; Daniel, Roy M.; Morgan, Hugh W. (1988)

    Journal article
    University of Waikato

    Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.

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  • A simple and efficient method for preparing and dispensing anaerobic media

    Patel, B.K.C.; Morgan, Hugh W.; Daniel, Roy M. (1985)

    Journal article
    University of Waikato

    An Oxford pipettor (model S-A) was used for simultaneously preparing and dispensing anaerobic media. Media prepared by this method have been successfully used for cultivation of extremely thermophilic bacteria.

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  • A numerical classification of some Thermus isolates

    Hudson, J. Andrew; Daniel, Roy M.; Morgan, Hugh W. (1986)

    Journal article
    University of Waikato

    A numerical classification was performed on a collection of 45 Thermus isolates recovered from New Zealand hot pools and on six type strains including T. aquaticus and "T. thermophilus". Unweighted average linking (UPGMA) and single linkage clustering methods were applied to similarity matrices derived from simple matching (SSM) and Jaccard similarity (SJ) coefficients. Differences were observed between phenograms derived from SSM and SJ coefficients, indicating that some of the clusters formed were derived from a significant component of negative matches. Test error was estimated at 2.9%. In the UPGMA/SSM phenogram, seven clusters were formed. A majority of the New Zealand isolates did not cluster with non-New Zealand isolates. Analysis of variance showed that there was a relationship between the composition of the clusters and the temperature and pH of the source of the isolate. Chi-squared testing showed that, within New Zealand, the geographical source of the isolate had no bearing on the clusters formed.

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  • Isolation of an extremely thermophilic chemoorganotrophic anaerobe similar to Dictyoglomus thermophilum from New Zealand hot springs

    Patel, B.K.C.; Morgan, Hugh W.; Wiegel, J.; Daniel, Roy M. (1987)

    Journal article
    University of Waikato

    A strain similar to Dictyoglomus thermophilum, isolated from a New Zealand hot spring, is described. This strictly anaerobic, Gram-negative, non-motile and nonsporulating bacterium usually exists as long thin filaments of 5 to 25 µm by 0.35 to 0.45 µm. Rotund bodies are commonly observed. Thin sections of the cells revealed a two-layered cell wall. The optimum temperature and pH for growth was 70°C and 7.0 and 7.5 respectively. No growth was observed at 40°C and 85°C or at pH 4.5 to pH 9.0. The organism fermented glucose, maltose, mannose, xylose, lactose, cellobiose, galactose and sucrose and produced acetate as the major end-product with significant amounts of lactate, H2 and CO2 and only traces of ethanol. The doubling time on glucose was 10 h. The DNA base composition was 29.5% guanine plus cytosine as determined by the thermal denaturation method. Growth was inhibited by penicillin, tetracycline and chloramphenicol indicating that the organism was a eubacterium. These features are in common with the newly described species Dictyoglomus thermophilum to which the New Zealand isolate belongs.

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  • Temperate skeletal carbonate sediments on Scott shelf, northwestren Vancouver Island, Canada

    Nelson, Campbell S.; Bornhold, Brian D. (1983)

    Journal article
    University of Waikato

    Scott shelf ( 2000 km2), centred at Scott Islands, northwestern Vancouver Island, is mainly shallower than 150 m, topographically diversified, and floored by bedrock outcrops and terrigenous lithic gravels and sands left stranded following the post-glacial rise in sea level (13,000 yrs B.P.). It lies in a zone of vigorous wind-wave currents and strong tidal flows, but is largely starved of modern terrigenous sediment. As a consequence it is slowly accumulating a thin, discontinuous blanket of clean, skeletal carbonate sands and gravels, admixed to varying degrees with the underlying terrigenous deposits. Principal skeletal contributors are infaunal bivalves (on coarse sandy and gravelly substrates), barnacles (on low-amplitude gravelly ridges), bryozoans (on bedrock outcrops and boulders) and benthic foraminifera (on fine sands in deep (> 100 m) waters south of the Scott Islands). Living carbonate benthos are scattered and generally sparse, occupying specific ecologic niches, and the shelf-wide rate of carbonate production is low. Skeletons are fragmented, transported and mixed during storms and are concentrated within bedrock hollows and crevices, and shallow depressions between gravel ridges. Where infaunal bivalves are abundant the carbonates are dominated by aragonite, but otherwise the skeletal hashes are predominantly calcitic. Many grains, and especially aragonitic ones, are corroded and weakened by epilithic and endolithic bioerosion, and probably also by marine and dissolution. The most corroded shells have ages of only about 1000 yrs so that their preservation potential is low. The character of Scott shelf skeletal carbonate deposits reflects their temperate latitude, cold-water heritage.

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  • Cluster Chemistry : XVII.Radical ion-initiated synthesis of ruthenium cluster carbonyls containing tertiary phosphines, phosphites, arsines, SbPh₃, or isocyanides

    Bruce, Michael I.; Matisons, Janis G.; Nicholson, Brian K. (1983)

    Journal article
    University of Waikato

    The syntheses of over sixty known and new derivatives of Ru₃(CO)₁₂ and H₄Ru₄(CO)₁₂ by substitution reactions initiated by sodium diphenylketyl are described. The range of ligands studied includes isocyanides, tertiary phosphines and phosphites, tertiary arsines and SbPh₃. The reactions are characterised by high degrees of specificity and conversion: under mild conditions up to four ligands can be introduced. Comparisons with the corresponding thermally induced reactions are made in several cases. The reactions provide routes to mixed ligand derivatives of the cluster carbonyls, although account of relative Lewis base strengths of the ligands may have to be taken. Possible mechanisms of these reactions are discussed briefly, as are the IR ν (CO) spectra of the Ru₃ (CO)12-nLn complexes.

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  • Anionic germanium polycobalt carbonyl clusters. Part 3. Preparation and structures of [Net₄][Ge₂Co₇(CO)₂₁] and [Net₄][Ge{Co₇(CO)₂₀}]; two large clusters incorporating tetrahedral GeCo₃ units

    Duffy, D. Neil; Mackay, Kenneth M.; Nicholson, Brian K.; Thomson, Ralph A. (1982)

    Journal article
    University of Waikato

    Reactions of the [Ge{Co₅(CO)₁₆}]⁻ cluster have given rise to two new germanium–polycobalt cluster anions, characterised as their Net₄⁺ salts by X-ray crystallography. The complex [NEt₄][Ge₂Co₇(CO)₂₁](1a) forms triclinic crystals, space group P , with a= 13.085(2), b= 19.712(7). c= 12.220(8)Å, α= 109.10(3), β= 92.60(2), γ= 129.32(3)°, and Z= 2. The structure was solved by direct methods and refined to R=R′= 0.046 for 2 076 reflections with l > 3σ(l). The anion (1) consists of two –GeCo₃(CO)₉ units bonded mutually trans about a trigonal planar Co(CO)₃ group, giving idealised C3v, symmetry. For [Net₄][Ge{Co₇(CO)₂₀}](2a). crystals are monoclinic, space group P21/c, with a= l2.761(7), b= 18.415(3), c= 17.675(4)Å, β= 102.91(3)°, and Z= 4. The structure was refined to R= 0.077, R′= 0.074, for 1 123 reflections with I > 2σ(I). The anion (2) is a derivative of the C3v structure of [Co₄(CO)₁₂] with the axial carbonyl ligand of one basal cobalt replaced by a –GeCo₃-(CO)₉⁻ fragment. The Co4 tetrahedron is disordered.

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  • Anionic germanium polycobalt carbonyl clusters. Part 2. Preparation and structure of [Net₄][Ge{Co₅(CO)₁₆}], a cluster which contains five-co-ordinate germanium

    Croft, Rex A.; Duffy, D. Neil; Nicholson, Brian K. (1982)

    Journal article
    University of Waikato

    Addition of [Co(CO)₄]⁻ to [Ge{Co₄(CO)n}](n= 16, 14, or 13) under mild conditions gives good yields of [Ge{Co₅(CO)₁₆}]⁻. This forms crystals with Net₄⁺ which are orthorhombic, space group Pn2₁ a with a= 12.014(1), b= 36.938(4), c= 15.249(2), and Z= 8. The crystal structure was solved by direct methods and refined, with some difficulty due to pseudo-symmetry, to R= 0.088, R′= 0.081, for 1 590 unique reflections with F² > 2σ(F²). The anion has a GeCo₅ metal skeleton consisting of a GeCo₂ triangle and a GeCo₃ tetrahedron sharing a common apex at Ge. The five Ge–Co bond lengths vary from 2.33 to 2.51 Å. Three of the CO ligands on the GeCo₃ unit bridge the three Co–Co bonds, with two terminal CO groups on each Co atom. On the GeCo₂ moiety there are six terminal and one bridging carbonyls.

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