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Showing papers by "University of Hohenheim published in 1994"


Journal ArticleDOI
TL;DR: Basic research, including the quantification of nutrient uptake and transport by fungal hyphae in soil and regulation at the fungal-plant interface, is essential to support the selection and utilization of mycorrhizal fungi on a commercial scale.
Abstract: The role of mycorrhizal fungi in acquisition of mineral nutrients by host plants is examined for three groups of mycorrhizas. These are; the ectomycorrhizas (ECM), the ericoid mycorrhizas (EM), and the vesicular-arbuscular mycorrhizas (VAM). Mycorrhizal infection may affect the mineral nutrition of the host plant directly by enhancing plant growth through nutrient acquisition by the fungus, or indirectly by modifying transpiration rates and the composition of rhizosphere microflora.

1,327 citations


Book ChapterDOI
TL;DR: Understanding is poor concerning the processes taking place in the apoplasm of root rhizodermal cells and of the role of low-molecular-weight root exudates and siderophores in Fe acquisition of plants growing in soils of differing Fe availability.
Abstract: Two different types of root response to Fe deficiency (strategies) have been identified in species of the Plant Kingdom. In Strategy I which occurs in all plant species except grasses, a plasma membrane-bound reductase is induced with enhanced net excretion of protons. Often the release of reductants/chelators is also higher. In Strategy II which is confined to grasses, there is an increase in the biosynthesis and secretion of phytosiderophores which form chelates with FeIII. Uptake of FeIII phytosiderophores is mediated by a specific transporter in the plasma membrane of root cells of grasses. From results based mainly on long-term studies under non-axenic conditions this classification into two strategies has been questioned, and the utilization of Fe from microbial siderophores has been considered as an alternative strategy particularly in grasses. Possible reasons for controversial results are discussed in some detail. The numerous effects of microorganisms in non-axenic cultures, and the as yet inadequate characterization of the so-called standard (basic) reductase present major limitations to understanding different mechanisms of Fe acquisition. In comparison with the progress made in identifying the cellular mechanisms of root responses in Strategy I and Strategy II plants, our understanding is poor concerning the processes taking place in the apoplasm of root rhizodermal cells and of the role of low-molecular-weight root exudates and siderophores in Fe acquisition of plants growing in soils of differing Fe availability.

512 citations


Journal ArticleDOI
TL;DR: This review is a survey of bacterial dehalogenases that catalyze the cleavage of halogen substituents from haloaromatics, haloalkanes, h Haloalcohols, and h Haloalkanoic acids.

422 citations


Journal ArticleDOI
TL;DR: In primary (source) leaves, but not in trifoliate leaves, concentrations of reducing sugars, sucrose and starch were also differently affected by low nutrient supply.
Abstract: The influence of varied supply of phosphorus (10 and 250 mmol P m -3 ), potassium (50 and 2010 mmol K m -3 ) and magnesium (20 and 1000 mmol Mg m -3 ) on the partitioning of dry matter and carbohydrates (reducing sugars, sucrose and starch) between shoots and roots was studied in bean (Phaseolus vulgaris) plants grown in nutrient solution over a 12 d period. Shoot and root growth were quite differently affected by low supply of P, K, and Mg. The shoot/root dry weight ratios were 4.9 in the control (sufficient plants), 1.8 in P-deficient, 6.9 in K-deficient and 10.2 in Mg-deficient plants. In primary (source) leaves, but not in trifoliate leaves, concentrations of reducing sugars, sucrose and starch were also differently affected by low nutrient supply

417 citations


Journal ArticleDOI
TL;DR: A stimulatory effect of organic P in the form ofphytate on mycorrhizal infection and hyphal growth as well as the efficient use of phytate-P by phosphatase of mycor Rhizosphere and hyphae are demonstrated.
Abstract: To examine the phosphatase activity of vesicular-arbuscular (VA) mycorrhizal fungi in the rhizosphere and hyphosphere, mycorrhizal and non-mycorrhizal wheat (Triticum aestivum L.) were grown for 60 days in two sterilized soils in pots with five compartments, a central one for root growth (rhizosphere) and two adjacent on both sides next to the root compartment for hyphal growth (hyphosphere) and an outer compartment on both sides where root and hyphae could not penetrate. Compartmentation was accomplished by a 30 μm nylon net or a 0.45 μm membrane, in the two types of compartment, respectively. All compartments received a uniform concentration of phosphorus (200 P mg kg−1 soil), either in organic (Na-phytate) or inorganic [Ca(H2PO4)2] form. Plants were inoculated with Glomus mosseae (Nicol & Gerd) Gerd & Trappe or remained uninfected. In the root compartment acid phosphatase activity was much higher than alkaline phosphatase activity, and both were slightly enhanced by mycorrhizal infection. Throughout the hyphal compartment, phosphatase activities were distinctly higher in the presence of mycorrhizal plants particularly with a supply of organic P which also increased the percentage of infected root length. Phosphatase activity was strongly correlated with hyphal length which was highest within 10 mm from the root surface. Mycorrhizal inoculation increased plant dry weight. P content and total P uptake irrespectively of P sources and soils. Of the total P uptake mycorrhizal contribution accounted for 24–33% with P supplied in inorganic form, and 48–59% with P supplied in organic form. The results demonstrate a stimulatory effect of organic P in the form of phytate on mycorrhizal infection and hyphal growth as well as the efficient use of phytate-P by phosphatase of mycorrhizal hyphae.

371 citations


Journal ArticleDOI
TL;DR: Compared with control nutrient-sufficient plants, sucrose export in the phloem exudate was drastically decreased by K deficiency and, particularly, by Mg deficiency, whereas P deficiency either had no effect or stimulated Sucrose export.
Abstract: The effect of varied phosphorus (10 and 250 mmol P m -3 ), potassium (50 and 2010 mmol K m -3 ) and magnesium (20 and 1000 mmol Mg m -3 ) supply on sucrose, reducing sugars, amino acids, P, K, and Mg in phloem exudate was studied in bean (Phaseolus vulgaris L.) plants over a 12 d growth period in nutrient solution. Phloem exudates were collected from detached primary leaves using the EDTA-promoted exudation technique. Compared with control nutrient-sufficient plants, sucrose export in the phloem exudate was drastically decreased by K deficiency and, particularly, by Mg deficiency, whereas P deficiency either had no effect or stimulated sucrose export. In Mg-deficient plants the rate of sucrose export was decreased to 10-20% of the control plants

340 citations


Journal ArticleDOI
TL;DR: No practical method is available to maintain the sex-dependent anabolic potential of boars and to suppress androstenone selectively, and it appears, however, that glucocorticoids are more important.

307 citations


Journal ArticleDOI
TL;DR: Fe inefficiency in the maize mutant ys1 is the result of a defect in the uptake system for Fe-phytosiderophores, which results in up to 20 times lower uptake and translocation rates of 59Fe in Ys1 than in Alice or WF9 plants.
Abstract: To determine the Fe inefficiency factors in the maize mutant ys1 (Zea mays L. cv Yellow Stripe), root exudates of Fe-inefficient ys1 and of two Fe-efficient maize cultivars (Alice, WF9) were collected in axenic nutrient solution cultures. Analysis by thin-layer chromatography and high-performance liquid chromatography revealed that under Fe deficiency ys1 released the phytosiderophore 2[prime]-deoxymugineic acid (DMA) in quantities similar to those of Alice and WF9. Under nonaxenic conditions, DMA released by plants of all three cultivars was rapidly decomposed by microorganisms in the nutrient solution. Uptake experiments with 59Fe-labeled DMA, purified from root exudates of either Fe-deficient Alice or ys1 plants, showed up to 20 times lower uptake and translocation of 59Fe in ys1 than in Alice or WF9 plants. The presence of microorganisms during preculture and short-term uptake experiments had no significant effect on uptake and translocation rates of 59Fe in Alice and ys1 plants. We conclude that Fe inefficiency in the maize mutant ys1 is the result of a defect in the uptake system for Fe-phytosiderophores.

221 citations


Journal ArticleDOI
TL;DR: The results strongly suggest that glutamine dipeptide-containing total parenteral nutrition prevents intestinal atrophy and increased permeability associated with glutamine-free parenTERal nutrition.

211 citations


Journal ArticleDOI
01 Aug 1994-Planta
TL;DR: It is concluded that the observed auxin/cytokinin interaction has an important regulatory role to play, not only in apical dominance but in many other correlative events as well.
Abstract: When xylem exudate of previously untreated Phaseolus vulgaris plants was analysed for cytokinins by radioimmunoassay, a low concentration (about 5 ng · ml−1) was found. However, when the plants were decapitated about 16 h before the xylem exudate was collected, an almost 25-fold increase in cytokinin concentration was observed. Twenty-four hours after decapitation this increase even reached 4000‰ compared to control plants. Applying naphthaleneacetic acid (NAA) to the shoot of decapitated plants almost eliminated the effect of shoot tip removal on cytokinin concentration, suggesting that cytokinins in the xylem exudate of intact plants are under the control of the polar auxin transport system. Other xylem constituents, such as potassium or free amino acids did not show this strong increase after decapitation and did not respond to NAA application. It is concluded that the observed auxin/cytokinin interaction has an important regulatory role to play, not only in apical dominance but in many other correlative events as well.

206 citations


Journal ArticleDOI
TL;DR: Zn‐deficiency symptoms appeared first and more severely in Zn‐inefficient Durati, although the concentrations of total Zn in shoot and root tissues were the same in both genotypes.
Abstract: The effect of varied zinc (Zn) and iron (Fe) supply on the release of Zn and Fe mobilizing phytosiderophores from roots was studied in Zn‐efficient Aroona and Zn‐inefficient Durati wheat genotypes (Triticum aestivum cv. Aroona; T. durum cv. Durati) grown under controlled environmental conditions in nutrient solution for 25 days. Phytosiderophore release was determined by the measurement of Zn and Fe mobilizing capacity of root exudates from a Zn‐loaded resin and from freshly precipitated FeIII hydroxide as well as identification by HPLC analysis. Visual Zn‐deficiency symptoms, such as necrotic patches on leaves and reduction in shoot length, appeared first and more severely in Zn‐inefficient Durati, although the concentrations of total Zn in shoot and root tissues were the same in both genotypes. Zinc‐efficient Aroona responded to Zn deficiency by increasing phytosiderophore release usually after 10 days growth in nutrient solution, whereas the phytosiderophore release in Durati remained at a ver...

Journal ArticleDOI
TL;DR: A general strategy in which a polyphasic approach was used to characterize a new species of Lactobacillus pontis is described, and a phylogenetic tree which reflected the relationships of this species to other lactobacilli is constructed.
Abstract: The microflora of sourdough preparations was investigated by examining the physiological characteristics, whole-cell protein patterns, and 16S rRNA sequences of Lactobacillus isolates. Strains isolated from sourdough were placed in the species Lactobacillus brevis, Lactobacillus sanfrancisco, and Lactobacillus reuteri. 16S rRNA sequences were determined for L. brevis, Lactobacillus fructivorans, Lactobacillus fermentum, L. sanfrancisco, and L. reuteri, and oligonucleotide probes for fast specific identification of these sourdough lactobacilli were deduced. The physiological characteristics, protein patterns, and 16S rRNA sequences of these organisms were compared with data for other sourdough lactobacilli and additional reference strains. Strains of a Lactobacillus species were isolated from rye sourdough; these strains may account for most of the flora in sourdough made from wheat or rye. These organisms were differentiated from other sourdough lactobacilli by their protein pattern, 16S rRNA sequence, G+C content, and physiological properties. The 16S rRNA sequence of this species was determined, and we constructed a phylogenetic tree which reflected the relationships of this species to other lactobacilli. This organism is closely related to L. reuteri. A new Lactobacillus species, Lactobacillus pontis, is proposed. The type strain is L. pontis LTH 2587 (= DSM 8475 = LMG 14187). We describe a general strategy in which a polyphasic approach was used to characterize a new species.

Journal ArticleDOI
TL;DR: This study mapped and characterized quantitative trait loci (QTL) affecting testcross performance of maize and discussed the consistency of these QTL across environments and testers.
Abstract: The dissection of quantitative traits into their underlying Mendelian factors has become possible with the aid of molecular markers. In this study, we mapped and characterized quantitative trait loci (QTL) affecting testcross performance of maize (Zea mays L.) and discussed the consistency of these QTL across environments and testers. Two homozygous flint inbred lines were crossed to produce 380 F 2 individuals which were genotyped at 89 restriction fragment length polymorphism (RFLP) marker loci. By selfing the F 2 plants 380 F 2 lines were produced and subsequently crossed to two diverse dent inbred testers (T1 and T2). Each series of testcrosses (TC) was evaluated in field trials with two replications in four environments

Journal ArticleDOI
TL;DR: Starter cultures applied in meat technology may contain moulds, yeasts and bacteria, which represent the most important group of starter organisms, since they are involve in the fermentation of all types of products and contribute to each single aim of the fermentation process.

Journal ArticleDOI
TL;DR: The applicability of the method to various fields of biosciences is demonstrated with the detection and determination of d -amino acids in bacteria, microfungi, higher plants, invertebrates and vertebrates, including man, and in the amino acid-containing Murchison meteorite.

Journal ArticleDOI
TL;DR: Gln and Ala-Gln have trophic effects not only in the ileum, but also in the proximal and distal colon, which could be important during parenteral nutrition when mucosal atrophy may weaken the gut barrier.

Journal ArticleDOI
TL;DR: Sakacin P is a heat-stable, unmodified peptide bacteriocin produced by Lactobacillus sake LTH 673 that may improve the hygienic status of fermented food, i.e. meat products.
Abstract: Summary: Sakacin P is a heat-stable, unmodified peptide bacteriocin produced by Lactobacillus sake LTH 673. The strain was isolated from fermented dry sausages and is well adapted to this habitat. The bacteriocin inhibits the growth of the opportunistic food pathogens Enterococcus faecalis and Listeria monocytogenes and therefore, it may improve the hygienic status of fermented food, i.e. meat products. Oligonucleotide probes were designed from the N-terminal amino acid sequence of sakacin P and used to identify sakP, the structural gene of sakacin P, on the chromosome of L. sake LTH 673. SakP was cloned into Escherichia coli NM554 and the nucleotide sequence of the gene and its adjacent regions were determined. Sakacin P appears to be synthesized as a prepeptide of 61 amino acids which is proteolytically processed to the mature bacteriocin consisting of 43 amino acids. Sequencing of the cloned fragment also revealed the presence of two other open reading frames orfX and orfY, which are located upstream and downstream of sakP, respectively, putatively encoding proteins of 52 and 98 amino acids, respectively. The functions of both ORFs remain unknown. Primer extension analysis revealed a promoter upstream of sakP. Two transcripts of approximately 0.35 and 1.0 kb were detected by Northern hybridization encoding either only sakP, or both sakP and orfY, respectively.


Journal ArticleDOI
TL;DR: Results from this study corroborate the usefulness of RFLPs for the organization of elite barley germplasm and determine RFLP-based genetic similarity estimates between unrelated cultivars within and between the winter and spring barley gerplasm.
Abstract: Restriction fragment length polymorphisms (RFLPs) have been proposed for characterizing genetic diversity of barley (Hordeum vulgare L.) germplasm. Forty-eight (24 winter, 24 spring) cultivars from the European barley germplasm were assayed for RFLPs with 136 clone-enzyme combinations (CEC) (48 DNA clones, three restriction enzymes). Objectives of this study were to (i) assess the amount variation for RFLPs in these materials, (ii) determine RFLP-based genetic similarity estimates between unrelated cultivars within and between the winter and spring barley germplasms, and (iii) examine the usefulness of RFLPs for classification of cultivars from different germplasm pools. Thirty-five DNA clones detected polymorphism with at least one enzyme. For the 62 polymorphic CEC, 58% of all RFLP patterns were common to both winter and spring barley, and about 20% were specific to the cultivars of each group. Genetic similarity (GS) calculated from RFLP data ranged from 0.64 to 0.93 between unrelated pairs of cultivars. Mean GS (MGS) for unrelated cultivar combinations within the group of winter (0.85) and spring (0.84) type cultivars were significantly greater than for winter × spring cultivar combinations (0.76). All winter and spring cultivars except two had a smaller MGS to cultivars from the other group than to unrelated cultivars from the same group. Principal coordinate analysis of GS estimates resulted in a separate grouping of winter and spring cultivars; further subgroups were also apparent for cultivars with a similar pedigree background. Results from our study corroborate the usefulness of RFLPs for the organization of elite barley germplasm.

Journal ArticleDOI
TL;DR: Body weights were recorded at tagging on 1704 one year old presmolts (offspring of 26 males and 115 females) and again after 4, 12, 16, 24 and 27 months in seawater.

Journal ArticleDOI
TL;DR: The wholesomeness of LAB can be extended to fields outside human nutrition, as they may act as probiotics in animal production or as plant protectives in agriculture and thus contribute to healthy raw materials for food production.
Abstract: By tradition lactic acid bacteria (LAB) are involved in the production of fermented foods. These constitute one quarter of our diet and are characterized by a safe history, certain beneficial health effects, and an extended shelf life when compared with raw materials. The various fermenting substrates are habitats for specific LAB that differ in their metabolic potential. The health effects exerted by LAB are the following: 1. Production of lactic acid and minor amounts of acetic and formic acid. These cause: a drop in pH and thereby growth inhibition of food spoiling or poisoning bacteria; killing of certain pathogens; detoxification by degradation of noxious compounds of plant origin (usually in combination with plant-derived enzymatic activities). 2. Production of antimicrobial compounds (e.g. bacteriocins, H2O2, fatty acids). 3. Probiotic effects as live organisms in food. The wholesomeness of LAB can also be extended to fields outside human nutrition, as they may act as probiotics in animal production or as plant protectives in agriculture and thus contribute to healthy raw materials for food production. Modern concepts or perspectives of the application of LAB include the following: 1. Selection of the best adapted and safely performing LAB strains. 2. Selection of strains with probiotic effects. 3. Selection of strains with health-promoting effects (e.g. production of vitamins or essential amino acids, anti-tumour activity). 4. Selection of strains with food protective activities (inhibiting spoilage or food pathogens). These strains can be added to food or used as starters in food fermentations. They may be found as wild-type organisms or can be obtained by genetic engineering.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: The crystal structure of the bromoperoxidase A2 from Streptomyces aureofaciens (ATCC 10762) has been determined by isomorphous replacement and refined to 2.05 A resolution with an R-value of 18.4%.
Abstract: The crystal structure of the bromoperoxidase A2 from Streptomyces aureofaciens (ATCC 10762) has been determined by isomorphous replacement and refined to 2.05 A resolution with an R-value of 18.4%. The enzyme catalyzes the bromination of organic compounds in the presence of bromide and peroxide. The structure confirms the absence of cofactors such as metal ions or haem groups and shows the general topology of the alpha/beta hydrolase fold. The active centre is at the end of a deep pocket and includes a catalytic triad of Ser 98, Asp 228 and His 257. The active centre is connected by a narrow tunnel to a second pocket on the enzyme surface.

Journal ArticleDOI
TL;DR: In this article, the use of simple Fe salts is limited, however, the authors investigated certain pH 6-soluble Fe(III) complexes (Fe-L, where L is an organic tigand) as catalysts for degradation of herbicides.
Abstract: Fenton-type reactions of hydrogen peroxide with Fe compounds generate bydroxyl radical (OH{center_dot}) or other reactive species and are potentially useful for degrading organic contaminants in soil The use of simple Fe salts is limited, however This study investigated certain pH 6-soluble Fe(III) complexes (Fe-L, where L is an organic tigand) as catalysts for degradation of herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and metolachlor (2-chloro-N-[2-ethyl 6-methylphenyl]-N-[2-methoxy-l-methylethyl]acetamide) Reactions were carried out in 1:1 aqueous suspensions of a topsoil (157 g kg{sup -1} organic C) at the natural pH of 57 with herbicides at concentrations representative of a spill (2-3 g kg{sup -1} about 001 mol kg{sup -1}) The two herbicides had contrasting sorption behavior in that 2,4-D was mostly in solution, whereas metotachlor was mostly sorbed The best results were obtained using Fe-nitrilotriscetate (NTA) or Fe-hydroxyethyleniminodiacetate (HEIDA) at 001 mol kg-{sup -1} and [H{sub 2}O{sub 2}]{ge} 05 mol kg{sup -1} The gallic acid complex was less effective In 3 h,{sup 14}C-labeled 2,4-D was quantitatively dechlorinated and partially (15-30%) converted to {sup 14}CO{sub 2}: metolachlor was 93% transformed and 29% dechlorinated Controls using free ligand plus peroxide or peroxide alone gave little or no reaction Fe-L + H{sub 2}O{sub 2} was superior to the Fentonmore » reagent itself (Fe{sup 2+} + H{sub 2}O{sub 2}) The results of this study demonstrate that relatively mild chemical oxidation can be effective for remediation of certain contaminants in soil 23 refs, 2 figs, 6 tabs« less

Journal ArticleDOI
TL;DR: Data indicate that at least two α‐bungarotoxin subtypes are present in the chick optic lobe and operate as ligand‐gated channels and display different agonist sensitivities and kinetics/conductance properties.
Abstract: Two chick optic lobe alpha-bungarotoxin receptor subtypes (alpha 7 and alpha 7-alpha 8) were immunopurified using polyclonal antibodies raised against synthetic peptides of chick alpha 7 and alpha 8 alpha-bungarotoxin receptor subunits. The alpha 7 subtype contained the M(r) 57,000 alpha 7 subunit, and represented 60-70% of the alpha-bungarotoxin receptors; the alpha 7-alpha 8 subtype contained the M(r) 57,000 alpha 7 and alpha 8 subunits, and represented only 20-25% of the receptors. Both subtypes also had an additional M(r) 52,000 subunit. The affinity of these subtypes for alpha-bungarotoxin as well as antagonists was similar. However, the alpha 7-alpha 8 subtype displayed consistently higher affinities for agonists. When reconstituted in planar lipid bilayers, the alpha 7-alpha 8 subtype displayed several conductance states of 10-50 pS; the alpha 7 subtype had only one conductance state of 45 pS. The alpha 7-alpha 8 subtype was activated by lower agonist concentrations than the alpha 7 subtype. When expressed in Xenopus oocytes, the alpha 8 subunit formed functional homomeric receptors that desensitized rapidly. These channels were blocked by alpha-bungarotoxin and displayed a higher affinity for agonists than the alpha 7 homomeric receptor. Taken together, these data indicate that at least two alpha-bungarotoxin subtypes are present in the chick optic lobe. They operate as ligand-gated channels and display different agonist sensitivities and kinetics/conductance properties.

Journal ArticleDOI
15 Nov 1994-Cancer
TL;DR: This study was performed to evaluate the possible positive effects of glutamine supplementation in catabolic hematologic patients and found it possible that glutamine‐supplemented total parenteral nutrition improved the nitrogen balance incatabolic situations.
Abstract: Background. Glutamine-supplemented total parenteral nutrition (TPN) improved the nitrogen balance in catabolic situations. In animal studies, parenteral glutamine supplementation appeared to maintain gut integrity. This study was performed to evaluate the possible positive effects of glutamine supplementation in catabolic hematologic patients. Methods. This was a prospective double-blind placebo-controlled pilot study, in which 20 treatment cycles in unselected hematologic patients with intensive chemotherapy were studied. Glutamine was given as a dipeptide. Patients were randomized per treatment cycle to receive isonitrogenous TPN (0.272 g nitrogen/kg of body weight) and isoenergetic TPN (2200 kcal NPE/day) without or with 40 g L-alanyl-L-glutamine (26 g glutamine) until the neutrophil count was greater than 0.5 X 109/L. The daily oral food intake was recorded and analyzed carefully, Toxicity grades for performance status, mucositis, and diarrhea were scored according to the World Health Organization classification. Results. No differences in neutropenic period, fever, extra antibiotics, and toxicity scores were observed, except for a gain in body weight per treatment cycle in favor of the glutamine-supplemented TPN. No side effects or allergic reactions were noted after the dipeptide administration. Conclusion. Supplementation of glutamine dipeptide was safe but had no significant positive clinical effect. Cancer 1994; 742879-84.

Journal ArticleDOI
TL;DR: It is demonstrated that odorants stimulate translocation of GRK3 from cytosol to membranes in isolated rat olfactory cilia, suggesting that beta gamma-subunits may physiologically regulate a G protein-coupled receptor kinase and that enzyme translocation may be a general and required feature of the activity of some members of this enzyme family.

Journal ArticleDOI
TL;DR: Considering the hygienic aspects of the production and use of animal wastes, processes of self-disinfection of manure and livestock slurry during storage as a means of reducing the amounts of chemical disinfectants used, of reducing environmental pollution, and of studying the application of biotechnological methods to disinfect manure and cattle slurry are of particular importance.
Abstract: Regarding the hygienic aspects of the production and use of animal wastes, further research on the following aspects is essential: pathogenic agents present in residues of animal production in the context of transmissible multifactorial diseases and the epidemiology of pathogens under different ecological conditions; recycling of toxic agents, e.g., copper, selenium and iodine, in animal wastes in the context of the food chain from soil to humans; hygienic effects of animal wastes on water as regards the standards required by medical authorities; effects of agents used to increase animal production, or used for medicinal purposes, which are present as residues in animal excreta and may be hazardous to public health; effects of animal excreta on microbiological processes in the soil; effects of dust and airborne microbial emissions from animal production, and finally, processes of self-disinfection of manure and livestock slurry during storage as a means of reducing the amounts of chemical disinfectants used, of reducing environmental pollution, and of studying the application of biotechnological methods to disinfect manure and livestock slurry, this study being of particular importance.

Journal ArticleDOI
TL;DR: The depletion oforganic P depended on the soil type, hyphal length density, phosphatase activities and the amount of organic P present in the system, which caused depletion of V A-mycorrhizal hyphae throughout the hyphal compartment.
Abstract: In a pot experiment wheat (Triticum aestivum L.) was grown under axenic conditions in two soils differing in organic matter and phosphorus contents. The pots were separated by 30 .urn nylon nets and a 0.45 .urn membrane into five compartments, a central one for root growth, two adjacent to the central compartment for hyphal growth and two outer ones for control. The treatments consisted of sterilized soil, supply of organic (Na-phytate) or inorganic phosphorus (P) and of soil either non-inoculated or inoculated with Glomus mosseae. Shoot dry weight increased by mycorrhizal inoculation in the range between 2.2 and 4.5 g pot−1 depending on the soil and treatment. Organic P was depleted by V A-mycorrhizal hyphae throughout the hyphal compartment (15 mm). The maximum depletion was 106 mg kg−1 soil within a 0.5 mm distance from the root surface. The depletion of organic P depended on the soil type, hyphal length density, phosphatase activities and the amount of organic P present in the system. The max...

Journal ArticleDOI
TL;DR: The triphenyltetrazolium chloride (TTC) method described by Thalmann and Spothelfer-Magana as mentioned in this paper and the iodonitrotetric acid (INT) method used for measuring soil dehydrogenase activity, have been modified to overcome some methodical shortcomings.
Abstract: The triphenyltetrazolium chloride (TTC) method described by Thalmann (1968) and the iodonitrotetrazolium chloride (INT) method described by Spothelfer-Magana and Thalmann (1992), used for measuring soil dehydrogenase activity, have been modified to overcome some methodical short-comings. Absorption maxima of 485 nm for triphenylformazan dissolved in acetone, 491 nm for iodonitrotetrazolium formazan (INTF) dissolved in tetrahydrofuran and 455 nm for INTF dissolved in N,N-dimethylformamide are recommended for measuring wavelengths. Extracting triphenylformazan twice with acetone is less toxic and proved to be at least as efficient as extraction with a mixture of 90% acetone and 10% carbon tetrachloride (Thalmann 1968 method). Tetrahydrofuran and dimethylformamide were equally good in extracting INTF from soils, but the former was less toxic. Anaerobic incubation resulted in the formation of higher amounts of triphenylformazan and INTF as well as reduced standard error. Both TTC and INT reduction showed high reproducibility and good differentiation of the microbial activity of six soils. For several reasons (more easily determined substrate dose depending on different soil types, better reduction, shorter incubation time), INT reduction seems to be a more suitable method of measuring soil microbial activity than TTC reduction.

Journal ArticleDOI
TL;DR: Free D-amino acids (D-AA) were detected as native constituents in juices of vegetables (cultivars of cabbage, tomato, carrot, garlic) and fruits (organes, clementine, grapefruit, lemon, apples, pear, grapes) using gas chromatography or high-performance liquid chromatography (LC) as mentioned in this paper.
Abstract: Free D-amino acids (D-AA) were detected as native constituents in juices of vegetables (cultivars of cabbage, tomato, carrot, garlic) and fruits (organes, clementine, grapefruit, lemon, apples, pear, grapes) using gas chromatography (GC) or high-performance liquid chromatography (LC). For investigation by GC, AA enantiomers were converted into theirN(O)-pentafluoropropionyl 2-propyl esters and resolved on a Chirasil-L-Val capillary column. For determination by LC, precolumn derivatization of AA enantiomers usingo-phthaldialdehyde together with the chiral thiolsN-isobutyryl-L-cysteine orN-isobutyryl-D-cysteine and fluorescence detection of the diastereomeric isoindole derivatives, resolvable on an octadecylsilyl stationary phase, were used. D-Ala (0.6–3.8%) was detected in all freshly pressed plant juices usually in the highest relative amounts. Other D-AA detected were D-Asx (0.1–1.9%), D-Glx (0–1.3%), D-Ser (0–1.7%), D-Arg (0.4–1.2%, in grapes, orange, grapefruit, and clementine) and D-Leu and D-Val (1% in cabbage). Absolute amounts of native D-AA were totally 28–57 μmol L−1 in fruit juices, 14.5 μmol L−1 in a tomato juice and 8.5 μmol L−1 in a carrot juice.