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1.
A laboratory method for assessing the toxicity of stomach poisons to slugs   总被引:1,自引:0,他引:1  
A method is described that allows the toxicity of stomach poisons to the grey field slug, Agriolimax reticulatus (Muller), to be measured in the laboratory. The relative toxicities of three commonly used molluscicides, as expressed by the median lethal dose values, were: sodium pentachlorophenate most toxic with a median value of 22·9 ± 2·5 μg/slug, metaldehyde next with one of 85·2 ± 4·0 μg/slug, and copper sulphate least toxic with one of 129·2 ± 5·9 to 131·6 ± 5·6 μg/slug. The technique allows a given dose of any poison, however repellent, to be administered, but does not measure the repellency or attractiveness.  相似文献   

2.
Stimulation and inhibition of photosynthesis inHydrilla verticillata Presl. with quinine sulphate and quinine alkaloid with concentrations ranging between 0·001 and 100 ppm was observed. Quantitative measurements of photosynthesis were done by a microburette (Audus 1940) and qualitative estimations by the modified apparatus byZutshi (1965a). Maximum inhibition of 50% and 34% is obtained with 100 ppm of quinine sulphate and quinine alkaloid respectively. The inhibition is due to the adverse effect on the pigment system particularly on carotene (Zutshi 1963). Forty percent stimulation of photosynthesis is obtained with 0·01 ppm quinine sulphate and 12·5% with 0·001 ppm quinine alkaloid. Difference in the biological activity of these two alkaloids is due to their different chemical structure and purity.  相似文献   

3.
Summary Laboratory studies to determine the tolerance of an isolate ofAlternaria tenuis causing a black core rot of mandarin oranges (Citrus reticulata) have shown that presence of low amounts of manganese, zinc, iron, copper, boron, and molybdenum in a synthetic medium stimulated growth and sporulation of the fungus. Concentrations of 20 ppm or more of copper sulphate, boric acid, and ammonium molybdate, however, caused significant reduction of growth. Conidia of the fungus were very sensitive to even low amounts of copper, zinc, and iron. Copper sulphate was most toxic to spore germination followed, in order of inhibitory effect, by zinc sulphate, ferrous sulphate, and boric acid. Ammonium molybdate and manganese sulphate were stimulatory to spore germination at 5 ppm. There was a positive correlation between percentage of spore germination and average length of germ tubes in different concentrations of various chemicals. The possibility of using copper sulphate, zinc sulphate, and ferrous sulphate as spray materials for trees and as dip for ripe fruits to prevent black core rot are discussed.Assoc. Professor and Research Assistant, respectively. Publication under journal series No. 27 from Experiment Station, U.P. Agricultural University.  相似文献   

4.
Aims: To isolate and characterize copper‐resistant halophilic bacteria from the polluted Maruit Lake, Egypt and identify the role of plasmids in toxic metal resistance. Methods and Results: We isolated strain MA2, showing high copper resistance up to the 1·5 mmol l?1 concentration; it was also resistant to other metals such as nickel, cobalt and zinc and a group of antibiotics. Partial 16S rRNA analysis revealed that strain MA2 belonged to the genus Halomonas. Copper uptake, measured by atomic absorption spectrophotometery, was higher in the absence of NaCl than in the presence of 0·5–1·0 mol l?1 NaCl during 5–15 min of incubation. Cell fractionation and electron microscopic observation clarified that most of the copper accumulated in the outer membrane and periplasmic fractions of the cells. Plasmid screening yielded two plasmids: pMA21 (11 kb) and pMA22 (5 kb). Plasmid curing resulted in a strain that lost both the plasmids and was sensitive to cobalt and chromate but not copper, nickel and zinc. This cured strain also showed weak growth in the presence of 0·5–1·0 mol l?1 NaCl. Partial sequencing of both plasmids led to the identification of different toxic metals transporters but copper transporters were not identified. Conclusions: The highest cell viability was found in the presence of 1·0 mol l?1 NaCl at different copper concentrations, and copper uptake was optimal in the absence of NaCl. Plasmid pMA21 encoded chromate, cobalt, zinc and cadmium transporters, whereas pMA22 encoded specific zinc and RND (resistance, nodulation, cell division) efflux transporters as well as different kinds of metabolic enzymes. Copper resistance was mainly incorporated in the chromosome. Significance and Impact of the Study: Strain MA2 is a fast and efficient tool for copper bioremediation and the isolated plasmids show significant characteristics of both toxic metal and antibiotic resistance.  相似文献   

5.
Aims: In the United States, carbadox and copper sulfate are growth promoters commonly used in combination in nursery swine diets. Our aim was to determine how selected dietary additives affect selected bacterial populations and pathogens in nursery swine, and compare to larch extract, which contains potential antibacterial activities. Methods and Results: Piglets were weaned and sorted into one of the four treatments: (i) basal diet without antimicrobials; (ii) basal diet with carbadox + copper sulfate; (iii) basal diet + 1000 ppm larch extract; or (iv) basal diet + 2000 ppm larch extract. Diets were fed for a 4‐week period after weaning. In both trials, the carbadox + copper sulfate group consumed more feed over the 4‐week period relative to the other three diet groups (P < 0·05), but did not gain significantly more weight. Faecal shedding of Salmonella spp. was not affected by dietary supplement in either trial, but faecal shedding of Campylobacter spp. was the lowest for the carbadox + copper sulfate diet. In faecal samples collected at the end of each trial, Lactobacillus spp. cell counts for the basal and larch extract diets were nearly 1·0 log10 g?1 faeces greater (P < 0·05) than the carbadox + copper sulfate group, whereas the coliforms and Escherichia coli were nearly 1·0 log10 g?1 faeces lower (P < 0·05). Conclusions: Compared to basal fed animals, supplementation with carbadox + copper sulfate significantly altered faecal E. coli, coliform bacteria and Lactobacillus spp. Larch extract has no benefit up to 0·2% of diet in regard to pathogen shedding, whereas carbadox + copper sulfate decreased faecal shedding of Campylobacter spp. Significance and Impact of the Study: Current swine management practices in the United States may be beneficial to managing Campylobacter spp. shedding in nursery swine, but also result in significant changes in the resident gastrointestinal microflora.  相似文献   

6.
Synthesis and properties of lunularic acid   总被引:1,自引:0,他引:1  
Lunularic acid, a natural plant growth inhibitor, has been synthesized. A high concentration (10–30 ppm) effectively inhibited the elongation of root coleoptiles caused by 0·3 and 0·03 ppm indole-3-acetic acid.  相似文献   

7.
A study was carried out on 20 water bodies of the same origin in southern Poland. The study objectives included the assessment of toxic metal contamination in the bottom sediments of the water bodies in comparison with the geochemical background and sediments found in the substrate (i.e., vicinity) of the water bodies (i.e., the formations present in the surroundings of the water body itself), thus demonstrating the scale of anthropogenic enrichment of bottom sediments with toxic metals and assessing the cumulative impact on water bodies. The following amounts of toxic metals were found in the bottom sediments of the water bodies examined: 181.7–35200.0 ppm for zinc, 33.3–1648.8 ppm for lead, 1.8–359 ppm for cadmium, 14.0–271.5 ppm for copper, 45.3–167.5 ppm for chromium, and 12–128.5 ppm for nickel. Ratios of the values measured to the geochemical background were as follows: 0.7–135.9 (Zn), 0.6–53.0 (Pb), 0.7–143.6 (Cd), 0.9–18.1 (Cu), 5.0–18.6 (Cr), 1.1–11.7 (Ni).  相似文献   

8.
Twelve amino acids and amides at 0·1 to 0·75 or 1·0% in 35% sucrose solution were individually tested for their rôle in phagostimulation, growth, and survival in Acyrthosiphon pisum. Leucine and phenylalanine were phagostimulatory at all concentrations tested, tryptophan and valine at 0·1, 0·2, and 0·5%, and threonine at 0·1% only. Methionine was reported earlier by us to be phagostimulatory at 0·05 to 0·5%. Histidine and isoleucine had no effect, whereas arginine and lysine HCl reduced uptake when compared to sucrose alone. The non-essential amino acids, canavanine sulphate and glutamine, reduced uptake at all concentrations, whereas homoserine was phagostimulatory at 0·1 and 0·75%.Arginine, canavanine sulphate, glutamine, histidine, homoserine, isoleucine, leucine, and valine increased weight and prolonged survival, whereas lysine HCl, phenylalanine, threonine, and tryptophan neither promoted growth nor increased survival. Radioactive leucine (14C(U)) was incorporated into the protein fraction of the larval body and exuviae indicating that it took part in protein synthesis. This seems to be the first report in insects where peptide or protein synthesis occurred from single amino acids in sucrose.  相似文献   

9.
One hundred and four rabbits, five weeks old at the beginning of the experiment, were divided into four groups according to a feed additive treatment. Rabbits of the 1st, 2nd, 3rd and 4th group were fed a basal granulated feed (control), basal feed supplemented with CuSO4 · 5H2O at 50mg Cu · kg‐1, basal feed supplemented with 150mg Cu · kg‐1, and the latter feed supplemented with 100mg · kg‐1 vitamin E, respectively. The duration of the experiment was 42 days. Addition of Cu at 150mg · kg.‐1 increased weight gain non‐significantly by 9.1%. This effect was the most pronounced in the first two weeks of fattening. The lowest mortality was observed in rabbits fed the highest amount of additives (7.7% vs. 19.2% in the control). Rabbits were slaughtered at the age of 11 weeks. Neither treatment influenced proportions of saturated, monounsaturated and polyunsaturated fatty acids in lipids extracted from the loin and hindleg muscles. In rabbits fed the highest amount of copper and vitamin E, the cholesterol concentration was significantly decreased by 13.6% and 17.9% in the loin and hindleg meat, respectively. Effects of Cu added at 50mg · kg‐1 were marginal. Copper had no effect on the oxidative stability of meat, measured as thiobarbituric acid‐reactive substances in meat stored at 4°C for 0, 3 and 8 days. Vitamin E added in excess of nutritional requirement improved the oxidative stability of meat. In copper‐fed rabbits, Cu accumulated in the liver, but not in muscles. Feeding of the basal feed for 7 days to rabbits previously fed copper sulphate decreased the hepatic Cu concentration by 14.0 to 24.4%  相似文献   

10.
《Biological Wastes》1987,19(2):79-90
A full-scale, completely-mixed digester, with a liquid capacity of 587 m3, was constructed to process the manure from 70 000 caged layers. Biogas from the digester was used as fuel for an engine/generator set. The operating temperature was maintained at 35°C using waste heat from the engine. The digester was operated on a 22–24 day HRT. Digester influent averaged 5·90% TS, 5250 ppm TKN, and 3790 ppm NH3N. Digester effluent averaged 3·11% TS, 5090 ppm TKN, and 4060 ppm NH3N.Sustained operation of the digester was achieved during the period of study (8/83−4/85). During this period biogas production averaged 0·38 m3 kg−1 VS added (0·58 m3 kg−1 VS destroyed). The CH4 content averaged 58·0%. The major operational problem encountered was grit accumulation in the digester. This problem was reduced by settling most of the grit from the manure prior to the digester. Biogas production was reduced when concentrated lagoon-liquid was used as make-up water. Approximately 22% of the electricity produced was required for operating the system.  相似文献   

11.
Copper fungicides and mycoinsecticides based on entomopathogenic fungi Beauveria spp. are the most common pesticides used in organic crop production systems. The in vitro effects of the copper fungicides copper oxide, copper hydroxide, copper oxychloride, copper sulphate, dicopper chloride trihydroxide and tribasic copper sulphate were investigated for mycelial growth, sporulation and conidial germination of the ATCC 74040 commercial strain of Beauveria bassiana. Mycelial growth was evaluated on potato dextrose agar plates with 100%, 75%, 50%, 25%, 12.5%, 6.25% and 0% of the recommended application rates of each fungicide at 15 and 25°C. Sporulation and conidial germination were determined at the recommended field doses of each fungicide at 25°C. All copper fungicides had fungistatic or fungicidal effects on B. bassiana that varied according to the dose. Only in two cases, copper oxide at 15°C and copper hydroxide at 25°C, at the lowest concentration of 6.5%, was mycelial growth not statistically significantly inhibited. Inhibition of mycelial growth depended both on the fungicide and its concentration, and partly on temperature. Both sporulation and conidial germination of B. bassiana were significantly inhibited by all fungicides. All fungicides inhibited the sporulation in a similar way (99.8%–100%). With the exception of copper oxychloride (inhibition, 13.6%), the other fungicides showed high detrimental effects on conidial germination (inhibition, 91.7%–100%). The fungus was strongly affected by some fungicides even at the lowest doses. The biological index used for the B. bassiana with copper fungicides ranged from 0.6 (copper sulphate) to 18.1 (copper oxychloride). Therefore, the tested fungicides were classified into the upper half of the highly toxic (T) category and are considered incompatible with the entomopathogenic fungus B. bassiana strain ATCC 74040 under in vivo experimental conditions. These results need to be further verified in vitro under both greenhouse and open-field conditions.  相似文献   

12.
In comparative tests using individually caged wild house-mice (Mus musculus L.) coumatetralyl at 0·05 % in an oatmeal bait-base was found to be as acceptable as plain bait and as acceptable and as toxic as warfarin at 0·025% (the standard dosage). It was less readily accepted at 0·1 or 0·2% in the same bait-base or at 0·05% in a proprietary bait formulation. In further tests with suspected warfarin-resistant mice, coumatetralyl at either 0·05, 0·1 or 0·2% proved more toxic than warfarin at either 0·025, 0·1 or 0·2% respectively. However, some individuals survived 21 days feeding on each of these concentrations of coumatetralyl and, in field and laboratory trials, 0·05 and 0·1% coumatetralyl baits failed to control warfarin-resistant mouse populations after 3–5 weeks. It is concluded that coumatetralyl is a suitable alternative poison to warfarin for use against mice that are susceptible to anti-coagulants but that it is unlikely to control warfarin-resistant populations effectively.  相似文献   

13.
(1) Dopamine, β-hydroxylase (EC 1.14.2.1) was purified from bovine adrenal medullae according to the method of Foldes , Jeffrey , Preston and Austin (1972). (2) The kinetics, pH optimum and the effect of Cu2+ ions on the purified enzyme were found to resemble those of the enzyme isolated by more involved procedures. (3) The sedimentation coefficient (s20) of the homogeneous enzyme in 10 mM-phosphate buffer, pH 7·2, containing 0·1 M-NaCI was found to be 10·24 ± 0·12 (S.E.M. of 10 determinations). (4) The effect of pH on the mol. wt. of the enzyme was investigated and no large deviation was found from the native mol. wt. of 290,000 in the pH range 3·9 to 11·1. (5) The amino acid analysis of dopamine β-hydroxylase is presented, and is contrasted to that of chromogranin A purified from the same chromaffin granule lysate. (6) Treatment with either 8 M-urea or 0·1% (w/v) sodium dodecyl sulphate was found to dissociate the enzyme into three similar, non-active subunits, each of mol. wt. of the order of 100,000.  相似文献   

14.
This study presents data collected over a 6 year period on the effects of extremely low‐frequency magnetic fields (MFs) (1·4–1·6 µT, 500 Hz and 1·4–1·6 µT, 72·5 Hz) and MFs in combination with other environmental stressors (elevated temperature, 0·01 mg l?1 trichlorfon, 0·01 mg l?1 copper sulphate pentahydrate) on roach Rutilus rutilus embryos. Effects were studied during different stages of early development. Rutilus rutilus were raised in ponds for 4 months after exposure to MFs. The mass, standard length (LS) and morphological characteristics of underyearlings which were exposed as embryos were recorded. An increase in embryo mortality and a decrease in LS and mass indices in underyearlings were noted after they had been exposed to a combination of MFs and different adverse environmental factors. In addition, exposure to MFs led to changes in the total number of vertebrae and the number of seismosensory system openings in the mandibular bones of underyearlings. MFs of different frequency caused both increases (500 Hz) and decreases (72·5 Hz) in morphological diversity. The stressors used in this study, however, did not increase the fluctuating asymmetry of bilateral morphological characteristics. The possible microevolutionary effects of exposure to MFs alone and in combination with other adverse environmental factors upon natural fish populations are discussed.  相似文献   

15.
When tributyltin oxide (TBTO) was tested by British Standard 3653 against Lyctus brunneus, 0·5 % solution, equivalent to 0·72 g/m2 surface application, gave almost complete protection. Tests to BS 3651, using larvae of Anobium punctatum transferred into fully impregnated wood gave toxic limits of 1·39–2·93 kg/m3 TBTO when benzene was used as diluent. The use of white spirit as diluent gave lower toxic limits, probably due to combined toxic action of TBTO and white spirit residues. TBTO appears to have no contact action against the insects tested. Probit analysis of the test with A. punctatum gave an LD 50 of 0·254 kg/m3 and an LD99 of 3 kg/m3. The advantage of treating results by probit analysis rather than by deriving ‘toxic limits’ is discussed.  相似文献   

16.
Aims: To investigate the effect of lactic acid (LA), copper (II), and monolaurin as natural antimicrobials against Cronobacter in infant formula. Methods and Results: The effect of LA (0·1, 0·2 and 0·3% v/v), copper (II) (10, 50 and 100 μg ml?1) and monolaurin (1000, 2000, and 3000 μg ml?1) suspended into tween‐80? or dissolved in ethanol against Cronobacter in infant formula was investigated. Reconstituted infant formula and powdered infant formula were inoculated with five strains of Cronobacter spp. at the levels of c. 1 × 106 CFU ml?1 and 1 × 103 CFU g?1, respectively. LA at 0·2% v/v had a bacteriostatic effect on Cronobacter growth, whereas 0·3% v/v LA resulted in c. 3 log10 reduction. Copper (II) at the levels of 50 μg ml?1 and 100 μg ml?1 elicited c. 1 and 2 log10 reductions, respectively. The combination of 0·2% LA and 50 μg ml?1 copper (II) resulted in a complete elimination of the organism. Monolaurin exhibited a slight inhibitory activity against Cronobacter (c. 1·5 log10 difference) compared to the control when ethanol was used to deliver monolaurin. Conclusions: A complete elimination of Cronobacter was obtained when a combination of sublethal concentrations of LA (0·2%) and copper (II) (50 μg ml?1) was used. Significance and Impact of the Study: The use of the synergistic interactive combination of LA and copper (II) could be beneficial to control Cronobacter in the infant formula industry.  相似文献   

17.
—Tyramine β-hydroxylase catalyzes the biosynthesis of octopamine in the lobster nervous system. This enzyme has been characterized and a rapid microassay, based on the enzymic release of tritiated water from [1,2-(side chain) 3H] tyramine, has been developed. Lobster tyramine β-hydroxylase resembled mammalian dopamine β-hydroxylase. The most conspicuous differences were that the lobster enzyme was inhibited by anions, particularly fumarate, and had a higher affinity for substrates. Tyramine β-hydroxylase activity was present in both particulate and soluble fractions of homogenates of the lobster nervous system. Bound activity, extracted by repeated freezing and thawing, was partially purified. The enzyme had the following properties: (1) The optimum pH for the conversion of tyramine to octopamine was 7·4. (2) The apparent Michaelis constant for tyramine was 0·15 mm and for ascorbic acid was 0·2 mm at pH 6·6. (3) The purified enzyme was inhibited by salts; the degree of inhibition was sensitive to the anion and decreased in the order chloride ? fumarate > sulphate > acetate. (4) Tyramine β-hydroxylase was inhibited by metal chelating agents and by cupric sulphate at concentrations greater than 10?4m ; N-ethylmaleimide had no significant effect on activity in concentrations up to 3 mm . (5) The purified enzyme also β-hydroxylated dopamine to form norepinephrine, with an apparent Michaelis constant of 0·24 mm . This activity co-purified with tyramine β-hydroxylase, suggesting that a single enzyme catalyzed both reactions.  相似文献   

18.
The process parameters were optimized to obtain enhanced enzyme activity from the fungus Phoma herbarum isolate KU4 using rice straw and saw dust as substrate under solid-state fermentation using Response surface methodology (RSM). Genetic algorithm was used to validate the RSM for maximum laccase production. Six variables, viz., pH of the media, initial moisture content, copper sulphate concentration, concentration of tannic acid, inoculum concentration and incubation time were found to be effective and optimized for enhanced production. Maximum laccase production was achieved by RSM at pH 5·0 and 86% of initial moisture content of the culture medium, 150 µmol l−1 of CuSO4, 1·5% tannic acid and 0·128 g inoculum g−1 dry substrate inoculum size on the fourth day of fermentation. The highest laccase activity was observed as 79 008 U g−1, which is approximately sixfold enhanced production compared to the unoptimized condition (12 085·26 U g−1).  相似文献   

19.
The fungicide Dithane M-45 when applied to the soil was regularly and significantly toxic to the total count of fungi at all doses used (4·48, 22·4 and 44·8 mg active ingredient per kg dry soil). The toxicity was regularly increased with dose and persisted till the end of the experiment (15 weeks). When Dithane M-45 was incorporated into the agar medium all test fungi were eliminated by the high dose (24·0 ppm). The low and medium doses were tolerated by some fungi. The decay of filter paper buried in the fungicide-treated soil was significantly reduced by the high dose after 1 and 3 weeks of incubation, while the decay of filter paper treated with this fungicide and buried in untreated soil was significantly retarded by the high dose only after all experimental periods of incubation (up to 15 weeks). The growth and sporulation of nine test fungi were eliminated by the three doses of Dithane M-45 except Chaetomium globosum, Fusarium moniliforme and Trichoderma viride which could grow restrictedly at the low dose only. Production of endo-1,4β-d-glucanase and mycelial dry weight were not significantly affected by the three doses in the case of Aspergillus niger, and by the low dose in the case of Alternaria alternata, Fusarium solani and Myrothecium verrucaria. In the case of other test fungi and other doses, endo-1,4β-glucanase production and mecelial dry weight were significantly inhibited.  相似文献   

20.
Aims: The efficacy of a commercial seed washer and 1 and 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for reducing Salmonella on alfalfa seeds was investigated. Methods and Results: Alfalfa seeds were inoculated with Salmonella Stanley to achieve c. 5 log CFU g?1. Seeds were then treated with 1 or 3% peroxyacetic acid or 20 000 ppm calcium hypochlorite for 15 min in a commercial seed washer that uses air to enhance contact of the sanitizer with the seed. Experiments were also conducted using industry and laboratory methods. An c. 1‐log reduction in number of Salm. Stanley was demonstrated regardless of the chemical treatment or method of treatment. Although this 1‐log reduction was significant (P < 0·05), differences among the treatments were not significant. Treating the seed with 1 and 3% peroxyacetic acid resulted in similar Salm. Stanley reductions of 1·77 and 1·34 log, respectively, not being statistically significant (P > 0·05). Conclusions: These results suggest that under conditions tested, 1 or 3% peroxyacetic acid solutions are equally effective as 20 000 ppm of Ca(OCl)2 in the reduction of Salm. Stanley on alfalfa seed when used in conjunction with a commercial seed washer. Significance and Impact of the Study: A 1% peroxyacetic acid solution could potentially be used in place of 20 000 ppm of Ca(OCl)2 for treatment of seeds used for sprouting. The commercial seed washer did not enhance removal of Salm. Stanley from alfalfa seeds, but did facilitate removal of excess soil from seeds.  相似文献   

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