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32 results on '"Li, D.P."'

9. Random amplified polymorphic DNA markers reveal a high degree of genetic diversity in the entomopathogenic fungus Metarhizium anisopliae var. anisopliae

Author

Fegan, M., Manners, J.M., Maclean, D.J., Irwin, J.A. G., Samuels, K.D.Z., Holdom, D.G., and Li, D.P.

Subjects
Fungi, Pathogenic -- Genetic aspects, Gene amplification -- Observations, Insects -- Host plants, Genetic markers -- Usage, Biological sciences
Abstract

Random amplified polymorphic DNA (RAPD) markers were employed to examine Metarhizium anisopliae isolates from insects derived from various sugarcane-growing regions of Queensland to study genetic diversity in these organisms. The study employed thirty isolates of M. anisopliae var. anisopliae. The isolates studied belonging to the species M. anisopliae revealed genetic diversity.

Published
1993

16. Effects of the nitrification inhibitor DMPP on soil bacterial community in a Cambisol in northeast China

Author

Dong, X.X, Zhang, L.L, Wu, Z.J, Li, D.P, Shang, Z.C, and Gong, P

Subjects
ammonium-oxidizing archaea, soil total bacteria, ammonium-oxidizing bacteria, Nitrification inhibitor, long-term experiment
Abstract

A long-term experimental site was built to study effects of the nitrification inhibitor 3, 4-dimethylpyrazole phosphate (DMPP) on a bacterial population's diversity and activity in a Cambisol in northern China. Treatments included no fertilization (CK), application of urea alone (U), and application of urea plus DMPP (UD). The annual application rate for the urea was 180 kg N ha-1, and that of the DMPP was 1.8 kg ha-1. The diversity and composition of the overall soil bacterial community were analyzed using pyrosequencing, and the abundances of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were analyzed using a real-time polymerase chain reaction (RT-PCR) assay. The dominant phyla were Proteobacteria, Acidobacteria, Actinobacteria, Bacteroidetes, Gemmatimonadetes, Chloroflexi, Firmicutes, and Planctomycetes in all of the samples. However, compared with treatment U, the relative abundance and identities of the dominant phyla that were increased in treatment UD were more similar to those of the CK treatment. DMPP significantly reduced the targeted ammonia oxidizing bacterial abundance, and the soil potential nitrification rate had a significant positive correlation with the amoA gene copy number of the AOB (r=0.685, n=9, p

Published
2013

17. The activity and kinetic parameters of oxidoreductases in phaeozem in response to long-term fertiliser management

Author

Shang, Z.C, Zhang, L.L, Wu, Z.J, Gong, P, Li, D.P, Zhu, P, and Gao, H.J

Subjects
dehydrogenase, Enzymatic kinetic parameters, catalase, phaeozem, fertilisation
Abstract

This study describes the effects of balanced versus nutrient-deficient fertilisation on soil nutrient content and selected oxidoreductase activity and kinetic parameters in a long-term (28 years) field experiment conducted using a phaeozem type soil in the Jilin Province of northeast China. As compared to no or unbalanced fertilisation, balanced fertilisation improved the overall chemical fertility of the soil and significantly increased the activities and Vmax values of soil dehydrogenase and catatase. Compared with control (CK), unbalanced fertilisation (with the exception of P deficiency) significantly increased the total carbon content and soil dehydrogenase activity but had less of an effect on the Vmax of the enzyme, whereas the soil catalase activity and its Vmax were less affected under unbalanced fertilisation conditions. The Km value of soil dehydrogenase increased with the application of chemical NPK combined with farmyard manure but decreased under the application of NPK, NP, and PK. The Km value of soil catalase decreased under the application of NK and showed little difference between CK and the other fertilisation treatments. The variations in the activities and kinetic parameters of the enzymes revealed the benefits of long-term balanced fertilisation, particularly the combined application of chemical and organic fertilisers, by improving the chemical and biological fertility of phaeozem. The results also indicated that unbalanced fertilisation with P deficiency (NK) could enhance phaeozem quality, but this effect was limited.

Published
2012

19. Calcination-temperature-dependent gas-sensing properties of mesoporous α-Fe2O3 nanowires as ethanol sensors.

Author

Li, X.Q., Li, D.P., Xu, J.C., Han, Y.B., Jin, H.X., Hong, B., Ge, H.L., and Wang, X.Q.

Subjects
*CALCINATION (Heat treatment), *GAS detectors, *NANOWIRES, *MESOPOROUS materials, *BAND gaps
Abstract

The mesoporous α-Fe 2 O 3 nanowires (NWs) were successfully synthesized by changing the calcination temperature from 550 to 750 °C (marked NWs-550, NWs-650 and NWs-750) via using SBA-15 silica as the hard templates with the nanocasting method. The characterization results indicated that the bandgap of the as-prepared samples hardly changed and the high BET surface areas changed a little with the calcination temperature from 550 to 750 °C. Mesoporous α-Fe 2 O 3 NWs had been found to possess the remarkable gas-sensing performance to ethanol gas. The gas-sensing behavior indicated that α-Fe 2 O 3 NWs-650 exhibited the higher response than that of α-Fe 2 O 3 NWs-550 and α-Fe 2 O 3 NWs-750. The calcination-temperature-dependent gas-sensing properties were mainly attributed to the competition of surface defects and body defects by the crystallization temperature. The lower calcination temperature could create more surface defects to improve the gas-sensing response, while the higher temperature would reduce the body defect and make the charge carriers transport easily. As the result, the suitable calcination temperature was desired to optimize the defects of nanostructures to improve the gas sensitivity. [ABSTRACT FROM AUTHOR]

Published
2017
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32. Effects of Nutrients on Colony Formation, Growth, and Sporulation of Metarhizium anisopliae(Deuteromycotina: Hyphomycetes)

Author

Li, D.P. and Holdom, D.G.

Abstract

In order to examine some possible effects of plant root exudates on Metarhizium anisopliae, we examined the effects of a range of carbon and nitrogen sources and vitamins on colony formation, mycelial growth, and sporulation of two isolates (EF25 and EF55). We also hoped to provide some information relevant to culturing and production methods for M. anisopliae. Colony formation was inhibited by sorbose on a KNO3-based agar medium, but not other carbohydrates. On agar media, sorbose caused abnormal growth and inhibited sporulation by both isolates. All other carbohydrates, but especially soluble starch and mannose, supported growth and sporulation. Oxalic, sorbic, and tartaric acids prevented colony formation. Acetic, citric, and malic acids reduced growth, and acetic and malic acids reduced sporulation. Soy peptone was much better than all simple nitrogen compounds for growth and sporulation. l-glutamine, l-serine, l-asparagine, l-alanine, and KNO3were best for growth, and l-cysteine, l-aspartic acid, NH4NO3, and l-threonine were the worst. (NH4)2SO4, l-lysine, and l-threonine were best for sporulation. Neither isolate sporulated on l-cysteine, l-glutamine, or l-leucine and little or no sporulation occurred on l-alanine and l-serine. Pyridoxine HCl reduced the growth of EF25, and biotin, pyridoxine, and riboflavin reduced sporulation. Pyridoxine HCl reduced the growth of EF55. Various carbohydrates and nitrogen compounds in plant root exudates could cause premature germination in soil, resulting in loss of inoculum. Organic acids might have the opposite effect, contributing to persistence of conidia in soil, but potentially preventing germination on hosts. Soluble starch may be a useful carbon source for use in production media.

Published
1995
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