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Sigler William V. Reicher Zachary Throssell Clark Bischoff Marianne Turco Ronald F. 《Water, air, and soil pollution》2003,142(1-4):311-326
Microbial degradation of fungicides on leaf surfaces after repeated applications to turfgrass was investigated. Prior andcurrent work in our laboratory has identified two characteristicsof the turfgrass leaf system that may contribute to the enhanceddegradation of fungicides after repeated application to turfgrass:(1) The leaf surface is rich in microorganisms (～108 g-1 dr wt leaf), and (2) Leaf surface microorganisms may respond to repeated fungicide applications in a manner consistentwith the phenomena of enhanced biodegradation. Field studies wereconducted on ‘Penncross' creeping bentgrass with four fungicidesrepresenting three chemical families applied either two or eight times in one growing season. Biodegradation was estimated using data from both a field study and a parallel laboratory study thatfollowed the fate of 14C-labelled fungicides. For the laboratory incubations, the locations of the residual 14C fungicides were estimated using a sequential extraction protocolthat fractionated the materials into three pools: available,retained and bound. Data from both the field and laboratory studyrefuted our hypothesis that enhanced biodegradation would developfollowing repeated applications of the fungicides onto the leafsurface. Our studies support a conclusion that a two-stagephysical sorption process leads to plant incorporation and thiscontrols most of the fungicide's fate. Thus, our data suggestthat microbial activity plays a less important part in theprocess than would be indicated by considering the size of themicrobial population on the leaves. 相似文献
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Agar/galactomannan blends for strawberry (Fragaria x ananassa Duchesne) cv. Pelican micropropagation
The efficacy of partial substitution of agar by galactomannans (GMs) obtained from different sources was tested in strawberry (Fragaria x ananassa Duchesne) cv. Pelican micropropagation. GMs extracted from seeds of Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum – a commercial GM) were mixed with agar in the proportion of 0.3/0.3% (w/v) in MS medium, and the performance was compared with behaviour of medium containing agar only (0.6%, w/v) as gelling agent. The results obtained showed that agar could be partially replaced by GMs, since the rheological measurements confirmed a good interaction between the polysaccharides. Also, better performance and enhanced proliferation of strawberry shoots were observed; where in the modified medium the length of roots was higher. Thus, the behaviour of the agar/galactomannans gels and the commercial cost effectiveness, which is lower for the modified medium compared with the system solidified with agar only, showed the potential use of these galactomannans for application in plant tissue culture. 相似文献
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Polymorphisms in mitochondrial DNA (mtDNA) protein- and tRNA-coding genes were shown to be associated with various diseases in humans as well as with production and reproduction traits in livestock. Alignment of full length mitochondria sequences from the 5 known ovine haplogroups: HA (n = 3), HB (n = 5), HC (n = 3), HD (n = 2), and HE (n = 2; GenBank accession nos. HE577847-50 and 11 published complete ovine mitochondria sequences) revealed sequence variation in 10 out of the 13 protein coding mtDNA sequences. Twenty-six of the 245 variable sites found in the protein coding sequences represent non-synonymous mutations. Sequence variation was observed also in 8 out of the 22 tRNA mtDNA sequences. On the basis of the mtDNA control region and cytochrome b partial sequences along with information on maternal lineages within an Afec-Assaf flock, 1,126 Afec-Assaf ewes were assigned to mitochondrial haplogroups HA, HB, and HC, with frequencies of 0.43, 0.43, and 0.14, respectively. Analysis of birth weight and growth rate records of lamb (n = 1286) and productivity from 4,993 lambing records revealed no association between mitochondrial haplogroup affiliation and female longevity, lambs perinatal survival rate, birth weight, and daily growth rate of lambs up to 150 d that averaged 1,664 d, 88.3%, 4.5 kg, and 320 g/d, respectively. However, significant (P < 0.0001) differences among the haplogroups were found for prolificacy of ewes, with prolificacies (mean ± SE) of 2.14 ± 0.04, 2.25 ± 0.04, and 2.30 ± 0.06 lamb born/ewe lambing for the HA, HB, and the HC haplogroups, respectively. Our results highlight the ovine mitogenome genetic variation in protein- and tRNA coding genes and suggest that sequence variation in ovine mtDNA is associated with variation in ewe prolificacy. 相似文献
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V. Acosta-Martínez Z. Reicher M. Bischoff R. F. Turco 《Biology and Fertility of Soils》1999,29(1):55-61
The influence of tree leaf amendment and N fertilization on soil quality in turfgrass environments was evaluated. Our objective
was to assess changes in soil quality after additions of leaf materials and N fertilization by monitoring soil chemical and
physical parameters, microbial biomass and soil enzymes. Established perennial ryegrass (Lolium perenne) plots were amended annually with maple (Acer spp.) leaves at three different rates (0, 2240, and 4480 kg ha–1 year–1) and treated with three nitrogen rates (0, 63, and 126 kg N ha–1 year–1). Tree leaf mulching did not significantly affect water infiltration or bulk density. However, trends in the data suggest
increased infiltration with increasing leaf application rate. Tree leaf mulching increased total soil C and N at 0–1.3 cm
depth but not at 1.3–9.0 cm. Extracted microbial phospholipid, an indicator of microbial biomass size, ranged from 28 to 68
nmol phospholipid g–1 soil at the 1.3–9.0 cm depth. The activity of β-glucosidase estimated on samples from 0–1.3 cm and 1.3–9.0 cm depths, and
dehydrogenase activity estimated on samples from 1.3–9.0 cm were significantly increased by leaf mulching and N fertilizer
application. Changes in microbial community composition, as indicated by phospholipid fatty acid methyl ester analysis, appear
to be due to seasonal variations and did not reflect changes due to N or leaf amendment treatments. There were no negative
effects of tree leaf mulching into turfgrass and early data suggest this practice will improve soil chemical, physical, and
biological structure.
Received: 10 December 1997 相似文献
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Reicher S Ramos-Nieves JM Hileman SM Boisclair YR Gootwine E Gertler A 《Journal of animal science》2012,90(2):410-418
Leptin (LEP) is a cytokine-like hormone proven to be involved in diverse biological processes. In livestock, it regulates feed intake, BW homeostasis, and energy balance, among other traits. Natural nonsynonymous genetic polymorphisms in the ovine leptin (oLEP) alter the biochemical and physiological characteristics of its gene products. Here we studied in vitro and in vivo the biochemical and physiological characteristics of recombinant hormones representing the oLEP and bovine leptin (bLEP) reference sequences of wild-type (WT) leptins (GenBank accession No. U84247 and U50365, respectively), oLEP and bLEP recombinant muteins carrying the R4C mutation, and oLEP recombinant hormones carrying the A59V and Q62R mutations, which were detected in bLEP. All proteins were purified to homogeneity as monomers and formed 1:1 molar ratio complexes with the chicken leptin-binding domain (LBD). Surface plasmon resonance experiments revealed that all protein variants exhibit reduced (P < 0.05) affinity to chicken (ch) and human (h) LBD compared with the WT oLEP and bLEP recombinant proteins. The ovine and bovine R4C muteins exhibited significantly (P < 0.05) greater induction of cell proliferation in a Baf/3 cell line bioassay, despite lower affinity toward both hLBD and chLBD. Intra-third cerebral ventricle infusion of oLEP and its 3 muteins in sheep resulted in reduced feed intake. However, the 3 tested muteins had a decreased (P < 0.05) inhibitory effect than the WT LEP. It was concluded that natural genetic polymorphisms in the bLEP are associated with variation in the biochemical and physiological properties of the protein. 相似文献
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R Reicher 《Tier?rztliche Praxis》1985,13(3):291-294
Observations on the clinic showed a high frequency (round 20%) of toes in cattle, damaged by non-professional claw-trimming. Various types of mistakes are shown by examples and the severity of the subsequent diseases is emphasized. Increased instruction of qualified persons for the care of the claw could relief the problems. 相似文献
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