Colorado Potato Beetle Response to Potato Plants Infected with <Emphasis Type="Italic">Potato Virus Y</Emphasis> and <Emphasis Type="Italic">Potato Leafroll Virus</Emphasis>     

Everett Booth  Andrei Alyokhin 《American Journal of Potato Research》2016,93(3):213-223

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Rearrangement of bacterial community structure during peat diagenesis     

Andrei L. Barkovskii  Hirokazu Fukui  Johannes Leisen  Terence L. Marsh 《Soil biology & biochemistry》2009,41(1):135-143

The relationship between microbial diagenesis of Sphagnum peat (SP) and reed-sedge peat (RSP) and the spatial organization of peat bacterial communities was studied. Peats were aerobically incubated at 18-22 °C for 4 months. Changes in molecular composition of peat organic matter were monitored with solid-state ¹³C NMR, and the respective amount of functional groups was determined by integration of corresponding peaks. No abiotic peat transformation was detected. SP diagenesis caused about a 4% loss of parent materials with a similar yield of ketones, phenols, aromatic, and carbonyl compounds; whereas about 20% of RSP carbohydrates, along with ketones and methoxyl compounds were gradually transformed into carbonyl and aliphatic compounds. SP and RSP substantially varied in bacterial composition. To address spatial community structure, bacterial populations were dissected by a differential elution technique into three fractions based on the degree of their attachment to peat. Community composition was surveyed with T-RFLP (HhaI, MspI, and RsaI). The fragments were further attributed to freely-dispersed (FD), particle-associated (PA), or omnipresent (OMN) bacterial fractions. In both peats, bacterial communities have gradually shifted with the progress of diagenesis. In SP, numbers of exclusively FD or PA bacteria slightly decreased while in RSP their numbers more than doubled after 4-month incubation, and the number of OMN bacteria respectively decreased. The substantially greater changes in the spatial structure of RSP bacterial community compared to SP were consistent with the chemical transformations detected in these peats suggesting the diagenesis-driven divergence of RSP bacterial community into FD and PA sub-communities.  相似文献   

Assessing the Potential of Rhizobacteria to Survive under Phenanthrene Pollution   总被引：1，自引：0，他引：1  

Sergey N. Golubev  Andrei V. Schelud’ko  Anna Yu. Muratova  Oleg E. Makarov  Olga V. Turkovskaya 《Water, air, and soil pollution》2009,198(1-4):5-16

Rhizobacteria possess a wide variety of qualities governing their pollutant-catabolic and rhizospheric competences. We investigated how the abilities to degrade phenanthrene and other polycyclic aromatic hydrocarbons (PAHs), to synthesize surfactants and the phytohormone indole-3-acetic acid (IAA), to be motile, and to perform chemotaxis toward phenanthrene and some potential root-exudate components were manifested in rhizobacteria isolated from oil-polluted sites. We observed that most of the examined rhizobacteria had the abilities under consideration and that in some strains, these were strongly affected by the bacterial environment. Only one strain—Sinorhizobium meliloti P221—exhibited increased PAH-degrading, surfactant-producing, and IAA-synthesizing activities, as well as distinct behavioral responses. We conclude that S. meliloti P221 can be used as a model to assess the contributions of all these activities to plant-inoculation-induced reduction in the soil PAH contents. This strain also may be useful for phytoremediation applications.  相似文献   

Experimental oral transmission of chronic wasting disease to red deer (Cervus elaphus elaphus): Early detection and late stage distribution of protease-resistant prion protein     

Aru Balachandran  Noel P. Harrington  James Algire  Andrei Soutyrine  Terry R. Spraker  Martin Jeffrey  Lorenzo González  Katherine I. O’Rourke 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(2):169-178

Chronic wasting disease (CWD), an important emerging prion disease of cervids, is readily transmitted by intracerebral or oral inoculation from deer-to-deer and elk-to-elk, suggesting the latter is a natural route of exposure. Studies of host range susceptibility to oral infection, particularly of those species found in habitats where CWD currently exists are imperative. This report describes the experimental transmission of CWD to red deer following oral inoculation with infectious CWD material of elk origin. At 18 to 20 months post-inoculation, mild to moderate neurological signs and weight loss were observed and animals were euthanized and tested using 3 conventional immunological assays. The data indicate that red deer are susceptible to oral challenge and that tissues currently used for CWD diagnosis show strong abnormal prion (PrP^CWD) accumulation. Widespread peripheral PrP^CWD deposition involves lymphoreticular tissues, endocrine tissues, and cardiac muscle and suggests a potential source of prion infectivity, a means of horizontal transmission and carrier state.  相似文献   

Cultivating values: environmental values and sense of place as correlates of sustainable agricultural practices     

Noa Kekuewa Lincoln  Nicole M. Ardoin 《Agriculture and Human Values》2016,33(2):389-401

To assess whether and how environmental values and sense of place relate to sustainable farming practices, we conducted a study in South Kona, Hawaii, addressing environmental values, sense of place, and farm sustainability in five categories: environmental health, community engagement and food security, culture and history, education and research, and economics. We found that the sense of place and environmental values indexes showed significant correlation to each category of sustainability in both independent linear regressions and multivariate regression. In total, sense of place explained a larger share of the overall farm performance. However, each indicator showed relative strengths; environmental values showed significantly higher correlation to environmental and educational practices. Furthermore the scales were complimentary, and the use of both scales greatly improved prediction of good farming practices from a multiple-impact perspective. With implications for community and environmental impacts, results suggest that a more comprehensive view of farmers’ environmental values and place connections may help illuminate individual farmers’ decisions and sustainability-related practices.  相似文献   

Introduction to symposium on labor,gender and new sources of agrarian change     

Lincoln Addison  Matthew Schnurr 《Agriculture and Human Values》2016,33(4):961-965

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Andropogon annulatus and Ischaemum rugosom – Two New Weeds of Sugarcane in Trinidad     

Lincoln C. Goberdhan 《国际虫害防治杂志》2013,59(2):178-179

Abstract

Potato cyst-nematode species are believed to have evolved in South America but now have a worldwide distribution and can be major and persistent pests except in the warmest soils. Both species contain pathotypes and their correct identification, although difficult, is important when planning control with resistant potatoes. Some closely related and very similar species are of minor economic importance. Resistant cultivars available at present are effective against only some pathotypes and except where high crop values make use of nematicides economic, it is important to combine extended crop rotation with such cultivars.  相似文献   

Persistence and Profiles of Tetracycline Resistance Genes in Swine Farms and Impact of Operational Practices on Their Occurrence in Farms’ Vicinities   总被引：1，自引：0，他引：1  

Andrei L. Barkovskii  Candace Bridges 《Water, air, and soil pollution》2012,223(1):49-62

Animal farms are recognized as a major contributor to environmental pollution with antibiotic resistance genes, the persistence at the source and the discharge routes to the environment of which need better understanding. The presence of 16 tetracycline resistance genes (TRG) was assessed in feed, feces, manure lagoons, and the vicinities of three Georgia swine farms varied on antibiotic usage and other operational characteristics. In these farms, TRG profiles of feces and lagoons were composed of the same “persistent” and “transient” genes, with the former consistently observed in farms’ proximities and the latter quickly attenuated in the lagoons. Fourteen TRG incidents, 13 of which occurred in gullies, ponds, and creeks, were detected around farms. Their frequency correlated to the cumulative antibiotic usage (R ² = 0.99), number of lagoons (R ² = 0.73), and precipitation (R ² = 0.83), but not to the size of herd or the amount of manure used for fertilization. Gene-specific amplicons of TRG from the farms’ proximities were similar to those of “persistent” TRG from corresponding farms. Our data suggested the independency of TRG profiles of antibiotic usage, variability in TRG persistence in manure lagoons, correlations between operational practices and TRG incidence in farms’ vicinities, and spills and seepage from lagoons as TRG environmental routes.  相似文献   

Investigation of the effects of experimental autolysis on the detection of abnormal prion protein in lymphoid and central nervous system tissues from elk and sheep using the Western blotting method     

Huang H  Soutyrine A  Rendulich J  O'Rourke K  Balachandran A 《Canadian journal of veterinary research》2011,75(1):69-72

Tissues unsuitable for standard immunohistochemical and histopathological examinations for chronic wasting disease (CWD) in cervids and for scrapie in sheep are frequently submitted for testing. This study investigated the effects of experimental autolysis on the detection of abnormal prion protein (PrPsc) in lymphoid and central nervous system (CNS) tissues from elk and sheep. The PrPsc was detected using a Western blotting (WB) test following PrPsc enrichment using sodium phosphotungstic acid (PTA) precipitation (PTA-WB). A commercial enzyme-linked immunosorbent assay (ELISA) was used as a reference test for quantitative measurement. This study showed that the amount of PrPsc in lymphoid and CNS tssues from elk and sheep decreased gradually as a result of autolysis, but PrPsc was still detectable after 5 and 15 d incubation at 37°C by PTA-WB for all lymphoid and CNS samples. The results of the ELISA supported those of PTA-WB, particularly for CNS tissues. In conclusion, autolysis at 37°C for 15 d would not significantly affect the detection of PrPsc in lymphoid and CNS tissues by WB and ELISA and, particularly, PTA-WB is a valuable and alternative confirmatory test to detect PrPsc in autolyzed lymphoid and CNS samples.  相似文献   

Do carbon farming practices build bioavailable nitrogen pools?     

Tuomas J. Mattila  Andrei I. Girz  Mari Pihlatie 《Soil Use and Management》2023,39(4):1532-1544

Agricultural soils contain large amounts of nitrogen (N), but only a small fraction is readily available to plants. Despite several methods developed to estimate the bioavailability of N, there is no consensus on which extraction methods to use, and which N pools are critically important. In this study, we measured six soil N pools from 20 farms, which were part of a multi-year soil carbon sequestration on-farm experiment (Carbon action, 2019–2023). The aim was to quantify the N pools and to evaluate if farming practices that aim to build soil carbon pools, also build bioavailable N pools. We also aimed to test if the smaller and rapidly changing N pools could serve as an indicator for the slower change in soil organic matter. The measured N pools decreased in size, when moving from total N (7700 ± 1500 kg/ha) to slowly cycling (Illinois Soil Nitrogen Test ISNT-N: 1063 ± 220 kg/ha, autoclave citrate-extracted ACE protein N: 633 ± 440 kg/ha), water-soluble organic N (50 ± 17 kg/ha), potentially mineralizable N (33 ± 13 kg/ha) and finally readily plant available inorganic pools (nitrate and ammonium, total: 14 ± 8 kg/ha). In total, the measured pools covered only 18%–44% of total N, indicating a large unidentified N pool, which is either tightly bound to soil mineral fraction and not easily extractable or is bound to undecomposed plant residues and not hydrolysed by the methods. Of the large N pools (ISNT-N, ACE protein and unidentified residual N), clay, carbon (C) and C:Clay ratios explained most of the variability (R² = .90–.93), leaving a minor part of the variation to the management effect. A pairwise comparison of carbon farming and control plots concluded that farming practices had a small (3%–5%) but statistically significant (p < .05) effect on soil total N and ISNT-N pools, and a moderate and significant effect (18%, p < .01) on potentially mineralizable N. The large variation in protein N, water-soluble organic N and inorganic N reduced statistical significance, although individual C sequestration practices had large effects (−30% to +50%). In conclusion, carbon sequestration practices can build both slowly cycling N pools (ISNT) and increase the mineralisation rate of these pools to release plant available forms, resulting in an additional benefit to agriculture through reduced fertilizer application needs.  相似文献