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951.
Jenita Thinakaran David R. Horton W. Rodney Cooper Andrew S. Jensen Carrie H. Wohleb Jennifer Dahan Tariq Mustafa Alexander V. Karasev Joseph E. Munyaneza 《American Journal of Potato Research》2017,94(5):490-499
Potato psyllid, Bactericera cockerelli (?ulc), causes economic damage to potato crops throughout the major potato growing regions of western North America. When cultivated crops are not available, potato psyllid often occurs on non-crop hosts. In the southern U.S. and northern Mexico, native species of Lycium (Solanaceae) are important non-crop hosts for the psyllid. We determined whether Old World species of Lycium now widespread in the Pacific Northwest are reservoirs of potato psyllid in this growing region. We examined Lycium spp. across a wide geographic region in Washington, Oregon, and Idaho at irregular intervals during three growing seasons. Potato psyllids were present at all locations. To determine whether Lycium is also a host during intervals of the year in which the potato crop is not available, we monitored a subset of these sites over the entire year. Six sites were monitored at 1- to 3-week intervals from June 2014 to June 2016. Psyllids were present on Lycium throughout the year at all sites, including during winter, indicating that Lycium is also a host when the potato crop is seasonally not available. Psyllid populations included a mixture of Northwestern and Western haplotypes. We observed well-defined spring and fall peaks in adult numbers, with peaks separated by long intervals in which psyllid numbers were very low. Seasonal patterns in psyllid numbers on these non-native Lycium hosts were very similar to what has been observed on native Lycium in the desert southwest region of the U.S. Our findings demonstrate that potato psyllid associates with Lycium across a broad geographic region within the Pacific Northwest. These results will assist in predicting sources of potato psyllid colonizing potatoes in this important growing region. 相似文献
952.
Joanna Sousa Vasconcelos Franco António ChaveiroAna Góis BSc Fernando Moreira da Silva PhD 《Journal of Equine Veterinary Science》2013
This study investigated the effects of ascorbic acid and α-tocopherol supplementation on semen quality parameters of equine thawed-frozen semen. Semen was divided in seven different treatments in a final concentration of 100 × 106 sperm/mL by using Gent extender containing no supplements (control) and the following supplements with three different concentrations: α-tocopherol (0.5, 1, and 2 mM) and ascorbic acid (0.45, 0.9, and 1.8 g/L). After thawing, all samples were maintained at 37°C, while analyses were performed at 0, 60, and 120 minutes. Evaluation of viability and acrosome status (using Pisum sativum agglutinin conjugated to fluorescein isothiocyanate and propidium iodide), mitochondrial membrane potential (5,5′,6,6′-tetrachloro-1,1′,3,3′tetraethylbenzimidazolyl carbocyanine iodine [JC-1]), membrane lipid peroxidation (LPO; C11-BODIPY581/591), and stability of the plasmatic membrane (merocyanine 540 and Yo-Pro-1) of each sample was determined by flow cytometry. Relative to the control group, supplementation with α-tocopherol improved (P ≤ .05) postthaw membrane LPO, yet the higher concentrations of ascorbic acid (0.9 and 1.8 g/L, respectively) showed a negative effect on membrane LPO. Neither antioxidant significantly increased (P > .05) the acrosome integrity and mitochondrial membrane potential of frozen-thawed spermatozoa, although supplementation with α-tocopherol and ascorbic acid (0.9 and 1.8 g/L, respectively) had a positive effect on membrane integrity and stability (P ≤ .05). For all semen parameters, the lower concentration of ascorbic acid (0.45 g/L) did not show significant differences (P > .05) compared with the control. In conclusion, α-tocopherol seems to be an efficient antioxidant for reducing the oxidative stress provoked by cryopreservation, decreasing lipid peroxidation on equine spermatozoa. 相似文献
953.
954.
This paper focuses on examining the dynamic nature of community supported agriculture (CSA) and the real-world experiences
which mark its contours, often making it distinct from the early idealized CSA “model.” Specifically, our study examines the
narratives of the farmers of Devon Acres CSA over its duration, in tandem with a survey of recent shareholders in order to
understand and explain its evolution. The framework we develop here shows that this CSA is largely characterized by instrumental and functional beliefs and practices, with some elements in the collaborative mode. A key contribution of this research is the development of a framework which helps to highlight the relative fluidity
and patchwork quality of CSA participant positions over time. At Devon Acres, the real-world factors and issues influencing
CSA evolution are seen to be products of both the local and larger contexts, evident in such areas as shifts in farmer learning
and adaptation, differences between beliefs and practices in member volunteer efforts, and changes in farm and resource conditions.
With respect to CSA more broadly, we argue that the reality of dominant food system context and site-specific influences on
CSA development compels us to rework our attachment to early idealized “model” traits. Expansion in CSA numbers, evidence
of adaptation and situated learning, and retention of the local and organic as core traits, speak to the pragmatic yet transformative potential of CSA contribution to food system change.
Robert Feagan PhD, is a faculty member in the interdisciplinary Contemporary Studies Program at the Brantford Campus of Wilfrid Laurier University in Ontario, Canada. His research and teaching interests are in local and regional food systems—farmers’ markets, CSAs, etc., in university–community partnerships, in community development, and in the green-burial movement. Ideas and objectives of “sustainability” underlie his many research directions. Amanda Henderson earned a Masters Degree from the Faculty of Environmental Studies at York University in Toronto. She lives and works on a communal eco-farm in rural Ontario, Canada. 相似文献
Robert FeaganEmail: |
Robert Feagan PhD, is a faculty member in the interdisciplinary Contemporary Studies Program at the Brantford Campus of Wilfrid Laurier University in Ontario, Canada. His research and teaching interests are in local and regional food systems—farmers’ markets, CSAs, etc., in university–community partnerships, in community development, and in the green-burial movement. Ideas and objectives of “sustainability” underlie his many research directions. Amanda Henderson earned a Masters Degree from the Faculty of Environmental Studies at York University in Toronto. She lives and works on a communal eco-farm in rural Ontario, Canada. 相似文献
955.
Wang Bao Gong Hong Tao Li Shou Qi Xie Jia Shou Liu Brian R. Murphy Song Guang Xie 《Fisheries Science》2009,75(5):1157-1165
Neosalanx taihuensis were sampled from the Tian-e-zhou Oxbow from March 2006 through November 2007. Two separate spawning seasons were identified
based on the annual reproductive cycles of the females, designated as the autumn-spawning season and the spring-spawning season.
Lifespan of the offspring of the spring-spawning fish was 1 year, with them dying after the subsequent spring spawning. Autumn-spawned
females seem to be the offspring of the spring-spawning fish, based on monthly changes in the length–frequency distributions.
Spring-mature females had higher absolute fecundity, gonadosomatic index, and relative condition factor in 2007 than in 2006.
Relative condition factor of the immature female offspring of spring-spawning fish was higher in 2007 than in 2006, portending
a further increase in reproductive investment during the spring spawning of 2008. The increasing reproductive investment suggests
that the population of N. taihuensis in the Tian-e-zhou Oxbow may be recovering from its recent decline. 相似文献
956.
Motoaki Tojo Ken Watanabe Kenichi Kida Yingjie Li Shuhei Numata 《Journal of General Plant Pathology》2007,73(2):121-124
Severe mottle necrosis (Shirogusare-byo in Japanese) was found on mature tubers of sweet potato (Ipomoea batatas) in Ibaraki Prefecture in October 2004. The causal organism was identified as Pythium scleroteichum hitherto unknown in Japan. Sweet potato cultivar Purple Sweet Lord was more susceptible than cultivars Beniazuma, Benimasari,
Koukei-14, and Tamayutaka to the pathogen at 25°C, while this difference in the susceptibility was not clear at 15°C. 相似文献
957.
Ahmed Ibrahem I. Badawy Kathleen Lutz Anja Taubert Horst Zahner Carlos Hermosilla 《Veterinary research communications》2010,34(2):103-118
Host immune responses conducted against antigens of Eimeria bovis are key factors for the development of protective immunity against this protozoan disease. In this study we investigated
the expression of E. bovis-derived antigens on the host cell surface membrane during E. bovis first merogony in vitro. Host cells carrying E. bovis-meront I stages expressed E. bovis host cell surface antigens (EbHCSAg) on their surface membrane which were recognised by hyperimmune sera of calves and by
sera from rats immunized with E. bovis merozoites I, when tested by indirect immune fluorescent antibody test (IIFAT), laser scanning confocal microscopy (LSCM)
and immune electron microscopy. Expression of EbHCSAg on permissive host cells was earliest detected 7 days p. i., thus coinciding
with the onset of the parasite replication. Membrane-associated EbHCSAg were removed from infected host cells by proteinase
K, partially by Triton X-100, Triton X-114 and Triton X-405, but not by 1 M NaCl, CHAPS or phospholipase C treatment. Antibodies,
affinity-purified on paraformaldehyde/glutardialdehyde (PAGA)-fixed E. bovis meront I-infected bovine host cells bound to the surface meront I-carrying cells and to merozoites I (IIFAT, LSCM) but, in
contrast to untreated sera, not to sporozoites. When tested on methanol-fixed merozoites I and sporozoites by IIFAT, affinity-purified
antibodies bound to structures in the apical complex area of merozoites I, but not to sporozoites, whilst untreated sera caused
diffuse labelling of internal structures of both parasite stages. Immune electron microscopy demonstrated binding of affinity-purified
antibodies to micronemes and dense granules of merozoites I. Although the function of EbHCSAg is still unknown, results of
this study might suggest an involvement in the development of protective immunity against E. bovis infections. 相似文献
958.
Juliana DF Barbosa Viviane B Silva Péricles B Alves Giuseppe Gumina Roseli LC Santos Damião P Sousa Sócrates CH Cavalcanti 《Pest management science》2012,68(11):1478-1483
BACKGROUND: Dengue fever is a severe public health problem for several countries. In order to find effective larvicides to aid control programs, the structure‐activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae were evaluated. Additionally, the composition and larvicidal activity of Syzygium aromaticum essential oil was assessed. RESULTS: Four compounds representing 99.05% of S. aromaticum essential oil have been identified. The essential oil was active against Ae. aegypti larvae (LC50 = 62.3 and 77.0 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity of eugenol, the major compound of the essential oil, was further evaluated (LC50 = 93.3 and 71.9 ppm, field‐collected and Rockefeller larvae respectively). The larvicidal activity and structure‐activity relationships of synthetic derivatives of eugenol were also assessed. The larvicidal activity of the derivatives varied between 62.3 and 1614.9 ppm. Oxidation of eugenol allylic bond to a primary alcohol and removal of the phenolic proton resulted in decreased potency. However, oxidation of the same double bond in 1‐benzoate‐2‐methoxy‐4‐(2‐propen‐1‐yl)‐phenol resulted in increased potency. CONCLUSION: Structural characteristics were identified that may contribute to the understanding of the larvicidal activity of phenylpropanoids. The present approach may help future work in the search for larvicidal compounds. Copyright © 2012 Society of Chemical Industry 相似文献
959.
A carbonaceous sorbent was prepared from the wood of Japanese larch (Larix leptolepis) by dehydration with concentrated sulfuric acid in a 69% yield. The abilities of the sorbent to remove Cr(VI) from aqueous
solutions were investigated. Research parameters included the initial solution pH, temperature, and initial concentration
of Cr(VI) in solution. The removal of Cr(VI) was highly solution pH dependent and was mainly governed by physicochemical sorption
under weak acidic conditions. The equilibrium data fit well in the Langmuir isotherm model. The Langmuir constants were calculated
at different temperatures, and the sorption capacity increased with rising temperature, indicating the endothermic nature
of the Cr(VI) sorption onto the sorbent. The desorption experiments suggest that the Cr(VI) sorption is generally irreversible,
owing to strong interaction of HCrO
4
−
with the active sites of the sorbent. 相似文献
960.
Mélanie Saulnier Jean-Louis Edouard Christophe Corona Frédéric Guibal 《Annals of Forest Science》2011,68(1):189-200