Factors influencing the occurrence of fall armyworm parasitoids in Zambia     

Durocher-Granger  Léna  Mfune  Tibonge  Musesha  Monde  Lowry  Alyssa  Reynolds  Kathryn  Buddie  Alan  Cafà  Giovanni  Offord  Lisa  Chipabika  Gilson  Dicke  Marcel  Kenis  Marc 《Journal of pest science》2021,94(4):1133-1146

Journal of Pest Science - Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and...  相似文献   

What is your diagnosis? Abnormal cells on a blood smear from a dog     

Julie Lermuzeaux  Marie‐Odile Semin  Catherine Lamour‐Layssol  Marcel Aumann  Catherine Trumel 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2014,43(3):461-462

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Assessing habitat fragmentation on marine epifaunal macroinvertebrate communities: an experimental approach     

Ana Beatriz Pierri-Daunt  Marcel O. Tanaka 《Landscape Ecology》2014,29(1):17-28

Habitat fragmentation is considered a major cause of biodiversity loss, both on terrestrial and marine environments. Understanding the effects of habitat fragmentation on the structure and dynamics of natural communities is extremely important to support management actions for biodiversity conservation. However, the effects of habitat fragmentation on marine communities are still poorly understood. Here we evaluated whether habitat fragmentation affects the structure of epifaunal communities in the sublittoral zone, in the northern coast of São Paulo state, Brazil. Five experimental landscapes were constructed, each one forming a large continuous patch. After 4 weeks, each landscape was cut on three patches of different sizes. Epifaunal macroinvertebrate communities were sampled at the edge and interior of experimental landscapes before manipulation to evaluate edge effects. After four more weeks, communities from the three patch sizes were also sampled to evaluate patch size effects. We compared the diversity of communities at different levels of fragmentation by total abundance, rarefied taxon richness, Shannon–Wiener diversity index, Simpson’s dominance index, and abundance of dominant taxa. Higher taxon richness and gastropod abundance were recorded in the patch edges, but no significant differences were found among patch sizes. We found a significant effect of habitat fragmentation, with lower abundances of Gammaridea (the dominant taxon), Ophyuroidea, and Pycnogonida after the experimental fragmentation. Lower abundances of dominant taxa resulted in higher diversity and lower dominance in fragmented landscapes when compared to integral, pre-manipulation landscapes. Our results suggest that fragmentation of landscapes in the system studied can reduce dominance, and that even small patch sizes can be important for the conservation of macroinvertebrate diversity.  相似文献   

Stimulation of spermiation and induction of ovulation in pike (Esox lucius)     

R. Billard  Jacqueline Marcel 《Aquaculture (Amsterdam, Netherlands)》1980,21(2):181-195

Mature northern pike were given various hormonal treatments in March or April in order to stimulate spermiation or to induce ovulation. In males the total amount of sperm collected after treatment increased, in comparison with saline-injected males, by 3–11 times with partially purified salmon gonadotropin (PPSG-activity: half of the highly purified s-GTH; injected at doses of between 5 and 100 μg/kg body weight); 3–6 times with crude carp pituitary extract (0.5–3 mg/kg body weight); and 3–7 times with fresh pike pituitaries (14 and 1.2 mg wet weight/kg body weight). The sperm obtained after hormonal treatment was of good quality. Intracardiac injection of superactive LRH analogue had no effect. In females, PPSG induced 90 and 100% ovulation at the doses of 50 and 25 μg/kg body weight. Dried salmon pituitaries (2.5 mg/kg, equivalent to 50 μg of PPSG) gave 25% ovulation; at 10 mg/kg, 25% complete ovulation was again recorded, but in addition 70% of the females showed oocyte maturation and partial ovulation. Similarly, dried carp pituitary (3 mg/kg) induced only oocyte maturation but no ovulation. The oocytes obtained after hormonal treatment were in general fertile. Intraperitoneal injection of LRH in an emulsified form induced neither oocyte maturation nor ovulation. The lack of effect of LRH analogue is discussed and shows that the use of this compound as a substitute for pituitary preparation is not very promising.  相似文献   

Performance of soil-applied FeEDDHA isomers in delivering Fe to soybean plants in relation to the moment of application     

Schenkeveld WD  Reichwein AM  Bugter MH  Temminghoff EJ  van Riemsdijk WH 《Journal of agricultural and food chemistry》2010,58(24):12833-12839

FeEDDHA (iron(3+) ethylenediamine-N,N'-bis(hydroxyphenylacetic acid) products are commonly applied to mend and prevent Fe deficiency chlorosis in soil-grown crops. Plants mainly take up Fe in the progressed vegetative and in the reproductive stages. This study examined which of the principal constituents of FeEDDHA products (the isomers racemic o,o-FeEDDHA, meso o,o-FeEDDHA, and o,p-FeEDDHA), most effectively meets the Fe requirements of soybean plants (Glycine max (L.) Merr.) grown on calcareous soil in the aforementioned growth stages. FeEDDHA isomers were applied once, separately or in mixtures, at t = 0, in the progressed vegetative stage or in the reproductive stage. o,p-FeEDDHA did not significantly contribute to Fe uptake in either growth stage. Both racemic and meso o,o-FeEDDHA were effective in supplying plants with Fe, approximately to the same extent. The moment of application had a significant effect on yield and FeEDDHA pore water concentrations at harvest, but not on Fe uptake. To optimize yield while minimizing FeEDDHA dosage, FeEDDHA is best applied to soybean plants prior to the onset of chorosis.  相似文献   

Clinicopathologic features of suspected brevetoxicosis in double-crested cormorants (Phalacrocorax auritus) along the Florida Gulf Coast.     

Christine Kreuder  Jonna A K Mazet  Gregory D Bossart  Tim E Carpenter  Marcel Holyoak  Marc S Elie  Scott D Wright 《Journal of zoo and wildlife medicine》2002,33(1):8-15

Outbreaks of morbidity and mortality in double-crested cormorants (Phalacrocorax auritus) along Florida's Gulf Coast have occurred sporadically for at least 30 yr. During these outbreaks, the Clinic for the Rehabilitation of Wildlife, located on Sanibel Island in Florida, has admitted a substantial number of cormorants with consistent presentation of primarily neurologic clinical signs. In order to investigate the association of these outbreaks in cormorants with exposure to brevetoxin, we compared the timing of admittance of cormorants with outbreak-specific clinical signs to blooms of the brevetoxin-producing marine algae, Karenia brevis (formerly Gymnodinium breve), around Sanibel Island from 1995 through 1999. The clinic admitted 360 out of 613 cormorants with the common clinical sign of severe cerebellar ataxia in six outbreaks occurring during this period. The ataxia was characterized by a broad-based stance, truncal incoordination, hypermetric gait, and intention tremors of the head. The histopathologic findings in 10 cormorants euthanized in 1997 were mild and nonspecific. An immunohistochemical staining technique for the detection of brevetoxin in cormorants documented the uptake of brevetoxin in tissues from four cormorants admitted during an outbreak in 1997, but a modified technique used on samples from 11 cormorants admitted during a K. brevis bloom in 2000 produced indeterminate results. Admittance of cormorants with outbreak-specific clinical signs was positively correlated (P < 0.05) with concurrent concentrations of K. brevis in local water. The cross-correlation coefficient was also significant when increased K. brevis levels preceded cormorant admittances by 2, 4, 6, and 8 wk. This delay in time between K. brevis blooms and cormorant admittance and our clinical finding of neurologic abnormalities in cormorants without overt histopathologic features suggest an association between K. brevis blooms and local cormorant morbidity.  相似文献   

Recovery of native plant communities after the control of a dominant invasive plant species, Foeniculum vulgare: Implications for management     

Jennifer A. Erskine Ogden  Marcel Rejmánek 《Biological conservation》2005,125(4):427-439

The control and/or removal of a dominant invasive species is expected to lead to increases in native species richness and diversity. Small pilot studies were performed on Santa Cruz Island (SCI), California, in the early 1990s to test the efficacy of different methods on the control of Foeniculum vulgare (fennel) and management’s effects on native species recovery. We chose a treatment that showed significant native species recovery, applied it at the landscape scale, and followed its effects on fennel infested plant communities. We tested the hypothesis that results from small-scale studies translate to the landscape level. We found that although the control of fennel translated from the small to landscape scale, decreasing from an average of 60% to less than 3% cover, native species recovery did not occur in the landscape study as it did in the pilot studies. Invasive fennel cover was replaced by non-native grass cover over time. Unexpectedly, fennel cover in untreated fennel plots decreased significantly (though not as drastically) from over 60% cover to just under 40% cover while native species richness in untreated areas increased significantly. The correlation between precipitation and changes in native and non-native species richness and abundance in this study imply that changes in species abundances were highly correlated with environmental fluctuations. The lack of a native seedbank and the accumulation of non-native grass litter likely prevented the recovery of native species in treated areas. Greater vertical complexity found in fennel communities, which increased visitation by frugivorous birds and likely increased native seed dispersal, may have been responsible for the increase in native species richness in the untreated areas. These results suggest that successful invasive species control and native species recovery experiments conducted at small scales may not translate to the landscape level, and active restoration should be an organic component of such large-scale projects.  相似文献   

Triacylglycerol analysis for the quantification of cocoa butter equivalents (CBE) in chocolate: feasibility study and validation     

Dionisi F  Golay PA  Hug B  Baumgartner M  Callier P  Destaillats F 《Journal of agricultural and food chemistry》2004,52(7):1835-1841

A new European legislation (2000/36/CE) has allowed the use of vegetable fats other than cocoa butter (CB) in chocolate up to a maximum value of 5% in the product. The vegetable fats used in chocolate are designated as cocoa butter replacements and are called cocoa butter equivalents (CBE). The feasibility of CBE quantification in chocolate using triacylglycerol (TAG) profiles was conducted by analyzing 55 samples of CBs and 31 samples of CBEs using a liquid chromatograph equipped with an evaporative light scattering detector (HPLC-ELSD). Statistical evaluation of the data obtained has been performed, and a simulation study has been carried out to assess the viability to use this method for quantifying the amount of CBE in real mixtures and in chocolates. The TAGs POP, POS, PLS, and the ratios POP/PLS, POS/PLP (P, palmityl; O, oleyl; S, stearyl; L, linoleyl) are particularly significant to discriminate between CB and CBE. Analysis of 50 mixtures between 5 different CBEs and 10 different CBs at 2 different concentration levels is presented. The data are visualized and interpreted. A mathematical model has been developed to assess the amount of CBE in real mixtures. This predictive model has been successfully applied and validated on dark chocolates including authorized CBE. The results are affected by +/-2.1% absolute average error. In particular, estimations between 10 and 20% of CBE show a very good match. On the other hand, values equal to or smaller than 5% show a larger prediction error (detection limit of the method). For the main purpose of this method (i.e., quantification of CBE at 5% max in chocolate, which represents about 15% of the total fat) this model shows very good results. For milk chocolate, the mathematical model can also be used if TAG are integrated from partition number (PN) 46 to 54. Consequently, the model proposed provides sufficient information to verify the real application of the European legislation.  相似文献   

Lyso-phosphatidylcholine is a signal in the arbuscular mycorrhizal symbiosis     

Drissner D  Kunze G  Callewaert N  Gehrig P  Tamasloukht M  Boller T  Felix G  Amrhein N  Bucher M 《Science (New York, N.Y.)》2007,318(5848):265-268

The arbuscular mycorrhizal (AM) symbiosis represents the most widely distributed mutualistic root symbiosis. We report that root extracts of mycorrhizal plants contain a lipophilic signal capable of inducing the phosphate transporter genes StPT3 and StPT4 of potato (Solanum tuberosum L.), genes that are specifically induced in roots colonized by AM fungi. The same signal caused rapid extracellular alkalinization in suspension-cultured tomato (Solanum lycopersicum L.) cells and induction of the mycorrhiza-specific phosphate transporter gene LePT4 in these cells. The active principle was characterized as the lysolipid lyso-phosphatidylcholine (LPC) via a combination of gene expression studies, alkalinization assays in cell cultures, and chromatographic and mass spectrometric analyses. Our results highlight the importance of lysophospholipids as signals in plants and in particular in the AM symbiosis.  相似文献   

The Lunar Laser Ranging Experiment: Accurate ranges have given a large improvement in the lunar orbit and new selenophysical information     

Bender PL  Currie DG  Poultney SK  Alley CO  Dicke RH  Wilkinson DT  Eckhardt DH  Faller JE  Kaula WM  Mulholland JD  Plotkin HH  Silverberg EC  Williams JG 《Science (New York, N.Y.)》1973,182(4109):229-238

The lunar ranging measurements now being made at the McDonald Observatory have an accuracy of 1 nsec in round-trip travel time. This corresponds to 15 cm in the one-way distance. The use of lasers with pulse-lengths of less than 1 nsec is expected to give an accuracy of 2 to 3 cm in the next few years. A new station is under construction in Hawaii, and additional stations in other countries are either in operation or under development. It is hoped that these stations will form the basis for a worldwide network to determine polar motion and earth rotation on a regular basis, and will assist in providing information about movement of the tectonic plates making up the earth's surface. Several mobile lunar ranging stations with telescopes having diameters of 1.0 m or less could, in the future, greatly extend the information obtainable about motions within and between the tectonic plates. The data obtained so far by the McDonald Observatory have been used to generate a new lunar ephemeris based on direct numerical integration of the equations of motion for the moon and planets. With this ephemeris, the range to the three Apollo retro-reflectors can be fit to an accuracy of 5 m by adjusting the differences in moments of inertia of the moon about its principal axes, the selenocentric coordinates of the reflectors, and the McDonald longitude. The accuracy of fitting the results is limited currently by errors of the order of an arc second in the angular orientation of the moon, as derived from the best available theory of how the moon rotates in response to the torques acting on it. Both a new calculation of the moon's orientation as a function of time based on direct numerical integration of the torque equations and a new analytic theory of the moon's orientation are expected to be available soon, and to improve considerably the accuracy of fitting the data. The accuracy already achieved routinely in lunar laser ranging represents a hundredfold improvement over any previously available knowledge of the distance to points on the lunar surface. Already, extremely complex structure has been observed in the lunar rotation and significant improvement has been achieved in our knowledge of lunar orbit. The selenocentric coordinates of the retroreflectors give improved reference points for use in lunar mapping, and new information on the lunar mass distribution has been obtained. Beyond the applications discussed in this article, however, the history of science shows many cases of previously unknown, phenomena discovered as a consequence of major improvements in the accuracy of measurements. It will be interesting to see whether this once again proves the case as we acquire an extended series of lunar distance observations with decimetric and then centimetric accuracy.  相似文献