Water balance,respiration and immobilisation in relation to deltamethrin poisoning and physical conditions in the epigeal spider Oedothorax apicatus     

Gerard A. J. M. Jagers  Op Akkerhuis  Roelof Westerhof  Nico M. Van Straalen  Jan H. Koeman 《Pest management science》1995,44(2):123-130

The effect of a pyrethroid insecticide, deltamethrin, on water loss, metabolic rate and immobilisation was studied, using the epigeal spider Oedothorax apicatus (Blackwall) (Linyphiidae) as a test species. Water loss was measured gravimetrically at different temperatures, air humidities, and doses of deltamethrin. Metabolic rate and immobilisation were measured at different temperatures and doses. Immobilisation was measured at different relative humidities and temperatures. Water loss due to evaporation increased linearly with vapour pressure deficit. The slope of the latter relationship increased with temperature, indicating an increase in cuticle permeability with temperature. In addition to water loss by evaporation, deltamethrin treatment induced water excretion. This was positively related to dose and temperature, but independent of air humidity. Metabolic rate increased with temperature and dose. Immobilisation was highest at low temperatures in combination with low air humidity. The consequences of pesticide-induced water excretion are discussed with respect to field- and laboratory-based dose-effect relationships for pyrethroids presented in the literature. The present results seem to offer an explanation for hitherto unexplained minima in temperature-response curves in pyrethroid toxicity in some arthropod species. It is concluded that simultaneous measurements of metabolic rate, water-loss rate and pesticide effects are a prerequisite for an understanding of the effects of pesticides on arthropods.  相似文献   

Life cycle of the temporary fish parasite, Gnathia africana (Crustacea: Isopoda: Gnathiidae)     

Smi NJ  Basson L  Van As JG 《Folia parasitologica》2003,50(2):135-142

Laboratory work was conducted to elucidate the life cycle of the South African gnathiid isopod, Gnathia africana Barnard, 1914. The natural fish hosts of this temporary parasite, the super klipfish Clinus superciliosus (Linnaeus, 1758), were exposed to gnathiid larvae in the laboratory. It was found that G. africana has three larval stages, consisting of three unfed (zuphea) and three fed (praniza) stages. First-, second- and third-stage zuphea larvae took an average of 2 h 18 min, 2 h 43 min and 10 h 8 min respectively to complete their feeding and the first- and second-stage praniza moulted at 8 and 10 days respectively into the next zuphea stage. Three to six days after its last blood meal, the sex of the third and final praniza stage could be determined by the presence of either a testis or two ovaries in the dorsal pereon. Male larvae moulted into adult males between 8 and 10 days post feeding. Female larvae moulted at approximately 17 days into adult females. Fertilisation of the eggs by the male took place within 24 hours of completion of the female moult. The development of the embryos and subsequent release of the young larvae between 15 and 23 days post fertilisation completed the cycle. This entire cycle took approximately 62 days in water temperatures of 20-25 degrees C.  相似文献   

Linear,logarithmic, and polynomial models of M-mode echocardiographic measurements in dogs     

Gonçalves AC  Orton EC  Boon JA  Salman MD 《American journal of veterinary research》2002,63(7):994-999

OBJECTIVE: To determine whether logarithmic and polynomial models are superior to simple linear models for predicting reference values for M-mode echocardiographic variables in dogs with a wide range of body weights. ANIMALS: 69 apparently healthy adult male and female dogs of various breeds, ages (range, 1 to 12 years; median, 3.5 years), and body weights (range, 3.9 to 977 kg; median, 25.4 kg). PROCEDURE: Echocardiographic M-mode measurements of the interventricular septum, left ventricular dimension (LVD), left ventricular wall, aorta, and left atrium were obtained. Simple linear, second-order polynomial, third-order polynomial, and logarithmic regression models were determined by use of the least-squares method to describe the relationship between M-mode measurements and body weight. Differences in adjusted R2 values of logarithmic and polynomial models were tested for significance of contribution, compared with the simple linear model. RESULTS: Significant differences in adjusted R2 were found when comparing simple linear with logarithmic or polynomial models for LVD-diastole, LVD-systole, aorta, and left atrium. Differences in adjusted R2 between second-order polynomial, third-order polynomial, and logarithmic models were not significant for any M-mode measurement. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, logarithmic or second-order polynomial models predicted reference values of M-mode measurements for size of the cardiac chambers better than simple linear models for dogs with a wide range of body weights. Logarithmic and polynomial models were not superior to simple linear models for M-mode measurements of cardiac wall thickness.  相似文献   

Resistance and susceptibility to Marek's disease: nitric oxide synthase/arginase activity balance     

Djeraba A  Musset E  van Rooijen N  Quéré P 《Veterinary microbiology》2002,86(3):229-244

The metabolic NO pathway, catalyzed by the enzyme NO synthase in macrophages, is a key defense element against viruses and tumors. However, arginase is an other enzyme able to metabolize the substrate L-arginine, and the two enzymes are alternatively regulated by Th1 and Th2 cytokines in murine macrophages. Marek's disease is characterized by strong immunosuppression and development of T-cell lymphomas in chickens. Inoculation of the very virulent strain of MDV RB-1B induced strong and long-lasting arginase macrophage-dependent activity, which was inhibited by L-norvaline in vitro, but induced low NO production in monocytes and splenocytes from highly susceptible B(13)/B(13) chickens. By contrast, in B(21)/B(21) chickens genetically resistant to tumor development, RB-1B induced a weak and transient increase in arginase activity and strong NO production. The vaccinal HVT strain did not induce any arginase activity in monocytes or splenocytes. Moreover, vaccination with HVT prevented tumor appearance after RB-1B challenge and increase in arginase activity, but favored NO production in susceptible chickens. Differential expression of NO synthase and arginase was modulated in chicken macrophages, with IFN-gamma and LPS being strong inducers of both, depending on the type of macrophage, and TGF-beta 1 and PGE(2) stimulating only arginase activity. This increase in arginase activity in macrophages from chickens inoculated with Marek's disease virus might thus be due to a direct effect of the virus on macrophages, possibly through viral products, or to indirect effects on the cytokine balance.  相似文献   

Cross-scale effects of land use on the functional composition of herbivorous insect communities     

Neff  Felix  Blüthgen  Nico  Chisté  Melanie N.  Simons  Nadja K.  Steckel  Juliane  Weisser  Wolfgang W.  Westphal  Catrin  Pellissier  Loïc  Gossner  Martin M. 《Landscape Ecology》2019,34(8):2001-2015

Landscape Ecology - Insect herbivores comprise the majority of macroinvertebrate communities of temperate grasslands and act as drivers for important ecosystem functions. Landscape- and local-level...  相似文献   

Hemoperitoneum secondary to traumatic rupture of an adrenal tumor in a dog     

K Evans  G Hosgood  G D Boon  N Kowalewich 《Journal of the American Veterinary Medical Association》1991,198(2):278-280

Hemoperitoneum secondary to traumatic rupture of an adrenocortical adenocarcinoma was diagnosed in a 10-year-old male dog. Immediate surgical attention was required to remove the tumor and to control hemorrhage. The dog appeared to develop transient hypoadrenocorticism after surgery, but recovered with short-term exogenous corticosteroid administration. At 6 months after surgery, the dog was clinically normal.  相似文献   

Intraerythrocytic merogony in Haemogregarina koppiensis (Apicomplexa: Adeleorina: Haemogregarinidae)     

Smit NJ  Davies AJ 《Folia parasitologica》2005,52(3):277-278

During October 2003, a specimen of Amblyrhynchotes honckenii (Bloch, 1795) was captured at low tide, with a hand net, in a rock pool at Koppie Alleen, De Hoop Nature Reserve, South Africa. This fish was heavily parasitized by unidentified gnathiid praniza larvae, caligid copepods identified as Caligus tetrodontis Barnard, 1948, cymothoid isopods identified as Cinusa tetrodontis (Schioedte et Meinert, 1884), and the blood protozoan Haemogregarina koppiensis Smit et Davies, 2001. Giemsa-stained blood smears from this fish revealed new and unusual stages of merogony for H. koppiensis that included small, rounded, likely intraerythrocytic merozoites arranged in circles of eight around the host nucleus. Host cells appeared ghost-like and enlarged compared with normal erythrocytes. Identical merozoites, usually in clusters of up to 16, were also observed free of host cells. The pattern of merogony seen in H. koppiensis is unusual for a fish haemogregarine.  相似文献   

Assessing the utility of ALOS PALSAR and SPOT 4 to predict timber volumes in even-aged Eucalyptus plantations located in Zululand,South Africa     

Riyad Ismail  Horst Kassier  Morries Chauke  Francesco Holecz  Nico Hattingh 《Southern Forests》2015,77(3):203-211

In commercial forestry, regular terrestrial enumerations of the growing stock are required for the valuation, sustain-able management and planning of current and future timber supplies. In this study we examined whether the combination of synthetic aperture radar (ALOS PALSAR) and optical satellite (SPOT 4) image data can accurately predict the timber volume of even-aged Eucalyptus plantations located in South Africa. Results from this study show that the combination of ALOS PALSAR and SPOT 4 produces a R ² value of 0.68 for the planted model, whereas the coppiced model produced a R ² value of 0.55. However, by including stand age as an independent variable in the stepwise model, there was a 15% improvement for the planted model, whereas the coppiced model produced a 27% improvement. The final model developed in this study produced a R ² value of 0.83 and a RMSE of 31.71?m³ ha?1 for planted stands, whereas the model for coppiced stands produced a R ² value of 0.82 and a RMSE of 27.70?m³ ha?1. As it is not practical or financially feasible for commercial forestry companies to carry out terrestrial enumerations for all plantations on an annual basis, the model developed in this study presents an alternative and accurate method to calculate timber volume for even-aged Eucalyptus plantations.  相似文献   

Intervertebral Disk Disease in 3 Striped Skunks (Mephitis mephitis)     

Maximiljan W. Krauss  Livia Benato  Allison Wack  John J. McDonnell  Nico J. Schoemaker  Ineke Westerhof  Ellen Bronson  Ingrid Gielen  Annemie Van Caelenberg  Tom Hellebuyck  Bjrn P. Meij  Steven De Decker 《Veterinary surgery : VS》2014,43(5):589-592

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Local macrophage proliferation, rather than recruitment from the blood, is a signature of TH2 inflammation     

Jenkins SJ  Ruckerl D  Cook PC  Jones LH  Finkelman FD  van Rooijen N  MacDonald AS  Allen JE 《Science (New York, N.Y.)》2011,332(6035):1284-1288

A defining feature of inflammation is the accumulation of innate immune cells in the tissue that are thought to be recruited from the blood. We reveal that a distinct process exists in which tissue macrophages undergo rapid in situ proliferation in order to increase population density. This inflammatory mechanism occurred during T helper 2 (T(H)2)-related pathologies under the control of the archetypal T(H)2 cytokine interleukin-4 (IL-4) and was a fundamental component of T(H)2 inflammation because exogenous IL-4 was sufficient to drive accumulation of tissue macrophages through self-renewal. Thus, expansion of innate cells necessary for pathogen control or wound repair can occur without recruitment of potentially tissue-destructive inflammatory cells.  相似文献