Sorption and desorption of non-ionic herbicides onto particulate organic matter from surface soils under different land uses

In vegetative filter strips used to intercept pesticides present in run‐off, particulate organic matter derived from the vegetation plays an important function in pesticide sorption processes, because it accumulates at the soil surface and quickly responds to changes in land use. Two herbicides with contrasted properties: isoproturon, moderately hydrophobic (log K_ow= 2.5), diflufenican, strongly hydrophobic (log K_ow= 4.9), and isopropylaniline, a metabolite of isoproturon, were used to characterize the sorption and desorption properties of POM originating from soils under three different land uses: a cropped plot under conventional wheat/maize rotation, an adjacent 10‐year‐old grassed strip and a nearby 80‐year‐old oak/chestnut forest. Chemical structural composition information obtained from solid‐state ¹³C CPMAS NMR and estimation of hydrophobicity from contact angle measurements were used to explain the different sorption capacities of POM according to their size and origins. Sorption of isoproturon and diflufenican increased with hydrophobicity of POM, which was greater in the forest soil. Aromaticity of POM was positively correlated to sorption coefficients (K_oc). Desorption of the more hydrophobic compounds, diflufenican and isopropylaniline was weak for all POM fractions, regardless of their origin and size. On the other hand, desorption of isoproturon depended on land use and POM characteristics. The sorption capacities of POM were not only controlled by their chemical composition, but also by their size, due to a greater number of sorptive sites related to a greater surface area with decreasing particle‐size.     

Development and validation of a specific radioimmunoassay for equine osteocalcin

This study describes for the first time the development and validation of a sensitive and specific radioimmunoassay (RIA) for equine osteocalcin (OC) quantification using purified equine OC as standard, tracer, and immunogen for antibody formation in rabbits. The assay allowed to measure equine serum OC levels with a sensitivity of 0.2 ng/mL. Immunoreactive serum OC values of clinically normal, different-aged horses ranged from 3.68 to 127.31 ng/mL. Intra- and inter-assay coefficients of variation (CV) were 6.2 and 8.2%, respectively. Serial equine serum sample dilutions were linear. The recovery of equine OC from equine serum samples ranged from 93.88 to 107.9%. There was a tight correlation between OC values measured with the equine-specific OC RIA and two commercially available bovine-specific OC RIA kits. However, highest serum OC values were obtained with the equine-specific OC RIA. In conclusion, our equine-specific OC RIA is sensitive, linear, accurate, precise, and reproducible. The assay allowed to quantify OC in equine serum samples and might, therefore, be used to monitor equine osteoblast activity associated with bone diseases, exercise, therapy forms or diet.     

苗期机械拂擦处理对蔬菜植株生长和发育的影响

探明育苗期应用机械拂擦处理代替植物生长延缓剂矮化植株、控制幼苗徒长的可能性。机械拂擦处理强度通过接受处理时间迟早及塑料刷片密度高低来调节。结果表明机械拂擦处理显著延缓植株生长 ,缩短植株节间长度 ,提高茎粗和株高比。甜椒、番茄、黄瓜对机械拂擦处理的敏感性不一 ,生长延缓程度随着处理强度的增加而增加。机械拂擦处理对始花期有一定的影响 ,但对果实产量无不良影响     

Kinetics of four metabolites of febantel in cow's milk

The mammary elimination of four potentially toxic metabolites of Febantel has been investigated by HPLC methods in the cow after the administration of a 7,5 mg/kg single oral experimental dose of this anthelmintic. The total of the four metabolites is equal to about 0.4 ppm 12 hours after the treatment. The individual levels fall down under the detection limit between the third and the sixth milking.     

Pigment composition and location in honey locust (Gleditsia triacanthos) seeds before and after desiccation

Gleditsia triacanthos L. pods were harvested at San Lorenzo del Escorial, Madrid, Spain, before and after seed desiccation. Maturing green pods, harvested from trees, contained soft light-green seeds, whereas fully mature brown pods, collected on the ground, contained hard dark-green seeds. Based on visual inspection of seeds, it was determined that the green color is located in the cotyledons and embryo of soft seeds but mainly in the seed coat of hard seeds. High performance liquid chromatographic analysis indicated that both hard and soft seeds contained the same set of photosynthetic pigments as fully developed leaves, but in different proportions. The hard and soft seeds mainly differed in their chlorophyll a to chlorophyll b ratio and in the composition of the xanthophyll cycle pool of pigments. Fluorescence at -196 degrees C revealed that the molecular organization of the pigment molecules in the seed coat of hard seeds differed from that in intact cotyledons of soft seeds and intact green leaves. The -196 degrees C fluorescence spectra also revealed the presence of a small heterogenous pool of non-photoactive protochlorophyll(ide)s, similar to those found in dark-grown tissues of gymnosperms and angiosperms.     

Involvement of a sodium channel mutation in pyrethroid resistance in Cydia pomonella L, and development of a diagnostic test

Populations of the codling moth, Cydia pomonella L (Lepidoptera, Tortricidae) have developed resistance to several classes of insecticide such as benzoylureas, juvenile hormone analogues, ecdysone agonists and pyrethroids, but the corresponding resistance mechanisms have not been extensively studied. Knockdown resistance (kdr) to pyrethroid insecticides has been associated with point mutations in the para sodium channel gene in a great variety of insect pest species. We have studied two susceptible strains (S and Sv) and two resistant strains (Rt and Rv) of C pomonella that exhibited 4- and 80-fold resistance ratios to deltamethrin, respectively. The region of the voltage-dependent sodium channel gene which includes the position where kdr and super-kdr mutations have been found in Musca domestica L was amplified. The kdr mutation, a leucine-to-phenylalanine replacement at position 1014, was found only in the Rv strain. In contrast, the super-kdr mutation, a methionine-to-threonine replacement at position 918, was not detected in any C pomonella strain. These data allowed us to develop a PCR-based diagnostic test (PASA) to monitor the frequency of the kdr mutation in natural populations of C pomonella in order to define appropriate insecticide treatments in orchards.     

Evaluation of plasma carboxy-terminal cross-linking telopeptide of type I collagen concentration in horses

OBJECTIVE: To evaluate a human assay for quantification of carboxy-terminal cross-linking telopeptide of type I collagen (CTX-I), assess the influence of age on plasma CTX-I concentration, investigate the relationship between plasma CTX-I and serum osteocalcin concentrations, and determine whether concentrations of plasma CTX-I or serum osteocalcin fluctuate in circadian manner in horses. HORSES: 75 clinically normal horses. PROCEDURE: Cross-reactivity between equine serum CTX-I and CTX-I antibodies in an automated electrochemiluminescent sandwich antibody assay (ECLIA) was evaluated via a specificity test (ie, dilution test) and recovery calculation. Serum osteocalcin concentration was measured with an equine-specific osteocalcin radioimmunoassay. To analyze diurnal variations in plasma CTX-I and serum osteocalcin concentrations, blood samples were obtained hourly during a 24-hour period. RESULTS: Results of the dilution test indicated good correlation (r > 0.99) between expected serum CTX-I concentrations and measured serum CTX-I concentrations. The calculated CTX-I recovery was 97.6% to 109.9%. Plasma CTX-I and serum osteocalcin concentrations were correlated. Plasma CTX-I concentration was inversely correlated with age of the horse. No significant circadian variations in plasma CTX-I and serum osteocalcin concentrations were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the fully automated CTX-I ECLIA can be used for evaluation of plasma and serum samples from horses and may be a useful tool to monitor bone metabolism changes. Horses in this study did not have notable diurnal fluctuations in serum osteocalcin and plasma CTX-I concentrations.     

Evaluation of computed tomographic anatomy of the equine metacarpophalangeal joint

OBJECTIVE: To determine the detailed computed tomography (CT) anatomy of the metacarpophalangeal (MCP) joint in healthy horses. SAMPLE POPULATION: 10 cadaveric forelimbs from 10 adult horses without orthopedic disease. PROCEDURES: CT of the MCP joint was performed on 4 forelimbs. In 1 of the limbs, CT was also performed after intra-articular injection of 30 mL of contrast medium (40 mg of iodine/mL). Transverse slices 1-mm thick were obtained, and sagittal and dorsal planes were reformatted with a slice thickness of 2 mm. The CT images were matched with corresponding anatomic slices from 6 additional forelimbs. RESULTS: The third metacarpal bone, proximal sesamoid bones, and proximal phalanx could be clearly visualized. Common digital extensor tendon; accessory digital extensor tendon; lateral digital extensor tendon; superficial digital flexor tendon (including manica flexoria); deep digital flexor tendon; branches of the suspensory ligament (including its attachment); extensor branches of the suspensory ligament; collateral ligaments; straight, oblique, and cruciate distal sesamoidean ligaments; intersesamoidean ligament; annular ligament; and joint capsule could be seen. Collateral sesamoidean ligaments and short distal sesamoidean ligaments could be localized but not at all times clearly identified, whereas the metacarpointersesamoidean ligament could not be identified. The cartilage of the MCP joint could be assessed on the postcontrast sequence. CONCLUSIONS AND CLINICAL RELEVANCE: CT of the equine MCP joint can be of great value when results of radiography and ultrasonography are inconclusive. Images obtained in this study may serve as reference for CT of the equine MCP joint.