Monoclonal antibody-based fluorescence polarization immunoassay for sulfamethoxypyridazine and sulfachloropyridazine

In this paper, a new monoclonal antibody (Mab) against sulfamethoxypyridazine (SMP) was produced, and a fluorescence polarization immunoassay (FPIA) based on the produced Mab was developed and optimized for the qualitative screening analysis of SMP. The Mab was raised from mice immunized with SMP linked to bovine serum albumin (BSA) by carbodiimide activated ester formation, using a succinic anhydride spacer molecule between SMP and BSA. Fluorescein labeled sulfachloropyridazine (SCP) and SMP (tracer) were synthesized and purified by thin layer chromatography (TLC). The developed screening FPIA method can tolerate up to 20% methanol, and satisfactory assay sensitivity can be obtained between pH 4 and pH 8 and at lower salt concentration. The anti-SMP Mab exhibited a high cross-reactivity with SCP. The effect of the tracer structure on the analytical characteristic of the determination and on antigen-antibody binding constants was studied. The limits of detection (LOD) were 0.7 ng/mL for SMP and 0.25 ng/mL for SCP in buffer, respectively, whereas negligible cross-reactivities were exhibited by related sulfonamides. Analysis of SMP and SCP-fortified milk samples by the FPIA showed average recoveries from 60 to 145%.     

Effects of slow freezing and vitrification on embryo development in domestic cat

Cryopreservation of gametes and embryos is used to maintain genetic diversity of domestic and wild felids. However, felid oocytes and preimplantation embryos contain large amount of intracellular lipids, which affect their cryosensitivity. The objective was to compare the effects of slow freezing and vitrification and to study lipid phase transition (LPT) during cooling in cat embryos. In vitro-derived embryos were cultured 48 hr up to 4–8 cell stage, thereafter were either slow frozen or vitrified. Propylene glycol (PG) alone was used as a cryoprotective agent (CPA) for slow freezing, and a mixture of PG and dimethyl sulfoxide (DMSO) were used as CPAs for vitrification. After thawing/warming, embryos were in vitro cultured additionally for 72 hr. The total time of in vitro culture was 120 hr for all the groups including non-frozen controls. Effects of both cryopreservation procedures on the subsequent embryo development and nuclear fragmentation rate in embryonic cells were compared. There was no significant differences among the percentages of embryos achieved morula and early blastocyst stage in frozen-thawed group (36.4% and 20.0%), in vitrified-warmed group (34.3% and 28.6%) and in controls (55.6% and 25.9%). Cell numbers as well as nuclear fragmentation rate did not differ in these three groups. Average lipid phase transition (LPT) temperature (T*) was found to be relatively low (–2.2 ± 1.3°C) for the domestic cat embryos. It is supposed that the low LPT of LDs may provide a good background for successful application of slow freezing to domestic cat embryos. Generally, our study indicates that slow freezing and vitrification are both applicable for domestic cat embryo cryopreservation.     

Sperm cryopreservation in the Far‐Eastern wildcat (Prionailurus bengalensis euptilurus)

The Far‐Eastern wildcat (Prionailurus bengalensis euptilurus) is a rare and poorly investigated nondomestic felid species. An attempt of freezing and cryopreserving Far‐Eastern wildcat spermatozoa in CaniPlus Freeze (CPF) medium is reported. Sperm was collected by electroejaculation from five adult Far‐Eastern wildcat captive‐born males. Epididymal spermatozoa from five adult randomly bred domestic cat males were used as a reference. The viability of frozen–thawed spermatozoa evaluated by double staining with SYBR Green I and PI followed by the subsequent confocal laser scanning microscopy (CLSM) was 38.2% ± 3.0% for the domestic cat and 38.0% ± 10.2% for the Far‐Eastern wildcat. The motility of frozen–thawed spermatozoa was 30.8% ± 9.8% for the domestic cat and 33.7% ± 15.1% for the Far‐Eastern wildcat. Sperm morphology was assessed by light microscopy. The total percentage of normal spermatozoa after freezing and thawing was 51.9 ± 5.9 for the domestic cat and 55.0% ± 6.4% for the Far‐Eastern wildcat. Defects of flagella were the most frequently observed abnormalities in both species (32.2% ± 4.8% and 30.8% ± 4.4% of all reported anomalies for the domestic cat and Far‐Eastern wildcat, respectively). Domestic cat epididymal and Far‐Eastern ejaculatory spermatozoa fertilized in vitro‐matured oocytes of the domestic cat (30.0% ± 5.5% and 35.5% ± 15.0%, respectively). Taken together, these results suggest that the freezing of Far‐Eastern wildcat spermatozoa with CPF medium is a suitable method for Felidae cryopreservation.     

固相抗体直接竞争ELISA法测定小白菜和苹果中的甲萘威残留

采用固相抗体直接竞争ELISA法测定小白菜和苹果中的甲萘威残留量 ,并以高效液相色谱法进行验证。结果表明:ELISA法测定小白菜和苹果中甲萘威残留的检测限为0.4 ng/ kg;样本中添加 0.1mg/ kg和 10.0 mg/ kg甲萘威标样 ,以该法测定的回收率分别为80.9%～ 116 %和 86.7%～ 96.3% ,变异系数分别为 9.62 %～ 16.9%和 7.34%～ 11.4 % ;实际样本中甲萘威残留 ELISA测定的变异系数为 6.89%～ 10.3% ,符合残留分析的要求。方法简便快速 ,测定结果与高效液相色谱法测定结果基本一致。     

Diagnostics of the peach root-knot nematode,Meloidogyne floridensis using multiplex real-time PCR

European Journal of Plant Pathology - The peach root-knot nematode, Meloidogyne floridensis is an emerging pest of peach and other crops that is currently known to occur only in California,...     

Bioremediation of Hexachlorocyclohexane-Contaminated Soil by the New <Emphasis Type="Italic">Rhodococcus wratislaviensis</Emphasis> Strain Ch628

Currently, there are large areas of soils contaminated with hexachlorocyclohexane (HCH) isomers which are included in the group of persistent organic pollutants. For the bioremediation of such soils, a new HCH-degrading Rhodococcus wratislaviensis strain Ch628 was isolated from long-term organochlorine contaminated soils. The strain Ch628 was able to degrade 32.3% γ-hexachlorocyclohexane (γ-HCH/lindane), 25.2% hexachlorobenzene, and 100% chlorobenzene in resting cell conditions. The strain Ch628 was bioaugmented in chronically HCH-contaminated soil. The results showed that the bioaugmentation of contaminated soil with the strain Ch628 led to HCH degradation. In the bioaugmented system, the efficiency of HCH removal at the initial concentration of about 238.7 ± 4.9 mg kg^?1 soil was 44.8%, while the system with indigenous microflora (without R. wratislaviensis strain Ch628) and the system with abiotic control removed 33.3 and 16.4% of this compound during the same period, respectively. Strain Ch628 could effectively degrade α-, β-, and γ-isomers of HCH (77.1, 100, and 100%, respectively) and heptachlorocyclohexane (69.9%) in the model soil systems. Moreover, the bioaugmentation with the strain Ch628 led to degradation of tri-, tetra-, and penta-chlorobenzenes, which are of HCH degradation metabolites. For the first time, it was found that the bioaugmentation with the bacterial strain Rhodococcus wratislaviensis Сh628 led to a significant reduction of the toxicity of the HCH-contaminated soil for the test organisms, such as Chlorella vulgaris Beijer and Daphnia magna Straus.     

Land use changes and raptor conservation in steppe habitats of Eastern Kazakhstan

Steppe habitats in central Asia have suffered important land use changes during this century which are similar to those that have been pointed out as the causes of the decline of steppe birds in western Europe. During June 1999 we conducted road surveys of raptors in Eastern Kazakhstan to detect specific and community responses to land use changes. We detected 11 species of raptors. Kestrels (Falco naumanni and tinnunculus) were the most common species in grasslands and agricultural landscapes, harriers (Circus pygargus and macrourus) were dominant in saline steppes and steppe eagles (Aquila nipalensis) were dominant in dry steppes. There were fewer species in agricultural habitats than in grassland and steppe habitats. Ground-nesting raptors were negatively affected by land use changes and four species were never detected in agricultural zones. Raptor abundance patterns differed between natural steppe habitats and human-transformed habitats, where a patchy distribution was detected. The future of raptor communities in Kazakhstan seems uncertain although the progressive abandonment of intensive agriculture may benefit species sensitive to human presence. The long-term conservation of vertebrate communities may depend upon the maintenance of ecologically and socially sustainable grazing systems.     

Variability in Contamination by Heavy Metals: Sampling Implications

The choice of a sampling design forassessing soil contamination is a key issue. The leveland spatial pattern of contaminants needs to be takeninto account by those buying, selling or developingsuch land. This paper evaluates sampling design andsize in order to provide satisfactory and efficientestimates of contamination levels. Geostatisticalmethods are used to quantify the spatial dependence ofheavy metals. Semivariance is calculated forlog-transformed data to minimise the effects ofextreme outliers. Several models at different samplingstages are presented for characterising spatialpattern of heavy metals at the investigated site.Variogram models are calculated for a range of samplesizes. The results are assessed by a jack-knifingtechnique and then used for block kriging. The overallconclusion is that a sample size of 50 to 60 isoptimal for characterising variability incontamination levels at an old industrial site of 6.25 ha.