Development of high-concentration labeled colloidal gold immunochromatographic test strips for detecting african swine fever virus p30 protein antibodies.

African Swine Fever (ASF), caused by the African swine fever virus (ASFV), has inflicted significant economic losses on the pig industry in China. The key to mitigating its impact lies in accurate screening and strict biosecurity measures. In this regard, the development of colloidal gold immunochromatographic test strips (CGITS) has proven to be an effective method for detecting ASFV antibodies. These test strips are based on the ASFV p30 recombinant protein and corresponding monoclonal antibodies. The design of the test strip incorporates a high-concentration colloidal gold-labeled p30 recombinant protein as the detection sensor, utilizing Staphylococcal Protein A (SPA) as the test line (T line), and p30 monoclonal antibody as the control line (C line). The sensitivity and specificity of the test strip were evaluated after optimizing the labeling concentration, pH, and protein dosage. The research findings revealed that the optimal colloidal gold labeling concentration was 0.05 %, the optimal pH was 8.4, and the optimal protein dosage was 10 µg/mL. Under these conditions, the CGITS demonstrated a detection limit of 1:512 dilution of ASFV standard positive serum, without exhibiting cross-reactivity with antibodies against other viral pathogens. Furthermore, the test strips remained stable for up to 20 days when stored at 50 °C and 4 °C. Comparatively, the CGITS outperformed commercial ELISA kits, displaying a sensitivity of 90.9 % and a specificity of 96.2 %. Subsequently, 108 clinical sera were tested to assess its performance. The data showed that the coincidence rate between the CGITS and ELISA was 93.5 %. In conclusion, the rapid colloidal gold test strip provides an efficient and reliable screening tool for on-site clinical detection of ASF in China. Its accuracy, stability, and simplicity make it a valuable asset in combating the spread of ASF and limiting its impact on the pig industry.

[Prevalence and related factors of injury caused by agricultural machinery in the 3 provinces Shandong, Henan and Hebei of China].

OBJECTIVE: To study the prevalent characteristics and related factors of injuries caused by agricultural machinery in 3 provinces Shandong, Henan and Hebei in China. METHODS: A total of 1621 agricultural machinery operators aged between 18 and 60 years old from Shandong, Henan and Hebei provinces were selected by purposive-cluster sampling method in 2009. Demographic characteristics, injury history caused by agricultural machinery in the last year and the related social and psychological factors were collected by self-designed questionnaire. We used statistical description to report the injury prevalence, and adopted the univariate and multivariate analysis to explore the risk factors. RESULTS: The average incidence of injuries caused by agricultural machinery was 13.44% (213/1585) in the three provinces, of which 14.46% (202/1397) in males and 5.85% (11/188) in females (χ(2) = 10.56, P < 0.01). Most of injuries (155 cases, 72.77%) occurred between April and August. Being stuck by rolling starting handles (45 cases, 21.13%), being crushed by running or dropping machineries (32 cases, 15.02%), fall from machines (28 cases, 13.15%) ranked the top three causes of injuries. The main related machines were tractors and motor tricycles (133 cases, 62.44%). The leading types of injuries were scratch (115 cases, 53.99%), strain (68 cases, 31.92%) and fracture (37 cases, 17.37%). RESULTS: of multivariate logistic regression analysis showed that being male (OR = 3.18, 95%CI:1.65-6.15), educational level above high school(OR = 1.69, 95%CI:1.21-2.34), annual family income <2000 yuan (OR = 1.94, 95%CI:1.13-3.32), operating experience ≤ 5 years (OR = 1.70, 95%CI:1.13-2.55), daytime sleepiness (OR = 2.89, 95%CI:1.66-5.01), smoking during machinery operation (OR = 1.43, 95%CI:1.05-1.96), bearing debts (OR = 1.88, 95%CI:1.35-2.63) and suffering from other diseases (OR = 1.42, 95%CI:1.02-1.98) were risk factors of agricultural machinery injuries. CONCLUSION: The average incidence of injuries caused by agricultural machinery in the three provinces Shandong, Henan and Hebei, was rather high among agricultural machinery operators, especially in the males. Agricultural machinery injury has been an important issue endangering the health of rural labor force in recent years.

Laccase-mediator system in the decolorization of different types of recalcitrant dyes.

Phloroglucinol, thymol, and violuric acid (VIO) were selected as laccase mediators after screening 14 different compounds with indigo carmine (indigoid dye) as a substrate. With the presence of these three mediators, a nearly complete decolorization (90-100%) was attained in 1 h. Thus, these three compounds were used as mediators for the decolorization of other four dyes. The results indicated that VIO was effective mediator in decolorization of Remazol brilliant blue R (RBBR, anthraquinoid dye) and Coomassie brilliant blue G-250 (CBB, triphenylmethane dyes), and Acid red (diazo dye). In presence of VIO, the four dyes described above attained 70% decolorization. Thymol was able to mediate decolorization of RBBR and Azure A (heterocyclic dye). Phloroglucinol has no mediating capability in decolorization of the four dyes analyzed. Mediator concentration, pH, and copper ion have an effect on the decolorization of the RBBR. Our data suggested that the decolorization capabilities of laccase/mediator system were related to the types of mediator, the dye structure and decolorization condition.

Molecular evolution of Fome lignosus laccase by ethyl methane sulfonate-based random mutagenesis in vitro.

In order to improve the laccase activity, mutant libraries are constructed through ethyl methane sulfonate-based (EMS) random mutagenesis. Mutagenesis improved expression 3.7-fold to 144 mgl(-1) laccase in yeast, together with a 1.4-fold increase in K(cat). Thus, the total activity is enhanced 5-fold for 2,2'-azino-bis 3-ethylbenzothiaoline-6-sulfonic acid (ABTS). In the presence of 0.6mM copper, the highest activity value reached 30 Uml(-1) after a 3-day cultivation at a temperature of 30 degrees C(.) In comparison with the wild type, the best mutant enzymatic properties (K(m) for ABTS and guaiacol, thermo- and pH stability, optimal pH) are not changed. Moreover, amino acid sequence analysis indicates that there are four substitutions in the best mutant laccase (Gly160Asp, Ala167Thr, Gly174Asp, and Glu234Gly). The best mutant laccase model showed that the Gly160 and Ala167 are to be found near the water channel; especially the distance of Ala167 to the Cu3a is 14.46 A. This implies that it is likely involved in the formation of water channel and that it helps facilitate the easy incoming and outgoing of water.