First report of the prevalence and genetic characterization of Giardia duodenalis and Cryptosporidium spp. in Yunling cattle in Yunnan Province, southwestern China.

Yunling cattle is an unique cattle breed distributed in Yunnan Province, southwestern China. It is yet to know whether Yunling cattle are infected with Giardia duodenalis and Cryptosporidium spp.. The objectives of the present study were to investigate the prevalence and characterize the assemblages of G. duodenalis and species of Cryptosporidium spp. in Yunling cattle in Yunnan province. The overall prevalence of G. duodenalis and Cryptosporidium spp. were 10.49% (41/391) and 0.77% (3/391), respectively. The age was considered as the risk factor for Yunling cattle infection with G. duodenalis (χ2 = 8.082, OR = 2.56, P = 0.004). Two assemblages of G. duodenalis, assemblage A (n = 1) and assemblage E (n = 40), were identified by amplification of the ß-giardin (bg) and glutamate dehydrogenase (gdh) gene loci using the nested PCR methods. Furthermore, Cryptosporidium andersoni (n = 1) and Cryptosporidium ryanae (n = 2) were detected by nested PCR targeting the small subunit (SSU) rRNA gene. This is the first report of G. duodenalis and Cryptosporidium spp. in Yunling cattle in China, which provided baseline date for further studies of the prevalence, genetic identity, and public health potential of these parasites in Yunling cattle.

Molecular characterization of Eimeria spp. and Blastocystis in rabbits in Shandong Province, China.

Eimeria spp. and Blastocystis are the common parasites that parasitize the intestinal tract of rabbits, which can seriously threaten the health of rabbits and lead to economic losses to the rabbit industry. However, information about the prevalence and transmission of these two parasites in rabbits is limited in China. The objective of this study was to survey the prevalence of Eimeria spp. and Blastocystis in rabbits in Shandong Province. A total of 616 rabbit fecal samples were collected from two cities (Rizhao and Weihai) in Shandong Province, eastern China, and Eimeria spp. and Blastocystis were identified by polymerase chain reaction based on species-specific markers. The prevalence of Eimeria spp. was 20% (123/616) and the Blastocystis prevalence was 0.97% (6/616). Five different Eimeria species (Eimeria intestinalis, E. perforans, E. magna, E. media, and E. irresidua) and the ST4 subtype of Blastocystis were identified in rabbits by sequence analysis. This is the first report of Blastocystis prevalence and subtype ST4 in rabbits in Shandong Province. The findings provide baseline data for the prevention and control of Eimeria spp. and Blastocystis in rabbits in Shandong Province, China.

Distance-dependent quenching and enhancing of electrochemiluminescence from tris(2, 2'-bipyridine) ruthenium (II)/tripropylamine system by gold nanoparticles and its sensing applications.

Understanding the role of gold nanoparticles (AuNPs) in electrochemiluminescence (ECL) processes of the Ru(bpy)32+ (bpy= 2, 2'-bipyridine)/tripropylamine (TPA) system would be beneficial to develop novel ECL sensors for a variety of applications. In this work, we found that the AuNPs on the surface of indium tin oxide (ITO) electrode could catalyze the electrochemical oxidation of TPA, greatly enhancing the ECL signal of Ru(bpy)32+/TPA, present in the solution. If physical separation of AuNPs away from electrode surface after hybridization with target ssDNA, ECL signal decreased dramatically due to the loss of electrochemical activity of AuNPs, based on which a sensitive and specific DNA sensor in a "switch-off" mode was constructed with a detection limit of 0.2 pM. In addition, a suppressing effect of the AuNPs on the ECL of Ru(bpy)32+ was experimentally confirmed by decreasing the electrocatalytic effect to overall ECL emission, including selection of oxalate as a coreactant instead of TPA, or introduction of gold electrode as substrate. Furthermore, when Ru(bpy)32+ and AuNPs were both immobilized on the ITO electrode at close proximity, the ECL quenching induced by energy/electron transfer was predominant. ECL emission of the Ru(bpy)32+/TPA system resulted from a competition between electrocatalytic enhancement and quenching effect. However, the quenched ECL signal would return in case of the AuNPs moving far away from ECL emitters after a hybridization reaction as before, and a separation distance dependent surface enhancement was observed as well. Based on the role change for AuNPs from quenching to enhancing ECL intensity of Ru(bpy)32+/TPA system, a novel ECL DNA sensing strategy in a "turn-on" mode was developed, enabling quantitative analysis of target ssDNA over the range of 0.05 pM to 0.5 nM with a detection limit of 12 fM. Overall, we demonstrated the existence of three effects of AuNPs on the ECL of Ru(bpy)32+/TPA system, and which played the leading role was dependent on the placement of AuNPs, Ru(bpy)32+, and their separation distance. The ECL sensors based on the role change for AuNPs showed both high sensitivity and excellent selectivity.