RESUMEN
Cyclospora spp. is a food-borne intestinal protozoan, which is widely distributed in the world and poses the risk of zoonosis. In order to reveal the prevalence of Cyclospora spp. in Holstein cattle in partial areas of the Yunnan Province, 524 fresh fecal samples of Holstein cattle were collected from Dali, Kunming, Chuxiong, and Qujing in Yunnan Province. A nested PCR amplification of the small subunit (SSU) rRNA gene of Cyclospora spp. was carried out, and the products of the nested PCR were further analyzed by restriction fragment length polymorphism (RFLP) using Bsp E â . The results of the present study showed that 13 samples were positive for Cyclospora spp., and the total infection rate of Cyclospora sp. was 2.48%. The infection of Cyclospora spp. was detected in Dali, Qujing, and Chuxiong. Chuxiong showed the highest infection rate (5.71%), and infection rate in Dali and Qujing was 2.19% and 3.16%, respectively. Interestingly, the infection of Cyclospora spp. was not detected in Kunming. The infection of Cyclospora spp. showed no significant differences among different regions (p > 0.05). Cyclospora sp. infection was detected in all ages and sexes, but the differences were not significant (p > 0.05). Sequencing and phylogenetic analysis showed that five Cyclospora spp. samples were closely related to the Cyclospora spp. of humans, and the others were closely related to the Cyclospora spp. of bovines. The results of the present study suggested that there was an infection of Cyclospora spp. in Holstein cattle in the Yunnan Province, and the Cyclospora spp. showed a risk of zoonosis. Thus, the prevention and control of Cyclospora spp. should be strengthened in the Yunnan Province, China. The results of this investigation provide data references for the further research of Cyclosporiasis in Holstein cattle in the Yunnan Province.
RESUMEN
Self-complementary monomer 1, which combines a macrotricyclic polyether and two dibenzylammonium ions together, was synthesized, and its self-assembly into supramolecular polymer networks by host-guest interactions was studied. For the purpose of comparative study, two model molecules 2 and 3 were also prepared. It was found that model molecule 2 and dibenzylammonium ion 4 form a 1:2 complex in solution and in the solid state, which afforded a model system for the investigation of the assembly behavior of monomer 1. Consequently, the (1)H NMR spectrum of 1 in CD(3)CN showed characteristic proton signals similar to the model system, which suggested that 1 self-assembles into a supramolecular polymer network. Formation of the supramolecular polymer was further evidenced by the MALDI-TOF MS spectrum, viscometry, and dynamic light-scattering (DLS) experiments. Moreover, it was found that the decomposition and re-formation of the supramolecular polymer could be chemically controlled by the use of triethylamine and trifluoroacetic acid. Interestingly, the supramolecular polymer forms an organogel both in CD(3)CN and in 1:1 (v/v) CDCl(3)/CD(3)CN, and reversible thermo- and pH-induced gel-sol transitions were also found. The presented work will provide a new strategy for the construction of supramolecular polymers with specific structures and properties.
RESUMEN
On the basis of formation of [2]pseudorotaxane complexes between triptycene-derived tetralactam macrocycles 1a and 1b and squaraine dyes, construction of squaraine-based [2]rotaxanes through clipping reactions were studied in detail. As a result, when two symmetrical squaraines 2d and 2e were utilized as templates, two pairs of isomeric [2]rotaxanes 3a-b and 4a-b as diastereomers were obtained, owing to the two possible linking modes of triptycene derivatives. It was also found, interestingly, that when a nonsymmetrical dye 2g was involved, there existed simultaneously three isomers of [2]rotaxanes in one reaction due to the different directions of the guest threading. The (1)H NMR and 2D NOESY NMR spectra were used to distinguish the isomers, and the yield of [2]rotaxane 5a with the benzyl group in the wider rim of the host 1a was found to be higher than that of another isomer 5b with an opposite direction of the guest, which indicated the partial selection of the threading direction. The X-ray structures of 3b and 4a showed that, except for the standard hydrogen bonds between the amide protons of the hosts and the carbonyl oxygen atoms of the guests, multiple pi...pi stacking and C-H...pi interactions between triptycene subunits and aromatic rings of the guests also participated in the complexation. Crystallographic studies also revealed that the [2]rotaxane molecules 3b and 4a further self-assembled into tubular structures in the solid state with the squaraine dyes inside the channels. In the case of 4a, all the nonsymmetrical macrocyclic molecules pointed in one direction, which suggests the formation of oriented tubular structures. Moreover, it was also found that the squaraines encapsulated in the triptycene-derived macrocycles were protected from chemical attack, and subsequently have potential applications in imaging probes and other biomedical areas.
RESUMEN
A novel anthracene-based cylindrical macrotricyclic polyether containing two dibenzo-30-crown-10 cavities has been synthesized and shown to be a powerful host to form 1:1 stable complexes with the rodlike bispyridinium dications (K(a) > 10(5) M(-1)). Moreover, it was found that the complexes could all self-assemble into linear supramolecular arrays and further 2D mosaic-like architectures in the solid state.
