The golden snub-nosed monkey (Rhinopithecus roxellana) is an endangered species endemic to China. Relatively little is known about the taxonomic status of soil-transmitted helminths (STH) in these monkeys. Trichuris spp. (syn. Trichocephalus) are among the most important STHs, causing significant socio-economic losses and public health concerns. To date, five Trichuris species have been reported in golden monkeys, including a novel species, T. rhinopiptheroxella, based on morphology. In the present study, molecular and morphological analysis was conducted on adult Trichuris worms obtained from a dead golden snub-nosed monkey, to better understand their taxonomic status. Morphology indicated that the adult Trichuris worms were similar to T. rhinopiptheroxella. To further ascertain their phylogenetic position, the complete mitochondrial (mt) genome of these worms was sequenced and characterized. The mt genome of T. rhinopiptheroxella is 14,186 bp, encoding 37 genes. Phylogenetic analysis based on the concatenated amino acids of 12 protein-coding genes (with the exception of atp8) indicated that T. rhinopiptheroxella was genetically distinct and exhibited 27.5–27.8% genetic distance between T. rhinopiptheroxella and other Trichuris spp. Our results support T. rhinopiptheroxella as a valid Trichuris species and suggest that mt DNA could serve as a marker for future studies on the classification, evolution and molecular epidemiology of Trichuris spp. from golden snub-nosed monkeys.

Pseudanoplocephala crawfordi is an important zoonotic cestode of economic significance and public health concern. In spite of its significance as a pathogen, the systematics, genetics, epidemiology and biology of this parasite remain poorly understood. In the present study, we sequenced and characterized the complete mitochondrial (mt) genome of P. crawfordi, which is 14,192 bp long and encodes 36 genes, including 12 protein-coding genes, 22 transfer RNA genes and two ribosomal RNA genes. Phylogenetic analysis of the concatenated amino acid sequences using the Bayesian inference (BI) method showed that P. crawfordi was closely related to the family Hymenolepididae. Considering that the taxonomic status of P. crawfordi has been controversial when based only on morphological features, the mt genome obtained here will provide novel molecular markers to ascertain the phylogenetic position of this parasite accurately.

Internal transcribed spacer (ITS) rDNA sequences of three Nematodirus species from naturally infected goats or sheep in two endemic provinces of China were analysed to establish an effective molecular approach to differentiate Nematodirus species in small ruminants. The respective intra-specific genetic variations in ITS1 and ITS2 rDNA regions were 0.3–1.8% and 0–0.4% in N. spathiger, 0–6.5% and 0–5.4% in N. helvetianus, and 0–4.4% and 0–6.1% in N. oiratianus from China. The respective intra-specific variations of ITS1 and ITS2 were 1.8–4.4% and 1.6–6.1% between N. oiratianus isolates from China and Iran, 5.7–7.1% and 6.3–8.3% between N. helvetianus samples from China and America. For N. spathiger, compared with samples from China, sequence differences in ITS1 rDNA were 0.3–2.4% in isolates from America, 0.3–2.9% in New Zealand and 2.1–2.4% in Australia. Genetic variations in ITS2 rDNA of N. spathiger were 0–0.4% between samples from China and America, and 0–0.8% between samples from China and New Zealand. Using mutation sites, polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) and specific PCR techniques were developed to differentiate these three Nematodirus species. The specific PCR assay allowed the accurate identification of N. oiratianus from other common nematodes with a sensitivity of 0.69 pg and further examination of Nematodirus samples demonstrated the reliability of these two molecular methods.

Trichuris trichiura and Trichuris suis parasitize (at the adult stage) the caeca of humans and pigs, respectively, causing trichuriasis. Despite these parasites being of human and animal health significance, causing considerable socio-economic losses globally, little is known of the molecular characteristics of T. trichiura and T. suis from China. In the present study, the entire first and second internal transcribed spacer (ITS-1 and ITS-2) regions of nuclear ribosomal DNA (rDNA) of T. trichiura and T. suis from China were amplified by polymerase chain reaction (PCR), the representative amplicons were cloned and sequenced, and sequence variation in the ITS rDNA was examined. The ITS rDNA sequences for the T. trichiura and T. suis samples were 1222–1267 bp and 1339–1353 bp in length, respectively. Sequence analysis revealed that the ITS-1, 5.8S and ITS-2 rDNAs of both whipworms were 600–627 bp and 655–661 bp, 154 bp, and 468–486 bp and 530–538 bp in size, respectively. Sequence variation in ITS rDNA within and among T. trichiura and T. suis was examined. Excluding nucleotide variations in the simple sequence repeats, the intra-species sequence variation in the ITS-1 was 0.2–1.7% within T. trichiura, and 0–1.5% within T. suis. For ITS-2 rDNA, the intra-species sequence variation was 0–1.3% within T. trichiura and 0.2–1.7% within T. suis. The inter-species sequence differences between the two whipworms were 60.7–65.3% for ITS-1 and 59.3–61.5% for ITS-2. These results demonstrated that the ITS rDNA sequences provide additional genetic markers for the characterization and differentiation of the two whipworms. These data should be useful for studying the epidemiology and population genetics of T. trichiura and T. suis, as well as for the diagnosis of trichuriasis in humans and pigs.

The present study examined sequence variation in three mitochondrial DNA (mtDNA) genes, namely cytochrome c oxidase subunit 3 (cox3) and NADH dehydrogenase subunits 1 and 4 (nad1 and nad4), among Ascaridia galli isolates from different geographical localities in China. A portion of cox3 (pcox3), nad1 (pnad1) and nad4 (pnad4) genes were amplified by polymerase chain reaction (PCR) separately from adult A. galli individuals and the amplicons were subjected to sequencing from both directions. The length of the sequences of pcox3, pnad1 and pnad4 were 408 bp, 471 bp and 333 bp, respectively. The intraspecific sequence variations within A. galli were 0–1.7% for pcox3, 0–2.8% for pnad1 and 0–3.4% for pnad4. The A+T contents of the sequences were 67.16–67.65% (pcox3), 67.09–67.94% (pnad1) and 69.91–71.77% (pnad4). The interspecific sequence differences among members of the Ascaridida were significantly higher, being 13.2–30.9%, 12.8–29.0% and 15.1–34.1% for pcox3, pnad1 and pnad4, respectively. Phylogenetic analyses using combined sequences of pcox3, pnad1 and pnad4, with three different computational algorithms (Bayesian analysis, maximum likelihood and maximum parsimony), all revealed distinct groups with high statistical support. These findings demonstrated the existence of intraspecific variation in mitochondrial DNA (mtDNA) sequences among A. galli isolates from different geographical regions in China, and have implications for studying molecular epidemiology and population genetics of A. galli.

The present study examined sequence variation in four mitochondrial (mt) genes, namely cytochrome c oxidase subunits 1 (cox1) and 2 (cox2), and NADH dehydrogenase subunits 1 and 2 (nad1 and nad2) among Clonorchis sinensis isolates from different endemic regions in China, and their phylogenetic relationships with other zoonotic trematodes were reconstructed. A portion of the cox1 and cox2 genes (pcox1 and pcox2), and nad1 and nad2 genes (pnad1 and pnad2) were amplified separately from individual liver flukes by polymerase chain reaction (PCR) and the amplicons were subjected to sequencing from both directions. The intra-specific sequence variations within C. sinensis were 0–1.6% for pcox1, 0–1.4% for pcox2, 0–0.9% for pnad1 and 0–1.0% for pnad2. Phylogenetic analyses based on the combined sequences of pcox1, pcox2, pnad1 and pnad2 revealed that all the C. sinensis isolates grouped together and were closely related to Opisthorchis felineus. These findings revealed the existence of intra-specific variation in mitochondrial DNA (mtDNA) sequences among C. sinensis isolates from different geographic regions, and demonstrated that mtDNA sequences provide reliable genetic markers for phylogenetic studies of zoonotic trematodes.

Sequence variability in three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 3 (cox3), NADH dehydrogenase subunits 1 and 4 (nad1 and nad4) in Spirometra erinaceieuropaei spargana from different geographical regions in China was examined. A portion of each of the cox3 (pcox3), nad1 (pnad1) and nad4 genes (pnad4) were amplified separately from individual S. erinaceieuropaei spargana by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. The sequences of pcox3, pnad1 and pnad4 were 541, 607 and 847 bp in length, respectively. The A+T contents of the sequences were 68.39–68.76% (pcox3), 63.76–64.91% (pnad1) and 67.18–67.77% (pnad4), respectively, while the intra-specific sequence variations within each of the S. erinaceieuropaei spargana were 0–1.5% for pcox3, 0–2.8% for pnad1 and 0–2.7% for pnad4. Phylogenetic analysis using neighbour joining (NJ), maximum likelihood (ML) and maximum parsimony (MP) methods, indicated that all the spargana isolates in Hunan Province represented S. erinaceieuropaei. These findings demonstrated clearly the usefulness of the three mtDNA sequences for population genetics studies of S. erinaceieuropaei spargana of human and animal health significance.

Sequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 4 (nad4), and internal transcribed spacer (ITS) of rDNA among and within three cestodes, Spirometra erinaceieuropaei, Taenia multiceps and Taenia hydatigena, from different geographical origins in China was examined. A portion of the cox1 (pcox1), nad4 genes (pnad4) and the ITS (ITS1+5.8S rDNA+ITS2) were amplified separately from individual cestodes by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. While the intra-specific sequence variations within each of the tapeworm species were 0–0.7% for pcox1, 0–1.7% for pnad4 and 0.1–3.6% for ITS, the inter-specific sequence differences were significantly higher, being 12.1–17.6%, 18.7–26.2% and 31–75.5% for pcox1, pnad4 and ITS, respectively. Phylogenetic analyses based on the pcox1 sequence data revealed that T. multiceps and T. hydatigena were more closely related to the other members of the Taenia genus, and S. erinaceieuropaei was more closely related to the other members of the Spirometra genus. These findings demonstrated clearly the usefulness of mtDNA and rDNA sequences for population genetic studies of these cestodes of socio-economic importance.

Gallium nitride (GaN) has been synthesized by reacting gallium trichloride with ammonia (NH3) at low temperatures ranging from 500 to 1000 °C for 12 h. X-ray diffraction, transmission electron microscopy, infrared, and Raman backscattering spectra revealed that the synthesized GaN powder consists of single-phase nano-sized crystallites with the wurtzite-type structure. The average size of the crystals decreases with the reaction temperature from approximately ∼63 nm at 1000 °C to ∼5 nm at 500 °C. GaOCl and ϵ–Ga2O3 are the intermediate products during synthesis of the GaN. Characteristic shifts of the Raman peaks are associated with the change in crystal size. The band-edge emission of GaN at 361 nm was observed on room temperature photoluminescence spectra exclusively for the sample synthesized at 1000 °C, while a new and broad emission band appeared with the center ranging from 827 to 765 nm for the samples synthesized between 500 and 800 °C.

We have performed photoluminescence (PL) measurements at liquid nitrogen temperature under high pressure up to 5.5 GPa and in the temperature range 10-300 K at atmospheric pressure on {(ZnSe)30(ZnSe0.92Te0.08)30(ZnSe)30[(CdSe)1(ZnSe)2]9}x5 multiple quantum wells. The PL peaks, EB, E1 and Ew corresponding to the band edge luminescence in ZnSe barrier layer, the transitions from the first conduction subband to the heavy-hole subband in ZnSe0.92Te0.08 layers and [(CdSe)1(ZnSe)2]9 ultra short period superlattice quantum well (SPSLQW) layers have been observed. Experimental results show that ZnSe0.92Te0.08/ZnSe forms a type-I superlattice (SL) in contrast to the type-II ZnSe/ZnTe SL. The pressure coefficients of the EB, E1 and Ew exciton peaks have been determined as 67, 63 and 56 meV/GPa, respectively. With increasing temperature (or pressure), the E1 peak-intensity drastically decreases which is attributed to the thermal effect (or the appearance of many defects in ZnSe0.92Te0.08 under higher pressure).