Exploration of Parascaris species in three different Equus populations in China.

BACKGROUND: The roundworms, Parascaris spp., are important nematode parasites of foals and were historically model organisms in the field of cell biology, leading to many important discoveries. According to karyotype, ascarids in Equus are commonly divided into Parascaris univalens (2n = 2) and Parascaris equorum (2n = 4). METHODS: Here, we performed morphological identification, karyotyping and sequencing of roundworms from three different hosts (horses, zebras and donkeys). Phylogenetic analysis was performed to study the divergence of these ascarids based on cytochrome c oxidase subunit I (COI) and internal transcribed spacer (ITS) sequences. RESULTS: Karyotyping, performed on eggs recovered from worms of three different Equus hosts in China, showed two different karyotypes (2n = 2 in P. univalens collected from horses and zebras; 2n = 6 in Parascaris sp. collected from donkeys). There are some differences in the terminal part of the spicula between P. univalens (concave) and Parascaris sp. (rounded). Additionally, it was found that the egg's chitinous layer was significantly thicker in Parascaris sp. (> 5 µm) than P. univalens (< 5 µm) (F(2537) = 1967, P < 0.01). Phylogenetic trees showed that the sequences of Parascaris from Equus hosts were divided into two distinct lineages based on sequences of the COI and ITS. CONCLUSIONS: Comparing the differences in roundworms collected from three different Equus hosts, this study describes a Parascaris species (Parascaris sp.) with six chromosomes in donkeys. It is worth noting that the thickness of the chitinous layer in the Parascaris egg may serve as a diagnostic indicator to distinguish the two roundworms (P. univalens and Parascaris sp.). The Parascaris sp. with six chromosomes in donkeys in the present study may be a species of P. trivalens described in 1934, but the possibility that it is a new Parascaris species cannot be ruled out. Both karyotyping and molecular analysis are necessary to solve the taxonomic problems in Parascaris species.

Gene rearrangements in the mitochondrial genome of ten ascaris species and phylogenetic implications for Ascaridoidea and Heterakoidea families.

The Ascaridoidea family and Heterakoidea family are the most common and typical representative of large parasites. Although our understanding of these parasites' diversity has expanded by analyses of some mitochondrial genes, there is limited information on these species' evolutionary rates. Here we determined ten complete mitogenome sequences of five subfamilies of Ascaridoidea and one subfamily of Heterakoidea. The phylogenetic tree divided the Ascaridoidea into six monophyletic major clades, and the divergence time of Heterakoidea family and Ascaridoidea family can be placed during the early Carboniferous Period (300-360 Mya). The reconstruction of the ancestral state showed that the gene orders of all species in Ascaridoidea were conserved, and the Heterakoidea had obvious genome rearrangement. The conserved blocks between them were divided into five and the main types are tandem-duplication/random loss (TDRL). These results will help to better understand the gene rearrangements and evolutionary position of ascaris species.

Equus roundworms (Parascaris univalens) are undergoing rapid divergence while genes involved in metabolic as well as anthelminic resistance are under positive selection.

BACKGROUND: The evolution of parasites is often directly affected by the host's environment. Studies on the evolution of the same parasites in different hosts are of great interest and are highly relevant to our understanding of divergence. METHODS: Here we performed whole-genome sequencing of Parascaris univalens from different Equus hosts (horses, zebras and donkeys). Phylogenetic and selection analyses were performed to study the divergence and adaptability of P. univalens. RESULTS: At the genetic level, multiple lines of evidence indicate that P. univalens is mainly separated into two clades (horse-derived and zebra & donkey-derived). This divergence began 300-1000 years ago, and we found that most of the key enzymes related to glycolysis were under strong positive selection in zebra & donkey-derived roundworms, whereas the lipid-related metabolic system was under positive selection in horse-derived roundworms, indicating that the adaptive evolution of metabolism has occurred over the past few centuries. In addition, we found that some drug-related genes showed a significantly higher degree of selection in diverse populations. CONCLUSIONS: This work reports the adaptive evolution and divergence trend of P. univalens in different hosts for the first time. Its results indicate that the divergence of P. univalens is a continuous, dynamic process. Furthermore, the continuous monitoring of the effects of differences in nutritional and drug histories on the rapid evolution of roundworms is conducive to further understanding host-parasite interactions.

A survey of Cryptosporidium prevalence among birds in two zoos in China.

BACKGROUND: Cryptosporidiosis is an important zoonotic protozoan disease worldwide, but few studies on this disease have been performed in wild birds; thus, our knowledge of this disease is insufficient, even in zoo birds. Animals in zoos are possible zoonotic disease reservoirs, potentially resulting in zoonotic agent spillover to humans; accordingly, our understanding of such phenomena should be improved. METHODS: A total of 263 fresh fecal samples from 43 avian species were randomly collected from the Beijing Zoo and Harbin North Forest Zoo and screened for the prevalence of Cryptosporidium by 18S rRNA gene sequencing. Cryptosporidium species were distinguished based on the combined results of phylogenetic tree and genetic distance analyses conducted with the inclusion of seven avian Cryptosporidium species and 13 avian Cryptosporidium genotypes. The genetic diversity of Cryptosporidium parvum among different hosts, including humans, cattle, dogs, and birds, and the genetic diversity of avian C. parvum among avian hosts in China, Iraq and Brazil were determined based on C. parvum 18S rRNA haplotypes. RESULTS: The results of PCR targeting the 18S rRNA gene revealed that 1.9% (5/263) of the samples were Cryptosporidium-positive. Four of the five Cryptosporidium-positive samples originated from white cranes (Grus leucogeranus), and one originated from a flamingo (Phoenicopteridae). Avian C. parvum isolates, including the isolates examined in the present study, showed gene flow with other isolates from different types of hosts, including humans, cattle and dogs, indicating that zoo birds potentially pose zoonotic and pathogenic risks to humans and animals. Additionally, gene flow between avian C. parvum isolates from China and Brazil was detected. CONCLUSIONS: To the best of our knowledge, our results demonstrate C. parvum infection in a flamingo (Phoenicopteridae) and white cranes (Grus leucogeranus) for the first time. The results of our study provide an important reference for understanding the host range, biological characteristics, and molecular epidemiology of C. parvum.

Quantitative flow ratio-guided residual functional SYNTAX score for risk assessment in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention.

BACKGROUND: Functional incomplete revascularisation (IR) is associated with a higher risk of major adverse cardiac events (MACE) during long-term follow-up in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI). AIMS: This study aimed to investigate the prognostic ability of quantitative flow ratio (QFR)-guided residual functional SYNTAX score (Q-rFSS) and functional IR in STEMI patients undergoing PCI. METHODS: In total, 354 consecutive STEMI patients who successfully underwent PCI were included. Q-rFSS was defined as residual SYNTAX score (rSS) measured only in vessels with QFR ≤0.8. The primary outcome was MACE (a composite of all-cause mortality, myocardial infarction, and ischaemia-driven revascularisation) at 2 years. RESULTS: At two-year follow-up, functional IR (Q-rFSS ≥1) showed significantly higher risk for MACE than functional complete revascularisation (CR) (Q-rFSS=0) (functional IR vs CR, 22.0% vs 7.4%; hazard ratio [HR] 3.21; 95% confidence interval [Cl]: 1.74 to 5.91; p<0.001). The area under the curve (AUC) of Q-rFSS (0.738, 95% CI: 0.659 to 0.817) was significantly greater than that of rSS (0.648, 95% CI: 0.547 to 0.749). The C-statistic for MACE also increased after the addition of Q-rFSS to the clinical risk factors. Q-rFSS significantly improved risk classification compared with rSS (net reclassification improvement 0.439, 95% CI: 0.201 to 0.548; p<0.001). CONCLUSIONS: Functional IR is associated with higher risk of MACE during long-term follow-up in STEMI patients undergoing PCI. Q-rFSS has a better prognostic ability for the risk of MACE.

Association of stress hyperglycemia ratio with intracoronary thrombus burden in diabetic patients with ST-segment elevation myocardial infarction.

BACKGROUND: Large intracoronary thrombus burden is not rare during primary percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI). Stress hyperglycemia is independently associated with poor prognosis. However, the underlying relationship between stress hyperglycemia and thrombus burden remains unknown. This study aims to investigate the association of stress hyperglycemia, evaluated by the combination of acute and chronic glycemic levels, with intracoronary thrombus burden in diabetic patients with STEMI. METHODS: We enrolled 227 consecutive diabetic patients with STEMI undergoing primary PCI within 12 hours after symptom onset. Stress hyperglycemia was estimated using the stress hyperglycemia ratio (SHR), which was calculated as admission glycemia divided by estimated average glucose derived from glycosylated hemoglobin. Based on reclassified angiographic thrombolysis in myocardial infarction (TIMI) thrombus grades, patients were divided into small thrombus burden (STB) group (TIMI thrombus grades <4) and large thrombus burden (LTB) group (TIMI thrombus grades 4 or 5). RESULTS: Of the entire study population, 77 (33.9%) patients were categorized as LTB group, whereas 150 (66.1%) patients presented with STB. The mean age was 64.1 years, and 80.6% of the patients were male. The SHR levels were significantly higher in patients with LTB than in those with STB [1.31; interquartile range (IQR): 1.13-1.48 versus 1.11; IQR: 0.96-1.32; P<0.001]. The predictive performance of SHR for LTB was moderate (area under the curve: 0.669; 95% confidence interval: 0.604-0.730; P<0.001), with the best cut-off value 1.19 (sensitivity 71.4%, specificity 64.7%). The incidence of LTB with SHR ≥1.19 was significantly higher compared with SHR <1.19 (50.9% versus 18.5%; P<0.001). Based on the multivariable logistic regression analysis, the high SHR (≥1.19) was found to be an independent predictor of LTB following adjustment for baseline clinical confounders. CONCLUSIONS: A high SHR value was independently associated with large thrombus burden and has a better predictive value than glycemia at admission in diabetic patients with STEMI undergoing primary PCI. Stress hyperglycemia may play an important role on the intracoronary thrombus formation.

Cloning, expression and characterisation of a promising mosquitocidal gene.

A new mosquitocidal gene, cyt1Aa6, was isolated and cloned from the novel Bacillus thuringiensis strain LLP29, previously isolated from the phylloplane of Magnolia denudata. Nucleotide sequence analysis of cyt1Aa6 indicated that the open reading frame consisted of 750 base pairs, encoding 249 amino acid sequences with a calculated molecular weight of 27.3681 kDa and a PI value of 4.77. An homological comparison revealed that the cyt1Aa6 amino acid sequence was 99% identical with those of known Cyt1Aa proteins. In addition, the cyt1Aa6 gene was successfully expressed in Escherichia coli BL21. Bioassays on Aedes albopictus showed that Bt LLP29 and the expressed BL21 were both toxic to 3rd-instar mosquito larvae. The isolation of cyt1Aa6 provides new opportunities for selecting new strains and to obtain novel B. thuringiensis products based on its toxins.

[Study on adsorption of bisphenol A from aqueous solution on modified activated Carbons].

A commercial activated carbon (WV A1100) was modified with nitric acid, sodium hydroxide and thermal treatment in an atmosphere of N2. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pH(PZC) and Boehm titration. The results indicated that the specific surface area of the W20 remarkably decreased after oxidized by nitric acid. But the amount of surface acidic oxygen-containing functional groups of the oxidized sample increased compared to the W20 and resulting in the points of zero charge (pH(PZC)) changed from 4.95 to 1.50. The changes of surface chemical properties of thermal treatment and sodium hydroxide treatment were opposite to the oxidized sample, as a result, the pH(PZC) of them was changed to near pH 7.0. However, a 43.81% surface area of W20 was also diminished by thermal treatment. Furthermore, the results of BPA adsorption indicated that the oligomerization of BPA on the surface of activated carbon could not be formed through oxidative coupling reactions in the presence of dissolved oxygen. And the data of BPA adsorption on original sample, thermal and sodium hydroxide treatment sample were fitted to the Langmuir isotherm model well. Whereas the Freundlich isotherm model described the adsorptive behavior of the oxidized sample better. In addition, the adsorption capacity of thermal treatment sample was the highest and its saturated adsorption capacity reached 526.32 mg/g. The value was three times higher than that of the oxidized sample. Combined with the results of characterization, it was found that the hydrophobic nature and zero of net charge density of carbon surface were the main factors to affect the BPA adsorption on activated carbons and the adsorption is based on pi-pi theory.

Effect of pH on MnOx/GAC catalyzed ozonation for degradation of nitrobenzene.

The effect of pH on MnO(x)/GAC heterogeneous catalytic ozonation was investigated. Nitrobenzene was used as a model refractory organic pollutant. It was found that in MnO(x)/GAC catalytic ozonation, the degradation efficiency of nitrobenzene was higher under low pH conditions (pH 2.74-3.52) than that under high pH conditions (pH 6.72-9.61). This result was different from the case of ozonation alone, in which higher pH had positive effect on the degradation of nitrobenzene due to the formation of hydroxyl radical. In the presence of MnO(x)/GAC catalyst, ozone decomposition was accelerated, and higher pH condition favored ozone decomposition. It was assumed that hydroxyl radicals might not be the dominating active species in the catalytic oxidation, for the presence of t-butanol did not have any influence on MnO(x)/GAC heterogeneous catalytic ozonation. Adsorption of organic micropollutants on MnO(x)/GAC catalyst was an important step and would have direct influence on the effectiveness of catalytic oxidation. It was assumed that the organic pollutants might be further decomposed on the surface of catalyst.