Seasonal flexibility of the gut structure and physiology in Eremias multiocellata.

Although gut seasonal plasticity has been extensively reported, studies on physiological flexibility, such as water-salt transportation and motility in reptiles, are limited. Therefore, this study investigated the intestinal histology and gene expression involved in water-salt transport (AQP1, AQP3, NCC, and NKCC2) and motility regulation (nNOS, CHRM2, and ADRB2) in desert-dwelling Eremias multiocellata during winter (hibernating period) and summer (active period). The results showed that mucosal thickness, the villus width and height, the enterocyte height of the small intestine, and the mucosal and submucosal thicknesses of the large intestine were greater in winter than in summer. However, submucosal thickness of the small intestine and muscularis thickness of the large intestine were lower in winter than in summer. Furthermore, AQP1, AQP3, NCC, nNOS, CHRM2, and ADRB2 expressions in the small intestine were higher in winter than in summer; AQP1, AQP3, and nNOS expressions in the large intestine were lower in winter than in summer, with the upregulation of NCC and CHRM2 expressions; no significant seasonal differences were found in intestinal NKCC2 expression. These results suggest that (i) intestinal water-salt transport activity is flexible during seasonal changes where AQP1, AQP3 and NCC play a vital role, (ii) the intestinal motilities are attenuated through the concerted regulation of nNOS, CHRM2, and ADRB2, and (iii) the physiological flexibility of the small and large intestine may be discrepant due to their functional differences. This study reveals the intestinal regulation and adaptation mechanisms in E. multiocellata in response to the hibernation season.

Seasonal flexibility of kidney structure and factors regulating water and salt in Eremias multiocellata.

Although sodium and water reabsorption by the kidney plays a major role in maintaining body fluid homeostasis, the seasonal response of renal morphology and the factors involved in water and salt regulation are not well known, especially in reptiles. Eremias multiocellata is a typical desert-dwelling lizard. Here, we compared water and salt regulation of E. multiocellata in winter (hibernation), spring (emerging from hibernation), and summer (active) according to histomorphometry and the expression of genes such as those encoding aquaporins (AQP1, AQP2, AQP3), the Na+-Cl- cotransporter (NCC), the Na+-K+-2Cl- cotransporter (NKCC2), renin (Ren), angiotensin II receptor type 2 (AT2R), and endothelial nitric oxide synthase (eNOS) in the kidneys. The results showed that the area of Bowman's capsule and the glomerular density were lower in winter compared to summer and spring, and the lumen size of the DCT, PCT, and IS was greater in spring than in summer. Compared to summer and spring, the expression of AQP1, AQP3, NCC, NKCC2, Ren, and eNOS was significantly decreased in winter, whereas the expression of AQP2 and AT2R remained high. These results indicate that E. multiocellata balances its water budget via morpho-functional changes in different seasons. Although renal function was temporarily attenuated during winter, the regulation of aquaporins genes was not synchronous, indicating the complexity and particularity of water and salt regulation in desert lizards when facing the constraints of harsh environmental conditions, seasonal variations, and hibernation. These results will enrich the understanding of water and salt regulation mechanisms in desert reptiles.

Diagnostic efficacy of indirect haemagglutination assay for detection of Schistosoma japonicum infections among boatmen and fishermen in the Dongting Lake region / 中国血吸虫病防治杂志

OBJECTIVE@#To evaluate the diagnostic efficacy of indirect haemagglutination assay (IHA) for detection of Schistosoma japonicum infections among boatmen and fishermen in Dongting Lake region, so as to provide insights into improving the schistosomiasis surveillance program among boatmen and fishermen.@*METHODS@#The boatmen and fishermen were detected for S. japonicum infections using IHA and Kato-Katz technique or miracidium hatching test nylon gauze simultaneously at schistosomiasis testing sites in the anchor sites for boatmen and fishermen in the Dongting Lake region during the period from 2014 to 2016, and using IHA for serological screening followed by parasitological testing of seropositives during the period from 2017 to 2019. The sensitivity and specificity of IHA were evaluated for detection of S. japonicum infections among boatmen and fishermen, with the 2014-2016 parasitological testing results as a gold standard. In addition, the seroprevalence of S. japonicum infections was compared among boatmen and fishermen with different characteristics and among years.@*RESULTS@#A total of 306 schistosomiasis testing sites were assigned for boatmen and fishermen, and a total of 143 360 person-time boatmen and fishermen were tested for S. japonicum infections in the Dongting Lake region from 2014 to 2019. The sensitivity and specificity of IHA were 69.9%, 97.3% and 96.1% (χ2 = 74.6, P < 0.05), and 70.9%, 74.5% and 71.9% for detection of S. japonicum infections from 2014 to 2016 (χ2 = 29.4, P < 0.05), respectively. The seroprevalence of S. japonicum infections reduced from 30.3% in 2014 to 1.8% in 2019 among boatmen and fishermen, appearing an overall tendency towards a decline (Z = 1 552.4, P < 0.05). In addition, male, individuals at ages of 45 to 60 years, full-time boatmen and fishermen were more likely to be seropositive for S. japonicum infections (all P values < 0.05).@*CONCLUSIONS@#The seroprevalence of S. japonicum infections appeared a tendency towards a decline among boatmen and fishermen in the Dongting Lake region year by year from 2014 to 2019. IHA presented a high efficacy for screening of S. japonicum infections among boatmen and fishermen in the Dongting Lake region.

Taxonomic rank of human parasites / 中国血吸虫病防治杂志

Biological category is effective to indicate the evolution of organism populations between past and present. Conventional taxonomy of human parasites mainly depends on important morphological features, which suffers from a problem of categorizing related-genera species with similar morphological characteristics. With recent advances in molecular biological technologies, the effective applications of mitochondrial and ribosomal biomarkers and sequencing greatly improve the development of the taxonomic rank of human parasites. Worldwide, the classification of human parasites have been continuously revised and improved. Hereby, we re-categorize parasitic Protozoa, Trematoda, Cestoda and Nematoda, so as to provide insights into the researches on molecular systematics and genetic evolution of human parasites.