Insights into the mechanism of shortened developmental duration and accelerated weight gain associated with Wolbachia infection in Hylyphantes graminicola.

Wolbachia infection is known to affect host reproduction and development. To date, however, the underlying mechanism related to the effects of Wolbachia on host development has not yet been reported. Here, we compared the developmental duration and body weight in different instars of Wolbachia-positive (W+ ) and Wolbachia-negative (W- ) spiders (Hylyphantes graminicola) and detected the relative expression levels of 6 insulin-related genes and 3 ecdysone-related genes using reverse transcription qPCR. Results showed that the developmental duration was significantly shortened in W+ spiders compared with W- spiders. Furthermore, W+ spiders were significantly heavier than W- spiders at the 3rd and 4th instars, although no significant differences in body weight were observed after maturity. We also found that the expression levels of insulin-like growth factor-2 mRNA-binding protein-1, insulin-degrading enzyme, and ecdysone-inducible protein-1 genes were significantly down-regulated in W+ spiders compared with W- spiders, whereas the expression levels of insulin-like growth factor-binding protein-1, insulin-like peptide receptor, insulin receptor substrate 2-B, insulin-like, ecdysone-induced protein-2, and ecdysone receptor genes were significantly up-regulated in W+ spiders. Our results suggest that Wolbachia may influence host development by affecting insulin and ecdysone signaling pathways.

Co-infection with Wolbachia and Cardinium may promote the synthesis of fat and free amino acids in a small spider, Hylyphantes graminicola.

Associations between endosymbiotic bacteria and their hosts are widespread in nature and have been demonstrated extensively; however, only a few studies have examined how facultative symbionts affect host nutrition and metabolism. To gain insight into the associations between facultative symbionts and host nutrition and metabolic activity, we detected endosymbiotic infection in a small spider species, Hylyphantes graminicola, and established two infectious strains, i.e., W-C+ (Wolbachia negative, Cardinium positive) and W+C+ (Wolbachia positive, Cardinium positive). We then determined the content of fat and free amino acids in W-C+ and W+C+ spiders, respectively. We also detected the transcriptome of H. graminicola and the expression of genes involved in fat and amino acid metabolism at different host ages. Results showed that fat content in W+C+ spiders was higher than that in W-C+ spiders, and free amino acid content was higher in W+C+ males than W-C+ males, with no difference observed in females. Transcriptome analysis identified 144 (W-C+ vs W+C+) differentially expressed genes (DEGs). Moreover, the expression of five genes involved in fat and amino acid metabolism were significantly up-regulated in the third, fourth, and fifth instar stages in W+C+ spiders. This study indicated that Wolbachia and Cardinium co-infection had a pivotal effect on fat and amino acid synthesis in hosts. Moreover, our results provide strong evidence explaining the long-term coexistence of hosts and endosymbionts.

Specificity of anti-SSB as a diagnostic marker for the classification of systemic lupus erythematosus.

The aim of the present study was to investigate the sensitivity and specificity of anti-Sjögren's syndrome type B (SSB) antibodies for diagnosing systemic lupus erythematosus (SLE) and to understand the correlation between anti-SSB antibodies and the clinical manifestations of SLE. A line immunoassay (LIA) was used to detect the presence of serum anti-SSB antibodies in SLE patients. The clinical manifestations of the patients were recorded to enable their correlation with the serum anti-SSB antibodies to be analyzed. In 25.7% of the 74 SLE patients, the serum was positive for anti-SSB antibodies, whereas only 3.3% of the 30 control cases were positive. The specificity of anti-SSB antibodies for detecting SLE was 96.7%. In anti-SSB antibody-positive SLE patients, the incidence of cheek erythema, alopecia, serositis, secondary Sjögren's syndrome (sSS), leukocytopenia, elevated immunoglobulin (Ig)G and positive presence of anti-Sjögren's syndrome type A (SSA)60 or anti-SSA52 antibodies was higher than in the anti-SSB antibody-negative group (P<0.05). Anti-SSB antibodies are important for the diagnosis of SLE and are associated with cheek erythema, alopecia, serositis, sSS, leukocytopenia, the elevation of IgG and positive presence of anti-SSA60 or anti-SSA52 antibodies.