OBJECTIVETo establish the EST-SSR marker system for Cordyceps by using ESTs of C. bassiana and C. militaris.

METHODThe ESTs of Cordyceps were downloaded from the public database of NCBI, and the redundant ESTs with low quality were removed. The EST-SSR primers were designed by Sequece Seiner 1. 2. And the primers were screened through PAGE-Electrophoresis.

RESULTThe 4 556 non-redundant ESTs which from C. bassiana with total length of 2 953 173 bp were selected. 718 EST-SSRs distributed in 616 ESTs were totally screened out, accounting for 15.8% of the non-redundant ESTs. It was discovered that the average distance of EST-SSSR was 1/4 096 bp in EST-SSRs distribution of C. bassiana. Trinucleotide repeats were the most abundant types with 419 repeated sequences. Regarding to C. militaris, totally 1 363 non-redundant ESTs were acquired, from which 1 117 EST-SSRs were screened, and rate of SSR sites in ESTs was 81.95%. The leading motif of SSR was nucleotide A. The 50 pairs of EST-SSR primers were designed according to the ESTs of C. bassiana, and preliminary test showed the 34 pairs of primers amplified clear fragments,accounting for 68% of all primers. Furthermore, the 39 of the 40 pairs of primers from the ESTs of C. militaris were found to be amplified as the clear fragments, accounting for 97.5%. The phylogenetic analysis revealed that different anamorph of Cordyceps spieces were divided into four branches.

CONCLUSIONThe EST-SSR of Cordyceps had comparably higher utility value. The EST-SSR markers developed from ESTs of C. bassiana and C. militaris had well transferability in Cordyceps. And it was suggested that the EST-SSR markers should be an easy and effective way to assay molecular genetic structure of Cordyceps.

China ; Cordyceps ; classification ; genetics ; DNA Primers ; DNA, Fungal ; genetics ; Databases, Nucleic Acid ; Expressed Sequence Tags ; Genetic Markers ; genetics ; Genome, Fungal ; genetics ; Microsatellite Repeats ; genetics ; Phylogeny ; Polymorphism, Genetic ; Repetitive Sequences, Nucleic Acid ; genetics

ObjectiveTo investigate the association between serum creatinine/cystatin C ratio （CCR） and nonalcoholic fatty liver disease （NAFLD） based on the NHANES database， and to evaluate the potential significance of CCR as an indicator reflecting the metabolic status of the body. MethodsBased on the data from the NHANES database in 1999‍ ‍—‍ ‍2004， a total of 4 217 participants were enrolled and divided into NAFLD group with 1 726 participants and non-NAFLD group with 2 491 participants. CCR was compared between the two groups， and the association between CCR and NAFLD was analyzed. The Wilcoxon rank-sum test was used for comparison of continuous data between two groups， and the chi-square test was used for comparison of categorical data between two groups. The multivariate logistic regression model was used to investigate the association between CCR and NAFLD； CCR was divided into 4 groups based on quartiles， and odds ratio （OR） and 95% confidence interval （CI） in the regression model was calculated with the first quartile as reference. In addition， the restricted cubic spline analysis was used to investigate whether there was a non-linear relationship between CCR and NAFLD， and interaction items were introduced into the Logistic regression model to perform an interaction analysis. Subgroup analyses were performed based on the stratification of variables to investigate the difference in the association between CCR and NAFLD in different populations. ResultsThe non-NAFLD group had a significantly higher CCR than the NAFLD group （Z=-4.76，P<0.01）. The Logistic regression analysis showed that in model 1 without adjustment of variables， CCR was negatively associated with NAFLD （OR=0.993，95%CI：0.989‍ ‍—‍ ‍0.996，P<0.01）， and in model 3 with adjustment of all variables， CCR was still negatively associated with NAFLD （OR=0.986，95%CI：0.981‍ ‍—‍ ‍0.991，P<0.01）. The analysis of CCR based on quartiles showed a significant association between the increase in CCR and the reduction in the risk of NAFLD. In model 3， compared with the individuals with the lowest quartile of CCR， the individuals with the highest quartile of CCR had a significantly lower risk of NAFLD （OR=0.426，95%CI：0.316‍ ‍—‍ ‍0.574，P<0.01）. Further interaction and subgroup analyses showed that the interaction between CCR and age/sex had a statistical significance （P_interaction<0.01 and P_interaction=0.04）. The subgroup analysis based on age showed a more significant association between CCR and NAFLD in the middle-aged population （≤60 years） （OR=0.982，95%CI：0.976‍ ‍—‍ ‍0.987）， and the subgroup analysis based on sex showed a stronger association between CCR and NAFLD in women （OR=0.979，95%CI：0.972‍ ‍—‍ ‍0.986）. ConclusionThis study shows a significant negative association between CCR and NAFLD， and such association is more significant in middle-aged individuals and women.

Epigenetic mechanisms play a crucial role in the development and progression of nonalcoholic fatty liver disease （NAFLD）， especially among lean individuals. The research on related epigenetic mechanisms has provided new clues and directions for revealing the underlying causes and treatment strategies of NAFLD. This article introduces the role of epigenetics in the development and progression of NAFLD among lean individuals in recent years， analyzes the latest research advances in the epigenetics of NAFLD in this population， and briefly describes the basic concepts of epigenetics， including DNA methylation， histone modifications， and non-coding RNA regulation. This article also discusses how epigenetic alterations impact the pathogenesis， disease progression， and treatment strategies of NAFLD in lean individuals.