Biology subjects

Zhang, x.

Publications and source records attributed to Zhang, x..

3 recordsLinked to original sources

bioRxiv2021

Variation of female pronucleus reveal oocyte or embryo abnormality: An expert experience deep learning of non-dark box analysis

BackgroundPronuclear assessment appears to have the ability to distinguish good and bad embryos in the zygote stage, but paradoxical results were obtained in clinical studies. This situation might be caused by the robust qualitative detection of the development of dynamic pronuclei. Here, we aim to establish a quantitative pronuclear measurement method by applying expert experience deep learning from large annotated datasets. MethodsConvinced handle-annotated 2PN images (13419) were used for deep learning then corresponded errors were recorded through handle check for subsequent parameters adjusting. We used 790 embryos with 52479 PN images from 155 patients for analysis the area of pronuclei and the pre-implantation genetic test results. Establishment of the exponential fitting equation and the key coefficient {beta} 1was extracted from the model for quantitative analysis for pronuclear(PN) annotation and automatic recognition. FindingsBased on the female original PN coefficient {beta}1, the chromosome-normal rate in the blastocyst with biggest PN area is much higher than that of the blastocyst with smallest PN area (58.06% vs. 45.16%, OR=1.68 [1.07-2.64]; P=0.031). After adjusting coefficient {beta}1 by the first three frames which high variance of outlier PN areas was removed, coefficient {beta}1 at 12 hours and at 14 hours post-insemination, similar but stronger evidence was obtained. All these discrepancies resulted from the female propositus in the PGT-SR subgroup and smaller chromosomal errors. Conclusion(s)The results suggest that detailed analysis of the images of embryos could improve our understanding of developmental biology. FundingNone

genetics↗

bioRxiv2020

An isothermal method for sensitive detection of Mycobacterium tuberculosis complexes using CRISPR/Cas12a cis- and trans-cleavage

Tuberculosis is still one of the most serious infectious diseases resulting in lethal death worldwide. The traditional method is still not enough to meet the clinical requirements of rapid diagnosis, high specificity and sensitivity. Fast, sensitive and accurate detection of mycobacterium tuberculosis (MTB) is an urgent need for the treatment and control of tuberculosis disease. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated proteins (Cas12a) exhibits strongly nonspecific degradation ability of exogenous single-strand nucleic acid (trans-cleavage) after specific recognition of target sequence. We purified Cas12a protein and selected a proper guide RNA (gRNA) based on conserved sequences of MTB from gRNA library we designed. Then, we proposed a novel method based on recombinase polymerase amplification (RPA) and CRISPR/Cas12a nuclease system for specific and sensitive detection of MTB DNA. The assay based on fluorescence detection pattern showed 4.48 fM of limit of detection (LOD) and good linear correlation of concentration and fluorescence value (R2=0.9775). Also, it showed good performance in distinguishing other bacteria. Furthermore, its clinical performance was evaluated by 193 samples and showed sensitivity of 99.29% (139/140) and specificity of 100% (53/53) at 99% confidence interval, respectively, compared with culture method. The CRISPR/Cas12a system showed good specificity, excellent sensitivity and accuracy for MTB detection, and it meets requirements of MTB detection in clinical samples and has great potential for clinical translation.

molecular biology↗

bioRxiv2018

Effects of different pretreatments on flavonoids and antioxidant activity of Dryopteris erythrosora leave

Flavonoids with wide bioactivity for medcine are vital secondary metabolite of plant. The factors influenced on flavonoids had been reported. However, as the key processes lead to metabolite alterations, the influences of the different pretreatments of samples on flavonoids and antioxidant activity of ferns were with little information. Therefore, Dryopteris erythrosora leaves were chosen as the materials for analyzing flavonoids alterations, which would not only provide the significant basic data for flavonoid metabolism of fern, but also for further developing fern resources. The results showed that a) The total flavonoids contents of D. erythrosora leaves with different pretreatments were obviously different. The total flavonoid contents of samples, which was dried in shade firstly and then dried at 75 {degrees}C in oven, finally smashed, was the highest (7.6%), but that of samples, which was quickly dried at 75 {degrees}C in oven directly after cleaning and then smashed, was the lowest (2.17%); b) Antioxidant activities of D. erythrosora leaves with different pretreatments were variant. Samples, which were dried in shade firstly and then dried at 75 {degrees}C in oven, finally smashed and samples which were firstly dried in the sun and then dried at 75 {degrees}C in oven, ultimately smashed, both showed stronger antioxidant activity; c) Total twenty-three flavonoids with four different pretreatments were tentatively identified by HPLC-ESI-TOF-MS. In conlusion, a) The influences of different pretreatments on flavonoids and antioxidant activity of D. erythrosora Leaves were obvious. b) The best pretreatment in respect to conserving fern medical application was drying in shade firstly and then drying at 75 {degrees}C in oven, finally smashed.

plant biology↗