BmC/EBPZ gene is essential for the larval growth and development of silkworm, Bombyx mori.

The genetic male sterile line (GMS) of the silkworm Bombyx mori is a recessive mutant that is naturally mutated from the wild-type 898WB strain. One of the major characteristics of the GMS mutant is its small larvae. Through positional cloning, candidate genes for the GMS mutant were located in a region approximately 800.5 kb long on the 24th linkage group of the silkworm. One of the genes was Bombyx mori CCAAT/enhancer-binding protein zeta (BmC/EBPZ), which is a member of the basic region-leucine zipper transcription factor family. Compared with the wild-type 898WB strain, the GMS mutant features a 9 bp insertion in the 3'end of open reading frame sequence of BmC/EBPZ gene. Moreover, the high expression level of the BmC/EBPZ gene in the testis suggests that the gene is involved in the regulation of reproduction-related genes. Using the CRISPR/Cas9-mediated knockout system, we found that the BmC/EBPZ knockout strains had the same phenotypes as the GMS mutant, that is, the larvae were small. However, the larvae of BmC/EBPZ knockout strains died during the development of the third instar. Therefore, the BmC/EBPZ gene was identified as the major gene responsible for GMS mutation.

Genetic and transcriptome analysis of the smb mutant in Bombyx mori.

More than 600 mutations have been discovered in the history of silkworm domestication. It is important to study the formation mechanism of these mutations to further understand the life and development process of silkworms and agricultural pest control. The silkworm mutant smb was isolated from silkworm strain NCV, and transcriptome analysis was performed on the silkworm mutant. 796 differentially expressed genes (DEGs) were detected at 48 h of the second instar stage with 669 genes significantly upregulated and 127 genes significantly downregulated. During the GO enrichment analysis, it was found that the enrichment of biological processes was mainly concentrated in proteolysis, carbohydrate metabolism, aminoglycan metabolism, organic substance metabolism, protein metabolism and so on. Based on the analysis of KEGG pathways, it revealed that the pathways enriched in lysosomes, AMPK signaling, fatty acid metabolism, PPAR signaling, galactose metabolism, and protein digestion and absorption were the most significant. Through these most significantly enriched GO terms and KEGG pathways, DEGs consistent with the phenotypic characteristics of the smb mutant were identified, including small body size, slow development, and successive death after the fourth instar. These results provided experimental evidence for the potential formation mechanism of smb mutants.

Development of a time-resolved immunochromatographic strip for rapid and quantitative determination of deoxynivalenol.

Deoxynivalenol (DON) contamination of food crops and feeds is almost impossible to avoid completely; however, through best management practices, this risk can be effectively managed and maximumly mitigated. Accurate and rapid detection of DON contamination as early in the entire value chain as possible is critical. To achieve this goal, we developed a DON test strip based on time-resolved fluorescence immunoassay (TRFIA) and a specific DON monoclonal antibody for the rapid quantification of DON in food crops and feeds. The strip displayed a good linearity (R 2 = 0.9926), with a limit of quantification of 28.16 µg/kg, a wide linear range of 50 ~ 10,000 µg/kg. The intra-batch coefficient of variation (CV) and the inter-batch CV was <5.00 and 6.60%, respectively. This TRFIA-DON test strip was applied to detect DON in real samples, and the accuracy and reliability were confirmed by liquid chromatography-mass spectrometry (LC-MS/MS). Results showed that the relative standard deviation between the DON strips and LC-MS/MS was <9%. The recovery rates in corn samples ranged from 92 to 104%. The established TRFIA-DON test strip had the characteristics of high sensitivity, high accuracy, and a wide linear range which was suitable for rapid and quantitative determination of DON in food crops and feeds at both on-site and laboratory.

Comparative analysis of testis transcriptome between a genetic male sterile line (GMS) and its wild-type 898WB in silkworm, Bombyx mori.

The silkworm, Bombyx mori, is an important model organism of lepidopteran insects, and its testis is a main male reproductive organ and spermatogenesis place. Studying the testis helps to understand the mechanisms of genetic sterility of lepidopteran insects and to achieve sterile insect technique (SIT) for pest control. Herein, we performed a comparative transcriptome analysis of testes between three biological replicates of the GMS mutant and wild strain 898WB, respectively. In total, 1872 up-regulated genes and 1823 down-regulated genes were identified in the testis of the GMS mutant. Several genes contribute significantly to spermatogenesis and testis development, such as "serine/threonine protein kinase", "organic cation transporter protein", "tyrosine protein kinase", "lncRNAs" and "immune-associated genes". The KEGG pathway analysis shows that the DEGs were annotated to 123 pathways, and 10 pathways were significantly enriched, such as "metabolic pathway", "biosynthesis of amino acids", and "phagosome-lysosome pathway", which are associated with testis development and spermatogenesis. The results of the qPCR expression were consistent with the RNA-seq data, which shows that the RNA-seq results were accurate. The DEGs of the testes between GMS mutant and 898WB were screened by RNA-Seq technology, which provides a reliable reference to understand the molecule mechanism of male sterility of the GMS mutant.

Genetic analysis and transcriptome analysis of the mini mutant of the silkworm, Bombyx mori.

The expression levels of some intrinsic genes, protease activity, and regulation of signaling pathways were distinct during different growth and development stages in the silkworm, Bombyx mori. The silkworm mutant mini was discovered from the normal silkworm strain S8V, and the body-size of the mini mutant was smaller than the wild-type from the second-instar and the difference became more significant in the following stages. In this study, genetic analysis of mini mutant showed that mini mutant was controlled by a single recessive gene, manifested as homozygous lethal. Then, the transcriptome analysis of the mini mutant indicated that 2944 differentially expressed genes (DEGs) were identified from the silkworm in the 48 h of the second-instar, of which 1638 genes in the mini mutants were upregulated and 1306 genes were downregulated. These DEGs were mainly distributed in the biological process, cellular component, and molecular function. The functional annotation based on the KEGG database showed that these genes were mainly clustered in metabolic pathways, fatty acid metabolism pathways, ribosome biogenesis in eukaryotes, and so on. Further analysis indicated that some genes involved in the growth and metabolism including enzyme genes, juvenile hormone, and ecdysone exhibited different transcriptional levels. These results provided new experimental evidence regarding the mechanism of the underlying formation of mini mutants.

Genetic analysis of 50 Y-STR loci in Dong, Miao, Tujia, and Yao populations from Hunan.

To investigate the genetic polymorphism of Y chromosome short tandem repeat (Y-STR) loci in Dong, Miao, Tujia, and Yao minority populations from Hunan Province, China. Fifty Y-STRs (DYS392, DYS389I/II, DYS447, DYS438, DYS527, DYS645, DYS596, DYS391, DYS456, DYS19, DYS593, DYS448, DYS627, DYS557, DYS437, DYS481, DYS533, DYS390, DYS385, DYF387S1, DYS460, DYS393, Y_GATA_H4, DYS439, DYS635, DYS444, DYS643, DYS549, DYS576, DYS570, DYS458, DYS449, DYS518, DYS531, DYS630, DYS622, DYS552, DYS510, DYS459a/b, DYS446, DYS443, DYS587, Y_GATA_A10, DYS520, DYS522) were analyzed for 2553 unrelated healthy male individuals from Hunan (643 Dong males, 666 Miao males, 633 Tujia males, 611 Yao males) using AGCU Y37 and AGCU Y SUPP STR amplification system. There were 624 different haplotypes in 643 unrelated Dong males, 662 in 666 unrelated Miao males, 627 in 633 unrelated Tujia males, and 587 in 611 unrelated Yao males. The haplotype diversities of Dong, Miao, Tujia, and Yao were determined as 0.999879, 0.999982, 0.999970, and 0.999860, respectively. Analysis of molecular variance (AMOVA) tests demonstrated that genetic distance between Miao and Tujia was the smallest (0.0003), while the genetic distance between Dong and Yao was the largest (0.0252). The 50 Y-STR loci in the four minority populations from Hunan Province revealed a highly polymorphic genetic distribution, which showed a high potential for population genetics and forensic practice.

The validation study of a novel assay with 30 slow and moderate mutation Y-STR markers for criminal investigation and database applications.

The Y chromosome short tandem repeat (Y-STR) haplotyping method has been widely used in forensic applications. However, the existing Y-STR panels are not the ideal tools for criminal investigation and database applications because of their relatively low discriminatory capacity (DC) or high mutation rates. In the present study, the multiplex PCR assay (AGCU Y30) for simultaneous amplification of 30 slowly and moderately mutated Y-STR loci labeled by 6-dye fluorescence was developed and validated. The AGCU Y30 assay was capable of amplification purified DNA from casework and database samples on FTA™ cards in direct amplification module with a 10 µL reaction volume. Furthermore, the genetic diversities and forensic parameters of AGCU Y30 were performed using 719 unrelated male samples, demonstrating its high level of genetic polymorphisms and DC in Nantong Han population. This validation study demonstrated good sensitivity, mixture samples, inhibitor tolerance, precision, and concordance for the AGCU Y30, which is suitable for forensic investigation and database construction.

Developmental validation of forensic DNA-STR kits: Expressmarker 16+10Y and expressmarker 16+18Y.

DNA-STR analysis is widely used in the forensic science field and obtaining results in shorter time is highly demanded. The developed forensic STR Kit, referred to as Expressmarker 16+10Y (EX16+10Y) and Expressmarker 16+18Y (EX16+18Y), could amplify the common autosomal and Y chromosome STR loci simultaneously. The kits are validated by a series of tests, including DNA mixtures, stutter ratios, PCR based studies, species specificities, inhibitors, sensitivity, sizing precision, reproducibility and parallel tests. The results demonstrated that EX16+10Y and EX16+18Y were useful tools for rapid criminal investigation.

Differentially expressed genes in the cuticle and hemolymph of the silkworm, Bombyx mori, injected with the fungus Beauveria bassiana.

The most important pathogenic fungus of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), is Beauveria bassiana (Balsamo-Crivelli ) Vuillemin (Hypocreales: Clavicipitaceae), which causes significant damage to sericulture production. Therefore, diagnosing fungal disease and developing new control measures are crucial to silk production. To better understand the responsive and interactive mechanisms between the host silkworm and this fungus, variations in silkworm gene expression were investigated using the suppression subtractive hybridization method following the injection of B. bassiana conidia. Two cDNA libraries were constructed, and 140 cDNA clones were isolated. Of the 50 differentially expressed genes identified, 45 (112 clones) were identified in the forward library, and 5 (28 clones) were identified in the reverse library. Expression profiling of six of these genes by quantitative polymerase chain reaction (qPCR) verified that they were induced by the fungal challenge. The present study provides insight into the interaction between lepidopteran insects and pathogenic fungi.