No abstract

No abstract

The Cholesterol 7-desaturase gene plays an important role in insect ecdysone synthesis, but its role in ovarian development has not been reported. In this study, characteristics and the phylogenetic relationship of Cholesterol 7-desaturase were identified by bioinformatics. qPCR showed that the Mn-CH7D gene was highly expressed in the ovary, which was much higher than that in other tissues, and the expression level of Mn-CH7D reached the highest level at the third stage of the ovarian development stage (O-III). During embryonic development, the Mn-CH7D gene expression was highest in the zoea stage. The function of the Mn-CH7D gene was explored by RNA interference. The experimental group was injected with Mn-CH7D dsRNA through the pericardial cavity of M. nipponense, while the control group was injected with the same volume of dsGFP. Statistical analysis of gonadal development and GSI calculation showed that the silencing of Mn-CH7D resulted in the suppression of gonadal development. In addition, the molting frequency of the experimental group was significantly lower than that of the control group during the second molting cycle after silencing Mn-CH7D. On the seventh day after silencing, ecdysone content in the experimental group was significantly reduced. These results demonstrated that the Mn-CH7D gene played a dual role in ovarian maturation and molting of M. nipponense.

Most of the shape classification methods are based on a single closed contour. However, practical shapes always have complex contours, for example, a combination of multiple open contours. How to accurately identify complex shapes is an unsolved problem. In this research, a novel method is proposed to classify complex shapes. The proposed method firstly encodes a complex shape to an angle code and a sparsity code, then input these codes to a 1-D CNN for extracting features and classification. Experiments on two datasets show this novel method is superior in terms of classification accuracy. These two datasets are practical shape dataset collected by this paper on internet and MPEG-7 CE-1 Part B. The proposed method achieves higher classification accuracy than compared methods. In order to show the performance of the proposed method on each class, the accuracy on each class is analyzed. Ablation experiment is conducted to show the contribution of each module in the network. The result shows that each module is meaningful in the network, because without any module the accuracy drops.

Macrobrachium nipponense, is an important economic indigenous prawn in China, which is widely distributed in freshwater in China, Japan and Southeast Asia. In this study, D-loop region sequences was used to investigate the genetic diversity and population structure of 22 wild populations of M. nipponense through China, containing the major rivers and lakes of China. Totally 475 valid D-loop sequences from 22 populations with a length of 1110bp were obtained, and 348 variation sites and 221 haplotypes were detected. A total of 221 haplotypes were defined in 22 populations.Hap48 was the dominant haplotype, accounting for about 13%. The haplotype diversity (h) was ranged from 0.1630 (BN) ~1.0000 (AR) and the nucleotide diversity π value ranged from 0.001164 (MR) ~ 0.037168 (NR). The pairwise genetic differentiation index (FST) ranged from 0.00344 to 0.91243 and most pair-wised FST was significant (P < 0.05). The lowest FST was displayed in MR and JLR population and the highest was between NDR and NR. The phylogenetic tree of genetic distance based on UPGMA showed that all populations were divided into two branches. The DC, NDR, JLR and MR populations were clustered into one branch. The neutral test and mismatch distribution results showed that M. nipponense populations were not experienced expanding and kept a steady increase. Taken together, a joint resources protection and management strategy for M. nipponense have been suggested based on the results of this study for its sustainable use.