Physiological Adaptive Strategies of Oil Seed Crop Ricinus communis Early Seedlings (Cotyledon vs. True Leaf) Under Salt and Alkali Stresses: From the Growth, Photosynthesis and Chlorophyll Fluorescence

Ricinus communis is an important energy crop and is considered as one of the most potential plants for salt-alkali soil improvement in Northeast China. Early seedling stage (such as the cotyledon expansion stage) is always a vulnerable stage but plays a vital role in plant establishment, especially under stress conditions. However, little information exists concerning the function of cotyledon and the relationship between cotyledon and true leaf in the adaptation to salt stress and alkali stress of this species. Here, Ricinus communis seedlings were treated with varying (40, 80 and 120 mM) salinity (NaCl) and alkalinity (NaHCO3), growth, photosynthesis, and chlorophyll fluorescence of cotyledons and true leaves were measured. The results showed that the biomass, photosynthetic parameters, and the qp value of both cotyledons and true leaves decreased with increasing salt-alkali stress, and the decrease in biomass, gs and Tr, of true leaves were much greater than that of cotyledons. Salt-alkali stress only reduced photosynthetic pigments and ΦPSII in cotyledons, but did not affect those in true leaves. Additionally, the Fv/Fm and NPQ between cotyledons and true leaves showed different trends in salinity and alkalinity. The results suggested that alkali stress could cause much more damage to the castor bean seedlings, and different physiological responses and adaptive strategies are found in cotyledons and true leaves under salt-alkali stress. This study will help us develop a better understanding of the adaptation mechanisms of cotyledon and true leaf during early seedling stage of castor bean plant, and also provide new insights into the function of cotyledon in Ricinus communis under salt-alkali stress conditions

Cell tracking using deep neural networks with multi-task learning

Cell tracking plays crucial role in biomedical and computer vision areas. As cells generally have frequent deformation activities and small sizes in microscope image, tracking the non-rigid and non-significant cells is quite difficult in practice. Traditional visual tracking methods have good performances on tracking rigid and significant visual objects, however, they are not suitable for cell tracking problem. In this paper, a novel cell tracking method is proposed by using Convolutional Neural Networks (CNNs) as well as multi-task learning (MTL) techniques. The CNNs learn robust cell features and MTL improves the generalization performance of the tracking. The proposed cell tracking method consists of a particle filter motion model, a multi-task learning observation model, and an optimized model update strategy. In the training procedure, the cell tracking is divided into an online tracking task and an accompanying classification task using the MTL technique. The observation model is trained by building a CNN to learn robust cell features. The tracking procedure is started by assigning the cell position in the first frame of a microscope image sequence. Then, the particle filter model is applied to produce a set of candidate bounding boxes in the subsequent frames. The trained observation model provides the confidence probabilities corresponding to all of the candidates and selects the candidate with the highest probability as the final prediction. Finally, an optimized model update strategy is proposed to enable the multi-task observation model for the variation of the tracked cell over the entire tracking procedure. The performance and robustness of the proposed method are analyzed by comparing with other commonly-used methods. Experimental results demonstrate that the proposed method has good performance to the cell tracking problem

Data from: Comparison of chemical composition in the buds of Aralia elata from different geographical origins of China

Aralia elata buds contain many nutrients and have a pleasant taste with unique flavor. Previous studies mainly focused on triterpene saponins in the root bark of this species, but little information existed concerning other chemical components, especially in the buds. To better understand the nutritional value of Aralia elata, we compared total flavonoids, total saponins, phenolic compounds and mineral elements contents in the buds of Aralia elata collected from eight different geographical regions (S1: Benxi; S2: Linjiang; S3: Pingwu; S4: Enshi; S5: Changbaishan; S6: Shangzhi; S7: Xiaoxinganling and S8: Harbin) in China. The results showed that the basic composition in the buds presented a wide variation noticed by ash (8.76 to 10.35%), crude fiber (5.38 to 11.07%), polysaccharides (33.85 to 46.79 mg/g), total flavonoid content (4.06 to 48.63 mg/g) and total saponins (13.62 to 27.85 mg/g). UPLC combined with LC-MS/MS method was used for the phenolic compounds analysis, and eleven phenolic compounds were identified and quantified in the 8 samples. The total phenolic content in Enshi (S4) was significantly higher than others, and quercetin was the predominant phenolic compound in this sample. We used ICP-OES to identify and quantify nine mineral elements in the buds. The Fe and Cu contents in S5 were much higher than that of others. We got maximum Mg, Mn, Co and Ni contents in S4, and found rich Zn content in S7. Moreover, the maximum estimated quantity of Ca and Sr contents were found in S8. This study indicated that the chemical composition in the buds of Aralia elata was obviously affected by geographical origin. Our results provided an essential theoretical basis on quality evaluation of Aralia elata buds in food production field

Development and validation of a PCR-RFLP / TaqMan MGB probe method for rapid sex identification of largemouth bass (Micropterus salmoides)

The largemouth bass (Micropterus salmoides) has become an important freshwater fish in China since it was intentionally introduced in the 1980 s, and the amount produced in aquaculture is increasing each year. Females are preferred because they grow faster than males and reach a larger body size. However, the physiological sex cannot be accurately determined from external morphology at the early growth stage, so it is crucial to develop sex-specific molecular markers. In this study, a single nucleotide polymorphism (SNP) marker was developed based on whole genome resequencing data obtained from 30 females and 30 males. This marker made it possible to positively identify male and female largemouth bass. Through Fst value screening, 123 SNP loci significantly associated with sex were obtained, and nearly 40% of them were located on chromosome 7 in a 3.44-Mb sex-linked region. A method of polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) combined with a TaqMan minor groove binder (MGB) probe was developed based on a sex-specific marker. Using this method, male and female fish in four different populations (n = 128) were identified with 100% accuracy. Compared with PCR-RFLP followed by electrophoretic separation of fragments, the PCR-RFLP–TaqMan MGB probe method reduced the time required to identify the sex of largemouth bass. The validation results also indicated that largemouth bass has an XX/XY sex-determination system. In conclusion, we have identified a sex-specific SNP marker for largemouth bass and developed a new technique to identify the sex of largemouth bass rapidly and accurately. These findings provide a scientific basis for further research on mono-sex breeding and the molecular mechanism of sex determination in largemouth bass

Distribution of five vibrio virulence-related genes among Vibrio harveyi isolates

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Overexpression, Purification, Characterization, and Pathogenicity of Vibrio harveyi Hemolysin VHH

Vibrio harveyi VHH hemolysin is a putative pathogenicity factor in fish. In this study, the hemolysin gene vhhA was overexpressed in Escherichia coli, and the purified VHH was characterized with regard to pH and temperature profiles, phospholipase activity, cytotoxicity, pathogenicity to flounder, and the signal peptide

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A Single Residue Change in Vibrio harveyi Hemolysin Results in the Loss of Phospholipase and Hemolytic Activities and Pathogenicity for Turbot (Scophthalmus maximus)▿

Vibrio harveyi hemolysin, an important virulence determinant in fish pathogenesis, was further characterized, and the enzyme was identified as a phospholipase B by gas chromatography. Site-directed mutagenesis revealed that a specific residue, Ser153, was critical for its enzymatic activity and for its virulence in fish