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Polyethylene glycol modification (PEGylation) is a widely used strategy to improve the physicochemical properties of various macromolecules, especially protein drugs. However, its application in enhancing the performance of enzymes for molecular biology remains underexplored. This study explored the PEGylation of Bst DNA polymerase, determining optimal modification reaction conditions. In comparison to the unmodified wild-type counterpart, the modified Bst DNA polymerase exhibited significantly improved activity, thermal stability, and inhibitor tolerance during loop-mediated isothermal amplification. When applied for the detection of Salmonella in crude samples, the modified enzyme demonstrated a notably accelerated reaction rate. Therefore, PEGylation emerges as a viable strategy for refining DNA polymerases, helping in the development of novel molecular diagnostic reagents. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is a widespread protozoan parasite that infects most warm-blooded animals, and felids can serve as intermediate and definitive hosts. Pathological diagnosis and serological and etiological investigations were conducted on a captive caracal (Caracal caracal) carcass collected from China in 2022. Pathological diagnosis revealed that cardiac insufficiency, pulmonary edema, hepatic failure, and renal insufficiency were the causes of the caracal's death. A modified agglutination test (cut-off: 1:25) revealed that IgG antibodies against T. gondii were present in the myocardium juice (1:1600), ascitic fluid (1:3200), and hydropericardium (1:800). A viable T. gondii (TgCaracalCHn2) strain was isolated from the tissue samples (heart, brain, spleen, and skeletal muscle) of this caracal using a mouse bioassay. The genotype of TgCaracalCHn2 was ToxoDB#5 (Type II variant), as determined via RFLP-PCR. The strain was avirulent in Swiss mice and matched the prediction of ROP18 and ROP5 gene alleles of TgCaracalCHn2 (2/2). Mild tissue cysts (203 ± 265) were observed in mice brains after inoculation with TgCaracalCHn2 tachyzoites. ToxoDB#5 is the dominant genotype in North American wildlife, and this is the first documented isolation of T. gondii ToxoDB#5 from China. This indicates that caracal plays an important role in the transmission of this T. gondii genotype. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low recognition accuracy, poor edge recognition effect and slow extraction speed in current remote sensing image crop extraction, a remote sensing image crop segmentation method based on improved DeepLabV3+ network is proposed. The feature extraction network is changed to a lighter MobileNetV2 network, and the ordinary convolution in the atrous spatial pyramid pooling module is changed to deep separable convolution, which greatly reduces the amount of model calculation and improves the calculation speed of the model. The double attention mechanism is added to the feature extraction module and the atrous spatial pyramid pooling module to further optimize the effect of model edge recognition and improve the accuracy of model segmentation. In addition, aiming at the imbalance of crop data sets, the weighted loss function is introduced to give different weights to corn, job's tears and background classes, so as to improve the accuracy of crop region segmentation. Taking the UAV remote sensing image of an area in 2019 as the research object, corn and job's tears are segmented. The experimental results show that the pixel accuracy of the improved DeepLabV3+ algorithm can reach 93.9%, the average recall can reach 90.7%, and the average intersection and merging ratio can reach 83.3%, which is better than the traditional segmentation methods commonly used for crop extraction, such as DeepLabV3+, Unet, Segnet and it has better segmentation effect on crops. [ABSTRACT FROM AUTHOR]