Truncated versions of the human cytomegalovirus (CMV) strain Towne glycoprotein B (gB) gene were stably expressed in CHO cell lines. The calcium-specific ionophore A23187 inhibited proteolytic cleavage of C-terminal-truncated gB expressed by cell line 67.77. These inhibition studies also showed that the 93-kilodalton cleavage product most likely represents the N-terminal cleavage fragment of gB. The ionophore carboxyl cyanide m-chlorophenyl-hydrazone was used to show that proteolytic cleavage of gB did not occur in the endoplasmic reticulum. Two-dimensional polyacrylamide gel electrophoresis demonstrated that the N-and C-terminal cleavage products of gB remained associated by disulfide linkages after cleavage. Expression studies using constructs in which 80% or all of the N terminus was deleted demonstrated that the N terminus was required for secretion of the gB molecule. The amino acid sequence at the site of cleavage was shown to be critical for cleavage by a cellular protease. Our results indicate that an arginine-to-threonine change at either amino acid 457 or 460, a lysine-to-glutamine change at amino acid 459, or all three substitutions together block gB cleavage. The effect on proteolysis of the arginine-to-threonine amino acid change at residue 457 (position-4 relative to the cleavage site) demonstrated that a basic pair of amino acids at the endoproteolytic processing site is not the only requirement in cis for gB cleavage.

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In recent decades, image segmentation has aroused great interest of many researchers, and has become an important part of machine learning, pattern recognition, and computer vision. Among many methods of image segmentation, fuzzy C-means (FCM) algorithm is undoubtedly a milestone in unsupervised method. With the further study of FCM, various different kinds of FCM algorithms are put forward to deal with the specific problems in image segmentation. Because there exist uncertainties in different regions of the image and similarity in the same region, reducing the uncertainty is still the main problem in image segmentation. Considering that Pythagorean fuzzy set (PFS) is a powerful tool to deal with uncertainty, in this paper, we use PFS to describe the uncertainty of image segmentation, including introducing fuzzification and defuzzification process and Pythagorean fuzzy element to describe the membership degree of pixel, combine the neighborhood information with weights and Pythagorean fuzzy distance, and propose Pythagorean fuzzy C-means (PFCM) algorithm. Finally, we apply PFCM algorithm in image segmentation, such as different size images and Berkeley Segmentation Data Set to illustrate the effectiveness and applicability of our proposed algorithm. Meanwhile, we do comparison analysis between PFCM, fully convolution network

During the period of major epidemic prevention and control, cities and villages were closed one after another across the country, grid closed management was started, and the people started their home life mode. Schools actively respond to the relevant deployment of "stop classes and teaching, stop classes and school", and the youth sports activities also return to the family. Research shows that: home life, limited space, sports can change people's way of life; enhance physical fitness, anti-epidemic control. Under the epidemic situation, we should change the way of life through sports activities, optimize the family environment, adhere to exercise, and improve the immunity of teenagers and their family members, so as to prevent the epidemic situation. The advantages of sports lie in timely changing roles, stimulating vitality, strengthening heart and body, serving residents and contributing to society. It is also the historical mission and social obligation given to sports in a specific period and special stage to highlight the social responsibility and responsibility of sports in the context of epidemic situation.