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Yutaro Yamagata Yukiko Muramoto Sho Miyamoto Keiko Shindo Masahiro Nakano Takeshi Noda 《Microbiology and immunology》2019,63(5):164-171
Defective interfering (DI) influenza viruses carry a large deletion in a gene segment that interferes with the replication of infectious virus; thus, such viruses have potential for antiviral therapy. However, because DI viruses cannot replicate autonomously without the aid of an infectious helper virus, clonal DI virus stocks that are not contaminated with helper virus have not yet been generated. To overcome this problem, we used reverse genetics to generate a clonal DI virus with a PB2 DI gene, amplified the clonal DI virus using a cell line stably expressing the PB2 protein, and confirmed its ability to interfere with infectious virus replication in vitro. Thus, our approach is suitable for obtaining purely clonal DI viruses, will contribute to the understanding of DI virus interference mechanisms and can be used to develop DI virus‐based antivirals. 相似文献
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J J Beintema J Hofsteenge M Iwama T Morita K Ohgi M Irie R H Sugiyama G L Schieven C A Dekker D G Glitz 《Biochemistry》1988,27(12):4530-4538
The amino acid sequence of a nonsecretory ribonuclease isolated from human urine was determined except for the identity of the residue at position 7. Sequence information indicates that the ribonucleases of human liver and spleen and an eosinophil-derived neurotoxin are identical or very closely related gene products. The sequence is identical at about 30% of the amino acid positions with those of all of the secreted mammalian ribonucleases for which information is available. Identical residues include active-site residues histidine-12, histidine-119, and lysine-41, other residues known to be important for substrate binding and catalytic activity, and all eight half-cystine residues common to these enzymes. Major differences include a deletion of six residues in the (so-called) S-peptide loop, insertions of two, and nine residues, respectively, in three other external loops of the molecule, and an addition of three residues at the amino terminus. The sequence shows the human nonsecretory ribonuclease to belong to the same ribonuclease superfamily as the mammalian secretory ribonucleases, turtle pancreatic ribonuclease, and human angiogenin. Sequence data suggest that a gene duplication occurred in an ancient vertebrate ancestor; one branch led to the nonsecretory ribonuclease, while the other branch led to a second duplication, with one line leading to the secretory ribonucleases (in mammals) and the second line leading to pancreatic ribonuclease in turtle and an angiogenic factor in mammals (human angiogenin). The nonsecretory ribonuclease has five short carbohydrate chains attached via asparagine residues at the surface of the molecule; these chains may have been shortened by exoglycosidase action.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Martin Bundi Mohammad Monir Shah Eric Odoyo Cyrus Kathiiko Ernest Wandera Gabriel Miring'u Sora Guyo Daniel Langat Kouichi Morita Yoshio Ichinose 《Microbiology and immunology》2019,63(9):350-358
Kenya is endemic for cholera with different waves of outbreaks having been documented since 1971. In recent years, new variants of Vibrio cholerae O1 have emerged and have replaced most of the traditional El Tor biotype globally. These strains also appear to have increased virulence, and it is important to describe and document their phenotypic and genotypic traits. This study characterized 146 V. cholerae O1 isolates from cholera outbreaks that occurred in Kenya between 1975 and 2017. Our study reports that the 1975–1984 strains had typical classical or El Tor biotype characters. New variants of V. cholerae O1 having traits of both classical and El Tor biotypes were observed from 2007 with all strains isolated between 2015 and 2017 being sensitive to polymyxin B and carrying both classical and El Tor type ctxB. All strains were resistant to Phage IV and harbored rstR, rtxC, hlyA, rtxA and tcpA genes specific for El Tor biotype indicating that the strains had an El Tor backbone. Pulsed field gel electrophoresis (PFGE) genotyping differentiated the isolates into 14 pulsotypes. The clustering also corresponded with the year of isolation signifying that the cholera outbreaks occurred as separate waves of different genetic fingerprints exhibiting different genotypic and phenotypic characteristics. The emergence and prevalence of V. cholerae O1 strains carrying El Tor type and classical type ctxB in Kenya are reported. These strains have replaced the typical El Tor biotype in Kenya and are potentially more virulent and easily transmitted within the population. 相似文献
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An examination of four species of Cirsium disclosed the presence of two new flavonoids in C. lineare. The structure of one was 5,4′-dihydroxy-6,7,3′-trimethoxyflavone (cirsilineol) 4′-monoglucoside and the other 5,3′,4′-trihydroxy-6,7-dimethoxyflavone (cirsiliol) 4′-monoglucoside. Luteolin 7-glucoside was found in C. suffultum, and pectolinarin and linarin in C. kamtschaticum and C. pectinellum. 相似文献
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Although patients with primary hyperparathyroidism (1 degree HPT) were euthyroid, we measured serum thyroid hormone levels in 16 patients with 1 degree HPT together with 17 patients with hypercalcemia due to malignant diseases (HCM). In patients with 1 degree HPT, serum levels of T3, T4 and T3U were within normal range, but serum rT3 (reverse T3) levels (205 +/- 37 pg/ml, mean +/- SD) were significantly decreased as compared with those in normal controls (276 +/- 44 pg/ml, P less than 0.01). A significant inverse correlation was observed between the serum levels of rT3 and parathyroid hormone (PTH) (r = 0.54, P less than 0.05). After parathyroidectomy, serum rT3 levels were significantly elevated (240 +/- 56 pg/ml) compared to preoperative levels (P less than 0.01). Low levels of serum rT3 seemed to be attributed to the high levels of serum PTH. On the other hand, serum levels of T3 and T4 were low and serum rT3 levels were high in patients with HCM. Low serum rT3 allows for the differentiation of patients with 1 degree HPT from those with HCM. 相似文献
10.
Shun-Ichiro Kawabata Takashi Morita Toshiyuki Miyata Shigenori Kaida Sadaaki Iwanaga Hideo Igarashi 《Journal of Protein Chemistry》1987,6(1):17-32
The bacterial protein staphylocoagulase binds stoichiometrically to human prothrombin, resulting in a coagulant complex, staphylothrombin. The enzymatic properties of staphylothrombin differ from those of -thrombin in their substrate specificities toward natural and synthetic substrates, in addition to their interaction with protease inhibitors. In order to obtain information about the region of staphylocoagulase that interacts with human prothrombin, staphylocoagulase was cleaved by -chymotrypsin. Limited -chymotryptic cleavage of staphylocoagulase yielded three large fragments, of 43, 30, and 20 kD. The 43-kD fragment exhibited a high affinity for human prothrombin (Kd=1.7 nM), which is comparable to the affinity observed using intact staphylocoagulase (Kd=0.46 nM). A complex of the 43-kD fragment and prothrombin possessed both clotting and amidase activity essentially identical to that observed in a complex of intact staphylocoagulase and prothrombin. The 30-kD fragment exhibited weaker affinity for prothrombin (Kd=120 nM.) While clotting activity was not observed with a complex of this fragment and prothrombin, it nonetheless possessed a weak amidase activity. The 20-kD fragment was found only to bind to prothrombin. The NH2-terminal sequence analyses of these fragments revealed that the 43-kD fragment constitutes the NH2-terminal portion of staphylocoagulase, and contains the 30-kD and 20-kD fragments. It is therefore concluded that the functional region of staphylocoagulase for binding and activation of prothrombin is localized in the NH2-terminal region of the intact protein. The 43-kD fragment contained 324 amino acids with a molecular weight of 38,098. The 43-kD fragment had an unusual amino acid composition based on a sequence in which the sum of Asp (28 residues), Asn (22), Glu (35), Gln (9), and Lys (52) residues accounted for more than 45% of the total. A comparison of the amino acid sequence of the 43-kD fragment with that of streptokinase did not reveal any obvious sequence homology. There was also no sequence homology with that of trypsin, -chymotrypsin, and elastase.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985. 相似文献