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1.
Zhang J Tanha J Hirama T Khieu NH To R Tong-Sevinc H Stone E Brisson JR MacKenzie CR 《Journal of molecular biology》2004,335(1):49-56
We describe a novel type of molecule in which single-domain antibodies (sdAbs) isolated from a nai;ve llama single domain antibody library are linked to an oligomerization domain to generate high-avidity, antigen-binding reagents. An sdAb is fused to the B-subunit of Escherichia coli verotoxin, or shiga-like toxin, which self-assembles to form a homopentamer and results in simultaneous sdAb pentamerization and introduction of avidity. Molecular modeling indicated that this fusion protein (PDB: 1OJF), termed pentabody, has structural flexibility for binding to surface-presented antigen. In the instance of an sdAb specific for a peptide antigen, pentamerization resulted in a dramatic increase in functional affinity for immobilized antigen. The pentabody was expressed in high yield in E.coli in a non-aggregated state, and exhibited excellent thermostability and protease resistance. This technology provides a relatively rapid means of generating novel antigen-binding molecules that bind strongly to immobilized antigen. It is expected that pentavalent sdAbs will have general applicability in proteomics, immunochemical staining, cancer diagnosis and other applications in which antigens are presented multivalently. 相似文献
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Teymouri Babak Ghiasi Ghalehkandi Jamshid Hassanpour Shahin Aghdam-Shahryar Habib 《International journal of peptide research and therapeutics》2020,26(1):381-387
International Journal of Peptide Research and Therapeutics - The aim of the current study was to determine effect of in ovo feeding of vitamin B12 on hatchability, growth performance and blood... 相似文献
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Maryam Pakfetrat Jamshid Roozbeh Shahroodi Ali Asgar Zolgadr Hasan Amin Larie Mohamad Hosein Nikoo Leila Malekmakan 《Biological trace element research》2013,153(1-3):11-15
Increased homocysteine (hCys) level is an independent risk factor for cardiovascular complications in end-stage renal disease (ESRD) patients. The aim of this study was to evaluate effect of zinc (Zn) supplement on serum hCys level in ESRD patients. One hundred ESRD patients with Zn deficiency were enrolled in this double-blind randomized clinical trial. They were randomly subdivided into two groups and supplemented with Zn (Zn group) or placebo (control group) for 6 weeks. Fasting plasma hCys and Zn levels were measured before and at 43rd days after the start of the study. Serum Zn levels increased significantly (p?<?0.0001), in Zn-treated group in comparison to placebo-treated group. In the Zn-treated group, serum hCys levels reduced significantly (p?<?0.0001), compared to placebo group (p?>?0.05). There was a significant (p?<?0.0001) reduction of mean percentage of hCys in Zn-treated group compared to the placebo group. Our study showed that Zn supplementation decreases serum hCys levels in ESRD patients with Zn deficiency. 相似文献
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A sensitive fluorescent nanosensor for chloramphenicol based on molecularly imprinted polymer‐capped CdTe quantum dots
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A novel fluorescent nanosensor using molecularly imprinted silica nanospheres embedded CdTe quantum dots (CdTe@SiO2@MIP) was developed for detection and quantification of chloramphenicol (CAP). The imprinted sensor was prepared by synthesis of molecularly imprinting polymer (MIP) on the hydrophilic CdTe quantum dots via reverse microemulsion method using small amounts of solvents. The resulting CdTe@SiO2@MIP nanoparticles were characterized by fluorescence, UV–vis absorption and FT‐IR spectroscopy and transmission electron microscopy. They preserved 48% of fluorescence quantum yield of the parent quantum dots. CAP remarkably quenched the fluorescence of prepared CdTe@SiO2@MIP, probably via electron transfer mechanism. Under the optimal conditions, the relative fluorescence intensity of CdTe@SiO2@MIP decreased with increasing CAP by a Stern–Volmer type equation in the concentration range of 40–500 µg L–1. The corresponding detection limit was 5.0 µg L–1. The intra‐day and inter‐day values for the precision of the proposed method were all <4%. The developed sensor had a good selectivity and was applied to determine CAP in spiked human and bovine serum and milk samples with satisfactory results. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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The ability of the wild-type XIAP BIR3 domain as well as its Trp323Ser variant in inhibition of human caspase-9, binding to AVPFVASLPN (SMAC-peptide), SMAC protein, and mature caspase-9 was investigated. In order to investigate the role of W323 on these interactions, this residue was mutated to Serine. Circular dichroism as well as thermal denaturation studies showed that W323S mutation did not hamper proper folding of the protein. The dissociation constants for the interaction of the wild type BIR3 as well as its mutant to Smac-type peptide were found to be 1.8 and 27 muM, respectively. The inhibition of and binding to caspase-9 by wild-type BIR3 and its mutant were also compared. While the wild-type protein potently inhibited the enzyme, the mutant failed to do so. The lack of caspase-9 inhibition was due to absence of interaction of the mutant BIR3 with mature caspase-9. These results indicate that Trp323 of BIR3 plays a pivotal role both in maintaining necessary conformation for caspase-9 interaction and to a lesser extent, recognition of Smac-type peptide. Moreover, decreased stability of the mutant compared with the wild type indicates that W323 is essential for maintaining the stability BIR3-Smac-peptide complex. 相似文献
7.
DNA extraction and PCR amplification method suitable for fresh, herbarium-stored, lichenized, and other fungi 总被引:6,自引:0,他引:6
Oscar F. Cubero Ana Crespo Jamshid Fatehi Paul D. Bridge 《Plant Systematics and Evolution》1999,216(3-4):243-249
This paper presents a DNA extraction method suitable for fresh, herbarium-stored, lichenized and other fungal specimens. The method is fast and reliable, comparatively inexpensive and is suitable for obtaining PCR amplification quality DNA from large numbers of samples in a short time. The method has been tested with over 300 samples ofAscochyta, Phyllosticta, Ramalina, Parmelia andPhysconia. Amplifiable fungal DNA was extracted from pure cultures, leaf lesions, whole thalli and dissected only-fungal sections of lichenized fungi. In addition, the method has proved suitable for use with herbarium specimens of both lichenized and non-lichenized fungi, stored as dried pure cultures or dried infected plant material. 相似文献
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Caveolin-1 null mice develop cardiac hypertrophy with hyperactivation of p42/44 MAP kinase in cardiac fibroblasts 总被引:14,自引:0,他引:14
Cohen AW Park DS Woodman SE Williams TM Chandra M Shirani J Pereira de Souza A Kitsis RN Russell RG Weiss LM Tang B Jelicks LA Factor SM Shtutin V Tanowitz HB Lisanti MP 《American journal of physiology. Cell physiology》2003,284(2):C457-C474
Recently, development ofa caveolin-1-deficient (Cav-1 null) mouse model has allowed thedetailed analysis of caveolin-1's function in the context of awhole animal. Interestingly, we now report that the hearts ofCav-1 null mice are markedly abnormal, despite the fact that caveolin-1is not expressed in cardiac myocytes. However, caveolin-1 is abundantlyexpressed in the nonmyocytic cells of the heart, i.e., cardiacfibroblasts and endothelia. Quantitative imaging studies of Cav-1 nullhearts demonstrate a significantly enlarged right ventricular cavityand a thickened left ventricular wall with decreased systolic function.Histological analysis reveals myocyte hypertrophy withinterstitial/perivascular fibrosis. Because caveolin-1 is thought toact as a negative regulator of the p42/44 MAP kinase cascade, weperformed Western blot analysis with phospho-specific antibodies thatonly recognize activated ERK1/2. As predicted, the p42/44 MAP kinasecascade is hyperactivated in Cav-1 null heart tissue (i.e.,interstitial fibrotic lesions) and isolated cardiac fibroblasts. Inaddition, endothelial and inducible nitric oxide synthase levels aredramatically upregulated. Thus loss of caveolin-1 expression drivesp42/44 MAP kinase activation and cardiac hypertrophy. 相似文献
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Caveolin-1 null (-/-) mice show dramatic reductions in life span 总被引:7,自引:0,他引:7
Park DS Cohen AW Frank PG Razani B Lee H Williams TM Chandra M Shirani J De Souza AP Tang B Jelicks LA Factor SM Weiss LM Tanowitz HB Lisanti MP 《Biochemistry》2003,42(51):15124-15131
Caveolae are 50-100 nm flask-shaped invaginations of the plasma membrane found in most cell types. Caveolin-1 is the principal protein component of caveolae membranes in nonmuscle cells. The recent development of Cav-1-deficient mice has allowed investigators to study the in vivo functional role of caveolae in the context of a whole animal model, as these mice lack morphologically detectable caveolae membrane domains. Surprisingly, Cav-1 null mice are both viable and fertile. However, it remains unknown whether loss of caveolin-1 significantly affects the overall life span of these animals. To quantitatively determine whether loss of Cav-1 gene expression confers any survival disadvantages with increasing age, we generated a large cohort of mice (n = 180), consisting of Cav-1 wild-type (+/+) (n = 53), Cav-1 heterozygous (+/-) (n = 70), and Cav-1 knockout (-/-) (n = 57) animals, and monitored their long-term survival over a 2 year period. Here, we show that Cav-1 null (-/-) mice exhibit an approximately 50% reduction in life span, with major declines in viability occurring between 27 and 65 weeks of age. However, Cav-1 heterozygous (+/-) mice did not show any changes in long-term survival, indicating that loss of both Cav-1 alleles is required to mediate a reduction in life span. Mechanistically, these dramatic reductions in life span appear to be secondary to a combination of pulmonary fibrosis, pulmonary hypertension, and cardiac hypertrophy in Cav-1 null mice. Taken together, our results provide the first demonstration that loss of Cav-1 gene expression and caveolae organelles dramatically affects the long-term survival of an organism. In addition, aged Cav-1 null mice may provide a new animal model to study the pathogenesis and treatment of progressive hypertrophic cardiomyopathy and sudden cardiac death syndrome. 相似文献
10.
Chandra M Tanowitz HB Petkova SB Huang H Weiss LM Wittner M Factor SM Shtutin V Jelicks LA Chan J Shirani J 《International journal for parasitology》2002,32(7):897-905
Chagas' disease, caused by Trypanosoma cruzi, is associated with myocarditis and expression of myocardial cytokines and inducible nitric oxide synthase (NOS2). To assess the functional significance of NOS2 in murine Chagas' disease, we infected NOS2 knockout (NOS2(-/-)) and C57BL/6x129sv (wild type) mice with the Tulahuen strain of T. cruzi. Serial transthoracic echocardiography was performed to assess the progression of left and right ventricular dysfunction in infected mice. Uninfected wild type and NOS2(-/-) mice served as controls. At day 10 post-infection (p.i.), infected wild type mice had larger left ventricular end-diastolic diameter (2.52+/-0.14-vs-2.11+/-0.06 mm, P<0.02) and right ventricle (0.6+/-0.2-vs-0 visual grade, P<0.02) as compared with uninfected wild type mice. At day 19 p.i., compared with uninfected controls, infected wild type mice had larger left ventricular end-diastolic diameter (3.30+/-0.29-vs-2.11+/-0.07 mm), left ventricular end-systolic diameter (1.86+/-0.29-vs-0.88+/-0.05 mm), right ventricle (1.6+/-0.2-vs-0 visual grade), lower heart rate (413+/-27-vs-557+/-25 beats per min), left ventricular relative wall thickness (0.44+/-0.05-vs-0.64+/-0.03) and fractional shortening (45+/-4-vs-57+/-2%) [P<0.05 for all]. In contrast, no differences in left ventricular end-diastolic diameter or fractional shortening were noted among infected and uninfected NOS2(-/-) mice at day 19 p.i. Compared with uninfected controls, infected NOS2(-/-) mice had significantly lower heart rate (272+/-23-vs-512+/-31 beats per min, P<0.01) and larger right ventricle (0.6+/-0.2-vs-0, P<0.05 visual grade). The magnitude of right ventricular dilation in NOS2(-/-) mice was less than that observed in infected wild type mice. At necropsy, the heart weight was greater (129+/-16-vs-109+/-7 mg, P=0.02) and myocardial inflammation more severe in infected wild type compared with infected NOS2(-/-) mice. Myocardial interleukin (IL)-1beta, IL-6, tumour necrosis factor-alpha, and interferon-gamma were induced in all infected mice. These data indicate that nitric oxide derived from NOS2 plays an important role in the development and progression of ventricular dilation and systolic dysfunction in acute murine chagasic myocarditis caused by infection with the Tulahuen strain. 相似文献