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101.
Since the initial report of the development of methodology to generate high-affinity digitalis-specific (digoxin) antibodies, these antibodies have proven extremely useful tools to monitor digoxin levels in digitalized patients and, as Fab fragments, to reverse toxic digoxin effects in life-threatening digoxin overdoses. These antibodies (both digoxin-specific and ouabain-specific) have been used extensively by investigators for the identification and characterization of putative endogenous digitalis-like factors. In this study, we used two well-characterized mouse anti-digoxin monoclonal antibodies (mAbs), designated 26-10 and 45-20, as binding templates with which to select short bacteriophage-displayed (pIII protein inserted) peptides that are capable of binding to these mAbs and mimicking the conformational structure of digoxin. Selective enrichment from two phage-displayed random peptide libraries enabled us to isolate and identify distinct 15 and 26 amino acid residue peptide inserts that bind with high avidity and idiotypic specificity to the selecting mAbs. Among these displayed inserts a subset was identified whose mAb binding is inhibited by digoxin and whose corresponding synthetic peptides inhibit phage binding. They, therefore, appear to bind at the mAbs digoxin-binding sites. These data provide the first clear evidence that short polypeptides can serve as surrogates for the low molecular mass hapten digoxin.  相似文献   
102.
secA is translationally regulated by the protein secretion proficiency state of the Escherichia coli cell. This regulation was explored by making signal sequence mutations in the gene upstream of secA, gene X, which promotes secA translational coupling. Gene X signal sequence mutants were constitutive for secA expression, while prlA alleles partially restored secA regulation. These results show that interaction of the pre-gene X protein with the translocon is required for proper secA regulation. Furthermore, gene X signal sequence mutations disrupted secA regulation only in the cis configuration. We propose that nascent pre-gene X protein interacts with the translocon during its secretion to constitute the secretion sensor.  相似文献   
103.
104.
BackgroundThe study was designed to investigate the probable mechanisms of anti-hyperglycemic activity of B. Vulgaris.ConclusionFindings of the present study clearly prove the role of Acetylcholine and GLP-1 in the Insulin secreting activity of B. Vulgaris. Increased glucose uptake in the skeletal muscles and subsequent glycogen synthesis may also play a part in the anti-hyperglycemic activity of B. Vulgaris.  相似文献   
105.
Low productivity of pilosae type lentils grown in South Asia is attributed to narrow genetic base of the released cultivars which results in susceptibility to biotic and abiotic stresses. For enhancement of productivity and production, broadening of genetic base is essentially required. The genetic base of released cultivars can be broadened by using diverse types including bold seeded and early maturing lentils from Mediterranean region and related wild species. Genetic diversity in eighty six accessions of three species of genus Lens was assessed based on twelve genomic and thirty one EST-SSR markers. The evaluated set of genotypes included diverse lentil varieties and advanced breeding lines from Indian programme, two early maturing ICARDA lines and five related wild subspecies/species endemic to the Mediterranean region. Genomic SSRs exhibited higher polymorphism in comparison to EST SSRs. GLLC 598 produced 5 alleles with highest gene diversity value of 0.80. Among the studied subspecies/species 43 SSRs detected maximum number of alleles in L. orientalis. Based on Nei’s genetic distance cultivated lentil L. culinaris subsp. culinaris was found to be close to its wild progenitor L. culinaris subsp. orientalis. The Prichard’s structure of 86 genotypes distinguished different subspecies/species. Higher variability was recorded among individuals within population than among populations.  相似文献   
106.
The membrane proximal external region (MPER) of the gp41 subunit of the HIV-1 envelope glycoprotein (Env) contains determinants for broadly neutralizing antibodies and has remained an important focus of vaccine design. However, creating an immunogen that elicits broadly neutralizing antibodies to this region has proven difficult in part due to the relative inaccessibility of the MPER in the native conformation of Env. Here, we describe the antigenicity and immunogenicity of a panel of oligomeric gp41 immunogens designed to model a fusion-intermediate conformation of Env in order to enhance MPER exposure in a relevant conformation. The immunogens contain segments of the gp41 N- and C-heptad repeats to mimic a trapped intermediate, followed by the MPER, with variations that include different N-heptad lengths, insertion of extra epitopes, and varying C-termini. These well-characterized immunogens were evaluated in two different immunization protocols involving gp41 and gp140 proteins, gp41 and gp160 DNA primes, and different immunization schedules and adjuvants. We found that the immunogens designed to reduce extension of helical structure into the MPER elicited the highest MPER antibody binding titers, but these antibodies lacked neutralizing activity. The gp41 protein immunogens also elicited higher MPER titers than the gp140 protein immunogen. In prime-boost studies, the best MPER responses were seen in the groups that received DNA priming with gp41 vectors followed by gp41 protein boosts. Finally, although titers to the entire protein immunogen were similar in the two immunization protocols, MPER-specific titers differed, suggesting that the immunization route, schedule, dose, or adjuvant may differentially influence MPER immunogenicity. These findings inform the design of future MPER immunogens and immunization protocols.  相似文献   
107.
In this paper, we have made a comparative evaluation of the cytotoxicity and pathophysiological effects of mainstream smoke from cellulose acetate (CA)-filtered cigarettes with that of charcoal-filtered cigarettes developed in our laboratory. Previously, we had demonstrated that the mainstream smoke from an Indian CA-filtered commercial cigarette contains p-benzosemiquinone (p-BSQ), a major, highly toxic, long-lived water-soluble radical. Here, we have examined 16 brands of different CA-filtered cigarettes including Kentucky research cigarettes, and observed that mainstream smoke from all the cigarettes contains substantial amounts of p-BSQ (100–200 μg/cigarette). We also show that when the CA filter is replaced by a charcoal filter, the amount of p-BSQ in the mainstream smoke is reduced by 73–80%, which is accompanied by a reduction of carbonyl formation in bovine serum albumin to the extent of 70–90%. The charcoal filter also prevented cytotoxicity in A549 cells as evidenced by MTT assay, apoptosis as evidenced by FACS analysis, TUNEL assay, overexpression of Bax, activation of p53 and caspase 3, as well as emphysematous lung damage in a guinea pig model as seen by histology and morphometric analysis. The results indicate that the charcoal filter developed in our laboratory may protect smokers from cigarette smoke-induced cytotoxity, protein modification, apoptosis and emphysema.  相似文献   
108.
Anti-bacterial drug resistance is one of the most critical concerns among the scientist worldwide. The novel antimicrobial decapeptide SD-8 is designed and its minimal inhibitory concentration and therapeutic index (TI) was found in the range of 1–8 μg/ml and 45–360, respectively, against major group of Gram positive pathogens (GPP). The peptide was also found to be least hemolytic at a concentration of 180 μg/ml, i.e., nearly 77 times higher than its average effective concentration. The kinetics assay showed that the killing time is 120 min for methicillin-sensitive Staphylococcus aureus (MSSA) and 90 min for methicillin-resistant S. aureus (MRSA). Membrane permeabilization is the cause of peptide antimicrobial activity as shown by the transmission electron microscopy studies. The peptide showed the anti-inflammatory property by inhibiting COX-2 with a K D and K i values of 2.36 × 10−9 and 4.8 × 10−8 M, respectively. The peptide was also found to be effective in vivo as derived from histopathological observations in a Staphylococcal skin infection rat model with MRSA as causative organism.  相似文献   
109.
Leishmaniasis is caused by the dimorphic protozoan parasite Leishmania. Differentiation of the insect form, promastigotes, to the vertebrate form, amastigotes, and survival inside the vertebrate host accompanies a drastic metabolic shift. We describe a gene first identified in amastigotes that is essential for survival inside the host. Gene expression analysis identified a 27 kDa protein‐encoding gene (Ldp27) that was more abundantly expressed in amastigotes and metacyclic promastigotes than in procyclic promastigotes. Immunofluorescence and biochemical analysis revealed that Ldp27 is a mitochondrial membrane protein. Co‐immunoprecipitation using antibodies to the cytochrome c oxidase (COX) complex, present in the inner mitochondrial membrane, placed the p27 protein in the COX complex. Ldp27 gene‐deleted parasites (Ldp27?/?) showed significantly less COX activity and ATP synthesis than wild type in intracellular amastigotes. Moreover, the Ldp27?/? parasites were less virulent both in human macrophages and in BALB/c mice. These results demonstrate that Ldp27 is an important component of an active COX complex enhancing oxidative phosphorylation specifically in infectious metacyclics and amastigotes and promoting parasite survival in the host. Thus, Ldp27 can be explored as a potential drug target and parasites devoid of the p27 gene could be considered as a live attenuated vaccine candidate against visceral leishmaniasis.  相似文献   
110.
The high sterol concentration in eukaryotic cell membranes is thought to influence membrane properties such as permeability, fluidity and microdomain formation. Drosophila cannot synthesize sterols, but do require them for development. Does this simply reflect a requirement for sterols in steroid hormone biosynthesis, or is bulk membrane sterol also essential in Drosophila? If the latter is true, how do they survive fluctuations in sterol availability and maintain membrane homeostasis? Here, we show that Drosophila require both bulk membrane sterol and steroid hormones in order to complete adult development. When sterol availability is restricted, Drosophila larvae modulate their growth to maintain membrane sterol levels within tight limits. When dietary sterol drops below a minimal threshold, larvae arrest growth and development in a reversible manner. Strikingly, membrane sterol levels in arrested larvae are dramatically reduced (dropping sixfold on average) in most tissues except the nervous system. Thus, sterols are dispensable for maintaining the basic membrane biophysical properties required for cell viability; these functions can be performed by non-sterol lipids when sterols are unavailable. However, bulk membrane sterol is likely to have essential functions in specific tissues during development. In tissues in which sterol levels drop, the overall level of sphingolipids increases and the proportion of different sphingolipid variants is altered. These changes allow survival, but not growth, when membrane sterol levels are low. This relationship between sterols and sphingolipids could be an ancient and conserved principle of membrane homeostasis.  相似文献   
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