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Low protein
About: Low protein is a research topic. Over the lifetime, 8139 publications have been published within this topic receiving 213225 citations.
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TL;DR: Interaction between diet fed and family was found close to significance for weight and relative growth rate, and significant for length and condition factor, indicating that prospects for selectively breeding strains of rainbow trout specifically better able to utilize protein are promising.
88 citations
TL;DR: A simple and extremely gentle method based upon isopycnic sucrose density gradient ultracentrifugation of treponemes following plasmolysis in 20% sucrose is described, which suggests that the poor antigenicity of virulent T. pallidum is a function of both the lipid composition and the low protein content of its OM.
Abstract: Previous freeze-fracture electron microscopy (EM) studies have shown that the outer membrane (OM) of Treponema pallidum contains sparse transmembrane proteins. One strategy for molecular characterization of these rare OM proteins involves isolation of T. pallidum OMs. Here we describe a simple and extremely gentle method for OM isolation based upon isopycnic sucrose density gradient ultracentrifugation of treponemes following plasmolysis in 20% sucrose. Evidence that T. pallidum OMs were isolated included (i) the extremely low protein/lipid ratio of the putative OM fraction, (ii) a paucity of antigenic and/or biochemical markers for periplasmic, cytoplasmic membrane, and cytosolic compartments, and (iii) freeze-fracture EM demonstrating that the putative OMs contained intramembranous particles highly similar in size and density to those in native T. pallidum OMs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that the OMs contained a relatively small number of treponemal proteins, including several which did not appear to correspond to previously characterized T. pallidum antigens. Interestingly, these candidate rare OM proteins reacted poorly with syphilitic sera as determined by both conventional immunoblotting and enhanced chemiluminescence. Compared with whole cells, T. pallidum OMs were deficient in cardiolipin, the major lipoidal antigen reactive with antibodies in syphilitic sera. Also noteworthy was that other lipoidal constituents of OMs, including the recently discovered glycolipids, did not react with human syphilitic sera. These latter observations suggest that the poor antigenicity of virulent T. pallidum is a function of both the lipid composition and the low protein content of its OM.
88 citations
TL;DR: It is found that at low protein solution concentrations, ppNIPAM-treated surfaces are low fouling below the LCST, but protein retentive above it, and the temperature dependent difference in protein activity as well as time-of-flight secondary ion mass spectrometry and principal component analysis study suggest that proteins take different conformations/orientations after adsorption on ppNipAM above and below theLCST.
Abstract: Thorough studies of protein interactions with stimulus responsive polymers are necessary to provide a better understanding of their applications in biosensors and biomaterials. In this study, protein behavior on a thermoresponsive polymer surface, plasma polymerized N-isopropyl acrylamide (ppNIPAM), is investigated using multiple characterization techniques above and below its lower critical solution temperature (LCST). Protein adsorption and binding affinity are probed using radiolabeled proteins. Protein activity is estimated by measuring the immunological activity of an antibody adsorbed onto ppNIPAM using surface plasmon resonance. Conformation/orientation of the proteins is probed by time-of-flight secondary ion mass spectrometry (TOF-SIMS) and principal component analysis (PCA) of the TOF-SIMS data. In this work, we find that at low protein solution concentrations, ppNIPAM-treated surfaces are low fouling below the LCST, but protein retentive above it. The protein adsorption isotherms demonstrate that apparent affinity between soluble protein molecules and the ppNIPAM surface are an order of magnitude lower at room temperature than at 37 °C. Although direct protein desorption is not observed in our study when the surface temperature drops below the LCST, the binding affinity of surface adsorbed protein with ppNIPAM is reduced, as judged by a detergent elution test. Furthermore, we demonstrated that proteins adsorbed onto ppNIPAM are functionally active, but the activity is better preserved at room temperature than 37 °C. The temperature dependent difference in protein activity as well as TOF-SIMS and PCA study suggest that proteins take different conformations/orientations after adsorption on ppNIPAM above and below the LCST.
88 citations
Journal Article•
TL;DR: Very potent botulinum toxin Types C and D can be produced in intussuscepted cellophane tubing immersed in nutrient medium and are up to 8000 times as efficient in eliciting immunity as conventionally prepared toxoids.
Abstract: Summary 1.Very potent botulinum toxin Types C and D can be produced in intussuscepted cellophane tubing immersed in nutrient medium. This “dialysate” toxin is 50 to 100 times as potent as toxins prepared in the conventional way. 2.The “dialysate” toxins contain 1/50th to 1/100th of the protein nitrogen per M.L.D., Lf, and L+dose contained in the best of the non-“dialysate” toxins. The M.L.D./mg protein nitrogen of type D “dialysate” toxin is approximately the same as that of pure Type A toxin. 3.Formol-toxoids prepared from these “dialysate” toxins are up to 8000 times as efficient in eliciting immunity as conventionally prepared toxoids. A striking feature of these easily prepared toxoids is their low protein content. A dose that will provoke a very high antibody response in cattle may contain as little as 0.001 mg protein nitrogen. 4.The method is very suitable for preparing botulinum formol-toxoids on a large scale. Much less labour and effort is required than is needed in the preparation of toxoids by conventional methods. 5.There is evidence that the method can be adapted to the preparation of other Clostridial toxins.
88 citations
TL;DR: DNA‐protein complexes formed in vitro with isolated DNA‐binding proteins from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius were analyzed by electron microscopy and two of the proteins formed specific structures after incubation with DNA.
Abstract: DNA-protein complexes formed in vitro with isolated DNA-binding proteins from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius were analyzed by electron microscopy. Two of the proteins (10a and 10b) formed specific structures after incubation with DNA. Protein 10a, at low protein concentrations, showed individual small spots on the DNA and at high concentrations evenly covered doublestranded DNA. Protein 10b showed three different types of regular structures: one with single-stranded and two with double-stranded DNA. Using double-stranded DNA, 10b first bound cooperatively to two strands forming long, plait-like structures only slightly shorter than respective free DNA. The complex consists of two right-handed, interwound fibers, with a helical pitch of 26 nm and a diameter of approximately 10-11 nm. At higher protein concentration than needed to package all DNA into the complex with two double-stranded DNAs, the two DNAs were separated again and a new structure was formed evenly covering only one DNA strand. Both structures showed no significant contraction of the length of the DNA covered in the complex. Nucleoprotein formed with single-stranded PhiX174 DNA had a diameter of approximately 11 nm and could form circles with a contour length of 0.5 mum.
88 citations