Rate Kon Research Articles

Multicenter Survey on Phantom Entrance Surface Air Kerma of Angiography and IVR in Japan

In DRLs 2020, the entrance surface air kerma (Ka,e) was set to 17 mGy/min as the reference dose rate in fluoroscopy. But, Ka,e in fluoroscopy for different regions and Ka,e in exposure was not set. A multicenter survey was conducted to evaluate Ka,e by each area. Ka,e for each area was analyzed for 79 facilities attending this survey (274 machines and 461 protocols). When the protocols were changed by the difference in disease, angiography, or IVR, the difference rate of Ka,e was evaluated. Ka,e before and after modifying the incident air kerma at the patient entrance reference point (Ka,r) and air kerma area product (PKA) difference rate were calculated when protocols were changed, considering the DRLs 2020. There were dose differences in Ka,e by each area. Compared to DRLs 2020, 36 protocols from 13 facilities modified their protocols, all of which reduced Ka,e. Although reducing Ka,e does not necessarily reduce Ka,r, and PKA, comparison of Ka,e by each area is expected to optimize medical exposure protection, including evaluation of quality control.

Exponential Model for Adsorption Kinetics

Adsorption is one of the most widely applied techniques for the removal of contaminants from the environment. The effectiveness of an adsorbent is dependent on its kinetics. There are lots of studies on adsorption kinetics, and several mathematical models have been developed to describe this process based on certain perceived underlying mechanism. However, most models which have been used to fit the kinetic data have shown a moderate level of correlation or no fit at all. This is mainly because of error in assuming the governing equation and erroneous assumptions when finding solutions to the governing equations. In this research an exponential model is proposed. It is believed that adsorption of an adsorbate onto an adsorbent follows essentially two stages. There is a rapid stage that tends towards a first phase pseudo-equilibrium (Qr(0)) at a rate of kr and transits at a time ‘tr’ and rate ktr to a slow stage which tends towards a second phase pseudo-equilibrium (Qs(0)) at a rate of ka which marks the climax of the process. Mathematical equations were used to describe this process and solved analytically to obtain the new exponential model. The model was used to estimate kinetic data and compared with the first and second order equations with an R2 of 0.994, 0.999 and 0.998 respectively. The new adsorption parameters Qr(0) , Qs(0), kr, ks, ktr and tr were also extracted from the calibrated model.

Protective Effects of Two Safflower Derived Compounds, Kaempferol and Hydroxysafflor Yellow A, on Hyperglycaemic Stress-Induced Podocyte Apoptosis via Modulating of Macrophage M1/M2 Polarization.

Objective The primary initiating mechanism in diabetes nephropathy (DN) is hyperglycemia-induced inflammation in which macrophage and podocyte play important roles. The present research is aimed at exploring the effects of kaempferol (Ka) and hydroxysafflor yellow A (HSYA) on classically activated (M1)/alternatively activated (M2) macrophage polarization and podocyte apoptosis under hyperglycaemic conditions in vitro. Methods (1) RAW264.7 cells were treated with 11.1 mM glucose (NG), 33.3 mM glucose (HG), Ka 4–8 μM, and HSYA 100–200 μM separately. The expressions of inducible nitric oxide synthase (iNOS), tumor necrosis factor- (TNF-) α, mannose receptor (CD206), and arginase- (Arg-) 1 were quantified by Western blotting and real-time quantitative PCR. The collected supernatants from macrophage were named as (NG) MS, (HG) MS, (Ka) MS, and (HSYA) MS. (2) The podocyte survival rate was assessed by Bromodeoxyuridine assay, while TNF-α and interleukin- (IL-) 1β levels were evaluated by Elisa. Results (1) Compared to the HG group, the Ka and HSYA 100 μM groups decreased iNOS and TNF-α levels and increased Arg-1 and CD206 expressions significantly (protein and mRNA: p < 0.05, respectively). (2) The podocyte survival rate of Ka 8 μM was higher than that of HG, and the rates of (Ka) MS and (HSYA 100 μM) MS were higher than that of (HG) MS significantly (all: p < 0.05). (3) TNF-α and IL-1β levels of Ka and HSYA 100 μM were significantly lower than those of the HG group, and both levels in the (Ka) MS and (HSYA) MS were lower than those in the (HG) MS group significantly (p < 0.05, respectively). Conclusion The protective effects of Ka and HSYA on podocyte apoptosis under hyperglycemic stress are related to their modulation on M1/M2 polarization and the lowering effects on TNF-α and IL-1β levels.

Korovkin type approximation theorem via Ka−convergence on weighted spaces

In this paper, we study the Korovkin type approximation theorem for Ka‐ convergence, which is an interesting convergence method on weighted spaces. We also study the rate of Ka−convergence by using the weighted modulus of continuity and afterwards, we present a nontrivial application.

Affinity capture surface carboxyl-functionalized MoS2 sheets to enhance the sensitivity of surface plasmon resonance immunosensors

The development of functionalized molybdenum disulfide (MoS2) has led to a new trend in the biosensing field, owing to its high sensitivity and bio-affinity characteristics with regards to the simple synthesis of carboxyl-functionalized MoS2 nanocomposites. In this study, we used monochloroacetic acid (MCA) to successfully modify carboxyl-MoS2. The efficiency of this MCA modification method showed a higher -COOH group content of 30.1%, mainly due to chlorine atoms occupying the MoS2 sulfur vacancy to allow for the formation of a strong bonding effect. This then enhanced the surface area of -COOH and improved the formation of covalent bonds between proteins. We demonstrated that MoS2-COOH-based surface plasmon resonance (SPR) chips can provide excellent sensitivity and high affinity for immunoassay biomolecules detected in a low sample volume of 20 μl. With respect to the shifts of the SPR angles of the chips, the high binding affinity at a BSA concentration of 14.5 nM for a MoS2-COOH chip, a MoS2 chip and a traditional SPR chip are 4.69 m°, 2.49 m° and 1.53 m°, respectively. In addition, the MoS2-COOH chip could amplify the SPR angle response by 3.1 folds and enhance the high association rate of ka by 212 folds compared to MoS2 and traditional SPR chips. The results thus obtained revealed that the overall affinity binding value, KA, of the MoS2-COOH chip can be significantly enhanced by up to ∼ 6.5 folds that of the MoS2 chip. In summary, the excellent binding affinity, biocompatible and high sensitivity suggest the potential of the clinical application of this MoS2-COOH-based SPR chip detection method for in vitro diagnostic and point-of-care testing devices.

Evolutionary and biogeographical implications of degraded LAGLIDADG endonuclease functionality and group I intron occurrence in stony corals (Scleractinia) and mushroom corals (Corallimorpharia).

Group I introns and homing endonuclease genes (HEGs) are mobile genetic elements, capable of invading target sequences in intron-less genomes. LAGLIDADG HEGs are the largest family of endonucleases, playing a key role in the mobility of group I introns in a process known as ‘homing’. Group I introns and HEGs are rare in metazoans, and can be mainly found inserted in the COXI gene of some sponges and cnidarians, including stony corals (Scleractinia) and mushroom corals (Corallimorpharia). Vertical and horizontal intron transfer mechanisms have been proposed as explanations for intron occurrence in cnidarians. However, the central role of LAGLIDADG motifs in intron mobility mechanisms remains poorly understood. To resolve questions regarding the evolutionary origin and distribution of group I introns and HEGs in Scleractinia and Corallimorpharia, we examined intron/HEGs sequences within a comprehensive phylogenetic framework. Analyses of LAGLIDADG motif conservation showed a high degree of degradation in complex Scleractinia and Corallimorpharia. Moreover, the two motifs lack the respective acidic residues necessary for metal-ion binding and catalysis, potentially impairing horizontal intron mobility. In contrast, both motifs are highly conserved within robust Scleractinia, indicating a fully functional endonuclease capable of promoting horizontal intron transference. A higher rate of non-synonymous substitutions (Ka) detected in the HEGs of complex Scleractinia and Corallimorpharia suggests degradation of the HEG, whereas lower Ka rates in robust Scleractinia are consistent with a scenario of purifying selection. Molecular-clock analyses and ancestral inference of intron type indicated an earlier intron insertion in complex Scleractinia and Corallimorpharia in comparison to robust Scleractinia. These findings suggest that the lack of horizontal intron transfers in the former two groups is related to an age-dependent degradation of the endonuclease activity. Moreover, they also explain the peculiar geographical patterns of introns in stony and mushroom corals.

The complete mitochondrial genome of the ridgetail white prawn Exopalaemon carinicauda Holthuis, 1950 (Crustacean: Decapoda: Palaemonidae) revealed a novel rearrangement of tRNA genes

The complete mitochondrial (mt) DNA sequence was determined for a ridgetail white prawn, Exopalaemon carinicauda Holthuis, 1950 (Crustacea: Decopoda: Palaemonidae). The mt genome is 15,730 bp in length, encoding a standard set of 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes, which is typical for metazoans. The majority-strand consists of 33.6% A, 23.0% C, 13.4% G, and 30.0% T bases (AT skew = 0.057; GC skew = − 0.264). A total of 1045 bp of non-coding nucleotides were observed in 16 intergenic regions, including a major A + T rich (79.7%) noncoding region (886 bp). A novel translocation of tRNA Pro and tRNA Thr was found when comparing this genome with the pancrustacean ground pattern indicating that gene order is not conserved among caridean mitochondria. Furthermore, the rate of Ka/ Ks in 13 protein-coding genes between three caridean species is much less than 1, which indicates a strong purifying selection within this group. To investigate the phylogenetic relationship within Malacostraca, phylogenetic trees based on currently available malacostracan complete mitochondrial sequences were built with the maximum likelihood and Bayesian models. All analyses based on nucleotide and amino acid data strongly support the monophyly of Decapoda. The Penaeidae, Reptantia, Caridea, and Meiura clades were also recovered as monophyletic groups with strong statistical support. However, the phylogenetic relationships within Pleocyemata are unstable, as represented by the inclusion or exclusion of Caridea.

Affinity measurements of biological molecules by a quartz crystal microbalance (QCM) biosensor.

We present a immunosensing system based on a quartz crystal microbalance (QCM) that allows detection and evaluation of a broad range of molecules relevant to medicine and biology. Soluble analyte is applied by injection into a flow-through chamber where receptor molecules are immobilized, thus enabling real-time measurement of the specific intermolecular interactions. This system can be used for detection purposes, e.g., screening for antibodies, and for determination of affinity constants including affinity evaluation of newly selected or designed aptamers, as kd and ka rates can be derived from the sensograms.

Effect of &lt;FONT FACE=Symbol&gt;b&lt;/font&gt;-D-xylosides bearing different aglycones on the synthesis of proteoglycans during the cell cycle of endothelial cells in culture

SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).

Structure and transcription of genes encoding the surface glycoprotein antigens gp90 and gp82 of Trypanosoma cruzi metacyclic trypomastigotes

SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).

Cell damage and neurogenesis in the dentate granule cell layer of adult rats after pilocarpine- or kainate-induced status epilepticus

Dentate granule cells are generally considered to be relatively resistant to excitotoxicity and have been associated with robust synaptogenesis after neuronal damage. Synaptic reorganization of dentate granule cell axons, the mossy fibers, has been suggested to be relevant for hyperexcitability in human temporal lobe epilepsy and animal models. A recent hypothesis suggested that mossy-fiber sprouting is dependent on newly formed dentate granule cells. However, we recently demonstrated that cycloheximide (CHX) can block the mossy-fiber sprouting that would otherwise be induced by different epileptogenic agents and does not interfere with epileptogenesis in those models. Here, we investigated cell damage and neurogenesis in the dentate gyrus of pilocarpine- or kainate-treated animals with or without coadministration of CHX. Dentate granule cells were highly vulnerable to pilocarpine induced-status epilepticus (SE), but were hardly damaged by kainate-induced SE. CHX pretreatment markedly reduced the number of injured neurons after pilocarpine-induced SE. Induction of SE dramatically increased the mitotic rate of KA- and KA + CHX-treated animals. Induction of SE in animals injected with pilocarpine alone led to 2-7-fold increases in the mitotic rate of dentate granule cells as compared to 5- and 30-fold increases for pilocarpine + CHX animals. We suggest that such increased mitotic rates might be associated with a protection of a vulnerable precursor cell population that would otherwise degenerate after pilocarpine-induced SE. We further suggest that mossy-fiber sprouting and neurogenesis of granule cells are not necessarily linked to one another.

Synthesis and immunological activity of a branched peptide construction carrying the T cell epitope of Paracoccidioides brasiliensis major exocellular antigen, the gp43

SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).

Comparison of the human immune responses to recombinant proteins representing three distinct surface proteins of Plasmodium vivax merozoites

SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).

Competitive antagonism associated with blockade of neuronal uptake: effects of indoramine in rat vas deferens and aorta

SUMMARY OF COMMUNICATIONS CELL DAMAGE AND NEUROGENESIS IN THEDENTATE GRANULE CELL LAYER OF ADULT RATSAFTER PILOCARPINE- OR KAINATE-INDUCEDSTATUS EPILEPTICUS CovolanL.,RibeiroL.T.C.,LongoB.M.andMelloL.E.A.M. Department of Physiology, UNIFESP, 04023-900 Sao Paulo,SP.Presented by A.C.M.Paiva Dentate granule cells are generally considered to berelatively resistant to excitotoxicity and have been asso-ciated to robust synaptogenesis after neuronal damage.Synaptic reorganization of dentate granule cell axons,the mossy fibers, has been suggested to be relevant forhyperexcitability in human temporal lobe epilepsy andanimal models. A recent hypothesis has suggested thatmossy fiber sprouting is dependent on newly formed den-tate granule cells. However, we have recently demon-strated that cycloheximide (CHX) can block the mossyfiber sprouting that would be otherwise induced by dif-ferent epileptogenic agents and do not interfere withepileptogenesis in those models. Here, we investigatedcell damage and neurogenesis in the dentate gyrus ofpilocarpine- or kainate-treated animals with or withoutthe co-administration of CHX. Dentate granule cells werehighly vulnerable to pilocarpine induced-status epilep-ticus (SE), but hardly damaged by kainate induced-SE.CHX-pretreatment markedly reduced the number of in-jured neurons after pilocarpine-induced SE. Induction ofSE dramatically increased the mitotic rate of KA and KA+ CHX treated animals. Induction of SE in animals in-jected with pilocarpine alone led to increases of betweentwo to sevenfold in the mitotic rate of dentate granulecells as compared to increases of between five and thirty-fold for pilocarpine+CHX animals. These observationsindicate that in presence of cycloheximide the increase ofthe mitotic rate after pilocarpine-induced SE may be duetoprotectionofavulnerableprecursorcellpopulationthatwould otherwise degenerate. We further suggest that themossy fiber sprouting and neurogenesis of granule cellsare not necessarily related events. — ( September 14,1999 ).

Cell damage and neurogenesis in the dentate granule cell layer of adult rats after pilocarpine- or kainate-induced status epilepticus.

Dentate granule cells are generally considered to be relatively resistant to excitotoxicity and have been associated with robust synaptogenesis after neuronal damage. Synaptic reorganization of dentate granule cell axons, the mossy fibers, has been suggested to be relevant for hyperexcitability in human temporal lobe epilepsy and animal models. A recent hypothesis suggested that mossy-fiber sprouting is dependent on newly formed dentate granule cells. However, we recently demonstrated that cycloheximide (CHX) can block the mossy-fiber sprouting that would otherwise be induced by different epileptogenic agents and does not interfere with epileptogenesis in those models. Here, we investigated cell damage and neurogenesis in the dentate gyrus of pilocarpine- or kainate-treated animals with or without coadministration of CHX. Dentate granule cells were highly vulnerable to pilocarpine induced-status epilepticus (SE), but were hardly damaged by kainate-induced SE. CHX pretreatment markedly reduced the number of injured neurons after pilocarpine-induced SE. Induction of SE dramatically increased the mitotic rate of KA- and KA + CHX-treated animals. Induction of SE in animals injected with pilocarpine alone led to 2-7-fold increases in the mitotic rate of dentate granule cells as compared to 5- and 30-fold increases for pilocarpine + CHX animals. We suggest that such increased mitotic rates might be associated with a protection of a vulnerable precursor cell population that would otherwise degenerate after pilocarpine-induced SE. We further suggest that mossy-fiber sprouting and neurogenesis of granule cells are not necessarily linked to one another.

The CryIA(c) Receptor Purified from Manduca sexta Displays Multiple Specificities

The kinetic binding characteristics of four Bacillus thuringiensis CryI insecticidal crystal proteins to a Cry-binding protein, purified from Manduca sexta brush-border vesicles, were analyzed by an optical biosensor. This 120-kilodalton binding protein, previously determined to be aminopeptidase N, was converted to a 115-kilodalton water-soluble form by removing the attached glycosylphosphatidylinositol anchor with phospholipase C. The solubilized form recognized the three major subclasses of CryIA toxins but not CryIC even though all four CryI proteins are toxic to larvae of M. sexta. CryIA(a) and CryIA(b) toxins bound to a single site on the solubilized aminopeptidase N molecule whereas CryIA(c) bound to two distinct sites. Apparent kinetic rate constants were determined for each binding reaction. All three CryIA toxins exhibited moderately fast on rates (approximately 10(-5) M-1 s-1) and a slow reversible off rate (approximately 10(-3) s-1). Although the second CryIA(c)-binding site retained a moderately fast association rate, it was characterized by a rate of dissociation from the amino-peptidase an order of magnitude faster than observed for the other CryIA-binding sites. CryIA(c) binding to both sites was strongly inhibited in the presence of N-acetylgalactosamine (IC50 = 5 mM) but not N-acetylglucosamine, mannose, or glucose. CryIA(a) and CryIA(b) binding were unaffected in the presence of the same sugars. Our results serve to illustrate both the complexity and the diverse nature of toxin interactions with Cry-binding proteins.

Radikalpolymerisation von methylmethacrylat im gesamten umsatzbereich. Stationäre und instationäre experimente zur bestimmung von wachstums‐ und abbruchsgeschwindigkeit

AbstractFree‐radical polymerization of methyl methacrylate in bulk at 0°C over the full range of conversion is reported. Details for stationary and non‐stationary experiments are described allowing to measure both kinetically relevant ratios fk/ka and kw/ka, f representing radical efficiency, kw rate constants of propagation and ka rate constant of termination. From these ratios the absolute rate constants kw and ka are available. The photochemical decay of the initiator 1,1′‐azodicyclohexanenitrile in connection with the rotating‐sector technique and observation of the post‐effect after stopping the initiator decay were used. The rate of polymerization and the number‐ and weight‐average molar masses were measured. Both, kw and ka, showed a strong dependence on conversion which is well known for ka but is reported here for the first time for kw since Hayden and Melville's determination of kw from measurements of the temperature increase during polymerization were reported.