Computational Multiple Steady States of the Penicillin G Acylase‐Catalyzed Hydrolysis in an Isothermal CFSTR

A family of an enzymatically catalyzed reaction network was studied, which involves the hydrolysis of penicillin G by penicillin G acylase in an isothermal continuous flow stirred tank reactor (CFSTR). This system consisted of 10 coupled non‐linear equations and was found to be capable of exhibiting computational multiple steady states. A set of kinetic parameters determined from the existing experimental data were used to compute a set of rate constants and two corresponding steady states. This suggested that multiple steady states may occur in the system studied. The phenomena of bistability, hysteresis and bifurcation were discussed. Moreover, the capacity of steady state multiplicity was extended to its family of reaction networks.     

Maitotoxin Induces Phosphoinositide Turnover and Modulates Glutamatergic and Muscarinic Cholinergic Receptor Function in Cultured Cerebellar Neurons

Maitotoxin (MTX) stimulated inositol phosphate (IP) formation in primary cultures of rat cerebellar granule cells. MTX-induced IP production was dependent on extracellular Ca2+ but independent of extracellular Na+. The stimulation of IP formation elicited by MTX was unaffected by pretreatment of cells with phorbol dibutyrate, pertussis toxin, and a variety of Ca2+ entry blockers, such as nimodipine, nisoldipine, Co2+, and Mn2+. The presence of MTX markedly attenuated IP production induced by carbachol and glutamate, with no apparent effect on the responses to norepinephrine (NE), histamine, 5-hydroxytryptamine (5-HT), and endothelin-1. The inhibition of the carbachol- and glutamate-induced responses by MTX was dose dependent with IC50 values of 1.2 and 0.5 ng/ml, respectively. Pretreatment of cells with a lower concentration of MTX (0.3 ng/ml) also attenuated carbachol- and glutamate-induced IP formation, in a time-dependent manner, with a decrease observed after 30 min prestimulation, but failed to affect NE-, histamine-, 5-HT-, endothelin-1, and sarafotoxin S6b-induced responses. Thus, MTX elicited a marked Ca2(+)-dependent phosphoinositide (PI) turnover in cerebellar granule cells and selectively inhibited carbachol- and glutamate-induced PI hydrolysis. Possible mechanisms underlying these selective modulations are discussed.     

Head-to-Head Comparison between Collagen Proportionate Area and Acoustic Radiation Force Impulse Elastography in Liver Fibrosis Quantification in Chronic Hepatitis C

BackgroundThe aim of this study was to compare the diagnostic performances of the collagen proportionate area (CPA) and liver stiffness measurement (LSM) for liver fibrosis quantification in chronic hepatitis C (CHC).MethodsA total of 137 eligible consecutive Taiwanese patients (74 women and 63 men; age 21–80 years; median age 54 years), with CHC underwent LSM by using acoustic radiation force impulse (ARFI) elastography and an immediate percutaneous liver biopsy for METAVIR scoring. Liver tissue sections were stained using picrosirius red. Areas of the stained collagen and the tissue parenchyma were calculated in pixels. The ratio between the two areas was expressed as a CPA percentage. The result of LSM was presented as shear wave velocity (SWV).ResultsMETAVIR fibrosis (F) stages were dichotomized using the CPA (%) and SWV (m/s), and the optimal cut-off values were 7.47 and 1.59 for F1 versus F2–4; 12.56 and 1.73 for F1, 2 versus F3, 4; 15.32 and 1.96 for F1–3 versus F4. To dichotomize F1 versus F2–4, the areas under receiver operating characteristic curves for the CPA was 0.9349 (95% confidence interval: 0.8943–0.9755) and for SWV was 0.8434 (0.7762–0.9105) (CPA versus SWV, P = 0.0063). For F1, 2 versus F3, 4, the CPA was 0.9436 (0.9091–0.9781); SWV was 0.8997 (0.8444–0.9551) (P = 0.1587). For F1–3 versus F4, the CPA was 0.8647 (0.7944–0.9349); SWV was 0.9036 (0.8499–0.9573) (P = 0.2585). The CPA could be predicted in a linear regression formula by using SWV and platelet count (R² = 0.524).ConclusionsThe CPA and ARFI elastography are promising tools for liver fibrosis evaluation. The CPA was superior to ARFI elastography in the diagnosis of significant fibrosis (≥ F2). The CPA may be independent of severe necroinflammation, which may augment liver stiffness.     

Rapid identification of the north-western Pacific billfish species using quantitative real-time polymerase chain reaction techniques

Billfishes are important fishery resources traded and consumed worldwide. As morphological traits are usually removed during processing, molecular methods are applied to identify billfish products. In this study, the approaches of quantitative real-time PCR were developed to identify the six billfish species (Istiompax indica, Istiophorus platypterus, Kajikia audax, Makaira nigricans, Tetrapturus angustirostris and Xiphias gladius) widely distributed in the north-western Pacific Ocean. The developed singleplex systems showed high fidelities to each of the six species via either examining the ΔCt values or melting curve patterns. For samples containing multiple species, individual species are identifiable by a quantitative real-time PCR assay that includes all the singleplex systems. A multiplex system was also developed to identify unknown samples composed of a single species. The methods developed in this study provide a fast and high-throughput manner to identify the north-western Pacific billfish species when morphological traits are unavailable, such as in processed products.     

Differential Regulation by Butyrate and Dibutyryl Cyclic AMP of δ-Opioid, α2-Adrenergic, and Muscarinic Cholinergic Receptors in NCB-20 Cells

Long-term treatment of NCB-20 cells with sodium butyrate resulted in a marked increase in the specific binding of [3H]D-Ala2,D-Leu5 enkephalin. This increase was concentration and time dependent, with an EC50 of about 480 microM and a maximal effect detected after 3-day treatment. At saturating concentration of butyrate (1 mM) the increase was three- to fourfold of the untreated control. Scatchard analysis revealed that the butyrate effect was due to an increase in the density of the opioid receptor binding sites. Butyrate also induced a smaller (about twofold) increase in the density of muscarinic cholinergic receptor binding assessed by using [3H]quinuclidinyl benzilate, whereas alpha 2-adrenergic receptor binding assessed by using [3H]clonidine was not significantly affected. The butyrate-induced opioid receptor binding could be totally abolished by the presence of cycloheximide, suggesting that the butyrate effect involves synthesis of the receptor protein. Butyrate treatment did not affect basal and prostaglandin E1-stimulated cyclic AMP levels but caused a three- to fourfold decrease in the IC50 of D-Ala2,D-Leu5 enkephalin for attenuating these cyclic AMP levels and approximately 25% increase in the maximal extent of attenuation. In contrast to the butyrate effect, long-term treatment of NCB-20 cells with 1 mM dibutyryl cyclic AMP induced an 80% decrease in the opioid and alpha 2-adrenergic receptor bindings and a 57% loss of muscarinic cholinergic receptor binding. This down-regulation of muscarinic cholinergic receptor binding sites was associated with a 35% decrease of carbachol-induced phosphoinositide breakdown, whereas the receptor up-regulation induced by butyrate was found to increase the carbachol response by about threefold. The differential regulation by butyrate and dibutyryl cyclic AMP suggests that the butyrate effect is mediated by a mechanism independent of intracellular cyclic AMP. The induction by butyrate of opioid-receptors and muscarinic cholinergic receptors in NCB-20 cells may provide a useful system for studying the regulation of gene expression of these receptor proteins.     

Substrates for protein kinase C in a cell free preparation of rat aorta smooth muscles

Protein phosphorylation has been studied in a cell free system of rat aorta smooth muscles. Addition of Ca2+ caused phosphorylation of several proteins. The addition of phosphatidylserine or calmodulin together with Ca2+ further increased the phosphorylation of proteins with apparent molecular weights of 20 and 92.5 kilodaltons. The activators of protein kinase C, 12-0-tetradecanoylphorbol-13-acetate and 1,2-diolein, increased phosphorylation of the protein bands of similar molecular weight to those increased by phosphatidylserine in the presence of Ca2+, whereas the biologically inactive phorbol ester, 4 alpha-phorbol-12,13 didecanoate (4 alpha PDD) failed to change the pattern of protein phosphorylation. These results show that proteins present in smooth muscle of rat aorta with molecular weights of 20 and 92.5 kilodaltons are substrates for protein kinase C.     

The Species and Origin of Shark Fins in Taiwan’s Fishing Ports,Markets, and Customs Detention: A DNA Barcoding Analysis

The increasing consumption of shark products, along with the shark’s fishing vulnerabilities, has led to the decrease in certain shark populations. In this study we used a DNA barcoding method to identify the species of shark landings at fishing ports, shark fin products in retail stores, and shark fins detained by Taiwan customs. In total we identified 23, 24, and 14 species from 231 fishing landings, 316 fin products, and 113 detained shark fins, respectively. All the three sample sources were dominated by Prionace glauca, which accounted for more than 30% of the collected samples. Over 60% of the species identified in the fin products also appeared in the port landings, suggesting the domestic-dominance of shark fin products in Taiwan. However, international trade also contributes a certain proportion of the fin product markets, as four species identified from the shark fin products are not found in Taiwan’s waters, and some domestic-available species were also found in the customs-detained sample. In addition to the species identification, we also found geographical differentiation in the cox1 gene of the common thresher sharks (Alopias vulpinus), the pelagic thresher shark (A. pelagicus), the smooth hammerhead shark (Sphyrna zygaena), and the scalloped hammerhead shark (S. lewini). This result might allow fishing authorities to more effectively trace the origins as well as enforce the management and conservation of these sharks.     

Neuromuscular abnormality and autonomic dysfunction in patients with cerebrotendinous xanthomatosis

Background  

Cerebrotendinous xanthomatosis (CTX) is a rare lipid-storage disease. Neuromuscular abnormality and autonomic system (ANS) dysfuction in CTX are rarely examined in large-scale studies in the literature. We studied the peripheral nervous system, myopathology, and autonomic system of four CTX patients and performed a literature review of the reported CTX patients with peripheral neuropathy.