Complex formation of potassium salt of highly fatty acid with hemagglutinin protein in influenza virus via exothermic interaction

In our previous study, we found highly fatty acid salts, which are a skin-friendly soaps, had a high ability to inactivate the influenza virus. In order to elucidate the mechanism of inactivation of influenza virus, we investigated interactions and complex formation of potassium tetradecanoate (C14K) as a highly fatty acid salt with a virus particle (VP) derived from avian influenza virus by using isothermal titration calorimetry (ITC) and small-angle X-ray scattering (SAXS). ITC showed C14K attractively interacted with hemagglutinin protein (HA) which exists in the envelop of VP. SAXS analyses revealed C14K formed highly ordered complex with HA through the attractive interaction. Since the HA is responsible for cell entry events, inactivation of influenza viruses by highly fatty acid salts are derived owing to HA inhibition of influenza viruses through the complex formation. Time-resolved SAXS measurements elucidated the complex formation was completed within 40 s after mixing aqueous solutions of C14K and VP. This result strongly suggests that hand-washing with a highly fatty acid salts is an effective measure to prevent infection with influenza virus without causing rough hands.     

Enhanced formation of isoamyl alcohol in Zygosaccharomyces rouxii due to elimination of feedback inhibition of α-isopropylmalate synthase

Abstract Mutants of the 'miso' yeast, Zygosaccharomyces rouxii , that produced a large amount of isoamyl alcohol, an important flavour in miso fermentation, were isolated from 5,5,5-trifluoro-dl-leucine-resistant mutants, an analogue of l-leucine. One of the mutants, M21-10, produced a three-fold higher level of isoamyl alcohol than the wild-type strain MY21 in miso fermentation. The activity of α-isopropylmalate synthase, one of the enzymes used for l-leucine synthesis, in the mutant M21-10 was not inhibited by the addition of l-leucine, a feedback inhibitor.     

Parental origin and mechanism of formation of polysomy X: an XXXXX case and four XXXXY cases determined with RFLPs

Summary The parental origin and mechanism of formation of polysomy X were studied in five cases (one case of 49,XXXXX; four cases of 49,XXXXY), using various X-linked restriction fragment length polymorphisms as genetic markers. Segregation and densitometric analyses on the polymorphic DNA fragments revealed that, in all five cases, the additional X chromosomes are of maternal origin and the mechanism of formation is most probably a result of three non-disjunctions during maternal meiotic divisions: once at the first meiosis and simultaneously twice at the second meiosis. The identical origin and the identical mechanism of formation among the five cases are unlikely to be coincidental and suggest a common cause in the mothers of the five cases.     

Genetic and Molecular Analysis of Wild-Derived Arrhythmic Mice

A new circadian variant was isolated by screening the intercross offspring of wild-caught mice (Mus musculus castaneus). This variant was characterized by an initial maintenance of damped oscillations and subsequent loss of rhythmicity after being transferred from light-dark (LD) cycles to constant darkness (DD). To map the genes responsible for the persistence of rhythmicity (circadian ratio) and the length of free-running period (τ), quantitative trait locus (QTL) analysis was performed using F₂ mice obtained from an F₁ cross between the circadian variant and C57BL/6J mice. As a result, a significant QTL with a main effect for circadian ratio (Arrhythmicity; Arrh-1) was mapped on Chromosome (Chr) 8. For τ, four significant QTLs, Short free-running period (Sfp-1) (Chr 1), Sfp-2 (Chr 6), Sfp-3 (Chr 8), Sfp-4 (Chr 11) were determined. An epistatic interaction was detected between Chr 3 (Arrh-2) and Chr 5 (Arrh-3). An in situ hybridization study of clock genes and mouse Period1::luciferase (mPer1::luc) real-time monitoring analysis in the suprachiasmatic nucleus (SCN) suggested that arrhythmicity in this variant might not be attributed to core circadian mechanisms in the SCN neurons. Our strategy using wild-derived variant mice may provide a novel opportunity to evaluate circadian and its related disorders in human that arise from the interaction between multiple variant genes.     

The protein encoded by NCgl1221 in Corynebacterium glutamicum functions as a mechanosensitive channel

The function of the NCgl1221-encoded protein of Corynebacterium glutamicum was analyzed using Bacillus subtilis as host because a method for preparing the giant provacuole required for electrophysiological studies has been established. Expression of NCgl1221 in a strain deficient in mscL and ykuT, both of which encode mechanosensitive channels, resulted in an 8.9-fold higher cell survival rate upon osmotic downshock than the control. Electrophysiological investigation showed that the giant provacuole prepared from this strain, expressing NCgl1221, exhibited significantly higher pressure-dependent conductance than the control. These findings show that the NCgl1221-encoded protein functions as a mechanosensitive channel.     

Differences in larval dynamics of golden mussel <Emphasis Type="Italic">Limnoperna fortunei</Emphasis> between dam reservoirs with and without an aeration system

The golden mussel Limnoperna fortunei is a freshwater bivalve that adheres to water intake facilities, leading to problems of several kinds. Biofouling problems have been increasing recently in East Asia and South America, and the planktonic stage of this species is considered to play an important role in its dispersal. We investigated the larval dynamics of L. fortunei in two reservoirs, Lake Ohshio and Lake Takenuma, which are connected by a headrace channel. An aeration system for water quality conservation was present in the former reservoir but not in the latter. Larval density in Lake Ohshio was more than 10,000 individuals/m³ with a maximum of 80,000 individuals/m³ in summer. The density in Lake Takenuma was much lower, with a maximum of around 200 individuals/m³. Water temperature (WT) and dissolved oxygen (DO) concentration were almost uniform regardless of water depth in Lake Ohshio because of destratification due to continuous aeration. Summer WT and DO in the lake were considered to be suitable for survival and reproduction of L. fortunei. On the other hand, stratification was found for WT and DO in Lake Takenuma throughout the summer. The low WT and DO found in the deep areas of the lake in summer were considered to be not suitable for survival and reproduction of this species. Thus, the population of L. fortunei larvae differed widely even in two adjoining lakes, and WT and DO are considered to be critical factors, especially for reproduction.     

Contribution of ferrous iron to maintenance of the gastric colonization of Helicobacter pylori in miniature pigs

Our previous study showed that the colonization levels of Helicobacter pylori were higher in the stomachs of 5-day-old miniature pigs than in 2-week-old ones. As dietary factors can cause these differences, we compared two diets, i.e., Weanymilk and a similar formula with a higher concentration of Fe(II), Weanylobulin. The colonization levels in the fundic mucosa were significantly higher in 2-week-old pigs fed Weanylobulin than in those fed Weanymilk. Supplementing Weanylobulin with an iron chelator, deferoxamine mesylate, significantly lowered the bacteria counts in the gastric mucosa. Normal diets supplemented with Fe(II) in 2-month-old pigs caused significantly more sites of bacteria in the antrum compared with normal diets alone. In addition, ranitidine, an inhibitor of gastric acid secretion that reduces Fe(III) to Fe(II) in the stomach, decreased the bacteria counts in 10-month-old pigs. These results suggested that Fe(II) maintained the colonization levels of H. pylori in the stomach of the miniature pigs.     

Mutational analysis on the function of the SWAP-70 PH domain

Hepatocellular carcinoma (HCC), the major manifestation of primary liver cancer, is one of the most frequent and malignant cancers worldwide, especially in Taiwan. Estrogen receptors (ERs) have been reported to play either a proliferation- or apoptosis-enhancing role in the differentiation of cancers, including HCC. In a previous experiment, we showed that transient overexpressed estrogen receptor-α induced early stage HCC cell line Hep 3B cell apoptosis by increasing the hTNF-α gene expression in a ligand-independent manner. To further clarify if the apoptotic effect occurs in poorly differentiated HCC cell line, HA22T, and elucidate the roles of ERs and TNF-α, DNA fragmentation and caspase activity were measured in late stage HCC cell line, HA22T, by measuring the expression of hER-α and hER-β using a Tetracycline-induciable system (Tet-on). Increased DNA fragmentation and caspase-3 activity were found in hERβ-overexpressed HA22T cells treated with estrogen (10⁻⁸ M) but not in hERα-overexpressed HA22T cells. Using RT-PCR/PCR and western blotting in HA22T cells, overexpressed hER-β was also found to increase the expression of hTNF-α mRNA and induce hTNF-α-dependent luciferase activity in a ligand-dependent manner. Additionally, LPS treatment and hER-β overexpression both enhance caspase-8 activities, whereas neither hER-β nor E₂ treatment affected caspase-9 activities. In addition, the overexpressed hER-β plus E₂ enhanced DNA fragmentation and caspase-8 activities were only partially reduced by anti-hTNF-α (0.1ng/ml), which was possibly due to the involvement of P53 and TGF-β. Taken together, our data indicates that overexpressed hER-β but not hER-α may induce caspase-8-mediated apoptosis by increasing the hTNF-α gene expression in a ligand-dependent manner in poorly differentiated HA22T cells. (Mol Cell Biochem xxx: 1–9, 2005)Shares equally contribution Contract grant sponsor: National Science Council; Contract grant number: NSC 91-2314-B-075A-006, NSC 92-2314-B-075A-014.     

Different sensitivities to agonist of muscarinic acetylcholine receptor subtypes

Muscarinic acetylcholine receptor (mAChR) III expressed in Xenopus oocytes, like mAChR I, mediates activation of a Ca²⁺-dependent Cl⁻ current, whereas mAChR IV, like mAChR II, principally induces activation of Na⁺ and K⁺ currents in a Ca²⁺-independent manner. mAChR III has a sensitivity to agonist of about one order of magnitude higher than that of mAChR I in mediating the Ca²⁺-dependent current response in Xenopus oocytes and in stimulating phosphoinositide hydrolysis in NG108-15 neuroblastoma-glioma hybrid cells. The agonist-binding affinity of mAChR III is also about one order of magnitude higher than that of mAChR I.     

Purification and characterization of alpha 1-thiol proteinase inhibitor and its identity with kinin- and fragment 1.2-free high molecular weight kininogen

1. alpha 1-Thiol proteinase inhibitor (alpha 1 TPI) purified from outdated human plasma was a glycoprotein with Mr 83,000 and was composed of heavy and light chains held together with a disulfide bond. 2. The data on amino acid composition, amino terminal sequence of the light chain and carboxyl terminal sequences of the heavy and light chains indicate that alpha 1 TPI is identical with kinin- and fragment 1.2-free HMW kininogen. 3. Purified human plasmin generated a derivative having the same molecular weight (Mr 83,000), same subunit structure (heavy and light chains) and same inhibitory capacity as alpha 1 TPI from HMW kininogen and kinin-free HMW kininogen. This indicated the possibility that alpha 1 TPI is derived from HMW kininogen by plasmin.