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181.
Membrane trafficking intermediates involved in the transport of proteins between the TGN and the lysosome-like vacuole in the yeast Saccharomyces cerevisiae can be accumulated in various vps mutants. Loss of function of Vps45p, an Sec1p-like protein required for the fusion of Golgi-derived transport vesicles with the prevacuolar/endosomal compartment (PVC), results in an accumulation of post-Golgi transport vesicles. Similarly, loss of VPS27 function results in an accumulation of the PVC since this gene is required for traffic out of this compartment. The vacuolar ATPase subunit Vph1p transits to the vacuole in the Golgi-derived transport vesicles, as defined by mutations in VPS45, and through the PVC, as defined by mutations in VPS27. In this study we demonstrate that, whereas VPS45 and VPS27 are required for the vacuolar delivery of several membrane proteins, the vacuolar membrane protein alkaline phosphatase (ALP) reaches its final destination without the function of these two genes. Using a series of ALP derivatives, we find that the information to specify the entry of ALP into this alternative pathway to the vacuole is contained within its cytosolic tail, in the 13 residues adjacent to the transmembrane domain, and loss of this sorting determinant results in a protein that follows the VPS-dependent pathway to the vacuole. Using a combination of immunofluorescence localization and pulse/chase immunoprecipitation analysis, we demonstrate that, in addition to ALP, the vacuolar syntaxin Vam3p also follows this VPS45/27-independent pathway to the vacuole. In addition, the function of Vam3p is required for membrane traffic along the VPS-independent pathway. 相似文献
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183.
Binding of soy phosphatidylcholine (PC) and phosphatidylinositol (PI) with β-cyclodextrin (βCD) was studied using a spread
monolayer technique at the air–water interface. First, surface pressure (π) versus surface concentration (Γ) isotherms of
both PC and PI were characterized by forming spread monolayers on an aqueous subphase. PC and PI monolayers reached saturation
at Γ of 1.98 and 3.24 μmol/m2, respectively, at 25 °C. Subsequently, desorption of PC or PI from the spread monolayer in the presence of 2–14 mM βCD in
the subphase was studied by measuring changes in π of monolayer. This desorption was indicative of a complex formation between
βCD and PC or PI. The amount of PC or PI bound to βCD was determined by converting the net change in π to Γ by using π–Γ isotherms.
From the saturated monolayers at the air water-interface, approximately 30% of PC and 50% of PI could be removed by 14 mM
βCD. It was calculated that the free energy change required to transfer a PL from the monolayer at air–water interface to
the aqueous phase in presence of βCD was decreased by 6–7 kcal/mol. Hydrolysis of PC in the monolayer by phospholipase A2 (PLA2) improved extraction efficiency of βCD. By incorporating 2.29 μM PLA2 and 10 mM βCD in subphase, up to 80% of PC monolayer could be desorbed from the air–water interface. These results are discussed
in terms of the potential use of βCD to remove PLs bound to soy protein. 相似文献
184.
PURPOSE: We identified the incidence and types of genital and urinary anomalies, and established a plan for evaluating the urinary system in the CHARGE association. MATERIALS AND METHODS: We retrospectively reviewed the charts of 32 patients in whom the CHARGE association was diagnosed. RESULTS: Of the 32 patients identified 22 (69%) had genitourinary abnormalities. Genital anomalies, including micropenis, penile agenesis, hypospadias, chordee, cryptorchidism, a bifid scrotum, atresia of the uterus, cervix and vagina, and hypoplastic labia majora, labia minora and clitoris, were present in 18 patients (56%). Of the 24 patients who underwent renal ultrasound 10 (42%) were diagnosed with urinary tract anomalies including a solitary kidney, hydronephrosis, renal hypoplasia and duplex kidneys. Further evaluation revealed vesicoureteral reflux, neurogenic bladder secondary to spinal dysraphism, nephrolithiasis, ureteropelvic junction obstruction and a nonfunctioning upper pole in both duplex kidneys. CONCLUSIONS: There is a high incidence of genitourinary anomalies in the CHARGE association. Because of this high incidence of anomalies, patients with this condition should undergo a careful genitourinary evaluation, including renal and bladder ultrasound, and voiding cystourethrography screening. 相似文献
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188.
Diuron in both, acute (340 and 170 mg/kg body wt) and chronic (3400 ppm) doses induced dominant lethal mutations in male Swiss albino mice. The results suggest that diuron is mutagenic in dominant lethal test system. 相似文献
189.
P Wheelan JA Hankin B Bilir D Guenette RC Murphy 《Canadian Metallurgical Quarterly》1999,288(1):326-334
Analytic expressions for plasma total titratable base, base excess (DeltaCB), strong-ion difference, change in strong-ion difference (DeltaSID), change in Van Slyke standard bicarbonate (DeltaVSSB), anion gap, and change in anion gap are derived as a function of pH, total buffer ion concentration, and conditional molar equilibrium constants. The behavior of these various parameters under respiratory and metabolic acid-base disturbances for constant and variable buffer ion concentrations is considered. For constant noncarbonate buffer concentrations, DeltaSID = DeltaCB = DeltaVSSB, whereas these equalities no longer hold under changes in noncarbonate buffer concentration. The equivalence is restored if the reference state is changed to include the new buffer concentrations. 相似文献
190.
This paper discusses stochastic analysis of the ash handling system in a thermal power plant. The system consists of four subsystems Ai, Bj, C and Dk in series, with three possible states: good, reduced and failed. Failure and repair rates for each subsystem are taken to be constants. Using a probabilistic approach, the differential equations are generated and the expression for steady state availability is computed. Taking data from the thermal power plant, situated in North India, the behaviour of each working unit is analysed. Problems and remedies with appropriate maintenance schedules have been discussed. The results are discussed with the plant personnel and are helpful to the management in predicting the behaviour of each operating unit, so that timely decisions can be taken for maintaining the system in upstate for a long duration. 相似文献