Studies of reaction parameters on synthesis of Citronellyl laurate ester via immobilized Candida rugosa lipase in organic media

Immobilized Candida rugosa lipase was used for the synthesis of citronellyl laurate from citronellol and lauric acid. Screening of different types of support (Amberlite MB-1 and Celite) for immobilization of lipase and solvent (n-hexane, n-heptane, and iso-octane) and optimization of reaction conditions, such as catalyst loading, effect of substrates molar ratio and temperature, have been studied. The maximum enzyme activity was obtained at 310 K. The immobilized C. rugosa lipase onto Amberlite MB-1 support was found to be the best support with a conversion of 89% of citronellyl laurate ester in iso-octane compared to Celite 545. Deactivation of C. rugosa lipase at 313, 318 and 323 K were observed. Ordered bi bi mechanism with dead end complex of lauric acid was found to fit the initial rate data and the kinetic parameters were obtained by non-linear regression analysis.

Peritoneal reflections of left perihepatic region: radiologic-anatomic study

To clarify the anatomy of the peritoneal reflections of the left perihepatic region, the authors examined 95 cadavers. Thirty-eight were studied radiographically, 37 with sagittal dissection, and 20 with transverse dissection. In over 80% of the cadavers, the left triangular ligament of the liver separated the left suprahepatic space into anterior and posterior sections. The lesser omentum extended to the diaphragm, where its anterior layer reflected and continued as the posterior layer of the left triangular ligament. Thus, the posterior left suprahepatic space and the lesser sac were clearly separated by the lesser omentum and the stomach and over-lapped each other in three dimensions. The posterior left suprahepatic space was located anterosuperior to the lesser sac and in turn was continuous with the gastrohepatic space inferiorly. Carefully researched diagrams of both the midline sagittal and left parasagittal perihepatic spaces were developed. This information has clinical value when the radiologist is called on to drain a left perihepatic abscess.

1H NMR study of renal trimethylamine responses to dehydration and acute volume loading in man

We have used volume-localized 1H NMR spectroscopy to detect and measure changes in medullary trimethylamines (TMAs) in the human kidney in vivo. Localized water-suppressed 1H spectra were collected from a volume of interest located within the renal medulla by using a stimulated echo-based localization scheme. The principal resonances in the medullary 1H spectrum were residual water (4.7 ppm), lipid (0.9-1.4 ppm), and TMAs (3.25 ppm). The TMA line width was 7-15 Hz before filtering, and the signal-to-noise ratio was 40:1. In four normal volunteers, 15 hr of dehydration led to a significant increase in urine osmolality and decrease in body weight and an increase in medullary TMAs. A subsequent water load [20 ml.(kg of body weight)-1] caused a transient water diuresis, a return to euvolemic body weight, and a significant reduction in medullary TMAs within 4 hr. These results suggest that TMAs may play an osmoregulatory role in the medulla of the normal human kidney.

Idiopathic Fanconi syndrome with progressive renal failure: a case report and discussion

Fanconi syndrome is a complex of renal tubular dysfunctions defined by glycosuria without diabetes, aminoaciduria, phosphaturia, and renal tubular acidosis. It is often associated with hypokalemia, hypophosphatemia, and rickets or osteomalacia. Although it is usually found in the setting of other well-established non-renal diseases, Fanconi syndrome may present without identifiable etiology or association. Very infrequently a patient with idiopathic Fanconi syndrome will progress to chronic renal failure. This case report details the course of such a patient over the 20 years since his diagnosis and discusses the syndrome's genetic background, clinical features, putative pathophysiology, and therapeutic options, including transplantation.

Prenatal diagnosis of mosaicism 46,XX/46,XX,-21,+t(21q21q)

Mosaicism for a structural chromosome abnormality in amniotic cell cultures indicative of true fetal mosaicism is a rare event. In addition to the laboratory findings the clinical interpretation for counseling in such cases is based on observation of the same abnormality in liveborns as well as previous experience with prenatal diagnosis of the same or similar abnormalities. We report here the prenatal diagnosis of 46,XX/46,XX,-21,+t( 21q21q ) which was confirmed in fetal skin cell and amnion cell cultures.

Current-voltage relationships for the plasma membrane and its principal electrogenic pump in Neurospora crassa: I. Steady-state conditions

The nonlinear membrane current-voltage relationship (I-V curve) for intact hyphae of Neurospora crassa has been determined by means of a 3-electrode voltage-clamp technique, plus "quasi-linear" cable theory. Under normal conditions of growth and respiration, the membrane I-V curve is best described as a parabolic segment convex in the direction of depolarizing current. At the average resting potential of - 174 mV, the membrane conductance is approximately 190 micronhos/cm2; conductance increase to approximately 240 micronhos/cm2 at -300 mV, and decreases to approximately 130 micronhos/cm2 at 0 mV. Irreversible membrane breakdown occurs at potentials beyond this range. Inhibition of the primary electrogenic pump in Neurospora by ATP withdrawal (with 1 mM KCN) depolarizes the membrane to the range of -40 to -70 mV and reduces the slope of the I-V curve by a fixed scaling factor of approximately 0.8. For wild-type Neurospora, compared under control conditions and during steady-state inhibition by cyanide, the I-V difference curve--presumed to define the current-voltage curve for the electrogenic pump--is a saturation function with maximal current of approximately 20 muA/cm2, a half saturation potential near -300 mV, and a projected reversal potential of ca. -400 mV. This value is close to the maximal free energy available to the pump from ATP hydrolysis, so that pump stoichiometry must be close to 1 H+ extruded:1 ATP split. The time-courses of change in membrane potential and resistance with cyanide are compatible with the steady-state I-V curves, under the assumption the cyanide has no major effects other than ATP withdrawal. Other inhibitors, uncouplers, and lowered temperature all have more complicated effects. The detailed temporal analysis of voltage-clamp data showed three time-constants in the clamping currents: one of 10 msec, for charging the membrane capacitance (0.9 muF/cm/2); a second of 50-75 msec; and a third of 20-30 sec, perhaps representing changes of intracellular composition.

Production of giant cells of Escherichia coli

Giant cells, with volumes up to 500-fold those of normal cells, have been produced by both genetic and pharmacological means in Escherichia coli K-12. In the genetic approach, an envB or mon mutation (conferring rounded or irregular morphology) was combined with a lon mutation (block of septation after irradiation). UV irradiation and subsequent incubation for 2 to 5 h in a rich medium supplemented with 1% sodium chloride led t; production of polymorphic giant cells. In the pharmacological approach, incubation of several different strains of E. coli K-12 with the drug 6-amidinopenicillanic acid (FL1060) in the same rich medium gave rise to a homogeneous population of smoothly rounded giant cells.

"Action potentials" in Neurospora crassa, a mycelial fungus

Occasional spontaneous "action potentials" are found in mature hyphae of the fungus Neurospora crassa. They can arise either from low-level sinusoidal oscillations of the membrane potential or from a linear slow depolarization which accelerates into a rapid upstroke at a voltage 5-20 mV depolarized from the normal resting potential (near-180 mV). The "action potentials" are long-lasting, 1-2 min and at the peak reach a membrane potential near-40 mV. A 2-to 8-fold increase of membrane conductance accompanies the main depolarization, but a slight decrease of membrane conductance occurs during the slow depolarization. Two plausible mechanisms for the phenomenon are (a) periodic increases of membrane permeability to inorganic ions, particularly H+ or Cl- and (b) periodic decreases in activity of the major electrogenic pump (H+) or the Neurospora membrane, coupled with a nonlinear (inverse signoid) current-boltage relationship. Identification of action potential-like disturbances in fungi means that such behavior has now been found in all major biologic taxa which have been probed with suitable electrodes. As yet there is no obvious function for the events in fungi.