New bulky chiral Lewis acid catalyst: 3,3'-di(2-mesitylethynyl)binaphthol-titanium(IV) complex

A new chiral Lewis acid catalyst 9 was prepared in situ from a 1:2 molar mixture of (R)-3,3'-di(2-mesitylethynyl)binaphthol (6) and titanium(IV) isopropoxide at ambient temperature. The 3- and 3'-substituents on 6 were effective for preventing undesired aggregation between Ti(IV) complexes and increasing the enantioselectivity (up to 82% ee) in the Diels-Alder reaction of methacrolein with cyclopentadiene.     

Normal myocardial function in severe right ventricular volume overload hypertrophy

Severe left ventricular volume overloading causes myocardial and cellular contractile dysfunction. Whether this is also true for severe right ventricular volume overloading was unknown. We therefore created severe tricuspid regurgitation percutaneously in seven dogs and then observed them for 3.5-4.0 yr. All five surviving operated dogs had severe tricuspid regurgitation and right heart failure, including massive ascites, but they did not have left heart failure. Right ventricular cardiocytes were isolated from these and from normal dogs, and sarcomere mechanics were assessed via laser diffraction. Right ventricular cardiocytes from the tricuspid regurgitation dogs were 20% longer than control cells, but neither the extent (0.171 +/- 0.005 microm) nor the velocity (2.92 +/- 0.12 microm/s) of sarcomere shortening differed from controls (0.179 +/- 0.005 microm and 3.09 +/- 0.11 microm/s, respectively). Thus, despite massive tricuspid regurgitation causing overt right heart failure, intrinsic right ventricular contractile function was normal. This finding for the severely volume-overloaded right ventricle stands in distinct contrast to our finding for the left ventricle severely volume overloaded by mitral regurgitation, wherein intrinsic contractile function is depressed.     

Secretion of hen egg white lysozyme from Kluyveromyces lactis

Hen egg white (HEW) lysozyme was correctly processed and efficiently secreted from an alternative yeast, Kluyveromyces lactis. We constructed secretion vectors using PHO5, PGK, and LAC4 promoters, and found that the highest secretion was obtained under the direction of the PGK promoter in non-selective rich medium. K. lactis secreted HEW lysozyme with two-fold higher efficiency than S. cerevisiae, estimated by using a K. lactis-S. cerevisiae shuttle vector.     

Effects of color temperature of fluorescent lamps on body temperature regulation in a moderately cold environment

A study on the effects of different color temperatures of fluorescent lamps on skin and rectal temperatures in a moderately cold environment involving (i) changes in skin temperature of 7 male subjects exposed to an ambient temperature ranging from 28 degrees C to 18 degrees C (experiment I) and (ii) changes in skin and rectal temperatures and metabolic heat production of 11 male subjects exposed to ambient temperature of 15 degrees C for 90 min (Experiment II) was conducted. In Experiment I, the reduction of mean skin temperature from the control value was significantly greater under 3000 K than under 5000 K or 7500 K lighting. In Experiment II, the reductions in mean skin temperature and rectal temperature were respectively greater and smaller under 3000 K than those under 5000 K or 7500 K lighting. However, metabolic heat production was not affected by color temperature conditions. The relationships between morphological and physiological parameters revealed that no significant relation of rectal temperature to body surface area per unit body weight was found only under 3000 K. Furthermore, while the mean skin temperature was independent on the mean skinfold thickness under 3000 K, a significant negative correlation between the rectal and mean skin temperatures was observed. Therefore, body heat loss might be suppressed effectively by increasing the vasoconstrictor tone under a color temperature of 3000 K, and the body shell was dependent only on morphological factors under 5000 K and 7500 K lighting.     

Evidence for requirement of NADPH-cytochrome P450 oxidoreductase in the microsomal NADPH-sterol Delta7-reductase system

Rabbit antibodies raised against the hydrophilic part of microsomal NADPH-cytochrome P450 oxidoreductase (denoted fpT) demonstrated a marked ability to inhibit NADPH-sterol Delta7-reductase activity. In addition, trypsin and proteinase K treatment of microsomes removed almost all microsomal electron transfer constituents from the microsomes, but the Delta7-reductase activity could be reconstituted by adding detergent-solubilized NADPH-cytochrome P450 oxidoreductase (denoted OR). Furthermore, after solubilization from microsomes, the Delta7-reductase activity could be reconstituted with OR in a DEAE-cellulose column chromatography eluate fraction, which contained little OR activity. In the microsomal system, carbon monoxide, ketoconazole, and miconazole, specific inhibitors of cytochrome P450, had no effect on Delta7-reductase activity. These results provide the first evidence of an essential requirement of OR, which is distinct from cytochrome P450, in the NADPH-sterol Delta7-reductase system. EDTA, o-phenanthroline and KCN markedly lowered Delta7-reductase activity in a dose-dependent manner. Among metal ions tested, only ferric ion restored the reductase activity in the EDTA-treated microsomes. These results sugguest that NADPH-sterol Delta7-reductase is membrane-bound iron-dependent protein embedded in the microsomal lipid bilayer.     

Kin-related social organization in a winter population of the voleClethrionomys rufocanus

Kinship amongClethrionomys rufocanus was investigated during the winter of 1992/93 in a 3-ha enclosure using both molecular and catch-mark-release techniques. Forty-six adult voles (22 males and 24 females) having high heterozygosities, which were collected from several natural populations, were released into the enclosure on 29 September 1992. Most fall-born individuals of both sexes stayed in their natal site during the non-breeding period (December–March), although reproductively active females dispersed during the fall breeding season (October–November). These philopatric individuals aggregated and formed an maternal family in the winter. Several females which failed to reproduce were solitary during this season. Some individuals which were derived from several families also aggregated into a mixed lineage group. Survival rate of fall-born voles from earlier litters was higher than that from later ones. Maternal families broke up soon after the onset of spring reproduction. Most females established a territory near the wintering site and made a kincluster, in which close relatives neighbored each other. Maternal families in winter bring about female kin-clusters in spring, which may influence reproductive output in the breeding season.