Crystallization of human plasma apo-retinol-binding protein

Crystals of three forms of human plasma apo-retinol-binding protein have been obtained using the procedure described for the holoprotein. The apoprotein was prepared by a novel method, which uses hydrophobic interaction and immobilized dye chromatography. The three forms were separated by fast protein liquid chromatography. All of the crystals are isomorphous and diffract to 2.5 Å resolution. These crystals will be useful for studies of the mechanism of binding of retinol to its carrier using X-ray diffraction techniques.     

Heat resistance of bacterial spores correlated with protoplast dehydration, mineralization, and thermal adaptation

Twenty-eight types of lysozyme-sensitive spores among seven Bacillus species representative of thermophiles, mesophiles, and psychrophiles were obtained spanning a 3,000-fold range in moist-heat resistance. The resistance within species was altered by demineralization of the native spores to protonated spores and remineralization of the protonated spores to calcified spores and by thermal adaptation at maximum, optimum, and minimum sporulation temperatures. Protoplast wet densities, and thereby protoplast water contents, were obtained by buoyant density sedimentation in Nycodenz gradients (Nyegaard and Co., Oslo, Norway). Increases in mineralization and thermal adaptation caused reductions in protoplast water content between limits of ca. 57 and 28% (wet weight basis), and thereby correlated with increases in sporal heat resistance. Above and below these limits, however, increases in mineralization and thermal adaptation correlated with increases in sporal resistance independently of unchanged protoplast water contents. All three factors evidently contributed to and were necessary for heat resistance of the spores, but dehydration predominated.     

Central projections of labellar taste hairs in the blowfly,Phormia regina Meigen

Summary We have traced the central projections of the receptor neurons associated with each of the eleven largest taste hairs on the labellum of the blowfly, Phormia regina (Meigen), by staining them with cobaltous lysine. The eleven hairs fall into three groups which reflect their peripheral locations and their branching patterns in the subesophageal ganglion. Group 1, consisting of the anterior hairs (numbers 1 and 2) and Group 3, consisting of the posterior hairs (numbers 9–11) project bilaterally, while Group 2, consisting of the middle hairs (numbers 3–8) projects primarily ipsilaterally. The central projections of the hairs within a single group are similar. Each hair houses four chemoreceptors, which have differing chemical sensitivities and behavioral roles, and one mechanoreceptor. In some cases, there were indications that the different cells within a single hair have different central branching patterns. For some hairs, however, it was clear that a single central branching region and pattern was shared by more than one receptor cell. We failed to find either a continuous somatotopic representation of a hair's position on the periphery, or an anatomical segregation of receptors coding for different modalities. Behavioral experiments indicate that the fly is informed both of the identity of the hair stimulated and of the chemical nature of the stimulus. Our results suggest that this information is not represented on a gross anatomical level.     

Effect of thyrotropin on glycosaminoglycans synthesized by primocultured thyroid cells

The synthesis of glycosaminoglycans (GAGs) was investigated in porcine thyroid cells under the influence or not of thyrotropin. After labelling with [³H] glucosamine and [³⁵S] $\text{SO}{}_4{}^{\mathrm{2?}}$, enriched GAG-fractions prepared from culture media, cells, and eventually substrate adhering materials, were analyzed by cellulose acetate electrophoresis combined with specific degradations. They comprised heparan sulfate and hyaluronic acid together with an unknown sulfated component labile to endo-β-galactosidase. Whereas global labellings of newly made GAGs were not significantly modified by thyrotropin, we reproducibly observed with the hormone a substantial increase in the proportion of hyaluronic acid [³H] label and, when cells organized into follicles, of the proportion of cell-associated [³H] GAGs. This system thus offers an interesting model to study how the responsiveness to an hormone and the reorganization that follows might implicate specific glycoconjugates.     

Crystallization and preliminary X-ray data of human plasma retinol-binding protein

Crystals of human plasma retinol-binding protein have been obtained from 4.5 m-NaCl buffered at pH 6.8 with 20 mm-cacodylate. The crystals are trigonal with space group R3 and unit cell dimensions, referred to the hexagonal system. $\text{a = b = 104.2}\text{A}\text{?}\text{and}\text{c = 74.5}\text{A}\text{?}$. The crystals diffract to a resolution of 2.0 Å.     

Neuroendocrine modulation of haloperidol-induced catalepsy

Evidence has been accumulated implicating sex hormones as possible modulators of extrapyramidal motor function. In the present study we have investigated the effects of estrogens, progesterone, testosterone, prolactin and calcitonin on behavioral parameters related to nigro-striatal dopaminergic system, such as haloperidol-induced catalepsy in male rats. It was found that 7-days estradiol benzoate treatment (5 micrograms/rat/day) significantly increases haloperidol-induced catalepsy, suggesting a possible antidopaminergic activity of estrogens. On the other hand, prolactin facilitates nigro-striatal dopaminergic transmission. Interestingly, 7 day treatment with medroxy-acetate progesterone (MAP, 5 mg/Kg, i.p.) brings about a trend to a decrease in haloperidol-induced catalepsy, while no significantly effect was observed following acute MAP administration at the same dose. So, it is tempting to speculate that chronic progestinic treatment may result in an increase in dopaminergic tonus. Testosterone, acutely administered (5mg/kg.s.c.) induces changes similar to those observed following progesterone administration. Finally, also calcitonin is able to influence haloperidol-induced catalepsy by markedly increasing it.     

Inheritance of the allele Pr of the red cell acid phosphatase (EC. 3.1.3.2) in a Caucasian family

Summary The occurrence of the allele P^r showing an unexpected atypical isozyme band pattern in a Caucasian family is reported.