Cloning of a cDNA encoding the smallest neurofilament protein from the rat

We have cloned a cDNA coding for the smallest rat neurofilament protein. The cDNA is 861 nucleotides long coding for 287 amino acids from the internal alpha-helical region and the carboxy-terminal tail domain of the neurofilament protein. Comparison of the porcine, mouse and rat neurofilament protein sequences shows that the protein is highly conserved (greater than 93% identity). Blot analysis indicates that the cDNA is derived from a single neurofilament gene that codes for two different poly(A)+ mRNA species.     

The inhibition of neutrophil granule enzyme secretion and chemotaxis by pertussis toxin

Pertussis toxin treatment of rabbit peritoneal neutrophils causes a concentration-dependent inhibition of granule enzyme secretion induced by formylmethionyl-leucyl-phenylalanine, C5a, and leukotriene B4. It also inhibits chemotaxis induced by formylmethionyl-leucyl-phenylalanine. The same toxin treatment, however, has no effect on granule enzyme secretion induced by the calcium ionophore A23187 or phorbol 12-myristate 13-acetate. Moreover, pertussis toxin treatment does not affect either the number or affinity of the formylpeptide receptors on the neutrophil nor does it have any effect on the unstimulated levels of cyclic AMP (cAMP) or the transient rise in cAMP induced by chemotactic factor stimulation in these cells. We hypothesize that pertussis toxin, as in other cells, interacts with a GTP binding regulatory protein identical with or analogous to either Ni or transducin which mediates the receptor-induced inhibition or activation of a target protein or proteins required in neutrophil activation. The nature of the target protein is unknown, but it is not the catalytic unit of adenylate cyclase. The target protein acts after binding of chemotactic factor to its receptor in the sequence that leads to the receptor-induced rise in intracellular Ca2+. It does not affect the responses elicited by the direct introduction of calcium into the cells or the activity of protein kinase C.     

IncP-1 R plasmids decrease the serum resistance and the virulence of Pseudomonas aeruginosa

Pseudomonas aeruginosa strain PAO1 was compared to PAO1 strains containing an IncP-1 R plasmid (RP1, R68, or R68.45) in an experimental mouse burn infection model. All R plasmids tested caused a 10- to 400-fold increase in mean lethal dose (LD50). The decrease in virulence produced by plasmids R68 and R68.45 was significantly greater than the decrease caused by the closely related plasmid RP1. All plasmids also led to an increased sensitivity of strain PAO1 to human serum bactericidal activity. Virulence and serum resistance of strain PAO1 were restored by curing of the entire plasmid R68.45 but not by deletions in the plasmid's transfer gene regions.     

Sensitization to stress: the enduring effects of prior stress on amphetamine-induced rotational behavior

In rats with a unilateral 6-OHDA lesion of the substantia nigra exposure to footshock or immobilization stress produced a long-lasting enhancement in the rotational behavior evoked by a subsequent injection of amphetamine. However, the effect was dependent on the environmental context in which stress was applied. It is suggested that stress may induce enduring changes in brain and behavior similar to those produced by psychomotor stimulant drugs.     

Solution-phase disproportionation equilibria for monosubstituted Pentakis- (arylisocyanide)cobalt(I) complexes by proton-NMR studies

Equilibrium constants, K_dis, for the solvent- dependent, solution-phase disproportionation equilibria of monosubstituted pentakis(arlisocyanide)cobalt(I) complexes: 2[Co(CNR)₄L]⁺?[Co(CNR)₃L₂]⁺ + [Co(CNR)₅]⁺, K_dis = $\text{[Co(CNR)}{}_3\text{L}{}_2\text{][Co(CNR)}{}_5\text{]}\text{[Co(CNR)}{}_4\text{L]}{}^2$ are measured by planimeter-integration of proton- NMR spectra at ambient temperature. The complexes, [Co(CNR)₄L]ClO₄, R = 2,6-Me₂C₆H₃, L = P(C₆H₅)₃, P(C₆H₄Cl-p)₃, P(OC₆H₅)₃, P(OC₆H₄Cl-p)₃; R = o-MeC₆H₄, L = P(C₆H₄Cl-p)₃, P(OC₆H₅)₃, P(OC₆H₄Cl-p)₃; R = 2,4,6-Me₃C₆H₂, L = P(C₆H₅)₃; R = 2,6-Et₂C₆H₃, L = P(C₆H₅)₃; are investigated in the deuterated solvents, CDCl₃, CD₃CN, (CD₃)₂CO, C₅D₅N, CD₃NO₂, and (CD₃)₂SO. Disproportionation seems to occur in all [Co(CNR)₄L]⁺, but NMR study is facilitated by utilizing equivalent alkyl protons (i.e., Me-groups) on the RNC ligands.Correlation of K_dis values with steric-hindrance of the RNC in sets of complexes with the same P-ligand is evident in all solvents: K_dis decreases with increased steric-hindrance in RNC. The K_dis values for complexes with the same RNC and analogous triarylphosphine, triarylphosphite ligands (i.e., PR₃, P(OR)₃, same R) are approximately equal. The K_dis values for complexes of P-ligands with Cl-substituent are significantly larger than K_dis values for complexes with the corresponding unsubstituted P-ligands (e.g., [Co(CNR)₄P(C₆H₄Clp)₃]ClO₄vs. [Co(CNR)₄P(C₆H₅)₃]ClO₄) in (CD₃)₂CO and C₅D₅N solution, but are smaller in CDCl₃ and CD₃CN, and approximately equal in CD₃NO₂ and (CD₃)₂SO. Properties of the solvents are also considered.     

Autoradiographic studies with fatty acids and some other lipids: A review

In this review, we have mainly included studies in which whole-body autoradiography was used. In lipid research, most studies have been done with fatty acids. These studies showed some common characteristics in the pattern of tissue distribution. A major uptake was seen in the brown fat, liver and adrenal cortex but also to some extent in other tissues with a high metabolic activity or high cell turn-over, e.g. the gastric and intestinal mucosa, diaphragm, kidney cortex and bone marrow. Low levels of radioactivity were generally found in the brain, testes, thymus, white fat, skeletal muscles, lungs and spleen. Most fatty acids showed some specific features, e.g the strong uptake of erucic, arachidonic and docosahexaenoic acid in myocardium and of eicosapentaenoic acid in the adrenal cortex. Studies with PGE1 and LTC3 showed that the liver and kidney and to a lesser degree the lungs were the major sites of metabolism. The distribution of free cholesterol and triolein emulsion labelled in the fatty acid moieties did show some similarities with respect to the general pattern found with most fatty acids. Specific for cholesterol was a very strong uptake in the adrenal cortex. There was also a significant uptake in the spleen whereas the uptake in the brown fat was not as marked as for most fatty acids. Specific for triolein was a marked uptake in the spleen and myocardium, in fed animals also in the white adipose tissue. These studies show that whole-body autoradiography can give much valuable information of the uptake and distribution of lipids that would be rather difficult to obtain with conventional methods. Combined with electron-microscopy, autoradiography can be used to study cellular and even subcellular distribution, and thus given further data on the metabolism of lipids in the body.     

Biofeedback control of migraine headaches: A comparison of two approaches

In order to assess the relative effectiveness of finger warming and temporal blood volume pulse reduction biofeedback in the treatment of migraine, 22 female migraine patients were assigned to one of three experimental conditions: temporal artery constriction feedback, finger temperature feedback, or waiting list. Biofeedback training consisted of 12 sessions over a 6-week period. All patients completed 5 weeks of daily self-monitoring of headache activity (frequency, duration, and intensity) and medication before and after treatment. Treatment credibility was assessed at the end of Sessions 1, 6, and 12. Results showed that temporal constriction and finger temperature biofeedback were equally effective in controlling migraine headaches and produced greater benefits than the waiting list condition. Power analyses indicated that very large sample sizes would have been required to detect any significant differences between the two treatment groups. No significant relationships were found between levels of therapeutic gains and levels of thermal or blood volume pulse self-regulation skills. Likewise, treatment outcome was not found to be related to treatment credibility. Further analyses revealed that changes in headache activity and medication were associated with changes in vasomotor variability. Because blood volume pulse variability was not significantly affected by biofeedback training, questions about its role in the therapeutic mechanism are raised.This research was supported in part by grants from the Quebec Ministry of Education and the Quebec Ministery of Social Affairs to the first author, and an award from the Medical Research Council of Canada to the second author. The authors are indebted to Drs. Frank Andrasik, Howard Barbaree, Edward Blanchard, Martin Ford, and Patrick McGrath, as well as to two anonymous reviewers, for their helpful comments on an earlier draft of this paper.     

Inhibierungserscheinungen bei der alkoholischen Gärung,I. Einfluß der Ethanolkonzentration auf die spezifische Ethanolbildungsgeschwindigkeit von Saccharomyces cerevisiae

Differential values of the specific ethanol production rate \documentclass{article}\pagestyle{empty}\begin{document}$$ v_{(t)} = \frac{1}{{x_{(t)} }} \cdot \frac{{dP}}{{dt}} $$ \end{document} can be calculated exactly from experimental batch fermentation process data by use of a nonlinear regression programme. The method used is based on the fact, that the function P = f(t) can be approximated by an exponential equation. The specific ethanol production rate is calculated then from the first differential derivation of this equation using the appropriated values of actual biomass concentration. For two strains of Saccharomyces cerevisiae a linear and nonlinear kinetic pattern, respectively, was found for product formation. This result can be explained by a simple mathematical relation according to ν=ν₀ ? a . P^b,in which the exponent becomes 1 in the case of linear kinetic pattern.     

The ultrastructure of the midgut and the formation of peritrophic membranes in a harvestman,Phalangium opilio (Chelicerata Phalangida)

Summary The ultrastructure of the midgut epithelium of Phalangium opilio was examined. In the anterior part of the midgut the epithelium consists of three different types of cells, called resorption, digestion, and excretion cells according to their presumed functions. Excretion cells may represent old digestion cells. The relation between resorption and digestion cells needs further investigation. The epithelium of the posterior part of the midgut consists of two types, transport and secretion cells, which seem to serve mainly for the resorption of water and the secretion of peritrophic membranes, respectively.Peritrophic membranes are secreted by the anterior midgut epithelium mainly in a period between 2 and 4 h after feeding. Chitin or chitin precursors could be localized in vesicles and in the brush border of midgut cells, and in the peritrophic membranes, using colloidal gold labelled with wheat germ agglutinin. Two different textures of chitin-containing microfibrils were found in the peritrophic membranes, either a random or a hexagonal texture. The latter results if the microfibrils polymerize between the basal parts of the microvilli. Irregularities of the hexagonal texture can be correlated with an irregular pattern of the microvilli. In the posterior midgut peritrophic membranes with a random texture, chitin-containing microfibrils are continuously secreted in the form of patches.