Metachromasy of crystal violet in the presence of poly(alpha-L-glutamic acid) and the bound-dye spectra determined by the principal/component-analysis method

In order to study quantitatively the metachromatic behaviour of crystal violet (CV) in the presence of poly (alpha-L-glutamic acid), (poly (Glu)), four sets of the absorption spectra of the poly(Glu)-CV system were analyzed by the extended principal-component-analysis (PCA) method. Two classes of CV-Glu complexes, i.e., the bound-CV species, are present in poly(Glu) regardless of its helical and random-coiled conformations over a wide range of the mixing ratios of Glu residues to CV (P/D). The spectra of the bound CV in a low P/D range < 100 (complex I), extracted by the PCA method, are conformation-dependent showing three absorption bands at 506, ca. 550, and 610-620 nm. The spectra of the bound CV in a high P/D range > 100 (complex II) are closely related to, but not identical with, the free CV. The molar fractions of free CV and complexes I and II, evaluated in the P/D range of 0-150, indicate that CV binds more to the random-coiled poly(Glu) than to the helical one. Metachromasy of CV results from a complicated interplay of an unbound and two differently bound species.     

Photosynthetic activities of a thermophilic blue-green alga

Photosynthetic activities of a thermophilic blue-green alga,a species of Synechococcus, were studied with special referenceto its growth at high temperatures. A rapid algal growth occurredin the temperature range between 50 and 60?C, showing the maximumrate, six doublings per day, at about 57?C. Photosynthetic oxygenevolution and methyl viologen photoreduction in the cells werealso active at high temperatures and the optimum temperaturesfor these activities agreed with that of the algal growth. Thegrowth and photosynthetic activities were very low at room temperatureand irreversibly inactivated at temperatures above 60?C. The thylakoid membranes isolated from the alga were also photochemicallyactive at high temperatures. The membranes mediated ferricyanidephotoreduction coupled with a stoichiometric oxygen evolutionat a rate comparable to that of photosynthetic oxygen evolutionin the cells. The optimum temperature for the reaction was ashigh as 50?C. The membranes also showed a photosystem I-mediatedreaction at high temperatures. These observations indicate thatthe thylakoid membranes are intrinsically thermophilic in thisorganism. Thus the growth of the alga at high temperatures canbe well correlated to thermophilic properties of the photosyntheticapparatus. (Received February 20, 1978; )     

Description of the neotype ofRepomucenus sagitta (Callionymidae) with comments on the species

The neotype ofRepomucenus sagitta is described. Specimens conspecific with the neotype from India, the Gulf of Thailand, the South China Sea, the Yellow Sea and Australia are described. Sexual characters, geographic variation, habitat and geographic distribution were noted.Repomucenus macdonaldi is a junior synonym ofR. sagitta as defined by the neotype.     

Linkage studies in familial Alzheimer disease: Evidence for chromosome 19 linkage

A genetic component in the etiology of Alzheimer disease (AD) has been supported by indirect evidence for several years, with autosomal dominant inheritance with age-dependent penetrance being suggested to explain the familial aggregation of affecteds. St. George Hyslop et al. reported linkage of familial AD (FAD) in four early-onset families (mean age at onset [M] less than 50 years). Subsequent studies have been inconsistent in their results; Goate et al. also reported positive lod scores. However, both Pericak-Vance et al.'s study of a series of mainly late-onset FAD families (M greater than 60 years) and Schellenberg et al.'s study failed to confirm linkage to chromosome 21 (CH21). These various studies suggest the possibility of genetic heterogeneity, with some families linked to CH21 and others unlocalized. Recently, St. George Hyslop et al. extended their analysis to include additional families. The extended analyses supported their earlier finding of linkage to CH21, while showing strong evidence of heterogeneity between early-onset (M less than 65 years) and late-onset (M greater than 60 years) FAD families. Because our families did not show linkage to CH21, we undertook a genomic search for an additional locus for FAD. Because of both the confounding factor of late age at onset of FAD and the lack of clear evidence of Mendelian transmission in some of our families, we employed the affected-pedigree-member (APM) method of linkage analysis as an initial screen for possible linkage. Using this method, we identified two regions suggesting linkage: the proximal long arm of chromosome 19 (CH19) and the CH21 region of FAD linkage reported by St. George Hyslop et al. Application of standard likelihood (LOD score) analysis to these data support the possibility of an FAD gene locate on CH19, particularly in the late-onset FAD families. These data further suggest genetic heterogeneity and delineate this region of CH19 as an area needing additional investigation in FAD.     

Effect of aliphatic alcohols on the conformation of poly (l-ornithine hydrobromide) as studied by square-pulse and reversing-pulse electric birefringence

The electric birefringence and circular dichroism spectra of poly(l-ornithine hydrobromide) have been measured in ethanol/water, 2-propanol/water and tertiary butyl alcohol/water mixtures of various compositions. This charged polypeptide underwent a transition from the coil conformation to the helical conformation at high alcohol content in every case tested. Anomalous birefringence signals, indicative of a field-induced helix-to-coil transition. were observed at high electric fields only in the case of ethanol/water mixtures. The reversing-pulse electric birefringence of this polypeptide has been studied in ethanol/water mixtures and in neutral aqueous solution. Upon rapid reversal of the pulse field, no transient could be observed. This confirms that the electric-field orientation of poly(l-ornithine hydrobromide) results predominantly from the contribution of the counterion-induced dipole moment, regardless of its molecular conformations. It is very probable that the backbone permanent dipole moment of the helical conformation is largely suppressed by the counterion-induced dipole moment in the ionized form.     

Effect of pH, carbamylation and other hemoglobins on deoxyhemoglobin S aggregation inside intact erythrocytes as detected by proton relaxation rate measurements.

Measurement of the transverse water proton relaxation rate has been used to study the effect of pH, carbamylation, and other hemoglobins on the aggregation of deoxyhemoglobin S inside intact erythrocytes. Upon complete deoxygenation, cyanate-treated ($\text{S}\text{S}$) erythrocytes and erythrocytes heterozygous with respect to hemoglobin S ($\text{A}\text{S}$, $\text{C}\text{S}$, and $\text{S}\text{D}$) have high transverse water proton relaxation rates very similar to the values obtained with homozygous ($\text{S}\text{S}$) erythrocytes. These results suggest extensive intermolecular interactions between deoxyhemoglobin S molecules and a resultant increase in the correlation time for the small fraction of “irrotationally bound” water. When the transverse relaxation rate in deoxygenated ($\text{S}\text{S}$) erythrocytes was measured as a function of pH, the maximum rate was observed between pH 7.0 and 7.5. Upon increasing the pH beyond this range the observed relaxation rate decreases as does the number of sickled cells. Upon decreasing the pH, the observed transverse relaxation rate also decreases but the ratio of values from $\text{deoxy}\text{oxy}$ ($\text{S}\text{S}$) erythrocytes remains in the normal range of 4–6 and the number of sickled cells does not change. Therefore, the deoxyhemoglobin S aggregate inside sickled erythrocytes, as observed by water proton relaxation rates, is not altered by carbamylation or by the presence of nongelling hemoglobins. In addition, the enhancement of the relaxation rates as a function of pH is consistent with the number of sickled forms observed.