Polarized Raman spectra of oriented fibers of calf thymus DNA in the A and B conformations have been obtained by use of a Raman microscope operating in the 180 degrees back-scattering geometry. The following polarized Raman intensities in the spectral interval 200-1800 cm-1 were measured with both 514.5 and 488.0 nm laser excitations: (1) Icc, in which the incident and scattered light are polarized parallel to the DNA helical axis (c axis); (2) Ibb, in which the incident and scattered light are polarized perpendicular to c; and (3) Ibc and Icb, in which the incident and scattered light are polarized in mutually perpendicular directions. High degrees of structural homogeneity and unidirectional orientation were confirmed for both the A and B form fibers, as judged by comparison of the observed Raman markers and intensity anisotropies with measurements reported previously for oligonucleotide single crystals of known three-dimensional structures. The fiber Raman anisotropies have been combined with solution Raman depolarization ratios to evaluate the local tensors corresponding to key conformation-sensitive Raman bands of the DNA bases and sugar-phosphate backbone. The present study yields novel vibrational assignments for both A DNA and BDNA conformers and also confirms many previously proposed Raman vibrational assignments. Among the significant new findings are the demonstration of complex patterns of A form and B form indicator bands in the spectral intervals 750-900 and 1050-1100 cm-1, the identification of highly anisotropic tensors corresponding to vibrations of base, deoxyribose, and phosphate moieties, and the determination of relatively isotropic Raman tensors for the symmetrical stretching mode of phosphodioxy groups in A and B DNA. The present fiber results provide a basis for exploitation of polarized Raman spectroscopy to determine DNA helix orientation as well as to probe specific nucleotide residue orientations in nucleoproteins, viruses, and other complex biological assemblies.

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Surfactant proteins (SP)-A and SP-D are collagen-like glycoproteins belonging to the "collectin" class of C-type lectins, which are primarily synthesized in type II cells. Recent studies reported the possibility of local production of SP-A and SP-D in the airways, but the amounts of surfactant proteins in patients with bronchial asthma have not been studied.The composition of surfactant proteins in mild, stable asthmatics in the first lavage as bronchial lavage (BL) and the second and third lavages consecutively as alveolar lavages (AL) were therefore, analysed separately. The co-relationships in the BL between the amounts of surfactant proteins and those of fucose, which is one of the markers of submucosal secretion were also analysed.Increased amounts of SP-A in BL and AL of in asthmatics were found as compared with those in controls. A high concentration of SP-D in the AL asthma patients was also found. The levels of SP-A correlated with those of fucose in patients with bronchial asthma (r=0.849, p<0.01).The observations in the present study suggested that surfactant protein A may be secreted from the airways with allergic inflammation in a different manner from the alveoli. The increased levels of surfactant proteins A and D may play a protective role in an allergic inflammation in the pathogenesis of bronchial asthma. Eur Respir J 2000; 16: 831±835.

A general method is presented for determining the shape and orientation of the Raman tensor of a molecule in a uniaxial crystal using a Raman microscope. First, equations are derived to connect the Raman tensor components (axx, a, , etc.) of a molecule to the Raman tensor components (aaa, a,,, etc.) of a crystal that is composed of molecules in a uniaxial arrangement, with an orientation specified by the two angles x and 9. Next, a method is presented to obtain a correct set of values of the intensity ratios Zac/Zaa and ZJZm from observed values of the intensity ratios measured with a Raman microscope. To augment the experimental data, the depolsrization ratio p (for a completely random molecular orientation) is plotted as a function of r l = axx/azz and rz = ay,,/azz, so that a possible set of r , and r z values can be found from an observed value of p. The method has been applied to an aspartame IIA crystal (P4,). A set of values of r,, r z , x and 9 has been determined for each of the following Raman fundamentals: 1741 cm-' (ester C -0 stretch), 1667 cm-' (amide I ) , 1275 cm-' (amide 111) and 1204 em-' (C-C,,,,,, stretch), excited at 488.0 nm.

Ca2+ accumulation and release from intracellular organelles is important for Ca2+-signalling events within cells. In a variety of cell types, the active Ca2+-pumping properties of endoplasmic reticulum (ER) have been directly studied using chemically permeabilized cells. The same preparations have been extensively used to study Ca2+ release from ER, in particular, release mediated by the intracellular messenger inositol 1,4,5-trisphosphate (InsP3). So far, these studies and others using microsomal membrane fractions have revealed few mechanistic details of Ca2+ release from ER, although a recent report indicated that InsP3-mediated Ca2+ release from liver microsomes may be dependent on GTP. In contrast to the latter report, we describe here the direct activation of a specific and sensitive guanine nucleotide regulatory mechanism mediating a substantial release of Ca2+ from the ER of cells of the neuronal cell line N1E-115. These data indicate the operation of a major new Ca2+ gating mechanism in ER which is specifically activated by GTP, deactivated by GDP, and which appears to involve a GTP hydrolytic cycle.

Polarized Raman scattering measurements have been made of a single crystal of L‐tyrosine by the use of a Raman microscope with the 488.0‐nm exciting beam from an argon ion laser. The L‐tyrosine crystal belongs to the space group P212121 (orthorhombic), and Raman scattering intensities corresponding to the aa, bb, cc, ab and ac components of the crystal Raman tensor have been determined for each prominent Raman band. A similar set of measurements has been made of L‐tyrosine‐d4, in which four hydrogen atoms on the benzene ring are replaced by deuterium atoms. The effects of NH3 → ND3 and OH → OD on the Raman spectrum have also been examined. In addition, depolarization ratios of some bands of L‐tyrosine in aqueous solutions of pH 13 and pH 1 were examined. For comparison with these experimental results, on the other hand, ab initio molecular orbital calculations have been made of the normal modes of vibration and their associated polarizability oscillations of the L‐tyrosine molecule. On the basis of these experimental data and by referring to the results of the calculations, discussions have been presented on the Raman tensors associated to some Raman bands, including those at 829 cm−1 (benzene ring breathing), 642 cm−1 (benzene ring deformation), and 432 cm−1 (Cα‐Cβ‐Cγ bending). © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: 61–71, 1998

Articles you may be interested inThe gas phase structure of trifluoromethylisocyanide CF3NC. An electron diffraction and microwave spectroscopy study J. Chem. Phys. 80, 4020 (1984); 10.1063/1.447282 Molecular structure of cyclobutane. Correction of the nematic phase NMR results for ring puckering motionThe electron diffraction intensity of cyclobutane was measured and analyzed conjointly with the rotational constant, Bo = 0.355 82( 11) cm -I, determined by an analysis of FTIR spectra ofthe V I4 (CH 2 scissoring, B!g) and VI6 (CH 2 rocking, A 2u ) bands. The r z structure was determined to be r z (C-C) = 1.552 ± 0.001 A, r z (C-H) = 1.093 ± 0.003 A, a z (LHCH) = 106.4 ± 1.30, and the ring dihedral angle, 8 z = 27.9 ± 1.6°; the rg distances of the C-C and C-H bonds are 1.554 ± 0.001 and 1.109 ± 0.003 A, respectively. The uncertainties represent estimated limits of error. The rocking angle {3z between the bisectors of the adjacent H-C-H and C-C-C angles was found to be 6.2 ± 1.2°, the axial C-H bonds in the 1,3 positions being tilted towards each other. The coefficient of coupling of the ring-puckering and CH 2rocking motions was estimated to be {3z18 z = 0.22 ± 0.05. The combination and difference sideband structures appearing in the V I 4 band due to the puckering mode V6 were analyzed. The puckering energy levels thus obtained were consistent with the existing data. A doubleminimum potential function for the puckering mode was determined by taking into account the coupling of the puckering motion with the CH 2 -rocking motion. The potential gave the zero-point vibrational average value of the ring dihedral angle, 27.5 ± 1.10, which agreed with t~at determined in the ED-IRjoint analysis mentioned above. The puckering potential for C 4 Dg was found to be consistent with that for C 4 Hg when the coupling between the puckering and the rocking motions was considered.

Since the 1970s, the burden of caregiving has been the subject of rather intense study, a trend that will continue with the rapid graying of populations worldwide. Since the Long-Term Care insurance system began in 2000, few cross-sectional studies have attempted to identify factors related to the feelings of burden among caregivers looking after the impaired elderly in Japan. In the present report, among 46 pairs of caregivers and impaired elderly, the elderly receiving regular nurses' visits in Kyoto Prefecture, Japan were assessed for problems with activities of daily living, the severity of dementia, the presence of behavioral disturbance, and cognitive impairment. The caregivers were asked to complete questionnaires in relation to their feelings of burden and caregiving situation. The results indicated that caregivers of impaired elderly with behavioral disturbances were more likely to feel a 'heavier burden.' Those temporarily relieved of caregiving three or more hours a day were less likely to experience 'heavier' caregiver burden than those who were not. Moreover, caregivers who found it 'inconvenient' to use care services tended to be more likely to feel a 'heavier' caregiver burden than those who did not. Recourse to respite services, which are ideally positioned to help, proved inconvenient because of their advance reservation system. More ready access to respite services in emergencies could do much to reduce caregiver burden.