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We studied the time-course of stem response for six months following complete girdling in branches of Aquilaria sinensis to determine the potential role of interxylary phloem (IP) in this response. It was found that the vascular cambium, as well as its derivative secondary xylem and phloem, regenerated fully through redifferentiation of IP. We confirmed that vascular cambium regenerated within one month after girdling based on observation of new vessels, IP, and secondary phloem fibers. The time-course study showed that IPs made connections with each other, merged, and became larger through the proliferation of IPs parenchyma cells and the cleaving of secondary xylem in a narrow zone 400 to 1000 μm deep inside the girdled edge. This led to the formation of a complete circular sheath of vascular cambium, followed by the regeneration of vascular tissue. It is worth noting that the secondary xylem is regenerated always following the formation of a thick belt of wound xylem.

New observations of radial sieve tubes in the secondary xylem of two genera and four species of agarwood — Aquilaria sinensis, A. crasna, A. malaccensis and Gyrinops versteeghii (Thymelaeaceae) — are presented in this study. The earliest radial sieve tubes in Gyrinops are formed in the secondary xylem adjacent to the pith. The radial sieve tubes originate from the vascular cambium and develop in both uniseriate and multiseriate ray tissue. In addition to sieve plates in lateral and end walls, scattered or clustered minute sieve pores are localized in the lateral wall of radial sieve tubes. There is a direct connection between radial sieve tubes in ray tissue and axial sieve tubes in interxylary phloem strands (IP), such as (i) connection by bending of radial sieve tube strands, (ii) connection of two IP strands by an oblique bridge, and (iii) connection of two IP strands at a right angle. The average number of radial sieve tubes and interxylary phloem was found to be 1.7 per mm3 and 9.1 per mm2 in the secondary xylem. Considering the higher frequency of radial sieve tubes with the increasing thickness of the secondary xylem, the direct connections between radial and axial sieve tubes could play a significant role in assisting the translocation of metabolites in Aquilaria and Gyrinops.

The structure and development of interxylary phloem (IP) and external phloem in Aquilaria sinensis were investigated using light and scanning electron microscopy. Complete IP strands were isolated, measuring 14 ± 4 mm in length and 417 ± 124 μm in width. The outer margin of IP was composed of two to three layers of fusiform parenchyma cells. The development of IP can be divided into five stages: 1) Locally IP starts its differentiation within a small segment of a broad cambial zone, at the cost of xylem differentiation. 2) Inward growth of IP advances, and fibres and sieve tubes differentiate. 3) IP is constricted by the encroachment of immature xylem cells between cambium and immature IP. 4) IP is isolated from the cambium and surrounded by immature, non-lignified xylem tissue. 5) IP is surrounded by lignified xylem tissue, and the fibres within IP become lignified.In all the phloem islands in a ten-year-old stem, sieve elements showed positive staining of callose with aniline blue. However, no staining of callose was observed in the external secondary phloem of agarwood trees collected from two different sites. No sieve tubes or sieve pores were detected by SEM observation of numerous serial cross and radial sections of the external phloem. We therefore conclude that sieve tubes are absent from the external phloem or extremely rare and that the transport of photosynthetic products in the stem of A. sinensis takes place in the interxylary phloem.

Emission, excitation and absorption spectra of a new and short polyene, 2-(4-phenyl-1,3-butadien-1-yl)thiophene (PBT), have been measured under different conditions by varying temperature and solvent and in the vapor phase, along with those of 2-(2-phenylethenyl)-thiophene (PET). The presence of a forbidden excited singlet state, located at energies slightly below the strongly absorbing state, is indicated for PBT, although the forbidden state was not identified for PET. The emission of PBT consists of fluorescence from the allowed S2 and forbidden S1 states in low polarizable solvents, while it consists of florescence mainly from forbidden S1 in the vapor phase and that from allowed S1 state in high polarizable solvents. Quantitative analysis of the temperature dependence of the S1 and S2 fluorescence spectra provides the S1 and S2 state energies and physical parameters that characterize the excited states of PBT.

Pierinae, the major subfamily of Pieridae, is characterized by possessing scent scales as androconia on male wings, which are most likely to disperse volatile substances. However, the chemistry of androconial substances is known for very few species. The yellow tip Anthocharis scolymus Butler (Pierinae: Anthocharidini) is a univoltine pierine butterfly distributed in East Asia. Male adults of this species emit a subtle floral scent, while females are scentless. We revealed that the male-specific scent consists of (S)-(+)-linalool and (E)-β-farnesene, which had never been discovered in Pieridae. Moreover, these volatile terpenoids were more abundant in the wings than in the body, and were distributed from the basal to the distal regions of each wing. Unlike other pierine species, A. scolymus males lacked alar scent scales but had round saccular structures connected to the socket of the ordinary scale in the wing membrane. The morphology of this structure was very similar to those of the intermembranous scent-producing organs of male wings in the subfamily Coliadinae. Although scent scales are found in the genus Anthocharis, the presence of male-specific scents has not been reported so far. The present study illustrates unique characters of A. scolymus in both androconial chemistry and morphology in Pierinae.

Mucilage is extruded from the bark of Pseudolarix amabilis and Abies nephrolepis upon injury. The aim of this study was to characterize the structure and chemical contents of mucilage extruded from mucilage cells (MCs) in the bark of these species. A large number of MCs containing translucent or dark materials in their lumina were observed in the secondary phloem of P. amabilis and A. nephrolepis. The translucent or dark materials in MCs stained positive with ruthenium red and PAS, indicating the presence of polysaccharides. The average length and diameter of MC in P. amabilis were 1500 μm and 254 μm, respectively, and the corresponding values for A. nephrolepis were 419 μm and 166 μm. Chemical analysis of low molecular weight fractions prepared from mucilage by HPAEC-PAD showed sucrose, glucose and fructose peaks, and in addition galacturonic acid and fucose peaks. Furthermore, 1H NMR spectra for the high molecular weight fraction showed the signals characteristic of pectin. This demonstrates that the mucilage consists mainly of low molecular weight carbohydrates and high molecular weight polysaccharide pectin.

Fluorescence, fluorescence excitation and absorption spectra of 1,3,5-heptatrienylbenzene (MPP3) have been measured in the static vapour phase and in solution. It is shown that the MPP3 vapour exhibits prompt S2 and S1 fluorescence. The presence of two different mechanisms for the occurrence of the S2 fluorescence is demonstrated for MPP3. That is, the S2 fluorescence in the vapour phase is prompt fluorescence, the rate of which is fast enough to compete with internal conversion from S2 to S1, while in solution the S2 fluorescence occurs as the result of the thermal activation of the S1 state. The relaxation processes were discussed and the fluorescence property was compared with that of diphenylhexatriene.

Morphological studies of androconia were performed for 13 Celastrina species using a digital microscope with Z-stacking mode. Whereas C. ladon lacked androconia, the remaining 12 species were found to possess fan-shaped androconia on the dorsal wing surfaces. The androconia of these species shared the following common features: smaller size than standard color-producing scales, absence of dentate termini and presence of crossrib perforations. In addition, some species were characterized by unique microstructures in their androconia. The androconia of C. argiolus iynteana possessed a rounded lamellar contour, while those of C. lavendularis himilcon and C. echo cinerea were tapered on the basal end. The average number of longitudinal ridges of C. argiolus ladonides and C. filipjevi (17.1) were greater than the average number of 12 species (14.3). These results suggest that the morphological traits of androconia in microdomain, such as the shape of the lamellar form and the average number of longitudinal ridges, are useful to identify species in the genus Celastrina.

Pressure and temperature dependence of fluorescence and phosphorescence spectra have been investigated for quinoline in the static vapor phase. It is shown that the intensity of the T1(π, π*) → S0 phosphorescence relative to that of the S1(n, π*) → S0 fluorescence decreases with decreasing pressure and with increasing temperature. The relaxation processes of quinoline vapor are discussed based on the pressure and temperature dependence of the emission. The data include the vibrational analysis of the bands appearing in the T1(π, π*) → S0 phosphorescence spectrum.

Emission spectra of 3- and 4-hydroxybenzaldehyde vapors have been measured along with the excitation and absorption spectra. It is inferred from the temperature dependence of the phosphorescence spectrum that the phosphorescence of 4-hydroxybenzaldehyde vapor originates from the T 2 (n, π * ) state. In the case of 3-hydroxybenzaldehyde vapor, the emission is shown to consist of that of 3-hydroxybenzaldehyde and benzaldehyde vapors, with the latter molecule being generated as the result of photochemical decomposition of 3-hydroxybenzaldehyde. The interpretation of the emission spectrum of 3-hydroxybenzaldehyde is different from that reported previously. The rotational isomer responsible for appearance of the phosphorescence of 3-hydroxybenzaldehyde vapor is suggested based on DFT calculation and emission spectral data.

T 2 (n, π ∗ ) phosphorescence has been observed for 4-hyroxybenzaldehyde along with T 1 (π, π ∗ ) phosphorescence in a partially translucent 1,4-dichlorobenzene host upon increasing temperature. Quantitative analysis of the steady-state emission spectra and emission decay profiles measured as a function of temperature provides estimates for the excited-state energies and rate constants that characterize the excited-state dynamical behavior of 4-hydroxybenzaldehyde. It is shown that the successive occurrence of the T 1 (π, π ∗ ) and T 2 (n, π ∗ ) phosphorescence is caused by the thermal repopulation from the T 1 state.

Male adult butterflies of many species have characteristic odors originating from the disseminating organs known as androconia. Despite the fact that androconia exist in several species, there have been few investigations on adult scents from the lycaenid species. Celastrina argiolus ladonides (Lycaenidae) is a common species in Eurasia. We have reported that male adults of this species emit a faint odor, and the major components causing this odor have been newly found in the Insecta. By using field-caught individuals, we determined the chemical nature and location of this odor in the butterfly. Gas chromatography-mass spectrometry (GC-MS) analyses revealed that two lactone compounds, lavender lactone and δ-decalactone, are present in the extracts of males but absent in those of the females. On an average, approximately 50 ng of each compound was found per male. Chiral GC analyses performed using enantiomerically pure standards revealed that the natural lavender lactone was a mixture of two enantiomers with an R/S ratio of 32:68, whereas the natural δ-decalactone contained only the R-enantiomer. When the analyses were conducted using different parts-forewings, hindwings, and body-of three males, the lactones were more abundantly found on the forewings and hindwings than on the body. Microscopic observation of the wings demonstrated that battledore scales known as androconia are scattered on the upper surface of both the wings of C. argiolus ladonides males. These results indicate that the specialized scales on the wings of males serve as scent-disseminating organs.

S 1 and S 2 fluorescence and excitation spectra of all- trans -2,4,6,8,10-dodecapentaene vapor have been measured at different N 2 gas pressures from 0 to 800 Torr along with the absorption spectrum. Both S 1 and S 2 fluorescence quantum yields are shown to decrease with increasing excitation energy under the collision free condition, although the decrease of the latter yield is not significant. The difference between the S 1 and S 2 fluorescence lifetimes was demonstrated through the effect of added O 2 gas on the relative fluorescence intensities. Pressure and excitation-energy dependence of the S 1 and S 2 fluorescence yields are interpreted in terms of the relaxation model involving the fast S 2 → S 1 internal conversion followed by vibrational relaxation in the S 1 manifold. Estimates for the rates that characterize the excited-state dynamical behavior of decapentaene vapor have been extracted.

Emission and excitation spectra of 2,6-dimethyl-4H-pyran-4-thione (DPT) vapor have been measured at different buffer gas pressures from 0 to 300 Torr and at different temperatures. Emission property of DPT vapor is found to vary significantly depending on pressure, excitation energy and temperature. The quantum yields of S1 fluorescence (ΦF1) and T1 phosphorescence (ΦP) increase with increasing buffer gas pressure and with decreasing temperature, while that of the S2 fluorescence (ΦF2) is almost unchanged. The values for ΦP and ΦF1 decrease almost exponentially with increasing excitation energy at low pressure, although the decrease of ΦF2 is not so significant compared to ΦF1 and ΦP. These observations have been interpreted in terms of the relaxation model involving the fast S2 → S1 internal conversion followed by the fast S1 → T1 intersystem crossing and the vibrational relaxation in the T1 manifold along with the temperature dependent nonradiative process from T1.

Fluorescence, fluorescence excitation, biacetyl-sensitized phosphorescence excitation and absorption spectra of three fluoropyridines (2-fluoropyridine, 6-fluoropyridine and 2,6-difluoropyridine) have been measured in the vapor phase. The quantum yields of the S1 → T1 intersystem crossing of these fluoropyridines have been determined by means of a sensitized biacetyl phosphorescence method based on intermolecular T–T energy transfer. It is shown that the main nonradiative process in these fluoropyridines is the internal conversion S1 → S0, which may include possible photochemical decomposition processes. It is shown that the internal conversion rates increase almost exponentially with increasing excitation energy, while the increase of the S1 → T1 intersystem crossing rates is not significant.

Emission and excitation spectra of p -benzoquinone have been measured in a partially translucent p -dichlorobenzene host matrix at different temperatures from 77 up to 323 K. Successive occurrence of the T 1 (n,π ⁎ ) and T 2 (n,π ⁎ ) phosphorescence and S 1 (n,π ⁎ ) fluorescence has been observed for p -benzoquinone upon increasing temperature. The S 1 –T 2 and T 2 –T 1 energy separations determined from the temperature dependence of the emission intensities agreed well with those obtained from the locations of the T 1 and T 2 phosphorescence and S 1 fluorescence origins. Occurrence of the emission from S 1 and T 2 is brought by the thermal population from the T 1 state. The symmetries of the T 1 and T 2 states were determined to be B 1g and A u , respectively, based on the spectral data.

Fluorescence from upper excited states is surveyed as a milestone for future works. The mechanisms of the occurrence of such anomalous fluorescence are classified. The chemical species treated in the present review are aromatic molecules and linear polyenes in the papers reported up to 2013. Information on the fluorescence properties reported so far in numerous papers allows generalizations of the mechanism of the appearance of fluorescence from upper excited states. There are three intramolecular mechanisms for the occurrence of fluorescence from upper excited states for aromatic molecules and liner polyenes. That is, the fluorescence from the upper state occurs; (i) through thermal population from the lower excited state, S1; (ii) through reverse internal conversion from the lower singlet state under collision-free conditions (in this case the upper and lower singlet states are mixing); (iii) directly from the upper singlet state without involvement of the fluorescence component via reverse internal conversion from the lower singlet state, i. e., prompt fluorescence.

Energetics of the rotational isomers (rotamers) of 2- and 3-thiophenecarboxaldehydes has been investigated in Ar matrices by means of matrix-isolation infrared spectroscopy in the 700–1800 cm−1 region, combined with UV irradiation as well as DFT and Coupled Cluster calculations. Utilizing photo-induced rotational isomerism, the two rotamers (anti and syn) have been identified and the infrared bands of each rotamer have been assigned. The energy differences between the two rotamers in the ground state have been evaluated based on the infrared data, which are in excellent agreement with those obtained by the Coupled Cluster calculations.

Emission, excitation and absorption spectra of α-carotene have been measured in solvents with different polarizabilities. It is shown that in highly-polarized solvents α-carotene emits weak fluorescence from the S1(π,π∗) state with the fluorescence origin observed at 14 800 ± 200 cm−1. The relative S1/S2 fluorescence intensity ratio tends to increase with increasing solvent polarizability or decreasing the S1–S2 energy separation. The obtained spectroscopic data include the Raman spectrum of α-carotene along with the vibrational analyses of the Raman spectrum based on the DFT calculation at the B3LYP/6-31G(d,p) level.

Emission spectra of xanthone vapor have been measured at different temperatures along with the excitation and absorption spectra. Fluorescence from the S 1 ( n , π ∗ ), 1 A 2 and phosphorescence from the T 1 ( n , π ∗ ), 3 A 2 states were separated to extract only the fluorescence spectrum. The vibrational structure of the fluorescence was interpreted in terms of the C O stretching mode and the modes combined with the C O stretching, showing a maximum near 24 000 cm −1 . The locations of the S 1 and T 1 origins are observed at 26 940 and 25 700 cm −1 , respectively. Analysis of the data includes the determination of the vibrational frequencies in the fluorescence and phosphorescence.

Vertical and horizontal distributions of Oeneis norna have been investigated at the Hida mountain chain (Northern Japan Alps) in Japan. It is shown that the lower limit of the vertical distribution tends to decrease from the south to north. Linearity is seen between the lower and upper limits of the vertical distribution. The range of vertical distribution tends to narrow with lowering the upper altitudinal limit of the habitat. It is inferred from the horizontal distribution pattern of Oeneis norna in this area that the tephra (Tt-D) derived from the volcano of Mt. Tateyama and accumulated about 105 years ago, had an influence on the present distribution of this species in the Hida mountain chain.

Emission and absorption spectra have been measured for 2,3,4-, 2,3,5- and 2,4,5-trifluorobenzaldehyde vapors at different temperatures along with the Raman spectra of the pure samples. The observed emission is shown to consist of the T 1 (n, π∗) phosphorescence accompanied by the weak S 1 (n. π∗) delayed fluorescence for all the molecules. The vibrational analyses of the fluorescence and phosphorescence spectra based on the results of the DFT calculation at the B3LYP/6-311+G(p,d) level indicate that the observed emission and absorption originates from only the stable conformer (anti). The measured Raman spectra also agreed well with those calculated for the stable (anti) conformer.

Emission and excitation spectra of 2- and 3-fluoropyridine (2- and 3-FP, respectively) vapors have been measured under the different conditions. It is shown that 3-FP vapor emits weak fluorescence from the S 1 (n, π ∗ ) states. The fluorescence quantum yields are evaluated to be approximately 10 −3 and 10 −4 for 2- and 3-FP vapors, respectively, following the excitation into the S 1 origin. The fluorescence yields decrease significantly with increasing excitation energy. The decrease of the yield is more significant for 2-FP than for 3-FP vapor. The data include vibrational analyses of the hot bands in the excitation spectra using the DFT calculation at the B3LYP/6-311++G ∗∗ level.

Emission and absorption spectra have been measured for 2,3-, 2,4- and 2,5-difluorobenzaldehyde vapors at different temperatures. The observed emission consists of the T1(n, π∗) phosphorescence accompanied by the weak S1(n, π∗) delayed fluorescence for all the molecules. The vibrational analyses of the emission spectra based on the results of the DFT calculations indicate that the observed emission originates from only the stable (anti) conformer. It is inferred from the temperature dependence of the phosphorescence intensity that the T1(n, π∗) → T2(π, π∗) internal conversion and/or the reverse T1(n, π∗) → S1(n, π∗) intersystem crossing contribute to the decrease in the phosphorescence intensity upon increasing temperature. The obtained spectroscopic data include the Raman spectrum of 2,3-difluorobenzaldehyde.

Fluorescence and excitation spectra of all-trans-2,4,6,8-decatetraene vapour have been measured at different buffer gas pressures from 0 to 1.07 x 105 Pa (800 Torr). The quantum yield of the S1 fluorescence (phi F(S1)) increases with increasing the buffer gas pressure, while that of the S2 fluorescence (phi F(S2)) decreases slightly. phi F(S1) decreases significantly with increasing the excitation energy under the collision free condition, while phi F(S2) decreases only slightly. The pressure dependence of the fluorescence yields is interpreted in terms of the relaxation model involving the reversible internal conversion between S1 and S2 and the vibrational relaxation in the S1 manifold. The reverse S1 S2 internal conversion rate is shown to be very slow compared with the forward S2 S1 internal conversion rate.

Emission and excitation spectra of 3- and 4-pyridinecarboxaldehyde vapors have been measured at different pressures down to 10(-2)Torr. The phosphorescence quantum yield measured at low pressure as a function of excitation energy is nearly constant in the range of excitation energy corresponding to the S1(n, pi*) state, but it decreases abruptly at the S2(pi, pi*) threshold. The onset of the abrupt decrease of the yield corresponds to the location of the S2 absorption origin of each molecule, indicating that the nonradiative pathway depends on the type of the excited singlet state to which the molecule is initially excited. The relaxation processes are discussed based on the pressure and excitation-energy dependence of the phosphorescence quantum yield.

Fluorescence and excitation spectra of coronene vapor have been measured under different conditions. Weak emission which can be regarded as the fluorescence from the third excited singlet state, S3(1E1u), was observed in addition to the S1(1B2u) and S2(1B1u) fluorescence. The observed S2 and S3 fluorescence are substantially different from those reported previously for coronene vapor. Addition of oxygen resulted in significant decrease of the S1 fluorescence intensity, but did not affect the S2 fluorescence intensity, indicating the faster decay rate of the S2 state than that of S1. Excitation energy dependence of the S1, S2 and S3 fluorescence quantum yields (ΦF(S1), ΦF(S2) and ΦF(S3), respectively) revealed that ΦF(S1) decreases with increasing excitation energy, while ΦF(S2) and ΦF(S3) increase significantly. The quantum yield ratios, ΦF(S2)/ΦF(S1) and ΦF(S3)/ΦF(S2), obtained as a function of excitation energy are correlated with the ratios of the relative internal conversion rates.

Fluorescence and absorption spectra and fluorescence lifetimes have been measured for α,ω-dithenylbutadiene (DTB) and α,ω-dithenylethylene (DTE) in different solvents and at different temperatures as well as in the vapor phase. It is shown that the emission of DTB consists of the S2 (11Bu) and S1 (21Ag) fluorescence, while the emission of DTE consists of solely the S1 (11Bu) fluorescence. The 21Ag and 11Bu state levels of DTB are found to invert in solvents with the polarizability of near 0.32. All the available data for DTB on temperature and solvent dependence of the absorption and fluorescence spectra and the fluorescence lifetime support the presence of the lowest excited singlet state, 21Ag, located below the strongly allowed 11Bu state. Quantitative analyses of the spectral data provide the physical parameters that characterize the excited state dynamical behavior of DTB.

To further our understanding of wood decay in living light red meranti (Shorea smithiana) trees, microscopic characteristics of the cell and cell wall degradations of S. smithiana wood in the presence of the decay fungi, the identity of the causal fungi, and the decay potential and pattern by an isolated fungus were investigated. Cell wall degradations, including cell wall thinning, bore holes formation, rounded pit erosion, and eroded channel opening were clearly observed under light and scanning electron microscopy. In transverse view, many large voids resulting from a coalition of degraded wood tissue appeared in the decayed canker zone. All these observations suggest the well-known simultaneous decay pattern caused by white-rot fungi. By phylogenetic analysis based on the sequences of internal transcribed spacer region of ribosomal DNA, a basidiomycete fungus isolated from the decayed wood was identified as Schizophyllum commune. The degradation caused by this fungus on sound S. smithiana wood in an in situ laboratory decay test was classified as the early stage of simultaneous decay, and showed a similar pattern to that observed in the wood samples naturally decayed.

The fluorescence spectra obtained by the two-photon excitation into the 2 1 Ag state of diphenylbutadiene (DPB) have been measured in room temperature solutions, along with the one- and two-photon absorption spectra. It is shown that DPB molecule excited into the two-photon allowed 2 1 Ag state through the two-photon process exhibits the fluorescence from the two-photon forbidden 1 1 Bu state irrespective of the solvent polarizability. Relaxation processes followed by the two-photon excitation into the 2 1 Ag state, and the shape of the two-photon absorption spectra measured when the 2 1 Ag origin is located below the 1 1 Bu origin are discussed.

Rotational isomers (rotamers) of the three structural isomers of benzenedicarboxaldehydes (1,2-, 1,3-, and 1,4-derivatives) have been investigated in detail using matrix-isolation infrared spectroscopy in the 600-4000 cm-1 region, combined with UV photoexcitation and density-functional theory (DFT) calculations. Two rotamers were identified for 1,2- and 1,4-benzenedicarboxaldehyde (1,2- and 1,4-BDA, respectively), while three rotamers were identified for 1,3-benzenedicarboxaldehyde (1,3-BDA) in infrared spectra upon UV-irradiation. Most of the observed infrared bands of each rotamer have been assigned. The energetic relationships among the rotamers were revealed based on the infrared data and the DFT calculations. It is shown that the intramolecular C-H...H-C interaction in the H-syn rotamer or the C-H...O=C hydrogen bonding in the anti rotamer of 1,2-BDA results in the blue-shift of the aldehyde C-H stretching band and the shortening of the aldehyde C-H bond length. Both photoinduced rotational isomerization and rearrangement were observed upon UV irradiation for 1,2-BDA. The structure of the major enol isomer formed as the result of the photochemical rearrangement of 1,2-BDA is determined.

In the ciliated protozoan Blepharisma, step-up photophobic response is believed to be mediated by a novel type of photosensory pigment known as "blepharismins" (BL) that are contained in the pigment granules located just beneath the plasma membrane. We examined the ultrastructure of the pigment granules by freeze-fracture and thin-section electron microscopy and proposed a schematic diagram showing the granules' three-dimensional inner membranous structure. Some of the BL are suggested to be associated with 200 kDa membrane protein. High-pressure liquid chromatography analysis of pigment species associated with 200 kDa protein obtained from blue forms of Blepharisma (oxyblepharisma) revealed that the 200 kDa protein was associated with five types of oxyblepharismin. The fluorescence intensity was increased when the pigments were dissociated from the 200 kDa protein. The result supports the hypothesis that the pigment-200 kDa complex is able to transduce light energy into signals mediating the photobehavior of Blepharisma.

Fluorescence and fluorescence excitation spectra of diphenyloctatetraene vapor have been measured at different temperatures from 98 to 136 °C and at different buffer gas pressures from 0 to 300 Torr. The fluorescence quantum yields were determined as functions of the excitation energy and buffer gas pressure. It is shown that diphenyloctatetraene vapor exhibits weak fluorescence from the S2 (11Bu) state in addition to the fluorescence from the S1 (21Ag) state. The quantum yield of the S1 fluorescence is shown to decrease with decreasing pressure and with increasing excitation energy. The electronic relaxation processes of diphenyloctatetraene vapor are discussed based on the pressure and excitation-energy dependence of the fluorescence quantum yield.

Three structural isomers of pyridinecarboxaldehydes (2-, 3- and 4-pyridinecarboxaldehyde) have been investigated in detail with matrix-isolation infrared spectroscopy in the 3000.600 cm.1 region, combined with the UV photoexcitation and the density-functional theory (DFT) calculations. Two rotamers (anti and syn) were identified for 2- and 3-pyridinecarboxaldehyde (2- and 3-PCA, respectively) upon the photoexcitation and most of the observed bands of each rotamer have been assigned. Both of the infrared data and the results of the DFT calculations strongly support that the syn rotamer exists as a less stable isomer for 2- and 3-PCA. It is shown that the formation of the intramolecular C.H...N hydrogen bond for the anti rotamer of 2-PCA results in the shortening of the aldehyde C.H bond length, while for the syn rotamer the C=O bond length is shortened due to the repulsion between the N and aldehyde O atoms. With 2-PCA, the photoinduced rotational isomerism and photolysis were observed simultaneously upon the UV irradiation. Keywords: 2-, 3- and 4-Pyridinecarboxaldehyde, Rotamer, Matrix-isolation infrared spectroscopy, UV photoexcitation, Energetics, Density-functional theory calculation

Emission and excitation spectra of 2-, 3- and 4-pyridinecarboxaldehyde (2-, 3- and 4-PCA, respectively) vapors have been measured at different temperatures and compared to one another. The emission spectra of these vapors are shown to consist of the T(1)(n, pi) --S(0) phosphorescence accompanied by the weak thermally activated S(1)(n, pi) --S(0) delayed fluorescence. Two peaks originating from the two rotamers (syn and anti) have been identified in the fluorescence, phosphorescence and excitation spectra of 3-PCA vapor. Analyses of the temperature dependence and vibrational structure of the spectra of 3-PCA vapor provide the syn-anti energy difference of 190 +/- 30 cm(-1) in the T(1) (n, pi) state, 200 +/- 30 cm(-1) in the S(1)(n, pi) state, and 290 +/- 35 cm(-1) in the ground state. The ground-state energy difference is in agreement with the result of density functional theory (DFT) calculation for 3-PCA vapor. DFT calculation demonstrated also that the syn rotamer exists as a less stable isomer in the ground state for 2- and 3-PCA vapors.

A simple detection method to observe the uniplanar orientation behavior of native cellulose microfibrils to the cell wall surface by using Fourier transform infrared (FTIR) spectroscopy in the transmission mode is reported. Four bands at 1372, 1355, 1337, and 1317 cm−1 (the latter two have been mentioned previously by Liang and Marchessault (1960, J. Polym. Sci. 43: 85–100)) were found to be sensitive to such orientation: the two middle bands at 1355 and 1337 cm−1 increase remarkably when the 0.60–61 nm lattice planes lie parallel to the cell wall surfaces. The reverse was true when the 0.53–54 nm lattice planes oriented preferentially. Polarization of the two bands at 1372 and 1355 cm−1 was parallel, while that of the other two bands at lower wavenumbers, i.e., at 1337 and 1317 cm−1, was perpendicular to the molecular axis of cellulose. These bands were assigned to OH-related motion, probably to in-plane OH bending, as reported by Marechal and Chanzy (2000, J. Mol. Spectrosc. 523: 183–196).

The mechanism of the H-atom transfer from phenols or thiophenols to triplet π,π∗ 5,12-naphthacenequinone (5,12-NQ) has been examined by means of laser flash photolysis at 295 K. Based on the Hammett plots and the Rehm–Weller equation for the quenching rate constants, the phenolic H-atom transfer from phenols or thiophenols to triplet π,π∗ 5,12-NQ is shown to proceed via the electron transfer followed by proton transfer. The previously proposed mechanism for H-atom transfer of π,π∗ triplets, that proton transfer is followed by electron transfer, was not verified in the present systems.

Three structural isomers of fluorobenzaldehyde ( p -, m - and o -forms) have been investigated in detail with matrix-isolation infrared spectroscopy, in the 700–3000 cm −1 region, combined with the UV photoexcitation and the density functional calculations. Two rotamers ( syn and anti) were identified for m - and o -fluorobenzaldehyde upon the photoexcitation and most of the bands of each rotamer were assigned. It is shown that the formation of the intramolecular C–H⋯F hydrogen bond for the anti rotamer of o -FB results in the shortening of the aldehyde C–H bond length and that the C–F and/or C O bond lengths are shortened for the syn rotamer of o -FB presumably due to the repulsion between the aldehyde O and F atoms.

Fluorescence, fluorescence excitation and absorption spectra of picene have been measured in the vapor phase. It is shown that picene vapor exhibits weak fluorescence from the S 2 (π, π ∗ ) state in addition to strong S 1 (π, π ∗ ) fluorescence. The S 2 /S 1 fluorescence yield ratio is evaluated to be approximately 1.3 × 10 −2 following the excitation into the S 3 state. It is shown that the relative S 2 fluorescence quantum yield increases with increasing excitation energy, while the S 1 fluorescence yield is nearly invariant. Mechanism of the appearance of the S 2 fluorescence of picene vapor is discussed.

Emission and excitation spectra of o -, p - and m -fluorobenzaldehyde ( o -, p - and m -FB, respectively) vapors have been measured at different temperatures and compared to one another. Temperature dependence of the phosphorescence spectrum of m -FB provides the energy difference of 70±20 cm −1 for the two rotational isomers in the T 1 state and 36±20 cm −1 for those in the ground state. It is inferred from semi-empirical SCF-MO calculations and vibrational analysis of the emission spectra that the lower-lying phosphorescence origin at 24,950 cm −1 of m -FB is originating from the anti rotamer, and that the observed emission of o -FB originates from the anti rotamer. The S 1 –T 1 energy separations of o -, p - and m -FB vapors obtained from the temperature dependence of the emission spectrum all agreed well with those obtained spectroscopically.

Fluorescence, fluorescence excitation, and absorption spectra have been measured for diphenylpolyenes with the polyene double bond number (n) from three to seven in solvents with different polarizabilities at room temperature. These polyenes exhibit anti-Kasha S(2) (1 (1)B(u)) fluorescence beside conventional S(1) (2 (1)A(g)) fluorescence in room temperature solution. It is shown that there are two different mechanisms for occurrence of the S(2) (1 (1)B(u)) fluorescence of diphenylpolyenes. S(2) fluorescence occurs through the thermal population of the S(1) state for the shorter diphenylpolyenes (n=3 and 4), while it occurs as prompt S(2) fluorescence due to inefficient S(2)--S(1) internal conversion for the longer diphenylpolyenes (n=6 and 7). With diphenyldecapentaene (n=5), S(2) fluorescence based on both mechanisms is observed depending on the polarizability of the solvent used. The present results provide deeper insight into the mechanism for the occurrence of anti-Kasha S(2) fluorescence of polyenes.

The sodium dodecyl sulfate (SDS)-solubilized freeze fracture replica labeling (SDS-FRL) technique has been successfully applied to a vascular plant, Vigna angularis [Kimura et al. 1999, Plant Cell 11: 2075–2085] and a bacterium, Acetobacter xylinum [Kimura et al. 2001, J. Bacteriol. 183: 5668–5674] for understanding cellulose biosynthesis. However, we do not know yet how many gold particles can be bound with antibodies that label a single rosette or linear TC. We analyzed these techniques from a theoretical background by considering the size of gold particle, primary and secondary antibody, and the rosette and linear TC. The 10 nm gold particles coated with primary and secondary antibodies result in a 30 nm diameter for the gold-conjugated antibody that binds to a rosette TC. Therefore, a rosette TC theoretically could be labeled with, at most, four gold particles and commonly with 1–3 gold particles after the topological consideration of the immunogold labeling of the rosette TC. We interpreted an actual image of freeze-fracture labeling of TCs by comparison with a scale model of the antibody-labeling to a rosette TC. The labeling of linear TCs with the gold-conjugated antibody of c-di-GMP binding protein was quite stable, and 75% of the 277 gold particles were found within 20 nm of the linear row. Labeled TCs with depressions and indistinct particle arrays and non-labeled TCs with distinct particle arrays were observed on the P-fracture face of the outer membrane, suggesting that TCs in A. xylinum are composed of two types of subunits.

The structure of cellulose synthesizing terminal complexes (TCs) has been investigated in different species of ascidians. The linear-shaped TCs consisting of two types of membrane particles were found in four species belonging to two orders including previous data . A relationship between the length of TCs and the size of produced cellulose microfibrils was found within the same order. The density and localization patterns of TCs coincided with the arrangement of cellulose microfibrils in the innermost layer of the tunic, that is outer protective tissue and a major cellulosic component in the ascidians. This suggests that the shape and dimension of the microfibril bundle is influenced by an arrangement of TCs in the epidermal cell membrane.

Emission, excitation, and absorption spectra of diphenyltetradecaheptaene (DP7) have been measured in solvents with different polarizabilities, together with the Raman spectrum at room temperature. DP7 exhibits dual fluorescence from the 2 1Ag(S1) and 1 1Bu(S2) states in room temperature solution. It is shown that the 2 1Ag/1 1Bu fluorescence intensity-ratio varies significantly depending on the solvent polarizability. This observation was interpreted on the basis of the coupling strength between the 2 1Ag/1 1Bu states which is determined mainly by the 2 1Ag–1 1Bu energy separation. Fitting of the spectra with sum of Gaussians reveals a significant difference in Franck–Condon envelop between the 2 1Ag and 1 1Bu fluorescence spectra, which is originating from the large difference in the C–C and C[Double Bond]C stretching mode displacements between the 2 1Ag and 1 1Bu states.

Emission spectra of α,ω-diphenyltetradecaheptaene (DP7) have been measured in polycrystalline n -tetradecane at 77 K. It is shown that DP7 exhibits the dual fluorescence from the 2 1 Ag (S 1 ) and 1 1 Bu (S 2 ) states not only in room temperature solution but also in a rigid matrix at 77 K. The measured fluorescence spectrum at 77 K was compared with the spectrum simulated with sum of Gaussians. The measured and calculated spectra agreed reasonably to each other, and the energy for the 2 1 Ag (S 1 ) to 1 1 Ag (S 0 ) fluorescence origin band was determined to be 16 660 ± 40 cm −1 in n -tetradecane at 77 K.