bluuebunny/crossref_metadata_2025 huggingface dataset:
The Gomphaeschninae (Odonata: Aeshnidae): new fossil genus, reconstructed phylogeny, and geographical history
Authors: WIGHTON DENNIS C. , WILSON MARK V. H.
Published: January 2008

ABSTRACT. Three new species of fossil Anisoptera (dragonflies) are reported from Tiffanian (Late Palaeocene) sediments of the Paskapoo Formation, near Red Deer, Alberta, Canada. The three species are all assigned to the new genus Alloaeschna, which is classified in the subfamily Gomphaeschninae.

Phylogenetic analysis of gomphaeschnine wing venation suggests that the subfamily is paraphyletic, with derived gomphaeschnines such as Boyeria and Linaeschna more closely related to the Brachytroninae and Aeshninae than are other gomphaeschnines. One of the most primitive gomphaeschnines, and the oldest fossil form, is the Jurassic Morbaeschna. Parallelism, convergence and reversal in the evolution of features of the wing venation is common.

The new genus Alloaeschna is at about the same evolutionary grade as the old‐world genus Oligoaeschna and the new‐world genus Gomphaeschna, and is one of the more primitive known members of the Gomphaeschninae. The new species are the first recorded Palaeocene gomphaeschnines and the oldest known gomphaeschnines from the Americas.

Several extant genera have fossil representatives on continents different from those on which they now survive, suggesting repeated crossing of land bridges and/or widespread ancestral species prior to the separation of the continents, and subsequent extinction leading to present relict distributions.
Phlebotomine sandflies (Diptera: Psychodidae) from the Oriental Region
Authors: LEWIS D. J.
Published: January 2008

Abstract. Four new species are described and descriptions of many others revised, and 128 species and two subspecies are now known from the Region. Keys to females of Grassomyia and the Sergentomyia babu series are provided, and the S.arboris series is defined and shown to be an exceptional long‐labrum group. Particulars of 1511 specimens from Indonesia are reported. The vector of kala‐azar around Calcutta is shown to be one of four variants of Phlebotomus argentipes and to have, on average, a slightly longer labrum than the others, more suitable for mammal feeding. The labral length of P.argentipes is, surprisingly, somewhat intermediate between those of most reptile and mammal feeders. Study of both Oriental and other sandflies strongly suggests that in Old and New Worlds the labrum has lengthened in relation to mammal feeding. In the Old World this has been accompanied by advance of the labral main adoral sensilla to produce a morphological, and probably functional, difference between the main Lm/zmam'a‐vector groups of the two hemispheres.
A comparative study of the structures of phylogenetic importance of female genitalia of the Cynipoidea (Hymenoptera)
Authors: FERGUSSON N. D. M.
Published: January 2008

The structure of the female genitalia of the Cynipoidea is described, compared with that of other Hymenoptera and its method of operation discussed. The comparative morphology and the major evolutionary trends within the superfamily are discussed. Cynipoidea have two extraordinary modifications of the female genitalia; the ninth tergite is very long, narrow and centrally bisected so that it apparently forms an extra pair of ovipositor ‘sheaths’ and the ovipositor is so elongate in some families that, in order to accommodate it within the gaster, it forms a complete loop.
Immature stages ofHipparchiaFabricius and the systematics of the‘Satyrusseries» (Lepidoptera: Nymphalidae: Satyrinae)
Authors: GARCÍA‐BARROS ENRIQUE , MARTÍN JOSÉ
Published: January 2008

Abstract.Characters of potential use from the eggs and larvae of four species ofHipparchia(subgeneraHipparchia, Parahipparchia, NeohipparchiaandPseudotergumia) are described. These characters, together with previously published information on larval, pupal and adult morphology, are used to construct a seventy‐one character matrix forHipparchiaand four other genera of the‘Satyrusseries’ (Miller, 1968):Arethusana, Kanetisa, ChazaraandSatyrus. The cladistic relationships among these genera and the relative contribution of adult and immature data sets are discussed. A list of possible synapomorphies of the immature stages of the‘Satyrusseries’ is proposed.
The ant‐lions of southern Africa: genus Pamexis Hagen (Neuroptera: Myrmeleontidae: Palparinae: Palparini)
Authors: MANSELL M. W.
Published: January 2008

Abstract. Pamexis Hagen, 1866, is revised. Myrmeleon luteum Thunberg is designated as type species. A key is provided for the five species comprising the genus. Pamexis luteus (Thunberg, 1784), P.bifasciatus (Olivier, 1811) and P.contaminatus (Hagen, 1887) are redescribed: P.karoo and P.namaqua are new species. All are endemic to the Cape Province of South Africa.
A revision of the genera Dirphys Howard and Encarsiella Hayat (Hymenoptera: Aphelinidae)
Authors: POLASZEK A. , HAYAT M.
Published: January 2008

Abstract. Dirphys and Encarsiella are revised for the world, and include four and six species respectively. Three Dirphys and two Encarsiella species are described as new. Generic diagnoses and keys to world species of Dirphys and Encarsiella are provided, and their biology is reviewed. These genera are related to the large and economically very important genera Coccophagus and Encarsia, which between them contain about 400 currently valid species. Encarsiella was recently synonymized with Dirphys, and both have previously been confused with Coccophagus and Encarsia, adding to the difficulty surrounding the taxonomy of the latter genera. Computerized character analysis based on parsimony supports the reinstatement of Encarsiella as a valid genus and shows relationships between Dirphys, Encarsia and Encarsiella.
Phylogeny of the Dictyoptera
Authors: THORNE BARBARA L. , CARPENTER JAMES M.
Published: January 2008

Abstract. Relationships among six key dictyopteran taxa (Mantodea; Blattodea (excluding Cryptocercidae); Cryptocercidae; Mastotermes darwiniensis, Termopsidae and Kalotermitidae [Isoptera]) are analysed based on seventy morphological, developmental and behavioural characters. The fossil record and the ‘living fossil’ genera Cryptocercus, Mastotermes and Archotermopsis are discussed in detail. Exact analysis of the character state matrix by implicit enumeration (Hennig86) resulted in one cladogram, strongly supporting Blattodea + Cryptocercidae as a sister group to Mantodea, with the Isoptera as a sister group to that complex. Arrangements within the termites are equivocal, with Termopsidae and Mastotermes darwiniensis possible as the relatively most primitive element of Isoptera.
Revision of the myrmicine ant genus Lophomyrmex, with a review of its taxonomic position (Hymenoptera: Formicidae)
Authors: RIGATO FABRIZIO
Published: January 2008

Abstract. The myrmicine ant genus Lophomyrmex is fully revised and transferred from tribe Pheidologetonini to Pheidolini (tribal transfer: Pheidolini, senior synonym of Lophomyrmecini syn.n.). Ten species are recognized, which are placed into two species groups. The quadrispinosus group, characterized by the presence of pronotal teeth or spines, includes birmanus, kali sp.n., opaciceps stat.n. (=javana syn.n.), quadrispinosus (=taprobanae syn.n.) and taivanae stat.n. The bedoti group, in which the pronotum is dorsolateraly marginate, includes ambiguus sp.n., bedoti, longicomis sp.n., lucidus stat.n. and strialulus sp.n. A key to the worker caste is presented and descriptions of known sexual forms are given.
Dasineura ingerissp.n. (Diptera: Cecidomyiidae) onSalix viminalisin Sweden, including comparisons with some otherDasineuraspecies onSalix
Authors: SYLVÉN EDVARD , LÖVGREN LINNÉA
Published: January 2008

Infestations of an undescribed gall midge species were discovered in Southern Sweden in biomass plantations and nurseries ofSalix viminalisL. Terminal leaf buds are damaged and side shoots subsequently develop. This midge,Dasineura ingerissp.n., closely resembles three other species occurring onSalix: D.terminalis(H. Loew) onS.albaL. andS.fragilisL.;D.iteobia(Kieffer) recorded fromS.capreaL. andS.cinereaL.; andD.schreiteri(Stelter) (= comb.n. forRabdophaga schreiteriStelter) originally found as an inquiline in the galls of another gall midge,Dasineura rosaria(H. Loew), onS.repensL. No qualitative differences in morphology were observed between these four gall midge species, but results of morphometric analyses show significant differences between all of them. In oviposition preference trials, which included host plants of all four midge species,D.ingerislaid eggs mainly onS. viminalis, D.schreiteripreferably onS.repens, andD.iteobiaexclusively onS.caprea.In larval performance trialsD.ingerisproduced many galls onS. viminalis, one gall also onS.caprea, but no galls on eitherS.albaorS.repens.
The phylogeny of the Forficulina, a suborder of the Dermaptera
Authors: HAAS FABIAN
Published: January 2008

The phylogeny of the Forficulina (Dermaptera) has been reassessed, examining forty‐eight species and thirty characters, of which thirteen characters of the thorax and wings are described or used for phylogenetic purposes for the first time, whereas the remaining seventeen have been extracted from literature. Examination of the thirty characters demonstrates that only twenty‐three characters are useful for phylogenetic construction. The characters have been analysed with PAUP 3.1 yielding two equally parsimonious trees. The results suggest an exclusion of the ‘Diplatyidae’ (themselves paraphyletic) and the Karschiellidae from the Pygidicranidae and support the separation of the Apachyidae from the Labiduridae. A sister‐group relationship of Anisolabididae and Spongiphoridae is not supported. The monophyly of the (Spongiphoridae (Forficulidae, Chelisochidae)) is supported.
Phylogeny of the families of Scarabaeoidea (Coleoptera) based on characters of the hindwing articulation, hindwing base and wing venation
Authors: BROWNE D. J. , SCHOLTZ C. H.
Published: January 2008

A study is made of the articulation and base of the hindwings of Scarabaeoidea. The survey is based on an examination of over 250 genera from thirteen scarabaeoid families. Relationships among all families of Scarabaeoidea are examined here for the first time. The reconstructed phylogeny shows that the Scarabaeoidea is comprised of three major lineages: a glaresid, passalid and scarabaeid lineage. The glaresid lineage consists only of the Glaresidae. The passalid lineage is comprised of two major lines: a passalid line (containing Passalidae, Lucanidae, Diphyllostomatidae, Glaphyridae, Trogidae, Bolboceratidae and Pleocomidae) and a geotrupid line (containing Geotrupidae, Ochodaeidae, Ceratocanthidae and Hybosoridae). The scarabaeid lineage contains those taxa traditionally included within the Scarabaeidae (Aegialiinae, Aulonocneminae, Aphodiinae, Scarabaeinae, Orphninae, Melolonthinae,Acoma, Chasmatopterinae, Hopliinae, Oncerinae, Rutelinae, Dynastinae, Trichiinae, Cetoniinae and Valginae). Additional evidence, from other character suites, supporting this breakdown of the Scarabaeoidea is given.
XANTHOPHYLLS AND THE HILL REACTION*
Authors: Yamamoto H. Y. , Chichester C. O. , Nakayama T. O. M.
Published: January 2008

The incorporation of oxygen from water enriched in H218O into the leaf xanthophylls during the Hill reaction was investigated. No enrichment was detectable in violaxanthin and neoxanthin. A low incorporation into lutein, which was not dependent on the Hill reaction, was observed.

The results indicate that the epoxy pigments do not function as an oxygen transport system in photosynthesis under the conditions of these experiments.
ON SOME POSSIBILITIES OF PROTECTING CELLS FROM DAMAGING EFFECTS OF ULTRAVIOLET IRRADIATION
Authors: Levin V. L.
Published: January 2008

Abstract. The possibility of increasing the cell resistance to short‐wave u. v. rays has been investigated with some chemicals. Ciliated epithelium cells of gills of pearly mussel Unio crassus Phillipsson have been shown to become more resistant after treatment with 0.25–0.50 per cent solutions of calcium chloride during 24 hr or by 0.001– 0.001 per cent solutions of 2‐benzyl‐benzimidazole during 3–7 days or by 0.0001 per cent solution of 5–6‐di‐methyl‐benzimidazole during 7 days. When irradiated with u. v. light (λ=2537 Å) these cells survive for a longer time than irradiated control cells.
FLASH PHOTOREDUCTION OF FLAVIN MONO NUCLEOTIDE IN NEUTRAL SOLUTIONS ABSOLUTE ABSORPTIVITY OF THE SEMIQUINONE
Authors: Holmström Bertil
Published: January 2008

Abstract— Flash photoreduction of FMN, in aqueous solutions (pH 5–9) leads to the semiquinone (FMNH or FMN). The yield of semiquinone was determined by measuring the amount of leuco‐FMN (FMNH2 or FMNH‐) formed in the subsequent disproportionation. The absorption spectrum of the semiquinone, previously known in relative units, has been converted to an absolute basis. Revised values are given for the protolysis constant for FMNH, for the disproportionation rate, and for the formation constant KF. It is found that KF is much lower for the anionic than for the neutral form of the semiquinone.
PATTERNS OF NUCLEIC ACID AND PROTEIN SYNTHESIS DURING MODIFICATION OF LETHAL ULTRAVIOLET LESION
Authors: Kos E. , Drakulić M. , Brdar B.
Published: January 2008

Abstract— We have shown previously that the viability of E. coli B.U.‐ and E. coli B. try‐could be restored after u.v.‐irradiation if post‐irradiation incubation took place in the presence of chloramphenicol or in the absence of an essential metabolite. By way of contrast, the viability of the u.v.‐irradiated E. coli K.12 meth‐ decreased rapidly during post‐irradiation incubation in the presence of chloramphenicol or in the absence of methionine. During the study of the biosynthesis of nucleic acids and protein in the above strains we made the following observations.

Protein synthesis was permanently inhibited in both amino acid requiring strains during post‐irradiation incubation in the absence of the respective essential metabolite. In E. coli B.U.‐ a slow synthesis of protein could be observed even if post‐irradiation incubation took place in the absence of uracil.

DNA synthesis was completely and permanently inhibited in both E. coli B. try‐ and E. coli K.12 meth‐ during post‐irradiation incubation in the absence of the respective essential amino acid. In E. coli B.U.‐, however, DNA synthesis resumed after a prolonged lag even if the bacteria were incubated after u.v.‐irradiation in the absence of uracil.

RNA synthesis was completely and permanently inhibited in both E. coli B. mutants, the uracil requiring and the tryptophan requiring, if they were incubated after irradiation in the absence of uracil and tryptophan respectively. In E. coli K.12 meth‐ a small amount of RNA is synthesized during post‐irradiation incubation in the absence of the essential amino acid.
MISCHKLONE U.V.‐INDUZIERTER MUTANTEN BEIM PHAGEN KAPPA
Authors: Kaplan R. W.
Published: January 2008

Abstract— Clear‐plaque mutations of phage k of Serratia are induced by extracellular u.v.‐irradiation in a 2–hit process. The 2–hit‐nature cannot be due to induction of one hit in each of the two DNA‐strands since replating the contents of 97 wildtype plaques of u.v.‐survivors (u.v.‐dose 4.5 min) revealed only 1 case of heterozygosity; at least 20 cases would have been expected if phage with 1–hit‐mutations formed phages looking like wildtype. On the other hand, only 1 case of heterozygosity was observed among replatings of 94 c‐mutants induced by the u.v.‐dose 4.5 min (survival 10‐3); most of the plaques contained pure c‐type. The pure c‐mutant clones are very probably due to ‘recessive’ lethal lesions in the nonpremutated DNA‐strand. This is indicated by the dose dependence of the frequency of heterozygotes; at a dose of 3 min u.v. (survival 1.2 × 10‐‐2) 9 heterozygotes were observed among 95 mutants tested. From these numbers the rate of induction by u.v. of the recessive lesions's can be calculated. The data at the higher dose are in satisfactory agreement with the calculated rate. Also other types of plaque mutations (e, t, b) showed heterozygosity. Two cases of abnormal heterozygosity were observed; one contained 2 stable mutant types (c and b), another one wildtype, c‐tm and l‐type.
A STUDY OF PHOTOCHEMISTRY OF FLAVINS IN PYRIDINE AND WITH A DONOR*
Authors: Kurtin William E. , Latino Michael A. , Song Pill‐Soon
Published: January 2008

Abstract— Both anaerobic and aerobic photolysis of riboflavin in pyridine yielded several photoproducts, analogous to the photochemical reaction in aqueous solution. Lumiflavin was also photoreduced in pyridine (an electron donor) without decomposition of the isoall‐oxazine ring Differences in the reactivity of excited singlet and triplet states with respect to formation of photoproducts have been confirmed in pyridine. In the photoreduction of riboflavin by N, N'‐dimethyl‐N‐benzylethylene diamine, an initial rate with a higher relative quantum yield than that of the reaction at a later stage was observed both in water and pyridine. Photolysis in D2O with the donor showed no significant solvent isotope effect. These results strongly suggest that the photolysis of riboflavin in water does not involve the water molecule in the primary photochemical act. A detailed mechanism of flavin photoreaction in water to account for solvent oxygen incorporation into a photoproduct (benzaldehyde) from N, N'‐dimethyl‐N‐benzylethylene diamine has been proposed without involving photochemical splitting of water based on our results and molecular orbital computations.

Preliminary results on the kinetics of free radical decay were obtained using an ESR spectrometer and the significance of the results are discussed.
LA PHOTOOXYDATION DU GROUPE PEPTIDE—I. PROTÉINES FIBREUSES*
Authors: Meybeck A. , Meybeck J.
Published: January 2008

Abstract— The determination of the α‐ketoacids, glyoxylic and pyruvic in partial hydrolysates of fibrous proteins (keratin and fibroin) after exposition to u.v. light has allowed us to suggest a photooxydation mechanism for the α‐aminoacid residues of glycine and alanine in proteins. The primary reaction is believed to be the formation of the peptide radical ‐NH‐CR‐CO‐, and the breakdown of polypeptide chains is explained by the formation of α‐ketoacyl peptide linkages.
ACTION SPECTRA FOR MITOTIC SPINDLE DESTRUCTION AND ANAPHASE DELAY FOLLOWING IRRADIATION OF THE CYTOPLASM WITH AN ULTRAVIOLET MICROBEAM*
Authors: Brown Darrell Q. , Zirkle Raymond E.
Published: January 2008

Abstract— Previous workers have reported that, in a variety of cells, ultraviolet microbeam irradiation of cytoplasm adjacent to the mitotic spindle causes the spindle to diminish or disappear and have postulated that this effect is mediated by a spindle “poison” produced photochemically from a cytoplasmic precursor. In the present work, a microbeam action spectrum for this effect has been obtained to aid in the identification of this mediator material. A small portion of the cytoplasm of Ambystoma(salamander) tissue‐culture cells was irradiated in early metaphase with ultraviolet microbeams of various wavelengths and intensities but of the same diameter (8 μ). Spindle destruction was scored by observing diminution of its image as seen with a polarization microscope. In addition, the time of anaphase was recorded so that an action spectrum for anaphase delay was also obtained. These two action spectra are quite similar and are nearly parallel to the absorption spectrum of a tyrosine‐containing protein. A few proteins are discussed which might mediate this effect.
PHOTODYNAMIC ACTION OF CHEMICALLY RELATED FLAVONES
Authors: Nishie K. , Waiss A. C. , Keyl A. C.
Published: January 2008

Abstract— Flavone, polyhydroxyflavones (apigenin, fisetin, kaempferol, luteolin, myricetin, quercetin, resokaempferol and robinetin), polymethoxyflavones and acetylated and benzylated flavones were tested for photodynamic activity using Tetrahymena pyriformis T as the test organism. Among these compounds, polymethoxyflavones showed the highest order of activity, followed by flavone and then flavone derivatives with OH and OCH3 groups. Resokaempferol was the only active polyhydroxyflavone, the remainder being inactive such as the benzyl‐derivative. The methoxyl group in the 5–position and an increase in number of methoxyl groups from one to three in the phenolic portion of the flavonoid tended to decrease photodynamic activity. Tetrahymena killed photodynamically by polymethoxyflavones were morphologically altered by blister‐like blebs. Polymethoxyflavones showed the lowest cytotoxicity and the greatest photodynamic activity among those flavonoids tested. The majority of the favonoids in this series have absorption spectra in the 320–370 nm region.
FLUORESCENCE DEPOLARIZATION BY LIGHT‐SCATTERING IN TURBID SOLUTIONS
Authors: Teale F. W. J.
Published: January 2008

Abstract— The effect of light‐scattering on the fluorescence polarization of solutions has been investigated both theoretically and empirically. The criteria by which turbidity depolarization may be recognised are described, and differentiated from those which characterise depolarization through optical rotation or birefringence. These criteria have been used to confirm that the fluorescence depolarization which accompanies actomyosin formation originates in increased light‐scattering rather than a real change in relaxation time.
PHOSPHORESCENCE SPECTRA OF α‐DIKETONES IN LOW TEMPERATURE GLASSES
Authors: Almgren Mats
Published: January 2008

Abstract— The emission properties of o‐anisil, p‐anisil, benzil, and biacetyl in glasses containing varying proportions of isopropanol have been studied. The different kinds of phosphorescence spectra observed are proposed to be due to triplet states of different conformations and to triplet states of solvated species or other compounds formed by a reaction of the α‐diketones with isopropanol.
A MODEL FOR BIOLOGICAL QUANTUM CONVERSION INVOLVING THE PHOTOOXIDATIVE DEPHOSPHORYLATION OF MENADIOL DIPHOSPHATE
Authors: MOORE THOMAS A. , SONG PILL‐SOON
Published: January 2008

Abstract— The mechanism of the photooxidative dephosphorylation of menadiol diphosphate appears to be invariant with respect to three sensitizers used; namely, riboflavin, biacetyl, and menadiol diphosphate itself. The mechanism involves triplet energy transfer from the sensitizers to oxygen to yield singlet oxygen which oxidizes menadiol diphosphate. The photolysis of menadiol diphosphate in acetic acid has resulted in formation of acetyl phosphate, as determined by paper chromatography. Therefore, we have demonstrated the feasibility of our model for converting light energy into chemical potential (‘high‐energy’ phosphate bond energy or group transfer potential) in the form of acetyl phosphate.
INTERACTIONS BETWEEN LIGHT AND CIRCADIAN RHYTHMS IN PLANT PHOTOPERIODISM*,†
Authors: HOSHIZAKI TAKASHI , HAMNER K. C.
Published: January 2008

Abstract— The timing mechanism in plant photoperiodism seems to involve two endogenous circadian rhythms: a light‐on (dawn) rhythm and a light‐off (dusk) rhythm. Following a period of darkness light may affect flowering without affecting the rhythms, or it may affect flowering by rephasing the rhythms. A hypothesis is presented concerning the mechanism of the interaction between illumination and endogenous rhythms based upon correlations between leaf movements and flowering responses in various photoperiodic treatments. The possible role played by phytochrome in the response is considered in relation to the effects of light quality on the responses.
MECHANISMS IN THE QUANTUM YIELD OF CYPRIDINA BIOLUMINESCENCE*
Authors: SHIMOMURA OSAMU , JOHNSON FRANK H.
Published: January 2008

Abstract— –The influence of temperature, pH, salts, and reactant concentrations on the biolumin‐escent oxidation of Cypridina luciferin catalyzed by Cypridina luciferase indicates a highest quantum yield φ (einsteins per mole of luciferin oxidized) of 0.31 in H2O, or 0.33 in 99% D2O. With the aid of data on fluorescence of the light‐emitting oxyluciferin‐luciferase complex, and of oxyluciferin in diglyme, partial explanations are suggested for the observed variations in φ, including the relatively low φ, of 0.03 for chemiluminescence of luciferin in organic solvents, wherein a different pathway of luciferin degradation, as indicated by chromatographic evidence, results in much less population of the excited state.
INTERACTION BETWEEN TYROSINE AND DIVALENT SULFUR IN FLUORESCENCE QUENCHING AND IN THE PHOTOCHEMISTRY OF RIBONUCLEASE
Authors: ARIAN SHULAMIT , BENJAMINI MIRA , FEITELSON JEHUDA , STEIN GABRIEL
Published: January 2008

Abstract— –Ribonuclease is inactivated in aqueous solution by u.v. light through different mechanisms according to whether divalent sulfur or aromatic amino acids are the primary light absorbers. At 284 nm, absorbed mainly by tyrosine, the presence of O2 inhibits photoinactivation and H2S formation, but does less so at 254 or 313 nm. Based on data with model substances containing disulfide groups a mechanism is indicated in which excited tyrosine is quenched through electron transfer to adjacent divalent sulfur within the protein. Disulfide compounds are shown to be very efficient quenchers of tyrosine fluorescence.
SOME CHEMICAL AND PHYSICAL PROPERTIES OF A BACTERIAL REACTION CENTER PARTICLE AND ITS PRIMARY PHOTOCHEMICAL REACTANTS*
Authors: FEHER G.
Published: January 2008

Abstract— A photochemically active protein‐chlorophyll complex (i.e. reaction center particle) has been isolated from Rhodopseudomonas spheroides R‐26. The isolation and purification procedure is outlined and some of the chemical and physical properties of the complex (e.g. amino acid composition, metal content, molecular weight) are presented. Two distinct ESR signals have been observed. They are attributed to the primary oxidation‐reduction couple. The experimental evidence which shows that the narrow (g= 2.0026) signal is due to a bacterio‐chlorophyll free radical is reviewed. The possibility that the broad ESR signal is due to iron is discussed.
EFFECTS OF SENSITIZED AND UNSENSITIZED LONGWAVE U.V.‐IRRADIATION ON THE SOLUTION PROPERTIES OF DNA
Authors: ZIERENBERG B. E. , KRÄMER D. M. , GEISERT M. G. , KIRSTE R. G.
Published: January 2008

Abstract— Two types of photoreactions occur in DNA irradiated in aqueous systems with longwave u.v.‐light (Λ > 295 nm), namely, (a) thymine dimerization, and (b) single‐ and double‐strand breakage of the sugar phosphate backbone; these two reactions are unrelated. The presence of acetophenone as a photosensitizer caused an increase in dimerization by a factor of 16, and an increase in single‐strand breaks by a factor of 4. The number of thymine dimers per single‐strand break is about 100 in the sensitized and 25 in the unsensitized reaction. The alteration of the radius of gyration of DNA molecules is that expected by the degradation observed. At the same time the change in hyperchromicity is very small. Therefore as far as can be detected by these methods of investigation the gross conformation of the DNA double helix is stable against thymine dimerization.
EFFECTS OF HIGH PRESSURE ON PHOTOCHEMICAL REACTION CENTERS FROM RHODOPSEUDOMONAS SPHEROIDES*
Authors: CLAYTON R. K. , DEVAULT D.
Published: January 2008

Abstract— Photochemical reaction centers from Rhodopseudomonas spheroides were subjected to pressures ranging from 1 to 6000 atm. Optical absorption, fluorescence and photochemical activities were studied under these conditions.

Absorption spectra showed bathychromic shifts of the long‐wave bands attributed to bacteriopheophytin and bacteriochlorophyll (the latter as P800 and P870).

The quantum efficiency of photochemical oxidation of P870 was diminished at high pressure. The quantum yield of P870 fluorescence showed a parallel decline, as if high pressure introduced a quenching process that competed with both photochemistry and fluorescence. The original efficiencies were largely restored when the pressure was returned to 1 atm.

The efficiency of oxidation of mammalian cytochrome c, coupled to the photochemical oxidation of P870 in reaction centers, was lowered by high pressure. This effect was more pronounced than the effect on P870 oxidation, and was irreversible.

The kinetics of recovery of P870 following its photochemical oxidation showed effects of high pressure. The main effect was the appearance, at high pressure, of slow recovery suggesting the trapping of electrons. This effect was partly irreversible.
STUDIES ON THE CHEMILUMINESCENCE OF LUMINOL IN DIMETHYLSULFOXIDE AND DIMETHYLSULFOXIDE‐WATER MIXTURES*
Authors: GORSUCH J. D. , HERCULES D. M.
Published: January 2008

Abstract— The absorption, fluorescence, and chemiluminescence (CL) characteristics of luminol have been studied in basic dimethylsulfoxide (DMSO) and various basic DMSO — water mixed solvents. It has been shown that the luminol dianion can be produced quantitatively in carefully deoxygenated ‘dry’ DMSO using potassium t‐butyl alcoholate (BTO) as the base. A direct correlation has been found between the intensity of CL and the concentration of luminol dianion, Indicating that the dianion is the reactive species in the chemiluminescent reaction in DMSO. Increasing concentrations of water in the mixed solvents greatly reduced the CL intensity because of the decrease in luminol dianion concentration. Solvent effects on the fluorescence of 3‐aminophthalic acid samples was noted and identified. Chemiluminescent spectra of luminol were run as a function of solvent composition, and compared with fluorescence spectra in the same media. The need for correcting these spectra for comparison was noted. Stopped flow kinetic studies were run in DMSO and DMSO‐water mixtures. These data can be interpreted on the basis of two second‐order steps and one first‐order step in the reaction. The first‐order step is probably last and probably arises from decomposition of a ‘peroxy’ intermediate. The rate constant for this step is k= 1·2±0·3×10‐1 sec‐1.
PHOTOCHEMICAL DECARBOXYLATION OF AMINO ACIDS IN THE PRESENCE OF METAL IONS
Authors: POUPKO R. , ROSENTHAL I. , ELAD D.
Published: January 2008

Abstract— An electron‐spin‐resonance study of the radicals produced by ultraviolet irradiation of amino acids in the presence of transition metal ions at low temperature has been carried out. For the monocarboxylic acids, the photosensitized irradiation resulted in loss of carbon dioxide, which led to the formation of free radicals of the type H3ŃR1R2. When the amino acid contained two carboxylic groups, e.g. aspartic acid, decarboxylation took place at the position remote from the amino group. When the odd electron is localized at the carbon atom β to the amino group, e.g. β‐alanine and aspartic acid, it was stable enough to be detected at room temperature.
RED LIGHT‐INDUCED ACCUMULATION OF EUGLENA GRACILIS
Authors: Checcucci A. , Colombetti G. , Carratore G. Del , Ferrara R. , Lenci F.
Published: January 2008

Abstract— It has been shown that green cells of Euglena gracilis accumulate under red light. The action spectrum of this response has been determined. Its shape and the results of regreening experiments clearly indicate a role of chlorophyll. The quenching effect of chlorophenyl–dimethylurea and NH2OH demonstrate that this cell accumulation is not directly light‐induced, as in the case of phototaxis, but is due to an effect of oxygen, the evolution of which is stimulated by light.
X‐RAY SENSITIVITY OF PHOTOSYNTHETIC AND REPRODUCTIVE SYSTEMS IN CHLORELLA
Authors: Nokes M. A. , Simic M.
Published: January 2008

Abstract— Some effects of X rays on the green alga Chlorella pyrenoidosa have been investigated by measurements of survival and oxygen‐evolving capability. Photosynthetic oxygen evolution at light saturation and endogenous respiration showed the same radiation sensitivity, and these two processes were about 40 times more resistant to X‐ray‐induced inactivation than survival. Responses of cells receiving doses in excess of 200krad are in agreement with the existence of two photosystems, photoreaction II being apparently more sensitive to X rays than photoreaction I.
PHOTOSENSITIZED HERBICIDAL ACTION
Authors: Zweig A. , Nachtigall G. W.
Published: January 2008

Abstract— The herbicidal action produced by the colorless hydrocarbon fluoranthene sprayed on the leaves of growing plants does not occur when UV radiation is removed from the light to which the plants are exposed. If the UV component of the light under which the plants are grown is augmented, the herbicidal effect of fluoranthene is increased. The mechanism of this photodynamic action is discussed.
SENSITIVITY OF STRAINS OF ESCHERICHIA COLI DIFFERING IN REPAIR CAPABILITY TO FAR UV, NEAR UV AND VISIBLE RADIATIONS*
Authors: WEBB ROBERT B. , BROWN MICKEY S.
Published: January 2008

Abstract— In stationary phase, strains of Escherichia coli deficient in excision (B/r Her) or recombination repair (K.12 AB2463) were more sensitive than a repair proficient strain (B/r) to monochromatic near‐ultraviolet (365 nm) and visible (460 nm) radiations. The relative increase in sensitivity of mutants deficient in excision or recombination repair, in comparision to the wildtype, was less at 365 nm than at 254 nm. However, a strain deficient in both excision and recombination repair (K12 AB2480) showed a large, almost equal, increase in sensitivity over mutants deficient in either excision or recombination repair at 365 nm and 254 nm. All strains tested were highly resistant to 650 nm radiation. Action spectra for lethality of strains B/r and B/r Her in stationary phase reveal small peaks or shoulders in the 330–340, 400–410 and 490–510 nm wavelength ranges. The presence of 5μg/ml acriflavine (an inhibitor of repair) in the plating medium greatly increased the sensitivity of strain B/r to radiation at 254, 365 and 460 nm, while strains E. coli B/r Her and K12 AB2463 were sensitized by small amounts. At each of the wavelengths tested, acriflavine in the plating medium had at most a small effect on E. coli K.12 AB2480. Acriflavine failed to sensitize any strain tested at 650 nm. Evidence supports the interpretation that lesions induced in DNA by 365 nm and 460 nm radiations play the major role in the inactivation of E. coli by these wavelengths. Single‐strand breaks (or alkali‐labile bonds), but not pyrimidine dimers are candidates for the lethal DNA lesions in uvrA and repair proficient strains. At high fluences lethality may be enhanced by damage to the excision and recombination repair systems.
THE SUNBURNING ULTRAVIOLET METER: DESIGN AND PERFORMANCE
Authors: Berger D. S.
Published: January 2008

Abstract— A meter for measuring the skin sunburn effectiveness of a light source is being used in an extensive network to provide solar data for correlation to skin cancer incidence. The solar radiation measured also affects a wide variety of organisms. The intensity of this band of radiation is also strongly affected by ozone concentration so that the output correlates with ozone thickness.

The meter spectral response is essentially the excitation spectrum of magnesium tungstate phosphor which is similar to the erythema action spectrum (EAS). In addition to the waterproofed, dose reading embodiment, a cheaper, easily transportable, batteryless, intensity reading meter with the same spectral response has been developed.

The deviation of any sunburn meter from the ideal erythema action spectrum can be calculated by convolution of a series of solar spectra against each of the two response spectra. Plotting the change in output against the change in input results in straight lines. Either log‐log coordinates are required, or, as is done here, decibels can be used on linear coordinates. The angle between the straight lines is taken as the error. An error angle of 6.5° is calculated for the present meter.
PHOTOCHEMICAL HYDROXYLATION OF 7,8‐DIMETHYLALLOXAZINE (LUMICHROME)‐A FLASH PHOTOLYSIS STUDY
Authors: Düren R. R. , Dekker R. H. , Beek H. C. A. Van , Berends W.
Published: January 2008

Abstract—Flash photolysis experiments on the hydroxylation of lumichrome (L) in aqueous 0.5 M H2SO4solution in the presence of O2or Ni2+as triplet quenchers and quantum yield measurements confirm the assignment of the photoreactive species to the protonated form of the excited singlet state. A mechamism concerning the photochemical step is proposed, accounting for the formation of protonated 9‐hydroxy‐5,10‐dihydrolumichrome (LOH3+). This primary stable photoproduct was characterized by spectral and kinetic data. The dark reactions originating from LOH3+were investigated, and data regarding the successive steps are presented. The reaction LOH3+L→ LO + LH3+is demonstrated to be a two‐electron reduction. The rate constant for the reaction of LH2+with O2is much larger than that for the oxidation of LH3+by oxygen.
ORCADIAN OSCILLATORS AND PHOTORECEPTORS IN THE GASTROPOD, APLYSIA*
Authors: Lickey Marvin E. , Block Gene D. , Hudson David J. , Smith John T.
Published: January 2008

Abstract— The sea slug, Aplysia, is a useful model system for research on the neurophysiology of circadian integration. The animal contains several circadian oscillators and several photoreceptors. Each eye contains a circadian oscillator as well as photoreceptors. The ocular oscillators can be entrained by extraocular photoreceptors as well as their own ocular photoreceptors. The abdominal ganglion probably contains another oscillator but it has been much more difficult to manipulate in the laboratory than have the oscillators in the eyes. There is also a circadian rhythm in overt behavioral activity. This rhythm is controlled in part by extraocular oscillators and extraocular photoreceptors and in part by the eyes. In exerting their influence on the behavioral rhythm, the eyes appear to act in the capacity of oscillators and not merely as photoreceptors. Although neurons in the retina have neurosecretory morphology, the entire influence of the eyes on the behavioral rhythm appears to be mediated by nerve signals which travel in the optic nerve. As yet there is no evidence to suggest that any two oscillators in Aplysia are internally coupled. There is also no evidence yet for hormonal coupling between photoreceptors and oscillators or between oscillators and rhythmic outputs.
PHOTOCHEMISTRY OF FLAVINS. II. PHOTOPHYSICAL PROPERTIES OF ALLOXAZINES AND ISOALLOXAZINES
Authors: Grodowski M. S. , Veyret B. , Weiss K.
Published: January 2008

Abstract. Pulsed laser photolysis at 347nm has been used to study the transient spectroscopy of alloxazine, lumichrome, lumiflavin, and riboflavin in acidic (pH 2.2) aqueous solution and in ethanol. Intersystem crossing quantum yields (φISC) were determined by a modification of the comparative laser excitation method which utilizes the variation of the triplet yield with intensity in conjunction with a kinetic model for the various photophysical and photochemical processes occurring during the pulse. Fluorescence quantum yields and lifetimes are also reported. Correction for quenching of the excited singlet state by H+ ions shows that, in neutral aqueous solution, intersystem crossing for flavins is an efficient process (φISC˜ 0.7) which, in conjunction with fluorescence, accounts for the fate of all absorbed photons. For alloxazine (φISC˜ 0.45) and lumichrome (φISC˜ 0.7) the results are more difficult to interpret owing to interconversion between alloxazine and isoalloxazine structures in the singlet excited state. For all four compounds, the quantum yield of products derived from the singlet excited state is estimated as ˜0.04. There is evidence of biphotonic product formation at high laser energies. In ethanol, where φISC for lumichrome is about twice that of lumiflavin, internal conversion between the excited singlet and ground states appears to be a significant process. Complete triplet‐triplet absorption spectra in the region 260–750nm are reported. For lumichrome at pH 2.2 there is spectral evidence for isomeric triplet states which appear to be in equilibrium.
THE FUNCTION OF PHYTOCHROME IN THE NATURAL ENVIRONMENT—II. THE INFLUENCE OF VEGETATION CANOPIES ON THE SPECTRAL ENERGY DISTRIBUTION OF NATURAL DAYLIGHT
Authors: Holmes M. G. , Smith Harry
Published: January 2008

Abstract— Qualitative changes in the spectral energy distribution (SED) of natural daylight within the 400–800 nm wavelength band have been followed within a wheat canopy. Selective attenuation of radiation by the canopy caused large decreases in the blue and red wavebands and, to a lesser extent, the green; far‐red was largely transmitted. This resulted in a decrease in the red:far‐red ratio from the values observed in natural daylight.

The spectral energy distribution below the canopy was found to be partially dependent on solar elevation and sky condition; it was also dependent on the age, height, leaf area index and chlorophyll content of the crop. The possible ecological significance of the wide variety of spectral energy distributions which have been observed are discussed in relation to phytochrome function.
ORGANIC PHOTOCHEMISTRY—XV. APPLICATIONS OF PHOTOCYCLOADDITION REACTIONS IN NATURAL PRODUCT SYNTHESES*,†
Authors: Dilling Wendell L.
Published: January 2008

Abstract— Photocycloaddition reactions which have been employed as one of the steps in the total/ synthesis of natural products are reviewed. The utility of the cycloadducts in these syntheses is also discussed.
FLUORESCENCE AND ELECTROGENERATED CHEMILUMINESCENCE STUDIES OF SEVERAL DIMETHYL‐SUBSTITUTED BENZO[a]PYRENES
Authors: Park Su‐Moon
Published: January 2008

Abstract— Absorption spectra, molar absorptivities, fluorescence spectra and fluorescence quantum yields of five dimethylbenzo[a]pyrenes (DMBP) in benzene solutions at room temperature are reported. Electrogenerated chemiluminescence (ecl) spectra and the relative eel intensities of these compounds to that of 9,10‐diphenylanthracene in the 1:1 acetonitrile‐benzene mixed solvent with tetra‐n‐butyl‐ammonium perchlorate as a supporting electrolyte are also reported. Both fluorescence quantum yield and ecl intensity studies show that the vicinal dimethyl substitution lowers the fluorescence and eel efficiency, and this effect is more pronounced in a compound whose K‐region is blocked. The compounds in which the L‐region is blocked showed much higher fluorescence and eel efficiency. The fluorescence of DMBP molecules is quenched by the donor molecule, tri‐p‐tolylamine with a diffusion controlled rate to form an emitting exciplex. The cation radical of TPTA and the radical anion of the DMBPs are shown to form an exciplex efficiently by the eel experiments. Both quenching and eel results indicate that all DMBPs studied here are good acceptors.
REACTIONS OF O‐2, H2O2 AND OTHER OXIDANTS WITH SULFHYDRYL ENZYMES‡
Authors: Armstrong David A. , Buchanan John D.
Published: January 2008

Abstract— The inactivation of a number of sulfhydryl enzymes by H2O2. OH and O‐2 is discussed. and the efficiencies of inactivation for the free radicals are compared with those of halide radicals. The enzymes with essential acyl‐binding SH groups (papain and GAPDH) exhibit a higher sensitivity to inactivation by O‐2 and H2O2 than those with “unactivated” SH groups (LDH and ADH). The sulfenic acid derivatives from the reactions of papain and GAPDH with H2O2 are repairable by RSH molecules, the rates of repair depending on the nature of the R group.

Comparisons of rate constants show that competitive scavenging by RSH must be a very important mechanism for the protection of sensitive SH‐containing proteins against OH, and for papain in oxygen‐free solutions the efficiency of this protection increased in the order GSH < PenSH < CysSH < dithiothreitol. On the other hand, catalase and superoxide dismutase are more effective than RSH compounds in rendering protection against H2O2 and O‐2. In fact in oxygen‐containing systems the effects of RSH are highly complex, because the OH‐ and/or O‐2‐initiated chain oxidation of these molecules produces reactive species, which may inactivate essential SH groups. Experiments with papain showed that the yields and nature of the RSH‐derived species depended on the structure of the R group. Also, very large yields of papain Cys25SSR were produced from the reactions of the radicals and H2O2. In effect, it is apparent that under certain conditions the oxidation of “activated” SH groups of important target molecules could become coupled to the OH or O‐2 ‐initiated oxidation of RSH molecules. This should be taken into account in assessing the overall effectiveness of RSH compounds as cellular protectors.
STUDIES ON THE PHOTOTOXICITY OF COUMARIN DERIVATIVES — I. PHOTOCYCLODIMERIZATION OF 5,7‐DIMETHOXYCOUMARIN
Authors: Shim Sang Chul , Choi Kwan Yong , Song Pill‐Soon
Published: January 2008

Abstract— 5,7‐DimethoxJtcoumarin (DMC) dimerizes through the C4‐photo‐cycloaddition of 3,4‐double bonds to form a syn head‐to‐tail dimer on direct irradiation (Λ≥ 300 nm) in acetonitrile or benzene solution. The quantum yield of the photocyclodimerization in acetonitrile is 0.068 which is greater than that of coumarin.

In the presence of triplet sensitizers such as benzophenone, 5,7‐dimethoxycoumarin forms an anti dimer with the quantum yield greater than 0.08. The structure of the photodimers has been elucidated by IR, UV, NMR, and mass spectrometry. The results of luminescence studies, triplet quenching and sensitization revealed that the syn head‐to‐tail dimer was formed via an excited singlet precursor, while the anti dimer was formed via the excited triplet state.
MEMBRANE POTENTIAL AND MICROSECOND TO MILLISECOND DELAYED LIGHT EMISSION AFTER A SINGLE EXCITATION FLASH IN ISOLATED CHLOROPLASTS
Authors: Jursinic P. , Govindjee  , Wraight C. A.
Published: January 2008

Abstract— The effect of light‐induced and salt‐jump induced membrane potential on microsecond and millisecond delayed light emission from chloroplasts, following a single 10 ns flash, have been studied. Microsecond delayed light emission is shown to be independent of the membrane potential contrary to proposals that the activation energy for delayed light emission can be modulated by transmembrane electric fields. This result is discussed in terms of the possible origin of this short‐lived emission. Millisecond delayed light after a single excitation flash is enhanced by membrane potential only if a proton gradient is present. By measuring changes in ms delayed light caused by simultaneous injection of KC1 and Na‐benzoate (which creates a proton gradient) in the presence of valinomycin, the light‐induced potential generated across the thylakoid membrane by a single excitation flash was calibrated and found to be 128 ± 10 mV in agreement with the recent measurements of Zickler and Witt (1976) based on voltage‐dependent ionophores. It is concluded that the secondary charges that give rise to ms delayed light, after a single flash, do not fully span the membrane.
REGULATION OF CHLOROPLAST DEVELOPMENT BY RED AND BLUE LIGHT
Authors: Buschmann C. , Meier D. , Kleudgen H. K. , Lichtenthaler H. K.
Published: January 2008

There are specific differences between red and blue light greening of etiolated seedlings of Hordevm vulgare L. Blue light results in a different prenyl lipid composition of chloroplast as compared to red light of equal quanta density. This is documented by a much higher prenylquinone content, higher chlorophyll a/b ratios, and lower values for the ratio xanthophylls to carotenes (x/c). The photosynthetic activity of “blue light” chloroplasts (Hill reaction) is higher than that of “red light” chloroplasts. These differences in prenylquinone composition and Hill‐activity are associated with a different ultrastructure of chloroplasts. “Red light” chloroplasts exhibit a much higher grana content than “blue light” chloroplasts. The difference in thylakoid composition, photosynthetic activity and chloroplast structure found between blue and red light greening are similar to those found between sun and shade leaves and those between plants grown under high and low light intensities.