bluuebunny/crossref_metadata_2025_split huggingface dataset:
A morphological and taxonomic study of first instar larvae of Aphidiinae (Hymenoptera: Braconidae)
Authors: O'DONNELL D. J. 
Published: January 2008

Abstract The morphology and taxonomy of first instar larvae of twenty‐five species from eleven genera of primary aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) were examined. A detailed comparative study of the external morphology of aphidiine larvae was carried out, using SEM and phase contrast microscopy, in which many new characters were discovered. Theories concerning the possible functions of various structures are discussed.Descriptions of the first instars of the genera examined and keys for their identification are included.The clsssification of Aphidiinae, based on larval characters, was examined using multivariate analysis. This showed that Aphidius, Diareretiella, Lysiphlebus and Pauesia are very similar to each other and have how percentage similarity values to other Aphidiinae. Ephedrus and Praon, however, show great similarity to each other. These results contradict the classification based on adult characters, proposed by Mackauer (1968). Evidence to support full generic status for Falciconus, Binodoxys and Trioxys in proposed.
Morphological variation in Gyrinus sericeolimbatus Rég. in New Guinea and description of a new Gyrinus species (Coleoptera: Gyrinidae)
Authors: SVENSSON BO W. 
Published: January 2008

Abstract. Samples of Gyrinus sericeolimbatus from twenty‐six localities in New Guinea vary greatly in metric body characters as well as in elytral reticulation patterns. The variation is smaller within than between populations. Although the characters of adjacent populations are usually similar, certain proximate populations exhibit significant differences, probably resulting from some kind of dispersal barrier. Similarities between populations at comparable latitudes suggest that some of the morphological variation is altitude‐related. In addition, evidence is found for habitat‐related morphological differentiation. Changes in phenotypes in response to possible environmental factors in ontogeny and constraints imposed by various selection pressures are discussed.A new species, G.brincki sp.n., from western New Guinea is described.
A cladistic analysis of wax scales (Hemiptera: Coccoidea: Coccidae: Ceroplastinae)
Authors: QIN TING‐KUI , GULLAN PENNY J. 
Published: January 2008

AbstractSeven genera of wax scales (Ceroplastinae) have been accepted as valid by some or all coecidologists:CeroplastesGray,CeroplastidiaCockerell,CerostegiaDe Lotto,GascardiaTargioni Tozzetti,ParacerostegiaTang,VinsoniaSignoret andWaxiellaDe Lotto. The status of most these genera is controversial. The present study reviews the taxonomic history of wax scales and presents a new classification based on cladistic analysis of morphological data from the adult females of eighty‐three species. The analysis indicates that the wax scales form a monophyletic group, thatWaxiellais monophyletic but thatCeroplastidia, GascardiaandVinsoniaare not, and fails to support the generic status ofCerostegiaandParacerostegia.Apart from the type species ofVinsonia, which was placed as a sister to the rest of wax scales, the only other species assigned toVinsoniaand most species of all other genera fall withinCeroplastesin the cladogram. Recognition of any of these genera rendersCeroplastesparaphyletic or polyphyletic. Thus, cladistically, the wax scales should be classified into one genus,Ceroplastes.
STUDIES ON THE LOCALIZATION, FUNCTION, AND FORMATION OF THE CAROTENOID PIGMENTS OF A STRAIN OF MYCOBACTBRIUM MARINUM
Authors: Mathews M. M. 
Published: January 2008

Abstract— Aninvestigation was made of the location, function and characteristics of production of carotenoid pigments of a strain of Mycobacterium marinum, an organism which produces its pigments only when exposed to light.It was found that light‐grown cells of this organism contain only one pigment. The intracellular location of this pigment was found to be the cell envelope. The pigment was found to be capable of protecting the cells against lethal photo‐oxidations mediated by the dye, toluidine blue.These studies also revealed that in dark‐grown cells exposed to light, pigment production occurred after a short lag and then remained constant during logarithmic growth. Pigment was produced by starved cells, but to a lesser degree than son‐starved cells; the addition of a carbon or nitrogen source to starved cells increased pigmentation to the level in non‐starved cells. Pigmentation did not occur in the absence of oxygen. Cells exposed to light at 4°C were not pigmented immediately after exposure, but became so if incubated at 30°C. Production of pigment was found to obey the Bunsen‐Roscoe reciprocity law. The determination of an action spectrum for the production of pigment indicates that maximum pigment productiion occurs in the vicinity of 410 and 439 mµ, with smaller maxima in the vicinity of 502, 528 and 560 mµ.
THE PHOTOCHEMISTRY OF THYMINE AND BROMOURACIL IN VIVO
Authors: Smith Kendric C. 
Published: January 2008

Abstract. A study of the relative sensitivity of bromouracil and thymine to photochemical alteration (2537Å) when incorporated into the DNA of bacterial cells has led to the conclusion that bromouracil is about twice as reactive as thymine. This offers a chemical basis for the sensitization of bacteria to ultraviolet light by incorporated bromouracil.Bromouracil forms at least five photoproducts in vivo. The relative proportions of these several photoproducts is significantly different in E. coli B/r and Enterococcus Stei. Uracil is the chief photoproduct of bromouracil in Enterococcus Stei but in E. coli B/r the major photo‐product (which is a minor product in Enrerococcus Stei) is as yet unidentified.Preliminary data on the five to nine decomposition products of the dimer of bromouracil and the mixed dimer of uracil and bromouracil (produced in irradiated frozen solution) have suggested a tentative explanation for the differences in products in the two organisms. The results for Enterococcus Stei appear consistent with the asumption that the major photo‐product of bromouracil is the dimer and this then decomposes to yield mainly uracil (as it does in vitro). E. coli B/r takes up less bromouracil and the photoproducts formed resemble more closely those found for the in vitro decomposition of the bromouracil‐uracil dimer. These results suggest that the primary photoproduct of bromouracil in E. coli B/r may be either a mixed dirner (intrastrand) with cytosine (with the subsequent deamination of the cytosine) or an interstrand crosslink with either bromouracil or cytosine.Thymine forms at least four photoproducts other than the dimer. Two of these photoproducts are significantly elevated in that portion of the bacterial DNA that is rendered non‐extractable by detergent after ultraviolet irradiation (remains associated with protein) and are also found in irradiated poly‐dAT.From the rate of formation of thymine dimers in irradiated (2537Å) E. coli B/r it can be calculated that approximately 1 erg/mm2 produces one thymine dimer.
ELECTRON SPIN RESONANCE OF TRIPLET STATES AND FREE RADICALS APPEARING IN PORPHYRINS, AROMATIC AMINO‐ACIDS AND PROTEINS UNDER THE EFFECT OF LIGHT
Authors: Azizova O. A. , Gribova Z. P. , Kayushin L. P. , Pulatova M. K. 
Published: January 2008

Abstract— The electron paramagnetic resonance (EPR) of the triplet excited state of solutions of a series of porphyrins and aromatic amino‐acids has been studied at 77°K. It has been shown that for some of the compounds it is possible to observe EPR for transitions with δM=±1, ±2.It has been shown that photoreactions in solid solutions of porphyrins and aromatic amino‐acids proceed through the triplet excited state.Reactions of photosensitized deamination of aliphatic amino‐acids in solid aqueous solutions at 77°K by aromatic compounds have been studied.
PHOTOCHEMINE ANOMALER NUCLEINSÄUREBAUSTEINE‐I. PHOTODEGRADATION VON AZAPYRIMIDINEN UND AZAPURINEN
Authors: Kittler L. , Berg H. 
Published: January 2008

Abstract— The photodegradation of Azapyrimidines and Azapurines by intensive u.v.‐irradiation has been investigated and compared with some pyrimidines and purines. The main output at 253.7 nm of our special low pressure mercury lamp which surrounded the cylindrical cell, was 6.7 times 10‐6 einstein cm‐2 min‐1. The concentrations (5 times 10‐4 M in phosphate buffer pH 7) of the irradiated substances decrease exponentially with half‐lifetimes between 2 and more than 60 min. In contrast to the very high stability of adenine, 8‐Azaadenine was degradated in a few minutes only. 6‐Azauracil also reacts rapidly in its excited state with solvent and the first stable photoproduct one can enrich is its hydratation product. By heating of the hydratation product the 6‐Azauracil was regenerated. The changes in stability:Azauracil > UracilAzaadenine < AdenincAzaguanine < Guanineare of great interest in the field of photomutagenis of DNA, modifies by azabases.
A FLASH‐PHOTOLYSIS INVESTIGATION OF FLAVIN PHOTOSENSITIZATION OF PURINE NUCLEOTIDES
Authors: KNOWLES A. , ROE E. M. F. 
Published: January 2008

AbstractEvidence for the existence of a reactive triplet excited state of lumiflavin has been obtained by the flash‐photolysis technique. The triplet state is formed in high yield on the irradiation of flavin solutions in water or chloroform by visible light, and it has been demonstrated that it can transfer its energy to a second molecular species. The flavin‐sensitised oxidation of two purine nucleotides, adenylic and guanylic acids, has been studied by flash‐photolysis and by long‐term irradiation, and the results suggest a triplet‐triplet mechanism for the transfer of energy from the excited flavin to the nucleotide.Approximate absorption spectra of the triplet state and of a semiquinone of the flavin have been calculated from the complex transient absorption curves observed on flashing the flavin solution. The triplet decays by a first‐order process where k1= 1·1 × 10‐3. The chemiluminescence spectrum of skatole is identical with the fluorescence spectrum of o‐formamidoacetophenone in the same environment Similar results for 2,3‐dimethylindole lead to the identification of the acylamide anion as the emitter in indole chemiluminescence. A peroxide ring cleavage excitation mechanism is proposed. 104 sec‐1 and the semiquinone by a second‐order process where k2= 0·75 × 109 1.m‐1 sec‐1. The rate constants and extinction coefficients obtained enable decay curves to be calculated which fit satisfactorily those measured with the kinetic‐flash apparatus.
PHOTOBIOLOGY OF RNA BACTERIOPHAGES–II U.V.–IRRADIATION OF f2: EFFECTS ON EXTRACELLULAR STAGES OF INFECTION AND ON EARLY REPLICATION*
Authors: WERBIN HAROLD , VALENTINE RAYMOND C. , HILDALGO‐SALVATIERRA OSCAR , McLAREN A. D. 
Published: January 2008

Abstract— The effect of u.v. irradiation (2537 Å) on the RNA bacteriophage f2 has been studied with respect to the adsorption of f2 to E. coli K12 (male strain), the penetration of f2‐RN A into the host cell and the conversion of the phage nucleic acid to the double‐stranded replicative intermediate. The biological parameter most sensitive to u.v. was the plaque‐forming ability of the phage. Its loss could be attributed to several factors. (1). A binding of capsid protein to phage nucleic acid interfering with host penetration by the f2‐RNA. (2). Desorption of some irradiated phage at 37° from their attachment sites on the host. (3). Molecular alterations in the RNA preventing formation of the replicative intermediate within the host.The relationship of these factors to the lack of photoreactivability of irradiated f2 is discussed.
LETTUCE SEED GERMINATION: EFFECTS OF HIGH TEMPERATURE AND OF REPEATED FAR‐RED TREATMENT IN RELATION TO PHYTOCHROME
Authors: Scheibe Joseph , Lang Anton 
Published: January 2008

Abstract— At 37°C the active form of phytochrome in lettuce seed cannot function to promote subsequent germination. This effect of high temperature is distinct from thermal acceleration of dark reversion from the active form of phytochrome to the inactive form, and may be due to reversible denaturation of phytochrome.Repeated brief irradiations with far‐red light inhibit subsequent germination in the whole seed, whereas a similar irradiation regime results in a strong enhancement of the development of growth potential (ability to expand against an externally‐imposed osmotic restraint) in the excised axial portion of the seed. A possible explanation for these two opposing results, in volving two different pigment systems with effective loci in different parts of the seed, is suggested.
COMPARAISON ENTRE L'EMISSION D'OXYGENE ET L'EMISSION DE LUMINESCENCE A LA SUITE D'UNE SERIE D'ECLAIRS SATURANTS
Authors: BARBIERI GERARD , DELOSME RENE , JOLIOT PIERRE 
Published: January 2008

Abstract— Luminescence of Chlorella cells has been measured after illumination by a series of short saturating flashes.The intensity of luminescence is strongly dependent upon the number of flashes; luminescence is minimum after a single flash and maximum after a double flash illumination.Ifl/n is the intensity of luminescence measured 0.24 sec after the nth flash, the series ln shows oscillations as a function of n. The series ln is very similar to the series yn, in which y is the amount of oxygen evolved by the nth flash, the term ln corresponding to the term yn+1. To interpret the oscillations of the series yn, different models of system II photochemical centers have been proposed, one by ourselves and the other one by KOK et al. In these models the electron donor Z of photosystem 11 is supposed to have 2 or 4 levels of oxidation, the more oxidized state being the precursor of oxygen. These different oxidation states of the donor Z allow storage of the photic energy in the system. The correlation between the series yn and ln shows that at least one of the oxidized forms of the donor Z is a substrate for the luminescence reaction.
CHLOROPHYLL ONE‐ELECTRON PHOTOCHEMISTRY: LIGHT‐INDUCED ABSORBANCE CHANGES AND ESR SIGNALS FOR VARIOUS PORPHYRIN‐QUINONE AND HYDROQUINONE SYSTEMS IN ALCOHOL SOLVENTS*
Authors: WHITE ROBERT A. , TOLLIN GORDON 
Published: January 2008

Abstract— Light‐dark optical difference spectra of degassed ethanol or pyridine solutions of chlorophyll and benzoquinone or hydroquinone at temperatures above — 50°C show only the semiquinone absorbance band. Decay of the signals is second order, with a rate constant in agreement with earlier ESR results.Light‐induced optical changes due to chlorophyll can be elicited by lowering the temperature of ethanol solutions of chlorophyll and benzoquinone to a region of high viscosity. Hydroquinone is not effective in producing these optical changes.Similar results are achieved at room temperature by using as solvent a degassed mixture of the alcohols: cyclohexanol, tert‐butanol, and ethanol (CBE). Difference spectra show bleaching of the chlorophyll bands and increased absorbance in the intermediate wavelength region (460–580 nm). Decay kinetics are first order, while the rise is complicated (probably biphasic). ESR signals have no hyperfine structure and also decay by first order kinetics, at a rate which is faster than that of the optical changes. The ESR signals reach a steady state more rapidly than the optical signals, without biphasic kinetics. These results demonstrate that at least two species are generated.Addition of acid increases the amount of bleaching in CBE, while small amounts of base decrease it. Larger amounts of base cause chlorophyll bleaching to completely disappear and only the semiquinone anion is observed. Activation energies for the chlorophyll a‐benzoquinone photoreaction in CBE are 10–14 kcal/mole. Lower potential quinones give lower activation energies. The rate constant for quenching of the triplet state of chlorophyll a by β‐carotene in CBE is 7.5±0.5×108 (M set)‐1. β‐carotene also quenches photoproduct formation. The bimolecular rate constant for formation of the photoproduct with benzoquinone was calculated to be 7×108 (Msec)‐1.The redox potential of the quinone affects both the magnitude of the chlorophyll absorbance changes and the rate of decay. The higher the potential, the larger the changes and the slower the decay. Other porphyrin systems show similar photoreactions only if they are chelated with a group II metal, such as Mg2+, Cd+2, or Zn+2.The results are interpreted in terms of the formation, by a triplet‐sensitized one‐electron transfer from solvent to quinone, of a chlorophyll‐semiquinone complex which is stabilized via coordination with the chelated metal.
CHLOROPHYLL ONE‐ELECTRON PHOTOCHEMISTRY: FLASH PHOTOLYSIS STUDIES OF THE CHLOROPHYLL‐QUINONE REACTION IN ALCOHOL SOLVENTS*
Authors: WHITE ROBERT A. , TOLLIN GORDON 
Published: January 2008

Abstract— Flash photolysis of chlorophyll a alone in CBE (cyclohexanol‐t‐butanol‐ethanol) yields a difference spectrum similar to those obtained upon steady illumination of chlorophyll a‐quinone mixtures in this solvent. Decay kinetics in CBE and dimethylsulfoxide are faster at the Soret band than at 460–580 nm and red band regions. This difference is not obtained in other solvents (CHCI3, CCI4, t‐butanol, ethanol), implying that two or more species are obtained in CBE and DMSO.β‐Carotene in CBE increases the rate of decay of the flash‐induced chlorophyll transients at 430 and 660 nm but only decreases the magnitude of the signal at 470 nm. This implies that the 470 nm absorbance is due to a product formed from the triplet state. This effect is not observed in ethanol.Adding quinone to chlorophyll solutions results in slowly decaying species being generated by flash excitation in CBE. Three components can be distinguished: the first (t1/2˜ 0.2 msec) corresponds to the triplet state; the second (t1/2= 5–10 msec) is quinone concentration and species independent; the third (t1/2= several seconds) is dependent upon quinone concentration and species (rate is faster for higher concentrations and lower potential quinones). The ESR signal decay rate is approximately equal to the third component flash decay rate when the chlorophyll and quinone concentrations are equal. With excess quinone, the flash decay rate becomes faster, and the ESR decay rate decreases slightly. These slowly‐decaying species are not produced when quinone is added to chlorophyll a in ethanol or t‐butanol, or to pheophytin in CBE. One observes merely a decrease in signal height with no accompanying increase in decay rate.Mechanisms to account for all of these phenomena are presented which involve an initial chlorophyll triplet‐solvent reaction with the subsequent formation of several species of chloro‐phyll‐quinone radical complexes.
KINETIC STUDIES ON CHEMILUMINESCENCE OF CHLOROPLASTS INDUCED BY CHANGES IN ION CONCENTRATION
Authors: HARDT H. , MALKIN S. 
Published: January 2008

Abstract— Acid‐base, acid‐, and salt‐induced chemiluminescences of chloroplasts were investigated in relation to their dependences upon several time parameters:

The dependence of the three chemiluminescences on the preillumination time was similar; the luminescences rose to a maximum and then decayed to a steady‐state This behaviour depends on the preillumination level and the length of the dark time following the preillumination. Analysis of the above indicates the formation of quenching entities during the preillumination which react with the luminescence precursors mainly in the dark.In contrast, the delayed light measured after 22 msec from the preillumination, showed a much slower but smooth rise to the steady‐state with no subsequent drop.
During the dark period following preillumination the ability of the system to chemi‐luminescence decayed with a first order rate.
During emission the above chemiluminescences decayed with a first order law. The total emission in different experiments was also proportional to the maximum emission, in agreement with a first order law of decay.
The comparison of the kinetic behaviour of the three types of chemiluminescence indicates common precursors of luminescence for at least the acid‐base and the salt types. The delayed emission at 22 msec however, seems to have separate precursors than the three chemiluminescences.
CHANGES IN U.V. SURVIVAL CURVES OF ESCHERICHIA COLl B/r CONCOMITANT WITH CHANGES IN GROWTH CONDITIONS
Authors: RUDÉ J. , ALPER TIKVAH 
Published: January 2008

Abstract— For E. coli B/r u.v.‐irradiated while in logarithmic growth, the nature of the dose‐response curve was strongly dependent on both pre‐ and post‐irradiation conditions of growth. Survival curves for cells grown in nutrient medium, or minimal medium with glucose, and plated immediately after irradiation, demonstrated an initial insensitive or ‘shoulder’ region provided the plating medium was such that no derepression was required of operons controlling inducible enzyme systems. If, however, such derepression was called for, survival curves were of exponential form. Delay in plating resulted in the return of the survival curve to the shouldered form even when ‘shift‐down’ media were used.Of those cells grown before u.v.‐irradiation in minimal media and plated thereafter with the same sugar as carbon source, only those grown with glucose (or lactose) demonstrated the shouldered survival curve.
FORMES TRANSITOIRES DES CAROTENOIDES: ETAT TRIPLET ET RADICAL‐CATION
Authors: MATHIS P. , VERMEGLIO A. 
Published: January 2008

Abstract— Reactions between toluidine blue (a thiazine dye) and carotenoids (β‐carotene and zeaxanthine) were studied by flash photolysis, in ethanolic solutions. Two types of reactions were evidenced:

a triplet‐triplet energy transfer from the triplet state of monoprotonated toluidine blue to the carotenoid whose triplet state decays rapidly (t1/2= 5μsec).
an electron transfer from the carotenoid to the mono‐ and bi‐protonated triplet states of toluidine blue. This produces a radical‐cation of the carotenoid (Car+) which decays slowly (t1/2˜ 200 μsec) and has a strong absorption band around 900 nm.