Thermal transitions in mixtures of polydeoxyribodinucleotides

Oligo d(C-A) and oligo d(T-G) of known average lengths, prepared by a combination of chemical and enzymatic procedures, have been mixed in 0.02 M and 0.07 M Na⁺, and absorbance has been studied as a function of increasing temperature. The transitions have been analyzed for the temperature of maximum slope T_m, the breadth of the transition, the value of the slope at T_m, and the maximum hyperchromicity. Linear expressions have been found relating the inverse of the length in nucleotide units (n^?1) of the shorter oligomer, irrespective of its identity, to T_m and also to the transition breadth. From a difference in slope between the T_m versus n^?1 expressions for the two molarities, the entropy and enthalpy of melting have been calculated as a function of n^?1.     

Quantitative analysis of the redox states of cytochromes in a living L929 (NCTC) cell by resonance Raman microspectroscopy

Raman spectra and images of a living L929 (NCTC) cell have been measured with 532 nm excitation. Both reduced and oxidized forms of cytochromes b and c (cyt b and cyt c) have been observed in situ without any pretreatment. The redox states of cyts b and c have been assessed quantitatively with a spectral analysis. It has been found that reduced cyt c is more abundant than oxidized cyt c, while oxidized cyt b is slightly more abundant than reduced cyt b in a living cell. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

编码内质网膜蛋白的新基因家族RTN的研究进展

蛋白质的分泌渠道是近几年生命科学研究焦点之一.RTN（reticulon）是定位于内质网膜上的一个基因家族,现已发现RTN1、RTN2、RTN3、RTN4等多个家族成员.其中,这些基因在蛋白质分泌加工过程中的具体作用,以及RTN1（即NSP）作为神经内分泌特异性的标志或与神经元分化的关系都在进一步探讨之中.     

Review of dermatophytoses in Galicia from 1951 to 1987, and comparison with other areas of Spain

We have reviewed all the dermatophytoses diagnosed in Galicia during four consecutive 9-year periods 1951–86 and 1987. From 4571 patients, we isolated 3351 fungal strains belonging, in decreasing order of frequency, to the following dermatophyte species: Microsporum canis (25.5%), Trichophyton rubrum (24.6%), T. mentagrophytes (21.4%), Epidermophyton floccosum (11.8%), M. gypseum (5.2%), T. tonsurans (3.9%), T. verrucosum (3.1%), T. schoenleinii (2.5%), T. violaceum (1.2%), T. mengninii (0.3%), M. audouinii (0.2%), T. equinum (0.1%) and T. soudanense (0.1%). Tinea capitis has diminished in frequency since 1951, though there was been a slight increase since 1978; M. canis has always been the most common agent, and between 1951 and 1959 T. schoenleinii was also very frequent but is no longer found. The frequency of tinea corporis, on the other hand, has experienced a considerable increase. Its most common causal agents in the last few years have been T. mentagrophytes, M. canis and T. rubrum. Until 1977 the most common tinea cruris dermatophyte was E. floccosum, but since then it has been T. rubrum. The commonest tinea pedis dermatophytes have been T. rubrum and T. mentagrophytes. Tinea unguium and tinea barbae have been the most frequent dermatophytoses, and their commonest causal agents T. rubrum and T. mentagrophytes respectively. We have documented the distribution of the various causal agents by location of the lesions, age and source of the patients (private or National Health Service patients), and we have compared the results with those obtained in other regions of Spain.     

Phylogenetic relationships of the Atoposauridae (archosauria,crocodylomorpha)

A systematic revision of the family Atoposauridae is presented, interpreting and reviewing their relationships. The seventy‐one characters have been divided into cranial, postcranial and metric which have been used in three separate cladistic analyses in order to discuss their concordance. Polarities, in each case, have been deduced from distinct outgroups. We have used a PHYLIP program (version 2.9). There are five valid taxa of Atoposauridae: Alligatorellus beaumonti (rejecting the two subspecific taxa) Alligatorium meyeri, Theriosuchus pusillus. Alligatorium depereti (which is transferred to a new genus Montsecosuchus) and Aloposaurus (discussed as a nomen dubium). The three cladograms are not fully concordant. The relative level of derivation in postcranial and cranial characters suggests congruence. The metric traits seem to retain, in general, a primitive condition. The final proposed cladogram clusters Alligatorium + Alligatorellus as the sister group of Montsecosuchus + Theriosuchus.     

Ecology of Testate Amoebae from Oligotrophic Peatlands: Specific Features of Polytypic and Polymorphic Species

Relationships between species abundance and water table depth and soil moisture have been modeled using weighted averaging and species niches have been calculated as optima and tolerance for these parameters. Niche separation of closely related taxa has been examined in detail and it has been shown that there is often a gradient of hydrological preference within each taxon. Wet to dry gradients include those found in the Trigonopyxis arcula group (T. arcula var. major > T. arcula > T. minuta), Assulina–Valkanovia group (A. seminulum > A. muscorum > V. elegans), and Trinema lineare group (T. lineare var. truncatum > T. lineare > T. lineare var. terricola), all of which are associated with a large to small size gradient. In addition, spined forms within the Euglypha and Placocista genera have been shown to consistently occur in wetter habitats than glabrous forms of those with shorter spines. A conclusion has been drawn that palaeoecological studies should cover the lowest taxa possible within these groups to maximize the ecological indicator value of the assemblages recorded.     

Expression and function of the bHLH genes ALCATRAZ and SPATULA in selected Solanaceae species

The genetic mechanisms underlying fruit development have been identified in Arabidopsis and have been comparatively studied in tomato as a representative of fleshy fruits. However, comparative expression and functional analyses on the bHLH genes downstream the genetic network, ALCATRAZ (ALC) and SPATULA (SPT), which are involved in the formation of the dehiscence zone in Arabidopsis, have not been functionally studied in the Solanaceae. Here, we perform detailed expression and functional studies of ALC/SPT homologs in Nicotiana obtusifolia with capsules, and in Capsicum annuum and Solanum lycopersicum with berries. In Solanaceae, ALC and SPT genes are expressed in leaves, and all floral organs, especially in petal margins, stamens and carpels; however, their expression changes during fruit maturation according to the fruit type. Functional analyses show that downregulation of ALC/SPT genes does not have an effect on gynoecium patterning; however, they have acquired opposite roles in petal expansion and have been co‐opted in leaf pigmentation in Solanaceae. In addition, ALC/SPT genes repress lignification in time and space during fruit development in Solanaceae. Altogether, some roles of ALC and SPT genes are different between Brassicaceae and Solanaceae; while the paralogs have undergone some subfunctionalization in the former they are mostly redundant in the latter.     

Analysis of insect toxin complex gene variability of <Emphasis Type="Italic">Yersinia pestis</Emphasis> and <Emphasis Type="Italic">Yersinia pseudotuberculosis</Emphasis> strains

The nucleotide sequences of the Tc’s insect toxin complex genes have been analyzed in 18 natural strains of the main and non-main subspecies of Yersinia pestis isolated in different natural foci in the Russian Federation, as well as neighboring and more remote countries, as compared to the data on Y. pestis and Y. pseudotuberculosis strains stored in the NCBI GenBank database. The nucleotide sequences of these genes in plague agent strains have been found to be highly conserved, in contrast to those of the pseudotuberculosis agent. The sequences of two genes, tcaC and tccC2, have been found to be almost identical in Y. pestis strains, whereas other three genes (tcaA, tcaB, and tccC1) contain a few mutations, which, however, are not common for all strains of the plague agent. Exceptions are only strains of the Y. pestis biovar orientalis, whose tcaB gene is in a nonfunctional state due to a nucleotide deletion. The results suggest that the formation of the species Y. pestis as an agent of a natural focal infection with a transmissive mechanism has not resulted in degradation of the Tc’s complex genes. Instead, these genes are likely to have been altered as the plague agent have been adapting to the new environment.     

Herbicidal inhibitors of amino acid biosynthesis and herbicide-tolerant crops

Summary. Acetohydroxyacid synthase (AHAS) inhibitors interfere with branched-chain amino acid biosynthesis by inhibiting AHAS. Glyphosate affects aromatic amino acid biosynthesis by inhibiting 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Glufosinate inhibits glutamine synthetase and blocks biosynthesis of glutamine. AHAS gene variants that confer tolerance to AHAS inhibitors have been discovered in plants through selection or mutagenesis. Imidazolinone-tolerant crops have been commercialized based on these AHAS gene variants. A modified maize EPSPS gene and CP4-EPSPS gene from Agrobacterium sp. have been used to transform plants for target-based tolerance to glyphosate. A gox gene isolated from Ochrobactrum anthropi has also been employed to encode glyphosate oxidoreductase to detoxify glyphosate in plants. Glyphosate-tolerant crops with EPSPS transgene alone or both EPSPS and gox transgenes have been commercialized. Similarly, bar and pat genes isolated from Streptomyces hygroscopicus and S. viridochromogenes, respectively, have been inserted into plants to encode phosphinothricin N-acetyltransferase to detoxify glufosinate. Glufosinate-tolerant crops have been commercialized using one of these two transgenes.     

Genetics,Genomics and Breeding of Late Blight and Early Blight Resistance in Tomato

Late blight (LB), caused by the oomycete Phytophthora infestans, and early blight (EB), caused by the fungi Alternaria solani and A. tomatophila, are two common and destructive foliar diseases of the cultivated tomato (Solanum lycopersicum) and potato (Solanum tuberosum) in the United States and elsewhere in the world. While LB can infect and devastate tomato plants at any developmental stages, EB infection is usually associated with plant physiological maturity and fruit load where older senescing plants exhibit greater susceptibility and a heavy fruit set enhances the disease. At present, cultural practices and heavy use of fungicides are the most common measures for controlling LB and EB. Genetic resources for resistance have been identified for both diseases, largely within the tomato wild species, in particular the red-fruited species S. pimpinellifolium and the green-fruited species S. habrochaites. A few race-specific major resistance genes (e.g., Ph-1, Ph-2 and Ph-3) and several race-nonspecific resistance QTLs have been reported for LB. Ph-3 is a strong resistance gene and has been incorporated into many breeding lines of fresh market and processing tomato. However, new P. infestans isolates have been identified which overcome Ph-3 resistance. Recently, a new resistance gene (Ph-5) has been identified, which confers resistance to several pathogen isolates including those overcoming the previous resistance genes. Advanced breeding lines including Ph-5 alone and in combinations with Ph-2 and Ph-3 are being developed. Genetic controls of EB resistance have been studied and advanced breeding lines and cultivars with improved resistance have been developed through traditional breeding. Additionally, QTLs for EB resistance have been identified, which can be utilized for marker-assisted resistance breeding. Currently, new inbred lines and cultivars of tomato with good levels of EB resistance and competitive yield performance are being developed at the Pennsylvania State University. This review will focus on the current knowledge of both LB and EB with respect to the causal pathogens, host resistances, and genetics and breeding progresses.     

On the Pollen Morphology of Some scandinavian caryophyllaceae

A total of 36 species, varieties and hybrids from nine genera of Scandinavian Caryophyllaceae with pantoporate pollen grains have been investigated. Habrosia spinuliflora, a non-Scandinavian plant with pantoporate pollen grains, has also been investigated. Diagnoses (p. 71–80) and photomicrographs (including some photopalynograms) are provided. Measurements, etc., are given in tabular form (Tab. 1, p. 68). The smallest grains were found in Gypsophila muralis (24 μ) and Habrosia spinuliflora (27 μ), the largest in Agrostemma githago (63 μ) and Stellaria palustris (60 μ). The number of apertures ranges from 31–37(–45) in Agrostemma githago, Lychnis flos-cuculi and Melandrium album to 12 in Scleranthus perennis, Gypsophila fastigiata, Dianthus deltoides and several species of Stellaria etc.

Thin sections of pollen grains in four species have been described (p. 81). Two main types of arrangement of bacula have been encountered. One type has through bacula, connecting nexine and tegillum (e.g. in Silene, Lychnis, Viscaria, etc.). In the other type the bacula are of two different lengths: some connect nexine and tegillum, others are shorter, hanging from the tegillum half-way towards the nexine (e.g. in Stellaria and Dianthus). The nexine seems to consist of a homogeneous, undifferentiated layer. Electron micrographs of pollen grains in seven species have been made (Pl. 17–20).

In Melandrium intergrading pattern types have been observed. M. viscosum has a pattern similar to that in Silene (M. viscosum should, therefore, no doubt be referred to as Silene viscosa). M. album has tetrate grains with large spinules. M. angustiflorum shows a pattern transitional between tetrate-punctitegillate and intectate-reticulate. M. noctiflorum, M. rubrum and M. apetalum have reticulate pollen grains. The hybrid M. album × rubrum has characters from both parental stocks. The pollen grains in Stellaria holostea (Pl. 13: 9–13) deviate from those in the other Stellaria species, whereas Stellaria aquatica (formerly Malachium aquaticum) shows a close morphological similarity with the other species of Stellaria (except S. holostea) It should, therefore, probably better be retained in Stellaria. A key for identification is found on p. 86.     

Characterization of the first dominant dwarf maize mutant carrying a single amino acid insertion in the VHYNP domain of the <Emphasis Type="Italic">dwarf8</Emphasis> gene

The “green revolution” involving mainly wheat and rice was based on the use by breeders of semidominant mutations involved in the signal transduction pathway of Gibberellin (GA). In particular, mutations in the Reduced height (Rht) gene of wheat have been used to reduce plant height and consequently to avoid storm damage and lodging. These genes have been cloned and they encode for DELLA proteins which contain an N-terminal DELLA and a VHYNP domain essential for GA-dependent degradation of these proteins. In maize several mutations have been isolated which affect gibberellin biosynthesis and perception and in particular, mutations in Dwarf8 (D8) gene cause a severe dwarfing phenotype. D8 gene has been identified as an orthologue of Rht (Reduced height), Slr1(Slender rice 1) and Gibberellic Acid Insensitive (GAI) genes, this latter is a negative regulator of GA response in Arabidopsis. In this work, for the first time, we isolated and characterized a single amino acid insertion in the VHYNP domain of D8 maize gene causing the appearance of a dominant dwarf mutation. This spontaneous mutation, named D8-1023, showed a phenotype which is less severe in comparison with the other D8 mutants previously isolated which have modifications in the DELLA domain. This mutant appears to be an useful tool either to study the mechanism of GA-modulated growth in plants or to lower the height of maize tropical germplasm for breeding purposes.     

Thiamin biosynthesis in prokaryotes

Twelve genes involved in thiamin biosynthesis in prokaryotes have been identified and overexpressed. Of these, six are required for the thiazole biosynthesis (thiFSGH, thiI, and dxs), one is involved in the pyrimidine biosynthesis (thiC), one is required for the linking of the thiazole and the pyrimidine (thiE), and four are kinase genes (thiD, thiM, thiL, and pdxK). The specific reactions catalyzed by ThiEF, Dxs, ThiDM, ThiL, and PdxK have been reconstituted in vitro and ThiS thiocarboxylate has been identified as the sulfur source. The X-ray structures of thiamin phosphate synthase and 5-hydroxyethyl-4-methylthiazole kinase have been completed. The genes coding for the thiamin transport system (thiBPQ) have also been identified. Remaining problems include the cloning and characterization of thiK (thiamin kinase) and the gene(s) involved in the regulation of thiamin biosynthesis. The specific reactions catalyzed by ThiC (pyrimidine formation), and ThiGH and ThiI (thiazole formation) have not yet been identified. Received: 23 August 1998 / Accepted: 16 January 1999     

Synthesis of thiazol-2-imines from the reduction of single enantiomer 2-imino-thiazolidin-4-ones followed by a spontaneous water elimination

Chiral hemiaminals ( 5-8RR and 5-8SS ) have been synthesized from the corresponding 2-iminothiazolidine-4-ones ( 1-4RR and 1-4SS ) by LiAlH₄ reductions stereoselectively and were then converted to single enantiomer thiazol-2-imines ( 9-12RR and 9-12SS ) by a water elimination reaction. The kinetics of the dehydration reactions which occurred spontaneously both in the solid state and in the solution have been followed by time dependent ¹H nuclear magnetic resonance spectroscopy. The corresponding first order rate constants and free energies of activation values for the conversions have been reported.     

Prédateurs et parasites d'Aphytis [Hym., Aphelinidae]

Summary Very few predators and parasites ofAphytis have been recorded. Among predators, only Coccinellids preying on Diaspine scale insects have been mentioned as damaging to the preimaginal stages ofAphytis on occasion, and a single case of a mitePyemotidae has been known to have destroyed the pupae. As to the parasites known, they are accidental and rare. There are cases where only the male lives as a parasite onAphytis, the female developing normally as a primary parasite onAphytis hosts. Two species harmful toAphytis have been found in Lebanon:Pyemotes herfsi Oudemans (Acarina, Pyemotidae) andApterencyrtus adeli n. sp. (Hymenoptera, Encyrtidae). P. herfsi is a polyphagous predator, and its increase in number might constitute a threat to theAphytis in the field and the insectary.A. adeli is the only example known so far of a true hyperparasite whose males and females develop onAphytis. It has been found abundantly on larvae ofAphytis mytilaspidis as well as on many other hosts.

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Extrait d'une thèse de Doctorat de troisième cycle (biologie animale) soutenue à la Faculté des Sciences de l'Université de Paris le 2 avril 1968.     

S-adenosyl methionine requiring mutants in Saccharomyces cerevisiae: evidences for the existence of two methionine adenosyl transferases.

Summary Mutants requiring S-adenosyl methionine (SAM) for growth have been selected in Saccharomyces cerevisiae. Two classes of mutants have been found. One class corresponds to the simultaneous occurrence of mutations at two unlinked loci SAM1 and SAM2 and presents a strict SAM requirement for growth on any medium. The second class corresponds to special single mutations in the gene SAM2 which lead to a residual growth on minimal medium but to normal growth on SAM supplemented medium or on a complex medium like YPGA not containing any SAM. These genetic data can be taken as an indication that Saccharomyces cerevisiae possesses two isoenzymatic methionine adenosyl transferases (MAT). In addition, SAM1 and SAM2 loci have been identified respectively with the ETH-10 and ETH2 loci previously described.Biochemical evidences corroborate the genetic results. Two MAT activities can be dissociated in a wild type extract (MATI and MATII) by DEAE cellulose chromatography. Mutations at the SAM1 locus lead to the absence or to the modification of MATII whereas mutations at the SAM2 locus lead to the absence or to the modification of MATI. Moreover, some of our results seem to show that MATI and MATII are associated in vivo.     

Overproduction of the protein encoded by the maize transposable element Ac in insect cells by a baculovirus vector

Summary The polypeptide encoded in the Activator (Ac) element of Zea mays L. has been expressed in Spodoptera frugiperda insect cells using plasmids which carry the strong polyhedrin promoter of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV). Recombinant AcNPVs with the Ac-cDNA integrated and under the control of the viral polyhedrin promoter have been isolated and their genomes have been partly characterized as to the location of the foreign DNA insert. Upon infection of S. frugiperda cells with the recombinant AcNPV, maize Ac element specific messenger RNAs, as well as a newly synthesized polypeptide with an apparent molecular weight of about 116 kDa, have been detected in extracts of recombinant infected cells. This polypeptide is absent from extracts of wild-type infected cells expressing the polyhedrin polypeptide which can be recognized by the presence of nuclear inclusion bodies. Recombinant infected cells lack this protein. The Ac specific polypeptide is detected by antisera, which have been raised against fusion proteins containing Ac sequences synthesized in Escherichia coli, both in immunoprecipitation and in Western blotting experiments. The Ac specific protein is a nuclear phosphoprotein and represents about 1%–2% of the newly synthesized protein.     

Molecular Evolution of the mtDNA Encoded <Emphasis Type="Italic">rps3</Emphasis> Gene Among Filamentous Ascomycetes Fungi with an Emphasis on the Ophiostomatoid Fungi

The mitochondrial ribosomal protein S3 (rps3) gene within the fungi is extremely diverse in location and organization, some versions of this gene have been incorporated into a group I intron, others appear to have gained large insertions, microsatellite expansions, or have been invaded by homing endonucleases. Among the ascomycetes fungi the group I intron encoded version of rps3 appears to have a rather complex evolutionary history including first the acquisition of rps3 by a group I intron (mL2449), the loss of the mL2499 intron and the establishment of rps3 as a free-standing gene, and the eventual loss of the intron derived version of rps3.