The mutants compacta ?hnlich, Nitida and Grandiflora define developmental compartments and a compensation mechanism in floral development in Antirrhinum majus

In order to improve our understanding of floral size control we characterised three mutants of Antirrhinum majus with different macroscopic floral phenotypes. The recessive mutant compacta ?hnlich has smaller flowers affected mainly in petal lobe expansion, the dominant mutant Grandiflora has overall larger organs, whilst the semidominant mutation Nitida exhibits smaller flowers in a dose-dependent manner. We developed a cell map in order to establish the cellular phenotypes of the mutants. Changes in organ size were both organ- and region-specific. Nitida and compacta ?hnlich affected cell expansion in proximal and distal petal regions, respectively, suggesting differential regulation between petal lobe regions. Although petal size was smaller in compacta ?hnlich than in wild type, conical cells were significantly bigger, suggesting a compensation mechanism involved in petal development. Grandiflora had larger cells in petals and increased cell division in stamens and styles, suggesting a relationship between genes controlling organ size and organ identity. The level of ploidy in petals of Grandiflora and coan was found to be equivalent to wild type petals and leaves, ruling out an excess of growth via endoreduplication. We discuss our results in terms of current models about control of lateral organ size.     

Tagesaktivit?t, Nestbaumethode und Brutverhalten des HonigsaugersNectarinia (Aidemonia)kilimensis in Zentralafrika

Zusammenfassung Ein Paar des HonigsaugersNectarinia kilimensis wurde in der Brutzeit beim Nestbau 21 Stunden beobachtet. Über die Bauaktivität gibt Abb. 2 Aufschluß. 140 von 144 Anflügen mit Nistmaterial waren auf 8 Stunden von 8^h–16^h konzentriert. Das Nistmaterial bestand fast ausschließlich aus Halmen, Pflanzenwolle und Spinnweben; dieses Material wurde von Anfang an abwechselnd verwendet. Nur das hat gebaut. Die Baumethoden werden beschrieben, ebenso verschiedene Balzhandlungen des . Der Nestbau dauerte 4 1/2, beim folgenden Nest 3 1/2 Tage.Beim Brüten waren Schnabel und Oberkopf des sichtbar. Während der Bauzeit wurde ein ausgeflogenes juv. nur vom gefüttert. Als es mindestens 17 Tage alt war, wurde es vom , 6 Tage später auch vom aggressive gejagt, doch war dieses juv. mehr als 3 Wochen nach dem Ausfliegen noch im Revier.

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Day-time activity, nest-building method and breeding behaviour of Bronze SunbirdNectarinia (Aidemonia) kilimensis in Central Africa

Summary A pair of Bronze SunbirdsNectarinia kilimensis was observed nest building over a period of 21 hours in the breeding season. Fig. 2 gives information on building activity. Of 144 arrivals with nest material 140 were concentrated in 8 hours from 08.00 to 16.00 hrs. Nest material consisted almost exclusively of grasses, plants, down and spider's webs; this material was, from the outset, used in an alternating pattern. The alone did the building. Nest-building methods are described, also various courtship activities of the . Nest building took 4 1/2 days, in the case of a second nest, 3 1/2 days.The 's bill and crown were visible when she was incubating. One young that had left the nest was fed by the alone. At least 17 days after this young one had fledged, it was chased aggressively by the , 6 days later also by the ; despite this, the same young bird was still in the territory more than three weeks after it had fledged.

     

What is a bona fide mating-type gene? Internuclear complementation of mat mutants in Podospora anserina

In the heterothallic ascomycete Podospora anserina, the mating-type locus is occupied by two mutually exclusive sequences termed mat+ and mat–. The mat+ sequence contains only one gene, FPR1, while the mat– sequence contains three genes: FMR1, SMR1 and SMR2. Previous studies have demonstrated that FPR1 and FMR1 are required for fertilization. Further analyses have led to the hypothesis that mat+ and mat– genes establish a mat+ and mat– nuclear identity, allowing recognition between nuclei of opposite mating type within the syncytial cells formed after fertilization. This hypothesis was based on the phenotypes of strains bearing mutations in ectopic mat genes. Here we present an analysis of mutations in resident mat– genes which suggests that, unlike FMR1 and SMR2, SMR1 is not involved in establishing nuclear identity. In fact, mutations in these two genes impair nuclear recognition, leading to uniparental progeny, while mutations in SMR1 block the sexual process, probably at a step after nuclear recognition. The nuclear identity hypothesis has also been tested through internuclear complementation tests. In these experiments, the mat– mutants were crossed with a mat+ strain carrying the wild-type mat– genes. Our rationale was that internuclear complementation should not be possible for nuclear identity genes: the relevant genes should show nucleus-restricted expression, and diffusion of their products to other nuclei should not occur. This test confirmed that SMR1 is not a bona fide mat gene since it can fulfill its function whatever its location, in either a mat− or a mat+ nucleus, and even when present in both nuclei. SMR2, but not FMR1, behaves like a nuclear identity gene with respect to internuclear complementation tests. A model is proposed that tentatively explains the ambiguous behaviour of the FMR1 gene and clarifies the respective functions of the three mat– proteins. Received: 15 October 1996 / Accepted: 25 April 1997     

Functional characterization of kanB by complementing in engineered Streptomycesfradiae ?neo6::tsr

A putative aminotransferase gene, kanB, lies in the biosynthetic gene cluster of Streptomyces kanamyceticus ATCC 12853 and has 66% identity with neo6 in neomycin biosynthesis. Streptomyces fradiae ∆neo6::tsr was generated by disrupting neo6 in the neomycin producer Streptomyces fradiae. Neomycin production was completely abolished in the disruptant mutant but was restored through self-complementation of neo6. S. fradiae HN4 was generated through complementation with kanB in Streptomyces fradiae ∆neo6::tsr. Based on metabolite analysis by ESI/MS and LC/MS, neomycin production was restored in Streptomyces fradiae HN4. Thus, like neo6, kanB also functions as a 2-deoxy-scyllo-inosose aminotransferase that has dual functions in the formation of 2-deoxy-scyllo-inosose (DOS). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Singlet oxygen formation and chlorophyll a triplet excited state deactivation in the cytochrome b6f complex from Bryopsis?corticulans

We have attempted to investigate the correlation between the detergent-perturbed structural integrity of the Cyt b ₆ f complex from the marine green alga Bryopsis corticulans and its photo-protective properties, for which the nonionic detergents n-octyl-β-d-glucopyranoside (β-OG) and n-dodecyl-β-d-maltoside (β-DM), respectively, were used for the preparation of Cyt b ₆ f, and the singlet oxygen (¹O₂*) production as well as the triplet excited-state chlorophyll a (³Chl a*) formation and deactivation were examined by spectroscopic means. Near-infrared luminescence of ¹O₂ * (~1,270 nm) on photo-irradiation was detected for the β-OG preparation where the complex is mainly in oligomeric state, but not for the β-DM one in which the complex exists in dimeric form. Under anaerobic condition, photo-excitation of Chl a in the β-DM preparation generated ³Chl a* with a lower quantum yield of Φ_T ~ 0.02 and a longer lifetime of ~600 μs with respect to those as in the case of β-OG preparation, Φ_T ~ 0.12 and 200–300 μs. These results prove that the enzymatically active and intact Cyt b ₆ f complex on photo-excitation tends to produce little ³Chl a* or ¹O₂ *, which implies that the pigment–protein assembly of Cyt b ₆ f complex per se is crucial for photo-protection. F. Ma and X.-B. Chen contributed equally to this work.     

ΓОРИЗОНТ С Polydesmia И ИХ РОДСТВЕННЫЕ СВЯЗИ С Ordosoceras

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Transformation of androgenic-derived Festulolium plants (Lolium?perenne L.?×?Festuca?pratensis Huds.) by Agrobacterium?tumefaciens

Genetic transformation of androgenic-derived amphidiploid Festulolium plants (Lolium perenne L. × Festuca pratensis Huds., 2n = 4x = 28) by Agrobacterium tumefaciens has been achieved. Anther culture-induced calli of Festulolium “Bx351” were inoculated with Agrobacterium tumefaciens strain LBA4404 carrying pIG121-Hm encoding the hygromycin resistance (hph) and β-glucuronidase (uidA) genes under the control of a CaMV 35S promoter. Twenty-three putative transformants were obtained from the hygromycin selection, 19 of which (82.6%) showed GUS activity. The integration of transgene was detected by using genomic DNA PCR analysis, RT-PCR analysis and Southern blot hybridization, respectively, which revealed that foreign gene was integrated into the genomes of dihaploid transformants (2n = 2x = 14). The haploid embryogenic system offers a stable means of transformation, as the introduced trait can be readily fixed through chromosome doubling. An erratum to this article can be found at     

Trichoderma harzianum strain T-22 induces changes in phytohormone levels in cherry rootstocks (Prunus cerasus?×?P. canescens)

The aim of this research was to explain the direct plant growth-promoting activity of Trichoderma harzianum strain T-22 (T22), hypothesizing the involvement of different classes of plant growth regulators. Seven days after the transfer to root-inducing medium, in vitro-cultured shoots of GiSeLa6^? (Prunus cerasus  × P. canescens) were inoculated with T22. Root and shoot growth were significantly affected by T22 (+76 and +61%, respectively). Ten days after inoculation, the levels of indole-3-acetic acid (IAA), trans-zeatin riboside (t-ZR), dihydrozeatin riboside (DHZR), gibberellic acid (GA3) and abscisic acid (ABA) were analyzed by high performance liquid chromatography coupled with mass spectrometry. The results showed that after T22-inoculation, IAA and GA3 significantly increased in both leaves (+49 and +71%, respectively) and roots (+40 and +143%, respectively) whereas t-ZR decreased (−51% in leaves and −37% in roots). Changes in DHZR were observed in T22-inoculated roots (−32%) but not in leaves, whereas the levels of ABA did not differ between the two treatments. The extraction method allowed the simultaneous extraction of phytohormones. There is evidence that the change in phytohormone levels is one of the direct mechanism by which T22 promotes rooting and shoot growth, with notable advantages for rootstock production during nursery processes.     

Picus leuconotus in B?hmen erlegt

Ohne Zusammenfassung     

Induction of a Streptomyces cacaoi β-lactamase gene cloned in S. lividans

Summary The previously cloned class A -lactamase gene (bla) of Streptomyces cacaoi was shown to be inducible by -lactam compounds in the host organism S. lividans. A regulatory region of 2.75 kb was identified and the nucleotide sequence determined. It contained four open reading frames (ORFs) of which only two were complete and required for induction. ORF1-ORF2 exerted a positive regulatory effect on the expression of bla. Inactivation of ORF1 or of ORF2 resulted not only in the loss of induction, but also in a 30- to 60-fold decrease in the basal (non-induced) level of -lactamase production. ORF1 codes for a DNA-binding protein related to the AmpR repressor/activator, which controls the expression of ampC (class C -lactamase) genes in several Enterobacteria.     

Der Bienenfresser(Merops apiaster L.) in ?sterreich

Ohne Zusammenfassung     

Dynamic organization of the β-heterochromatin in the Drosophila melanogaster polytene X chromosome

Region 20 of the polytene X chromosome of Drosophila melanogaster was studied in salivary glands (SG) and pseudonurse cells (PNC) of otu mutants. In SG chromosomes the morphology of the region strongly depends on two modifiers of position effect variegation: temperature and amount of heterochromatin. It is banded in XYY males at 25° C and β-heterochromatic in X0 males at 14° C, i.e. it shows dynamic transitions. In PNC chromosomes region 20 is not heterochromatic, but demonstrates a clear banding pattern. Some molecular markers of mitotic heterochromatin were localized by means of in situ hybridization on PNC chromosomes: DNA of the gene su(f) in section 20C, the nucleolar organizer and 359-bp satellite in 20F. The 359-bp satellite, which has been considered to be specific for heterochromatin of the mitotic X chromosome, was found at two additional sites on chromosome 3L, proximally to 80C. The right arm of the X chromosome in SG chromosomes was localized in the inversion In(1LR)pn2b: the telomeric HeT-A DNA and AAGAG satellite from the right arm are polytenized, having been relocated from heterochromatin to euchromatin. Received: 1 July 1998 / Accepted: 7 September 1998     

A ThCAP gene from Tamarix hispida confers cold tolerance in transgenic Populus (P. davidiana?×?P. bolleana)

The ThCAP gene, which encodes a cold acclimation protein, was isolated from a Tamarix hispida NaCl-stress root cDNA library; its expression patterns were then assayed by qRT-PCR in different T. hispida tissues treated with low temperature (4°C), salt (400 mM NaCl), drought (20% PEG6000) and exogenous abscisic acid (100 μM). Induction of ThCAP gene was not only responsive to different stress conditions but was also organ specific. When transgenic Populus (P. davidiana × P. bolleana) plants were generated, expressing ThCAP under regulation of the cauliflower mosaic virus CaMV 35S promoter, they had a greater resistance to low temperature than non-transgenic seedlings, suggesting that ThCAP might play an important role in cold tolerance.     

Aims

In wetlands, water levels can fluctuate, which often disturbs local organisms, such as aquatic plants. The responses of Alternanthera philoxeroides, Myriophyllum aquaticum, and Ludwigia adscendens to water level fluctuations of different frequencies were examined here.     

Aims

Forest microclimate is the local environment generated through the interaction between regional climate and forest structure. Studies on forest microclimate not only have theoretical significances in ecology but also practical meanings in forest management practices and wood production. Radiation budget and energy balance is the basis for microclimate. Few studies have performed the radiatoin budget and energy balance analysis at regional scale. Here, we focused at this for the East Asia.     

DnaK-dependent ribosome biogenesis in Escherichia coli? : competition for dominance between the alleles dnaK756 and dnaK ?+

The Escherichia coli chaperone DnaK is vital for many cellular functions, including ribosome biogenesis at high temperature. Thus, the dnaK756-ts (λ ^R ) mutant, at the non-permissive temperature, is inhibited at a late stage of ribosome assembly, yielding 21S, 32S and 45S precursor particles. This defect, unlike the λ resistance and thermosensitivity phenotypes, is not complemented by lysogenisation with a transducing phage λ dnaK ⁺ bearing the wild-type dnaK gene. However this dominant phenotype becomes recessive when dnaK ⁺ is expressed from a medium-copy-number plasmid. On the other hand, an excess of DnaK causes an unexpected dominant-lethal effect of the dnaK756 allele near non-permissive temperatures. This interplay between the dnaK ⁺ and dnaK756 alleles supports the idea of that DnaK oligomers form in the cell. Received: 28 April 1998 / Accepted: 24 July 1998     

über die H?henanpassung vonCrotophaga ani undTyrannus melancholicus in den Anden Kolumbiens

Zusammenfassung An Trauertyrann,Tyrannus melancholicus Vieillot, 1819 (Tyrannidae) und Ani,Crotophaga ani L., 1758 (Cuculidae) wird geprüft, wie weit in verschiedenen Höhenlagen der Anden Kolumbiens Veränderungen einzelner Körpermerkmale auftreten, und ob diese bestehenden Klimaregeln entsprechen und als Anpassungen an unterschiedliche Höhenlagen gedeutet werden können.An 114 Trauertyrannen und 138 Anis aus fünf verschiedenen Höhenstufen zwischen 0 und 2300 m über dem Meere wurden jeweils 15 Einzelmerkmale (Maße und Gewichte) registriert.Beide Vogelarten zeigten ein mit der Höhe deutlich ansteigendes Körpergewicht und entsprechend zunehmende Körperlänge.Für Herz und Lungen wurde eine im Verhältnis zum Körpergewicht stark überproportionale Gewichtszunahme mit der Höhe festgestellt.Spannweite und Länge der Flügel wuchsen ungefähr der Körpergröße entsprechend. Die Flächenbelastung blieb mit steigender Höhe gleich, was bei Berücksichtigung der Dimensionsunterschiede eine überproportionale Flügelflächenzunahme in Vergleich zum Gewichtsanstieg bedeutet.Der Schwanz wurde beim Trauertyrann schwach unter-, beim Ani leicht überproportional mit zunehmender Höhe länger.Der Schnabel wurde beim Trauertyrann im gleichen Verhältnis wie der Körper vergrößert, hingegen war er beim Ani in den Stufen IV und V sogar etwas kürzer als auf Meeresniveau.Das Beinskelett (Femur, Tibiotarsus, Tarsometatarsus) der Trauertyrannen wurde mit zunehmender Höhe im Vergleich zum Körper schwach unterproportional verlängert. Das Verhältnis der Einzelknochen änderte sich dabei nicht. Dagegen nahm es beim Ani kaum zu, und sein Tarsometatarsus wurde mit zunehmender Höhe relativ kürzer.Humerus und Ulna wuchsen mit der Höhe gleichmäßig, doch schwach unterproportional zur Körpergröße. Durch überproportionale Zunahme der längsten Schwungfeder glich sich dies Defizit an der Gesamtflügellänge wieder aus.Die meisten Veränderungen lassen sich als Anpassungen an die mit der Höhe abnehmenden Klimafaktoren Temperatur und Luftdruck deuten. So entspricht die Größenzunahme mit abnehmender Temperatur derBergmannschen, die relative Verkürzung der Beine derAllenschen, die überproportionale Zunahme der Herzgewichte derHesseschen Klimaregel. Vergrößerung von Herz und Lungen können als Adaption an notwendig höhere Stoffwechselleistung bei höherem Wärmeverlust, Fliegen in dünnerer Luft und geringeren Sauerstoffgehalt der Atemluft gedeutet werden.Das geringe Alter der Populationen in größeren Höhen und die enge Nachbarschaft zu solchen tieferer Lagen machen es sehr unwahrscheinlich, daß die gefundenen Unterschiede genetisch fixiert sind. Eine Aufgliederung der beiden Arten in Vertikalrassen bleibt daher außer Betracht.

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The adaptation to different altitudes byTyrannus melancholicus undCrotophaga ani in the Colombian Andes

Summary Two species of birds, the tropical kingbird,Tyrannus melancholicus Vieillot (1819) and the smooth-billed ani,Crotophaga ani L., 1758 were studied to determine whether or not some of their morphological characters showed adaptation to different altitudes in the Colombian Andes.Fifteen different measurements and weights were taken from each of 114 tropical kingbirds and 138 anis collected at five different elevations between 0 and 2300 m.Both species showed a clear increase in body weight and a corresponding increase in body length with altitude.The weights of heart and lungs increased at a much higher rate than did body weight.Spread and lenght of wings showed a nearly proportional increase with body length. No significant change was observed in the wing load. This means a relative increase in wing area compared with the increase in body weight.InTyrannus tail length increased rather more slowly with altitude than did body length, in the ani rather more rapidly.InTyrannus the bill increased proportionally with body length whereas in the ani the bill was even shorter at the higher levels IV and V than at sea level.In the kingbird's hind limb a general increase in femur, tibiotarsus and tarsometatarsus size was observed but no significant changes in their ratio could be detected. The same was not true in the ani: its hind limb increased less and its tarsometatarsus became relatively shorter with increasing altitude.Humerus and ulna increased with equal ratios with altitude but rather underproportionally. This was balanced by a larger increase of the longest wing feather.Most of the changes observed may be adaptive to decreasing temperature and atmospheric pressure with increasing altitude. Increasing size with decreasing temperature is in accordance withBergmanns rule, the relative decrease in leg length confirmsAllens, the increase of heart weightHesses eco-geographic rule. Increased weight of heart and lungs may be adaptive to increased heat loss, higher energy consumption during flight in thinner air, and lower oxygen concentration at higher altitudes.The higher altitudes have been settled by anis and tropical kingbirds only recently, and are in close proximity to the lower altitude ranges. Thus it seems unlikely that the variations of the characters between the different levels have a genetic basis, and although these variations may be as large as between verticals subspecies, such taxonomic distructions are not concluded in this instance.

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Meinem verehrten Doktorvater, Herrn Professor Dr.G. Niethammer, in dankbarer Erinnerung     

A ple?otropic acid phosphatase-deficient mutant of Escherichia coli shows premature termination in the dsbA gene. Use of dsbA :: phoA furions to localize a structurally important domain in DsbA

An Arabidopsis thaliana cDNA library was used to complement Saccharomyces cerevisiae pyrimidine auxotrophic mutants. Mutants in all but one (carbamylphosphate synthetase) of the six steps in the de novo pyrimidine biosynthetic pathway could be complemented. We report here the cloning, sequencing and computer analysis of two cDNAs encoding the aspartate transcarbamylase (ATCase; EC 2.1.3.2) and orotate phosphoribosyltransferase-orotidine-5-phosphate decarboxylase (OPRTase-OMP-decase; EC 2.4.2.10, EC 4.1.1.23) enzymes. These results confirm the presence in A. thaliana of a bifunctional gene whose product catalyses the last two steps of the pyrimidine biosynthetic pathway, as previously suggested by biochemical studies. The ATCase encoding cDNA sequence (PYRB gene) shows an open reading frame (ORF) of 1173 by coding for 390 amino acids. The cDNA encoding OPRTase-OMPdecase (PYRE-F gene) shows an ORF of 1431 by coding for 476 amino acids. Computer analysis of the deduced amino acid sequences of both cDNAs shows the expected high similarity with the ATCase, ornithine transcarbamylase (OTCase; EC 2.1.3.3), OPRTase and OMPdecase families. This heterospecific cloning approach increases our understanding of the genetic organization and interspecific functional conservation of the pyrimidine biosynthetic pathway and underlines its usefulness as a model for evolutionary studies.