Meiotic studies ofElymus nutans andE. jacquemontii (Poaceae,Triticeae) and their hybrids withPseudoroegneria spicata and seventeenElymus species

Hybridizations ofElymus nutans andE. jacquemontii were carried out with one species ofPseudoroegneria (S genome), and 20Elymus species, each containing either of the SH, SY, SYH, or SYW genomes. Chromosome configurations were analysed at metaphase I of the two target taxa and their interspecific hybrids. It is concluded that (i)E. nutans is an allohexaploid containing the SYH genomes, andE. jacquemontii is an allotetraploid having the SY genomes; (ii) the genomic affinity is associated with the geographic distance between the species studied; (iii) minor genomic structural rearrangements have occurred within the hexaploid taxon ofE. nutans.     

Cytological analysis on the distribution and origin of the alien chromosome pair conferring blue aleurone color in several European common wheat (Triticum aestivum L.) strains

Summary Meiotic chromosome pairing and Giemsa C-banding analyses in crosses of several European blue-grained wheat strains with Chinese Spring double ditelosomic and other aneuploid lines showed that Triticum aestivum Blaukorn strains Berlin, Probstdorf, Tschermak, and Weihenstephan are chromosome substitutions, in which the complete wheat chromosome 4A pair is replaced, whereas the strains Brünn and Moskau are 4B substitutions. The alien chromosome pair in all of these strains is an A genome chromosome (4A) from diploid Triticum monococcum or T. boeoticum not present in common tetraploid and hexaploid cultivated wheats. The Blaukorn strain Weihenstephan W 70a86 possesses, in addition to a rye chromosome pair 5R compensating for the loss of part of chromosome 5D, a 4A/5DL translocation replacing chromosome pair 4B of wheat.     

The base-alteration spectrum of spontaneous and ultraviolet radiation-induced forward mutations in the URA3 locus of Saccharomyces cerevisiae

Summary A forward mutation system has been developed to obtain rapidly clonable mutants at the URA3 locus in yeast by means of selection for 5-fluoroorotic acid resistance. We have used this system to determine base changes in 35 spontaneous and 34 ultraviolet radiation-induced ura3 base substitution mutants. Other mutants (frameshift, deletion, duplication, replacement) were detected as well. Evidence is reported which suggests cyclobutane dimers are the principal mutagenic lesions induced by UV radiation in stationary phase cells of the yeast Saccharomyces cerevisiae. Since most of the induced lesions are at 5-TT-3 sites, the results suggest that the A-rule, preferential insertion of adenine residues opposite poorly pairing sites in DNA, does not apply for yeast cells irradiated in stationary phase, whereas the spontaneous mutation data indicate that the A-rule applies for cells in logarithmic phase. Most of the spontaneous mutations are transversions. UV-induced transitions and transversions occur at approximately equal frequencies.     

Characterization of two beta-tubulin genes from Geotrichum candidum.

Summary The -tubulin genes G1 and G2 from the phytopathogenic hemiascomycete Geotrichum candidum were found to be highly diverged in amino acid sequence from those of other filamentous fungi. G1 and G2 were also divergent from each other, with the coding regions sharing only 66% nucleotide sequence homology and 64% amino acid identity. However, the proteins shared 82% similarity and only 25 of the 161 non-identical amino acid substitutions were non-conservative. The organization of G1 is similar to other fungal -tubulin genes, but G2 has several unusual features; it has 2 amino acid additions in the N-terminal 40 residues and must employ an uncommon 5 splice junction sequence in preference to an overlapping perfect consensus. The amino acid change found to confer benomyl resistance in Neurospora crassa was also present in G2. G1 has four introns which are located similarly to those of -tubulin genes in other fungi. G2, however, has a single intron in a unique location. Translational fusions employing the 5 non-coding regions of the two Geotrichum -tubulin genes were made with the hygromycin phosphotransferase gene and shown to function in Schizosaccharomyces pombe and Trichoderma hamatum. However, G. candidum could not be transformed with these or other tested plasmids commonly used for fungal transformation.     

Regeneration of fertile plants from protoplasts of different Arabidopsis thaliana genotypes

Summary A protocol for obtaining regenerated fertile plants from mesophyll protoplasts of Arabidopsis thaliana is reported. Protoplasts were isolated from leaves of 21-to 28-day-old Arabidopsis plants grown in a controlled environment. Sustained divisions were achieved when protoplasts were embedded in beads formed by 1.4% sodium alginate in the presence of 50mM CaCl₂ in 0.4 mannitol, which was then exchanged againts modified B5 medium. About 0.4%–0.6% of the protoplasts developed into colonies of which 80%–90% formed shoots and subsequently regenerated to fertile plants. Seeds harvested from more than 200 independently regenerated plants were sown and germination frequencies of more than 95% were obtained. Furthermore, the F₁ plants did not show any evidence of somaclonal variation on visual inspection. This protocol was originally developed for Arabidopsis thaliana Columbia; however it was shown to be applicable also for the genotypes Wassilewskija, Landsberg erecta and Estland though with differing efficiencies.Abbreviations FDA fluorescein diacetate - CM culture medium - SRM shoot regeneration medium - SEM shoot elongation medium - RM rooting medium - PE plating effciency - NAA -naphthaleneacetic acid - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - IBA indole-3-butyric acid - BAP 6-benzylaminopurine - Kin kinetin - 2-iP 2-isopentenyladenine - GA₃ gibberetic acid     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Conformational Change of the Rieske [2Fe–2S] Protein inCytochrome bc 1 Complex

Structures of mitochondrial bc ₁ complex have been reported based on four different crystalforms by three different groups. In these structures, the extrinsic domain of the Rieske [2Fe–2S]protein, surprisingly, appeared at three different positions: the c ₁ position, where the [2Fe–2S]cluster exists in close proximity to the heme c ₁; the b position, where the [2Fe–2S] clusterexist in close proximity to the cytochrome b; and the intermediate position where the[2Fe–2S] cluster exists in between c ₁ and b positions. The conformational changes betweenthese three positions can be explained by a combination of two rotations; (1) a rotation of theentire extrinsic domain and (2) a relative rotation between the cluster-binding fold and thebase fold within the extrinsic domain. The hydroquinone oxidation and the electron bifurcationmechanism at the Q_P binding pocket of the bc ₁ complex is well explained using theseconformational changes of the Rieske [2Fe–2S] protein.     

Die Homologie des Perigons der Zingiberaceen Ein Beitrag zur Morphologie und Phylogenie des Monokotylen-Perigons

Nicolaia elatior is used as an example to demonstrate that the mucronate tepals ofZingiberaceae correspond to hypsophylls (bracts) consisting of a leaf sheath and a rudimentary Oberblatt (= leaf petiole + lamina) represented by the mucro. Evidence for this interpretation is furnished by all available criteria: leaf sequence (exhibiting a complete continuum of forms from foliage leaves over cata- and hypsophylls to the tepals), nervature, and ontogeny.The present conception is compared with the well-founded thesis ofLeinfellner that the perigone ofLiliaceae is derived from the androecium. The different morphological status of the perigone in both families is not regarded as the result of different phylogenetic origin, but as a manifestation of morphogenetic transgressions from one phyllome category to an adjacent one: In theLiliaceae the perigone is under a strong morphogenetic influence of the androecium, and therefore displays staminal characters, in theZingiberaceae it is under the dominating influence of the extrafloral region, and thus appears as a hypsophyllous structure. If this assumption of a morphologically oscillating perigone is correct, it will be fundamentally impossible to demonstrate unequivocally the phylogenetic origin of the monocotyledonous perigone.

Im wissenschaftlichen Werk Prof. Dr.Walter Leinfellners steht an erster Stelle die Morphologie der Blütenorgane. Als sein dankbarer Schüler möchte ich ihm aus Anlaß seines 70. Geburtstages die folgende Studie zu einem Thema zueignen, das ihn wie mich gleichermaßen angesprochen hat und schon Gegenstand der Forschungsarbeit des Jubilars war: die Homologie des Monokotylen-Perigons.     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

Subtle behavioral variation in wild chimpanzees, with special reference to Imanishi’s concept of kaluchua

Here we consider the concept of kaluchua (a word adopted from the English culture) in group-living animals developed by Imanishi in the 1950s. He distinguished it from bunka (the Japanese equivalent to the English culture) because he thought that bunka had strong connotations of noble and intellectual human-like activities. Although he did not rigidly define kaluchua, his original concept of kaluchua was much broader than bunka and represented non-hereditary, acquired behavior that was acknowledged socially. However, instead of social life, complex feeding skills have often formed the central topic in the current studies of animal culture. In order to provide evidence that more subtle behavioral variations exist among wild chimpanzee (Pan troglodytes) populations, we directly compared the behaviors of two well-habituated chimpanzee groups, at Bossou and Mahale. During a 2-month stay at Bossou, M.N. (the first author) saw several behavioral patterns that were absent or rare at Mahale. Two of them, mutual genital touch and heel tap were probably customary for mature females and for mature males, respectively. Index to palm and sputter are still open to question. These subtle patterns occurred more often than tool use during the study period, suggesting that rarity is not the main reason for their being ignored. Unlike tool use, some cultural behavioral patterns do not seem to require complex skills or intellectual processes, and sometimes it is hard to explain the existence of such behaviors only in terms of function.     

Induction,polarity and spatial control of cytokinesis in some abnormal subsidiary cell mother cells ofZea mays

Summary Cytokinesis in the subsidiary cell mother cells (SMCs) ofZea mays leaves grown in the presence of 5 mM of caffeine solution is usually partially inhibited. A continuous wall strip, resembling a portion of the subsidiary cell (SC) wall, is laid down in the preprophase microtubule band (PMB) cortical zone. Sometimes, the incomplete SC (SC) wall grows centripetally in the absence of a phragmoplast and the gap becomes smaller or closes. The SC nucleus escapes through the SC wall gap into the larger SMC compartment and may fuse with the other nucleus.The aberrant SMCs (a-SMCs) pass through another division cycle, reattempting to produce a SC. A typical PMB is found in the SC space, in the site of the previous PMB. Moreover, in some preprophase SMCs, the cytoplasm adjacent to the SC wall is traversed by a small number of microtubules. The preprophase nuclei are partly or totally separated from the PMB by the perforated SC wall and may lie far from the latter.Usually, one mitotic spindle is assembled. The cycling paired polarized nuclei appear to synchronize and their chromosomes line up together on a single metaphase plate. Although the mitotic spindle axis is diversely oriented, one of its poles tends to be stabilized in the proximity of the SC wall gap. These divisions separate abnormal cells. Most or all the cell plate edges fuse with wall regions far from the PMB cortical zone. However, when some of them approach the SC wall strips, they are attracted and intersect their rims. In rare occasions the cell plate, invading the SC space is guided by the PMB cortical zone to create a SC-like curved wall portion, in absence of a daughter nucleus.Observations show that the cell plate arrangement in redividing aberrant SMCs is not subjected to a strict spatial control. The disorder of polarization sequence generated by the SC wall ring and especially the perturbation of the spatial (and functional?) relationship between PMB-PMB cortical zone and the nucleus—mitotic spindle is a causal factor of the variable cell plate arrangements.     

Partial characterization of anrpoD-like gene oflactoccocus lactis subsp.lactis ML3 with a polymerase chain reaction-based approach

With degenerated oligonucleotide primers for conserved regions of bacterial sigma factor proteins, a 117-bp internal DNA fragment of anrpoD-like gene ofLactoccocus lactis subsp.lactis ML3 was amplified by the polymerase chain reaction (PCR). The DNA sequence of this PCR product was determined by cycle sequencing, and the deduced amino acid sequence of this internal fragment showed an extensive homology with the known sigma factor sequences from six other microorganisms and present a 13-amino acid region corresponding to the typical RpoD box of primary sigma factors. This PCR product was used as a probe to specifically detect sigma homologs inPediococcus acidilactici, Leuconostoc lactis, Lactobacillus helveticus, Lactobacillus acidophilus, Enterococcus faecalis, Streptococcus thermophilus, andLactococcus lactis subsp.cremoris. These data are consistent with the existence of a high similarity between the primary sigma factors from diverse Gram-positive microorganisms.     

Meiotic analysis ofElymus caucasicus,E. longearistatus,and their interspecific hybrids with twenty-threeElymus species (Triticeae,Poaceae)

Interspecific hybridizations were carried out between the two tetraploidsElymus caucasicus andE. longearistatus, and 23 tetraploids and hexaploids ofElymus containing SH, SY, SYH, and SYW genomes and representing various geographical regions. Meiotic pairing was studied in the two target species and their hybrids. It is concluded from this study that (i) interspecific hybridization is fairly easy to perform although strong reproductive barriers exist between the species; (ii)Elymus caucasicus andE. longearistatus are allotetraploids, and share the diverged SY genomes; (iii) the divergence of SY genomes is correlated with the geographic distance between theElymus spp. studied.     

Cytogenetic studies of the intergeneric hybrids between Secale cereale and Elymus caninus,E. brevipes,and E. tsukushiensis (Triticeae: Poaceae)

Summary Integeneric hybridizations were carried out between Secale cereale L. (2n = 14, RR) and three Elymus species, namely, E. caninus (L.) L. (2n = 28, SSHH), E. brevipes (Keng) Löve (2n = 28, SSYY) and E. tsukushiensis Honda (2n = 42, SSHHYY). Chromosome pairing was studied at metaphase I in the parental species and the hybrids. Meiotic configurations of the hybrids were 20.74 1+0.14 II for E. caninus x S. cereale (SHR), 16.35 I+2.17 II+0.09 III for E. brevipes x S. cereale (SYR) and 25.84 I+1.10 II+0.02 III for E. tsukushiensis x S. cereale (SHYR), in addition to some secondary associations in the different hybrids. It is concluded from the study that (1) a certain, different homoeologous relationship exists among S, H and Y genomes in the investigated Elymus species; (2) low homoeology is present between genomes of Elymus (S or H or Y) and rye (R); (3) the Secale genome affects homoeologous chromosome pairing between different genomes in E. brevipes and E. tsukushiensis.     

Three different types of organization of the vir regulon in group A streptococci

Summary The DNA of group A streptococci (GAS) encodes several important virulence factors such as the antiphagocytic M protein, the Ig-Fc-binding M-related proteins (FcrA-like and EnnX-like) and the complement factor-inactivating C5a peptidase. The corresponding genes emm, fcrA, ennX, and scpA, respectively, were assumed to be located close together in the GAS genome. Additionally, emm and scpA have been found to be under the positive, coordinate control of the virR locus, which led to the designation vir regulon for the corresponding genomic segment. In order to map the vir regulons of many GAS serotypes and to analyse any correlation between the organization of vir regulons and circumscribed heterogeneities within the emm, virR, and scpA genes, an approach using several distinct sets of polymerase chain reaction (PCR) experiments was chosen. By examination of the genomic DNA of 42 GAS isolates from 36 different M serotypes three patterns of vir regulon topography were found. The first, designated large vir regulon (LVR), consists of virR -fcrA(-like) emm - ennX(-like) - scpA. The second, designated small vir regulon (SVR), contains virR - emm- scpA, and the last, designated unusual vir regulon (UVR), resembles SVR but contains additional heterogeneous sequences between emm and scpA. The patterns correlate with heterogeneities at the 3 ends of the virR and scpA genes, with the M classification system and the occurrence of specific non-coding intervening sequences within the vir regulons. The potential impact of these patterns on models to account for generation of vir regulons is discussed.     

Memorization and delayed expression of regulatory messages in plants

Plantlets of Bidens pilosus L., considered to be basically symmetrical, can be lateralized (A/B) by being administered a symmetry-breaking signal such as puncturing one of the plant cotyledons. The induced asymmetry remains latent as long as the plants have not been made permissive, i.e. as long as the plant apex is left functioning. When the apex has been removed (plant decapitation), the latent asymmetry is expressed by one of the cotyledonary buds (a/b) statistically beginning to elongate before the other. The interval of time between delivering the symmetry-breaking signal and making the plant permissive is the memorization-time, t. Memorization can be quantified by using a precedence index, q, the values of which range from 0 (no detectable asymmetry with regard to bud growth) to ±1 (bud growth perfectly asymmetric in favour of either bud b or a). Even for memorization times, t, up to 14 d, q-values up to 0.4 (or even larger) are observed. Various experimental characteristics (e.g. light, temperature, presence or absence of the root system) but not the plant age can affect the q-values, at the moment when the treatments are performed, at least in the range of 6 to 25 d. Combining several puncturing treatments either increases or decreases the q-values, depending on the nature of these treatments and the time-intervals, t, between them. Symmetrically removing both cotyledons in the minutes following the puncturing of one of them does not significantly alter the results, which means that the symmetry-breaking message is rapidly transported and memorized within the plant. Non-traumatic asymmetrical treatments (droplets of saline solutions, light-gradients) can also act as symmetry-breaking signals and be memorized. Plants other than Bidens are likely to possess similar memorization ability, although the q-values observed up to now have not been very large.     

Altered genetic code in Paramecium mitochondria: Possible evolutionary trends

Summary The sequence and presumptive structure of a tRNA trp gene from Paramecium tetraaurelia are given. The gene is located 1,500 bp downstream from the 13S rRNA gene, in about the middle of the genome. Paramecium tRNA trp has a completely normal TC loop and stem, however its anticodon (UCA) constitutes an alteration in the universal genetic code, similar to those seen in fungal and mammalian mitochondria. Most features of Paramecium tRNA trp resemble other mitochondrial counterparts; however, its sequence is more homologous to the unaltered tRNA trp (anticodon CCA) from E. coli. Paramecium mitochondria may resemble a primitive stage of organelle evolution.     

Voltage dependence of the basolateral membrane conductance in theAmphiuma collecting tubule

Summary The basolateral potassium conductance of cells of most epithelial cells plays an important role in the transcellular sodium transport inasmuch as the large negative equilibrium potential of potassium across this membrane contributes to the electrical driving force for Na⁺ across the apical membrane. In the present study, we have attempted to establish, theI-V curve of the basolateral membrane of theAmphiuma collecting tubule, a membrane shown to be K⁺ selective. TransepithelialI-V curves were obtained in short, isolated perfused collecting tubule segments. The shunt conductance was determined using amiloride to block the apical membrane Na⁺ conductance. In symmetrical solutions, the shuntI-V curve was linear (conductance: 2.2±0.3 mS·cm^–2). Transcellular current was calculated by subtracting the shunt current from the transepithelial current in the absence of amiloride. Using intracellular microelectrodes, it was then possible to measure the basolateral membrane potential simultaneously with the transcellular current. The basolateral conductance was found to be voltage dependent, being activated by hyperpolarization: conductance values at –30 and –80 mV were 3.6±1.0 and 6.6±1.0 mS·cm^–2, respectively. BasolateralI-V curves were thus clearly different from that predicted by the constant field model. These results indicate that the K⁺-selective basolateral conductance of an amphibian collecting tubule shows inward (anomalous) rectification. Considering the electrogenic nature basolateral Na–K-pump, this may account for coupling between pump-generated potential and basolateral K⁺ conductance.     

Copper-containing nitrite reductase from Pseudomonas aureofaciens is functional in a mutationally cytochrome cd 1-free background (NirS−) of Pseudomonas stutzeri

The structural gene, nirK, for the respiratory Cu-containing nitrite reductase from denitrifying Pseudomonas aureofaciens was isolated and sequenced. It encodes a polypeptide of 363 amino acids including a signal peptide of 24 amino acids for protein export. The sequence showed 63.8% positional identity with the amino acid sequence of Achromobacter cycloclastes nitrite reductase. Ligands for the blue, type I Cu-binding site and for a putative type-II site were identified. The nirK gene was transferred to the mutant MK202 of P. stutzeri which lacks cytochrome cd ₁ nitrite reductase due to a transposon Tn5 insertion in its structural gene, nirS. The heterologous enzyme was active in vitro and in vivo in this background and restored the mutationally interrupted denitrification pathway. Transfer of nirK to Escherichia coli resulted in an active nitrite reductase in vitro. Expression of the nirS gene from P. stutzeri in P. aureofaciens and E. coli led to nonfunctional gene products. Nitrite reductase activity of cell extract from either bacterium could be reconstituted by addition of heme d ₁, indicating that both heterologous hosts synthesized a cytochrome cd ₁ without the d ₁-group.Abbreviations Cu-NIR Cu-containing nitrite reductase - DDC diethyldithiocarbamate - EPR electron paramagnetic resonance - IPTG isopropyl--D-galactoside - SDS sodium dodecyl sulfate - LB medium Luria-Bertani medium     

The plasma membrane H+-ATPase gene family in Arabidopsis: genomic sequence of AHA10 which is expressed primarily in developing seeds

The plasma membrane H+-ATPases in Arabidopsis thaliana represent the largest family of cation translocating P-type ATPases identified in plants or animals. We report here seven new isoforms, which were identified by polymerase chain reaction (PCR) amplification of genomic DNA. Amplifications were performed with degenerate primers corresponding to two short conserved sequence motifs (CSDK and GDGV) found in most P-type ATPases. A comparison was made of three CSDK-side primers, which were used either as totally degenerate mixtures or rendered less degenerate by substitution with deoxyinosine or fluorodeoxyuridine. Amplified genomic fragments were cloned, partially sequenced and shown to correspond to Arabidopsis genes by Southern blot analysis with gene-specific probes. One newly identified isoform, AHA10, was isolated as a cosmid clone and sequenced. The 5 and 3 ends of the gene were determined by comparison with the AHA10 cDNA sequence. AHA10 is the most divergent isoform characterized in the Arabidopsis family. AHA10 appears to be expressed primarily in developing seeds, as indicated by Northern blot analysis of AHA10 mRNA and by the analysis of transgenic plants expressing a -glucuronidase (GUS) reporter gene fused to an AHA10 promoter. Our results indicate that one function of this unusually large H⁺-ATPase gene family is to allow for expression of different isoforms in different cell types.