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[Characteristics of the cytodifferentiation of omega-particle symbiotic bacteria from the micronucleus of Paramecium caudata clone M1-48].

The structure of the omega-particle-bacteria, growing in the micronucleus of Paramecium caudatum (Ciliata, Protozoa), was studied by electrom microscopy in the course of their life cycle. The cytoplasm of the spindle-shaped vegetative cells contains a large number of dense particles and transparent regions comprising the fibrillar material. Such cells, via several intermediate stages, are transformed into elongated twisted cells that are regarded as spores. The spore consists of two parts: homogeneous, and that containing the membrane system and rounded light bodies. The membranes are often double and connected with the fibrils. The cell wall is constructed, during all stages, of the outer membrane layer and the inner electron-dense layer.

Bacteria↗

[Infracommunity of parasite helminths of Ambystoma lernaensis (Caudata: Ambystomatidae) in Lerma, Mexico].

The helminth infracommunity structure was analyzed in 48 salamanders (Ambystoma lermaensis) from San Pedro Tlaltizapán, Lerma, Estado de Mexico (June 1997 to March 1999). Richness (2.46 +/- 1.8), abundance (29.5 +/- 42.3), and diversity (0.64 +/- 0.58) levels characterize these communities as depauperate, similar to other amphibian helminth communities worldwide. Apparently, the main forces determining infracommunity structure are ectothermy (as regulator of the ingestion rate), and the opportunistic feeding habits of the hosts, because 80% of the helminth taxa enter the host by ingestion of intermediate hosts.

Ambystoma↗

Intermediate heterochromatic zones in Triturus (Amphibia: Caudata).

Employment of the C-banding procedure disclosed the presence of slightly stained bands in some chromosome regions of several Triturus species. These regions have been previously described in other organisms as 'grey C-bands'. Possible explanations for the presence of these bands in Triturus karyotypes are discussed.

Animals↗

Analysis of HMW glutenin subunits and their coding sequences in two diploid Aegilops species.

Considerable progress has been made in understanding the structure, function and genetic regulation of high-molecular-weight (HMW) glutenin subunits in hexaploid wheat. In contrast, less is known about these types of proteins in wheat related species. In this paper, we report the analysis of HMW glutenin subunits and their coding sequences in two diploid Aegilops species, Aegilops umbellulata (UU) and Aegilops caudata (CC). SDS-PAGE analysis demonstrated that, for each of the four Ae. umbellulata accessions, there were two HMW glutenin subunits (designated here as 1Ux and 1Uy) with electrophoretic mobilities comparable to those of the x- and y-type subunits encoded by the Glu-D1 locus, respectively. In our previous study involving multiple accessions of Ae. caudata, two HMW glutenin subunits (designated as 1Cx and 1Cy) with electrophoretic mobilities similar to those of the subunits controlled by the Glu-D1 locus were also detected. These results indicate that the U genome of Ae. umbellulata and the C genome of Ae. caudata encode HMW glutenin subunits that may be structurally similar to those specified by the D genome. The complete open reading frames (ORFs) coding for x- and y-type HMW glutenin subunits in the two diploid species were cloned and sequenced. Analysis of deduced amino acid sequences revealed that the primary structures of the x- and y-type HMW glutenin subunits of the two Aegilops species were similar to those of previously published HMW glutenin subunits. Bacterial expression of modified ORFs, in which the coding sequence for the signal peptide was removed, gave rise to proteins with electrophoretic mobilities identical to those of HMW glutenin subunits extracted from seeds, indicating that upon seed maturation the signal peptide is removed from the HMW glutenin subunit in the two species. Phylogenetic analysis showed that 1Ux and 1Cx subunits were most closely related to the 1Dx type subunit encoded by the Glu-D1 locus. The 1Uy subunit possessed a higher level of homology to the 1Dy-type subunit compared with the 1Cy subunit. In conclusion, our study suggests that the Glu-U1 locus of Ae. umbellulata and the Glu-C1 locus of Ae. caudata specify the expression of HMW glutenin subunits in a manner similar to the Glu-D1 locus. Consequently, HMW glutenin subunits from the two diploid species may have potential value in improving the processing properties of hexaploid wheat varieties.

Amino Acid Sequence↗

Variations in a hotspot region of chloroplast DNAs among common wheat and Aegilops revealed by nucleotide sequence analysis.

The second largest BamHI fragment (B2) of the chloroplast DNA in Triticum (wheat) and Aegilops contains a highly variable region (a hotspot), resulting in four types of B2 of different size, i.e. B2l (10.5kb), B2m (10.2kb), B2 (9.6kb) and B2s (9.4kb). In order to gain a better understanding of the molecular nature of the variations in length and explain unexpected identity among B2 of Ae. ovata, Ae. speltoides and common wheat (T. aestivum), the nucleotide sequence between a stop codon of rbcL and a HindIII site in cemA in the hotspot was determined for Ae. ovata, Ae. speltoides, Ae. caudata and Ae. mutica. The total number of nucleotides in the region was 2808, 2810, 3302, and 3594 bp, for Ae. speltoides, Ae. ovata, Ae. caudata and Ae. mutica, respectively, and the sequences were compared with the corresponding ones of Ae. crassa 4x, T. aestivum and Ae. squarrosa. Compared with the largest B2l fragment of Ae. mutica, a 791bp and a 793 bp deletion were found in Ae. speltoides and Ae. ovata, respectively, and the possible site of deletion in the two species is the same as that of T. aestivum. However, a deleted segment in Ae. ovata is 2 bp longer than that of Ae. speltoides (and T. aestivum), demonstrating that recurrent deletions had occurred in the chloroplast genomes of both species. Comparison of the sequences from Ae. caudata and Ae. crassa 4x with that of Ae. mutica revealed a 289 bp and a 61 bp deletion at the same site in Ae. caudata and Ae. crassa 4x, respectively. Sequence comparison using wild Aegilops plants showed that the large length variations in a hotspot are fixed to each species. A considerable number of polymorphisms are observed in a loop in the 3' of rbcL. The study reveals the relative importance of the large and small indels and minute inversions to account for variations in the chloroplast genomes among closely related species.

Base Sequence↗

[Clinico-electroencephalographic indices of the parkinsonian syndrome induced by MPP+ in rats].

The bilateral intranigral injection of 1-methyl-4-phenyl-pyridinium ion (MPP+) (10 g) produced significant oligokinesia, rigidity and weak tremor in rats. The extrapyramidal disturbances manifest a high-amplitude paroxysmal activity (PA) in the structures studied. It was found that the Pa was remarkable and more stable in the caudata nucleus than in other brain structures. It is PA that gives us the real basis to conclude the formation of the generator of pathologically enhanced excitation (GPEE) in the caudata nuclei. The analysis of PA dynamics revealed that the formation of the GPEE in the caudata nuclei correlated with development of parkinsonian syndrome (PS).

1-Methyl-4-phenylpyridinium↗

[Precipitation reactions between secretory products in amphibian oviducts].

The existence of precipitin reactions between some molecules in egg jellies (oviduct secretions) of tailed amphibians (Amphibia caudata) has been demonstrated by double diffusion on agarose plates. These reactions do not exist in frogs and toads (Amphibia salientia). One precipitin reaction was related to compounds with a common molecular site of interaction for all A. caudata: all cross-species reactions were possible; a common antigenic rate has been shown. Another precipitin reaction, positively demonstrated in Pleurodeles waltl, probably exists in other A. caudata. The putative influence of these reactions on egg jelly-spermatozoon interactions has been discussed. An homology between these intra-egg jelly reactions and cortical granule content-egg jelly reactions in A. salientia has been suggested.

Amphibians↗

Epinephrine, norepinephrine and dopamine concentrations in amphibian brain.

The whole brain concentrations of epinephrine, norepinephrine and dopamine in North American amphibians, orders Caudata and Salientia, are reported. Epinephrine is the major catecholamine in the Salientia while norepinephrine and epinephrine concentrations are roughly equivalent in suborders of Caudata. Relative regional concentrations are similar to other classes (mammals, reptiles and birds) although the absolute concentration of epinephrine is considerably higher in amphibians than in most other species.

Amphibians↗

Distribution of blue-sensitive photoreceptors in amphibian retinas.

Previously, we reported that an opsin (Rc-MS) belonging to the SWS2 group opsins is expressed in bullfrog green rods [Hisatomi, O. et al., FEBS Lett., 1999, 447, 44-48]. An anti-Rc-MS antiserum recognized the cones of the Japanese common newt, Cynops pyrrhogaster, which has no green rods. We isolated a cDNA encoding an SWS2 group opsin (Cp-SWS2) from this newt and found that Cp-SWS2 is expressed in a small population of the cones. Our results suggest that SWS2 opsins can be expressed in either green rods or cones of caudata. It seems reasonable to suppose that green rods arose before amphibia were divided into caudata and anura.

Amino Acid Sequence↗

Effects of euxanthone on neuronal differentiation.

The growth inhibitory and differentiation inducing effects of euxanthone (1,7-dihydroxyxanthone) from the medicinal plant Polygala caudata on the neuroblastoma (Neural 2A, subclone BU-1) were investigated. At the concentration range of 0-100 microM, euxanthone inhibits the growth of BU-1 cells in a dose dependent manner. The 50% growth inhibitory concentration (IC50) was 41 microM. Significant induction of morphological differentiation and neurite growth was observed at the concentration of 100 microM. Frequency of proliferative neuroblastoma cells was determined after induction of differentiation. The frequency of proliferating BU-1 cells was markedly reduced from 1/1.1 to <1/99. Confocal microscopy also confirmed that the morphological differentiation of BU-1 was associated with the expression of neurite specific marker MAP-2 protein in neurites. These data suggest that euxanthone may be one of the neuropharmacological active compounds in the medicinal plant Polygala caudata.

Animals↗

Polypeptide chain composition diversity of hexagonal-bilayer haemoglobins within a single family of annelids, the alvinellidae.

Following previous analysis of the structure of Alvinella pompejana heaxagonal-bilayer haemoglobin (HBL Hb) [1], we report in this paper the structure of three other HBL Hbs belonging to Alvinella caudata, Paralvinella grasslei and Paralvinella palmiformis, members of the Alvinellidae, annelid family strictly endemic to deep-sea hydrothermal vents located on the ridge crests in the Pacific ocean. The multi-angle laser light scattering (MALLS) and fast protein liquid chromatography (FPLC) analysis revealed a broad range of molecular masses for the extracellular Hb molecules, 3517 +/- 14 kDa (A. caudata), 3822 +/- 28 kDa (P. grasslei) and 3750 +/- 150 kDa (P. palmiformis). Native and derivative Hbs (reduced, carbamidomethylated and deglycosylated) were analysed by electrospray ionization mass spectroscopy (ESI-MS) and the data was processed by the maximum entropy deconvolution system (MaxEnt). The most important difference between alvinellid HBL Hbs was the variation in their composition, from two to four monomeric globin chains, and from one to four linker chains. Therefore, despite the fact that all these species belong to a single family, notable differences in the polypeptide chain composition of their HBL Hbs were observed, probably accounting for their different functional properties as previously reported by this group Toulmond, A., El Idrissi Slitine, F., De Frescheville, J. & Jouin, C. (1990) Biol. Bull. 179, 366-373.

Animals↗

Efficiency of playback for assessing the occurrence of five bird species in Brazilian Atlantic Forest fragments.

Playback of bird songs is a useful technique for species detection; however, this method is usually not standardized. We tested playback efficiency for five Atlantic Forest birds (White-browed Warbler Basileuterus leucoblepharus, Giant Antshrike Batara cinerea, Swallow-tailed Manakin Chiroxiphia caudata, Whiteshouldered Fire-eye Pyriglena leucoptera and Surucua Trogon Trogon surrucura) for different time of the day, season of the year and species abundance at the Morro Grande Forest Reserve (South-eastern Brazil) and at thirteen forest fragments in a nearby landscape. Vocalizations were broadcasted monthly at sunrise, noon and sunset, during one year. For B. leucoblepharus, C. caudata and T. surrucura, sunrise and noon were more efficient than sunset. Batara cinerea presented higher efficiency from July to October. Playback expanded the favourable period for avifaunal surveys in tropical forest, usually restricted to early morning in the breeding season. The playback was efficient in detecting the presence of all species when the abundance was not too low. But only B. leucoblepharus and T. surrucura showed abundance values significantly related to this efficiency. The present study provided a precise indication of the best daily and seasonal periods and a confidence interval to maximize the efficiency of playback to detect the occurrence of these forest species.

Animals↗

[Phylogenetic relationships and intraspecific variation of D-genome Aegilops L. as revealed by RAPD analysis].

RAPD analysis was carried out to study the genetic variation and phylogenetic relationships of polyploid Aegilops species, which contain the D genome as a component of the alloploid genome, and diploid Aegilops tauschii, which is a putative donor of the D genome for common wheat. In total, 74 accessions of six D-genome Aegilops species were examined. The highest intraspecific variation (0.03-0.21) was observed for Ae. tauschii. Intraspecific distances between accessions ranged 0.007-0.067 in Ae. cylindrica, 0.017-0.047 in Ae. vavilovii, and 0.00-0.053 in Ae. juvenalis. Likewise, Ae. ventricosa and Ae. crassa showed low intraspecific polymorphism. The among-accession difference in alloploid Ae. ventricosa (genome DvNv) was similar to that of one parental species, Ae. uniaristata (N), and substantially lower than in the other parent, Ae. tauschii (D). The among-accession difference in Ae. cylindrica (CcDc) was considerably lower than in either parent, Ae. tauschii (D) or Ae. caudata (C). With the exception of Ae. cylindrica, all D-genome species--Ae. tauschii (D), Ae. ventricosa (DvNv), Ae. crassa (XcrDcrl and XcrDcrlDcr2), Ae. juvenalis (XjDjUj), and Ae. vavilovii (XvaDvaSva)--formed a single polymorphic cluster, which was distinct from clusters of other species. The only exception, Ae. cylindrica, did not group with the other D-genome species, but clustered with Ae. caudata (C), a donor of the C genome. The cluster of these two species was clearly distinct from the cluster of the other D-genome species and close to a cluster of Ae. umbellulata (genome U) and Ae. ovata (genome UgMg). Thus, RAPD analysis for the first time was used to estimate and to compare the interpopulation polymorphism and to establish the phylogenetic relationships of all diploid and alloploid D-genome Aegilops species.

Genome, Plant↗