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At least 19 recordsLinked to original sources
PubMed1976

Perception as a possible source of conservation: evidence for length conservation.

In conservation problems, it is commonly assumed that equivalence judgments are not facilitated by observation of the stimuli following transformation. The reverse is usually assumed to be the case. These assumptions were tested in a training experiment. Perceptual counterparts of a series of conservation of length tests were presented to subjects who were catagorized as conservers or nonconservers on conservations of length pretests, and to conservers and nonconservers given conservation of length training. Perceptual performance of the untrained nonconservers was significantly worse than that of the other 3 groups, that is, trained nonconservers, untrained conservers, and trained conservers. These findings are interpreted as consistent with the hypothesis that conservation is attained with the support of perception, not in spite of it.

Child↗
PubMed1986

Conservation of kinetoplastid minicircle characteristics without nucleotide sequence conservation.

The nucleotide sequence and restriction fragment electrophoretic mobility of four minicircles from the kinetoplast DNA of Trypanosoma brucei were determined. Each minicircle possesses an approximately 130 base pair conserved sequence which occurs in other African trypanosome minicircles and contains a 13 base pair sequence that is conserved among kinetoplastid genera [Kidane et al. (1984) Gene 27, 265-277]. A sequence located adjacent to the conserved sequence conserves purine versus pyrimidine strand bias, but not nucleotide sequence, and contains periodic oligo(dA) tracts. Minicircle fragments containing the conserved sequence and adjacent segment exhibited anomalous electrophoretic mobility in polyacrylamide gels. The position of the oligo(dA) tracts in the fragments appears to influence this anomalous mobility. The presence of conserved features independent of conserved nucleotide sequence and the lack of conserved open reading frames among these minicircles suggests that minicircles may have a function other than encoding protein.

Animals↗
PubMed1991

Changing indications for breast conserving therapy: proportion of patients with operable breast cancer suitable for breast conservation.

The changes in indication for breast conserving therapy and the proportion of operable stage-I and stage-II breast cancers suitable for breast conserving therapy were studied in three time periods. The percentage of patients treated with breast conserving therapy gradually increased through the years: 77/199 (39%) in 1980-1981, 122/245 (50%) in 1985-1987, and 168/305 (55%) in 1987-1989. Using the actual selection criteria more patients might have been candidates for breast conserving therapy: 69, 64 and 59 per cent respectively. In the period 1987-1989 almost all patients who were considered good candidates for breast conserving therapy had a breast sparing procedure. Indications widened in relation to age limit (less than or equal to 70 years) and, over the years, more factors became relative contra-indications: very young age, presence of extensive intra-ductal component, data from mammography (multicentricity, size and aspect of the lesion). About 40 per cent of the patients were no appropriate candidates for breast conserving therapy. This percentage would be higher when operable stage-III patients would have been included.

Age Factors↗
PubMed1977

Semi-conservative and non-conservative replication of DNA in temperature-sensitive mouse L-cells.

The mode of DNA replication has been studied in wild-type mouse L-cells (WT-4) and in two subclones (TS A1S9 and ts C1 cells) which are temperature-sensitive in DNA synthesis. It has been demonstrated that DNA is replicated by the semi-conservative mechanism in WT-4 cells grown at 34 degrees C or at 38.5 degrees C throughout the logarithmic phase and into the stationary phase. Similar results were obtained with ts A1S9 and ts C1 cells grown at the permissive temperature (34 degrees C). When the latter cells were incubated at the non-permissive temperature (38.5 degrees C) inactivation of DNA synthesis appeared to proceed through three general stages. During the first 24 h after temperature upshift suppression of semi-conservative DNA replication occurred. During the second stage a very low level of semi-conservative synthesis was maintained. During the third stage, incorporation of dThd into DNA began to increase, often reaching 10-20% of control levels after 3-5 days. During this third stage DNA synthesis was effected by a non-conservative mechanism. Temperature-inactivated ts A1S9 cells and ts C1 cells were able to perform semi-conservative synthesis upon back-shift to 34 degrees C, using as template that DNA synthesized prior to temperature upshift.

Centrifugation, Density Gradient↗
PubMed2025

Conservation genomics of a threatened subtropical Rhododendron species highlights the distinct conservation actions required in marginal and admixed populations.

With the impact of climate change and anthropogenic activities, the underlying threats facing populations with different evolutionary histories and distributions, and the associated conservation strategies necessary to ensure their survival, may vary within a species. This is particularly true for marginal populations and/or those showing admixture. Here, we re-sequence genomes of 102 individuals from 21 locations for Rhododendron vialii, a threatened species distributed in the subtropical forests of southwestern China that has suffered from habitat fragmentation due to deforestation. Population structure results revealed that R. vialii can be divided into five genetic lineages using neutral single-nucleotide polymorphisms (SNPs), whereas selected SNPs divide the species into six lineages. This is due to the Guigu (GG) population, which is identified as admixed using neutral SNPs, but is assigned to a distinct genetic cluster using non-neutral loci. R. vialii has experienced multiple genetic bottlenecks, and different demographic histories have been suggested among populations. Ecological niche modeling combined with genomic offset analysis suggests that the marginal population (Northeast, NE) harboring the highest genetic diversity is likely to have the highest risk of maladaptation in the future. The marginal population therefore needs urgent ex situ conservation in areas where the influence of future climate change is predicted to be well buffered. Alternatively, the GG population may have the potential for local adaptation, and will need in situ conservation. The Puer population, which carries the heaviest genetic load, needs genetic rescue. Our findings highlight how population genomics, genomic offset analysis, and ecological niche modeling can be integrated to inform targeted conservation.

Rhododendron↗
PubMed1988

The complete nucleotide sequence of the outer coat protein, VP5, of the Australian bluetongue virus (BTV) serotype 1 reveals conserved and non-conserved sequences.

The complete sequence of the outer coat protein, VP5, of the Australian BTV serotype 1 was determined and found to be 1634 nucleotides in length. One single open reading frame of 526 amino acids was observed defining a protein of Mr 59,252 and having a charge of +0.5 at neutral pH. When compared to VP5 of BTV serotype 10 from the United States of America (US) (Purdy et al., 1986, J. Gen. Virol. 67, 957) a homology of 68% at the nucleotide level and 76% at the amino acid level, was observed. However, this conservation at the protein level was more apparent in certain regions of the gene. In four main regions the conservation varied from 83-91% while in the remaining regions the homology dropped to between 56-62%. Many of the amino acid substitutions were conservative in nature, raising the apparent overall homology to 87%. Comparisons of the hydropathy profiles of the two proteins again revealed a remarkable degree of conservation. The importance of these observations is discussed.

Amino Acid Sequence↗
PubMed1992

Nucleotide sequence of the capsid protein gene of two serotypes of San Miguel sea lion virus: identification of conserved and non-conserved amino acid sequences among calicivirus capsid proteins.

The San Miguel sea lion viruses, members of the calicivirus family, are closely related to the vesicular disease of swine viruses which can cause severe disease in swine. In order to begin the molecular characterization of these viruses, the nucleotide sequence of the capsid protein gene of two San Miguel sea lion viruses (SMSV), serotypes 1 and 4, was determined. The coding sequences for the capsid precursor protein were located within the 3' terminal 2620 bases of the genomic RNAs of both viruses. The encoded capsid precursor proteins were 79,500 and 77,634 Da for SMSV 1 and SMSV 4, respectively. The SMSV 1 protein was 47.7% and SMSV 4 was 48.6% homologous to the feline calicivirus (FCV) capsid precursor protein while the two SMSV capsid precursors were 73% homologous to each other. Six distinct regions within the capsid precursors (denoted as regions A-F) were identified based on amino acid sequence alignment analysis of the two SMSV serotypes with FCV and the rabbit hemorrhagic disease virus (RHDV) capsid protein. Three regions showed similarity among all four viruses (regions B, D and F) and one region showed a very high degree of homology between the SMSV serotypes but only limited similarity with FCV (region A). RHDV contained only a truncated region A. A fifth region, consisting of approximately 100 residues, was not conserved among any of the viruses (region E) and, in SMSV, may contain the serotype-specific determinants. Another small region (region C) contained between 15 and 27 amino acids and showed little sequence conservation. Region B showed the highest degree of conservation among the four viruses and contained the residues which had homology to the picornavirus VP3 structural protein. An open reading frame, found in the 3' terminal 514 bases of the SMSV genomes, encoded small proteins (12,575 and 12,522 Da, respectively for SMSV 1 and SMSV 4) of which 32% of the conserved amino acids were basic residues, implying a possible nucleic acid-binding function.

Amino Acid Sequence↗
PubMed1986

Conserved and non-conserved features among the yeast Ty elements.

We have isolated and characterized a Ty element from a yeast cosmid library which exhibits several unusual features: it is flanked by non-homologous delta elements and directly associated with a singular delta element. A tRNA(Glu3) gene and tRNA(Cys) gene are found in conjunction with this element, located in opposite orientation on either end of it. The sequence information now available for several Ty elements has been used in a detailed comparative analysis to determine conserved features among the Ty elements, preferably between class I elements and a class II element. Highly conserved sequence motifs appear to be located at the borders of particular segments that correspond to the putative protein domains of the Tys. Furthermore, we include a comparison of the best-conserved amino acid homologies for these putative proteins of Ty elements, transposable elements from other organisms and several retroviral proviruses to confirm their close structural resemblance.

Amino Acid Sequence↗
PubMed1988

Conserved and non-conserved regions of the outer coat protein, VP2, of the Australian bluetongue serotype 1 virus, revealed by sequence comparison to the VP2 of North American BTV serotype 10.

The complete nucleotide sequence of the outer coat protein, VP2, of the Australian BTV serotype 1 was determined and found to be 2940 nucleotides in length. An open reading frame of 961 amino acids was found, defining a protein of 112,115 Daltons having a charge of +15 at neutral pH. This coding region was flanked by 5' and 3' non-coding regions of 17 and 37 nucleotides, respectively. When compared to VP2 of the North American BTV serotype 10 (Purdy et al., 1985, J. Virol. 55, 826-830) a homology of 52% at the nucleotide level, and 40% at the amino acid level, was observed. Significant conservation of amino acid sequence was found in eleven distinct regions; the overall hydropathy of the protein, as well as 9 of its 12 cysteine residues, was conserved. The importance of this conservation, in relation to similar observations for the other outer coat protein, VP5, is discussed.

Amino Acid Sequence↗
PubMed1992

[Conservative treatment for trauma of the spleen in adults. Comparative study of thirty-four cases of conservative treatment and sixty-one cases of splenectomy].

Between 1983 and 1990, 95 patients with abdominal injury and splenic damage underwent surgery. Conservative treatment was performed in 34 cases (group I) and splenectomy was performed in 61 cases (group II). In group I, one patient died and post-operative complications occurred in 18 patients (53%). In group II, 3 patients died (of a 0hrenic abscess for one of them), and postoperative complications occurred in 38 patients (62%). There was no significant difference between group I and group II in terms of length of hospital stay and operation time; but a greater number of red cell concentrates was required during the operation in group II. No patient of group I developed post-operative infection during the mean interval of 18 months. This experience confirms that the conservative treatment of splenic contusions does not worsen the prognosis of abdominal injuries. Medium and long term infectious complications might be prevented by the conservative treatment but it is still too early to assess the real benefit of this option.

Abdominal Injuries↗
PubMed1988

Sulfogalactolipid binding protein SLIP 1: a conserved function for a conserved protein.

We have studied the species and tissue expression of the 68kD sulfogalactolipid binding protein SLIP 1, originally detected in the male germ cells of the rat (Lingwood: Can. J. Biochem. Cell Biol., 63:1077-1085, 1985). Our results show that SLIP 1 has been highly conserved during evolution and is found in the testes of all vertebrates tested. In studies in the rat, we have found that SLIP 1 is, however, tissue restricted, being found only in the brain (also a major site of sulfogalactolipid biosynthesis) in addition to the testis. SLIP 1 was also detected in mammalian oocytes. The SLIP 1 species detected in brain and oocytes retain the sulfogalactolipid-binding characteristics of rat testicular SLIP 1, indicating that, in addition to immunological features, the glycolipid-binding function of SLIP 1 is conserved in these tissues.

Animals↗
PubMed1986

Functional, developmentally expressed genes for mouse U1a and U1b snRNAs contain both conserved and non-conserved transcription signals.

Four genes that encode mouse U1a1, U1b2 and U1b6 snRNAs have been isolated from a mouse genomic DNA library. They all appear to be functional U1 genes since they are accurately transcribed into full length, capped snRNAs upon injection into Xenopus oocytes. A mouse pseudogene that is not transcribed in Xenopus oocytes was also isolated from the mouse genomic library. DNA sequence analysis of the 5' and 3' flanking regions of the functional genes revealed the presence of three highly conserved sequence elements that have been shown to be required for transcription initiation or 3' end formation in other U1 genes. Each of these U1 RNA genes also contains non-conserved sequences in the 5' flanking region that could function in their controlled expression during development.

Animals↗
PubMed1988

The preference of the mitochondrial endonuclease for a conserved sequence block in mitochondrial DNA is highly conserved during mammalian evolution.

Endonuclease activity identified in crude preparations of rat and human heart mitochondria has each been partially purified and characterized. Both the rat and human activities purify as a single enzyme that closely resembles the endonuclease of bovine-heart mitochondria (Cummings, O.W. et. al. (1987) J. Biol. Chem. 262:2005-2015). All three enzymes, for example elute similarly during gel filtration and DNA-cellulose chromatography, and exhibit similar enzymatic properties. Although the nucleotide sequences of the mtDNAs indicate that there has occurred an unusual degree of divergence in the displacement-loop region during mammalian evolution, the nucleotide specificities of the mt endonucleases appear highly conserved and show a striking preference for an evolutionarily-conserved sequence tract that is located upstream from the heavy (H)-strand origin of DNA replication (OriH).

Animals↗
PubMed1991

Mapping of the gene for a major penicillin-binding protein to a genetically conserved region of the Bacillus subtilis chromosome and conservation of the protein among related species of Bacillus.

Penicillin-binding protein 5 is the most abundant penicillin-binding protein in the vegetative membranes of Bacillus subtilis and accounts for 95% of the D,D-carboxypeptidase activity of the cell. The structural gene for penicillin-binding protein 5 was mapped to a genetically conserved region near guaB at 0 degrees on the B. subtilis chromosome, and immunoassays revealed that there is conservation of this major penicillin-binding protein among related species.

Bacillus↗
PubMed1987

Oxygen conservation and oxygen-conserving devices in chronic lung disease. A review.

The efficacy of long-term oxygen therapy for hypoxemic COPD patients is well established. However, oxygen is expensive and the portability of home oxygen is limited by the weight and bulk of the oxygen source. As a result, there has been a recent surge of interest in creating oxygen-conserving devices and methods. The efficiency of oxygen therapy can be improved over steady flow delivery by focusing oxygen delivery to early inspiration. Three methods for improving oxygen delivery efficiency--transtracheal catheter, reservoir cannula and demand-pulse oxygen delivery--are currently available for patient use. Each has its own set of advantages and disadvantages. By using oxygen conservation methods, the oxygen required to achieve adequate blood oxygenation can be reduced by a factor of 2:1 to 7:1 compared to steady flow. Thus, the cost of oxygen can be substantially reduced while increasing the portability and range of home oxygen therapy.

Costs and Cost Analysis↗
PubMed1986

Cytochrome b-559 genes from Oenothera hookeri and Nicotiana tabacum show a remarkably high degree of conservation as compared to spinach. The enigma of cytochrome b-559: highly conserved genes and proteins but no known function.

Recent data suggest that cytochrome b-559, an intrinsic membrane protein of the oxygen-evolving photosystem II in chloroplasts, is a heme cross-linked heteromeric polypeptide unit (Herrmann et al. 1984, FEBS Lett 176:239-244). The genes for this cytochrome, designated psbE and psbF, have been located on the chloroplast chromosome of Oenothera hookeri and Nicotiana tabacum by hybridization with fragments of the corresponding spinach genes, and characterized. In both cases, the nucleotide sequence discloses 2 uninterrupted reading frames of 83 and 39 codons separated by a few nucleotides, as in spinach. The amber translation stop codon of psbE overlaps the putative ribosome-binding site for psbF in all cases. The predicted molecular weights of the proteins are 9.2 and 4.3 kd, respectively. In each of the three plant species, and the direction of transcription is opposite to that of the gene for cytochrome f which is located distal to the b-559 genes. Comparison of the deduced amino acid sequences with those from the corresponding spinach genes shows 97% homology. The ubiquitous presence and remarkably high degree of structural and functional conservation of this gene cluster supports the hypothesis of a heteromeric assembly and an important functional role for cytochrome b-559.

Amino Acid Sequence↗
PubMed1986

Conservation among the immunoglobulins of carcharhine sharks and phylogenetic conservation of variable region determinants.

To study primitive vertebrate recognition molecules we have purified the immunoglobulins of three species of carcharhine sharks. The tiger (Galeocerdo cuvieri), the sandbar (Carcharhinus plumbeus) and the galapagos sharks (Carcharhinus galapagensis) possess 18S high molecular weight and 7S low molecular weight immunoglobulin forms. Both within and between species these forms closely resemble each other in polypeptide chain composition, heavy chain mass, carbohydrate content, amino acid composition, antigenic character and amino terminal sequence. These carcharhine species are separated by at least 30 million years of evolutionary time and it is remarkable that so little diversification of immunoglobulin structure has occurred during their evolution. By several criteria carcharhine immunoglobulins most closely resemble mammalian IgM. Studies of serological cross-reactions indicate that some immunoglobulin determinants have been conserved over a broad phylogenetic range of vertebrate classes; most notably JH and VHa-related markers are shared between forms as diverse as sharks and mammals.

Amino Acids↗
PubMed1989

Definition of mouse chromosome 1 and 3 gene linkage groups that are conserved on human chromosome 1: evidence that a conserved linkage group spans the centromere of human chromosome 1.

Comparative mapping between the human and the mouse genomes allows characterization of linkage groups that have been conserved over evolution. In this study, genes previously localized to adjacent regions of human chromosome 1 were mapped to discrete regions on distal mouse chromosomes 1 and 3 using an interspecific cross. Linkage analysis in mouse defined two groups in which the gene order appears to be the same as that in humans: 15 genes localized between human chromosome 1q21 and 1q32 were found to span 29.5 cM on distal mouse chromosome 1; 6 genes localized between human chromosome 1q21 and 1p22 spanned 15.6 cM on distal mouse chromosome 3. These data suggest that gene order within large chromosome segments may remain stable over long periods of evolution and that the position of the centromere may reflect a late event in the evolution of higher eukaryotic organisms. These studies provide a model for examination of specific evolutionary events.

Animals↗