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PubMed1997

Site-directed spin-labeling study of the structure and subunit interactions along a conserved sequence in the alpha-crystallin domain of heat-shock protein 27. Evidence of a conserved subunit interface.

Site-directed spin-labeling (SDSL) was used to investigate the secondary structure, solvent accessibility, and tertiary and quaternary interactions along the sequence located between residues 133 and 144 in the alpha-crystallin domain of human heat-shock protein 27 (HSP 27). The sequence is conserved among mammalian sHSP and shows similarity to the region of highest homology between alpha A- and alpha B-crystallins. Eleven sequential single cysteine mutants were prepared and reacted with a sulfhydryl-specific spin-label. The accessibilities of attached nitroxide side chains to a paramagnetic probe in the aqueous solution were determined. Spectral line shapes were analyzed in terms of side-chain mobility and spatial proximity to nearby nitroxides. The sequence-specific mobilities and accessibilities varied with a period of 2, consistent with the presence of a beta-strand along the sequence. At even sites, the nitroxide environment is highly ordered with virtually no accessibility to the hydrophilic probe, indicating that one face of the strand is buried. Furthermore, spin-spin interactions between nitroxides in the oligomeric structure strongly suggest that equivalent strands from different subunits are in close spatial proximity. These structural characteristics are remarkably similar to those of the equivalent sequence in alpha A-crystallin [Berengian, A. R., Bova, M. P., and Mchaourab, H. S. (1997) Biochemistry 36, 9951-9957]. In both proteins, a beta-strand spans the sequence and is located at a subunit interface, indicating that one set of interactions between subunits, and its associated symmetry, is conserved. This is the first report of sequence-specific structural similarity between alpha A-crystallin and HSP 27 and the first identification of a conserved secondary structural element in the alpha-crystallin domain.

Amino Acid Sequence↗
PubMed2005

DG-CST (Disease Gene Conserved Sequence Tags), a database of human-mouse conserved elements associated to disease genes.

The identification and study of evolutionarily conserved genomic sequences that surround disease-related genes is a valuable tool to gain insight into the functional role of these genes and to better elucidate the pathogenetic mechanisms of disease. We created the DG-CST (Disease Gene Conserved Sequence Tags) database for the identification and detailed annotation of human-mouse conserved genomic sequences that are localized within or in the vicinity of human disease-related genes. CSTs are defined as sequences that show at least 70% identity between human and mouse over a length of at least 100 bp. The database contains CST data relative to over 1088 genes responsible for monogenetic human genetic diseases or involved in the susceptibility to multifactorial/polygenic diseases. DG-CST is accessible via the internet at http://dgcst.ceinge.unina.it/ and may be searched using both simple and complex queries. A graphic browser allows direct visualization of the CSTs and related annotations within the context of the relative gene and its transcripts.

Animals↗
PubMed1996

Roles of the conserved cytoplasmic region and non-conserved carboxy-terminal region of SecE in Escherichia coli protein translocase.

SecE, an essential membrane component of the Escherichia coli protein translocase, consists of 127 amino acid residues. Only a part of the second putative cytoplasmic region comprising some 13 residues is essential for the SecE function as long as the proper topological arrangement is retained. The Trp84 and Pro85 residues of this region are conserved in all eubacterial SecE homologues. The conservation of positively charged residues corresponding to Arg80 and Lys81 is also substantial. We deleted or replaced these residues to assess their roles in the SecE function. Deletion of the Arg80-Lys81 dipeptide did not abolish the SecE function whereas that of Trp84 or Pro85 caused a loss of the function. Strikingly, however, replacement of Pro85 with either Gly, Ser, or Ala, and that of Trp84 with Lys did not abolish the SecE function. These results indicate that the strong conservation of these residues does not reflect their obligatory requirement for the SecE function. A chimeric SecE possessing the cytoplasmic region of the E. coli SecE and the following region of the Bacillus subtilis SecE was able to form the translocation machinery together with SecA, SecY, and SecG. Although a Leu to Arg mutation at position 108 has been thought to cause a loss of signal recognition fidelity and thereby suppress a signal sequence defect, the same mutation at position 111 caused a complete loss of the function. The levels of SecY and SecG in the secEcsE501 mutant, which expresses SecE at a decreased level and is sensitive to low temperature, increased upon the expression of functional SecE derivatives, irrespective of the site of mutation, suggesting that the levels of SecY and SecG are co-operatively determined by the level of functional, but not non-functional, SecE. Based on these results, the SecE function in the translocase is discussed.

Adenosine Triphosphatases↗
PubMed2005

Conservation genomics: applying whole genome studies to species conservation efforts.

Studies of complete genomes are leading to a new understanding of the biology of mammals and providing ongoing insights into the fundamental aspects of the organization and evolution of biological systems. Comparison of primate genomes can identify aspects of their organization, regulation and function that appeared during the primate radiation, but without comparison to more evolutionarily distant mammals and other vertebrates, highly conserved aspects of genome architecture will not be accurately identified nor will the lineage-specific changes be identified as such. Many species of primates face risks of extinction; yet the knowledge of their genomes will provide a deeper understanding of primate adaptations, human origins, and provide the framework for discoveries anticipated to improve human medicine. The great apes, the closest relatives of the human species, are among the most vulnerable and most important for human medical studies. However, apes are not the only species whose genomic information will enrich humankind. Comparative genomic studies of endangered species can benefit conservation efforts on their behalf. Increased knowledge of genome makeup and variation in endangered species finds conservation application in population evaluation monitoring and management, understanding phylozoogeography, can enhance wildlife health management, identify risk factors for genetic disorders, and provide insights into demographic management of small populations in the wild and in captivity.

Animals↗
PubMed2006

A global definition of expression context is conserved between orthologs, but does not correlate with sequence conservation.

BACKGROUND: The massive scale of microarray derived gene expression data allows for a global view of cellular function. Thus far, comparative studies of gene expression between species have been based on the level of expression of the gene across corresponding tissues, or on the co-expression of the gene with another gene. RESULTS: To compare gene expression between distant species on a global scale, we introduce the "expression context". The expression context of a gene is based on the co-expression with all other genes that have unambiguous counterparts in both genomes. Employing this new measure, we show 1) that the expression context is largely conserved between orthologs, and 2) that sequence identity shows little correlation with expression context conservation after gene duplication and speciation. CONCLUSION: This means that the degree of sequence identity has a limited predictive quality for differential expression context conservation between orthologs, and thus presumably also for other facets of gene function.

Animals↗
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↗
PubMed1997

The conserved N-capping box in the hydrophobic core of glutathione S-transferase P1-1 is essential for refolding. Identification of a buried and conserved hydrogen bond important for protein stability.

The second domain of cytosolic glutathione S-transferases (GSTs) contains a strictly conserved N-capping box motif (Ser/Thr-Xaa-Xaa-Asp) at the beginning of alpha6-helix in the hydrophobic core of the molecule. Considering the specific function attributed to capping box residues in the helix nucleation, we decided to investigate, by site-directed mutagenesis, the role that this motif could have in the folding and stability of human GSTP1-1. Both capping box mutants, S150A and D153A, were significantly more thermolabile than wild-type GSTP1-1, indicating that the local destabilization of the alpha6-helix determined by a single capping residue mutation affects the overall stability of the protein. The results also show that, in addition to capping interactions, an important role in the stability of the final structure of the protein is played by a buried and conserved hydrogen bond formed between the side chain of Asp-153 and the amide NH of Ile-144 located in the long loop preceding alpha6-helix. Reactivation experiments in vitro indicate that the N-capping box is essential for refolding of the denatured protein at a physiological temperature. The results suggest that during folding this buried and conserved motif, making a definite set of native-like contacts, determines the formation of a specific folding nucleus that probably represents a transition state of the folding process.

Circular Dichroism↗
PubMed2001

Primary gastrointestinal non-Hodgkin's lymphoma: II. Combined surgical and conservative or conservative management only in localized gastric lymphoma--results of the prospective German Multicenter Study GIT NHL 01/92.

PURPOSE: The aim of the study was to obtain data on anatomic and histologic distribution, clinical features, and treatment results of patients with primary gastrointestinal non-Hodgkin's lymphomas, particularly combined surgical and conservative treatment (CSCT) versus conservative treatment (CT) alone for primary gastric lymphoma (PGL) in localized stages. PATIENTS AND METHODS: Whether the treatment included surgery was left to the discretion of each participating center. Radiotherapy (Rx) and chemotherapy were stratified according to histologic grading, stage, and the inclusion or omission of surgery as follows: patients with low-grade PGL were treated with extended-field (EF) Rx (30 Gy). In case of residual tumor after surgery or in case of CT only (in stage IIE after six cycles of cyclophosphamide, vincristine, and prednisone), an additional boost of 10 Gy was given. All patients with high-grade PGL were treated with four (stage IE) or six (stage IIE) cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone followed by EF Rx (stage IE) or involved-field (IF) Rx (stage IIE). Rx dosage corresponded to low-grade NHL. RESULTS: Between October 1992 and November 1996, 106 patients had CT only. The survival rate (SR) after 5 years was 84.4% and was influenced neither by patients' characteristics nor by stage or histologic grade. Seventy-nine patients had CSCT. Their SR was 82.0%. Complete resection of the tumor (R0) was prognostic for the overall survival (P =.0165) as compared with incomplete resection. CONCLUSION: Although the study was not randomized, a stomach-conserving approach may be favored.

Aged↗
PubMedDate not supplied

[Conservative... and non conservative... treatment of renal blunt injuries].

Whether patients with blunt renal trauma should be managed conservatively without surgery or undergo surgery is often hard to decide. We describe three clinical cases of blunt renal trauma, all involving the left kidney. All three patients had abdominal ultrasound studies and computerized tomographic (CT) scans. In the first case, an accidental fall led to severe injury of the renal hilus causing massive retroperitoneal extravasation. The patient underwent emergency nephrectomy and survived. The second case concerned a patient who was involved in a road accident, suffered injuries mainly affecting the spleen, and underwent splenectomy. A postoperative CT scan showed left renal vein thrombosis functionally excluding the inferior pole of the kidney. The patient received conservative non surgical treatment. A follow-up imaging study showed that although the thrombosis had resolved the renal pole had failed to regain normal function. In the third case, mild apparently unimportant trauma led to a massive hemorrhage responsible for a severe shock state. Despite prompt nephrectomy, renal failure and and pulmonary complications developed and one month after the injuries the patient died. The medical history referred to a "chronic hematoma" secondary to a childhood injury. In this case, the pre-existing hematoma probably led to a permanent communication with the vascular and excretory tree thus resulting in a kind of "silent" fistula that the relatively mild injury unexpectedly disrupted. For the two left nephrectomies we used a midline approach after isolating the renal Treitz vessels; special care was taken to mobilize the left colon. Although blunt renal trauma often responds to non surgical conservative treatment, some patients should undergo prompt surgery. All patients must be scheduled for long-term clinical and imaging follow-up.

Adult↗
PubMedDate not supplied

[Conservative treatment of ectopic pregnancy in a 27 years old patient with stage-Ia ovarian cancer after conservative surgical treatment and chemotherapy].

We report a case of conservative treatment of ectopic pregnancy in a 27 years old patient, previously treated for ovarian cancer. Two years before she had surgery because of tumour in the left ovary. Ovarian cancer in stage la according to FIGO was confirmed. Considering the patient s young age, future reproductive plans and the early stage of cancer, the patient qualified for conservative treatment. Left adnexectomy with consequent chemotherapy (6 courses) was performed. Two years later on the ground of clinical symptoms, gynaecologic examination, sonography and changes in HCG serum concentration, ectopic pregnancy was recognised in the right tube. We applied conservative management with intramuscularly administrated Methotrexate. The patient, in good condition, was discharged from hospital on day 12 after injection of Methotrexate.

Abortifacient Agents, Nonsteroidal↗
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↗
PubMed1996

Guidelines on the audiologist's role in occupational and environmental hearing conservation. Ad Hoc Committee on Occupational and Environmental Hearing Conservation.

This position statement is a policy of the American Speech-Language-Hearing Association (ASHA). The document was developed by the Ad Hoc Committee on Occupational and Environmental Hearing Conservation and adopted by the American Speech-Language-Hearing Association (ASHA) Legislative Council in December 1995. Members of the Ad Hoc Committee on Occupational and Environmental Hearing Conservation include Derek Dunn, Rena H. Glaser, Theresa Schulz (chair), Andrew Stewart, Maureen E. Thompson (ex officio), and Vickie Tuten. Lawrence Higdon, ASHA vice president for professional practices in audiology, served as monitoring vice president. This position statement supersedes the 1985 position statement, "The Audiologist's Role in Occupational Hearing Conservation" (LC7-84).

American Speech-Language-Hearing Association↗
PubMed2001

Site-directed mutagenesis of human nucleoside triphosphate diphosphohydrolase 3: the importance of conserved glycine residues and the identification of additional conserved protein motifs in eNTPDases.

Glycine residues are recognized as important structural determinants in nucleotide-binding domains of many enzymes. The functional significance of seven glycine residues invariant in all 22 eNTPDase sequences was therefore examined. Glycine-to-alanine mutants of eNTPDase3 were analyzed for nucleotidase activities and tertiary and quaternary structure changes. Mutations G98A and G183A had modest effects on ATPase and ADPase activities. The G141A mutation resulted in 4- to 5-fold decreased nucleotidase activity, while the G222A mutation decreased ATPase activity 20-fold, and ADPase activity 6-fold. Unlike the other five glycine mutants, the G263A and G462A mutations caused significant loss of nucleotidase activity which was observed concomitant with lower protein expression levels, large-scale changes in tertiary and quaternary protein structure, and decreased trafficking to the plasma membrane. Thus, these data identify glycine residues that are essential for enzymatic activity and the tertiary and quaternary structure of eNTPDase3. Further, two additional conserved regions in the eNTPDases are identified, apyrase conserved regions ACR1a and ACR4a, which may be involved in phosphate binding/hydrolysis and protein folding, respectively.

Adenosine Triphosphatases↗
PubMed2001

Targeting sites for conservation: using a patch-based ranking scheme to assess conservation potential.

Rare habitats are increasingly threatened by fragmentation and measures are required to conserve these valuable resources. Here, we present a method of targeting habitat patches for conservation using a Geographical Information System. We ranked patches of chalk grassland in the Chiltern Hills Area of Outstanding Natural Beauty using simple abiotic criteria, namely: patch area, patch shape, proximity to areas of the same habitat and surrounding land-use type. We compiled a regionally specific list of indicator species and ranked the habitat patches based on their alpha diversity (calculated from species richness). We compared the results of the two ranking schemes and identified key aggregations of the existing reserve network. These could form the basis of future habitat expansion as required by the United Kingdom Biodiversity Action Plan.

Animals↗
PubMed2002

The role of trade-offs in biodiversity conservation planning: linking local management, regional planning and global conservation efforts.

Biodiversity conservation planning requires trade-offs, given the realities of limited resources and the competing demands of society. If net benefits for society are important, biodiversity assessment cannot occur without other sectoral factors "on the table". In trade-offs approaches, the biodiversity value of a given area is expressed in terms of the species or other components of biodiversity that it has that are additional to the components protected elsewhere. That "marginal gain" is called the complementarity value of the area. A recent whole-country planning study for Papua New Guinea illustrates the importance of complementarity-based trade-offs in determining priority areas for biodiversity conservation, and for designing economic instruments such as biodiversity levies and offsets. Two international biodiversity programs provide important new opportunities for biodiversity trade-offs taking complementarity into account. Both the Millennium Ecosystem Assessment and the Critical Ecosystems or "hotspots" programs can benefit from an explicit framework that incorporates trade-offs, in which a balance is achieved not only by land-use allocation among areas, but also by the crediting of partial protection of biodiversity provided by sympathetic management within areas. For both international programs, our trade-offs framework can provide a natural linkage between local, regional and global planning levels.

Animals↗
PubMed2006

Both conserved and non-conserved regions of Spo11 are essential for meiotic recombination initiation in yeast.

DNA double-strand breaks (DSBs) are the initiators of most meiotic recombination events. In Saccharomyces cerevisiae, at least ten genes are necessary for meiotic DSB formation. However, the molecular roles of these proteins are not clearly understood. The meiosis-specific Spo11 protein, which shows sequence similarity with a subunit of an archaeal topoisomerase, is believed to catalyze the meiotic DSB formation. Spo11 is also required for induction of meiotic DSBs at long inverted repeats and at large trinucleotide repeat tracts. Here we report the isolation and characterization of temperature-sensitive spo11-mutant alleles to better understand how Spo11 functions, and how meiotic DSBs are generated at various recombination hotspots. Analysis of mutation sites of isolated spo11-mutant alleles indicated that both N-terminal and C-terminal non-conserved residues of Spo11 are essential for the protein's function, possibly for interaction with other meiotic DSB enzymes. Several of the mutation sites within the conserved region are predicted to lie on the surface of the protein, suggesting that this region is required for activation of the meiotic initiation complex via protein-protein interaction. In addition to the conditional mutants, we isolated partially recombination-defective mutants; analysis of one of these mutants indicated that Ski8, as observed previously, interacts with Spo11 via the latter's C-terminal residues.

Alleles↗
PubMed2003

The fully conserved Asp residue in conserved sequence region I of the alpha-amylase family is crucial for the catalytic site architecture and activity.

The alpha-amylase family is a large group of starch processing enzymes [Svensson, B. (1994) Plant Mol. Biol. 25, 141-157]. It is characterized by four short sequence motifs that contain the seven fully conserved amino acid residues in this family: two catalytic carboxylic acid residues and four substrate binding residues. The seventh conserved residue (Asp135) has no direct interactions with either substrates or products, but it is hydrogen-bonded to Arg227, which does bind the substrate in the catalytic site. Using cyclodextrin glycosyltransferase as an example, this paper provides for the first time definite biochemical and structural evidence that Asp135 is required for the proper conformation of several catalytic site residues and therefore for activity.

Aspartic Acid↗