Strong homology theories

1987 ◽  
pp. 3-29 ◽  
Author(s):  
Friedrich W. Bauer
Keyword(s):  
Strong Homology

scholarly journals Simultaneously vanishing higher derived limits

2021 ◽  
Vol 9 ◽  
Author(s):  
Jeffrey Bergfalk ◽  
Chris Lambie-Hanson
Keyword(s):  
Euclidean Space ◽  
Metric Spaces ◽  
Inverse System ◽  
Finite Support ◽  
Partial Functions ◽  
Weakly Compact ◽  
Compact Cardinal ◽  
Strong Homology ◽  
Finite Support Iteration ◽  
Weakly Compact Cardinal

Abstract In 1988, Sibe Mardešić and Andrei Prasolov isolated an inverse system $\textbf {A}$ with the property that the additivity of strong homology on any class of spaces which includes the closed subsets of Euclidean space would entail that $\lim ^n\textbf {A}$ (the nth derived limit of $\textbf {A}$ ) vanishes for every $n>0$ . Since that time, the question of whether it is consistent with the $\mathsf {ZFC}$ axioms that $\lim ^n \textbf {A}=0$ for every $n>0$ has remained open. It remains possible as well that this condition in fact implies that strong homology is additive on the category of metric spaces. We show that assuming the existence of a weakly compact cardinal, it is indeed consistent with the $\mathsf {ZFC}$ axioms that $\lim ^n \textbf {A}=0$ for all $n>0$ . We show this via a finite-support iteration of Hechler forcings which is of weakly compact length. More precisely, we show that in any forcing extension by this iteration, a condition equivalent to $\lim ^n\textbf {A}=0$ will hold for each $n>0$ . This condition is of interest in its own right; namely, it is the triviality of every coherent n-dimensional family of certain specified sorts of partial functions $\mathbb {N}^2\to \mathbb {Z}$ which are indexed in turn by n-tuples of functions $f:\mathbb {N}\to \mathbb {N}$ . The triviality and coherence in question here generalise the classical and well-studied case of $n=1$ .

scholarly journals Ribosomal protein L30 is dispensable in the yeast Saccharomyces cerevisiae.

1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243 ◽  
Author(s):  
D M Baronas-Lowell ◽  
J R Warner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Wild Type ◽  
Diploid Strain ◽  
Chain Reaction ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ribosomal Subunits ◽  
Strong Homology ◽  
Polymerase Chain

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.

Ribosomal protein L30 is dispensable in the yeast Saccharomyces cerevisiae

1990 ◽  
Vol 10 (10) ◽  
pp. 5235-5243
Author(s):  
D M Baronas-Lowell ◽  
J R Warner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Wild Type ◽  
Diploid Strain ◽  
Chain Reaction ◽  
Yeast Saccharomyces Cerevisiae ◽  
Ribosomal Subunits ◽  
Strong Homology ◽  
Polymerase Chain

In the yeast Saccharomyces cerevisiae, L30 is one of many ribosomal proteins that is encoded by two functional genes. We have cloned and sequenced RPL30B, which shows strong homology to RPL30A. Use of mRNA as a template for a polymerase chain reaction demonstrated that RPL30B contains an intron in its 5' untranslated region. This intron has an unusual 5' splice site, C/GUAUGU. The genomic copies of RPL30A and RPL30B were disrupted by homologous recombination. Growth rates, primer extension, and two-dimensional ribosomal protein analyses of these disruption mutants suggested that RPL30A is responsible for the majority of L30 production. Surprisingly, meiosis of a diploid strain carrying one disrupted RPL30A and one disrupted RPL30B yielded four viable spores. Ribosomes from haploid cells carrying both disrupted genes had no detectable L30, yet such cells grew with a doubling time only 30% longer than that of wild-type cells. Furthermore, depletion of L30 did not alter the ratio of 60S to 40S ribosomal subunits, suggesting that there is no serious effect on the assembly of 60S subunits. Polysome profiles, however, suggest that the absence of L30 leads to the formation of stalled translation initiation complexes.

Novel conserved elements upstream of theH19gene are transcribed and act as mesodermal enhancers

Development ◽  
2002 ◽  
Vol 129 (5) ◽  
pp. 1205-1213
Author(s):  
Robert A. Drewell ◽  
Katharine L. Arney ◽  
Takahiro Arima ◽  
Sheila C. Barton ◽  
James D. Brenton ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Pattern ◽  
Reporter Gene ◽  
Differentially Methylated Region ◽  
Genomic Sequencing ◽  
Strong Homology ◽  
Imprinting Control Region ◽  
Enhancer Function ◽  
Human And Mouse ◽  
Mouse Genomic

The reciprocally imprinted H19 and Igf2 genes form a co-ordinately regulated 130 kb unit in the mouse controlled by widely dispersed enhancers, epigenetically modified silencers and an imprinting control region (ICR). Comparative human and mouse genomic sequencing between H19 and Igf2 revealed two novel regions of strong homology upstream of the ICR termed H19 upstream conserved regions (HUCs). Mouse HUC1 and HUC2 act as potent enhancers capable of driving expression of an H19 reporter gene in a range of mesodermal tissues. Intriguingly, the HUC sequences are also transcribed bi-allelically in mouse and human, but their expression pattern in neural and endodermal tissues in day 13.5 embryos is distinct from their enhancer function. The location of the HUC mesodermal enhancers upstream of the ICR and H19, and their capacity for interaction with both H19 and Igf2 requires critical re-evaluation of the cis-regulation of imprinted gene expression of H19 and Igf2 in a range of mesodermal tissues. We propose that these novel sequences interact with the ICR at H19 and the epigenetically regulated silencer at differentially methylated region 1 (DMR1) of Igf2.

Primary structure of a human mitochondrial protein homologous to the bacterial and plant chaperonins and to the 65-kilodalton mycobacterial antigen

1989 ◽  
Vol 9 (5) ◽  
pp. 2279-2283
Author(s):  
S Jindal ◽  
A K Dudani ◽  
B Singh ◽  
C B Harley ◽  
R S Gupta
Keyword(s):  
Mammalian Cells ◽  
Mitochondrial Protein ◽  
Protein Structures ◽  
Mycobacterial Antigen ◽  
Related Protein ◽  
Bisphosphate Carboxylase ◽  
Oligomeric Protein ◽  
Strong Homology ◽  
Major Antigen ◽  
High Degree

The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.

Strong homology on CH(pro-Top)

2000 ◽  
pp. 353-378
Author(s):  
Sibe Mardešić
Keyword(s):  
Strong Homology

Strong homology groups of systems

2000 ◽  
pp. 327-351
Author(s):  
Sibe Mardešić
Keyword(s):  
Homology Groups ◽  
Strong Homology

scholarly journals Structural and functional analyses of the N-terminal domain of the A subunit of aBacillus megateriumspore germinant receptor

2019 ◽  
Vol 116 (23) ◽  
pp. 11470-11479 ◽  
Author(s):  
Yunfeng Li ◽  
Kai Jin ◽  
Abigail Perez-Valdespino ◽  
Kyle Federkiewicz ◽  
Andrew Davis ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Abc Transporters ◽  
Spore Germination ◽  
Critical Role ◽  
Chemical Shift Perturbation ◽  
Terminal Domain ◽  
Proposed Model ◽  
Strong Homology ◽  
A Subunit ◽  
Functional Analyses

Germination ofBacillusspores is induced by the interaction of specific nutrient molecules with germinant receptors (GRs) localized in the spore’s inner membrane. GRs typically consist of three subunits referred to as A, B, and C, although functions of individual subunits are not known. Here we present the crystal structure of the N-terminal domain (NTD) of the A subunit of theBacillus megateriumGerK3GR, revealing two distinct globular subdomains bisected by a cleft, a fold with strong homology to substrate-binding proteins in bacterial ABC transporters. Molecular docking, chemical shift perturbation measurement, and mutagenesis coupled with spore germination analyses support a proposed model that the interface between the two subdomains in the NTD of GR A subunits serves as the germinant binding site and plays a critical role in spore germination. Our findings provide a conceptual framework for understanding the germinant recruitment mechanism by which GRs trigger spore germination.

scholarly journals Strong homology of inverse systems of spaces. I

1985 ◽  
Vol 19 (1) ◽  
pp. 29-43 ◽  
Author(s):  
JuriǐT. Lisica ◽  
Sibe Mardešić
Keyword(s):  
Inverse Systems ◽  
Strong Homology
Sign in / Sign up

Export Citation Format

Share Document