Abstract:
:Thermotaxis by individual amoebae of Dictyostelium discoideum on a temperature gradient is described. These amoebae show positive thermotaxis at temperatures between 14 degrees C and 28 degrees C shortly (3 hr) after food depletion. Increasing time on the gradient reduces the positive thermotactic response at the lower temperature gradients (midpoint temperatures of 14, 16, and 18 degrees C), and amoebae show an apparent negative thermotactic response after 12 hr on the gradient. The thermotaxis response curve for "wild-type" amoebae after 16 hr on the gradient is similar to that shown for the pseudoplasmodia. Growth of the amoebae at a different temperature causes a shift in the thermotaxis response curve for the amoebae. This adaptation is similar to that shown for the pseudoplasmodia. Two mutants in thermotaxis, HO428 and HO813, show changes in amoebal thermotaxis similar to the observed changes in pseudoplasmodial thermotaxis. On the basis of the similarities between these responses, thermotaxis by the amoebae is proposed to be the basis for thermotaxis by the multicellular pseudoplasmodium.
journal_name
Proc Natl Acad Sci U S Aauthors
Hong CB,Fontana DR,Poff KLdoi
10.1073/pnas.80.18.5646subject
Has Abstractpub_date
1983-09-01 00:00:00pages
5646-9issue
18eissn
0027-8424issn
1091-6490journal_volume
80pub_type
杂志文章abstract::The modulation of K+ channels by serotonin (5-HT) receptors was studied by coinjecting Xenopus oocytes with mRNA transcribed in vitro from a cloned 5-HT 1C subtype (5-HT1C) receptor gene, together with size-fractionated mRNA isolated from rat cerebral cortex that expresses K+ channels. After intracellular loading with...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.6.2560
更新日期:1991-03-15 00:00:00
abstract::The pineal organ of the lizard Anolis carolinensis can be maintained for up to 10 days in superfused organ culture. During this time it synthesizes and releases melatonin into the medium flowing slowly over it. Collection of timed aliquots of medium and subsequent analysis for melatonin by radioimmunoassay reveal circ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.19.6119
更新日期:1983-10-01 00:00:00
abstract::We showed previously that rrn P1 promoters require unusually high concentrations of the initiating nucleoside triphosphates (ATP or GTP, depending on the promoter) for maximal transcription in vitro. We proposed that this requirement for high initiating NTP concentrations contributes to control of the rrn P1 promoters...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.132285199
更新日期:2002-06-25 00:00:00
abstract::Interaction of syntaxin 1 with the alpha(1D) subunit of the voltage-gated L type Ca(2+) channel was investigated in the pancreatic beta cell. Coexpression of the enhanced green fluorescent protein-linked alpha(1D) subunit with the enhanced blue fluorescent protein-linked syntaxin 1 and Western blot analysis together w...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.18.10164
更新日期:1999-08-31 00:00:00
abstract::Animals and plants use modified cell cycles to achieve particular developmental strategies. In one common example, most animals and plants have tissues in which the cells become polyploid or polytene by means of an S-G cycle, but the mechanism by which mitosis is inhibited in the endo cycle is not understood. The Dros...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.172391099
更新日期:2002-08-20 00:00:00
abstract::Drosophila neuroblasts divide asymmetrically by aligning their mitotic spindle with cortical cell polarity to generate distinct sibling cell types. Neuroblasts asymmetrically localize Galphai, Pins, and Mud proteins; Pins/Galphai direct cortical polarity, whereas Mud is required for spindle orientation. It is currentl...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0701812104
更新日期:2007-09-04 00:00:00
abstract::We report a method for introducing mtDNA mutations into the mouse female germ line by means of embryonic stem (ES) cell cybrids. Mitochondria were recovered from the brain of a NZB mouse by fusion of synaptosomes to a mtDNA-deficient (rho degrees ) cell line. These cybrids were enucleated and the cytoplasts were elect...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.250491597
更新日期:2000-12-19 00:00:00
abstract::We have determined the molecular genetic basis of congenital adrenal hyperplasia due to 21-hydroxylase (21-OHase) deficiency. This common disorder of cortisol biosynthesis is HLA-linked. The haplotype HLA-(A3);Bw47;DR7 is strongly associated with 21-OHase deficiency and always carries a null allele at the locus encodi...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.23.7505
更新日期:1984-12-01 00:00:00
abstract::Addition of antisense oligonucleotides to cell cultures has been used to specifically inhibit gene expression. We have investigated the mechanism by which oligonucleotides enter living cells. These compounds are taken up by cells in a saturable, size-dependent manner compatible with receptor-mediated endocytosis. Poly...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.10.3474
更新日期:1989-05-01 00:00:00
abstract::Global supply chains play a critical role in many of the most pressing environmental stresses and social struggles identified by the United Nations' Sustainable Development Goals (SDGs). Responding to calls from the global community, companies are adopting a variety of voluntary practices to improve the environmental ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1716695115
更新日期:2018-02-27 00:00:00
abstract::Recent evidence indicates there is a role for small membrane vesicles, including exosomes, as vehicles for intercellular communication. Exosomes secreted by most cell types can mediate transfer of proteins, mRNAs, and microRNAs, but their role in the transmission of infectious agents is less established. Recent studie...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1221899110
更新日期:2013-08-06 00:00:00
abstract::One of the morphological hallmarks of terminally differentiated secretory cells is highly proliferated membrane of the rough endoplasmic reticulum (ER), but the molecular basis for the high rate of protein biosynthesis in these cells remains poorly documented. An important aspect of ER translational control is the mol...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1901742116
更新日期:2019-05-07 00:00:00
abstract::The conversion of cells from a normal phenotype to full malignancy apparently requires multiple genetic events. Efforts to reconstruct multistep tumorigenesis in cell culture have shown that two types of oncogenes (typified by HRAS and MYC) can cooperate to elicit complete transformation. Transformation of embryonic r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.12.4355
更新日期:1988-06-01 00:00:00
abstract::Two features make the tooth an excellent model in the study of evolutionary innovations: the relative simplicity of its structure and the fact that the major tooth-forming genes have been identified in eutherian mammals. To understand the nature of the innovation at the molecular level, it is necessary to identify the...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.22.13056
更新日期:1998-10-27 00:00:00
abstract::The shape of a plant is largely determined by regulation of lateral branching. Branching architecture can vary widely in response to both genotype and environment, suggesting regulation by a complex interaction of autonomous genetic factors and external signals. Tillers, branches initiated at the base of grass plants,...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1102819108
更新日期:2011-08-16 00:00:00
abstract::Several 400- to 800-kb murine chromosome domains switch from early to late replication during loss of pluripotency, accompanied by a stable form of gene silencing that is resistant to reprogramming. We found that, whereas enhanced nuclease accessibility correlated with early replication genome-wide, domains that switc...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1207185109
更新日期:2012-07-31 00:00:00
abstract::Caenorhabditis elegans sqv mutants are defective in vulval epithelial invagination and have a severe reduction in hermaphrodite fertility. The gene sqv-7 encodes a multitransmembrane hydrophobic protein resembling nucleotide sugar transporters of the Golgi membrane. A Golgi vesicle enriched fraction of Saccharomyces c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.061593098
更新日期:2001-03-27 00:00:00
abstract::Initiation and control of replication of the broad-host-range plasmid RK2 requires two plasmid-encoded elements, the replication origin (oriV) and the initiation protein TrfA. Purified TrfA is largely in the form of a dimer; however, only the monomeric form of the protein can bind specifically to the direct repeats (i...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.26.14378
更新日期:1997-12-23 00:00:00
abstract::Biomass burning drives changes in greenhouse gases, climate-forcing aerosols, and global atmospheric chemistry. There is controversy about the magnitude and timing of changes in biomass burning emissions on millennial time scales from preindustrial to present and about the relative importance of climate change and hum...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1807172115
更新日期:2018-12-04 00:00:00
abstract::In humans, septal defects are among the most prevalent congenital heart diseases, but their cellular and molecular origins are not fully understood. We report that transcription factor Tbx5 is present in a subpopulation of endocardial cells and that its deletion therein results in fully penetrant, dose-dependent atria...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0914888107
更新日期:2010-11-09 00:00:00
abstract::Overexpression of ErbB-2/Neu has been causally associated with mammary epithelial transformation. Here we report that blockade of the epidermal growth factor receptor (EGFR) kinase with AG-1478 markedly delays breast tumor formation in mouse mammary tumor virus (MMTV)/Neu + MMTV/transforming growth factor alpha bigeni...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.160564197
更新日期:2000-08-15 00:00:00
abstract::The results of previous preclinical and clinical studies have identified angiogenin (ANG) as a potentially important target for anticancer therapy. Here we report the design and implementation of a high-throughput screening assay to identify small molecules that bind to the ribonucleolytic active site of ANG, which is...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.152342999
更新日期:2002-07-23 00:00:00
abstract::We report 10 heterozygous mutations in the human insulin gene in 16 probands with neonatal diabetes. A combination of linkage and a candidate gene approach in a family with four diabetic members led to the identification of the initial INS gene mutation. The mutations are inherited in an autosomal dominant manner in t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0707291104
更新日期:2007-09-18 00:00:00
abstract::The coelacanth fish Latimeria chalumnae is the sole surviving species of a phylogenetic lineage that was founded more than 400 million years ago and that has changed morphologically very little since that time. Little is known about the molecular evolution of this "living fossil," considered by some taxonomists to be ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.23.11065
更新日期:1994-11-08 00:00:00
abstract::Like protein enzymes, RNA enzymes (ribozymes) provide specific binding sites for their substrates. We now show that equilibrium dissociation constants for complexes between the Tetrahymena ribozyme and its RNA substrates and products can be directly measured by electrophoresis in polyacrylamide gels containing divalen...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.21.8187
更新日期:1990-11-01 00:00:00
abstract::We show that supercoiling of a DNA trefoil, the simplest knotted ring, perturbs differently the spatial writhe of its two chiral forms. As a consequence, the negative-noded and positive-noded DNA trefoils can be resolved by gel electrophoresis. Analysis of the chirality of trefoils produced by cyclization of two linea...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.94.5.1692
更新日期:1997-03-04 00:00:00
abstract::The 93-residue transmembrane protein CrgA in Mycobacterium tuberculosis is a central component of the divisome, a large macromolecular machine responsible for cell division. Through interactions with multiple other components including FtsZ, FtsQ, FtsI (PBPB), PBPA, and CwsA, CrgA facilitates the recruitment of the pr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1415908112
更新日期:2015-01-13 00:00:00
abstract::A modified differential screening procedure was applied to analyze cDNA libraries of cloned helper T lymphocytes (Th) and cytolytic T lymphocytes (CTL). Negative and positive differential screening and RNA blot analysis were used to identify cDNA clones that were expressed preferentially in Th or CTL. Seven clones cor...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.9.2896
更新日期:1987-05-01 00:00:00
abstract::Human mammary epithelial cells secrete and express on their cell surfaces complex mucin glycoproteins (Mr greater than 250,000) that are developmentally regulated, tumor-associated, and highly immunogenic. Studies using monoclonal antibodies directed to these glycoproteins suggest that their molecular structures can v...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.17.6060
更新日期:1987-09-01 00:00:00
abstract::A major challenge in interpreting genome sequences is understanding how the genome encodes the information that specifies when and where a gene will be expressed. The first step in this process is the identification of regions of the genome that contain regulatory information. In higher eukaryotes, this cis-regulatory...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.231608898
更新日期:2002-01-22 00:00:00