Abstract:
:Animals are typically colonized by diverse bacterial symbionts, many of which are commensal and, in numerous cases, even essential for their host's proper development and growth. In exchange, the host must supply a sufficient array and quantity of nutrients to support the proliferation and persistence of its microbial community. In this investigation, we have examined such a nutritional environment by determining the symbiotic competence of auxotrophic mutants of the bioluminescent bacterium Vibrio fischeri, and have demonstrated that the host squid Euprymna scolopes provides at least 9 aa to the growing culture of symbiotic V. fischeri present in its light-emitting organ. We also collected and analyzed the extracellular fluid from this organ, in which the symbionts reside, and confirmed that it contained significant amounts of amino acids. The combined results suggested that host-derived free amino acids, as well as peptides or proteins, are a source of the amino acids that support the growth of the symbionts. This work describes a technique to sample the symbionts and their surrounding environment without contamination by host tissue components and, in combination with molecular genetic studies, allows the characterization of the nutritional conditions that support a cooperative animal-bacterial symbiosis.
journal_name
Proc Natl Acad Sci U S Aauthors
Graf J,Ruby EGdoi
10.1073/pnas.95.4.1818subject
Has Abstractpub_date
1998-02-17 00:00:00pages
1818-22issue
4eissn
0027-8424issn
1091-6490journal_volume
95pub_type
杂志文章abstract::The auditory cortex is critical for perceiving a sound's location. However, there is no topographic representation of acoustic space, and individual auditory cortical neurons are often broadly tuned to stimulus location. It thus remains unclear how acoustic space is represented in the mammalian cerebral cortex and how...
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.0901023106
更新日期:2009-04-07 00:00:00
abstract::Olfactory neuroblastoma (ONB) is a malignant tumor of the nasal mucosa whose histogenesis is unclear. A relationship to neuroblastoma (NB), a pediatric tumor of the sympathetic nervous system, is based on morphologic similarities and the expression of similar neural antigens. However, the clinical presentation of ONB ...
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.93.3.1038
更新日期:1996-02-06 00:00:00
abstract::A predictive coarse-grained protein force field [associative memory, water-mediated, structure, and energy model for molecular dynamics (AWSEM)-MD] is used to study the energy landscapes and relative stabilities of amyloid-β protein (1-40) in the monomer and all of its oligomeric forms up to an octamer. We find that a...
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.1612362113
更新日期:2016-10-18 00:00:00
abstract::A decade ago it was discovered that mature birds are able to regenerate hair cells, the receptors for auditory perception. This surprising finding generated hope in the field of auditory neuroscience that new hair cells someday may be coaxed to form in another class of warm-blooded vertebrates, mammals. We have made 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.97.22.11714
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abstract::Studies in rodents and nonhuman primates have linked the activity of N-methyl-D-aspartate (NMDA) receptors within the hippocampus to animals' performance on memory-related tasks. However, whether these receptors are similarly essential for human memory is still an open question. Here we present evidence suggesting tha...
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.96.21.12085
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::Inflammation is a major factor in heart disease. IκB kinase (IKK) and its downstream target NF-κB are regulators of inflammation and are activated in cardiac disorders, but their precise contributions and targets are unclear. We analyzed IKK/NF-κB function in the heart by a gain-of-function approach, generating an ind...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2012-07-17 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1415025111
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1980-07-01 00:00:00
abstract::In this model gravitation results from the emission and absorption of quanta (gravitons) that are scattered a few times in crossing a typical galaxy. Many features of the universe can be explained in terms of this model, although theoretical justification for the scattering of gravitons is lacking. Gravitons follow a ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2015-08-18 00:00:00
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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.1616171114
更新日期:2017-03-28 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-06-17 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2010-02-23 00:00:00
abstract::Measurements of auditory sensitivity in terms of the cochlear potentials were made in young specimens of three species of crocodilians, Caiman crocodilus and Alligator mississipiensis of the subfamily Alligatorinae and Crocodylus acutus of the subfamily Crocodylinae. These species show considerable similarity in their...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::The NMR structures of three single-amino acid variants of the C-terminal domain of the human prion protein, hPrP(121-230), are presented. In hPrP(M166V) and hPrP(R220K) the substitution is with the corresponding residue in murine PrP, and in hPrP(S170N) it is with the corresponding Syrian hamster residue. All three su...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2000-07-18 00:00:00