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  • Key words Fluorescence in situ hybridization  (1)
  • Lake Pontchartrain  (1)
  • MIS 5  (1)
  • Maize  (1)
  • 1
    Publication Date: 2023-12-14
    Description: 〈title xmlns:mml="http://www.w3.org/1998/Math/MathML"〉Abstract〈/title〉〈p xmlns:mml="http://www.w3.org/1998/Math/MathML" xml:lang="en"〉The reconstruction of accurate sea‐surface temperatures (SST) is of utmost importance due to the ocean's central role in the global climate system. Yet, a number of environmental processes might bias reliable SST estimations. Here, we investigate the fidelity of SST reconstructions for the western tropical South Atlantic (WTSA) for the interval covered by Marine Isotope Stages (MIS) 6–5, utilizing a core collected off eastern Brazil at ∼20°S. This interval was selected as previous SST estimates based on Mg/Ca ratios of planktic foraminifera suggested a peculiar pooling of warm surface waters in the WTSA during MIS 6 despite glacial boundary conditions. To ground‐truth the Mg/Ca‐based SST data we generated SST reconstructions on the same core material using the alkenone and TEX〈sub〉86〈/sub〉 paleothermometers. Comparison with alkenone‐based temperature estimates corroborate the previous Mg/Ca‐based SST reconstructions, supporting the suggestion of a warm‐water anomaly during MIS 6. In contrast, TEX〈sub〉86〈/sub〉‐derived temperatures, albeit representing annual mean SST in recent core top samples, are up to 6°C colder than Mg/Ca‐ and alkenone‐based SST reconstructions. We interpret the periods of anomalously cold TEX〈sub〉86〈/sub〉‐temperatures as a result of a vertical migration of the TEX〈sub〉86〈/sub〉 producers (heterotrophic marine Thaumarchaeota) toward greater water depths, following food availability during phases of enhanced fluvial suspension input. Likewise, the data suggest that alkenone‐based SST are, albeit to a minor degree when compared to TEX〈sub〉86〈/sub〉, affected by river run‐off and/or a seasonal bias in the growth season of haptophyte algae.〈/p〉
    Description: Plain Language Summary: In this study, we investigate the accuracy of sea‐surface temperature (SST) reconstructions for the western tropical South Atlantic (WTSA) for the interval covered by Marine Isotope Stages (MIS) 6–5—the penultimate glacial‐interglacial cycle (ca. 190,000 to 70,00 years before present). This time interval was selected because previous SST estimates based on Mg/Ca ratios of planktic foraminifera suggested a pooling of warm surface waters in the WTSA during late MIS 6 despite the cold glacial conditions. To verify the Mg/Ca‐based SST data, we generated temperature reconstructions from a core located off Eastern Brazil using two common paleothermometers that based on lipid biomarkers: alkenone and TEX〈sub〉86〈/sub〉. The alkenone‐based temperature estimates agree with previous Mg/Ca‐based SST reconstructions, supporting the existence of a warm‐water anomaly in the WTSA during MIS 6. On the other hand, TEX〈sub〉86〈/sub〉‐derived temperatures were up to 6°C colder than Mg/Ca‐ and alkenone‐based SST reconstructions. This discrepancy might be a result of a vertical migration of the TEX86 producers toward greater water depths where they feed on particles of organic matter. These migrations into deeper waters occurred during phases of increased river run‐off fluvial suspension input which enhanced surface primary productivity and facilitated vertical particle flux through the water column.〈/p〉
    Description: Key Points: 〈list list-type="bullet"〉 〈list-item〉 〈p xml:lang="en"〉Parallel Mg/Ca (〈italic〉Globigerinoides ruber〈/italic〉), alkenone and TEX〈sub〉86〈/sub〉‐based temperature estimates in the western tropical South Atlantic (WTSA) across Marine Isotope Stages (MIS) 6–5〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Mg/Ca and alkenones represent annual mean sea surface temperatures, but most TEX〈sub〉86〈/sub〉‐based temperatures deviate to colder values〈/p〉〈/list-item〉 〈list-item〉 〈p xml:lang="en"〉Anomalous sea surface warming in the WTSA during late MIS 6 appears as a robust signal〈/p〉〈/list-item〉 〈/list〉 〈/p〉
    Description: R/V METEOR
    Description: DFG
    Description: CNPq
    Description: FAPESP
    Description: Alexander von Humboldt‐Stiftung http://dx.doi.org/10.13039/100005156
    Description: https://doi.org/10.1594/PANGAEA.956207
    Keywords: ddc:551 ; Mg/Ca ; alkenones ; TEX86 ; MIS 6 ; Brazilian Margin ; MIS 5
    Language: English
    Type: doc-type:article
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  • 2
    ISSN: 1432-2145
    Keywords: Ubiquitin ; Tomato ; Maize ; Heat shock proteins ; Protein degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Ubiquitin is a ubiquitous protein involved in targeting proteins for degradation. Maize pollen was previously reported (Callis and Bedinger 1994) to show extremely low levels of ubiquitin monomer, and developmental significance was attributed to this surprising feature of maize pollen. However, we had previously shown (Muschietti et al. 1994) that tomato pollen had high levels of ubiquitin monomer. Here we show that pollen from most plant families has high levels of ubiquitin monomer. Most grasses tested show reduced levels of ubiquitin monomer, but some maize inbred lines have higher levels of ubiquitin monomer than other inbreds. There was no correlation between the level of ubiquitin monomer and either the monocotyledonous or tri-cellular condition of grass pollen or the dehydrated condition of mature pollen. Since many aspects of pollen development (i.e., wall formation, microspore mitosis, synthesis and storage of mRNAs and proteins, carbohydrates and lipids, dehydration at maturity) are stereotypical among all plant families, the reduced level of ubiquitin monomer in pollen of many grasses cannot be crucial for any feature of normal pollen development.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 100 (2000), S. 1190-1196 
    ISSN: 1432-2242
    Keywords: Key words Fluorescence in situ hybridization ; Genomic in situ hybridization ; Interspecific introgression ; Japanese bunching onion ; Onion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cytological analysis of (Allium cepa L.×Allium fistulosum L.)×A. cepa L. F1BC3 plants revealed most plants were diploid with 16 chromosomes. Karyotypes of these plants showed recombinant chromosomes. Fluorescence and genomic in situ hybridization patterns of interspecific F1 hybrid and F1BC3 plants revealed A. fistulosum chromosomes or chromosomal segments. A highly repetitive 376-bp DNA sequence and genomic DNA of A. fistulosum revealed similar telomeric hybridization sites when hybridized onto A. fistulosum chromosomes. Cytogenetic evidence showed that A. fistulosum DNA has recombined into the A. cepa genome.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2007. This is the author's version of the work. It is posted here by permission of National Academy of Sciences of the USA for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 9029-9034, doi:10.1073/pnas.0610552104.
    Description: Floodwaters in New Orleans from Hurricanes Katrina and Rita were observed to contain high levels of fecal indicator bacteria and microbial pathogens, generating concern about long-term impacts of these floodwaters on the sediment and water quality of the New Orleans area and Lake Pontchartrain. We show here that fecal indicator microbe concentrations in offshore waters from Lake Pontchartrain returned to prehurricane concentrations within 2 months of the flooding induced by these hurricanes. Vibrio and Legionella species within the lake were more abundant in samples collected shortly after the floodwaters had receded compared with samples taken within the subsequent 3 months; no evidence of a long-term hurricane-induced algal bloom was observed. Giardia and Cryptosporidium were detected in canal waters. Elevated levels of fecal indicator bacteria observed in sediment could not be solely attributed to impacts from floodwaters, as both flooded and nonflooded areas exhibited elevated levels of fecal indicator bacteria. Evidence from measurements of Bifidobacterium and bacterial diversity analysis suggest that the fecal indicator bacteria observed in the sediment were from human fecal sources. Epidemiologic studies are highly recommended to evaluate the human health effects of the sediments deposited by the floodwaters.
    Description: This work was funded by NSF-NIEHS Oceans and Human Health Program (NSF OCE0432368, OCE0432479, OCE0430724 and NIEHS P50 ES12736, ES012740, ES012742), the NSF-SGER Program (OCE 0554402, OCE 0554674, OCE 0554850, OCE0600130), the NSF-REU Program, and by the Georgia Sea Grant College Program (NA04OAR170033).
    Keywords: Lake Pontchartrain ; Water quality
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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