Microstructure and Biogeochemistry of the Organically Preserved Ediacaran MetazoanSabellidites

2014 ◽  
Vol 88 (2) ◽  
pp. 224-239 ◽  
Author(s):  
Małgorzata Moczydłowska ◽  
Frances Westall ◽  
Frédéric Foucher

Metazoans (multicellular animals) evolved during the Ediacaran Period as shown by the record of their imprints, carbonaceous compressions, trace fossils, and organic bodies and skeletal fossils. Initial evolutionary experiments produced unusual bodies that are poorly understood or conceived of as non-metazoan. It is accepted that sponges, ctenophorans, cnidarians, placozoans, and bilaterians were members of the Ediacaran fauna, many of which have uncertain affinities. The fossilSabellidites cambriensisYanishevsky, 1926, derived from the terminal Ediacaran strata, is the earliest known organically preserved animal that belonged to a newly evolving fauna, which replaced the Ediacara-type metazoans. Morphologically simple soft-bodied tubular fossils, such asS. cambriensis, and biomineralized, as contemporaneousSinotubulitessp., are not easy to recognize phylogenetically because many unrelated organisms developed encasing tubes independently. Therefore, in addition to morphologic information, evidence derived from the microstructure of the organic wall and its biochemistry may be vital to resolving fossil origins and phylogenetic relationships. Here we present morphological, microstructural and biogeochemical studies onS. cambriensisusing various microscopic and spectroscopic techniques, which provide new evidence that supports its siboglinid, annelidan affinity. The late Ediacaran age ofSabelliditesfossil constrains the minimum age of siboglinids and the timing of the divergence of including them annelids by fossil record and this could be tested using molecular clock estimates. The fine microstructure of the organic tube inSabelliditesis multi-layered and has discrete layers composed of differently orientated and perfectly shaped fibers embedded in an amorphous matrix. The highly ordered and specific pattern of fiber alignment (i.e., the texture of organic matter) is similar to that of representatives of the family Siboglinidae. The biogeochemistry of the organic matter that comprised the tube, which was inferred from its properties, composition, and microstructure, is consistent with chitin and proteins as in siboglinids.

2013 ◽  
Vol 13 (1) ◽  
pp. 349-352
Author(s):  
Sérgio Roberto Rodrigues ◽  
Anderson Puker

Coleoptera of the family Geotrupidae play an important ecological role in the decomposition of animal and plant organic matter. In Brazil there is little information on the diversity and distribution of this group, thus, this work had a purpose to study Geotrupidae species, occurring in Aquidauana, MS. A survey for geotrupids was conducted in Aquidauana, Mato Grosso do Sul, Brazil. Beetles were captured using a light trap over a period of two years, from January 2006 to December 2007. A total of 907 specimens were collected and identified to eight species. From the subfamily Bolboceratinae, the species identified were Bolbapium minutum (Luederwaldt, 1929) and Pereirabolbus castaneus (Klug, 1845). In the subfamily Athyreinae the species identified were Athyreus bilobus Howden & Martínez, 1978, Parathyreus aff. bahiae, Neoathyreus aff. julietae, N. sexdentatus Laporte, 1840, N. centromaculatus (Felsche, 1909) and N. goyasensis (Boucomont, 1902). Four species (A. bilobus, N. centromaculatus, N. goyasensis and P. castaneus) are reported for the first time in Aquidauana, MS, Brazil. The most abundant species, representing 85.9% of the total capture, was B. minutum. The greatest numbers of specimens was caught from October to December of both years of the study.


2020 ◽  
Vol 57 (6) ◽  
pp. 671-677 ◽  
Author(s):  
Yah-Huei Wu-Chou ◽  
Kuo-Ting Philip Chen ◽  
Yi-Chieh Lu ◽  
Yin-Ting Lin ◽  
Hsien-Fang Chang ◽  
...  

Objective: Nonsyndromic oral clefts are common birth defect with complex etiology. In the present study, we attempt to further validate the possible role for ABCA4 and ARHGAP29 in the susceptibility to nonsyndromic oral clefts. Design: We performed allelic transmission disequilibrium test analysis, on 10 eligible single nucleotide polymorphisms (SNPs) and SNP haplotypes using the Family-Based Association Test. Participants: The study sample consisted of 334 case–parent trios of nonsyndromic oral clefts from Taiwanese population, separated into nonsyndromic cleft lip with or without cleft palate (NSCL/P) and nonsyndromic cleft palate only (NSCPO) groups. Results: We found only the SNP rs560426 within the ABCA4 gene showed strong association with NSCPO ( P = .03498; Permuted P = .05382). No association between other 9 selected SNPs in ABCA4-ARHGAP29 region and the risk of nonsyndromic oral clefts was found. For the haplotype analyses, we found only haplotype T-C (rs570926 and rs3789431) in ABCA4 block 2 showed significant association with nonsyndromic NSCL/P in these Taiwanese trios. Conclusions: We used a family-based analysis in 334 Taiwanese case–parent trios to validate the possible role for ABCA4 and ARHGAP29 in the susceptibility to nonsyndromic oral clefts. This study provides a new evidence for an association between the intron variant rs560426 within ABCA4 and nonsyndromic cleft palate which may contribute their regulatory role in craniofacial development.


Quaerendo ◽  
1984 ◽  
Vol 14 (4) ◽  
pp. 247-272 ◽  
Author(s):  
Paul Valkema Blouw

AbstractFrom the chronicles of the Family of Love we know that, besides printers in Deventer and later in Cologne, both Plantin and Augustijn van Hasselt printed for this religious sect. On the basis of this information quite a large number of publications have hitherto been attributed to Plantin, while only one single edition in Latin was reckoned to be the work of Augustijn. An analysis of the typography, however, shows that apart from Hendrik Niclaes's chief work, Den Spegel der Gherechticheyt, Plantin only printed two of his minor writings and that all the other ascriptions to Plantin must be revised in favour of Augustijn van Hasselt. In 1561-2 Augustijn was running a printing shop in the Dutch town of Kampen, specially set up by HN for the purpose of publishing those of his works that had not previously been printed. Plantin, who was partly involved in this enterprise, took the opportunity to have a book printed on this press for his publishing business. The analysis providing the typographical evidence of this collaboration proves for the first time the accuracy of the literary sources as regards Plantin's involvement in the publication of the works of Hendrik Niclaes. In the presentation of the new evidence it was necessary to establish more clearly the date of Plantin's '[1561]' inventory and which roman and German types he owned at what times. The article ends with some notes regarding the end of the 'Bohmbargen' press at Cologne.


2021 ◽  
Vol 13 (3) ◽  
pp. 1-30
Author(s):  
Itzik Fadlon ◽  
Torben Heien Nielsen

We provide new evidence on households’ labor supply responses to fatal and severe nonfatal health shocks in the short run and medium run. To identify causal effects, we leverage administrative data on Danish families and construct counterfactuals using households that experience the same event a few years apart. Fatal events lead to considerable increases in surviving spouses’ labor supply, which the evidence suggests is driven by families who experience significant income losses. Nonfatal shocks have no meaningful effects on spousal labor supply, consistent with their adequate insurance coverage. The results support self-insurance as a driving mechanism for the family labor supply responses. (JEL D12, D15, G22, I12, J22)


2021 ◽  
Author(s):  
Jerzy Weber ◽  
Elżbieta Jamroz ◽  
Andrzej Kocowicz ◽  
Magdalena Debicka ◽  
Jakub Bekier ◽  
...  

<p>Methods of isolation of the humin fraction can be divided into two main groups: (1) extraction of humic (HA) and fulvic (FA) acids followed by extraction of humin with different organic solvents, and (2) extraction of HA and FA followed by removal of soil mineral fraction. To isolate the large amounts of humin necessary to study the interactions of this fraction with pesticides, we examined some modifications of the latter method.</p><p>The first step was to separate HA and FA according to a modified IHSS method (Swift 1996). HA and FA were extracted with 0.1 M NaOH with a 5:1 ratio of extractant to soil. 20 hours shaking was found to be more effective, but 4 hours shaking provided the advantage of being able to extract twice a day,  which ultimately shortened the procedure time.</p><p>The HA and FA free residue was then digested to remove mineral components. We used several (up to 8 weeks) digestions with 10% HF/HCl as higher concentrations of HF can result in structural alteration of the organic compounds (Hayes et al. 2017). While HF/HCl treatment can lead to hydrolysis and loss of polysaccharide and protein materials (Stevenson 1994), the advantage of using HF is the removal of paramagnetic compounds (such as Fe), which facilitates the use of spectroscopic techniques to characterize humin. In contrast to the procedures for only increasing the concentration of organic matter (Schmidt et al. 1997), the sample was digested until the mineral fraction not complexed with humin was completely digested. We tested different modes of mineral fraction digestion in 10% HF/HCl using polyethylene centrifuge bottles. Occasional shaking once a day had the same effect as continuous shaking. It takes 6 weeks to digest 200 g of pure sand in a 1000 cm<sup>3</sup> bottle, when the HF/HCL was weekly replaced. After replacing HF/HCl every 2 weeks, the digestion time of the same material increased to 8 weeks.</p><p>After treatment with HF/HCl, the residue was rinsed with 10% HCl to remove secondary minerals. The residue was washed with distilled water until the neutral pH and then dialyzed to a negative Cl<sup>−</sup> test with AgNO<sub>3</sub>. Then the humin fraction was freeze dried. </p><p> </p><p>Literature</p><p>Hayes M.H.B., Mylotte R., Swift R.S. 2017. Humin: Its Composition and Importance in Soil Organic Matter. In: Sparks D.L. (ed) Advances in Agronomy, Vol. 143, Academic Press, Burlington, 47–138.</p><p>Schmidt, M.W.I., Knicker, H., Hatcher, P.G., Kögel-Knabner, I. 1997. Improvement of 13C and 15N CPMAS NMR spectra of bulk soils, particle size fractions and organic material by treatment with 10% hydrofluoric acid. European Journal of Soil Science, 48, 319-328.</p><p>Stevenson F.J. 1994. Humus Chemistry; Genesis, Composition, Reaction. 2nd ed. John Wiley & Sons., New York.</p><p>Swift R.S. 1996. Organic matter characterization. In: Sparks, D.L., et al. (Ed.), Methods of Soil Analysis. Part 3. Chemical Methods - Soil Science Society of America, Book Series no 5,  1011-1069.</p><p> </p><p>Acknowledgements</p><p>This work was supported by the National Science Center (NCN) Poland (project No 2018/31/B/ST10/00677 “Chemical and spectroscopic properties of soil humin fraction in relation to their mutual interaction with pesticides").</p>


2003 ◽  
Author(s):  
Benny Chefetz ◽  
Baoshan Xing

Sorption of hydrophobic compounds to aliphatic components of soil organic matter (SOM) is poorly understood even though these aliphatic carbons are a major fraction of SOM. The main source of aliphatic compounds in SOM is above- and below-ground plant cuticular materials (cutin, cutan and suberin). As decomposition proceeds, these aliphatic moieties tend to accumulate in soils. Therefore, if we consider that cuticular material contributes significantly to SOM, we can hypothesize that the cuticular materials play an important role in the sorption processes of hydrophobic compounds (including pesticides) in soils, which has not yet been studied. The overall goal of this research was to illustrate the mechanism and significance of the refractory aliphatic structures of SOM in sorbing hydrophobic compounds (nonionic and weakly polar pesticides). The importance of this study is related to our ability to demonstrate the sorption relationship between key pesticides and an important fraction of SOM. The specific objectives of the project were: (1) To isolate and characterize cuticular fractions from selected plants; (2) To investigate the sorption mechanism of key hydrophobic pesticides and model compounds to cuticular plant materials; (3) To examine the sorption mechanisms at the molecular level using spectroscopic techniques; (4) To investigate the sorption of key hydrophobic pesticides to synthetic polymers; (5) To evaluate the content of cuticular materials in agricultural soils; and (6) To study the effect of incubation of plant cuticular materials in soils on their sorptive capabilities. This project demonstrates the markedly high sorption capacity of various plant cuticular fractions for hydrophobic organic compounds (HOCs) and polar organic pollutants. Both cutin (the main polymer of the cuticle) and cutan biopolymers exhibit high sorption capability even though both sorbents are highly aliphatic in nature. Sorption by plant cuticular matter occurs via hydrophobic interactions and H-bonding interactions with polar sorbates. The cutin biopolymer seems to facilitate reversible and noncompetitive sorption, probably due to its rubbery nature. On the other hand, the epicuticular waxes facilitate enhance desorption in a bi-solute system. These processes are possibly related to phase transition (melting) of the waxes that occur in the presence of high solute loading. Moreover, our data highlight the significance of polarity and accessibility of organic matter in the uptake of nonpolar and polar organic pollutants by regulating the compatibility of sorbate to sorbent. In summary, our data collected in the BARD project suggest that both cutin and cutan play important roles in the sorption of HOCs in soils; however, with decomposition the more condensed structure of the cutin and mainly the cutan biopolymer dominated sorption to the cuticle residues. Since cutin and cutan have been identified as part of SOM and humic substances, it is suggested that retention of HOCs in soils is also controlled by these aliphatic domains and not only by the aromaticrich fractions of SOM.


2000 ◽  
Vol 68 (4) ◽  
pp. 429-433 ◽  
Author(s):  
V. U. Ahmad ◽  
M. Zahid ◽  
M. S. Ali ◽  
S. Ahmad ◽  
Z. Ali ◽  
...  

Salvia bucharica belonging to the family Lamiaceae (Labiatae), afforded a new aromatic ester named buchariate [1-(p-hydroxybenzoyloxy)-3-oxo-octane (1)] along with twelve known constituents for the first time from our investigated source. The structures of all the isolated constituents were determined through spectroscopic techniques and comparison with literature values. The structure of new constituent (1) was elucidated through extensive 2-D NMR experiments.


2015 ◽  
Vol 12 (23) ◽  
pp. 6999-7011 ◽  
Author(s):  
P. Glaz ◽  
J.-P. Gagné ◽  
P. Archambault ◽  
P. Sirois ◽  
C. Nozais

Abstract. Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a 3-year period in eight eastern Boreal Shield lakes: four lakes were studied before, 1 and 2 years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering 1 year before and 1 year after the perturbation only. At 1 year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~ 15 mgC L−1 compared to 12.5 mgC L−1 in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterized with spectroscopic techniques. These results confirm an impact of forestry activities 1 year after the perturbation. However, this effect seems to be mitigated 2 years after, indicating that the system shows high resilience and may be able to return to its original condition in terms of water quality parameters assessed in this study.


Sign in / Sign up

Export Citation Format

Share Document