scholarly journals Association of Earthworm-Denitrifier Interactions with Increased Emission of Nitrous Oxide from Soil Mesocosms Amended with Crop Residue

2011 ◽  
Vol 77 (12) ◽  
pp. 4097-4104 ◽  
Author(s):  
Lucas D. Nebert ◽  
Jaap Bloem ◽  
Ingrid M. Lubbers ◽  
Jan Willem van Groenigen
Keyword(s):  
Nitrous Oxide ◽  
Enzyme Activity ◽  
Feeding Strategy ◽  
Bulk Soil ◽  
Lumbricus Rubellus ◽  
Arable Soils ◽  
Content Type ◽  
Fresh Organic Matter ◽  
Soil Mesocosms ◽  
Denitrification Enzyme Activity

ABSTRACTEarthworm activity is known to increase emissions of nitrous oxide (N2O) from arable soils. Earthworm gut, casts, and burrows have exhibited higher denitrification activities than the bulk soil, implicating priming of denitrifying organisms as a possible mechanism for this effect. Furthermore, the earthworm feeding strategy may drive N2O emissions, as it determines access to fresh organic matter for denitrification. Here, we determined whether interactions between earthworm feeding strategy and the soil denitrifier community can predict N2O emissions from the soil. We set up a 90-day mesocosm experiment in which15N-labeled maize (Zea maysL.) was either mixed in or applied on top of the soil in the presence or absence of the epigeic earthwormLumbricus rubellusand/or the endogeic earthwormAporrectodea caliginosa. We measured N2O fluxes and tested the bulk soil for denitrification enzyme activity and the abundance of 16S rRNA and denitrifier genesnirSandnosZthrough real-time quantitative PCR. Compared to the control,L. rubellusincreased denitrification enzyme activity and N2O emissions on days 21 and 90 (day 21,P= 0.034 andP= 0.002, respectively; day 90,P= 0.001 andP= 0.007, respectively), as well as cumulative N2O emissions (76%;P= 0.014).A. caliginosaactivity led to a transient increase of N2O emissions on days 8 to 18 of the experiment. Abundance ofnosZwas significantly increased (100%) on day 90 in the treatment mixture containingL. rubellusalone. We conclude thatL. rubellusincreased cumulative N2O emissions by affecting denitrifier community activity via incorporation of fresh residue into the soil and supplying a steady, labile carbon source.

Denitrification Enzyme Activity of Fringe Salt Marshes in New England (USA)

2004 ◽  
Vol 33 (3) ◽  
pp. 1144 ◽  
Author(s):  
Cathleen Wigand ◽  
Richard A. McKinney ◽  
Marnita M. Chintala ◽  
Michael A. Charpentier ◽  
Peter M. Groffman
Keyword(s):  
Enzyme Activity ◽  
New England ◽  
Salt Marshes ◽  
Denitrification Enzyme Activity

First evidence for tooth-tooth occlusion in a ctenochasmatid pterosaur from the Early Cretaceous Jehol Biota

2021 ◽  
pp. SP521-2021-141
Author(s):  
Chang-Fu Zhou ◽  
Xinyue Wang ◽  
Jiahao Wang
Keyword(s):  
Early Cretaceous ◽  
Feeding Strategy ◽  
Three Dimensional ◽  
Tooth Wear ◽  
First Record ◽  
Jehol Biota ◽  
Content Type ◽  
Dimensional Reconstruction ◽  
Supplementary Material ◽  
Ct Data

AbstractCtenochasmatid pterosaurs flourished and diversified in the Early Cretaceous Jehol Biota. Here, a partial mandible of Forfexopterus is described based on a three-dimensional reconstruction using high-resolution X-ray Computed Tomography (CT) data. The first nine pairs of functional teeth of the rostral dentition revealed along with their replacements. The functional teeth are evenly arranged with a tooth density of 2.2 teeth/cm. The tooth crown is distinctly reduced from its base to the tip, and framed by two weak ridges, possibly as a pair of vestigial carinae. The replacement teeth are sharp and pointed, and have erupted slightly against the medial surface of the functional teeth. Surprisingly, tooth wear is observed in this specimen, the first record of tooth-tooth occlusion in ctenochasmatids. The wear facets exhibit high-angled lingual and lower-angled labial facets, implying a tooth-tooth occlusion in pterosaur clade. This discovery indicates that the Jehol ctenochasmatids possibly employed a more active feeding strategy than other filter-feeding pterosaurs (e.g. Ctenochasma, Pterodaustro, Gnathosaurus).Supplementary material at https://doi.org/10.6084/m9.figshare.c.5722060

Digestive enzyme and gut surfactant activity of detritivorous gizzard shad (Dorosoma cepedianum)

2000 ◽  
Vol 57 (6) ◽  
pp. 1113-1119 ◽  
Author(s):  
James C Smoot ◽  
Robert H Findlay
Keyword(s):  
Enzyme Activity ◽  
Protease Activity ◽  
Feeding Strategy ◽  
Digestive Enzyme ◽  
Artificial Substrates ◽  
Gizzard Shad ◽  
Dorosoma Cepedianum ◽  
Digestive Physiology ◽  
Protease Enzyme ◽  
Surfactant Activity

Measuring digestive enzyme and surfactant activities tested specialization of gizzard shad (Dorosoma cepedianum) digestive physiology to a detritivorous feeding strategy. Digestive enzyme activity was measured in adult and larval gizzard shad using fluorescently labeled artificial substrates. Surfactant activity in gizzard shad was measured by comparing gut juice drop diameters over a range of dilutions. Enzyme activity in the ceca region of adult gizzard shad was high for esterase, beta-glucosidase, lipase, and protease. Enzyme activity was lower in posterior intestine sections than in anterior intestine sections, although protease activity remained high for the greatest distance in the intestine. Micelles were detected in adult gizzard shad gut juice, and surfactant activity was greatest in the ceca region. Larval gizzard shad protease activity was similar to that of adult fish, and surfactants were below their critical micelle concentration. Gizzard shad coupled digestive physiology with gut anatomy to obtain nutrients from detritus, and these adaptations may explain elevated growth rates observed in these fish when they are planktivorous.

scholarly journals Draft Genome Sequence of Bacillus sp. Strain IGA-FME-2, Isolated from the Bulk Soil of Soybean (Glycine max L.) in Northeast China

2021 ◽  
Vol 10 (16) ◽  
Author(s):  
Zhenhua Yu ◽  
Sergio de los Santos-Villalobos ◽  
Yansheng Li ◽  
Jian Jin ◽  
Fannie Isela Parra Cota ◽  
...  
Keyword(s):  
Glycine Max ◽  
Draft Genome ◽  
Gc Content ◽  
Single Copy ◽  
Bulk Soil ◽  
23S Rrna ◽  
Protein Coding ◽  
Content Type ◽  
Protein Coding Genes ◽  
Glycine Max L

ABSTRACT Here, we present the draft genome of Bacillus sp. strain IGA-FME-2. This strain was isolated from the bulk soil of soybean (Glycine max L.). Its genome consists of 3,810 protein-coding genes, 44 tRNAs, two 16S rRNAs, and a single copy of 23S rRNA, with a GC content of 46.4%.

scholarly journals Quantitative Analysis of Lysobacter Predation

2015 ◽  
Vol 81 (20) ◽  
pp. 7098-7105 ◽  
Author(s):  
Ivana Seccareccia ◽  
Christian Kost ◽  
Markus Nett
Keyword(s):  
Experimental Data ◽  
Feeding Strategy ◽  
Predatory Behavior ◽  
Bacterial Group ◽  
Potential Prey ◽  
Bacterial Populations ◽  
Content Type ◽  
Predator Prey ◽  
Prey Killing ◽  
Predatory Potential

ABSTRACTBacteria of the genusLysobacterare considered to be facultative predators that use a feeding strategy similar to that of myxobacteria. Experimental data supporting this assumption, however, are scarce. Therefore, the predatory activities of threeLysobacterspecies were tested in the prey spot plate assay and in the lawn predation assay, which are commonly used to analyze myxobacterial predation. Surprisingly, only one of the testedLysobacterspecies showed predatory behavior in the two assays. This result suggested that not allLysobacterstrains are predatory or, alternatively, that the assays were not appropriate for determining the predatory potential of this bacterial group. To differentiate between the two scenarios, predation was tested in a CFU-based bioassay. For this purpose, defined numbers ofLysobactercells were mixed together with potential prey bacteria featuring phenotypic markers, such as distinctive pigmentation or antibiotic resistance. After 24 h, cocultivated cells were streaked out on agar plates and sizes of bacterial populations were individually determined by counting the respective colonies. Using the CFU-based predation assay, we observed thatLysobacterspp. strongly antagonized other bacteria under nutrient-deficient conditions. Simultaneously, theLysobacterpopulation was increasing, which together with the killing of the cocultured bacteria indicated predation. Variation of the predator/prey ratio revealed that all threeLysobacterspecies tested needed to outnumber their prey for efficient predation, suggesting that they exclusively practiced group predation. In summary, the CFU-based predation assay not only enabled the quantification of prey killing and consumption byLysobacterspp. but also provided insights into their mode of predation.

scholarly journals Extracellular Enzyme Activity and Microbial Diversity Measured on Seafloor Exposed Basalts from Loihi Seamount Indicate the Importance of Basalts to Global Biogeochemical Cycling

2014 ◽  
Vol 80 (16) ◽  
pp. 4854-4864 ◽  
Author(s):  
Myrna E. Jacobson Meyers ◽  
Jason B. Sylvan ◽  
Katrina J. Edwards
Keyword(s):  
Enzyme Activity ◽  
Microbial Communities ◽  
Enzyme Activities ◽  
Leucine Aminopeptidase ◽  
Extracellular Enzyme ◽  
Basaltic Rock ◽  
Rrna Gene ◽  
Content Type ◽  
Shelf Sediments ◽  
Potential Enzyme Activity

ABSTRACTSeafloor basalts are widely distributed and host diverse prokaryotic communities, but no data exist concerning the metabolic rates of the resident microbial communities. We present here potential extracellular enzyme activities of leucine aminopeptidase (LAP) and alkaline phosphatase (AP) measured on basalt samples from different locations on Loihi Seamount, HI, coupled with analysis of prokaryotic biomass and pyrosequencing of the bacterial 16S rRNA gene. The community maximum potential enzyme activity (Vmax) of LAP ranged from 0.47 to 0.90 nmol (g rock)−1h−1; theVmaxfor AP was 28 to 60 nmol (g rock)−1h−1. TheKmof LAP ranged from 26 to 33 μM, while theKmfor AP was 2 to 7 μM. Bacterial communities on Loihi basalts were comprised primarily ofAlpha-,Delta-, andGammaproteobacteria,Bacteroidetes, andPlanctomycetes. The putative ability to produce LAP is evenly distributed across the most commonly detected bacterial orders, but the ability to produce AP is likely dominated by bacteria in the ordersXanthomonadales,Flavobacteriales, andPlanctomycetales. The enzyme activities on Loihi basalts were compared to those of other marine environments that have been studied and were found to be similar in magnitude to those from continental shelf sediments and orders of magnitude higher than any measured in the water column, demonstrating that the potential for exposed basalts to transform organic matter is substantial. We propose that microbial communities on basaltic rock play a significant, quantifiable role in benthic biogeochemical processes.

Nitrous oxide emissions from fertilised UK arable soils: Fluxes, emission factors and mitigation

2015 ◽  
Vol 212 ◽  
pp. 134-147 ◽  
Author(s):  
M.J. Bell ◽  
N. Hinton ◽  
J.M. Cloy ◽  
C.F.E. Topp ◽  
R.M. Rees ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Emission Factors ◽  
Nitrous Oxide Emissions ◽  
Arable Soils
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