Stereospecific effect of hexachlorocyclohexane on activity and structure of soil methanotrophic communities

Mertens, Birgit; Boon, Nico; Verstraete, Willy

doi:10.1111/j.1462-2920.2005.00735.x

Cited by 66 publications

(52 citation statements)

References 44 publications

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“…To represent graphically the evenness of fungal community in wetlands, Pareto-Lorenz (PL) evenness curves were constructed based on the DGGE profiles (Mertens et al, 2005). The functional organization (F o ), which is determined based on PL curves, is defined as 'the ability of the community to organize in an adequate distribution of dominant microorganisms and resilient ones, condition that should assure the potentiality of counteracting the effect of a sudden stress exposure' (Marzorati et al, 2008).…”

Section: Community Analysismentioning

confidence: 99%

The biogeography of fungal communities in wetland sediments along the Changjiang River and other sites in China

et al. 2013

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Whether fungal community structure depends more on historical factors or on contemporary factors is controversial. This study used culture-dependent and -independent (polymerase chain reactiondenaturing gradient gel electrophoresis (PCR-DGGE)) methods to assess the influence of historical and contemporary factors on the distributions of fungi in the wetland sediments at 10 locations along the Changjiang River and at 10 other locations in China. The culture-dependent approach detected greater species diversity (177 operational taxonomic units (OTUs)) than PCR-DGGE analysis (145 OTUs), and the species in the genera of Penicillium (relative frequency ¼ 16.8%), Fusarium (15.4%), Aspergillus (7.6%), Trichoderma (5.8%) and Talaromyces (4.2%) were dominant. On the basis of DGGE data, fungal diversity along the Changjiang River increased from upstream to downstream; altitude explained 44.8% of this variation in diversity. And based on the data from all 20 locations, the fungal communities were geographically clustered into three groups: Southern China, Northern China and the Qinghai-Tibetan Plateau. Multivariate regression tree analysis for data from the 20 locations indicated that the fungal community was influenced primarily by location (which explained 61.8% of the variation at a large scale), followed by total potassium (9.4%) and total nitrogen (3.5%) at a local scale. These results are consistent with the concept that geographic distance is the dominant factor driving variation in fungal diversity at a regional scale (1000-4000 km), whereas environmental factors (total potassium and total nitrogen) explain variation in fungal diversity at a local scale (o1000 km).

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Section: Community Analysismentioning

confidence: 99%

The biogeography of fungal communities in wetland sediments along the Changjiang River and other sites in China

et al. 2013

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“…; e = H/ln (S); (v) the ParetoLorenz eveness curves (PL curves), based on the DGGE profile using the Lorenz-Gini method (Mertens et al, 2005;Marzorati et al, 2008;Wittebolle et al, 2009) and constructed by ranking the respective DGGE bands for each sample from high to low intensity and using the cumulative proportion of bands and their respective cumulative proportions of intensities as X-and Y-axis; and (vi) the community organization, which describes the evenness (equality) of the archaeal population and is the normalized area between a given PL-curve and the perfect evenness line. community organization ranges from 0 to 100 and represents a single value that describes a specific degree of evenness.…”

Section: Vfasmentioning

confidence: 99%

Effect of supplementing coconut or krabok oil, rich in medium-chain fatty acids on ruminal fermentation, protozoa and archaeal population of bulls

Panyakaew

Boon

Goel

et al. 2013

Animal

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Medium-chain fatty acids (MCFA), for example, capric acid (C10:0), myristic (C14:0) and lauric (C12:0) acid, have been suggested to decrease rumen archaeal abundance and protozoal numbers. This study aimed to compare the effect of MCFA, either supplied through krabok (KO) or coconut (CO) oil, on rumen fermentation, protozoal counts and archaeal abundance, as well as their diversity and functional organization. KO contains similar amounts of C12:0 as CO (420 and 458 g/kg FA, respectively), but has a higher proportion of C14:0 (464 v. 205 g/kg FA, respectively). Treatments contained 35 g supplemental fat per kg DM: a control diet with tallow (T); a diet with supplemental CO; and a diet with supplemental KO. A 4th treatment consisted of a diet with similar amounts of MCFA (i.e. C10:0 + C12:0 + C14:0) from CO and KO. To ensure isolipidic diets, extra tallow was supplied in the latter treatment (KO + T). Eight fistulated bulls (two bulls per treatment), fed a total mixed ration predominantly based on cassava chips, rice straw, tomato pomace, rice bran and soybean meal (1.5% of BW), were used. Both KO and CO increased the rumen volatile fatty acids, in particular propionate and decreased acetate proportions. Protozoal numbers were reduced through the supplementation of an MCFA source (CO, KO and KO + T), with the strongest reduction by KO. Quantitative real-time polymerase chain reaction assays based on archaeal primers showed a decrease in abundance of Archaea when supplementing with KO and KO + T compared with T and CO. The denaturing gradient gel electrophoresis profiles of the rumen archaeal population did not result in a grouping of treatments. Richness indices were calculated from the number of DGGE bands, whereas community organization was assessed from the Pareto-Lorenz eveness curves on the basis of DGGE band intensities. KO supplementation (KO and KO + T treatments) increased richness and evenness within the archaeal community. Further research including methane measurements and productive animals should elucidate whether KO could be used as a dietary methane mitigation strategy.Keywords: krabok oil, coconut oil, rumen protozoa, Archaea, microbial community organization Implication Krabok seeds are widely available in South-East Asian forests, contain large amounts of fat and as such are of interest to be used as a fat source in animal diets by local farmers. As krabok oil (KO) almost exclusively consists of lauric and myristic acid, it not only should be considered an energy supplier and its potential as modifier of the rumen microbial community was assessed here. KO showed potential to reduce rumen protozoal and archaeal numbers and shift rumen fermentation towards more propionate at smaller quantities than coconut oil (CO), another more common source of lauric and myristic acid.

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“…Up to now, diversity has been mainly measured statically, based on indices such as Shannon and Simpson indices. By adding Lorenz curves, a nonambiguous graphical presentation of species evenness can be provided (31,35,42), investigating interspecies abundance ratios and thus the internal community structure. Besides the importance of the community diversity and composition at one time point, the dynamics of microbial communities can play an important role in the functionality of a system (49).…”

mentioning

confidence: 99%

Quantifying Community Dynamics of Nitrifiers in Functionally Stable Reactors

Wittebolle

Vervaeren

Verstraete

et al. 2008

Appl Environ Microbiol

Self Cite

183

137

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A sequential batch reactor (SBR) and a membrane bioreactor (MBR) were inoculated with the same sludge from a municipal wastewater treatment plant, supplemented with ammonium, and operated in parallel for 84 days. It was investigated whether the functional stability of the nitrification process corresponded with a static ammonia-oxidizing bacterial (AOB) community. The SBR provided complete nitrification during nearly the whole experimental run, whereas the MBR showed a buildup of 0 to 2 mg nitrite-N liter ؊1 from day 45 until day 84. Based on the denaturing gradient gel electrophoresis profiles, two novel approaches were introduced to characterize and quantify the community dynamics and interspecies abundance ratios: (i) the rate of change [⌬ t(week) ] parameter and (ii) the Pareto-Lorenz curve distribution pattern. During the whole sampling period, it was observed that neither of the reactor types maintained a static microbial community and that the SBR evolved more gradually than the MBR, particularly with respect to AOB (i.e., average weekly community changes of 12.6% ؎ 5.2% for the SBR and 24.6% ؎ 14.3% for the MBR). Based on the Pareto-Lorenz curves, it was observed that only a small group of AOB species played a numerically dominant role in the nitritation of both reactors, and this was true especially for the MBR. The remaining less dominant species were speculated to constitute a reserve of AOB which can proliferate to replace the dominant species. The value of these parameters in terms of tools to assist the operation of activated-sludge systems is discussed. Fernandez et al. (12) demonstrated that ecosystem stability encompasses a broad spectrum of definitions. These definitions resolve into two components: the measurable functional properties of the ecosystem and the change over time of the community composition. Frequently, only the functional parameters are evaluated (37), but recently attempts were made to relate (dys)functioning with the structure of a microbial community (13,25,46,49). It was found that highly dynamic communities can still maintain a stable ecosystem function (12, 25).Curtis and Sloan (8) postulated that the relationship between structure and function in a microbial community can be evaluated only through an understanding of the source of diversity from which the community is drawn, named the global reservoir or metacommunity. Up to now, diversity has been mainly measured statically, based on indices such as Shannon and Simpson indices. By adding Lorenz curves, a nonambiguous graphical presentation of species evenness can be provided (31,35,42), investigating interspecies abundance ratios and thus the internal community structure. Besides the importance of the community diversity and composition at one time point, the dynamics of microbial communities can play an important role in the functionality of a system (49). Nevertheless, due to infrequent sampling, the dynamics of functionally stable microbial communities has not yet been quantified in terms of a rate of change on a sho...

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Stereospecific effect of hexachlorocyclohexane on activity and structure of soil methanotrophic communities

Cited by 66 publications

References 44 publications

The biogeography of fungal communities in wetland sediments along the Changjiang River and other sites in China

The biogeography of fungal communities in wetland sediments along the Changjiang River and other sites in China

Effect of supplementing coconut or krabok oil, rich in medium-chain fatty acids on ruminal fermentation, protozoa and archaeal population of bulls

Quantifying Community Dynamics of Nitrifiers in Functionally Stable Reactors

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