scholarly journals Impact of Protists on the Activity and Structure of the Bacterial Community in a Rice Field Soil

2006 ◽  
Vol 72 (8) ◽  
pp. 5436-5444 ◽  
Author(s):  
Jun Murase ◽  
Matthias Noll ◽  
Peter Frenzel
Keyword(s):  
Surface Layer ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Subsurface Layer ◽  
Molecular Ecology ◽  
Rflp Analysis ◽  
Small Subunit ◽  
Rice Fields ◽  
Bacterial Assemblage ◽  
Protistan Grazing ◽  
The Impact

ABSTRACT Flooded rice fields have become a model system for the study of soil microbial ecology. In Italian rice fields, in particular, aspects from biogeochemistry to molecular ecology have been studied, but the impact of protistan grazing on the structure and function of the prokaryotic community has not been examined yet. We compared an untreated control soil with a γ-radiation-sterilized soil that had been reinoculated with a natural bacterial assemblage. In order to verify that the observed effects were due to protistan grazing and did not result from sterilization, we set up a third set of microcosms containing sterilized soil that had been reinoculated with natural assemblage bacteria plus protists. The spatial and temporal changes in the protistan and prokaryotic communities were examined by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) analysis, respectively, both based on the small-subunit gene. Sequences retrieved from DGGE bands were preferentially affiliated with Cercozoa and other bacteriovorous flagellates. Without protists, the level of total DNA increased with incubation time, indicating that the level of the microbial biomass was elevated. Betaproteobacteria were preferentially preyed upon, while low-G+C-content gram-positive bacteria became more dominant under grazing pressure. The bacterial diversity detectable by T-RFLP analysis was greater in the presence of protists. The level of extractable NH4 + was lower and the level of extractable SO4 2− was higher without protists, indicating that nitrogen mineralization and SO4 2− reduction were stimulated by protists. Most of these effects were more obvious in the partially oxic surface layer (0 to 3 mm), but they could also be detected in the anoxic subsurface layer (10 to 13 mm). Our observations fit well into the overall framework developed for protistan grazing, but with some modifications pertinent to the wetland situation: O2 was a major control, and O2 availability may have limited directly and indirectly the development of protists. Although detectable in the lower anoxic layer, grazing effects were much more obvious in the partially oxic surface layer.

scholarly journals Springtime Upwelling and Its Formation Mechanism in Coastal Waters of Manaung Island, Myanmar

2020 ◽  
Vol 12 (22) ◽  
pp. 3777
Author(s):  
Yuhui Li ◽  
Yun Qiu ◽  
Jianyu Hu ◽  
Cherry Aung ◽  
Xinyu Lin ◽  
...  
Keyword(s):  
Surface Layer ◽  
Satellite Remote Sensing ◽  
Subsurface Layer ◽  
World Ocean ◽  
Remote Sensing Data ◽  
Remote Forcing ◽  
Forcing Mechanisms ◽  
World Ocean Atlas ◽  
The Impact ◽  
Local Wind Forcing

Multisource satellite remote sensing data and the World Ocean Atlas 2018 (WOA18) temperature and salinity dataset have been used to analyze the spatial distribution, variability and possible forcing mechanisms of the upwelling off Manaung Island, Myanmar. Signals of upwelling exist off the coasts of Manaung Island, in western Myanmar during spring. It appears in February, reaches its peak in March and decays in May. Low-temperature (<28.3 °C) and high-salinity (>31.8 psu) water at the surface of this upwelling zone is caused by the upwelling of seawater from a depth below 100 m. The impact of the upwelling on temperature is more significant in the subsurface layer than that in the surface layer. In contrast, the impact of the upwelling on salinity in the surface layer is more significant. Further research reveals that the remote forcing from the equator predominantly induces the evolution of the upwelling, while the local wind forcing also contributes to strengthen the intensity of the upwelling during spring.

Gastrointestinal and Microbial Responses to Sulfate-Supplemented Drinking Water in Mice

2003 ◽  
Vol 228 (4) ◽  
pp. 424-433 ◽  
Author(s):  
Bart Deplancke ◽  
Kai Finster ◽  
W Vallen Graham ◽  
Chad T. Collier ◽  
Joel E. Thurmond ◽  
...  
Keyword(s):  
Drinking Water ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Molecular Ecology ◽  
Distal Colon ◽  
Goblet Cells ◽  
Gi Tract ◽  
Microbial Responses ◽  
Gradient Gel Electrophoresis ◽  
The Impact ◽  
Inorganic Sulfate

There is increasing evidence that hydrogen sulfide (H2S), produced by intestinal sulfate-reducing bacteria (SRB), may be involved in the etiopathogenesis of chronic diseases such as ulcerative colitis and colorectal cancer. The activity of SRB, and thus H2S production, is likely determined by the availability of sulfur-containing compounds in the intestine. However, little is known about the impact of dietary or inorganic sulfate on intestinal sulfate and SRB-derived H2S concentrations. In this study, the effects of short-term (7 day) and long-term (1 year) inorganic sulfate supplementation of the drinking water on gastrointestinal (GI) sulfate and H2S concentrations (and thus activity of resident SRBs), and the density of large intestinal sulfomucin-containing goblet cells, were examined in C3H/HeJBir mice. Additionally, a PCR-denaturing gradient gel electrophoresis (DGGE)-based molecular ecology technique was used to examine the impact of sulfate-amended drinking water on microbial community structure throughout the GI tract. Average H2S concentrations ranged from 0.1 m M (stomach) to 1 m M (cecum). A sulfate reduction assay demonstrated in situ production of H2S throughout the GI tract, confirming the presence of SRB. However, H2S generation and concentrations were greatest in the cecum and colon. Sulfate supplementation of drinking water did not significantly increase intestinal sulfate or H2S concentrations, suggesting that inorganic sulfate is not an important modulator of intestinal H2S concentrations, although it altered the bacterial profiles of the stomach and distal colon of 1-year-old mice. This change in colonic bacterial profiles may reflect a corresponding increase in the density of sulfomucin-containing goblet cells in sulfate-supplemented compared with control mice.

scholarly journals Evaluating the microbial diversity of an in vitro model of the human large intestine by phylogenetic microarray analysis

Microbiology ◽  
2010 ◽  
Vol 156 (11) ◽  
pp. 3270-3281 ◽  
Author(s):  
Mirjana Rajilić-Stojanović ◽  
Annet Maathuis ◽  
Hans G. H. J. Heilig ◽  
Koen Venema ◽  
Willem M. de Vos ◽  
...  
Keyword(s):  
Large Intestine ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Small Subunit ◽  
Ssu Rrna ◽  
Small Subunit Rrna ◽  
Operation Conditions ◽  
Human Large Intestine ◽  
Inoculum Preparation ◽  
The Impact

A high-density phylogenetic microarray targeting small subunit rRNA (SSU rRNA) sequences of over 1000 microbial phylotypes of the human gastrointestinal tract, the HITChip, was used to assess the impact of faecal inoculum preparation and operation conditions on an in vitro model of the human large intestine (TIM-2). This revealed that propagation of mixed faecal donations for the production of standardized inocula has only a limited effect on the microbiota composition, with slight changes observed mainly within the Firmicutes. Adversely, significant shifts in several major groups of intestinal microbiota were observed after inoculation of the in vitro model. Hierarchical cluster analysis was able to show that samples taken throughout the inoculum preparation grouped with microbiota profiles observed for faecal samples of healthy adults. In contrast, the TIM-2 microbiota was distinct. While members of the Bacteroidetes and some groups within the Bacilli were increased in TIM-2 microbiota, a strong reduction in the relative abundance of other microbial groups, including Bifidobacterium spp., Streptococcus spp., and Clostridium clusters IV and XIVa, was observed. The changes detected with the HITChip could be confirmed using denaturing gradient gel electrophoresis (DGGE) of SSU rRNA amplicons.

Pengaruh Konversi Lahan terhadap Strategi Pemanfaatan Modal Nafkah Rumah Tangga Buruh Tani

2020 ◽  
Vol 4 (3) ◽  
pp. 407
Author(s):  
Hesti Prastiwi ◽  
Martua Sihaloho
Keyword(s):  
Qualitative Data ◽  
Rice Fields ◽  
Livelihood Strategies ◽  
Quantitative Approach ◽  
Survey Method ◽  
Land Conversion ◽  
Literature Study ◽  
Irrigated Rice ◽  
Sustainable Food ◽  
The Impact

Lahan merupakan salah satu sumber daya agraria yang sangat penting bagi petani dikarenakan lahan merupakan salah satu sumber untuk bertahan hidup. Sesuai dengan Undang-Undang Dasar Nomor 41 Tahun 2009 tentang Perlindungan Lahan Pertanian Pangan Berkelanjutan. Pembangunan yang terjadi di Indonesia semakin masif, menimbulkan konversi lahan bersifat permanen ketika lahan sawah beririgasi berubah menjadi kawasan pemukiman atau industri. Konversi lahan yang terjadi menyebabkan hilangnya beberapa atau seluruh modal nafkah yang ada. Perubahan modal nafkah ini akan mengakibatkan perubahan strategi nafkah petani. Penelitian ini bertujuan untuk menganalisis dampak konversi lahan terhadap strategi nafkah dan pengaruh pemanfaatan  modal nafkah  terhadap strategi nafkah rumah tangga. Lokasi penelitian ini yaitu Desa Pasirgaok, Kecamatan Rancabungur, Kabupaten Bogor. Metode yang digunakan untuk menggali fakta, data, dan informasi dalam penelitian adalah pendekatan kuantitatif melalui metode survei dengan kuesioner yang didukung oleh data kualitatif melalui wawancara dan studi literatur hingga diperoleh hasil bahwa dampak konversi lahan mempengaruhi modal dan strategi nafkah.Kata Kunci: buruh tani, konversi lahan, modal nafkah, strategi nafkah=====ABSTRACTLand is one of the most important agrarian resources for farmers because land is one source of livelihood survival. According to Constitution Number 41 Year 2009 on concerning The Protection of Sustainable Food Agriculture. The development that is taking place in Indonesia is increasingly massive leading to permanent land conversion when technical irrigated rice fields change into residential or industrial areas. The land conversion that occurs causes a loss of some or all existing livelihood asset. This change in livelihood asset will result in a change in farmers livelihood strategies. This study aims to analyze the influence of the impact of land conversion towards livelihood strategies and the influence of the utilization of livelihood asset towards the livelihood strategies households. The location of this research is Pasirgaok Village, Rancabungur District, Bogor Regency. The method used to extract facts, data, and information in the research is the quantitative approach through survey method with questionnaires supported by qualitative data through interview and literature study until it is obtained that the impact of land conversion towards landless farmer household’s assets and livelihood strategies.Keywords: land conversion, landless farmer, livelihood asset, livelihood strategies

scholarly journals Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

2021 ◽  
Vol 6 (6) ◽  
pp. 79
Author(s):  
Nuno M. M. Ramos ◽  
Joana Maia ◽  
Andrea R. Souza ◽  
Ricardo M. S. F. Almeida ◽  
Luís Silva
Keyword(s):  
Surface Layer ◽  
Surface Temperature ◽  
Near Infrared ◽  
Building Performance ◽  
Colour Difference ◽  
Colour Perception ◽  
Composite Systems ◽  
Solar Reflectance ◽  
Building Cooling ◽  
The Impact

Near-infrared (NIR) reflective materials are being developed for mitigating building cooling needs. Their use contributes to broadening the range of colours, responding to the urban aesthetic demand without compromising the building performance. Despite the increase in NIR reflective pigments investigation, there is still a knowledge gap in their applicability, impact, and durability in multilayer finishing coatings of External Thermal Insulation Composite Systems (ETICS). Hence, the main goal of this work consists of evaluating the impact of incorporating NIR reflective pigments (NRP) in the solar reflectance of the surface layer of ETICS, without affecting the colour perception, as well as their influence on the colour durability and surface temperature. As such, colour, solar reflectance, and surface temperature were monitored for 2 years in dark-coloured specimens of ETICS, with and without NRP and a primer layer. It was confirmed that the main contribution of NRP is the increase of solar reflectance and, consequently, the decrease in surface temperature, especially for high exterior temperatures (around 30 ºC). Moreover, these pigments highly increase the NIR reflectance without affecting the visible colour. In addition, they contribute to maintaining the colour characteristics. The application of primer increased the surface temperature, especially for higher exterior temperatures. However, it contributes to a lower colour difference and solar reflectance variation, which is an important achievement for durability purposes.

scholarly journals Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen

2007 ◽  
Vol 73 (14) ◽  
pp. 4609-4618 ◽  
Author(s):  
Samuel Ohene-Adjei ◽  
Ronald M. Teather ◽  
Michael Ivan ◽  
Robert J. Forster
Keyword(s):  
Phylogenetic Analysis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Methanogenic Archaea ◽  
Type A ◽  
Negative Control ◽  
Rrna Gene ◽  
Association Patterns ◽  
Clone Libraries ◽  
Symbiotic Relationships ◽  
The Impact

ABSTRACT Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.

scholarly journals Impact of Intensive Land-Based Fish Culture in Qingdao, China, on the Bacterial Communities in Surrounding Marine Waters and Sediments

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Qiufen Li ◽  
Yan Zhang ◽  
David Juck ◽  
Nathalie Fortin ◽  
Charles W. Greer
Keyword(s):  
Bacterial Communities ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Fish Culture ◽  
Fish Ponds ◽  
Marine Area ◽  
Gradient Gel Electrophoresis ◽  
Reducing Bacteria ◽  
The Impact ◽  
Nitrate Reducing Bacteria

The impact of intensive land-based fish culture in Qingdao, China, on the bacterial communities in surrounding marine environment was analyzed. Culture-based studies showed that the highest counts of heterotrophic, ammonium-oxidizing, nitrifying, and nitrate-reducing bacteria were found in fish ponds and the effluent channel, with lower counts in the adjacent marine area and the lowest counts in the samples taken from 500 m off the effluent channel. Denaturing gradient gel electrophoresis (DGGE) analysis was used to assess total bacterial diversity. Fewer bands were observed from the samples taken from near the effluent channel compared with more distant sediment samples, suggesting that excess nutrients from the aquaculture facility may be reducing the diversity of bacterial communities in nearby sediments. Phylogenetic analysis of the sequenced DGGE bands indicated that the bacteria community of fish-culture-associated environments was mainly composed of Flavobacteriaceae, gamma- and deltaproteobacteria, including generaGelidibacter, Psychroserpen, Lacinutrix,andCroceimarina.

scholarly journals Differences in Microbial Activity and Microbial Populations of Peat Associated with Suppression of Damping-Off Disease Caused by Pythium sylvaticum

2006 ◽  
Vol 72 (10) ◽  
pp. 6452-6460 ◽  
Author(s):  
Paul J. Hunter ◽  
Geoff M. Petch ◽  
Leo A. Calvo-Bado ◽  
Tim R. Pettitt ◽  
Nick R. Parsons ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Small Subunit ◽  
Disease Suppression ◽  
Rrna Gene ◽  
Damping Off ◽  
Small Subunit Rrna ◽  
Pythium Sylvaticum ◽  
Gradient Gel Electrophoresis ◽  
Microbial Groups

ABSTRACT The microbiological characteristics associated with disease-suppressive peats are unclear. We used a bioassay for Pythium sylvaticum-induced damping-off of cress seedlings to identify conducive and suppressive peats. Microbial activity in unconditioned peats was negatively correlated with the counts of P. sylvaticum at the end of the bioassay. Denaturing gradient gel electrophoresis (DGGE) profiling and clone library analyses of small-subunit rRNA gene sequences from two suppressive and two conducive peats differed in the bacterial profiles generated and the diversity of sequence populations. There were also significant differences between bacterial sequence populations from suppressive and conducive peats. The frequencies of a number of microbial groups, including the Rhizobium-Agrobacterium group (specifically sequences similar to those for the genera Ochrobactrum and Zoogloea) and the Acidobacteria, increased specifically in the suppressive peats, although no single bacterial group was associated with disease suppression. Fungal DGGE profiles varied little over the course of the bioassay; however, two bands associated specifically with suppressive samples were detected. Sequences from these bands corresponded to Basidiomycete yeast genera. Although the DGGE profiles were similar, fungal sequence diversity also increased during the bioassay. Sequences highly similar to those of Cryptococcus increased in relative abundance during the bioassay, particularly in the suppressive samples. This study highlights the importance of using complementary approaches to molecular profiling of complex populations and provides the first report that basidiomycetous yeasts may be associated with the suppression of Pythium-induced diseases in peats.

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