Microbial biomass

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Effect of organic and mineral amendments upon soil respiration and microbial biomass in a saline-sodic soil

Effect of organic and mineral amendments upon soil respiration and microbial biomass in a saline-sodic soil

J.E. Celis, M. Sandoval, B. Martínez, and C. Quezada. 2013. Effect of organic and mineral amendments upon soil respiration and microbial biomass in a saline-sodic soil. Cien. Inv. Agr. 40(3): 571-580. An understanding of soil carbon stocks and fluxes in saline-sodic soils is becoming critical in environmental management because salinity and sodicity are predicted to increase worldwide. The effects of amendment with sewage sludge (SW), mined gypsum (MG) and synthetic gypsum (SG) on the soil respiration rate and soil (S) microbial biomass (SMB) of a saline-sodic soil were assessed in vitro over 60 days under controlled conditions. The treatments were: T1 = S + MG (7 t ha -1 ); T2 = S + MG (7 t ha -1 ) + SW (90 t ha -1 ); T3 =

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Microbial biomass as an antioxidant for tilapia feed

Microbial biomass as an antioxidant for tilapia feed

Neutrophils and macrophages are phagocytic cells that generate unpaired oxygen molecules (free radicals) in the presence of anti- gens (D€ ugenci, Arda, & Candan, 2003), causing increases in the NBT measurement. In our study, none of the treatments implied a challenge (no antigens); however, NBT levels in MB tilapia were lower than in control, indicating either that the production of free radicals was decreased or that the antioxidant effect of the bio- masses neutralized the free radicals produced by the leucocytes (reducing oxygen radicals and nitrous oxide). So, it is feasible to say that the carotenoids in Rubrivivax and Spirulina (Jaime-Ceballos et al., 2006; Ponsano et al., 2008) and the vitamins in Saccha- romyces (Ran et al., 2015) neutralized the free radicals responsible for the reduction in NBT into formazan granules. Free radicals are toxic to microorganisms and host cells because their action is usu- ally unspecific; therefore, they need to be controlled or neutralized in the absence of antigens to protect host cells. Gallani, Vallad ~ ao, Ponsano, and Pilarski (2017) reported a decreased respiratory activ- ity of leucocytes in pacus (Piaractus mesopotamicus) fed R. gelati- nosus biomass. According to Sakai (1999), several components of microorganisms have immunomodulatory activity, which influence the leucocyte respiratory burst. Some authors found enhancement effects on the nonspecific immune response of tilapia fed yeast nucleotides (Xu et al., 2015) and yeast culture (Ran et al., 2015; Zhou et al., 2009).

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Biosorption of heavy metals by use of microbial biomass

Biosorption of heavy metals by use of microbial biomass

ABSTRACT. Microorganisms are known to remove heavy metal ions from water and their utilization as biosorbents for heavy metal removal, offers a potential alternative to the existent methods for the detoxifi- cation and recovery of toxic/precious metals present in industrial wastewater. Many yeasts, fungi, algae, bacteria and some aquatic plants have the capacity to concentrate metals from aqueous diluted solutions, and to accumulate them inside the cell structure. To date, the most successful biotechnological processes utilize biosorption and bioprecipitation, but other processes such as binding by specific macromolecules may have future potential. Technologies using these processes are currently used to control pollution from diverse sources. In this article, the term biosorption is used to encompass uptake by whole biomass (living or dead) via physico-chemical mechanisms such as adsorption or ion exchange. Where living biomass is used, metabolic uptake mechanisms may also contribute to the process. Mention is made about systems that employ a mixture of microorganisms as well as higher plants.

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TítuloModeling of biomass accumulation and filter bed st6ructure change in biofilters for gaseous toluene removal

TítuloModeling of biomass accumulation and filter bed st6ructure change in biofilters for gaseous toluene removal

In this study, a proper microbial growth model was established and analyzed to investigate the biomass accumulation process in biofilters. Four biofilters treating gaseous toluene were set up in parallel and were operated under different inlet toluene loadings for 100 days. Based on the experimental data of microbial biomass and toluene removal rate, the kinetic parameters were decided by either estimation from literature or parameter regression. The calculation results based on the model showed a good agreement with the experimental data of biomass change. By applying the model, it is found that lower than 50% of biomass in the filter bed was active during the last 50 days for the four biofilters. In addition, the void fraction of the filter bed with highest loading was only 55% of the initial level at the end of the operation. All the experimental and calculation results indicated that the microbial growth model could successfully describe the biomass accumulation process and have the potential to predict the long-term performance of biofilters.

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Functional convergence of microbes associated with temperate marine sponges

Functional convergence of microbes associated with temperate marine sponges

Most of our current knowledge about the microbes associated with marine sponges is based on 16S rRNA gene library construction, functional gene surveys and metagenomics, which are used to infer alternative meta- bolic routes for sponge metabolism. These metabolic routes include a variety of processes with alternative energy (photo- or chemotrophic) and carbon (hetero- or autotrophic) sources under different oxygen conditions (see Hoffmann et al., 2005; 2009; Hentschel et al., 2006; Taylor et al., 2007). An outcome of each of these pro- cesses is the growth of microbial biomass in the consor- tium, but the adaptive value of these processes to the host sponge and/or the consortium is not well understood. Moreover, while a phylogenetically and physiologically diverse array of microbes associate with sponges, their roles in nutrient cycles remains largely unknown (Hentschel et al., 2006; Taylor et al., 2007; Moya et al., 2008; Hoffmann et al., 2009).

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Nitrogen limitation and microbial diversity at the treeline

Nitrogen limitation and microbial diversity at the treeline

Total microbial biomass (bacteria, protozoa and fungi) did not vary signifi cantly across vegetation belts encom- passing the treeline when sampling occurred (Fig. 3a). Despite such constant biomass, fungal community compo- sition did change along the elevational gradient and concomitant changes in vegetation types as hypothesised (Table 3). Th ese results confi rm recent fi ndings from a montane elevational gradient in eastern Peru (Fierer et al. 2011) according to which the composition of microbial community changes with elevation even though microbial diversity is independent of altitude. Although not in the context of the treeline, the infl uence of elevation on soil fungal communities has also been recently observed in the case of Silene acaulis cushions (Roy et al. 2013). By contrast to fungal communities, bacterial communities did not diff er along the elevational gradient (Table 3). According to recent results, bacterial and fungal communi- ties have diff erent responses to local site characteristics, with bacteria being primarily infl uenced by soil pH (Fierer and Jackson 2006, Roy et al. 2013) while fungi respond mainly to plant-related variables, such as soil organic matter quality or annual radiation (Zinger et al 2011). Th us, at our study site, the consistency of soil pH among the three vegetation types could explain the con- stant bacterial community composition at the treeline (Fig. 2). By contrast, the change in fungal community composition could be linked to the decrease in the soil C:N ratio along the vegetation gradient towards the treeline (i.e. from bet to alp, Fig. 2). Furthermore, soil C:N was strongly correlated to the fungi:bacteria ratio (Table 4) across all vegetation belts with fungi dominating over bacteria in soils with high C:N ratio regardless of the vegetation belt. By contrast, bacterial biomass was correlated to the amount in total dissolved nitrogen (TDN, Table 4), mainly N-NH 4 ⫹ , which tended to be higher at lower elevation in

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ENTOMOPATÓGENOS UTILIZADOS EN CONTROL  MICROBIAL DE INSECTOS PLAGA./

ENTOMOPATÓGENOS UTILIZADOS EN CONTROL MICROBIAL DE INSECTOS PLAGA./

Nomurea rileyi, constituye un insecticida microbial muy popular el cual ha sido estudiado detalladamente en estados del Sureste de USA, para el control de la oruga terciopelo del frijol (Anticarsia gemmatalis), el gusano medidor de la soya (larva de una alevilla de la familia Geometridae). Ignoffo y colaboradores (1976b), indican que el suelo es provablemente el reservorio de conidias que inician anualmente epizootias de N. rileyi sobre Lepidópteros. Este hongo en temperaturas y humedades relativamente bajas, puede producir tres tipos de estructuras de resistencia morfológicamente distintas; estructuras intrahifales de doble pared celular, clamidiosporas y cuerpos de reposo con grandes cantidades de lípidos localizados en la cavidad del cuerpo del insecto (Figura 20), en donde sobreviven mientras las condiciones ambientales son propicias para una nueva epizootia (Mc Coy et. al., 1988; McClintic, 1995; CB-09, 1999).

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Patogenia microbiana: Conceptos bsicos en la interaccin hospedero microorganismo

Patogenia microbiana: Conceptos bsicos en la interaccin hospedero microorganismo

To originate an infection, bacteria, viruses, fungi, and parasites use several strategies. A common mech- anism used by these microorganisms is the microbial adherence, representing one of the crucial steps of an infection involving a direct interaction between microorganism and host surfaces. That interaction is mediated by microbe structures binding specifi cally to ligands on the host cells. Structures that mediate the microorganism adhesion are called adhesins, while in the host the cellular ligand is called receptor. 15

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Metagenomic analysis of fungal diversity of marine sediments from the Gulf of MexicoAnálisis metagenómico de la diversidad fúngica en sedimentos marinos del Golfo de México

Metagenomic analysis of fungal diversity of marine sediments from the Gulf of MexicoAnálisis metagenómico de la diversidad fúngica en sedimentos marinos del Golfo de México

Fungal communities play multiple key roles in the ecosystem. They represent the majority of biomass on soils, decompose organic material, providing nutrients to plants, and act as biomarkers of the ecosystem health (Borneman and Hartin, 2000). Despite the current knowledge on the existing fungal species, most of them remain uncharacterized; in the last two decades, a conservative number of ~1.5 million fungal species had been estimated (Hawksworth and Rossman, 1997). The estimation of the Earth’s fungal richness depends mostly in the different extrapolation techniques. While some recent studies estimate at least 6 million species, considering the fungus to plant ratio (17:1) (Taylor et al., 2014), others remains more cautious and estimate between 2.2 to 3.8 million fungal species by taking into account fungus to plant ratios, and also species discovery and molecular sequence data (Hawksworth and Lucking, 2017). These studies highlight the lack of knowledge and disparity between estimations on the real fungal diversity on Earth, a problem that arises from the lack of an ideal method that allows identifying the undescribed fungal species and from the vast amount of environments that remain to be sampled. In addition, there are no realistic estimates that include fungi associated with animals or fungi from freshwater and marine environments (Richards et al., 2012).

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Comparative study of bacterial and fungal alpha amylase industrial producers

Comparative study of bacterial and fungal alpha amylase industrial producers

Currently, industrial enzymes are commonly manufactured from microorganisms. They are the preferred source of industrial enzymes owing to their economic and technical advantages; reduced processing time, low energy input, cost effectiveness, fast growth rate, nontoxic and eco-friendly characteristics (J.Charnock Simon, 2005; Leisola et al., 2009). In addition, microbial enzymes are more active and stable than plant and animal enzymes (Anbu et al., 2013). Natural selection, recombinant DNA technologies and classical improvement techniques are used to improve the microorganisms. Genetic modification of production microorganisms is practiced to enhance their productivity and adapt the microorganisms to industrial fermentation conditions. Because all of that, a limited number of microorganisms are considered to be appropriate producers. Such organisms must be recognized as safe (GRAS), well characterized, non-toxigenic and non-pathogenic (Hatti-kaul, 2009) .

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Flora microbial y fisiología reproductiva en el puerperio de los bovinos

Flora microbial y fisiología reproductiva en el puerperio de los bovinos

por e l cuerpo luteo p a r a e l mantenimiento d e la p r e ñ e z , sostie- ne niveles elevados en la s a n g r e , lo que no solamente favorece e l medio p a r a la multiplicación microbial, sino que baja l a s defensas, promueve la infección y r e t a r d a e l crecimiento d e l folículo, s e inhibe l a salida de loquios por falta de tono m u s - cular y e l r e g r e s o d e l t r a c t o genital a su completa normalidad e s muy tardía.

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Effects of different poultry manure fertilization levels and cutting times on Moringa oleifera production

Effects of different poultry manure fertilization levels and cutting times on Moringa oleifera production

In the present study, the biomass of the whole plants, leaves and stems increased with the level of fertilization up to a threshold beyond which it began to decrease. The yield reduction observed following this fertilization threshold agrees with observations by Limani and De Vienne (2001), Tendonkeng et al. (2011), who showed that N intake at a rate higher than the potential growth needs of the plant do not increase the forage yield because the N becomes toxic to the plant. This maximum level of fertilization was found to be 200 kg N ha -1 in our study. In addition, Maurice

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Microbial biodiversity: A new voyage of discovery

Microbial biodiversity: A new voyage of discovery

By the same time Carl Woese was sorting out his tree of life, his col- league Norman Pace proposed the use of modern molecular techniques to gain knowledge of the microbial diversity in natural environments. His rationale was based on the fact that with the sequence-based taxonomic cri- terion, a sole gene sequence suffices to ascribe an organism to a known phylum or to define a new one. Ribosomal RNA genes from uncultivated micro-organisms can be obtained directly from environmental samples by amplification with the polymerase chain reaction (PCR). Due to the rela- tively high conservation of rRNA genes, primers can be designed in such a way that they will anneal to sequences that are shared by representatives of all three domains. The fragments thus obtained are resolved by cloning and then sequenced. This approach has proven highly successful, leading to the identification of about 26 new phyla that contain no known cultivated rep- resentatives. These are found in a variety of habitats and some are highly abundant, especially in the previously unexplored Earth’s crust. Most of the latter rely on energy provided by redox reactions of inorganic compounds, as opposed to those that depend either on the harvesting of sunlight or on the metabolism of organic compounds as sources of energy. Most often, the new lineages are distantly related to previously characterized ones and the shape of the tree reveals that bacterial diversity arose as a result of a radia- tion of lineages rather than from a sequential divergence from a main line.

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Assessing microbial safety of drinking water

Assessing microbial safety of drinking water

While the use of (thermotolerant) coliforms and enterococci as indices of faecal pollution has proved successful in preventing the spread of waterborne cholera and typhoid, in the 1960s a new challenge to public health was identified. It was increasingly recognised that enteric viruses, such as hepatitis A and other enteroviruses, could also be transmitted through drinking water (Anon, 1999). Viral contamination of water also originates from pollution with human excreta, but the nature of viruses is very different from that of bacteria. They are much smaller and therefore less likely to be removed during filtration or soil passage and their resistance to disinfection is typically greater. The occurrence of outbreaks of viral illnesses associated with drinking water meeting the coliform standards indicated that coliforms were an inadequate parameter to assess the virological quality of treated drinking water (Berg and Metcalf, 1978; Petrilli et al., 1974; Melnick and Gerba, 1982). Water microbiologists sought suitable alternative microbial parameters and found several groups of viruses that infect bacteria, known as bacteriophages (phages), which have a similar size and also structure characteristics to human pathogenic viruses. These were suggested as being appropriate models for the potential presence of viruses and for their survival and behaviour in the environment, as well as their removal and inactivation by water treatment and disinfection processes (Grabow et al., 1984; Havelaar et al. 1993).

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Efecto de diferentes sustratos en el crecimiento de plántulas de Dasylirion acrotrichum (Schiede) Zucc.

Efecto de diferentes sustratos en el crecimiento de plántulas de Dasylirion acrotrichum (Schiede) Zucc.

Dasylirion acrotrichum is a species used primarily as a religious ornament and is beginning to be exploited by the liquor industry in Oaxaca. Despite this, there is no technical or scientific study of the species, so it is imperative to generate knowledge of it. Therefore, the effect of three different substrates on the growth of D. acrotrichum seedlings was evaluated. The trial was established within the greenhouse belonging to Universidad Autónoma del Estado de Hidalgo. The seeds were germinated and transplanted to polyethylene containers with three different treatments: agricultural land-tezontle (2:1), agricultural land (100 %) and agricultural land-tezontle (1:1). The variables studied were: root biomass, aerial, total and number of leaves. Two measurements were made at 6 and 18 months after the transplant and the data obtained were subjected to a variance analysis. At 6 months, the treatment of agricultural land-tezontle (1:1) had the highest root biomass and total biomass surpassing the other treatments by up to 31.94 % and 23.75 %, respectively. At 18 months, the treatment of agricultural land-tezontle (1:1), reaches the highest aerial and total biomass, surpassing in up to 25.5 % and 24.6 % respectively to the rest of the treatments. Therefore, it is inferred that this substrate improves the initial growth in this species.

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Methanogenic and Sulfate-Reducing Activities in a Hypersaline Microbial Mat and Associated Microbial Diversity

Methanogenic and Sulfate-Reducing Activities in a Hypersaline Microbial Mat and Associated Microbial Diversity

microcosm experiments of hypersaline microbial mats (Fig. 1). These results agree with previous reports on methane production in hypersaline environments in the Napoli mud volcano [32], in microbial mats from Baja California Sur, Mexico [14], and in the Orca Basin, Gulf of Mexico [61]. Furthermore, with the addition of methylated substrates, methane production occurred both in the absence and in the presence of sulfate. Similar results have been recorded in incubations under natural conditions as well as with modified hypersaline microbial mats from Baja California Sur, Mexico [3, 14]. In contrast, experimental control without external substrate supply did not produce methane. In this sense, stable isotope measurements of produced methane in hypersaline environments have suggested that methanogens are operating under conditions of substrate limitation, and when higher concentrations of substrate are added to samples, methanogenesis is further stimulated [20, 21]. These

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Biomass energy. Olive stone

Biomass energy. Olive stone

Let’s go to put ourselves in the place of our company situation. New company start-ups. No one knows us. Our product is relatively new, though (come see below) some companies already sell it, but the majority do not export it. There is a company (as we can see in the section competitors), “Garcia Munte GME”. This company export many products, one of them is biomass. The true is that it is an established company in the market for many years, as specialist in solid fuels, but this company is not specialist in biomass. So, what we can do to face all the weaknesses and threats is:

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Biological and other soil parameters response to winter cover crops in a mediterranean irrigated system

Biological and other soil parameters response to winter cover crops in a mediterranean irrigated system

using the most-probable-number, with forage oats being the most effective. The effect of CC on AMF spores has been less studied, and the results are not homogenous. We found that barley increased the number of spores by 42-72%, but vetch was similar to fallow. This result differs from Galvez et al. (1995), who found that vetch had more spores number relative to fallow and from Boswell et al. (1998), who did not report differences between CC and fallow. The heterogeneity in the results may be due to the methodology. The process of spore count under a microscope may include nonviable spores, either because they are parasitized, old, broken or thick-walled (Walley and Germida, 1995), which may give rise to an overcount. In addition there are AMF spores too small to be reliable extracted by wet sieving, so this method would generate a measurement error that should be taken into consideration. Furthermore, differences in spore number may be due to the variety in the sampling dates among studies, environmental conditions during the experiment or crop dependence on mycorrhizal which influence on the sporulation and spore germination (Declerck et al., 2001; Plenchette et al., 1983). Finally, we remark the different pattern for barley and vetch in both sunflower and maize crops in which the benefits to barley on AMF were larger compared to vetch. Higo et al. (2015) compared in a pot experiment the performance of four potential CC (two legumes and two grasses) and found higher values of AMF colonization in the roots of barley compared with hairy vetch. They attributed these differences to host selectivity. The higher root colonization in barley during the CC season along with its greater root biomass may have enhanced propagule generation (Higo et al., 2013), favoring a greater infection in the subsequent crop.

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MICROBIAL INACTIVATION BY ULTRASOUND

MICROBIAL INACTIVATION BY ULTRASOUND

The microbial inactivation effect of ultrasound is known since the early 30’s [6]. Since then, several investigations have been carried out to study the inactivation effect of ultrasound [7, 8], and ultrasound combined with other agents [9, 10]. At the early 70’s, it was observed that heat sensitivity of spores increased with a previous ultrasonic treatment [11]. Subsequently, it was demonstrated that a simultaneous heat and ultrasound treatment (thermoultrasonication) had a higher lethal effect than a heat treatment at the same temperature [12]. At the early 90’s, the Food Technology group of the University of Zaragoza designed an equipment called Mano-Thermo- Sonicator. With this equipment, the microbial inactivation effect of ultrasound and its combination with pressure (Mano-Sonication; MS) or with pressure and heating (Mano-Thermo-Sonication; MTS) was investigated.

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Quantitative microbial risk assessment

Quantitative microbial risk assessment

• Definition of microbial inactivation: Inactivation studies must select a criterion to define when a microorganism is damaged beyond recovery to an infectious state. Typically, loss of infectivity or culturability is the criterion for quantifying microbial inactivation. Possible additional criteria are usually based on the method to detect cell viability and include changes in electrical conductivity of cells, changes in the permeability of the cell membranes, presence of cell or enzyme activity, changes in the rate of metabolism and changes in the ability of the cell to stain with various dyes. For viruses, this can be integrity of the capsid and/or the nucleic acid. For protozoa, the ability to excyst (viability) has also been used. The most frequently used criterion for culturable organisms (most bacteria, several viruses, some protozoa) is complete loss of reproductive power. Some studies have explored the use of molecular methods to identify pathogen inactivation (Li et al., 2002; Shin & Sobsey, 2008; Lim, Kim & Ko, 2010). This approach relies on the assumption that genetic material is destroyed on pathogen inactivation and cannot be replicated during PCR. In reality, pathogens may be inactivated before genetic material is destroyed, and fragments of genes may be amplified during PCR. Therefore, molecular methods still typically overestimate infectious organism concentration and therefore underestimate microbial inactivation in comparison with cultural methods. However, active or viable but non-culturable (VBNC) states exist, meaning that pathogens may be infectious, yet not culturable (Lothigius et al., 2010). This VBNC state is also true for FIO (Sobsey et al., 1998; Juhna et al., 2007). Pathogen death or inactivation can also be investigated using infectivity studies (e.g. hepatitis A virus and murine norovirus) (Wei et al., 2010).

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