scholarly journals Artificial consortium demonstrates emergent properties of enhanced cellulosic-sugar degradation and biofuel synthesis

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Heejoon Park ◽  
Ayushi Patel ◽  
Kristopher A. Hunt ◽  
Michael A. Henson ◽  
Ross P. Carlson
Keyword(s):  
Biomass Productivity ◽  
Biomass Accumulation ◽  
Vertical Axis ◽  
Feedback Mechanism ◽  
Emergent Properties ◽  
Cellulolytic Enzyme ◽  
E Coli ◽  
Secondary Resource ◽  
Sugar Degradation ◽  
Anoxic Environment

AbstractPlanktonic cultures, of a rationally designed consortium, demonstrated emergent properties that exceeded the sums of monoculture properties, including a >200% increase in cellobiose catabolism, a >100% increase in glycerol catabolism, a >800% increase in ethanol production, and a >120% increase in biomass productivity. The consortium was designed to have a primary and secondary-resource specialist that used crossfeeding with a positive feedback mechanism, division of labor, and nutrient and energy transfer via necromass catabolism. The primary resource specialist was Clostridium phytofermentans (a.k.a. Lachnoclostridium phytofermentans), a cellulolytic, obligate anaerobe. The secondary-resource specialist was Escherichia coli, a versatile, facultative anaerobe, which can ferment glycerol and byproducts of cellobiose catabolism. The consortium also demonstrated emergent properties of enhanced biomass accumulation when grown as biofilms, which created high cell density communities with gradients of species along the vertical axis. Consortium biofilms were robust to oxic perturbations with E. coli consuming O2, creating an anoxic environment for C. phytofermentans. Anoxic/oxic cycling further enhanced biomass productivity of the biofilm consortium, increasing biomass accumulation ~250% over the sum of the monoculture biofilms. Consortium emergent properties were credited to several synergistic mechanisms. E. coli consumed inhibitory byproducts from cellobiose catabolism, driving higher C. phytofermentans growth and higher cellulolytic enzyme production, which in turn provided more substrate for E. coli. E. coli necromass enhanced C. phytofermentans growth while C. phytofermentans necromass aided E. coli growth via the release of peptides and amino acids, respectively. In aggregate, temporal cycling of necromass constituents increased flux of cellulose-derived resources through the consortium. The study establishes a consortia-based, bioprocessing strategy built on naturally occurring interactions for improved conversion of cellulose-derived sugars into bioproducts.

Long-term variability of root production in bioenergy crops from ingrowth core measurements

2021 ◽  
Author(s):  
Cheyenne Lei ◽  
Michael Abraha ◽  
Jiquan Chen ◽  
Yahn-Jauh Su
Keyword(s):  
Land Use ◽  
Biomass Production ◽  
Root Biomass ◽  
Biomass Productivity ◽  
Biomass Accumulation ◽  
Biofuel Production ◽  
Growing Season Length ◽  
Ingrowth Core ◽  
Biofuel Crops

Abstract Aims Long-term determination of root biomass production upon land use conversion to biofuel crops is rare. To assess land-use legacy influences on belowground biomass accumulation, we converted 22-year-old Conservation Reserve Program (CRP) grasslands and 50+-year-old agricultural (AGR) lands to corn (C), switchgrass (Sw) and restored prairie (Pr) biofuel crops. We maintained one CRP grassland as a reference (Ref). We hypothesized that land use history and crop type have significant effects on root density, with perennial crops on CRP grasslands having a higher root biomass productivity, while corn grown on former agricultural lands produce the lowest root biomass. Methods The ingrowth core method was used to determine in situ ingrowth root biomass, alongside measurements of aboveground net primary productivity (ANPP). Ancillary measurements, including air temperature, growing season length, and precipitation were used to examine their influences on root biomass production. Important Findings Root biomass productivity was the highest in unconverted CRP grassland (1716 g m -2 yr -1), and lowest in corn fields (526 g m -2 yr -1). All perennial sites converted from CRP and AGR lands had lower root biomass and ANPP in the first year of planting but peaked in 2011 for switchgrass and a year later for restored prairies. Ecosystem stability was higher in restored prairies (AGR-Pr: 4.3 ± 0.11; CRP-Pr: 4.1 ± 0.10), with all monocultures exhibiting a lower stability. Root biomass production was positively related to ANPP (R  2 = 0.40). Overall, attention should be given to root biomass accumulation in large-scale biofuel production as it is a major source of carbon sequestration.

scholarly journals The effect of CO2 addition and hydraulic retention time on pathogens removal in HRAPs

2020 ◽  
Vol 82 (6) ◽  
pp. 1184-1192
Author(s):  
Graziele Ruas ◽  
Sarah Lacerda Farias ◽  
Priscila G. Scarcelli ◽  
Mayara L. Serejo ◽  
Marc A. Boncz
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Biomass Productivity ◽  
High Rate ◽  
Nitrogen And Phosphorus ◽  
Total Organic Nitrogen ◽  
E Coli ◽  
Bacterial Removal ◽  
Co2 Addition

Abstract The influence of CO2 addition and hydraulic retention time (5 and 7 days) on removal of Pseudomonas aeruginosa, Clostridium perfringens, Staphylococcus sp., Enterococcus sp., and Escherichia coli was evaluated in a system with three parallel 21 L high rate algal ponds. Both the addition of CO2 and an increase in HRT had no significant influence on bacterial removal, but bacterial removal was higher than found in previous studies. The removal was 3.4–3.8, 2.5–3.7, 2.6–3.1, 2.2–2.6 and 1.3–1.7 units log for P. aeruginosa, E. coli, Enterococcus sp., C. perfringens, and for Staphylococcus sp., respectively. Although CO2 addition did not increase disinfection, it did significantly increase biomass productivity (by ≈60%) and settleability (by ≈350%). Additionally, even at the lower 5-day hydraulic retention time, CO2 addition improves removal of chemical oxygen demand (COD), total organic carbon (TOC), total organic nitrogen and phosphorus by 97, 91, 12 and 50%, respectively.

Modeling the Negative Feedback Mechanism in the Enzyme Carboxyltransferase

2011 ◽  
Author(s):  
Xiaoyu Cai ◽  
Marcio de Queiroz ◽  
Glen Meades ◽  
Grover Waldrop
Keyword(s):  
Fatty Acid ◽  
Negative Feedback ◽  
Acid Synthesis ◽  
Feedback Mechanism ◽  
Mass Action ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Mass Action Kinetics ◽  
E Coli ◽  
Negative Feedback Mechanism

The enzyme acetyl-CoA carboxylase catalyzes the first committed step in fatty acid synthesis in all organisms. The E. coli form of the carboxyltransferase subunit was recently found to regulate its own activity and expression by binding its own mRNA. By binding acetyl-CoA or the mRNA encoding its own subunits, Carboxyltransferase is able to sense the metabolic state of the cell and attenuate its own translation and enzymatic activity using a negative feedback mechanism. In this paper, this network of interactions is modeled mathematically using mass action kinetics. Numerical simulations of the model show agreement with experimental results.

scholarly journals The genome of stress tolerant crop wild relative Paspalum vaginatum leads to increased biomass productivity in the crop Zea mays

2021 ◽  
Author(s):  
Guangchao Sun ◽  
Nishikant Wase ◽  
Shengqiang Shu ◽  
Jerry Jenkins ◽  
Bangjun Zhou ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Biomass Productivity ◽  
Biomass Accumulation ◽  
Single Copy ◽  
Crop Wild Relatives ◽  
Metabolic Phenotype ◽  
Grass Species ◽  
Wild Relative ◽  
Crop Wild Relative ◽  
Paspalum Vaginatum

A number of crop wild relatives can tolerate extreme stressed to a degree outside the range observed in their domesticated relatives. However, it is unclear whether or how the molecular mechanisms employed by these species can be translated to domesticated crops. Paspalum (Paspalum vaginatum) is a self-incompatible and multiply stress-tolerant wild relative of maize and sorghum. Here we describe the sequencing and pseudomolecule level assembly of a vegetatively propagated accession of P. vaginatum. Phylogenetic analysis based on 6,151 single-copy syntenic orthologous conserved in 6 related grass species placed paspalum as an outgroup of the maize-sorghum clade demonstrating paspalum as their closest sequenced wild relative. In parallel metabolic experiments, paspalum, but neither maize nor sorghum, exhibited significant increases in trehalose when grown under nutrient-deficit conditions. Inducing trehalose accumulation in maize, imitating the metabolic phenotype of paspalum, resulting in autophagy dependent increases in biomass accumulation.

Molecular cloning of cellulolytic enzyme genes from Cellulomonas flavigena in E. coli

1988 ◽  
Vol 8 (3) ◽  
pp. 249-255 ◽  
Author(s):  
Jesus Silva ◽  
Markku Saloheimo ◽  
Cecilia Montanez ◽  
Jonathan K.C. Knowles ◽  
Tuula T. Teeri
Keyword(s):  
Molecular Cloning ◽  
Cellulolytic Enzyme ◽  
E Coli ◽  
Cellulomonas Flavigena

scholarly journals Competitive resource allocation to metabolic pathways contributes to overflow metabolisms and emergent properties in cross-feeding microbial consortia

2018 ◽  
Vol 46 (2) ◽  
pp. 269-284 ◽  
Author(s):  
Ross P. Carlson ◽  
Ashley E. Beck ◽  
Poonam Phalak ◽  
Matthew W. Fields ◽  
Tomas Gedeon ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Stress Responses ◽  
Biomass Productivity ◽  
Resource Scarcity ◽  
Microbial Consortia ◽  
Emergent Properties ◽  
Overflow Metabolism ◽  
Investment Strategies ◽  
Microbial Stress ◽  
Allocation Strategies

Resource scarcity is a common stress in nature and has a major impact on microbial physiology. This review highlights microbial acclimations to resource scarcity, focusing on resource investment strategies for chemoheterotrophs from the molecular level to the pathway level. Competitive resource allocation strategies often lead to a phenotype known as overflow metabolism; the resulting overflow byproducts can stabilize cooperative interactions in microbial communities and can lead to cross-feeding consortia. These consortia can exhibit emergent properties such as enhanced resource usage and biomass productivity. The literature distilled here draws parallels between in silico and laboratory studies and ties them together with ecological theories to better understand microbial stress responses and mutualistic consortia functioning.

scholarly journals Features of colonization of the phytosphere of wheat seedlings by introduced strains of Escherichia coli

2020 ◽  
Keyword(s):  
Escherichia Coli ◽  
Growth Response ◽  
Linear Growth ◽  
Biomass Accumulation ◽  
Clinical Strain ◽  
Adhesive Properties ◽  
Wheat Seedlings ◽  
E Coli ◽  
Soil Isolate ◽  
Different Parts

The paper presents the results of the study of the ability of introduced Escherichia coli strains to colonize different niches of the phytosphere – the rhizosphere, endosphere, and phylosphere of Mersia winter soft wheat seedlings and to influence the plant growth response under these conditions. The ATCC 8739 and clinical E. coli strains were used as the study material, as well as an isolate from the wheat agrocenosis soil. The vegetation experiments were carried out in the factorial chamber of the Department of Plant Physiology and Biochemistry of Plants and Microorganisms of V.N.Karazin Kharkiv National University. The experimental plants were inoculated with suspensions of E. coli strains and soil isolate by watering them in vegetation vessels where seedlings were grown for 10 days. In parallel by the method of successive washes, we analyzed the dynamics of the number of E. coli CFU in the rhizome, endo- and phyllosphere of seedlings. After completion of the experiment, the growth response was analyzed by linear growth and by the integral index of growth and biosynthetic processes – biomass accumulation. The results of experiments show that inoculation with ATCC 8739 and clinical strains of E. coli reduced the germination of wheat seeds and inhibited the growth response. Inoculation with E. coli soil isolate has virtually no effect on seed germination, linear growth, and biomass accumulation by Mersia seedlings. It was found that the number of E. coli bacteria in the phytosphere of wheat plants depended on the type of inoculated strain and differs in different parts of the seedlings phytosphere. The maximum number of E. coli CFU in the phytosphere was detected at the inoculation of plants with the clinical strain, three times less – at exposure to the soil isolate, almost 6 times less – at the inoculation with the standard strain. Differences in the degree of colonization of different parts of the phytosphere were detected at the inoculation of the test seedlings with different strains and soil isolates of E. coli: in the control variant and under the influence of ATCC 8739, the distribution between the rhizo- and endosphere is approximately the same. When the plants were inoculated with the clinical strain, endosphere was colonized, when using the soil isolate – the rhizosphere. In the phyllosphere of the experimental seedlings, only cells of the clinical strain were found in a small number, which indicates its increased adhesive properties. Plant-microbial relationships and the ability of conditionally pathogenic E. coli bacteria to colonize different areas of the plant organism and to use wheat seedlings as an alternative host are discussed.

scholarly journals Cooperativity of Kv7.4 channels confers ultrafast electromechanical sensitivity and emergent properties in cochlear outer hair cells

2020 ◽  
Vol 6 (15) ◽  
pp. eaba1104 ◽  
Author(s):  
Maria C. Perez-Flores ◽  
Jeong H. Lee ◽  
Seojin Park ◽  
Xiao-Dong Zhang ◽  
Choong-Ryoul Sihn ◽  
...  
Keyword(s):  
Hair Cells ◽  
High Frequency ◽  
Channel Gating ◽  
Ionic Channels ◽  
Feedback Mechanism ◽  
Outer Hair Cells ◽  
Viscous Drag ◽  
Emergent Properties ◽  
Voltage Gated ◽  
Kinetics Of

The mammalian cochlea relies on active electromotility of outer hair cells (OHCs) to resolve sound frequencies. OHCs use ionic channels and somatic electromotility to achieve the process. It is unclear, though, how the kinetics of voltage-gated ionic channels operate to overcome extrinsic viscous drag on OHCs at high frequency. Here, we report ultrafast electromechanical gating of clustered Kv7.4 in OHCs. Increases in kinetics and sensitivity resulting from cooperativity among clustered-Kv7.4 were revealed, using optogenetics strategies. Upon clustering, the half-activation voltage shifted negative, and the speed of activation increased relative to solitary channels. Clustering also rendered Kv7.4 channels mechanically sensitive, confirmed in consolidated Kv7.4 channels at the base of OHCs. Kv7.4 clusters provide OHCs with ultrafast electromechanical channel gating, varying in magnitude and speed along the cochlea axis. Ultrafast Kv7.4 gating provides OHCs with a feedback mechanism that enables the cochlea to overcome viscous drag and resolve sounds at auditory frequencies.

scholarly journals Dual-level autoregulation of the E. coli DeaD RNA helicase via mRNA stability and Rho-dependent transcription termination

2020 ◽  
Author(s):  
Sandeep Ojha ◽  
Chaitanya Jain
Keyword(s):  
Mrna Stability ◽  
Transcription Termination ◽  
Rna Helicase ◽  
Feedback Mechanism ◽  
Helicase Activity ◽  
Coding Region ◽  
E Coli ◽  
Negative Feedback Mechanism ◽  
Dead Box ◽  
Rna Remodeling

ABSTRACTDEAD-box proteins (DBPs) are RNA remodeling factors associated with RNA helicase activity that are found in nearly all organisms. Despite extensive studies on the mechanisms used by DBPs to regulate RNA function, very little is known about how DBPs themselves are regulated. In this work, we have analyzed the expression and regulation of DeaD/CsdA, the largest of the DBPs in Escherichia coli (E. coli). We show that deaD transcription initiates 838 nts upstream of the start of the coding region. We have also found that DeaD is autoregulated through a negative feedback mechanism that operates both at the level of mRNA stability and Rho-dependent transcription termination, and this regulation is dependent upon the 5’ untranslated region (5’ UTR). These findings suggest that DeaD might be regulating the conformation of its own mRNA through its RNA helicase activity to facilitate ribonuclease and Rho access to its 5’UTR.

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

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