scholarly journals Characterization of ApuB, an Extracellular Type II Amylopullulanase from Bifidobacterium breve UCC2003

2008 ◽  
Vol 74 (20) ◽  
pp. 6271-6279 ◽  
Author(s):  
Mary O'Connell Motherway ◽  
Gerald F. Fitzgerald ◽  
Sabine Neirynck ◽  
Sinead Ryan ◽  
Lothar Steidler ◽  
...  
Keyword(s):  
Energy Source ◽  
Physiological Role ◽  
Class Ii ◽  
Type Ii ◽  
Starch Metabolism ◽  
Bifidobacterium Breve ◽  
Knockout Mutation

ABSTRACT The apuB gene of Bifidobacterium breve UCC2003 was shown to encode an extracellular amylopullulanase. ApuB is composed of a distinct N-terminally located α-amylase-containing domain which hydrolyzes α-1,4-glucosidic linkages in starch and related polysaccharides and a C-terminally located pullulanase-containing domain which hydrolyzes α-1,6 linkages in pullulan, allowing the classification of this enzyme as a bifunctional class II pullulanase. A knockout mutation of the apuB gene in B. breve UCC2003 rendered the resulting mutant incapable of growth in medium containing starch, amylopectin, glycogen, or pullulan as the sole carbon and energy source, confirming the crucial physiological role of this gene in starch metabolism.

Role of plasma epinephrine in fasted exercising rats

1985 ◽  
Vol 248 (3) ◽  
pp. R302-R307 ◽  
Author(s):  
W. W. Winder ◽  
M. L. Terry ◽  
V. M. Mitchell
Keyword(s):  
Physiological Role ◽  
Quadriceps Muscle ◽  
Type I ◽  
Type Ii ◽  
Plasma Epinephrine ◽  
Lateral Gastrocnemius ◽  
White Region ◽  
Gastrocnemius Muscles ◽  
Fast Twitch

We have investigated the physiological role of the marked increase in plasma epinephrine that occurs in fasted exercising rats. Fasted adrenodemedullated (ADM) rats show a marked reduction in endurance run times compared with sham-operated (SO) controls. After running for 30 min at 21 m/min up a 10% grade, ADM rats' blood glucose was 2.9 +/- 0.1 mM vs. 4.3 +/- 0.2 mM in SO rats. At the same time, blood lactate was 3.0 +/- 0.2 mM in SO rats compared with 1.0 +/- 0.1 mM in ADM rats. Glycogenolysis was impaired in ADM rats in the fast-twitch white region of the quadriceps, lateral gastrocnemius, and soleus muscles but not in the fast-twitch red region of the quadriceps muscle. Hepatic adenosine 3',-5'-cyclic monophosphate was increased to the same extent in ADM and SO rats during exercise. Infusion of epinephrine into ADM rats during exercise corrected the hypoglycemia, restored lactate to normal, and stimulated glycogenolysis in soleus, white quadriceps, and lateral gastrocnemius muscles. Epinephrine-dependent glycogenolysis in contracting type I and noncontracting type II muscle fibers apparently provides essential quantities of lactate for hepatic gluconeogenesis in fasted exercising rats.

Activated sludge population dynamics

1994 ◽  
Vol 30 (11) ◽  
pp. 159-169 ◽  
Author(s):  
Jiri Wanner
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Organic Pollution ◽  
Paper Briefly ◽  
Microbial Composition ◽  
Selection Mechanisms ◽  
Sludge Settling

The paper briefly surveys topics covered by the IAWQ Specialist Group on Activated Sludge Population Dynamics. The activated sludge population dynamics has been formulated as a branch of water science and technology concerned with phenomena governing the relationships between activated sludge microorganisms and their functions. The characterization of organic pollution fractions in wastewaters according to their rate of biodegradation has been discussed and the role of wastewater as an inoculum stressed. The characterization of activated sludge biomass has been evaluated from two viewpoints: grouping according to metabolic abilities and identification and classification of activated sludge microorganisms. The basic selection mechanisms influencing the microbial composition of activated sludge have been described. The problems with activated sludge settling and thickening properties have been mentioned as a typical example of applied population dynamics research.

scholarly journals Smartphones and Learning: An Extension of M-Learning or a Distinct Area of Inquiry

2022 ◽  
Vol 12 (1) ◽  
pp. 50
Author(s):  
Kendall Hartley ◽  
Alberto Andújar
Keyword(s):  
Future Research ◽  
Unique Role ◽  
Distinct Area ◽  
Unique Nature ◽  
Author Keywords ◽  
Learning Research ◽  
Research In Education

The smartphone has become an integral part of the education landscape. While there has been significant smartphone research in education under the guise of m-learning, the unique role of the device suggests that m-learning may not be an appropriate characterization. The purpose of this paper is to review the use of m-learning as a primary descriptor for smartphone- and learning-related research. In support of this goal, the paper reviews the definitions associated with m-learning, smartphones, and related technologies from the perspective of educational research. In addition, a review of author keywords of research on smartphones in education is used to provide context to the classification of the research. Finally, three theoretically guided smartphone programs are presented as evidence of the unique nature of smartphone and learning research. This review concludes with recommendations for the characterization of future research.

scholarly journals Are Virtual Particles Less Real?

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 141 ◽  
Author(s):  
Gregg Jaeger
Keyword(s):  
Quantum Field ◽  
Interacting Particles ◽  
Virtual Particles ◽  
Quantum Particles ◽  
Action At A Distance ◽  
Relationship Of ◽  
The Relationship

The question of whether virtual quantum particles exist is considered here in light of previous critical analysis and under the assumption that there are particles in the world as described by quantum field theory. The relationship of the classification of particles to quantum-field-theoretic calculations and the diagrammatic aids that are often used in them is clarified. It is pointed out that the distinction between virtual particles and others and, therefore, judgments regarding their reality have been made on basis of these methods rather than on their physical characteristics. As such, it has obscured the question of their existence. It is here argued that the most influential arguments against the existence of virtual particles but not other particles fail because they either are arguments against the existence of particles in general rather than virtual particles per se, or are dependent on the imposition of classical intuitions on quantum systems, or are simply beside the point. Several reasons are then provided for considering virtual particles real, such as their descriptive, explanatory, and predictive value, and a clearer characterization of virtuality—one in terms of intermediate states—that also applies beyond perturbation theory is provided. It is also pointed out that in the role of force mediators, they serve to preclude action-at-a-distance between interacting particles. For these reasons, it is concluded that virtual particles are as real as other quantum particles.

scholarly journals Structural and functional analysis of two di-domain aromatase/cyclases from type II polyketide synthases

2015 ◽  
Vol 112 (50) ◽  
pp. E6844-E6851 ◽  
Author(s):  
Grace Caldara-Festin ◽  
David R. Jackson ◽  
Jesus F. Barajas ◽  
Timothy R. Valentic ◽  
Avinash B. Patel ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Functional Role ◽  
Functional Characterization ◽  
Polyketide Synthases ◽  
Type Ii ◽  
Aromatic Polyketides ◽  
Linear Poly ◽  
Bacterial Type

Aromatic polyketides make up a large class of natural products with diverse bioactivity. During biosynthesis, linear poly-β-ketone intermediates are regiospecifically cyclized, yielding molecules with defined cyclization patterns that are crucial for polyketide bioactivity. The aromatase/cyclases (ARO/CYCs) are responsible for regiospecific cyclization of bacterial polyketides. The two most common cyclization patterns are C7–C12 and C9–C14 cyclizations. We have previously characterized three monodomain ARO/CYCs: ZhuI, TcmN, and WhiE. The last remaining uncharacterized class of ARO/CYCs is the di-domain ARO/CYCs, which catalyze C7–C12 cyclization and/or aromatization. Di-domain ARO/CYCs can further be separated into two subclasses: “nonreducing” ARO/CYCs, which act on nonreduced poly-β-ketones, and “reducing” ARO/CYCs, which act on cyclized C9 reduced poly-β-ketones. For years, the functional role of each domain in cyclization and aromatization for di-domain ARO/CYCs has remained a mystery. Here we present what is to our knowledge the first structural and functional analysis, along with an in-depth comparison, of the nonreducing (StfQ) and reducing (BexL) di-domain ARO/CYCs. This work completes the structural and functional characterization of mono- and di-domain ARO/CYCs in bacterial type II polyketide synthases and lays the groundwork for engineered biosynthesis of new bioactive polyketides.

scholarly journals Strictly co-isogenic C57BL/6J-Prnp−/− mice: A rigorous resource for prion science

2016 ◽  
Vol 213 (3) ◽  
pp. 313-327 ◽  
Author(s):  
Mario Nuvolone ◽  
Mario Hermann ◽  
Silvia Sorce ◽  
Giancarlo Russo ◽  
Cinzia Tiberi ◽  
...  
Keyword(s):  
Laboratory Mouse ◽  
Embryonic Stem ◽  
Physiological Role ◽  
Cellular Prion Protein ◽  
Transmissible Spongiform Encephalopathies ◽  
Phenotypic Characterization ◽  
Spongiform Encephalopathies ◽  
Demyelinating Peripheral Neuropathy

Although its involvement in prion replication and neurotoxicity during transmissible spongiform encephalopathies is undisputed, the physiological role of the cellular prion protein (PrPC) remains enigmatic. A plethora of functions have been ascribed to PrPC based on phenotypes of Prnp−/− mice. However, all currently available Prnp−/− lines were generated in embryonic stem cells from the 129 strain of the laboratory mouse and mostly crossed to non-129 strains. Therefore, Prnp-linked loci polymorphic between 129 and the backcrossing strain resulted in systematic genetic confounders and led to erroneous conclusions. We used TALEN-mediated genome editing in fertilized mouse oocytes to create the Zurich-3 (ZH3) Prnp-ablated allele on a pure C57BL/6J genetic background. Genomic, transcriptional, and phenotypic characterization of PrnpZH3/ZH3 mice failed to identify phenotypes previously described in non–co-isogenic Prnp−/− mice. However, aged PrnpZH3/ZH3 mice developed a chronic demyelinating peripheral neuropathy, confirming the crucial involvement of PrPC in peripheral myelin maintenance. This new line represents a rigorous genetic resource for studying the role of PrPC in physiology and disease.

scholarly journals Discovery and characterization of a novel family of prokaryotic nanocompartments involved in sulfur metabolism

2020 ◽  
Author(s):  
Robert J. Nichols ◽  
Benjamin LaFrance ◽  
Naiya R. Phillips ◽  
Luke M. Oltrogge ◽  
Luis E. Valentin-Alvarado ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Biochemical Characterization ◽  
Sulfur Metabolism ◽  
Physiological Role ◽  
Enzymatic Characterization ◽  
Cysteine Desulfurase ◽  
Future Studies ◽  
Pcc 7942

AbstractProkaryotic nanocompartments, also known as encapsulins, are a recently discovered proteinaceous organelle in prokaryotes that compartmentalize cargo enzymes. While initial studies have begun to elucidate the structure and physiological roles of encapsulins, bioinformatic evidence suggests that a great diversity of encapsulin nanocompartments remains unexplored. Here, we describe a novel encapsulin in the freshwater cyanobacterium Synechococcus elongatus PCC 7942. This nanocompartment is upregulated upon sulfate starvation and encapsulates a cysteine desulfurase enzyme via an N-terminal targeting sequence. Using cryoelectron microscopy, we have determined the structure of the nanocompartment complex to 2.2 Å resolution. Lastly, biochemical characterization of the complex demonstrated that the activity of the cysteine desulfurase is enhanced upon encapsulation. Taken together, our discovery, structural analysis, and enzymatic characterization of this prokaryotic nanocompartment provide a foundation for future studies seeking to understand the physiological role of this encapsulin in various bacteria.

scholarly journals ProMetIS, deep phenotyping of mouse models by combined proteomics and metabolomics analysis

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Alyssa Imbert ◽  
Magali Rompais ◽  
Mohammed Selloum ◽  
Florence Castelli ◽  
Emmanuelle Mouton-Barbosa ◽  
...  
Keyword(s):  
Mouse Models ◽  
Physiological Role ◽  
R Package ◽  
Level Data ◽  
Molecular Information ◽  
Number Of Individuals ◽  
Deep Phenotyping ◽  
Omics Data Integration

AbstractGenes are pleiotropic and getting a better knowledge of their function requires a comprehensive characterization of their mutants. Here, we generated multi-level data combining phenomic, proteomic and metabolomic acquisitions from plasma and liver tissues of two C57BL/6 N mouse models lacking the Lat (linker for activation of T cells) and the Mx2 (MX dynamin-like GTPase 2) genes, respectively. Our dataset consists of 9 assays (1 preclinical, 2 proteomics and 6 metabolomics) generated with a fully non-targeted and standardized approach. The data and processing code are publicly available in the ProMetIS R package to ensure accessibility, interoperability, and reusability. The dataset thus provides unique molecular information about the physiological role of the Lat and Mx2 genes. Furthermore, the protocols described herein can be easily extended to a larger number of individuals and tissues. Finally, this resource will be of great interest to develop new bioinformatic and biostatistic methods for multi-omics data integration.

scholarly journals Role of Dynamic Contrast Enhanced MRI in Characterization of Breast Lesions

2014 ◽  
Vol 4 (1) ◽  
pp. 23-33
Author(s):  
P Issar ◽  
SK Issar
Keyword(s):  
Benign Lesion ◽  
Breast Lesions ◽  
Type I ◽  
Type Ii ◽  
Type Iii ◽  
Dynamic Contrast Enhanced ◽  
Contrast Enhanced ◽  
Malignant Lesions

Purpose: To assess the role of Dynamic contrast enhanced magnetic resonance imaging in characterization of breast lesions and to differentiate benign from malignant lesions on the basis of their morphology and enhancement kinetics. Material and Methods: Sixty patients referred to the department of Radiodiagnosis for breast MRI over a period of twenty months were included. Dynamic contrast enhanced (DCE) Magnetic Resonance Imaging (MRI) was performed to differentiate breast lesions on the basis of morphology and enhancement kinetics. The lesions were classified accordingly into type I (progressive enhancement) Type II (plateau) and Type III (washout) kinetics. Morphology and curves of benign and malignant lesions were compared. Result: fifty one benign lesions were detected in 32 patients and 29 malignant lesions were seen in 22 patients, whereas six patients showed normal MRI. It was found that benign lesion were round or oval in shape with well circumscribed margin and showed homogenous contrast enhancement whereas malignant lesions were irregular with spiculated margin and showed heterogenous contrast enhancement. The distribution curve types of benign lesion were Type I (81.25%-26cases), Type II (18.25%-6cases). For malignant lesions Type I (4.54%-1case), Type II (22.72%-5cases) and Type III (72.72%-16cases). Conclusion: The shape of the time- signal intensity curve were an important criteria in differentiating benign from malignant lesions in dynamic breast MR imaging. A type III time curve is a strong indicator of malignancy and is independent of other criteria. DOI: http://dx.doi.org/10.3126/njr.v4i1.11366 Nepalese Journal of Radiology, Vol.4(1) 2014: 23-33

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