scholarly journals Cyclic-di-GMP regulation promotes survival of a slow-replicating subpopulation of intracellularSalmonellaTyphimurium

2019 ◽  
Vol 116 (13) ◽  
pp. 6335-6340 ◽  
Author(s):  
Erik Petersen ◽  
Erez Mills ◽  
Samuel I. Miller
Keyword(s):  
Enzymatic Activity ◽  
Environmental Conditions ◽  
Second Messengers ◽  
Cellulose Synthase ◽  
Active State ◽  
Macrophage Infection ◽  
Fluorescent Biosensor ◽  
Changing Environments ◽  
Intracellular Environment ◽  
Mediated Reduction

SalmonellaTyphimurium can invade and survive within macrophages where the bacterium encounters a range of host environmental conditions. Like many bacteria,S.Typhimurium rapidly responds to changing environments by the use of second messengers such as cyclic di-GMP (c-di-GMP). Here, we generate a fluorescent biosensor to measure c-di-GMP concentrations in thousands of individual bacteria during macrophage infection and to define the sensor enzymes important to c-di-GMP regulation. Three sensor phosphodiesterases were identified as critical to maintaining low c-di-GMP concentrations generated after initial phagocytosis by macrophages. Maintenance of low c-di-GMP concentrations by these phosphodiesterases was required to promote survival within macrophages and virulence for mice. Attenuation ofS. Typhimurium virulence was due to overproduction of c-di-GMP−regulated cellulose, as deletion of the cellulose synthase machinery restored virulence to a strain lacking enzymatic activity of the three phosphodiesterases. We further identified that the cellulose-mediated reduction in survival was constrained to a slow-replicating persister population ofS.Typhimurium induced within the macrophage intracellular environment. As utilization of glucose has been shown to be required forS.Typhimurium macrophage survival, one possible hypothesis is that this persister population requires the glucose redirected to the synthesis of cellulose to maintain a slow-replicating, metabolically active state.

scholarly journals Semenogelins I and II bind zinc and regulate the activity of prostate-specific antigen

2005 ◽  
Vol 387 (2) ◽  
pp. 447-453 ◽  
Author(s):  
Magnus JONSSON ◽  
Sara LINSE ◽  
Birgitta FROHM ◽  
Åke LUNDWALL ◽  
Johan MALM
Keyword(s):  
Enzymatic Activity ◽  
Dissociation Constant ◽  
Prostate Specific Antigen ◽  
Protease Activity ◽  
Specific Antigen ◽  
Active State ◽  
Chromogenic Substrate ◽  
Nmr Analysis ◽  
High Concentration ◽  
High Affinity

In semen, the gel proteins SgI and SgII (semenogelins I and II) are digested by PSA (prostate-specific antigen), resulting in liquefaction and release of motile spermatozoa. Semen contains a high concentration of Zn2+, which is known to inhibit the protease activity of PSA. We characterized the binding of Zn2+ to SgI and SgII and found evidence that these proteins are involved in regulating the activity of PSA. Intact SgI and SgII and synthetic semenogelin peptides were used in the experiments. Binding of Zn2+ was studied by radioligand blotting, titration with a zinc (II) fluorophore chelator and NMR analysis. A chromogenic substrate was used to measure the enzymatic activity of PSA. SgI and SgII bound Zn2+ with a stoichiometry of at least 10 mol (mol of protein)−1 and with an average dissociation constant of approx. 5 μM per site. Moreover, Zn2+-inhibited PSA was activated by exposure to SgI or SgII. Since both proteins have high affinity for Zn2+ and are the dominating proteins in semen, they probably represent the major Zn2+ binders in semen, one function of which may be to regulate the activity of PSA. The system is self-regulating, and PSA is maintained in an active state by its substrate.

scholarly journals Soil Ecosystems Change With Time

2021 ◽  
Vol 9 ◽  
Author(s):  
Enrique Doblas-Miranda
Keyword(s):  
Living Conditions ◽  
Active State ◽  
Diverse Group ◽  
Cold Night ◽  
Vertical Movements ◽  
Soil Mites ◽  
Changing Environments ◽  
3D Space ◽  
Soil Ecosystems

All the animals living below our feet are not still. They can move (to a lot of places because the soil is a 3D space) and to change (for example, from a cocoon to an active state). Therefore, the same soil below a given piece of field may not contain the same living communities in winter as in summer, or even during a sunny day compared to a cold night. For example, research on soil beetle larvae showed seasonal vertical movements, as the larvae searched for better living conditions. Moreover, the soil varies a lot during its formation, and consequently its inhabitants also change. In the case of oribatids, a minuscule but diverse group of soil mites, scientists observed changes in the community over dozen to hundreds of years! Many studies showed a basic but powerful principle: ecosystems are not still photographs, but instead are constantly changing environments.

METHODOLOGY FOR ASSASSING THE EXPORT READINESS OF SMALL AND MEDIUM ENTERPRISES OF THE RUSSIAN FEDERATION AND ITS APPROBATION

2020 ◽  
Vol 2 (5) ◽  
pp. 77-88
Author(s):  
O. N. VORONKOVA ◽  
◽  
T.N. BARONOVA ◽  
Keyword(s):  
Russian Federation ◽  
Environmental Conditions ◽  
Small And Medium Enterprises ◽  
Domestic Market ◽  
Product Line ◽  
Active State ◽  
State Support ◽  
Foreign Markets ◽  
The Russian Federation ◽  
Medium Enterprises

Favorable environmental conditions associated with the devaluation of the Russian ruble, active state support, reduced demand in the domestic market and the presence of solvent demand in foreign markets, with the orientation of small and medium enterprises to active development (including modernization processes, expansion of production assets, updating the product line and etc.), – form their motivation for the internationalization of activities. At the same time, effective access to foreign markets should be based on a methodology for assessing readiness and developing a strategy for export activities. Accordingly, in the article, the author substantiates the methodology for assessing the export potential for Russian SMEs and gives the results of its testing.

scholarly journals Metabolic acclimation—a key to enhancing photosynthesis in changing environments?

2019 ◽  
Vol 70 (12) ◽  
pp. 3043-3056 ◽  
Author(s):  
Helena A Herrmann ◽  
Jean-Marc Schwartz ◽  
Giles N Johnson
Keyword(s):  
Resource Allocation ◽  
Environmental Conditions ◽  
Temperature Sensor ◽  
In Silico ◽  
Photosynthetic Capacity ◽  
Carbon Partitioning ◽  
Photosynthetic Acclimation ◽  
Metabolic Modelling ◽  
Changing Environments ◽  
In Silico Studies

Abstract Plants adjust their photosynthetic capacity in response to their environment in a way that optimizes their yield and fitness. There is growing evidence that this acclimation is a response to changes in the leaf metabolome, but the extent to which these are linked and how this is optimized remain poorly understood. Using as an example the metabolic perturbations occurring in response to cold, we define the different stages required for acclimation, discuss the evidence for a metabolic temperature sensor, and suggest further work towards designing climate-smart crops. In particular, we discuss how constraint-based and kinetic metabolic modelling approaches can be used to generate targeted hypotheses about relevant pathways, and argue that a stronger integration of experimental and in silico studies will help us to understand the tightly regulated interplay of carbon partitioning and resource allocation required for photosynthetic acclimation to different environmental conditions.

scholarly journals Cold Storage of Two Selections of Soursop (Annona muricataL.) in Nayarit, Mexico

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
José Orlando Jiménez-Zurita ◽  
Rosendo Balois-Morales ◽  
Irán Alia-Tejacal ◽  
Leticia Mónica Sánchez Herrera ◽  
Edgar Iván Jiménez-Ruiz ◽  
...  
Keyword(s):  
Weight Loss ◽  
Enzymatic Activity ◽  
Shelf Life ◽  
Cold Storage ◽  
Environmental Conditions ◽  
Chilling Injury ◽  
Titratable Acidity ◽  
Ripening Process ◽  
Lower Weight ◽  
Postharvest Handling

The maturity of two selections of soursop (G1 and G2) from Nayarit, Mexico, was evaluated under environmental conditions at 22°C and refrigeration at 15°C stored for 6 and 8 days, respectively. Maximum CO2and ethylene values were present on the fifth and sixth day. The fruits exposed at 15°C had a significantly lower weight loss (5%) and showed no chilling injury. The firmness of two selections decreased more than 90%. The concentration of TSS increased to 5.3 to 15°Brix, and the titratable acidity was higher for fruit stored at 22°C. The highest concentration of phenols was recorded on the fourth day of storage at 22°C. The enzymatic activity of PPO was increased from physiological ripening to consumption ripening for both treatments. The two selections stored at 22°C registered the highest level of PME activity at ripeness. Shelf life was increased by up to 8 days (4 days at 15°C plus 4 days at 22°C) without causing chilling injury or alterations in the ripening process of the fruits. No significant differences were observed between the two selections evaluated; postharvest handling was considered to be similar; however, it would be advisable to evaluate other technologies combined with refrigeration.

scholarly journals Cross-species PCR and field studies on Paulownia elongata: A potential bioenergy crop

Bioethanol ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Chhandak Basu ◽  
Nirmal Joshee ◽  
Tigran Gezalian ◽  
Brajesh Nanda Vaidya ◽  
Asada Satidkit ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Plant Cell Wall ◽  
Cellulose Synthase ◽  
Cellulose Synthesis ◽  
Acid Extraction ◽  
Dot Blot ◽  
Carbon Sequestration Potential ◽  
Sequestration Potential ◽  
Cellulose Synthase Gene ◽  
Paulownia Elongata

AbstractPaulownia elongata is a short-rotation fast growing tree and is known for high biomass accumulation and carbon sequestration potential. Optimization of protocols for nucleic acid extraction, PCR, RT-PCR, and other molecular biology techniques are required for better understanding of cellulose synthesis and to assess the potential of Paulownia as a biofuel tree. The main objective of this work was to study a putative cellulose synthase amplicon expression under various environmental conditions and evaluate the potentials of Paulownia as a biofuel tree. Using cross-species PCR an amplicon representative of a putative cellulose synthase gene from Paulownia was identified. This 177-bp long DNA sequence was 46% similar with cellulose synthase genes from Arabidopsis as expected. Gene specific primers for this particular Paulownia cellulose synthase gene were designed and reverse transcription PCR was performed to confirm its transcription. We report an inexpensive cDNA dot-blot method to study expression of this gene under various environmental conditions. We observed that cold and, to a lesser extent, heat stress downregulated its expression. This information will help to understand cellulose deposition in plant cell wall under stressful conditions. To the best of our knowledge this is the first characterization of a cDNA sequence from Paulownia elongata.

On promiscuity, changing environments and the possibility of replaying the molecular tape of life

2012 ◽  
Vol 445 (1) ◽  
pp. e1-e3 ◽  
Author(s):  
Jose M. Sanchez-Ruiz
Keyword(s):  
Sequence Space ◽  
Environmental Conditions ◽  
Protein Sequence ◽  
Significant Extent ◽  
Darwinian Selection ◽  
Changing Environments ◽  
Biochemical Journal ◽  
Living Organisms ◽  
Protein Sequence Space ◽  
Simple Picture

The consequences for organism fitness of mutations in a given protein are often thought to be determined to a significant extent by epistasis, that is, by the fact that the effect of a mutation may be strongly dependent on the previous mutational background. Actually, a given mutation could be deleterious or beneficial depending on the background, a situation known as ‘sign epistasis’. Under pervasive sign epistasis, many mutational trajectories towards a ‘fitter protein’ will show a ‘dip’ in fitness and, it has been previously suggested, only a few trajectories will be available to Darwinian selection. In this issue of the Biochemical Journal, Zhang et al. explore how this simple picture needs to be modified when two rather general and important features are taken into account, namely that many proteins are promiscuous and that living organisms must survive and thrive in environments that change continuously. The multidimensional nature of epistasis for a protein involved in several tasks, together with the fact that different tasks may become critical for organism survival as environmental conditions change, is shown by Zhang et al. to contribute to eliminating fitness dead-ends in protein sequence space. Consequently, many alternative mutational trajectories should allow protein optimization for enhanced organism fitness under changing environmental conditions.

scholarly journals Individual Variation in Glucocorticoid Plasticity: Considerations and Future Directions

2020 ◽  
Vol 60 (1) ◽  
pp. 79-88
Author(s):  
Sarah Guindre-Parker
Keyword(s):  
Empirical Research ◽  
Hpa Axis ◽  
Environmental Conditions ◽  
Individual Variation ◽  
Endocrine System ◽  
Metabolic Demand ◽  
Future Directions ◽  
Changing Environments ◽  
Multiple Phenotypes ◽  
Future Work

Abstract The hypothalamic–pituitary–adrenal (HPA) axis regulates the secretion of glucocorticoids, hormones with diverse roles ranging from regulating daily metabolic demand to coping with sudden perturbations. As a result, glucocorticoids are thought to help vertebrates track their changing environments and coordinate plasticity in diverse phenotypes. While this endocrine system is highly plastic—where one individual can produce multiple phenotypes across varying environmental conditions—little is understood about the degree to which individuals, populations, or species differ in circulating glucocorticoid plasticity. Empirical research quantifying individual variation in glucocorticoid plasticity has increased in recent years, though the multiple complex roles of the HPA-axis make it challenging to generalize the extent to which individual variation in plasticity exists. I provide an overview of current findings on variation in glucocorticoids plasticity, and outline multiple types of glucocorticoid plasticity researchers should consider in future work to advance our understanding of the causes and consequences of individual variation in glucocorticoid plasticity.

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