scholarly journals Stability of Intracellular Protein Concentration under Extreme Osmotic Challenge

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3532
Author(s):  
Jordan E. Hollembeak ◽  
Michael A. Model

Cell volume (CV) regulation is typically studied in short-term experiments to avoid complications resulting from cell growth and division. By combining quantitative phase imaging (by transport-of-intensity equation) with CV measurements (by the exclusion of an external absorbing dye), we were able to monitor the intracellular protein concentration (PC) in HeLa and 3T3 cells for up to 48 h. Long-term PC remained stable in solutions with osmolarities ranging from one-third to almost twice the normal. When cells were subjected to extreme hypoosmolarity (one-quarter of normal), their PC did not decrease as one might expect, but increased; a similar dehydration response was observed at high concentrations of ionophore gramicidin. Highly dilute media, or even moderately dilute in the presence of cytochalasin, caused segregation of water into large protein-free vacuoles, while the surrounding cytoplasm remained at normal density. These results suggest that: (1) dehydration is a standard cellular response to severe stress; (2) the cytoplasm resists prolonged dilution. In an attempt to investigate the mechanism behind the homeostasis of PC, we tested the inhibitors of the protein kinase complex mTOR and the volume-regulated anion channels (VRAC). The initial results did not fully elucidate whether these elements are directly involved in PC maintenance.

Author(s):  
سعيد مزعل موازي ◽  
يحيى فائق حسين ◽  
عبد المنعم دولاني ◽  
سيف يوسف عبدالله السويدي

Recently, many studies have been conducted to discover or improve cancers treatment. The current study aims to investigate the anticancer effect of thymoquinone, cordyceps, spirulina, ganoderma lucidium, poria cocos, and lion’s mane in four different concentrations 4, 8, 16, and 32 ug (equivalent to 1 mg/mL) in two different time treatments (48 and 96 hours) on human nasal epithelial cell line RPMI 2650. By using cell culture cytotoxicity techniques and assay, the highest anticancer effect on RPMI 2650 was obtained by thymoquinone. The lowest anticancer effect was demonstrated by poria cocos and cordyceps. However, these two medications showed higher anticancer effect when given in short-term treatment (48 hours) compared to long-term treatment (96 hours). Ganoderma lucidium and spirulina showed better impact than poria cocos, cordyceps, and lion’s mane in term of cells cytotoxicity. Mild to moderate antineoplastic effect was seen by utilizing lion’s mane treatment compared other drugs. Therefore, adopting a long-term treatment of high concentrations and doses of thymoquinone, cordyceps, spirulina, ganoderma lucidium, poria cocos, and lion’s mane can be more effective in the treatment of nasal cancer. In conclusion, these drugs were found to be a promising cancer remedy; therefore, they can be utilized as alternative treatment for nasal cancer or any other type of cancer therapy.


2021 ◽  
Vol 9 (2) ◽  
pp. 189
Author(s):  
Hyeonji Bae ◽  
Dabin Lee ◽  
Jae Joong Kang ◽  
Jae Hyung Lee ◽  
Naeun Jo ◽  
...  

The cellular macromolecular contents and energy value of phytoplankton as primary food source determine the growth of higher trophic levels, affecting the balance and sustainability of oceanic food webs. Especially, proteins are more directly linked with basic functions of phytoplankton biosynthesis and cell division and transferred through the food chains. In recent years, the East/Japan Sea (EJS) has been changed dramatically in environmental conditions, such as physical and chemical characteristics, as well as biological properties. Therefore, developing an algorithm to estimate the protein concentration of phytoplankton and monitor their spatiotemporal variations on a broad scale would be invaluable. To derive the protein concentration of phytoplankton in EJS, the new regional algorithm was developed by using multiple linear regression analyses based on field-measured data which were obtained from 2012 to 2018 in the southwestern EJS. The major factors for the protein concentration were identified as chlorophyll-a (Chl-a) and sea surface nitrate (SSN) in the southwestern EJS. The coefficient of determination (r2) between field-measured and algorithm-derived protein concentrations was 0.55, which is rather low but reliable. The satellite-derived estimation generally follows the 1:1 line with the field-measured data, with Pearson’s correlation coefficient, which was 0.40 (p-value < 0.01, n = 135). No remarkable trend in the long-term annual protein concentration of phytoplankton was found in the study area during our observation period. However, some seasonal difference was observed in winter protein concentration between the 2003–2005 and 2017–2019 periods. The algorithm is developed for the regional East/Japan Sea (EJS) and could contribute to long-term monitoring for climate-associated ecosystem changes. For a better understanding of spatiotemporal variation in the protein concentration of phytoplankton in the EJS, this algorithm should be further improved with continuous field surveys.


Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 177
Author(s):  
Iliya Gritsenko ◽  
Michael Kovalev ◽  
George Krasin ◽  
Matvey Konoplyov ◽  
Nikita Stsepuro

Recently the transport-of-intensity equation as a phase imaging method turned out as an effective microscopy method that does not require the use of high-resolution optical systems and a priori information about the object. In this paper we propose a mathematical model that adapts the transport-of-intensity equation for the purpose of wavefront sensing of the given light wave. The analysis of the influence of the longitudinal displacement z and the step between intensity distributions measurements on the error in determining the wavefront radius of curvature of a spherical wave is carried out. The proposed method is compared with the traditional Shack–Hartmann method and the method based on computer-generated Fourier holograms. Numerical simulation showed that the proposed method allows measurement of the wavefront radius of curvature with radius of 40 mm and with accuracy of ~200 μm.


Author(s):  
M. Focker ◽  
H. J. van der Fels-Klerx ◽  
A. G. J. M. Oude Lansink

AbstractEarly 2013, high concentrations of aflatoxin M1 were found in the bulk milk of a few dairy farms in the Netherlands. These high concentrations were caused by aflatoxin B1 contaminated maize from Eastern Europe that was processed into compound feed, which was fed to dairy cows. Since the contamination was discovered in the downstream stages of the supply chain, multiple countries and parties were involved and recalls of the feed were necessary, resulting into financial losses. The aim of this study was to estimate the direct short-term financial losses related to the 2013 aflatoxin incident for the maize traders, the feed industry, and the dairy sector in the Netherlands. First, the sequence of events of the incident was retrieved. Then, a Monte Carlo simulation model was built to combine the scarce and uncertain data to estimate the direct financial losses for each stakeholder. The estimated total direct financial losses of this incident were estimated to be between 12 and 25 million euros. The largest share, about 60%, of the total losses was endured by the maize traders. About 39% of the total losses were for the feed industry, and less than 1% of the total losses were for the dairy sector. The financial losses estimated in this study should be interpreted cautiously due to limitations associated with the quality of the data used. Furthermore, this incident led to indirect long-term financial effects, identified but not estimated in this study.


2019 ◽  
Author(s):  
Yunjiang Zhang ◽  
Olivier Favez ◽  
Jean-Eudes Petit ◽  
Francesco Canonaco ◽  
Francois Truong ◽  
...  

Abstract. Organic aerosol (OA) particles are recognized as key factors influencing air quality and climate change. However, highly-time resolved year-round characterizations of their composition and sources in ambient air are still very limited due to challenging continuous observations. Here, we present an analysis of long-term variability of submicron OA using the combination of Aerosol Chemical Speciation Monitor (ACSM) and multi-wavelength aethalometer from November 2011 to March 2018 at a background site of the Paris region (France). Source apportionment of OA was achieved via partially constrained positive matrix factorization (PMF) using the multilinear engine (ME-2). Two primary OA (POA) and two oxygenated OA (OOA) factors were identified and quantified over the entire studied period. POA factors were designated as hydrocarbon-like OA (HOA) and biomass burning OA (BBOA). The latter factor presented a significant seasonality with higher concentrations in winter with significant monthly contributions to OA (18–33 %) due to enhanced residential wood burning emissions. HOA mainly originated from traffic emissions but was also influenced by biomass burning in cold periods. OOA factors were distinguished between their less- and more-oxidized fractions (LO-OOA and MO-OOA, respectively). These factors presented distinct seasonal patterns, associated with different atmospheric formation pathways. A pronounced increase of LO-OOA concentrations and contributions (50–66 %) was observed in summer, which may be mainly explained by secondary OA (SOA) formation processes involving biogenic gaseous precursors. Conversely high concentrations and OA contributions (32–62 %) of MO-OOA during winter and spring seasons were partly associated with anthropogenic emissions and/or long-range transport from northeastern Europe. The contribution of the different OA factors as a function of OA mass loading highlighted the dominant roles of POA during pollution episodes in fall and winter, and of SOA for highest springtime and summertime OA concentrations. Finally, long-term trend analyses indicated a decreasing feature (of about 200 ng m−3 yr−1) for MO-OOA, very limited or insignificant decreasing trends for primary anthropogenic carbonaceous aerosols (BBOA and HOA, along with the fossil fuel and biomass burning black carbon components), and no trend for LO-OOA over the 6+-year investigated period.


1982 ◽  
Vol 20 (17) ◽  
pp. 65-67 ◽  

The provision of high concentrations of oxygen is often part of the treatment of cardiac or respiratory disease. The use of domiciliary oxygen is generally limited to those patients with advanced chronic respiratory disease. It can be given in a number of ways - as continuous long-term therapy, as portable oxygen therapy, or intermittently for short periods. This article discusses the benefits and costs.


1998 ◽  
Vol 274 (2) ◽  
pp. C531-C542 ◽  
Author(s):  
Paul Smolen ◽  
Douglas A. Baxter ◽  
John H. Byrne

To examine the capability of genetic regulatory systems for complex dynamic activity, we developed simple kinetic models that incorporate known features of these systems. These include autoregulation and stimulus-dependent phosphorylation of transcription factors (TFs), dimerization of TFs, crosstalk, and feedback. The simplest model manifested multiple stable steady states, and brief perturbations could switch the model between these states. Such transitions might explain, for example, how a brief pulse of hormone or neurotransmitter could elicit a long-lasting cellular response. In slightly more complex models, oscillatory regimes were identified. The addition of competition between activating and repressing TFs provided a plausible explanation for optimal stimulus frequencies that give maximal transcription. Such optimal frequencies are suggested by recent experiments comparing training paradigms for long-term memory formation and examining changes in mRNA levels in repetitively stimulated cultured cells. In general, the computational approach illustrated here, combined with appropriate experiments, provides a conceptual framework for investigating the function of genetic regulatory systems.


2007 ◽  
Vol 16 (3) ◽  
pp. 349 ◽  
Author(s):  
Belén Luna ◽  
José M. Moreno ◽  
Alberto Cruz ◽  
Federico Fernández-González

This work documents the effect of a common, long-term fire retardant chemical, Fire-Trol 934, on seed viability and germination of 36 plant species growing in a burned Mediterranean area, covering different life-form types, regenerative strategies and distribution ranges. Seeds were subjected to four treatments: control, and application of Fire-Trol 934 at concentrations of 0.02, 0.2 and 2%. Fire-Trol 934 significantly decreased both seed viability and germination in the group of species studied, which suggests that Fire-Trol 934 may be toxic for seeds, at least when applied at high concentrations. Whereas seed viability generally showed a progressive decrease with increased Fire-Trol 934 concentration, germination percentages generally increased when intermediate Fire-Trol 934 concentrations were used, but tended to be drastically reduced when seeds were exposed to the highest (2%) concentration. The reduction observed in germination at the highest Fire-Trol 934 concentration was greater than that observed in viability, which suggests that the effect of Fire-Trol 934 on seeds may not be lasting. Little differences in the response to Fire-Trol 934 emerged among plant groups, all of which followed the general tendency described above.


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