THE ROLE OF ANTIFREEZE PROTEIN TYPE I IN ICE NUCLEATION INHIBITION

2006 ◽  
Vol 01 (03) ◽  
pp. 271-278 ◽  
Author(s):  
NING DU ◽  
X. Y. LIU ◽  
H. LI ◽  
CHOY LEONG HEW
Keyword(s):  
Antifreeze Proteins ◽  
Antifreeze Protein ◽  
Ice Nucleation ◽  
Type I ◽  
Nucleation Process ◽  
Nucleation Barrier ◽  
Ice Nuclei ◽  
Nucleation Model ◽  
Ice Crystallization

The effect of Antifreeze Protein Type I (AFP I, one type of fish antifreeze protein) on ice crystallization was examined quantitatively based on a "micro-sized ice nucleation" technique. It is found that Antifreeze Proteins can inhibit the ice nucleation process by adsorbing onto both the surface of ice nuclei and that of foreign dusts. This leads to an increase of the ice nucleation barrier and the desolvation kink kinetics barrier. Based on the latest nucleation model, the increases in the ice nucleation barrier and the kink kinetics barrier were measured. This enables us to quantitatively examine the antifreeze mechanism of AFP I.

scholarly journals Organic matter matters for ice nuclei of agricultural soil origin

2014 ◽  
Vol 14 (16) ◽  
pp. 8521-8531 ◽  
Author(s):  
Y. Tobo ◽  
P. J. DeMott ◽  
T. C. J. Hill ◽  
A. J. Prenni ◽  
N. G. Swoboda-Colberg ◽  
...  
Keyword(s):  
Organic Matter ◽  
Agricultural Soil ◽  
Source Region ◽  
Ice Nucleation ◽  
Desert Soil ◽  
Composition Analysis ◽  
Ice Nuclei ◽  
Show Evidence ◽  
Dry Heating

Abstract. Heterogeneous ice nucleation is a crucial process for forming ice-containing clouds and subsequent ice-induced precipitation. The importance for ice nucleation by airborne desert soil dusts composed predominantly of minerals is widely acknowledged. However, the potential influence of agricultural soil dusts on ice nucleation has been poorly recognized, despite recent estimates that they may account for up to 20–25% of the global atmospheric dust load. We have conducted freezing experiments with various dusts, including agricultural soil dusts derived from the largest dust-source region in North America. Here we show evidence for the significant role of soil organic matter (SOM) in particles acting as ice nuclei (IN) under mixed-phase cloud conditions. We find that the ice-nucleating ability of the agricultural soil dusts is similar to that of desert soil dusts, but is clearly reduced after either H2O2 digestion or dry heating to 300 °C. In addition, based on chemical composition analysis, we demonstrate that organic-rich particles are more important than mineral particles for the ice-nucleating ability of the agricultural soil dusts at temperatures warmer than about −36 °C. Finally, we suggest that such organic-rich particles of agricultural origin (namely, SOM particles) may contribute significantly to the ubiquity of organic-rich IN in the global atmosphere.

scholarly journals Type I Antifreeze Proteins Enhance Ice Nucleation above Certain Concentrations

2010 ◽  
Vol 285 (45) ◽  
pp. 34741-34745 ◽  
Author(s):  
Peter W. Wilson ◽  
Katie E. Osterday ◽  
Aaron F. Heneghan ◽  
Anthony D. J. Haymet
Keyword(s):  
Antifreeze Proteins ◽  
Ice Nucleation ◽  
Type I

scholarly journals Organic matter matters for ice nuclei of agricultural soil origin

2014 ◽  
Vol 14 (7) ◽  
pp. 9705-9728 ◽  
Author(s):  
Y. Tobo ◽  
P. J. DeMott ◽  
T. C. J. Hill ◽  
A. J. Prenni ◽  
N. G. Swoboda-Colberg ◽  
...  
Keyword(s):  
Organic Matter ◽  
Agricultural Soil ◽  
Source Region ◽  
Ice Nucleation ◽  
Desert Soil ◽  
Composition Analysis ◽  
Ice Nuclei ◽  
Show Evidence ◽  
Dry Heating

Abstract. Heterogeneous ice nucleation is a~crucial process for forming ice-containing clouds and subsequent ice-induced precipitation. The importance for ice nucleation of airborne desert soil dusts composed predominantly of minerals is relatively well understood. On the other hand, the potential influence of agricultural soil dusts on ice nucleation has been poorly recognized, despite recent estimates that they may account for up to ∼25% of the global atmospheric dust load. We have conducted freezing experiments with various dusts, including agricultural soil dusts derived from the largest dust source region in North America. Here we show evidence for the significant role of soil organic matter (SOM) in particles acting as ice nuclei (IN) under mixed-phase cloud conditions. We find that the ice nucleating ability of the agricultural soil dusts is similar to that of desert soil dusts, but is reduced to almost the same level as that of clay minerals (e.g., kaolinite) after either H2O2 digestion or dry heating to 300 °C. In addition, based on chemical composition analysis, we show that organic-rich particles are more important than mineral particles for the ice nucleating ability of the agricultural soil dusts at temperatures warmer than about −36 °C. Finally, we suggest that such organic-rich particles of agricultural origin (namely, SOM particles) may contribute significantly to the ubiquity of organic-rich IN in the global atmosphere.

scholarly journals Microbiology and atmospheric processes: the role of biological particles in cloud physics

2007 ◽  
Vol 4 (6) ◽  
pp. 1059-1071 ◽  
Author(s):  
O. Möhler ◽  
P. J. DeMott ◽  
G. Vali ◽  
Z. Levin
Keyword(s):  
Cloud Condensation Nuclei ◽  
Diffusion Chamber ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Potential Impact ◽  
The Impact

Abstract. As part of a series of papers on the sources, distribution and potential impact of biological particles in the atmosphere, this paper introduces and summarizes the potential role of biological particles in atmospheric clouds. Biological particles like bacteria or pollen may be active as both cloud condensation nuclei (CCN) and heterogeneous ice nuclei (IN) and thereby can contribute to the initial cloud formation stages and the development of precipitation through giant CCN and IN processes. The paper gives an introduction to aerosol-cloud processes involving CCN and IN in general and provides a short summary of previous laboratory, field and modelling work which investigated the CCN and IN activity of bacterial cells and pollen. Recent measurements of atmospheric ice nuclei with a continuous flow diffusion chamber (CFDC) and of the heterogeneous ice nucleation efficiency of bacterial cells are also briefly discussed. As a main result of this overview paper we conclude that a proper assessment of the impact of biological particles on tropospheric clouds needs new laboratory, field and modelling work on the abundance of biological particles in the atmosphere and their CCN and heterogeneous IN properties.

scholarly journals Microbiology and atmospheric processes: the role of biological particles in cloud physics

2007 ◽  
Vol 4 (4) ◽  
pp. 2559-2591 ◽  
Author(s):  
O. Möhler ◽  
P. J. DeMott ◽  
G. Vali ◽  
Z. Levin
Keyword(s):  
Cloud Condensation Nuclei ◽  
Diffusion Chamber ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Bacterial Cells ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Potential Impact ◽  
The Impact

Abstract. As part of a series of papers on the sources, distribution and potential impact of biological particles in the atmosphere, this paper introduces and summarizes the potential role of biological particles in atmospheric clouds. Biological particles like bacteria or pollen may be active as both cloud condensation nuclei (CCN) and heterogeneous ice nuclei (IN) and thereby can contribute to the initial cloud formation stages and the development of precipitation through giant CCN and IN processes. The paper gives an introduction to aerosol-cloud processes like CCN and IN in general and provides a short summary of previous laboratory, field and modelling work investigating the CCN and IN activity of bacterial cells and pollen. Recent measurements of atmospheric ice nuclei with a continuous flow diffusion chamber (CFDC) and of the heterogeneous ice nucleation efficiency of bacterial cells are also briefly discussed. As a main result of this overview paper we conclude that a proper assessment of the impact of biological particles on tropospheric clouds needs new laboratory, field and modelling work investigating the abundance of biological particles in the atmosphere and their CCN and heterogeneous IN properties.

Isoform-Selective PI3K Inhibitors for Various Diseases

2020 ◽  
Vol 20 (12) ◽  
pp. 1074-1092 ◽  
Author(s):  
Rammohan R.Y. Bheemanaboina
Keyword(s):  
Intracellular Signaling ◽  
Kinase Inhibitors ◽  
Therapeutic Potential ◽  
Type I ◽  
Selective Inhibitors ◽  
Pi3k Inhibitors ◽  
Wide Range ◽  
Lipid Kinases ◽  
Isoform Selectivity

Phosphoinositide 3-kinases (PI3Ks) are a family of ubiquitously distributed lipid kinases that control a wide variety of intracellular signaling pathways. Over the years, PI3K has emerged as an attractive target for the development of novel pharmaceuticals to treat cancer and various other diseases. In the last five years, four of the PI3K inhibitors viz. Idelalisib, Copanlisib, Duvelisib, and Alpelisib were approved by the FDA for the treatment of different types of cancer and several other PI3K inhibitors are currently under active clinical development. So far clinical candidates are non-selective kinase inhibitors with various off-target liabilities due to cross-reactivities. Hence, there is a need for the discovery of isoform-selective inhibitors with improved efficacy and fewer side-effects. The development of isoform-selective inhibitors is essential to reveal the unique functions of each isoform and its corresponding therapeutic potential. Although the clinical effect and relative benefit of pan and isoformselective inhibition will ultimately be determined, with the development of drug resistance and the demand for next-generation inhibitors, it will continue to be of great significance to understand the potential mechanism of isoform-selectivity. Because of the important role of type I PI3K family members in various pathophysiological processes, isoform-selective PI3K inhibitors may ultimately have considerable efficacy in a wide range of human diseases. This review summarizes the progress of isoformselective PI3K inhibitors in preclinical and early clinical studies for anticancer and other various diseases.

The Role of Toll-Like Receptors and Type I Interferons in Host Responses to Bacteria

2009 ◽  
Vol 5 (2) ◽  
pp. 143-149
Author(s):  
Marja Ojaniemi ◽  
Mari Liljeroos ◽  
Reetta Vuolteenaho
Keyword(s):  
Type I Interferons ◽  
Host Responses ◽  
Type I ◽  
Toll Like Receptors

scholarly journals Matrix degradation and cell proliferation are coupled to promote invasion and escape from an engineered human breast microtumor

2021 ◽  
Vol 13 (1) ◽  
pp. 17-29
Author(s):  
Emann M Rabie ◽  
Sherry X Zhang ◽  
Andreas P Kourouklis ◽  
A Nihan Kilinc ◽  
Allison K Simi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Type I ◽  
Matrix Degradation ◽  
Human Breast ◽  
Rate Of Invasion

Abstract Metastasis, the leading cause of mortality in cancer patients, depends upon the ability of cancer cells to invade into the extracellular matrix that surrounds the primary tumor and to escape into the vasculature. To investigate the features of the microenvironment that regulate invasion and escape, we generated solid microtumors of MDA-MB-231 human breast carcinoma cells within gels of type I collagen. The microtumors were formed at defined distances adjacent to an empty cavity, which served as an artificial vessel into which the constituent tumor cells could escape. To define the relative contributions of matrix degradation and cell proliferation on invasion and escape, we used pharmacological approaches to block the activity of matrix metalloproteinases (MMPs) or to arrest the cell cycle. We found that blocking MMP activity prevents both invasion and escape of the breast cancer cells. Surprisingly, blocking proliferation increases the rate of invasion but has no effect on that of escape. We found that arresting the cell cycle increases the expression of MMPs, consistent with the increased rate of invasion. To gain additional insight into the role of cell proliferation in the invasion process, we generated microtumors from cells that express the fluorescent ubiquitination-based cell cycle indicator. We found that the cells that initiate invasions are preferentially quiescent, whereas cell proliferation is associated with the extension of invasions. These data suggest that matrix degradation and cell proliferation are coupled during the invasion and escape of human breast cancer cells and highlight the critical role of matrix proteolysis in governing tumor phenotype.

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