International Journal of Toxicology and Toxicity Assessment

Regulation of transgelin and GST-pi proteins in the tissues of hamsters exposed to sodium arsenite.

Uttam Kumar Chowdhury

Hamsters were exposed to sodium arsenite (173 mg As/L) in drinking water for 6 days. Equal amounts of proteins from urinary bladder or liver extracts of control and arsenic-treated hamsters were labeled with Cy3 and Cy5 dyes, respectively. After differential in gel electrophoresis and analysis by the DeCyder software,several protein spots were found to be down-regulated and several were up regulated. Our experiments indicated that in the bladder tissues of hamsters exposed to arsenite, transgelin was down-regulated and GST-pi was up-regulated. The loss of transgelin expression has been reported to be an important early event in tumor progression and a diagnostic marker for cancer development [29-32]. Down-regulation transgelin expression may be associated with the carcinogenicity of inorganic arsenic in the urinary of bladder. In the liver of arsenite-treated hamsters, ornithine aminotransferase was up-regulated, and senescence marker protein 30 and fatty acid binding protein were down-regulated. The volume ratio changes of these proteins in the bladder and liver of hamsters exposed to arsenite were significantly different than that of control hamsters.

Does and duration of exposure time dependent regulation of proteins in the urinary bladder of hamsters exposed to sodium arsenite 

Uttam Kumar Chowdhury

Inorganic arsenic is a known human carcinoge1. Millions of people are exposed to it from naturally contaminated drinking water1-4. Chronic exposure to inorganic arsenic can cause cancer of the skin, lungs, urinary bladder, kidneys, and liver1, 3, 5-8. The toxic effects of inorganic arsenics are does depended and high exposure produce cytotoxicity9 and carcinogenicity9-11.Many mechanisms of arsenic toxicity and carcinogenicity have been suggested 12, 13 including chromosome abnormalities 14, oxidative stress 15, 16, altered growth factors 17, cell proliferation 18, altered DNA repair 19, altered DNA methylation patterns 20, inhibition of several key enzymes 21, gene amplification 22 etc. Some of these mechanisms result in alterations in protein expression. The mechanism of arsenic species having a +3 oxidation state biotransformants, methylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII) has been claimed to be their reaction with thiols of proteins and conformational alteration of protein structure13. It is ultimately the change in protein expression that alters the cellular response. Evaluation of the proteome may lead to a more specific measure and mechanism of arsenic toxicity. Mice exposed to 0.01 % sodium arsenite in drinking water develop hyperplasia of the bladder urothelium within 4 weeks of exposure, as well as increased in DNA binding of the activating protein (AP)-1 transcription factor 17. Although there has been no generally accepted animal model for inorganic arsenic carcinogenesis, the hamster is considered to be an excellent model for how the human process inorganic arsenic because of its urinary arsenic profile and the relatively low affinity of its red blood cells for arsenic metabolites 12, 23-25.

Methods for analyzing multiple proteins have advanced greatly in the last several years. In particularly, mass spectrometry (MS) and tandem MS (MS/MS) are used to analyze peptides following protein isolation using DIGE and proteolytic digestion 26. The use of Differential in Gel Electrophoresis (DIGE), an exquisitely sensitive and accurate proteomic technology to study arsenic toxicology now has the potential of obtaining more specific knowledge as to the exact role of specific proteins in arsenic intoxication and detoxification.

In the present study, DIGE coupled with Mass Spectrometry (MS) has been used to study some of the proteomic changes in the urinary bladder of hamsters exposed to sodium arsenite in their drinking water. Our results indicated that transgelin a protein important in tumor progression

Will Catalysts Save Our Environment?

Suryakiran Navath

If you own a car, then at some point in your life, you’ll end up having to go to the mechanic to address any emergent car troubles. You may experience engine troubles, slower acceleration, or smoke coming out of your car’s exhaust, only to find out that you have a “bad cat.” What do these cute little furballs have to do with cars?

Well, it’s not an actual cat, just in case you were worrying about that. The “cat” in question is a catalytic converter – a component in your car’s exhaust system that contains catalysts to reduce pollution in the environment.

Catalysts are materials that speed up chemical reactions by facilitating them such that bond breaking and formation processes require less energy to undergo. During their interaction in the reaction, they do not get spent but rather get recycled as long as the reaction continues.

Since the ’70s, catalytic converters have been helping reduce NO_X, SO_X, CO_X, and other exhaust waste gases in vehicles and industrial processes throughout the world. This use of catalysts on a major scale ushered in an era of green chemistry where scientists and researchers look for ways to tackle the environmental problems that plague our world. So, will catalysts save our environment?

Electrocatalysis

These days, scientists are actively working on finding solutions to reducing the carbon dioxide in our environment via carbon capture and utilization technology. This technology works to reduce carbon dioxide into a substance that does not contribute to global warming. The main chemical reaction involves reducing carbon dioxide to carbon monoxide, which can then be

Used to make new compounds that serve as raw materials and fuel for our industries..

Homo SapiensSapiens Progressive Defaunation During The Great Acceleration: The Cli-Fi Apocalypse Hypothesis

ElhoucineEssefi

The Great Acceleration may be considered as the Late Anthropocene in which Man actions reached their climax to lead to dramatic climatic changes paving the way for a possible apocalyptic scenario threatening the existence of the humanity.So, the apocalyptic scenariois not a pure imagination of the literature works. Instead, many scientific arguments especially related to climate change are in favour of the apocalypse1. As a matter of fact, the modelling of the future climate leads to horrible situations including intolerable temperatures (In 06/07/2021, Kuwait recorded the highest temperature of 53.2 °C), dryness, tornadoes, and noticeable sear level rise evading coastal regions. These conditions taking place during the Great Acceleration would have direct repercussions on the human species.

Considering that the apocalyptic extinction had really caused the disappearance of many stronger species including dinosaurs, Homo Sapiens Sapiens extended his imagination though the Climate-Fiction (cli-fi) to propose a dramatic end due to severe climate conditions intolerable by the humankind. The mass extinction of animal species has occurred several times over the geological ages.Researchers have a poor understanding of the causes and processes of these major crises1. Nonetheless, whatever the cause of extinction, the apocalyptic scenario has always been present in the geological history. For example, dinosaurs extinction either by asteroids impact or climate changes could by no means denies the apocalyptic aspect2.At the same time as them, many animal and plant species became extinct, from marine or flying reptiles to marine plankton. This biological crisis of sixty-five million years ago is not the only one that the biosphere has suffered. It was preceded and followed by other crises which caused the extinction or the rarefaction of animal species. So, it is undeniable that many animal groups have disappeared. It is even on the changes of fauna that the geologists of the last century have based themselves to establish the scale of geological times, scale which is still used. But it is no less certain that the extinction processes, extremely complex, are far from being understood. We must first agree on the meaning of the word "extinction", namely on the apocalyptic aspect of the concept. It is quite understood that, without disappearances, the evolution of species could not have followed its course. Being aware that the apocalyptic extinction had massacred stronger species that had dominated the planet, Homo Sapiens Sapiens has been aware that the possibility of apocalyptic end at the perspective of the Anthropocene (i.e., Great Acceleration) could not be excluded. This conviction is motivated by the progressive defaunation in some regions 3 and the appearance of alien species in others related to change of mineralogy and geochemistry4 leading to a climate change during the Anthropocene.

These scientific claims fed the vast imagination about climate change to set the so-called cli-fi. The concept of the Anthropocene is the new geological era which begins when the Man actions have reached a sufficient power to modify the geological processes and climatic cycles of the planet5. The Anthropocene by no means excludes the possibility of an apocalyptic horizon, namely in the perspectives of the Great Acceleration. On the contrary, two scenarios do indeed seem to dispute the future of the Anthropocene, with a dramatic cross-charge. The stories of the end of the world are as old as it is, as the world is the origin of these stories. However, these stories of the apocalypse have evolved over time and, since the beginning of the 19th century, they have been nourished particularly by science and its advances. These fictions have sometimes tried to pass themselves off as science. This is the current vogue, called collapsology6. This end is more than likely cli-fi driven7and it may cause the extinction of the many species including the Homo Sapiens Sapiens. In this vein, Anthropocene defaunation has become an ultimate reality8. More than one in eight birds, more than one in five mammals, more than one in four coniferous species, one in three amphibians are threatened. The hypothesis of a hierarchy within the living is induced by the error of believing that evolution goes from the simplest to the most sophisticated, from the inevitably stupid inferior to the superior endowed with an intelligence giving prerogative to all powers. Evolution goes in all directions and pursues no goal except the extension of life on Earth. Evolution certainly does not lead from bacteria to humans, preferably male and white. Our species is only a carrier of the DNA that precedes us and that will survive us. Until we show a deep respect for the biosphere particularly, and our planet in general, we will not become much, we will remain a predator among other predators, the fiercest of predators, the almighty craftsman of the Anthropocene. To be in the depths of our humanity, somehow giving back to the biosphere what we have taken from it seems obvious. To stop the sixth extinction of species, we must condemn our anthropocentrism and the anthropization of the territories that goes with it. The other forms of life also need to keep their ecological niches.

According to the first, humanity seems at first to withdraw from the limits of the planet and ultimately succumb to them, with a loss of dramatic meaning. According to the second, from collapse to collapse, it is perhaps another humanity, having overcome its demons, that could come. Climate fiction is a literary sub-genre dealing with the theme of climate change, including global warming. The term appears to have been first used in 2008 by blogger and writer Dan Bloom. In October 2013, Angela Evancie, in a review of the novel Odds against Tomorrow, by Nathaniel Rich, wonders if climate change has created a new literary genre. Scientific basis of the apocalyptic scenario in the perspective of the Anthropocene.

Stability of monomethylarsonous acid (MMAIII) and dimethylarsinous acid (DMAIII) in human urine and mouse tissues

Uttam K Chowdhury

Urine samples were collected from 75 subjects in the Lagunera area of Mexico. There were four groups, based on total arsenic concentrations in their drinking water (9 100μg/L). After collection, the samples were immediately put in a portable icebox containing dry ice, and they were kept frozen while being transported to the University of Arizona, Tucson where they were stored at -70°C before analysis. Arsenic metabolites, including MMA(III) and DMA(III), were measured in urine samples by using HPLC-ICP MS. The average percentage of MMA(III) in urine samples of arsenic exposed people in the Lagunera area of Mexico were 0.44%, 0.26%, N.D. (Not Detectable), and 0.20% of total arsenic for the groups 4, 1, 3, and 2 where arsenic concentrations in their drinking water were 9, 17.5, 52, and 100 (µg/L), respectively. This small percentage of MMA(III) were detected only in 14 urine samples (~18%) out of total 75 samples. DMA(III) was not measured in any of these urine samples (n=75) but measured DMA(V) in all samples. The highest percentage of arsenic metabolites was DMA(V) (61% to 74%) of the total arsenic in urine. It indicates that most of the MMA(III) methylated to DMA(V) in tissues, but less percentage or most of the DMA(V) may be reduced to DMA(III) and due to its instability, it could be immediately oxidized to DMA(V) in tissues again or in urine after collection. These findings suggest that the +5-oxidation state of arsenic metabolite, DMA(V), could be the most dominant methylated arsenic metabolite in humans’ urine of arsenic exposed population.

Arsenic Health Impacts to the People in Bangladesh

Uttam K Chowdhury

In our study in Bangladesh (1995-2000), we had analyzed 33,092 hand tube well water samples from all 64 districts and found arsenic in 60 districts above the WHO recommended value in drinking water (10 μg/L) and in 50 districts above maximum permissible limit, 50 μg/L. This does not mean that total population in these 50 districts are drinking arsenic contaminated water and suffering from arsenicosis, but undoubtedly, they are at risk. Patients with arsenical skin lesions are expected in 50 out of 64 administrative districts in Bangladesh, where we have found arsenic in groundwater above 50 μg/L.

Literatures survey show that arsenic concentration in the body tissues and fluids increase as arsenic concentration in the drinking water1 increases. Arsenic concentration is higher in hair and nails than in other parts of the body because of the high content of keratin, the SH groups of which might bind trivalent inorganic arsenic2-4.

Ingestion of inorganic arsenic is now an established cause of skin cancer5,6,7. Recent studies provide evidence that ingestion of arsenic can also cause cancers of the lung and the urinary bladder. According to WHO5, 1.0 mg of inorganic arsenic per day may give rise to skin effects within a few years. It has been estimated that based upon the current U.S. Environmental Protection Agency (EPA) standard of 50 μg/L, the lifetime risk of dying from cancer of the liver, lung, kidney, or bladder, from drinking 1 liter per day of water could be as higher 13 per 1000 persons6. In the latest document on arsenic in drinking water, U.S. National Research Council (NRC) concluded that exposure to 50 μg/L could easily result in a combined cancer risk7 of 1 in 100.

In this paper, I will report (a) arsenic impact/toxic effects to the people due to drinking arsenic contaminated underground water in Bangladesh, (b) arsenic effects to the people in rich family members versus under-poverty line family members, and (c) children are at risk in arsenic affected areas of Bangladesh.