Scientists build synthetic embryos without eggs or sperm

Rivron NC et al.  Blastocyst-like structures generated solely from stem cells. Nature, May 2018.

A new study reported the production of “synthetic embryos” without egg or sperm. The research team combined two types of stem cells from mice in cultures and then they implanted them into the womb lining of live female mice, where they initiated pregnancy. The implants successfully grew for a few days. While this experiment did not lead to the creation of a real embryo, this is the first time early body structures have been generated from stem cells. It is believed that whole organisms can potentially be formed from stem cells. Despite major medical advancements, very little is understood about how early embryos develop. Embryos are both ethically and technically challenging to study, as they’re very small, about the width of a human hair, and located inside the womb. By producing these embryo-like structures, however, these studies could reveal some crucial information about the early phases of life and help develop new drugs to deal with fertility problems. Many miscarriages occur in the very early stages of pregnancy, when the fertilized egg does not implant in the womb. Using stem cells, rather than sperm and eggs, to make model embryos could offer a plentiful supply for scientific research. There are currently no plans yet to repeat the results using human stem cells, as this issue is heavily debated and it would require a complicated approval process.

Even brief maternal deprivation can cause brain dysfunction in adulthood

Janetsian-Fritz SS et al. Maternal deprivation induces alterations in cognitive and cortical function in adulthood. Translational Psychiatry. March 2018

Maternal deprivation induces alterations in cognitive and cortical function in adulthood.

Researchers have found that when a baby is taken from its mother for even a brief period early in life, it can cause a traumatic cellular event that ultimately effects the function of the brain in adulthood. In the study, young rats were removed from their mothers for 24 hours when they were 9 days old, which is a critical period of rapid brain development. Later when the researchers analyzed the brain scans of these animals in adult stages, they exhibited significant biological, physiological, and behavioral brain abnormalities in adulthood. More specifically, these rats showed memory impairment and reduced communication between brain regions, when compared to control rats. Interestingly, these changes in the brain look very similar to disturbances in brain structure and function that are found in people at risk for neuropsychiatric disorders, such as schizophrenia. Rat and human brains have similar structures and connectivity, and researchers hope that understanding what happens in the brain of a young rat that’s removed from its mother might give us important insights into how this type of early trauma can affect the young human brain. The more we understand how the brain responds, the closer we come to being able to address and hopefully develop novel treatment strategies to reverse these neurological changes. Children exposed to early-life stress or deprivation are at higher risk for mental illness and addictions later in life, including schizophrenia. These studies are expected to provide clues to how a traumatic event early in life could increase a person’s risk of emotional disorders and what kind of policies or interventions might alleviate stress for children and should be developed to reduce the possibilities of such disorders developing.

The critical limit for global warming: 1.5 degrees Celsius

Warren R. et al. The projected effect on insects, vertebrates, and plants of limiting global warming to 1.5°C rather than 2°C. Science, May 2018

A new study claims that if we can manage to keep global warming below 1.5 ^oC, which is the ambitious goal of the 2016 Paris Agreement, we can save the vast majority of the world’s plant and animal species from climate change. Researchers in this study have analyzed

115,000 species, including 31,000 insects, 8,000 birds, 1,700 mammals, 1,800 reptiles, 1,000 amphibians, and 71,000 plants, to see how different projected climate futures may cause effect these species, measuring the risks to biodiversity by counting the number of species projected to lose more than half their geographic range due to climate change. Their analyses showed that achieving the ultimate goal of the Paris Agreement, or limiting warming to 1.5^oC above pre-industrial levels, is critical for the survival of biodiversity. They also found that insects will be particularly sensitive to climate change, as 18% of the 31,000 insects are projected to lose more than half their range at 2^oC increase. This can be reduced to 6% at a 1.5^oC increase. The current global warming trajectory, if countries meet their international pledges to reduce CO₂, is unfortunately around 3^oC. In this case, almost 50% of insects would lose half their range. Insects are extremely vital to ecosystems and for humans. They have a long list of duties: to pollinate crops and flowers, provide food for higher-level organisms, break down detritus, maintain a balance in ecosystems by eating the leaves of plants, and help recycle nutrients in the soil. Ultimately, it won’t be just the biodiversity that suffers if the temperature rises too much, but the human race as well. The world is heating up. It’s no longer a case of if this is happening, but rather how fast can we limit the damage.

Greenhouse Gases and the Greenhouse Effect

A greenhouse is a place that is usually covered with glass or plastic walls where early season vegetables and house-plants are cultivated. Rays from the Sun can easily penetrate a greenhouse, but once they hit the ground they are transformed into thermo-energy, with the wavelength of the beams shortening and their energy diminishing. As a result, these beams with a shorter wavelength cannot leave the greenhouse due to the glass or plastic walls. Therefore the warming of the greenhouse increases as more and more rays enter. We call this process the greenhouse effect.

Similarly, some gases in the strata of the atmosphere are called greenhouse gases since these gases cause the same greenhouse effect for the Earth. These gases include carbon dioxide, methane, nitrogen oxide, ozone, chlorofluorocarbon, and water vapor. These gases have been created with a property that does not prevent (or prevents to a very small extent) the light energy that comes from the Sun from reaching the Earth and that prevents the infrared heat energy waves that are formed after this energy reaches the Earth from radiating to the higher layers of the atmosphere. Both the Earth and the layers of the atmosphere close to the Earth are heated by these gases. If there were not any of these gases surrounding the Earth it is estimated that the Earth would be 33° C colder. Although there is a delicate balance and measure among the gases in the atmosphere that allows the maintenance of the Earth’s temperature at a sensible level, human beings are carrying out practices that can ruin this balance. We, as human beings, are responsible for the global warming that is perceived as a danger today.

Carbon Dioxide

Carbon dioxide is half the reason for the total greenhouse effect. This gas is formed as a result of the use of fossil fuels, the respiration of humans, animals, and plants, and the disintegration of organic substances. Industrial development has caused a rapid increase in carbon dioxide in the atmosphere. It is known that 85% of the carbon dioxide emitted into the atmosphere comes from fossil fuels, with 15-20% stemming from the respiration of living beings and the other ecological continuous cycles.

In the last 150 years, a total of 389 Gt of carbon dioxide has been emitted into the atmosphere. 265 Gt of this carbon dioxide comes from the consumption of fossil fuels and the production of cement. 124 Gt comes from changes in land use. 214 Gt of this total has been reabsorbed by land and sea ecosystems and the oceans. This means that there is a surplus of 175 Gt of carbon dioxide in the atmosphere.

The Importance of the Forests

Forests play an essential role in lowering the diffusions of greenhouse gases that are emitted into the atmosphere and in forming “carbon absorption” by occluding greenhouse gases in the atmosphere. Thus, except for sedimentary rocks, 67% of the carbon kept on the land is stored in the forest ecosystem. 75% of the carbon kept by vegetation is stored in the forests. In addition, as long as some long-lived wooden products (wooden houses, furniture, etc.) decay or are burnt they remain as carbon storages.

As we all know, during photosynthesis the carbon dioxide that is taken from the atmosphere is separated into carbon and oxygen molecules. Then the carbon is stored in the roots, trunks, branches, and leaves of plants, being used in order to form carbon hydrates. Therefore carbon dioxide, the most essential greenhouse gas, becomes balanced. We can compare this to a huge factory that works very quietly and causes no waste. It is such an efficient factory that it transforms harmful substances into useful ones. We cannot say that we human beings appreciate this factory or protect its resources. Although today forests cover 3.7 billion hectares, comprising 30% of all land, between the years 1990–2000 on average 9.4 million hectares of forest were annually removed. That means that during this period the forest regions of the world diminished by 2%. As a result of such negative occurrences, because the carbon balance of vegetation, soil and organic substances had been destroyed, the forests, one of the means of God’s mercy upon us, have become sources of carbon dioxide and a tragedy due to our exploitation.

Ligneous living masses increase each year, while falling leaves add to the carbon storage. As a result, forest ecosystems contain carbon. After the growth of trees, most of the carbon dioxide they occlude each year goes toward developing the biomass of the tree. This means that in the first 30-40 years a high rate of carbon storage occurs. As the forest ecosystem develops, the organic substance of the soil and the total respiration in the ecosystem (occlusion of carbon dioxide) increase. When the ecosystem has fully developed, it no longer has the characteristics of “carbon absorption” anymore. In this case, the amount of carbon taken from the atmosphere is equal to the carbon emitted back by the biomasses of the trees and is kept in the soil. The time it takes for a tree to fully develop depends on the type of tree and the climate zones. However most of the carbon storage occurs in the first 60-100 years. It has been determined by research that a well-developed 100 year-old beech tree absorbs 40,000,000 m_ of air with its leaves for photosynthesis and binds 1,200 m_ of carbon dioxide in the air as 6 tons of carbon.

As well as being a community of trees, forests are environmental systems and living communities, with soil that was created over a thousand years, with millions of plants, animals, and microorganisms, and their reciprocal relationships. It is very difficult for this system to be restored once destroyed by human beings. Forests provide an essential service in a consistent and balanced carbon flow between the biosphere and the atmosphere with respiration that is dependent on photosynthesis and the activities of life in the soil and the plants. Forests are the lungs of the Earth.

In the light of these facts, the duty of human beings is to protect the vegetation and to reforest the treeless lands, to decrease human pressure on existing forests and to improve forests that have been damaged. Oxygen, nitrogen, water vapor, and carbon dioxide were created as continuous cycles for the continuation of the life. When these treasures have been damaged as a result of the greed of human beings, the costs are too high for us to reverse the trend. Billions of people are victimized; yet they are nor directly responsible for such acts. These delicate balances can be revived if we lead a simple and modest life, where we consume less and we produce less. Those who ought to understand this first must promise to be more respectful to God and to change themselves. Even if we fulfill our responsibilities, we can do nothing today but hope that those whose destructive powers are great may desire such a spiritual revolution.

References

• Cepel, N., Ekolojik Sorunlar ve Cozumleri, Tubitak Populer Bilim Kitaplar›, Ankara: 2003.
• Roulet, N.T., Freedman, B., What Trees Can Do to Reduce Atmosferic CO2, Tree Canada Foundation, Ontario: 2003.
• Report by the Commission of Climate Change Experts, DPT (Turkey’s Official Planning Organization), Ankara: 2001.
• Food and Agriculture Organization of the United Nations, 2001, Global Forest Resources Assesment 2000, ISSN 0258-6150, FAO Forestry Paper:140.