November 27, 2019
Development of a bacterium (Escherichia coli) that produce all its biomass carbon from CO2.
Most of Earth’s atmosphere is composed of nitrogen and oxygen. However, these gases cannot absorb the infrared radiation emitted by Earth. Whereas, Carbon dioxide (CO2) and water vapor, which are of trace amounts in the atmosphere can absorb the infrared radiation of Earth. After these gases absorb the energy, they emit half of it back to Earth and half of it into space, trapping some of the heat within the atmosphere. This trapping of heat is what we call the greenhouse effect. Because of the greenhouse effect created by these trace gases, the average temperature of the Earth is around 15˚C, or 59˚F, which allows for life to exist. While water vapor is the dominant greenhouse gas in our atmosphere, it allows some of the infrared energy to escape without being absorbed. In addition, water vapor is concentrated lower in the atmosphere, whereas CO2 mixes well all the way to about 50 kilometers up. The higher the greenhouse gas, the more effective it is at trapping heat from the Earth’s surface.
The burning of fossil fuels affects the concentration of CO2 in the atmosphere. If the CO2 doubles from the present level, it could raise the average global temperature of the Earth between two and five degrees Celsius. Increasing the amount of energy that bounces back to the Earth causes the greenhouse effect that leads to global warming with its many destructive impacts.
Both water vapor and CO2 are responsible for global warming; increasing the levels of CO2 in the atmosphere leads to a warming ocean that inevitably triggers an increase in water vapor. Though we cannot control the levels of water vapor in the atmosphere, we can control CO2. Continuing to burn fossil fuels will lead to an increase in the amount of CO2 in the atmosphere thereby disturbing the entire heat balance of the planet.
Scientists are working on different strategies to reduce the CO2 levels in the atmosphere. Carbon dioxide can be captured out of air, industrial source or from power plants using a variety of technologies, including absorption, adsorption, chemical looping, or membrane gas separation technologies. Storage of the CO2 is envisaged either in deep geological formations, or in the form of mineral carbonates.
Gleizer, Milo and their team has reported in the journal Cell (179: 1255-1263) a novel method of reducing CO2 in the atmosphere. They have engineered the bacterium Escherichia coli to produce all its biomass carbon from CO2. Thus, the bacterium used CO2 for growth rather than sugar or other organic molecules. Their engineered E. coli strain uses the Calvin-Benson-Bassham cycle (CBB, also referred to as Calvin cycle for short) for carbon fixation and harvests energy and reducing power from the one-carbon molecule formate (HCOO−), which can be produced electrochemically. The stepwise bioengineering process required co-expression of Calvin cycle enzymes and an energy harvesting enzyme, rational rewiring of the endogenous metabolic network, and adaptive laboratory evolution to achieve the desired trophic mode transformation. In the future, CO2-eating E. coli could be used to make organic carbon molecules that could be used as biofuels or to produce food.
November 25, 2019
Generation of Spider‐Silk‐Like Super tough Fibers using a Pseudoprotein Polymer
Spider silk is five times stronger than steel. Each strand of spider silk is thousand times thinner than a human hair and is made up of thousands of nanostrands. The remarkable mechanical properties of spider silk compared to steel and Kevlar has kindled interest in the material. The power of spider silk is demonstrated by one particular silk called aciniform silk, which is used for wrapping prey and lining egg cases. The aciniform silk is one of the toughest biological materials. This silk is extremely thin (around 1 micometer in diameter) but can control animals such as bats and birds. Spiders are cannibals making farming impossible; hence, other sources are used to generate spider silk. Genetic engineering spider silk is challenging to scale up due to low efﬁciency, high cost, and uncontrollable quality of the process.
A new chemical synthesis method to generate spider silk-like materials efficiently is first reported by Gu et al., in the journal Advanced Materials (Vol. 31). Super toughness (≈387 MJ m−3), more than twice the reported value of common spider dragline silk and comparable to the value of the toughest spider silk, the aciniform silk of Argiope trifasciata, is achieved by introducing beta sheet crystals and alpha helical peptides simultaneously in a pseudoprotein polymer. The process opens up a very promising avenue for obtaining excellent spider fibers.
November 21, 2019
The dung beetle horn is influenced by wing genes
The dung beetles are the cleaners of the environment. They enrich the soil by burying the dung thereby playing a vital role in the nutrient recycling. The dung beetles are known to rely on heavenly stars for navigation.
The dung beetle use their horn –on the head and thorax- for fighting its opponents – for the choicest dung. Understanding how novel complex traits originate is a foundational challenge in evolutionary biology. Hu et al. reports in Science (366: 1004-1007) that the horn of the dung beetles generated from wing genes.
The authors designed fragments of RNA that would destroy specific genes critical for wing development. When the RNA was injected into dung beetle larvae, it was not just the wings that were reduced in size or completely absent; the horns were also small or failed to grow on the bodies of all different beetle species. The study demonstrated that the wing genes are turned on during the early stages of horn growth.
November 20, 2019
Tropical storm Fung-Wong (Sarah) in the Philippine Sea
November 19, 2019
Ketogenic diet activates protective T cell against influenza virus infection
Influenza A virus (IAV) infection–associated morbidity and mortality are a key global health care concern, necessitating the identification of new therapies capable of reducing the severity of IAV infections. Previous studies showed that high fiber diet could protect against IAV. Goldberg et al. in a recent issue of Science Immunology (4: Issue 41, eaav2026) reports that in an animal model a high-fat, low-carbohydrate ketogenic diet confers protection against IAV. Feeding a ketogenic diet in animals resulted in an expansion of gamma delta T cells in the lung that improved barrier functions, thereby enhancing antiviral resistance. Harnessing the beneficial effects of a ketogenic diet through gamma delta T cells may therefore offer a potential previously unrecognized avenue for influenza disease prevention and treatment.
November 18, 2019
Extraterrestrial sugars in primitive meteorites
It is still not understood how life started on our planet. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are the genetic molecules of life and sugars are the indispensable constituents of these molecules. Ribose sugar is the building block of RNA, which could have both stored information and catalyzed reactions in primitive life on Earth. A meteorite is a fragment of rock or iron from outer space that survived passage through the atmosphere as a meteor to impact the surface of the Earth. Among the constituent molecular classes of proteins and nucleic acids (i.e., amino acids, nucleobases, phosphate, and ribose/deoxyribose), the presence of ribose and deoxyribose in space remains unclear. Meteorites are known to contain a number of organic compounds including key building blocks of life, i.e., amino acids, nucleobases, and phosphate. Previously an amino acid has also been identified in a cometary sample. Furukawa et al. in the journal PNAS (Nov. 18) (https://doi.org/10.1073/pnas.1907169116) provide evidence of extraterrestrial ribose and other bioessential sugars in primitive meteorites. Meteorites are potential carriers of prebiotic organic molecules to the early Earth and the detection of extraterrestrial sugars in meteorites implies the possibility that extraterrestrial sugars may have contributed to forming functional biopolymers like RNA.
November 16, 2019:
Butyrate-producing microbes are responsible for improving the physiology of the hosts.
The host microbiome (all the microorganisms in our body) is involved in health or diseases. Our health or lack of health is the sum of the nature of microorganisms living in us. Our gut microbiota evolves as we age, yet its effects on host physiology are not clearly understood. Kundu et al. reported in the journal Science Translational Medicine (11: eaau4760) how the microbiome impacts the host physiology. The authors elucidated the changes in physiology by transplanting the gut microbiota of either young or old donor mice into young germ-free recipient mice. The young germ-free mice receiving gut microbiota transplants from old mouse donors exhibited increased hippocampal neurogenesis, intestinal growth, and activation of the proteins that impacts the liver metabolism. The authors identified that the butyrate-producing microbes are responsible for improving the physiology of the hosts. Butyrate is produced by microorganisms that feed on fiber rich foods. The study shows that eating a diet rich in food may impact your health.
November 15, 2019:
Tropical storm Fengshen in the Pacific Ocean.
November 9, 2019:
Cyclone Bulbul moving into India from Bay of Bengal and Typhoon Nakri in South China Sea, off the coast of Vietnam.
Genetic history shows that many imperial Romans had its roots in the Middle East
Ancient Rome was the capital of the Roman empire encompassing the regions around the Mediterranean Sea. However, little is known about the ancestry of ancient Rome. Antonio et al. published in the journal Science (Vol. 366, pp. 708-714) a paper on genetic changes that occurred in Rome and central Italy from the Mesolithic into modern times. The authors reports two major prehistoric ancestry transitions: one with the introduction of farming and another prior to the Iron Age. During the Imperial period, Rome’s population received a large population of immigrants from the Near East. Of 48 individuals sampled from this period, only two showed strong genetic ties to Europe. Another two had strong North African ancestry. The rest had ancestry connecting them to Greece, Syria, Lebanon, and other places in the Eastern Mediterranean and Middle East. After the imperial empire split in two and the eastern capital moved to Constantinople (modern Istanbul, Turkey) in the fourth century AD, Rome’s genetic diversity decreased. The trade shifted to the new capital, and epidemics and invasions reduced Rome’s population to about 100,000 people. Invading barbarians brought in more European ancestry. Rome gradually lost its strong genetic link to the Eastern Mediterranean and Middle East. By medieval times, city residents genetically resembled European populations.
Development of a floatable super hydrophobic structure for aquatic applications
A highly floating multi-faced super hydrophobic structure inspired by the diving bell spiders and fire ant assemblies is developed and reported by Zhan et al., in the journal ACS Applied Materials and Interfaces. As yet, there are no structures that are super hydrophobic that could float in water, even when damaged. The authors design a structure that refuses to sink even after severe damage and piercing. The structure uses a novel technique the laboratory developed using femtosecond bursts of lasers to “etch” the surfaces of metals with intricate micro- and nanoscale patterns that trap air and make the surfaces super-hydrophobic (water hating). The laboratory created a structure in which the treated surfaces on two parallel aluminum plates face inward, not outward, so they are enclosed and free from external wear and abrasion. The surfaces are separated by just the right distance to trap and hold enough air to keep the structure floating- in essence creating a waterproof compartment. The super hydrophobic surfaces can trap a large air volume thereby using the material for buoyant devices. Even after being forced to submerge for two months, the structures immediately bounced back to the surface after the load was released. The structures also retained this ability even after being punctured multiple times, because air remains trapped in remaining parts of the compartment or adjoining structures. Though the team used aluminum for the study, the etching method could be used for any metals. The potential use of the super hydrophobic floating metallic assembly ranges from floating devices and electronic equipment protection, to ships and vessels.