Tag Archives: photosynthesis

Scientists Uncover Mesozoic Carbon Dioxide Levels and Photosynthesis Through Dinosaur Tooth Enamel Analysis

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During the Mesozoic era, from 252 to 66 million years ago, analyses of the oxygen isotope composition in dinosaur teeth revealed that the atmosphere contained significantly more carbon dioxide than it does today, with global plant photosynthesis levels roughly double those of the present.

Fossil teeth of Camarasaurus from the Morrison Formation in the US. Image credit: sauriermuseum aathal.

A study conducted by Göttingen University and researcher Dr. Dingsu Feng examined the dental enamel of dinosaurs that roamed North America, Africa, and Europe during the Late Jurassic and Late Cretaceous periods.

“Enamel is one of the most stable biological materials,” they explained.

“It captures different oxygen isotopes based on the air dinosaurs inhaled with each breath.”

“The isotope ratios of oxygen reflect fluctuations in atmospheric carbon dioxide and plant photosynthesis.”

“This connection allows us to infer insights about the climate and vegetation of the dinosaur era.”

“During the late Jurassic, about 150 million years ago, the air contained four times more carbon dioxide than before industrialization, prior to significant human emissions of greenhouse gases.”

“In the late Cretaceous, around 730 to 66 million years ago, carbon dioxide levels were three times higher than today.”

Teeth from two dinosaur species, the Tyrannosaurus Rex and Kaatedocus siberi, showed an exceptionally unique oxygen isotope composition.

This phenomenon is indicative of carbon dioxide spikes linked to major geological events like volcanic eruptions—such as the massive eruption of the Deccan Traps in India at the close of the Cretaceous period.

The heightened photosynthetic activity of plants at that time on both land and water is likely associated with elevated carbon dioxide levels and higher average annual temperatures.

This research marks a milestone in paleoclimatology. Historically, soil and marine proxy carbonates have served as the primary tools for reconstructing past climates.

Marine proxies, which are indicators of sediment fossils and chemical signatures, help scientists comprehend ancient marine environmental conditions, yet these methods often involve uncertainties.

“Our approach offers a fresh perspective on the planet’s history,” Dr. Fenn remarked.

“It paves the way to use fossilized tooth enamel for probing the composition of Earth’s atmosphere and plant productivity during that era.”

“Understanding these factors is crucial for grasping long-term climate dynamics.”

“Dinosaurs may well become new climate scientists, as their teeth have recorded climate data for over 150 million years. At last, we have received their message.”

Study published on August 4, 2025, in Proceedings of the National Academy of Sciences.

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Dingsu Feng et al. 2025. Mesozoic Atmospheric CO2 Concentrations reconstructed from the enamel of dinosaur teeth. PNAS 122 (33): E2504324122; doi: 10.1073/pnas.2504324122

Source: www.sci.news

A recently identified gene enhances photosynthesis and boosts plant growth

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Biologists have identified a new gene California poplar trees (Populus trichocarpa) — named booster —It can promote photosynthesis and increase the height of trees.

Transgenic hybrid poplar with increased expression levels BSTR Increased photosynthetic efficiency and biomass under greenhouse conditions. Image credit: Feissa others., doi: 10.1016/j.devcel.2024.11.002.

“Historically, much research has focused on steady-state photosynthesis, where all conditions remain constant,” the co-senior authors said. Dr. Stephen Burgessa researcher at the University of Illinois at Urbana-Champaign.

“However, this does not represent a field environment where the light is constantly changing.”

“In recent years, these dynamic processes have been thought to be more important, but they are not fully understood.”

In the new study, Dr. Burgess and his colleagues focused on poplar trees. Because poplar trees grow quickly and are great candidates for making biofuels and bioproducts.

They conducted a genome-wide association study (GWAS) by sampling approximately 1,000 trees in an outdoor research plot and analyzing their physical characteristics and genetic makeup.

The researchers used GWAS populations to search for candidate genes related to photosynthetic quenching. Photosynthetic quenching is the process that regulates how quickly plants adapt between sun and shade and dissipate excess energy from excessive sun to avoid damage.

One of the genes Booster (BSTR)was unusual because it is unique to poplar and contains sequences derived from chloroplasts, even though it is within the nuclear genome.

“We found that this gene can increase Rubisco content and subsequent photosynthetic activity, resulting in tall polar plants when grown in greenhouse conditions,” the authors said.

“In field conditions, we found that the genotypes were highly expressed. booster Up to 37% taller and more biomass per plant. ”

The researchers also booster at the model factory ArabidopsisAs a result, biomass and seed production increases.

This discovery is booster Can potentially cause yield increases in other plants.

“This is an exciting first step, but it is a small-scale experiment and there is much work to be done. If we can reproduce the results on a large scale, this gene has the potential to increase biomass production in crops.” said Dr. Burgess.

“Next steps in the research could include trials at other bioenergy and food plants, recording plant productivity under different growing conditions to analyze long-term success. .”

“We also plan to investigate other genes identified in the GWAS study that may contribute to crop improvement.”

of findings Featured in this week's diary developmental cells.

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Birk A. Feissa others. orphan gene booster Increases photosynthetic efficiency and plant productivity. developmental cellspublished online on December 3, 2024. doi: 10.1016/j.devcel.2024.11.002

Source: www.sci.news

Ancient microfossils indicate photosynthesis originated 1.75 billion years ago

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Oldest known evidence of photosynthetic structures identified in a collection of mysterious cylindrical microfossils Nabyfusa magensis It was discovered in the 1.75 billion year old McDermott Formation in Australia.

Nabyfusa magensis Microfossil: (a) Nabyfusa magensis From the McDermott Formation of the Tawala Supergroup, northern Australia. (b) Nabyfusa magensis From the Grassy Bay Formation of the Shaler Supergroup in the Canadian Arctic. (c) Nabyfusa magensis From the Mbujimai supergroup BIIc6 formation in the Democratic Republic of the Congo. Scale bar – 50 μm. Image credit: Demoulin other., doi: 10.1038/s41586-023-06896-7.

Oxygenic photosynthesis, in which sunlight catalyzes the conversion of water and carbon dioxide to glucose and oxygen, is unique to cyanobacteria and related organelles within eukaryotes.

Cyanobacteria played an important role in the evolution of early life and were active before the B.C. big oxidation event Approximately 2.4 billion years ago, the timing of the origin of oxygenic photosynthesis is debated due to limited evidence.

“Today, oxygenic photosynthesis is unique to cyanobacteria and their plastid relatives within eukaryotes,” said the paleontologist at the University of Liege. Catherine Dumoulin And her colleagues.

“Although its origins before the Great Oxidation Event are still debated, the accumulation of oxygen profoundly altered Earth's redox chemistry and the evolution of the biosphere, which contains complex life.”

“Understanding the diversification of cyanobacteria is therefore critical to understanding the coevolution of our planet and life, but their early fossil record remains equivocal.”

In their research, Demoulin and his co-authors discovered fossilized photosynthetic structures. Nabyfusa magensis Microfossil.

The microstructure is thylakoid. A membrane-bound structure found inside the chloroplasts of plants and some modern cyanobacteria.

Researchers identified them from fossils taken from three different locations, the oldest of which is from Australia's McDermott Formation and dates to 1.75 billion years ago (Paleoproterozoic era).

Nabyfusa magensis It is thought to be a cyanobacterium. The discovery of thylakoids in specimens from this period suggests that photosynthesis may have evolved at some point 1.75 billion years ago.

However, the mystery of whether photosynthesis evolved before or after the Great Oxidation Event remains unsolved.

Similar ultrastructural analyzes of older microfossils could help answer this question and determine whether the evolution of thylakoids contributed to elevated oxygen levels during the Great Oxidation Event.

“This discovery extends the thylakoid fossil record by at least 1.2 billion years and establishes a minimum age for the divergence of thylakoid cyanobacteria to be about 1.75 billion years ago,” the authors said. .

“This allows for the unambiguous identification of early oxygenic photosynthetic substances and new redox substances for investigating early Earth ecosystems, and for deciphering the paleontology and early evolution of fossil cells. This highlights the importance of examining the ultrastructure of cells.”

team's paper Published in today's magazine Nature.

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CF Dumoulin other. The oldest known fossil cells, thylakoids, provide direct evidence of oxygenic photosynthesis. Nature, published online on January 3, 2024. doi: 10.1038/s41586-023-06896-7

Source: www.sci.news

Fossils dating back 1.75 billion years shed new light on the evolution of photosynthesis

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Microscopic image of a modern cyanobacterium called Oscillatoria

Shutterstock / Ekki Ilham

Researchers have identified photosynthetic structures inside a 1.75 billion-year-old cyanobacteria fossil. This discovery is the oldest evidence yet of these structures and provides clues to how photosynthesis evolved.

Emmanuel Javeau Researchers from the University of Liège in Belgium analyzed fossils collected from rocks at three locations. The oldest site is the approximately 1.75 billion-year-old McDermott Formation in Australia, the other two are the billion-year-old Grassy Bay Formation in Canada and the Bllc6 Formation in the Democratic Republic of Congo. was.

From these rocks, the researchers extracted fossilized cyanobacteria that produce energy through photosynthesis. “They're so small, less than a millimeter, that you can't see them with the eye,” Java says. She and her colleagues placed the fossils in resin, sliced ​​them into sections 60 to 70 nanometers thick using a diamond-bladed knife, and analyzed their internal structures using an electron microscope.

They discovered that cyanobacteria in Australia and Canada contain thylakoids, membrane-enclosed sacs in which photosynthesis occurs. “These are the oldest fossilized thylakoids that we know of today,” Java says. Previously, the oldest thylakoid fossils were around 550 million years old. “So we delayed the fossil record by 1.2 billion years,” she says.

This is important because not all cyanobacteria have thylakoids and it is unclear when these structures, which make photosynthesis more efficient, first evolved, they said. Kevin Boyce at Stanford University in California. The origins of this diversification can now be traced back at least 1.75 billion years, he says. The oldest fossils of cyanobacteria are about 2 billion years old, but other evidence, such as geochemical signatures, indicate that photosynthesis has been around even longer than that.

It is widely believed that cyanobacteria helped build up oxygen in Earth's atmosphere 2.4 billion years ago. “The idea is that perhaps during this time they invented thylakoids, which increased the amount of oxygen on Earth,” Java says. “Now that we have discovered very old thylakoids and found them preserved in very old rocks, we think we might be able to test this hypothesis even further back in time,” she says. .

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Source: www.newscientist.com

Discovery of a ‘Quantum Switch’ Controlling Photosynthesis by Scientists

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A new study reveals the quantum switching mechanism of light-harvesting complex II (LHCII), which is critical for efficient photosynthesis. This discovery, achieved through advanced cryo-EM and theoretical calculations, supports a dynamic role for LHCII in regulating energy transfer in plants. Credit: SciTechDaily.com

Photosynthesis is an important process that allows plants to use sunlight to convert carbon dioxide into organic compounds. Light-harvesting complex II (LHCII) consists of dye molecules bound to proteins. It alternates between two main roles. Under strong light, excess energy is dissipated as heat through non-photochemical quenching, and under weak light, light is efficiently transferred to the reaction center.

Recent bioengineering research has revealed that faster switching between these functions can improve photosynthetic efficiency. For example, soybean crops showed yield increases of up to 33%. However, the precise atomic-level structural changes in LHCII that cause this control have not been known until now.

The molecular mechanism of NPQ and acidity-induced changes in several key structural factors cause the LHCII trimer to switch between light-harvesting and energy-quenching states.Credit: Institute of Physics

innovative research approach

In the new study, researchers led by Professor Weng Yuxiang from the Institute of Physics, Chinese Academy of Sciences, in collaboration with Professor Gao Jiali’s group from the Shenzhen Bay Institute, combined single-particle cryo-electron microscopy (cryo-EM) research. Using multistate density functional theory (MSDFT) calculations of energy transfer between photosynthetic pigment molecules, we analyzed the dynamic structure of his LHCII at atomic resolution and identified photosynthetic pigment quantum switches for intermolecular energy transfer. Masu.

As part of the study, they developed a series of six cryogenic states, including energy transfer states with LHCII in solution and energy quenching states with laterally confined LHCII in membrane nanodisks under neutral and acidic conditions. reported the EM structure.

Comparing these different structures shows that LHCII undergoes a structural change upon acidification. This change allosterically changes the interpigment distance of the fluorescence quenching locus lutein 1 (Lut1)-chlorophyll 612 (Chl612) only when LHCII is confined to membrane nanodiscs, leading to the quenching of excited Chl612 by Lut1. cause. Therefore, lateral pressure-confined LHCII (e.g., aggregated LHCII) is a prerequisite for non-photochemical quenching (NPQ), whereas acidThe induced conformational change enhances fluorescence quenching.

Cryo-EM structures of LHCII in nanodiscs and surfactant solutions at pH 7.8 and 5.4. Credit: Institute of Physics

Quantum switching mechanism in photosynthesis

Through cryo-EM structures and MSDFT calculations of known crystal structures in the extinction state and transient fluorescence experiments, an important quantum switching mechanism of LHCII with the Lut1-Chl612 distance as a key factor was revealed.

This distance controls the energy transfer quantum channels in response to lateral pressure and conformational changes to LHCII. That is, a small change in the critical distance of 5.6 Å allows a reversible switch between light collection and excess energy dissipation. This mechanism allows for rapid response to changes in light intensity, achieving both high efficiency and efficiency. photosynthesis Balanced photoprotection using LHCII as a quantum switch.

Fluorescence decay rate, relationship of Lut1–Chl612 electronic bond strength to Lut1–Chl612 separation distance, and plot of Lut1–Chl612 distance versus crossing angle of TM helices A and B in different LHCII structures. Credit: Institute of Physics

Previously, these two research groups collaborated on molecular dynamics simulations and ultrafast infrared spectroscopy experiments to propose that LHCII is an allosterically controlled molecular machine. Their current experimental cryo-EM structure confirms previously theoretically predicted structural changes in his LHCII.

Reference: “Cryo-EM structure of LHCII in photoactive and photoprotected states reveals allosteric control of light harvesting and excess energy dissipation” Meixia Ruan, Hao Li, Ying Zhang, Ruoqi Zhao, Jun Zhang, Yingjie Wang , Jiali Gao, Zhuan Wang, Yumei Wang, Dapeng Sun, Wei Ding, Yuxiang Weng, August 31, 2023, natural plants.
DOI: 10.1038/s41477-023-01500-2

This research was supported by a project of the Chinese Academy of Sciences, the National Natural Science Foundation of China, and the Shenzhen Science and Technology Innovation Committee.

Source: scitechdaily.com