Adapting to hypoxia: Zooplankton influence the efficiency of the biological carbon pump in the Humboldt Current

08.12.2023/Kiel. Marine organisms play a crucial role in the global carbon cycle. Phytoplankton absorb carbon dioxide from the atmosphere and sequester it in organic matter that sinks to the deep ocean where it can be stored for long periods of time. Until now, this process – the biological carbon pump – was thought to be particularly efficient in oxygen-poor areas. A new study by researchers at the GEOMAR Helmholtz Centre for Ocean Research Kiel suggests that the influence of certain zooplankton species on the biological carbon pump has been underestimated. The scientists have published their findings in the journal Communications Earth & Environment.

Quelle: IDW Informationsdienst Wissenschaft

Breathing poison: Microbial life on nitric oxide respiration

Nitric oxide (NO) is a central molecule in the global cycling of nitrogen, and also toxic. Little is known about if and how microbes can use NO as a substrate for growth. Scientists from the Max Planck Institute for Marine Microbiology in Bremen, Germany, have now managed to grow a microbial community dominated by two, so-far unknown species on NO for more than four years (and counting) and study their metabolism in great detail. Their research, now published in in Nature Microbiology, provides insight into the physiology of NO-reducing microorganisms, which have pivotal roles in the control of climate active gases, waste removal, and the evolution of nitrate and oxygen respiration.

Quelle: IDW Informationsdienst Wissenschaft

Scientists discover ‘lost world’ of our early ancestors in billion-year-old rocks

Newly discovered biomarker signatures point to a whole range of previously unknown organisms that dominated complex life on Earth about a billion years ago. They differed from complex eukaryotic life as we know it, such as animals, plants and algae in their cell structure and likely metabolism, which was adapted to a world that had far less oxygen in the atmosphere than today. Benjamin Nettersheim from the MARUM – Center for Marine Environmental Sciences, University of Bremen and Faculty of Geosciences at the University of Bremen and an international team of researchers now report on this breakthrough for the field of evolutionary geobiology in the journal Nature.

Quelle: IDW Informationsdienst Wissenschaft

Suffocating cancer cells: Self-assembling molecules could help in cancer therapy

Development of medical treatment against cancer is a major research topic worldwide – but cancer often manages to circumvent the solutions found. Scientists around Tanja Weil and David Ng at the Max Planck Institute for Polymer Research (MPI-P), have now taken a closer look at the cancer’s countermeasures and aim to stop them. By disrupting the cellular components that are responsible for converting oxygen into chemical energy, they have demonstrated initial success in eliminating cells derived from untreatable metastatic cancer.

Quelle: IDW Informationsdienst Wissenschaft

Protein folding in times of oxygen deficiency

Protein molecules require a defined shape in order to function. When they are created, their building blocks are therefore linked together in a very specific way. Researchers at the University of Bonn are now taking a closer look at a key step in this process and are investigating the effects of transient oxygen starvation on protein folding in plants. Researchers from the University of Münster, the Technical University of Kaiserslautern and the University of Bielefeld were also involved in the study. The study has now been published in the journal Plant Cell.

Quelle: IDW Informationsdienst Wissenschaft

Lessons from the past: how cold-water corals respond to global warming

New MARUM study: Food and oxygen have the greatest impact on survival.

Quelle: IDW Informationsdienst Wissenschaft

Microparticles with feeling

Watching corals breathe: Researchers develop a new method to simultaneously measure flow and oxygen.

An international research team headed by the Max Planck Institute for Marine Microbiology in Bremen, Aarhus University and the Science for Life Lab in Uppsala has developed tiny particles that measure the oxygen concentration in their surroundings. In this way, they can track fluid flow and oxygen content at the same time – exciting prospects for many fields of research, from biology to physics.

Quelle: IDW Informationsdienst Wissenschaft

CRISPR/Cas9 gene editing boosts effectiveness of ultrasound cancer therapy

Sonodynamic therapy uses ultrasound in combination with drugs to release harmful reactive oxygen species (ROS) at the site of a tumor. However, the treatment isn’t very effective because cancer cells can activate antioxidant defense systems to counteract it. Now, researchers have breached these defenses with CRISPR/Cas9 gene editing, allowing sonodynamic therapy to effectively shrink tumors in a mouse model of liver cancer.

Quelle: Sciencedaily

An estrogen receptor that promotes cancer also causes drug resistance

Cancer cells proliferate despite a myriad of stresses — from oxygen deprivation to chemotherapy — that would kill any ordinary cell. Now, researchers have gained insight into how they may be doing this through the downstream activity of a powerful estrogen receptor. The discovery offers clues to overcoming resistance to therapies like tamoxifen that are used in many types of breast cancer.

Quelle: Sciencedaily

A long day for microbes, and the rise of oxygen on Earth

Life on Earth today relies on the presence of oxygen. However, the process behind the step-wise rise of oxygen levels in the atmosphere, which took place over nearly two billion years, remains under debate. An international team of scientists around Judith Klatt from the Max Planck Institute for Marine Microbiology in Bremen, Germany, proposes an intriguing explanation: that increasing daylength, resulting from slowing Earth rotation, may have allowed microbes to release more oxygen, thereby creating the air we breathe today. They now present their result in Nature Geosciences.

Quelle: IDW Informationsdienst Wissenschaft

Sulfur enhances carbon storage in the Black Sea

Oldenburg study finds new explanation for why organic compounds accumulate in oxygen-depleted marine environments.

Quelle: IDW Informationsdienst Wissenschaft

New study may help explain low oxygen levels in COVID-19 patients

A new study sheds light on why many COVID-19 patients, even those not in hospital, are suffering from hypoxia — a potentially dangerous condition in which there is decreased oxygenation in the body’s tissues. The study also shows why the anti-inflammatory drug dexamethasone has been an effective treatment.

Quelle: Sciencedaily

New indicator for oxygen levels in early oceans developed

A geoscientific research team led by scientists from the University of Cologne has come a decisive step closer to determining the oxygen levels in the early Earth’s history by analysing the composition of tungsten isotopes / publication in PNAS

Quelle: IDW Informationsdienst Wissenschaft

How oxygen radicals protect against cancer

Oxygen radicals in the body are generally considered dangerous because they can trigger something called oxidative stress, which is associated with the development of many chronic diseases such as cancer and cardiovascular disease. In studies on mice, scientists have now discovered how oxygen radicals, conversely, can also reduce the risk of cancer and mitigate damage to the hereditary molecule DNA.

Quelle: Sciencedaily

News from geological history: How oxygen-producing cyanobacteria facilitated complex life

The „Great Oxygenation Event“ (GOE), the process whereby the Earth’s atmosphere was continuously enriched with oxygen, a waste product of photosynthesis, began ~2.43 billion years ago. The source, according to science, was photosynthesizing cyanobacteria. But why did this all-important turnaround occur so late? Cyanobacterial life existed, as rock samples show, at least 300 million years before the GOE. Achim Herrmann, who is researching the spread of early cyanobacteria in his doctoral thesis at TU Kaiserslautern, is hot on the trail for answers. His current research paper has now been published in the journal Nature Communications.

Quelle: IDW Informationsdienst Wissenschaft

Reliably Measuring Whether Rivers or Lakes Run Out of Air

Wastewater carries large quantities of organic substances into the rivers and lakes, leading to heavy growth of bacteria and oxygen deficiency. Measurement methods have so far been incapable of measuring this organic pollution precisely. A new method co-developed by experts from the Helmholtz-Zentrum Hereon should provide a clear image of the water conditions in the future. The work has now been published in the scientific journal Science Advances.

Quelle: IDW Informationsdienst Wissenschaft

New form of symbiosis discovered

They are also called power plants of the cells: the mitochondria. They are present in almost all eukaryotic cells and they supply the cells with energy. Until now, it was assumed that only mitochondria can act as the cells’ energy providers. Scientists at the Max Planck Institute for Marine Microbiology have now discovered that symbiotic bacteria can fulfil this function too. Their findings shed a completely new light on the survival of simple eukaryotes in oxygen-free environments. These results have just been published in the renowned scientific journal Nature.

Quelle: IDW Informationsdienst Wissenschaft

Photosynthetic bacteria-based cancer optotheranostics

Natural purple photosynthetic bacteria (PPSB) can play a key role as a highly active cancer immunotheranostics agent that uses the bio-optical-window I and II near-infrared (NIR) light. PPSB have high tumor specificity and non-pathogenicity. Active anticancer efficacy and powerful multi-functions such as NIR-I-to-NIR-II fluorescence, photothermal conversion, reactive oxygen species generation, and contrasty photoacoustic effect, can be expressed using NIR light exposure to PPSB.

Quelle: Sciencedaily

The carcinogenic effect of various multi-walled carbon nanotubes (MWCNTs) after intraperitoneal injection in rats

Non-neoplastic histopathological findings in the abdominal cavity. A: High-power view of anti-podoplanin immunohistochemistry showing single MWCNT A (high dose) nanotubes in the tissue (arrows). B: High-power view of anti-podoplanin immunohistochemistry showing single asbestos fibers in the tissue (arrows). C: H & E, high-power view of granuloma induced by MWCNT A (low dose) nanotubes including single nanotube (arrow, 25×). D: H & E, high-power view of granuloma induced by asbestos including single fiber (arrow, 40×). Rittinghausen et al. Particle and Fibre Toxicology 2014 11:59 doi:10.1186/s12989-014-0059-z — Non-neoplastic histopathological findings in the abdominal cavity. A: High-power view of anti-podoplanin immunohistochemistry showing single MWCNT A (high dose) nanotubes in the tissue (arrows). B: High-power view of anti-podoplanin immunohistochemistry showing single asbestos fibers in the tissue (arrows). C: H & E, high-power view of granuloma induced by MWCNT A (low dose) nanotubes including single nanotube (arrow, 25×). D: H & E, high-power view of granuloma induced by asbestos including single fiber (arrow, 40×).
Rittinghausen et al. Particle and Fibre Toxicology 2014 11:59 doi:10.1186/s12989-014-0059-z

Susanne Rittinghausen, Anja Hackbarth, Otto Creutzenberg, Heinrich Ernst, Uwe Heinrich, Albrecht Leonhardt and Dirk Schaudien

Abstract

Background

Biological effects of tailor-made multi-walled carbon nanotubes (MWCNTs) without functionalization were investigated in vivo in a two-year carcinogenicity study. In the past, intraperitoneal carcinogenicity studies in rats using biopersistent granular dusts had always been negative, whereas a number of such studies with different asbestos fibers had shown tumor induction. The aim of this study was to identify possible carcinogenic effects of MWCNTs. We compared induced tumors with asbestos-induced mesotheliomas and evaluated their relevance for humans by immunohistochemical methods.

Methods

A total of 500 male Wistar rats (50 per group) were treated once by intraperitoneal injection with 10⁹ or 5 × 10⁹ WHO carbon nanotubes of one of four different MWCNTs suspended in artificial lung medium, which was also used as negative control. Amosite asbestos (10⁸ WHO fibers) served as positive control. Morbid rats were sacrificed and necropsy comprising all organs was performed. Histopathological classification of tumors and, additionally, immunohistochemistry were conducted for podoplanin, pan-cytokeratin, and vimentin to compare induced tumors with malignant mesotheliomas occurring in humans.

Results

Treatments induced tumors in all dose groups, but incidences and times to tumor differed between groups. Most tumors were histologically and immunohistochemically classified as malignant mesotheliomas, revealing a predominantly superficial spread on the serosal surface of the abdominal cavity. Furthermore, most tumors showed invasion of peritoneal organs, especially the diaphragm. All tested MWCNT types caused mesotheliomas. We observed highest frequencies and earliest appearances after treatment with the rather straight MWCNT types A and B. In the MWCNT C groups, first appearances of morbid mesothelioma-bearing rats were only slightly later. Later during the two-year study, we found mesotheliomas also in rats treated with MWCNT D – the most curved type of nanotubes. Malignant mesotheliomas induced by intraperitoneal injection of different MWCNTs and of asbestos were histopathologically and immunohistochemically similar, also compared with mesotheliomas in man, suggesting similar pathogenesis.

Conclusion

We showed a carcinogenic effect for all tested MWCNTs. Besides aspect ratio, curvature seems to be an important parameter influencing the carcinogenicity of MWCNTs.

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Schlagwort: oxygen