Hartmut K. Lichtenthaler (born 20 June 1934 in Weinheim, Germany) is a German botanist, plant physiologist and university professor. [1]
Contents
Hartmut K. Lichtenthaler (born 20 June 1934 in Weinheim, Germany) is a German botanist, plant physiologist and university professor. [1]
Hartmut Lichtenthaler studied pharmacy, biology and chemistry at the University of Karlsruhe (TH). In 1958, he completed his studies with the pharmaceutical state examination in Germany ('Staatsexamen'). In 1961, he earned his Ph.D. at the University of Heidelberg with a dissertation about vitamin K1 in plants at the institute of Professor August Seybold. [2] In the period 1962–1964, he was a research fellow at the laboratory of Nobel laureate Melvin Calvin at the University of California, Berkeley. [2] In 1964, he became an assistant professor at the University of Münster, where he completed his Habilitation in 1967 with a thesis about prenylquinones and osmiophilic plastoglobuli in chloroplasts. In 1970, he became a full professor for plant physiology, plant biochemistry and pharmaceutical biology at the University of Karlsruhe, Germany. Lichtenthaler developed his institute to a research center for photosynthesis, isoprenoid biochemistry and fluorescence imaging. [3] In 2001, he became professor emeritus. [4]
Lichtenthaler’s research fields are the photosynthesis of green plants, the light adaptation, pigment composition, photosynthetic function and ultrastructure of chloroplasts, the regulation of the plants’ isoprenoid biosynthesis, as well as the laser-induced fluorescence imaging of photosynthetic activity and of stress-detection in plants. [2] He is known for establishing the non-mevalonate desoxyxylulose-phosphate / methylerythritol phosphate pathway (DOXP / MEP pathway) of isoprenoid biosynthesis in chloroplasts. [3] The latter, which is responsible for the biosynthesis of carotenoids, prenyl-quinones, isoprene, mono- and diterpenes was detected in the 1990s (via 13C-labelling + NMR-spectroscopy) in close cooperation with Michel Rohmer. Lichtenthaler also showed that the DOXP/MEP-pathway not only occurs in all photosynthetic organisms (plants, algae, photosynthetic bacteria), but also in pathogenic bacteria und the malaria parasite Plasmodium falciparum. He developed a plant-based test-system to find new drugs against malaria. [2]
Lichtenthaler's scientific activities yielded 6 books and more than 410 publications in scientific journals. He was guest professor at the University of Gothenburg (1975) and University of Lancaster (1981). He promoted international scientific collaboration, organized many conferences and workshops and promoted young scientists. [2] In 1978, Lichtenthaler was a co-founder of the Federation of European Societies of Plant Physiology (FESPP), and he acted from 1984–1986 as FESPP president. [5] In 1988, he managed that – despite initial obstructions by the political authorities – the East European researchers from Russia, Hungary, the Czech Republic and East-Germany could become members of the European federation FESPP. [2] Lichtenthaler also described the history and development of botanical co-operations, such as FESPP, and that of international symposia series and workshops in plant physiology [6] and plant biochemistry. [7]
Hartmut Lichtenthaler received multiple honors and awards, including among others [2]
Lichtenthaler has about 420 publications (original papers, reviews) in international scientific journals and books, [4] including:
Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words χλωρός, khloros and φύλλον, phyllon ("leaf"). Chlorophyll allow plants to absorb energy from light.
Photosynthesis is a biological process used by many cellular organisms to convert light energy into chemical energy, which is stored in organic compounds that can later be metabolized through cellular respiration to fuel the organism's activities. The term usually refers to oxygenic photosynthesis, where oxygen is produced as a byproduct and some of the chemical energy produced is stored in carbohydrate molecules such as sugars, starch, glycogen and cellulose, which are synthesized from endergonic reaction of carbon dioxide with water. Most plants, algae and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the biological energy necessary for complex life on Earth.
The mevalonate pathway, also known as the isoprenoid pathway or HMG-CoA reductase pathway is an essential metabolic pathway present in eukaryotes, archaea, and some bacteria. The pathway produces two five-carbon building blocks called isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are used to make isoprenoids, a diverse class of over 30,000 biomolecules such as cholesterol, vitamin K, coenzyme Q10, and all steroid hormones.
Plastoquinone (PQ) is a terpenoid-quinone (meroterpenoid) molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4-benzoquinone molecule with a side chain of nine isoprenyl units. There are other forms of plastoquinone, such as ones with shorter side chains like PQ-3 as well as analogs such as PQ-B, PQ-C, and PQ-D, which differ in their side chains. The benzoquinone and isoprenyl units are both nonpolar, anchoring the molecule within the inner section of a lipid bilayer, where the hydrophobic tails are usually found.
Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light, and it is a poor absorber of green and near-green portions of the spectrum. Chlorophyll does not reflect light but chlorophyll-containing tissues appear green because green light is diffusively reflected by structures like cell walls. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria and prochlorophytes because of its role as primary electron donor in the electron transport chain. Chlorophyll a also transfers resonance energy in the antenna complex, ending in the reaction center where specific chlorophylls P680 and P700 are located.
Hartmut Michel is a German biochemist, who received the 1988 Nobel Prize in Chemistry for determination of the first crystal structure of an integral membrane protein, a membrane-bound complex of proteins and co-factors that is essential to photosynthesis.
A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and pheophytin, as well as quinones. The energy of the photon is used to excite an electron of a pigment. The free energy created is then used, via a chain of nearby electron acceptors, for a transfer of hydrogen atoms (as protons and electrons) from H2O or hydrogen sulfide towards carbon dioxide, eventually producing glucose. These electron transfer steps ultimately result in the conversion of the energy of photons to chemical energy.
The photosynthetic efficiency is the fraction of light energy converted into chemical energy during photosynthesis in green plants and algae. Photosynthesis can be described by the simplified chemical reaction
(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP or HMB-PP) is an intermediate of the MEP pathway (non-mevalonate pathway) of isoprenoid biosynthesis. The enzyme HMB-PP synthase (GcpE, IspG) catalyzes the conversion of 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP) into HMB-PP. HMB-PP is then converted further to isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) by HMB-PP reductase (LytB, IspH).
The non-mevalonate pathway—also appearing as the mevalonate-independent pathway and the 2-C-methyl-D-erythritol 4-phosphate/1-deoxy-D-xylulose 5-phosphate (MEP/DOXP) pathway—is an alternative metabolic pathway for the biosynthesis of the isoprenoid precursors isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). The currently preferred name for this pathway is the MEP pathway, since MEP is the first committed metabolite on the route to IPP.
Isopentenyl pyrophosphate isomerase, also known as Isopentenyl-diphosphate delta isomerase, is an isomerase that catalyzes the conversion of the relatively un-reactive isopentenyl pyrophosphate (IPP) to the more-reactive electrophile dimethylallyl pyrophosphate (DMAPP). This isomerization is a key step in the biosynthesis of isoprenoids through the mevalonate pathway and the MEP pathway.
Diphosphomevalonate decarboxylase (EC 4.1.1.33), most commonly referred to in scientific literature as mevalonate diphosphate decarboxylase, is an enzyme that catalyzes the chemical reaction
Rhodobacter sphaeroides is a kind of purple bacterium; a group of bacteria that can obtain energy through photosynthesis. Its best growth conditions are anaerobic phototrophy and aerobic chemoheterotrophy in the absence of light. R. sphaeroides is also able to fix nitrogen. It is remarkably metabolically diverse, as it is able to grow heterotrophically via fermentation and aerobic and anaerobic respiration. Such a metabolic versatility has motivated the investigation of R. sphaeroides as a microbial cell factory for biotechnological applications.
2-C-Methyl-d-erythritol-2,4-cyclopyrophosphate (MEcPP) is an intermediate in the MEP pathway (non-mevalonate) of isoprenoid precursor biosynthesis. MEcPP is produced by MEcPP synthase (IspF) and is a substrate for HMB-PP synthase (IspG).
Chlorophyll fluorescence is light re-emitted by chlorophyll molecules during return from excited to non-excited states. It is used as an indicator of photosynthetic energy conversion in plants, algae and bacteria. Excited chlorophyll dissipates the absorbed light energy by driving photosynthesis, as heat in non-photochemical quenching or by emission as fluorescence radiation. As these processes are complementary processes, the analysis of chlorophyll fluorescence is an important tool in plant research with a wide spectrum of applications.
Chlororespiration is a respiratory process that takes place within plants. Inside plant cells there is an organelle called the chloroplast which is surrounded by the thylakoid membrane. This membrane contains an enzyme called NAD(P)H dehydrogenase which transfers electrons in a linear chain to oxygen molecules. This electron transport chain (ETC) within the chloroplast also interacts with those in the mitochondria where respiration takes place. Photosynthesis is also a process that Chlororespiration interacts with. If photosynthesis is inhibited by environmental stressors like water deficit, increased heat, and/or increased/decreased light exposure, or even chilling stress then chlororespiration is one of the crucial ways that plants use to compensate for chemical energy synthesis.
André Tridon Jagendorf was an American Liberty Hyde Bailey Professor Emeritus in the Section of Plant Biology at Cornell University who is notable for providing direct evidence that chloroplasts synthesize adenosine triphosphate (ATP) using the chemiosmotic mechanism proposed by Peter Mitchell.
Thomas D. Sharkey is a plant biochemist who studies gas exchange between plants and the atmosphere. His research has covered (1) carbon metabolism of photosynthesis from carbon dioxide uptake to carbon export from the Calvin-Benson Cycle, (2) isoprene emission from plants, and (3) abiotic stress tolerance. Four guiding questions are: (1) how leaf photosynthesis affects plant yield, (2) does some carbon fixation follow an oxidative pathway that reduces sugar output but stabilizes photosynthesis, (3) why plants make isoprene, and (4) how plants cope with high temperature.
Roland Douce was a plant biologist and professor who, along with his students, created a world-renowned plant biology centre in Grenoble, France, focusing on the biology of chloroplasts and mitochondria and their roles in plant metabolism under normal or stressed physiological conditions.
Michel Rohmer, born on 31 January 1948, is a French chemist specialising in the chemistry of micro-organisms. He has particularly studied isoprenoids.
| International | |
|---|---|
| National | |
| Academics | |
| People | |
| Other | |
