Karl Heinz Rechinger — a Grand Old Man in botany

A brief survey and appreciation ofK. H. Rechinger's manifold activities is given on the occasion of his 80th birthday—as plant taxonomist, phyto-geographer specializing in the flora of Greece and SW. Asia, author of Flora Aegaea and editor of Flora Iranica, plant collector, head of the Department of Botany and later Director-General of the Natural History Museum in Vienna and as academic teacher at Vienna University.English version of a speech given in the Institute of Botany, University of Vienna on October 18th, 1986 on the occasion ofK. H. Rechinger's 80th birthday.     

The path to life’s origins. Remaining hurdles

Recent progress in abiotic syntheses, especially self-catalytic syntheses, as well as theoretical breakthroughs such as reconstruction of events of early molecular evolution and tracing repeat expansions in contemporary genomes, converge to a rather simple possible scenario of origin of life, notwithstanding the enormity of the problem. The scenario includes self-replicating RNA duplexes, supplemented by monomers and high-energy compounds that, as demonstrated or assumed, can all be synthesized abiotically. The self-replication would proceed with occasional mutational changes, propagated in later cycles. This audacious, as it may seem, walk toward the life origin already involves many laboratories, each exploring its own scenario. The one suggested in this outline seems to the authors well justified to engage in, while bypassing few steps to deal with later.     

A taxonomic study on the genus LeptolepidiumK. H. Shing et S. K. Wu

A taxonomic study is made on the genus Leptolepidium K. H. Shing et S. K. Wu （Sinopteridaceae） on the basis of field work and specimen examination. Two species （L. caesium (Christ) K. H. Shing et S. K. Wu and L. tenellum Ching et S. K. Wu） and two va     

Solenostoma oblongifolium (K. Müll.) K. Müll. in Scotland—new to the British Isles

Abstract

To determine the responses of cryptogams to the variations in temperature, pH, and humidity, we studied the vegetation of Thermal Meadow, Hotsprings Island, Queen Charlotte Islands, B.C., Canada. Only seven cryptogamic taxa were present in the samples: five mosses, one liverwort, and one lichen. Humidity limited the distribution, with Racomitrium lanuginosum and Cladina ciliata preferring the warmer, drier sites and Pleurozium schreberi and Dicranum scoparium preferring cooler, more moist sites. Polytrichum formosum was the most frequent taxon, occurring under both cool, moist conditions and warm, dry conditions. Aulacomnium palustre occurred in the mid temperature range mostly where humidity was fairly high. The pH ranged 6.8–7.2, providing insufficient variation for us to delimit species preferences.     

Electron microscopy—The U.K. involvement

The development of the electron microscope in the advanced form we know today is the result of a loosely organized but effective world-wide scientific and technological collaboration, that readily transcends national and cultural barriers. The birth of the subject was undoubtedly in Berlin but the United Kingdom has played a prominent part, sometimes in an accidental way, at critical periods in this development both at the scientific and manufacturing level. In 1927, for example, G.P. Thompson established experimentally the wave nature of the electron and its scattering and diffraction by thin foils. This followed his invention of the electron diffraction camera at a time when De Broglie's postulates on the wave of nature of the electron were not enjoying much support, even in his native France. C.W. Oatley in Cambridge University was successful in introducing the first commercial scanning electron microscope (SEM) where several commercial firms had previously failed. D. Gabor invented electron holography in a moment of boredom while watching a tennis match. The U.K. has also played a key role in fostering international collaboration by means of conferences and exchange visits between electron microscopists. The present paper concentrates on some of the critical developments that took place in the U.K. in the commercial development of transmission electron microscopy, in scanning electron microscopy and more recently in high resolution electron microscopy. These developments are placed as far as possible in a world-wide context.     

Binding of histamine to the H1 receptor—a molecular dynamics study

Binding of histamine to the G-protein coupled histamine H₁ receptor plays an important role in the context of allergic reactions; however, no crystal structure of the resulting complex is available yet. To deduce the histamine binding site, we performed unbiased molecular dynamics (MD) simulations on a microsecond time scale, which allowed to monitor one binding event, in which particularly the residues of the extracellular loop 2 were involved in the initial recognition process. The final histamine binding pose in the orthosteric pocket is characterized by interactions with Asp107^3.32, Tyr108^3.33, Thr194^5.43, Asn198^5.46, Trp428^6.48, Tyr431^6.51, Phe432^6.52, and Phe435^6.55, which is in agreement with existing mutational data. The conformational stability of the obtained complex structure was subsequently confirmed in 2 μs equilibrium MD simulations, and a metadynamics simulation proved that the detected binding site represents an energy minimum. A complementary investigation of a D107A mutant, which has experimentally been shown to abolish ligand binding, revealed that this exchange results in a significantly weaker interaction and enhanced ligand dynamics. This finding underlines the importance of the electrostatic interaction between the histamine ammonium group and the side chain of Asp107^3.32 for histamine binding.     

Plant Morphogenesis 123: a renaissance in modern botany?

Plants are a group of multicellular organisms crucial for the biosphere on the Earth. In the 17th century, the founding fathers of modern botany viewed the bud as the basic unit undergoing the plant life cycle. However, for many understandable reasons, the dominant conceptual framework evolved away from the “bud-centered” viewpoint to a “plant-centered” viewpoint that treated the whole plant, consisting of numerous buds, as a unit and considered the entire plant to be the functional equivalent of an animal individual. While this “plant-centered” viewpoint is convenient and great progress has been made using this conceptual framework, some fundamental problems remain logically unsolvable. Previously, I have proposed a new conceptual framework for interpretation of plant morphogenesis, called Plant Morphogenesis 123, which revives a “bud-centered” viewpoint. The perspective of Plant Morphogenesis 123 allows us to address new questions regarding to the mechanisms of plant morphogenesis that are important, and technically accessible, but previously neglected under the “plant-centered” conceptual framework. In addition to describing these questions, I address a more fundamental question for further discussion: why do people study plants?

     

Simmondsia or Jojoba—A problem in economic botany

This desert shrub of the American Southwest offers an unusual and as yet undeveloped source of a valuable liquid wax The principal problem m its commercial exploitation is that of cultivating the plants.