Phacopsis — A lichenicolous genus of the family Parmeliaceae

SSU nrDNA studies of two representatives of the lichenicolous genus Phacopsis revealed that they belong to the family Parmeliaceae (Lecanorales) and therefore represent lichenicolous lichens with an endokapylic thallus. Because they are the only lichenicolous taxa within this family, it is suggested that their transition from a foliose and/or fruticose precursor lichen might have been due to a unique (or rare) evolutionary one step event(s). Phylogenetic analyses of the ITS nrDNA of the type species of Phacopsis (P. vulpina) and Nesolechia (N. oxyspora = P. oxyspora) could neither confirm nor reject a monophyletic origin of these two Parmeliacean genera, as previously implied by their synonymization. However, it is considered premature to draw nomenclatorial consequences.     

Biodegradation of 1,2,3-Trichloropropane through Directed Evolution and Heterologous Expression of a Haloalkane Dehalogenase Gene

Using a combined strategy of random mutagenesis of haloalkane dehalogenase and genetic engineering of a chloropropanol-utilizing bacterium, we constructed an organism that is capable of growth on 1,2,3-trichloropropane (TCP). This highly toxic and recalcitrant compound is a waste product generated from the manufacture of the industrial chemical epichlorohydrin. Attempts to select and enrich bacterial cultures that can degrade TCP from environmental samples have repeatedly been unsuccessful, prohibiting the development of a biological process for groundwater treatment. The critical step in the aerobic degradation of TCP is the initial dehalogenation to 2,3-dichloro-1-propanol. We used random mutagenesis and screening on eosin-methylene blue agar plates to improve the activity on TCP of the haloalkane dehalogenase from Rhodococcus sp. m15-3 (DhaA). A second-generation mutant containing two amino acid substitutions, Cys176Tyr and Tyr273Phe, was nearly eight times more efficient in dehalogenating TCP than wild-type dehalogenase. Molecular modeling of the mutant dehalogenase indicated that the Cys176Tyr mutation has a global effect on the active-site structure, allowing a more productive binding of TCP within the active site, which was further fine tuned by Tyr273Phe. The evolved haloalkane dehalogenase was expressed under control of a constitutive promoter in the 2,3-dichloro-1-propanol-utilizing bacterium Agrobacterium radiobacter AD1, and the resulting strain was able to utilize TCP as the sole carbon and energy source. These results demonstrated that directed evolution of a key catabolic enzyme and its subsequent recruitment by a suitable host organism can be used for the construction of bacteria for the degradation of a toxic and environmentally recalcitrant chemical.     

Molecular evolution of carotenoid biosynthesis from bacteria to plants

β-Carotene and derivatives are important pigments in plant photosynthesis. They are found not only in green plants but also accumulate in archea, prokaryotes and fungi. For β -carotene biosynthesis, enzymes are necessary to catalyse the formation of phytoene, several desaturation steps and cyclization reactions. This review is focused on the molecular phylogeny of the enzymes, the genes involved and their diversity. It outlines how genes and enzymes from prokaryotes and archea were modified to give rise to the corresponding plant constituents. In the cases of phytoene synthase, a direct line of evolution can be drawn. For other carotenogenic enzymes, new genes and enzymes have been acquired at certain stages of evolution. In addition, phytoene desaturases and lycopene cyclases are examples of convergent evolution of different types of enzymes, which are structurally completely unrelated but functionally identical. Finally, several gene duplications led to homologous enzymes with different catalytic functions including those involved in the synthesis of α -carotene.     

Preface

Since the recent growth of molecular and genetic methods, and their implementation into organismic biology, zoology has been slowly regaining the importance it enjoyed until the late 1970's. Biologists are becoming increasingly aware that dynamic processes between molecules and proteins, the products of expressed genes, are relevant in the context of the whole organism's physiological status and behaviour. This modernization of organismic biology, however, has also resulted in more differentiation and diversity of methods within the disciplines that apply to the animal sciences. This increasing diversity within zoological disciplines was highlighted in the series of lectures held at our annual meeting in Halle in 2002.The highlight of the Halle meeting was undoubtedly the awarding of the Karl von Frisch Prize to F. G. Barth from Vienna University. Since Karl von Frisch's work few have so successfully exemplified the wealth of knowledge and insights that may be gained by applying modern methods, and convergent approaches from different disciplines to one single species. Barth's work focused on the wandering spiders Cupiennius. His lecture, “spider senses – technical perfection and biology” demonstrated to us the scientific power of a holistic approach.In the context of the behavioural studies of our colleagues at Halle University, Charlotte Helfrich-Förster presented a survey of “The circadian system of Drosphila melanogaster and its light input pattern”. Behavioural research on rhythms has its roots in Germany and enjoys a long tradition in zoology. As in many other disciplines, modern genetics opened up new and very fruitful insights into the subject.A greater understanding of the mechanisms of learning and memory is another field of research that has benefitted greatly from molecular biology. It has become a flourishing and expanding area of research, especially in invertebrate zoology. The current state of research, from a neurobiological and molecular point of view, was presented in three lectures, including one by Uli Müller, of the Berlin School. Cognition in audition, a still emerging field, was introduced to us in Bernhard Gaese's lecture on “Precognitive and cognitive elements in sound localization”. In the future, auditory cognition will surely become a Dorado for neurobiologists and acoustic psychologists. Susan D. Healy connected cognition with ecological constraints in her talk “Animal learning and memory: an integration of cognition and ecology”. She argued that cognitive performances can only be explained in the context of species-specific behaviours and ecology. “Cognitive ecology”, as it may be termed, is an emerging and genuinely zoological field of research that will have an important impact on our understanding of evolution. It's challenges will require highly motivated young zoologists.Research on species diversity takes a different approach to the subject of evolution and diversity, investigating the preconditions for speciation processes, and evolutionary trends and mechanisms. Unfortunately the fauna of soils is rarely considered, in spite of its great importance to ecological conditions. Richard Bagdett made up for this neglect in his lecture on the “Causes and consequences of biological diversity in soil”, and Bernhard Misof reported on speciation processes in Anisoptera.“Classical” physiology is still the backbone of organismic research. Modern versions of two very different topics were presented in Halle. Stephan Huber reported on the “Development of renal function”, and Fritz-Olaf Lehmann presented a new and convincing concept of aerodynamics and energetics in insect flight. His research continues the worthwhile tradition of flight analysis founded by Werner Nachtigall.The topics of our annual meeting in Halle could hardly have been more diverse. However, it is this the very diversity of modern and productive research field in zoology that characterizes a promising and fascinating future. In zoology, more than in any other biological discipline, exciting problems relevant to the understanding of evolution and its mechanisms are waiting to be solved by young scientists. Zoology has again become a start-up enterprise with promising rewards.     

Structural Requirements for Cub Domain Containing Protein 1 (CDCP1) and Src Dependent Cell Transformation

Cub domain containing protein 1 (CDCP1) is strongly expressed in tumors derived from lung, colon, ovary, or kidney. It is a membrane protein that is phosphorylated and then bound by Src family kinases. Although expression and phosphorylation of CDCP1 have been investigated in many tumor cell lines, the CDCP1 features responsible for transformation have not been fully evaluated. This is in part due to the lack of an experimental system in which cellular transformation depends on expression of exogenous CDCP1 and Src. Here we use retrovirus mediated co-overexpression of c-Src and CDCP1 to induce focus formation of NIH3T3 cells. Employing different mutants of CDCP1 we show that for a full transformation capacity, the intact amino- and carboxy-termini of CDCP1 are essential. Mutation of any of the core intracellular tyrosine residues (Y734, Y743, or Y762) abolished transformation, and mutation of a palmitoylation motif (C689,690G) strongly reduced it. Src kinase binding to CDCP1 was not required since Src with a defective SH2 domain generated even more CDCP1 dependent foci whereas Src myristoylation was necessary. Taken together, the focus formation assay allowed us to define structural requirements of CDCP1/Src dependent transformation and to characterize the interaction of CDCP1 and Src.     

A 14-kDa Schistosoma mansoni polypeptide is homologous to a gene family of fatty acid binding proteins

The complete nucleotide sequence encoding a Schistosoma mansoni protein termed Sm14 was determined from cDNA clones propagated in bacteriophage lambda gt11 in Escherichia coli. The 14.8-kDa protein bears significant homologies with a family of related polypeptides which bind hydrophobic ligands. Members of this group of cytosolic proteins were originally identified based on their affinity for long chain fatty acids. The purified recombinant protein exhibited an affinity to fatty acids, in contrast to a mutant lacking 16 N-terminal amino acids. Immunofluorescence experiments show that tubercles, which are structures located on the dorsal surface of adult male schistosome and known to contain lipids, are stained using antibodies raised to the beta-galactosidase fusion protein. A regular staining pattern is also evident in the muscle layers as well as in the body of the parasite. As the schistosome cannot synthesize fatty acids de novo and is dependent on the uptake of lipids from serum, the available data support a role for Sm14 in the transport of fatty acids.