Blockade des Gibberellinsäure-Transports in Hypocotylsegmenten durch Trijodbenzoesäure. Zugleich ein Neuer Agarblocktest auf Gibberelline

Summary Gibberellic acid (GA) was incubated in agar blocks, transported through hypocotyl sections of sunflower plants, and collected in acceptor blocks of plain agar. The amount of GA transported through the sections was tested with dwarf pea plants using a new test method in which the acceptor block was applied directly to the test plant. The GA transport was significantly lower through hypocotyl section from plants which had been treated with triiodobenzoic acid (TIBA) before isolation of the sections. TIBA inhibits the transport of GA.

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Herrn Prof. Dr. Dr. h. c.Hermann von Guttenberg zum 80. Geburtstag.     

Quantitation of hepatic sinusoidal macrophages during the acute systemic inflammatory reaction in two animal species

The participation of hepatic sinusoidal macrophages (HSM) in hepatocyte stimulation during the acute systemic inflammatory reaction has been suggested by recent in vitro investigations. A first attempt in studying the role of these cells in vivo would appear to be the quantitation of HSM at the different times of the inflammatory response, in order to determine whether the participation of HSM depends on the recruitment of blood monocytes to the liver or on the proliferation of resident cells. HSM were counted during the initial stages (0, 16, and 24 hr) of a turpentine-induced inflammation in the rat and the rabbit. They were identified on morphological grounds and were counted separately in the periportal and the perivenous areas of the hepatic lobule. No significant differences were found in the number of HSM per field at 0, 16, and 24 hr following the induction of inflammation. No variation in the distribution of these cells within the lobule could be detected during this period. These results do not support the hypothesis that the acute phase reaction is accompanied by an influx into the liver of newly recruited macrophages or by the proliferation of resident cells. Thus, if a commitment of HSM occurs in vivo during the acute systemic inflammation, it may depend on the activation of resident cells.     

B cell heterogeneity—Difference in the size of B lymphocytes responding to T dependent and T independent antigens

Spleen cells from either normal (nonimmunized) mice or mice preimmunized with TNP KLH were depleted of T cells by treatment with a heterologous anti θ serum and complement. Fractionation of these B cells by velocity sedimentation followed by challenge with either a T independent antigen (DNP POL) or a T dependent antigen (TNP KLH), the latter being performed in the presence of additional helper T cells, revealed apparent size difference between B cells responding to the two antigens. This difference, while most marked with preimmunized B cells, was also apparent with normal B cells from the spleen or bone marrow, but not from the lymph node. Similar data were observed with other T dependent and T independent antigens. The differences in the sedimentation profile of splenic B cells for T dependent and T independent antigens did not seem to be due to a difference in the kinetics of appearance of antibody upon stimulation with these antigens, though large B cells did seem to give rise to antibody producing cells at later times than small B cells.     

FUS: a system to simulate conformational changes in biological macromolecules

In order to study the dynamics of protein and nucleic acid conformations,a molecular folding-unfolding system (FUS written in Lisp) hasbeen developed. Secondary structure features of protein andnucleic acids are graphically represented by cubes in a modified‘Blocks World’ paradigm. Modeling of protein andnucleic acid unfolding (denaturation) and folding of their three-dimensionalstructure is possible by the use of high level ‘block’operators which allow displacement of these structural featuresin space. Due to the flexible nature of this program, FUS isa useful tool for the rapid evaluation of user-defined rulesgoverning conformational changes. The use of FUS to unfold threecommon proteins (prealbumin, flavodoxin and triose phosphateisomerase) and a tRNA is presented. Received on March 22, 1988; accepted on June 1, 1988     

The social fabric of citizen science—drivers for long-term engagement in the German butterfly monitoring scheme

Insect conservation needs sound information on species distribution trends. Developing this evidence relies—in practice—on long-term engagement of volunteers who observe and record species over large spatial and temporal scales. Many biodiversity monitoring schemes, including those for insects, are highly dependent on conservation-based citizen science programs with a long-term continuity. As these schemes are built entirely on good will, the nature of social relations and networks is pivotal to success. We assess the working mechanism of a monitoring scheme that is citizen-based as a case study. The German Butterfly Monitoring Scheme (hereafter TMD for “Tagfalter-Monitoring Deutschland”) operates, as many other citizen science monitoring schemes, through an overarching national network of regional subnetworks of volunteers and a central scientific coordination. Using a questionnaire survey paired with a visual social network assessment, we investigate how participants interact within these networks and assess their motivations to engage. We characterise the functionality of this social network based on mechanism of coordination and participation, flows of information and knowledge exchange among recorders, regional and central coordinators, academic scientists and institutions. By analyzing the interactions, we show how the social network facilitates and ensures various communication modes and thereby fosters long-term engagement, stability and growth of the scheme. We identify the central role of project coordination and the importance of social relations within citizen-based monitoring programs for engagement and personal satisfaction. Based on our empirical study, we derive a set of recommendations for establishing and maintaining successful volunteer networks in insect citizen-based monitoring programs.     

Clinical aspects of Marburg hemorrhagic fever

Marburg virus belongs to the genus Marburgvirus in the family Filoviridae and causes a severe hemorrhagic fever, known as Marburg hemorrhagic fever (MHF), in both humans and nonhuman primates. Similar to the more widely known Ebola hemorrhagic fever, MHF is characterized by systemic viral replication, immunosuppression and abnormal inflammatory responses. These pathological features of the disease contribute to a number of systemic dysfunctions including hemorrhages, edema, coagulation abnormalities and, ultimately, multiorgan failure and shock, often resulting in death. A detailed understanding of the pathological processes that lead to this devastating disease remains elusive, a fact that contributes to the lack of licensed vaccines or effective therapeutics. This article will review the clinical aspects of MHF and discuss the pathogenesis and possible options for diagnosis, treatment and prevention.     

A molecular approach to unraveling the genetics of sugarcane, a complex polyploid of the Andropogoneae tribe.

Modern sugarcane varieties are complex aneuploids and typically have chromosome numbers in the 100-125 range with about 5-10% of them contributed by wild relatives, mainly Saccharum spontaneum, and the rest by S. officinarum. This particular genomic constitution was found favorable for mapping the S. spontaneum genome, using maize as a diploid reference for comparison. We conducted an analysis of 32 individuals derived from the selfing of variety SP 701006 using four isozymes and 53 maize probes which covered the whole maize genome. A total of 348 segregating bands were generated. Highly significant cosegregations enabled us to place 94 markers into 25 cosegregation groups. Eighteen of these groups involved S. spontaneum specific markers and might therefore mark S. spontaneum chromosomes in segregation. On the basis of probes in common, the 25 cosegregation groups could be assembled into eight tentative linkage groups, of which seven describe S. spontaneum chromosomes. A large degree of synteny between sugarcane and maize could be inferred, with a much lower rate of recombination in sugarcane.