Vielfältiges Leben in Sand und Heide

Excursion in Brandenburg: Species richness in sand heathlands After many decades of an intensive military use, the former military training areas of Eastern Germany play a major role as huge, unfragmented biodiversity hotspots. While intensive agriculture causes a serious threat to many species in our cultural landscape, heathlands and dry grasslands are unique habitats on the nutrient‐poor soils in the “box of sand” of the Mark Brandenburg. But these habitats need a strong conservation management with targeted nursing measures such as removal of shrubs, grazing, soil wounding and controlled burning. However, some forest sites of the military training areas are often suitable for a wilderness development. The Heinz Sielmann Foundation pursues these nature conservation objectives and makes great nature experiences possible in the conservation areas.     

Dynamisches Epigenom als Vermittler zwischen Umwelt und Genom

The epigenome serves as an interface between the dynamic environment and the inherited static genome. It is comprised of chromatin and a covalent modification of DNA by methylation. The epigenome is sculpted during development to shape the diversity of gene expression programs in the organism’s different cell types by a highly organized process. Epigenetic aberrations have consequences similar to those of genetic polymorphisms, resulting in variations in gene function. Recent data suggest that the epigenome is dynamic and is therefore responsive to environmental signals, not only during the critical periods in development but also later in life. It is postulated here that not only chemicals but also exposure to social behavior, such as maternal care, may affect the epigenome. It is proposed that exposure to different environmental agents could lead to interindividual phenotypic diversity as well as to varying susceptibility to disease and behavioral pathologies. Interindividual differences in the epige­netic state could also affect susceptibility to xenobiotics.     

Über die Beziehung zwischen Systematik und Evolution

The relation between systematics and evolution The theoretical and methodological decoupling of pattern analysis from the causal explanation of the hierarchical order of nature by the hypothesis of descent with modification is defended. This contrasts with the philosophy of phylogenetic systematics which views acceptance of evolutionary theory as a necessary prerequisite for research in systematics.     

Klonen von Nutztieren. Tierzucht zwischen Landwirtschaft und Biomedizin

Somatic cloning in animal production The great success of animal production is primarily associated with the application of various reproductive biotechnologies, such as artificial insemination, embryo transfer, etc. Somatic cloning ist the most recent biotechnological method for which field application is emerging. Until today, somatic cloning has been successful in >15 different species. Current success rates, i.e. the production of live offspring, are still lower compared with conventionl production methods. However, worldwide research has led to significant improvements of the cloning technology which do allow field application for certain targets in cattle and pigs.     

Thallium-transfer von Böden in pflanzen. korrelation zwischen chemischer form und Pflanzenaufnahme

Zusammenfassung Auf zwei unterschiedlich stark durch Thallium belasteten B?den des Neckarschuttkegels im Raum Heidelberg (BRD) wurde durch Anbau von Winterraps (Brassica napus L. var. napus) eine signifikante Abnahme der Thalliumgehalte beobachtet. Die Pflanzen reicherten das Metall auf dem belasteten Boden in h?herem Ma?e an als auf dem unbelasteten. Sequenzielle Extraktionen zeigten, da? gro?e Anteile des Thalliums in dem durch ein Zementwerk belastenten Boden leicht adsorptiv gebunden waren. Ebenso wie im Totalaufschlu? der B?den konnte in jeder Extraktionsphase der Thalliumverlust durch Rapsanbau ermittelt werden. Ein Vergleich der Extrahierbarkeit mit der tats?chlichen Entnahme erweist das Extraktionsverfahren als geeignet, die Pflanzenverfügbarkeit des untersuchten Schwermetalls in verschiedenen B?den abzusch?tzen. Eine quantitative Voraussage der von Pflanzen zu erwartenden Thalliumaufnahme ist damit jedoch nicht m?glich.      

Die stoffwechselphysiologischen Beziehungen zwischen Paramecium bursaria Ehrbg. und Chlorella spec. in der Paramecium bursaria-Symbiose

Zusammenfassung Infektionsexperimente algenfreier Paramecium bursaria mit aus diesen isolierten und unter Stickstoffmangel-Bedingungen vorkultivierten Algen deuten darauf hin, daß die Versorgung der endosymbiontischen Algen mit stickstoffhaltigen Verbindungen durch ihren Wirt in einem zu gutem Wachstum und Vermehrung der Alge ausreichendem Maße möglich ist. Die Bedeutung dieser stoffwechselphysiologischen Beziehung für die Symbiosepartner wird diskutiert.Die Vergiftung der Photosynthese der endosymbiontischen Chlorella durch 3-(3,4-Dichlorphenyl)-1,1-dimethylharnstoff (DCMU) führt in grünen Paramecium bursaria durch Beeinflussung des Kohlenstoff-Stoffwechsels zu einer Entkoppelung des symbiontischen steady state-Systems und damit zur Auflösung der Symbiose. Eine ausreichende heterotrophe Ernährung der Alge durch das Paramecium ist in der Symbiose offenbar nicht möglich.Die Anwendung von 3-(3,4-Dichlorphenyl)-1,1-dimethylharnstoff (DCMU) kann als neue Methode zur Züchtung algenfreier Paramecium bursaria dienen.

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The metabolic interactions between Paramecium bursaria Ehrbg. and Chlorella spec. in the Paramecium bursaria-symbiosisI. The nitrogen and the carbon metabolism

Symbiotic Chlorellae have been isolated from Paramecium bursaria Ehrbg. and cultivated under conditions of nitrogen deficiency. Reinfection of Chlorella-free Paramecium bursaria with these nitrogen-deficient algae resulted in a complete regeneration and multiplication of the algae within the host cells. The endosymbiotic algal cells of the Paramecium bursaria-symbiosis can be supplied by their host with nitrogen.The inhibition of photosynthesis by 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) leads in green Paramecium bursaria to a breakdown of the symbiotic steady state-system resulting in a loss of algal cells. Obviously the endosymbiotic algae cannot be fed heterotrophically by their host to such an extent that a stable symbiosis is maintained.The application of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) can be used as a new method for culturing Chlorella-free Paramecium bursaria.

     

Der Zusammenhang zwischen Lokomotionsweise,Begattungsstellung und Penislänge bei Säugetieren1

Penis length, copulation and locomotion: Their relationship to each other in Mammals A relationship between the mode of locomotion, copulatory position and length of the male copulative organ has been found in all groups of Mammalia. In this paper particular emphasis is given to the orders of the Testiconda, while the Testiphaena receive only brief account (for explanation of terms see Frey 1991 a). Results from my previous antomical study are utilized that are essential for assessing the respective modes of locomotion (Frey 1991b). Information on penis length and copulatory position are taken from the literature and evaluated. Small and middle-sized Testiphaena, which represent the majority of mammals, are capable of a dynamic sagittal bending in the trunk, which is evidenced both in the galloping mode of locomotion and in the usual mammalian copulatory position (mounting). A sagittal bending of the trunk enables the male to bring his genital region into close proximity of the female's genital opening. In this case, a short penis is sufficient to ensure sperm transfer. The construction of the trunk in the Testiconda (excepting the Hyracoidea) entirely or nearly entirely prevents the sagittal bending. This is largely due to rigidity of the lumbar region or insufficient (dynamic) muscular control. The immobilization and/or the functional weakness of the lumbar region are derived from different anatomical conditions. 1. Shortening of the lumbar region, e.g., Tachyglossidae, Elephantidae, Sirenia; 2. Tightening of the lumbar region by tendons and muscles, e. g., Macroscelididae, Cetacea; 3. Xenarthry of the lumbar vertebrae and a double connection of the pelvis on the vertebral column, e. e., Bradypodidae, Myrmeco-phagidae; 4. The lumbar region may be flexible but the hypaxial muscles too short and weak, e. g., Tenrecinae, Soricidae, Erinaceidae. Lumbar rigidity or insufficient muscular control in the lumbar region, resulting from any of these conditions, makes copulation difficult by restricting close approximation of the male and female genitals. Most Testiconda compensate for this by having a long penis. The same also applies for large-sized Testiphaena. Although these animals have retained the ability to gallop, the flexibility of their trunk is restricted and mostly localized in a single joint due to the great body mass and the constructive constraints necessary for increased stability. A long penis is not the only way to compensate for the absence of sagittal flexion. A phylogenetic change in the copulatory posture also solves the problem as seen in the Myr-mecophagidae and Bradypodidae (both Testiconda) which are equipped with a secondarily short-enedpenis. The permanently aquatic testicondid mammals (Sirenia and Cetacea) cannot copulate in the usual mammalian mount position. This is largely due to the phylogenetic reduction and reconstruction of the extremities as well as the secondary evolution of a powerful tail. Sagittal movements of the heavily musculated tail act upon the more or less rigid trunk to provide for a “rear drive” locomotion. Both a change in the copulatory position and a long penis were necessary for these aquatic mammals. The only Testiconda in which a marked dynamic sagittal flexibility of the trunk is developed -the Hyracoidea - are characterized by a short penis. On the whole, the relationship between the mode of locomotion, copulatory position and penis length within the mammalia is confirmed. A rigid lumbar region as opposed to a sagittally flexible, presumably represents the primitive condition among mammals. All Testiconda have     

Der Zusammenhang zwischen Begattungsstellung, Lokomotionsweise und Kopulationsorgan bei Vertebrata, mit Ausnahme der Mammalia. Eine vergleichende Betrachtung

Copulatory organ, mating posture and locomotion: their interrelationship in non-mammalian vertebrates. This paper demonstrates, for the vertebrate groups discussed, a relationship between mating posture, the length of the copulatory organ, and the respective modes of locomotion. The modes of locomotion in the majority of non-mammalian vertebrate groups presuppose a massive, heavily muscularized, and relatively long tail, which may either reinforce lateral flexions of the trunk or (in animals with rigid trunk) act as the only means of propulsion (e.g. in Chondrichthyes, Teleostei, Lepidosauria, and Crocodylia). Such a massive tail with gradual transition to the trunk necessitates a lateral mating position (regardless of whether the copulatory organ is paired or unpaired). Animals with a flexible trunk will, therefore, generate strongly pronounced laterotruncal flexions (‘dynamic lateral bending’). A long copulatory organ is not necessary (e.g. the short hemipenes of Lepidosauria). Animals with a rigid trunk, on the other hand, will not be capable of copulating unless by means of a relatively long penis or a modified mating posture (e.g. Crocodylia). In the course of phylogeny, whenever a change in the mode of locomotion allows a reduction in tail length, this will lead to a corresponding change in mating posture, with mating then being possible from a posterior position (e.g. Chelonia, Aves, as well as Ascaphus among the Anura). The locomotion of the latter taxa is characterized by a completely or almost completely rigid trunk. Thus, contact between male and female cloaca cannot be assisted by bending movements in the trunk. To compensate for truncal rigidity, there is a trend towards linear extension of the penis, or other male copulatory organs (such as mixopterygia or gonopodia), e.g. in the pelagic Selachians, in Chelonia, and in the flightless ratites. For those birds lacking a penis, the only methods of overcoming truncal rigidity are stationary locomotion (fluttering without forward movement), having a mobile, swivelling cloacal region (uropygium), and simultaneous evagination of the proctodeum of both the male and female. Penguins, being unable to perform stationary fluttering, resort to a somewhat modified mating posture.