Genetische Und Zytologische Untersuchungen an Verschiedenen Sippen Von Oenothera Suaveolens

Ohne ZusammenfassungMit 7 Textabbildungen.In ausführlicherer Form und mit zahlreichen Abbildungen als Dissertation bei der Naturwissenschaftlichen Fakultät der Universität München eingereicht.     

Untersuchungen über den Energiehaushalt der Hefezelle und die Ökonomie einiger Energiestoffwechseltypen anderer Mikroorganismen

Ohne ZusammenfassungAuszug aus einer Dissertation der mathem.-naturw. Fakultät der Universität Göttingen 1951.     

Presence of hybridizing DNA sequences homologous to bovine acidic and basicβ-crystallins in all classes of vertebrates

Summary The eye lens-crystallins in cow and chicken are encoded by a family of at least six genes. In order to assess the distribution of the corresponding genes among other vertebrates we hybridized -crystallin sequences (A2, A3/A1, A4, B1, B2, B3), isolated from a bovine lens cDNA library, to Southern blots on whichEcoR1-digested chromosomal DNA was blotted from different vertebrate species. These included human, chimpanzee, calf, rat, pigeon, duck, monitor lizard, toad, trout, and lamprey. Positive hybridization signals were found in the representatives of virtually all classes of vertebrates. The basic B-crystallins gave hybridization signals in more species than the acidic A ones. In monitor lizard and toad the weakest hybridization signals for basic crystallin probes were found. For acidic crystallin probes the distribution pattern was more simple; among cold-blooded vertebrates a signal for A2 was found in trout and lamprey, for A4 in trout, and for A3/A1 only in toad. The results demonstrate that the duplications leading to the -crystallin gene family occurred before or during the earliest stages of vertebrate evolution.     

Sexual selection and maintenance of sex: evidence from comparisons of rates of genomic accumulation of mutations and divergence of sex-related genes in sexual and hermaphroditic species of Caenorhabditis

Several hypotheses have been proposed to explain the persistenceof dioecy despite the reproductive advantages conferred to hermaphrodites,including greater efficiency at purging deleterious mutationsin the former. Dioecy can benefit from both mutation purgingand accelerated evolution by bringing together beneficial mutationsin the same individual via recombination and shuffling of genotypes.In addition, mathematical treatment has shown that sexual selectionis also capable of mitigating the cost of maintaining separatesexes by increasing the overall fitness of sexual populations,and genomic comparisons have shown that sexual selection canlead to accelerated evolution. Here, we examine the advantagesof dioecy versus hermaphroditism by comparing the rate of evolutionin sex-related genes and the rate of accumulation of deleteriousmutations using a large number of orthologs (11,493) in thedioecious Caenorhabditis remanei and the hermaphroditic Caenorhabditisbriggsae. We have used this data set to estimate the deleteriousmutation rate per generation, U, in both species and find thatalthough it is significantly higher in hermaphrodites, bothspecies are at least 2 orders of magnitude lower than the valuerequired to explain the persistence of sex by efficiency atpurging deleterious mutations alone. We also find that genesexpressed in sperm are evolving rapidly in both species; however,they show a greater increase in their rate of evolution relativeto genes expressed in other tissues in C. remanei, suggestingstronger sexual selection pressure acting on these genes indioecious species. Interestingly, the persistence of a signalof rapid evolution of sperm genes in C. briggsae suggests arecent evolutionary origin of hermaphrodism in this lineage.Our results provide empirical evidence of increased sexual selectionpressure in dioecious animals, supporting the possibility thatsexual selection may play an important role in the maintenanceof sexual reproduction.     

Effect of Footwear Modifications on Oscillations at the Achilles Tendon during Running on a Treadmill and Over Ground: A Cross-Sectional Study

Background

Achilles tendon injuries are known to commonly occur in runners. During running repeated impacts are transferred in axial direction along the lower leg, therefore possibly affecting the oscillation behavior of the Achilles tendon. The purpose of the present study was to explore the effects of different footwear modifications and different ground conditions (over ground versus treadmill) on oscillations at the Achilles tendon.

Methods

Oscillations were measured in 20 male runners using two tri-axial accelerometers. Participants ran in three different shoe types on a treadmill and over ground. Data analysis was limited to stance phase and performed in time and frequency space. Statistical comparison was conducted between oscillations in vertical and horizontal direction, between running shoes and between ground conditions (treadmill versus over ground running).

Results

Differences in the oscillation behavior could be detected between measurement directions with peak accelerations in the vertical being lower than those in the horizontal direction, p < 0.01. Peak accelerations occurred earlier at the distal accelerometer than at the proximal one, p < 0.01. Average normalized power differed between running shoes (p < 0.01) with harder damping material resulting in higher power values. Little to no power attenuation was found between the two accelerometers. Oscillation behavior of the Achilles tendon is not influenced by ground condition.

Conclusion

Differences in shoe configurations may lead to variations in running technique and impact forces and therefore result in alterations of the vibration behavior at the Achilles tendon. The absence of power attenuation may have been caused by either a short distance between the two accelerometers or high stiffness of the tendon. High stiffness of the tendon will lead to complete transmission of the signal along the Achilles tendon and therefore no attenuation occurs.     

Involvement of a phospholipase C in the hemolytic activity of a clinical strain of <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis>

Background  

Pseudomonas fluorescens is a ubiquitous Gram-negative bacterium frequently encountered in hospitals as a contaminant of injectable material and surfaces. This psychrotrophic bacterium, commonly described as unable to grow at temperatures above 32°C, is now considered non pathogenic. We studied a recently identified clinical strain of P. fluorescens biovar I, MFN1032, which is considered to cause human lung infection and can grow at 37°C in laboratory conditions.     

Identification and re-addressing of a transcriptionally permissive locus in the porcine genome

Recently, we established the Sleeping Beauty transposon system for germ line competent transgenesis in the pig. Here, we extend this approach to re-target a transposon-tagged locus for a site-specific gene knock-in, and generated a syngeneic cohort of piglets carrying either the original transposon or the re-targeted event. A Cre-loxP-mediated cassette exchange of the tagging transposon with a different reporter gene was performed, followed by flow cytometric sorting and somatic cell nuclear transfer of recombined cells. In parallel, the original cells were employed in somatic cell nuclear transfer to generate clone siblings, thereby resulting in a clone cohort of piglets carrying different reporter transposons at an identical chromosomal location. Importantly, this strategy supersedes the need for an antibiotic selection marker. This approach expands the arsenal of genome engineering technologies in domestic animals, and will facilitate the development of large animal models for human diseases. Potentially, the syngeneic cohort of pigs will be instrumental for vital tracking of transplanted cells in pre-clinical assessments of novel cell therapies.