Der Neodarwinismus als axiomatisierbares deduktives System und das Problem der Anpassung und Selektion

In the last decade numerous evolutionary models have been proposed and intensively discussed. Surprisingly, the logical analysis of these different hypotheses is not of great importance in this debate. As a matter of fact, Neodarwinism is a consistent deductive system which is based on few but wellconfirmed axioms. Hence, very often, precise statements and definitions of standpoint can be made. This is exemplified by some repeatedly discussed models concerning the problems of Darwinian »adaptation« and »natural selection« 1. Following the logic of the Neodarwinian theory, extinction can only be the result of overspecialization if some very unusual assumptions are made. 2. The hypothesis of »punctuated equilibrium« GOULD 1982), the »effect hypothesis« (VRBA 1983) and the stochastic evolutionary model SCHOPF 1979) include elements which are logically inconsistent with the »modern synthesis«; they could be »true« only if at least one of the neodarwinian axioms (so far not disproved) is negated.     

FMRFamide-like immunoreactivity in the brain and pituitary of the teleost. Eigenmannia lineata (Gymnotiformes)

The distribution of cells immunoreactive for the molluscan tetrapeptide FMRFamide in the brain and the pituitary of Eigenmannia was investigated immunohistochemically by the use of the peroxidase-antiperoxidase (PAP) technique and unlabelled antibodies. FMRFi neurons were located in the ganglion of the nervus terminalis at the rostroventral side of the bulbus olfactorius. FMRFi perikarya were also found in a dorsomedial diencephalic nucleus, in the nucleus ventromedialis, in some liquor-contacting neurons of the nucleus lateralis tuberis and of the nucleus recessus lateralis and posterior. The perikarya of the midbrain pre-pacemaker nucleus were only weakly immunoreactive for FMRFamide while large FMRFi neurons (T-cells) occurred in lamina VI of the torus semicircularis, in the brain stem, in dorsal and medial layers of the lobus lineae lateralis posterior (LLLp) and in the medullary electric organ pacemaker nucleus (pm). FMRFi fibers and nerve endings were found in the bulbus olfactorius, in medial areas of the telencephalon, and rather densely in the rostral diencephalon. Ventrocaudally to most of the hypothalamic nuclei the occurrence of immunoreactive fibres increased; many coursed to the pituitary through the pituitary stalk. FMRFi fibres also appeared in the deep layers of the tectum opticum, in the torus semicircularis, in the medial and lateral medulla and below the pacemaker nucleus. Wherever FMRFamide-immunoreactivity occurred fibres and nerve endings could be found in close contact with blood vessels.     

Analysis of biochemical genetic data on Jewish populations: II. Results and interpretations of heterogeneity indices and distance measures with respect to standards.

A nonparametric statistical methodology is used for the analysis of biochemical frequency data observed on a series of nine Jewish and six non-Jewish populations. Two categories of statistics are used: heterogeneity indices and various distance measures with respect to a standard. The latter are more discriminating in exploiting historical, geographical and culturally relevant information. A number of partial orderings and distance relationships among the populations are determined. Our concern in this study is to analyze similarities and differences among the Jewish populations, in terms of the gene frequency distributions for a number of genetic markers. Typical questions discussed are as follows: These Jewish populations differ in certain morphological and anthropometric traits. Are there corresponding differences in biochemical genetic constitution? How can we assess the extent of heterogeneity between and within groupings? Which class of markers (blood typings or protein loci) discriminates better among the separate populations? The results are quite surprising. For example, we found the Ashkenazi, Sephardi and Iraqi Jewish populations to be consistently close in genetic constitution and distant from all the other populations, namely the Yemenite and Cochin Jews, the Arabs, and the non-Jewish German and Russian populations. We found the Polish Jewish community the most heterogeneous among all Jewish populations. The blood loci discriminate better than the protein loci. A number of possible interpretations and hypotheses for these and other results are offered. The method devised for this analysis should prove useful in studying similarities and differences for other groups of populations for which substantial biochemical polymorphic data are available.     

Structure of the species--energy relationship

The relationship between energy availability and species richness (the species-energy relationship) is one of the best documented macroecological phenomena. However, the structure of species distribution along the gradient, the proximate driver of the relationship, is poorly known. Here, using data on the distribution of birds in southern Africa, for which species richness increases linearly with energy availability, we provide an explicit determination of this structure. We show that most species exhibit increasing occupancy towards more productive regions (occurring in more grid cells within a productivity class). However, average reporting rates per species within occupied grid cells, a correlate of local density, do not show a similar increase. The mean range of used energy levels and the mean geographical range size of species in southern Africa decreases along the energy gradient, as most species are present at high productivity levels but only some can extend their ranges towards lower levels. Species turnover among grid cells consequently decreases towards high energy levels. In summary, these patterns support the hypothesis that higher productivity leads to more species by increasing the probability of occurrence of resources that enable the persistence of viable populations, without necessarily affecting local population densities.     

Effect of native phosphocaseinate on the in vitro preservation of fresh semen

The fertilization capacity of goat sperm stored in milk extenders is approximately 12-24h. Long-term storage of goat sperm (up to 3 days) is desirable as it would confer greater flexibility to breeding farms. The aim of this study was to evaluate in vitro motility parameters of buck spermatozoa for up to 7 days of storage using skim milk or chemically defined extender supplemented with native phosphocaseinate (NPPC). Four experiments were conducted to determine optimum temperature (4 or 15 degrees C) and storage conditions (aerobic versus anaerobic), the effect of seminal plasma on sperm survival, the optimal concentration of NPPC and the effect of beta lactoglobulin (BL). Both skim milk and NPPC were found to be more efficient for preserving goat sperm at 4 degrees C than at 15 degrees C (P<0.01). Furthermore, when sperm was stored at 4 degrees C, no detrimental effects of seminal plasma were observed. Our results showed that motility parameters can be maintained with success until Day 4. However, NPPC-based extenders extend the in vitro survival to 7 days of storage. The optimal concentration of NPPC for the preservation of sperm cells for 4 days of storage was 81g/l and for 7 days of storage was 81 and 54g/l. No effect of the supplementation of the NPPC extender with BL was found.     

Subtypes of the plasmid-encoded serine protease EspP in Shiga toxin-producing Escherichia coli: distribution, secretion, and proteolytic activity

We investigated the prevalence, distribution, and structure of espP in Shiga toxin-producing Escherichia coli (STEC) and assessed the secretion and proteolytic activity of the encoded autotransporter protein EspP (extracellular serine protease, plasmid encoded). espP was identified in 56 of 107 different STEC serotypes. Sequencing of a 3,747-bp region of the 3,900-bp espP gene distinguished four alleles (espPalpha, espPbeta, espPgamma, and espPdelta), with 99.9%, 99.2%, 95.3%, and 95.1% homology, respectively, to espP of E. coli O157:H7 strain EDL933. The espPbeta, espPgamma, and espPdelta genes contained unique insertions and/or clustered point mutations that enabled allele-specific PCRs; these demonstrated the presence of espPalpha, espPbeta, espPgamma, and espPdelta in STEC isolates belonging to 17, 16, 15, and 8 serotypes, respectively. Among four subtypes of EspP encoded by these alleles, EspPalpha (produced by enterohemorrhagic E. coli [EHEC] O157:H7 and the major non-O157 EHEC serotypes) and EspPgamma cleaved pepsin A, human coagulation factor V, and an oligopeptide alanine-alanine-proline-leucine-para-nitroaniline, whereas EspPbeta and EspPdelta either were not secreted or were proteolytically inactive. The lack of proteolysis correlated with point mutations near the active serine protease site. We conclude that espP is widely distributed among STEC strains and displays genetic heterogeneity, which can be used for subtyping and which affects EspP activity. The presence of proteolytically active EspP in EHEC serogroups O157, O26, O111, and O145, which are bona fide human pathogens, suggests that EspP might play a role as an EHEC virulence factor.     

Combinatorial expression of alpha- and gamma-protocadherins alters their presenilin-dependent processing

Alpha- and gamma-protocadherins (Pcdhs) are type I transmembrane receptors expressed predominantly in the central nervous system and located in part in synapses. They are transcribed from complex genomic loci, giving rise in the mouse to 14 alpha-Pcdh and 22 gamma-Pcdh isoforms consisting of variable domains, each encompassing the extracellular region, the transmembrane region, and part of the intracellular region harboring the alpha- or gamma-Pcdh-specific invariant cytoplasmic domain. Presenilin-dependent intramembrane proteolysis (PS-IP) of gamma-Pcdhs and the formation of alpha/gamma-Pcdh heteromers led us to investigate the effects of homo- and heteromer formation on gamma- and putative alpha-Pcdh membrane processing and signaling. We find that upon surface delivery, alpha-Pcdhs, like gamma-Pcdhs, are subject to matrix metallo-protease cleavage followed by PS-IP in neurons. We further demonstrate that the combinatorial expression of alpha- and gamma-Pcdhs modulates the extent of their PS-IP, indicating the formation of alpha/gamma-Pcdh heteromers with an altered susceptibility to processing. Cell-specific expression of alpha/gamma-Pcdh isoforms could thus determine cell and synapse adhesive properties as well as intracellular and nuclear signaling by their soluble cytoplasmic cleavage products, alpha C-terminal fragment 2 (alpha-CTF-2) and gamma-CTF-2.     

Alternative profiling platform based on MELDI and its applicability in clinical proteomics

The presence of numerous proteomics data and their results in literature reveal the importance and influence of proteins and peptides on human cell cycle. For instance, the proteomic profiling of biological samples, such as serum, plasma or cells, and their organelles, carried out by surface-enhanced laser desorption/ionization mass spectrometry, has led to the discovery of numerous key proteins involved in many biological disease processes. However, questions still remain regarding the reproducibility, bioinformatic artifacts and cross-validations of such experimental set-ups. The authors have developed a material-based approach, termed material-enhanced laser desorption/ionization mass spectrometry (MELDI-MS), to facilitate and improve the robustness of large-scale proteomic experiments. MELDI-MS includes a fully automated protein-profiling platform, from sample preparation and analysis to data processing involving state-of-the-art methods, which can be further improved. Multiplexed protein pattern analysis, based on material morphology, physical characteristics and chemical functionalities provides a multitude of protein patterns and allows prostate cancer samples to be distinguished from non-prostate cancer samples. Furthermore, MELDI-MS enables not only the analysis of protein signatures, but also the identification of potential discriminating peaks via capillary liquid chromatography mass spectrometry. The optimized MELDI approach offers a complete proteomics platform with improved sensitivity, selectivity and short sample preparation times.