Isolation of a cDNA encoding a novel human FK506-binding protein homolog containing leucine zipper and tetratricopeptide repeat motifs

Reduced-stringency PCR was used to isolate a cDNA encoding a novel human FK506-binding protein (FKBP) homolog. The encoded 38-kDa protein (FKBPr38) contains at its N-terminus a domain that is 33% identical to FKBP12. FKBPr38 is a member of a subclass of immunophilins, whose other members include FKBP52 and CyP40 (cyclophilin 40), that contain a three-unit tetratricopeptide repeat (TPR). In addition, FKBPr38 contains a consensus leucine-zipper repeat. The presence of the TPR domain and leucine zipper suggest that FKBPr38 may form homomultimers or interact with other, as yet unidentified, proteins.     

Use of DNA fingerprinting for human population genetic studies

DNA fingerprinting techniques have been used in population genetic studies on many different kinds of organisms. Here, we present new applications for multilocus DNA fingerprint probes in population studies and demonstrate the applicability of DNA fingerprinting to human population genetics, using M13 phage DNA as a probe. The new approach, which is based on a factor method of numerical coding of non-quantitative data (factor correspondence analysis-FCA), shows good agreement between population position, as indicated by the three principal factors, and ethnogenetic proximity.     

Reduced mate availability leads to evolution of self‐fertilization and purging of inbreeding depression in a hermaphrodite

Basic models of mating‐system evolution predict that hermaphroditic organisms should mostly either cross‐fertilize, or self‐fertilize, due to self‐reinforcing coevolution of inbreeding depression and outcrossing rates. However transitions between mating systems occur. A plausible scenario for such transitions assumes that a decrease in pollinator or mate availability temporarily constrains outcrossing populations to self‐fertilize as a reproductive assurance strategy. This should trigger a purge of inbreeding depression, which in turn encourages individuals to self‐fertilize more often and finally to reduce male allocation. We tested the predictions of this scenario using the freshwater snail Physa acuta, a self‐compatible hermaphrodite that preferentially outcrosses and exhibits high inbreeding depression in natural populations. From an outbred population, we built two types of experimental evolution lines, controls (outcrossing every generation) and constrained lines (in which mates were often unavailable, forcing individuals to self‐fertilize). After ca. 20 generations, individuals from constrained lines initiated self‐fertilization earlier in life and had purged most of their inbreeding depression compared to controls. However, their male allocation remained unchanged. Our study suggests that the mating system can rapidly evolve as a response to reduced mating opportunities, supporting the reproductive assurance scenario of transitions from outcrossing to selfing.     

Ultrastructural and Phylogenetic Description of Kudoa orbicularis n. sp. (Myxosporea: Multivalvulida): A Parasite Infecting the Muscle of the Fish Chaetobranchopsis orbicularis (Teleostei: Cichlidae) in the Amazon Region

A new myxosporean species is described from the muscle of the Amazonian freshwater fish Chaetobranchopsis orbicularis (Teleostei, Cichlidae), with basis on morphometric, ultrastructural and molecular data. Numerous myxospores were observed within pseudocysts located on the hosts' dorsal and ventral muscles, near the neural spines and neural canal (spinal cord). Mature myxospores quadrangular with rounded ends in apical view, measuring 4.3 (3.6–5.0) μm in length and 5.1 (4.2–5.8) μm in width. The myxospores wall is formed by four symmetric valves. Within, four pyriform polar capsules, 2.1 (1.7–2.6) μm long and 1.3 (0.9–1.7) μm wide, located two by two in opposite sides of the myxospores longitudinal axis, each containing a polar filament forming 2–3 coils. Molecular analysis of the SSU rRNA gene by maximum likelihood, neighbor‐joining and maximum parsimony confirms the parasite as a new member of the genus Kudoa, herein named Kudoa orbicularis n. sp., the second species of its genus reported from the South American freshwater fauna, and the fourth species worldwide known to occur in the freshwater environment. Furthermore, its sequence of the SSU rRNA gene constitutes the first entry of a freshwater Kudoa species in GenBank.     

Structural studies of monoclonal human cryoprecipitable immunoglobulins

The light chain type, immunoglobulin class and when possible, heavy chain subclass of eleven monoclonal human cryoglobulins were correlated with the variable region subgroup of their light chains. The variable region subgroups were assigned by determining the primary amino acid sequence for the first 15 amino-terminal residues of these light chains. $\text{5}\text{5}$ IgM cryoglobulins which react with human IgG had light chains of the variable region-III kappa chain subgroup (vK-III). $\text{4}\text{4}$ IgG and $\text{2}\text{2}$ IgM cryoglobulins with undefined antibody specificity had both lambda and kappa light chains none of which were vK-III. The data support the concept that there is marked restriction of the IgM anti-IgG antibody response to the IgG auto-antigen.     

Phosphatase-Aktivität in Hydathoden 1

Zusammenfassung Das Gewebe, welches in den Hydathoden zwischen Leitbündelende und Wasserspalten eingeschaltet ist, wird als Hydathodengewebe definiert (topographischer Begriff). Unabhängig davon, ob dieses Gewebe aus Mesophyllzellen besteht (Triticum), ob es ein scheidenloses Epithem vorstellt (Tropaeolum) oder ob es mit einer Scheide versehen in ein Zuleitungs- und ein Ausscheidungsgewebe differenziert ist (Alchemilla, Saxifraga), weist es beim histochemischen Test eine auffallende Aktivität der sauren Phosphatase auf.Da der Phosphatasenachweis in den dem aktiven Gewebe benachbarten Zellen der Epithemscheide, des Mesophylls und der Epidermis bei unseren Objekten negativ ausfällt, muß den Zellen des Hydathodengewebes ein besonderer Stoffwechsel zukommen. Dieser ist bei dem ins Hydathodengewebe vordringenden Xylemparenchym ausgeprägter als im Ausscheidungsgewebe unmittelbar unter den Wasserspalten (Alchemilla, Abb. 4).Es besteht eine auffällige Analogie mit den Nektarien, wo sich das Nektargewebe ebenfalls mit der Phosphatasereaktion gegenüber dem inaktiven Grundgewebe oder dem Mesophyll abgrenzen läßt, und wo das Ausscheidungsgewebe gleichfalls weniger aktiv als das Zuführungsgewebe erscheint. Ferner weisen die Xylemparenchymzellen im Bereiche der Hydathoden eine ähnlich starke Reaktion auf wie die Geleitzellen der Siebröhren. Der gefundene Parallelismus läßt es fraglich erscheinen, ob die Phosphatasereaktion im Phloem und in den Nektarien spezifisch für die Zuckerwanderung sei. Denn man stellt fest, daß die Hydathodengewebe, unabhängig davon, ob sie als Filtrations- oder als Ausscheidungsgewebe ausgebildet sind, eine ähnlich rege Aktivität der sauren Phosphatase entwickeln wie die zuckerverarbeitenden Gewebe. Die nachgewiesene histochemische Analogie der Hydathodengewebe mit dem Nektargewebe muß daher auf einer anderen stoffwechselchemischen Übereinstimmung beruhen.Herrn Professor Dr. K. Höfler zum 70. Geburtstage gewidmet.     

Oxime reactivation of erythrocyte cholinesterase inhibited by ethyl p-nitrophenyl ethylphosphonate

1. Reactivation of erythrocyte cholinesterase inhibited by ethyl p-nitrophenyl ethylphosphonate (armine) was studied with NN'-dimethylenebis-(4-hydroxy-iminomethylpyridinium bromide) (C(2)-oxime), NN'-trimethylenebis-(4-hydroxy-iminomethylpyridinium bromide) (C(3)-oxime), NN'-tetramethylene-(4-hydroxy-iminomethylpyridinium bromide) (C(4)-oxime) and NN'-pentamethylenebis-(4-hydroxyiminomethylpyridinium bromide) (C(5)-oxime) as reactivators. The kinetics of reactivation were consistent with a reaction of the type: [Formula: see text] and bimolecular rate constants for reactivation were calculated from the corresponding differential equations. 2. Of the four oximes studied C(2)-oxime was least effective and the other three oximes were about equally effective reactivators. 3. Reactivation of armine-inhibited cholinesterase by C(3)-oxime was also studied in the presence of substrate. This reaction was first-order with respect to inhibited enzyme, and slower than in the absence of substrate.     

Histochemical demonstration of carbonic anhydrase activity in the alimentary canal

Summary Carbonic anhydrase (CAH) activity was histochemically demonstrated in various parts of the alimentary canal of rat and in the stomach of man using the method of Waldeyer and Häusler (1959). The most intense histochemical reaction was observed in the parietal cells of the rat stomach, and reactions of decreasing intensity in the epithelial cells of the colon, appendix, jejunoileum, duodenum and oesophagus in the order mentioned. An intense reaction was also observed in the parietal cells of the stomach of man and a weak activity in the pyloric glands. After electrophoresis on cellulose acetate film the CAH activity in human and rat stomach mucosa showed one band with the same migration rate as the fastest moving band of the erythrocyte CAH.