Pepsinogen-like immunoreactivity among vertebrates: occurrence of common antigenicity to an anti-chicken pepsinogen antiserum in stomach gland cells of vertebrates

Stomachs of 14 species selected from five classes of vertebrate were surveyed concerning the reactivity to an anti-adult chicken pepsinogen antiserum (anti-ACPg) with indirect immunofluorescence method. Gland cells of all these stomachs showed reactivity to the antiserum. Crude extract of stomachs from five representatives of mammals, birds, amphibians and fish showed peptic activity (at pH 2.2) of which 70-90% were pepstatin-sensitive. Zymogram and immunoblotting of crude extract revealed that the anti-ACPg-reactive proteins have peptic activity. Molecular weights of anti-ACPg-reactive proteins determined by immunoblotting coincided with the values of purified pepsinogens previously reported for these animals. These results indicate that pepsinogens have been conserved well during vertebrate evolution.     

Genome elimination in diploid and triploid Rana esculenta males: cytological evidence from DNA flow cytometry

Cytological aspects of hemiclonal (meroclonal) inheritance in diploid and triploid males of the hybridogenetic frog Rana esculenta (Rana ridibunda x Rana lessonae) have been studied by DNA flow cytometry. The fact that the R. ridibunda genome contains 16% more DNA than the R. lessonae genome provides the ability to discern cells containing genomes of any species from the water-frog complex under study. Data are presented showing that elimination of the R. ridibunda genome occurs in hybridogenetic males from certain populations. In triploid males, the cytogenetic mechanism of hemiclonal inheritance is simpler than in diploids: after the elimination of a genome (always the genome in the minority in the triploid set; "homogenizing elimination"), no compensatory duplication of the remaining genetic material is necessary, as it is in diploids. The process of elimination can be visualized in triploid males by using DNA flow cytometry to identify cells in the special phase of the spermatogonial cell cycle that we termed the E phase.     

Metabolic oxygen conformity among lower vertebrates: The toadfish revisited

Summary The relationship between the ambient oxygen tension of the medium and the standard rate of oxygen consumption of toadfish (Opsanus tau) was reinvestigated. The toadfish, previously reported to be a metabolic oxygen conformer, actually is a metabolic oxygen regulator in a manner similar to most other fishes, with a critical oxygen tension (P _c) of 29.3±3.5 mm Hg at 22 °C. This contradiction of a classical example of O₂ conformity in a lower vertebrate, when considered with other conflicting evidence for O₂ conformity among lower vertebrates, suggests that the concept that there are lower vertebrates that routinely exhibit metabolic O₂ conformity may be questionable, especially for forms with no obvious limitation of O₂ transport mechanisms.     

Synaptonemal complex protein SYCP3: Conserved polymerization properties among vertebrates

Synaptonemal complexes (SCs) are meiosis-specific, nuclear structures that are critically involved in synapsis, recombination and segregation of homologous chromosomes. Although the SC structure is conserved in evolution this is not the case for its protein components. To provide information on SC proteins which would be important for our understanding of the conserved SC structure and function, here we compared ortholog SYCP3 proteins of two evolutionary distant vertebrate species, namely rat and medaka fish. To this end we have investigated the polymerization properties of both proteins by immunocytochemistry, electron microscopy and cell fractionation. We found that despite of the sequence differences that have accumulated over the last 450 million years mammalian and fish SYCP3 have similar properties that allow them to co-assemble higher order structures under experimental conditions. We also provide a likely explanation as to how heterozygous mutations in the SYCP3 gene can lead to a defective meiosis.     

Genetic differentiation among sympatric cuckoo host races: males matter

Generalist parasites regularly evolve host-specific races that each specialize on one particular host species. Many host-specific races originate from geographically structured populations where local adaptations to different host species drive the differentiation of distinct races. However, in sympatric populations where several host races coexist, gene flow could potentially disrupt such host-specific adaptations. Here, we analyse genetic differentiation among three sympatrically breeding host races of the brood-parasitic common cuckoo, Cuculus canorus. In this species, host-specific adaptations are assumed to be controlled by females only, possibly via the female-specific W-chromosome, thereby avoiding that gene flow via males disrupts local adaptations. Although males were more likely to have offspring in two different host species (43% versus 7%), they did not have significantly more descendants being raised outside their putative foster species than females (9% versus 2%). We found significant genetic differentiation for both biparentally inherited microsatellite DNA markers and maternally inherited mitochondrial DNA markers. To our knowledge, this is the first study that finds significant genetic differentiation in biparentally inherited markers among cuckoo host-specific races. Our results imply that males also may contribute to the evolution and maintenance of the different races, and hence that the genes responsible for egg phenotype may be found on autosomal chromosomes rather than the female-specific W-chromosome as previously assumed.     

A mysterious pacemaker suture: an uncommon foreign body reaction

Surgical suture material is usually inert and nontoxic and causes minimal inflammation of tissue. However, foreign body reactions to various suture types can lead to granuloma, abscess, or even sinus formation. We report an elderly female who was incidentally detected to have a mass protruding from the incision site which was confirmed histopathologically a chronic granulomatous reaction to non absorbable suture. The foreign body granulomatous reaction to suture material in the setting of pacemaker implantation has not been described in the literature. We also discuss the existing literature on this underrecognised entity.     

Sclerotic fibroma-like dermatofibroma: an uncommon distinctive variant of dermatofibroma

Dermatofibroma (DF) is a common benign cutaneous tumor with many variants based on alterations in the morphology and composition of its diverse elements. One very infrequent type is sclerotic fibroma-like DF (SF-DF). We report 7 new cases of SF-DF. In addition, their main clinicopathological and immunohistochemical features were compared with 14 unselected common DFs and with 3 sclerotic fibromas (SFs). Microscopically, the 7 cases of SF-DFs showed an unencapsulated, well-circumscribed, hypocellular central nodule with thick collagen bundles arranged in a storiform pattern with prominent clefts. The overlying epidermis was attenuated. The periphery of this nodule was more cellular with histopathologic features of common DF. The 7 SF-DFs patients were 4 women and 3 men with a mean (+/-SD) age of 44.8 (+/-15.5) years. These 7 patients were younger than those suffering from SFs [71.0 (+/-17.3) years; (p=0.04)] and older than those presenting common DFs [30.5 (+/-12.3) years; (p=0.03)]. Immunohistochemically, spindle cells in all 7 SF-DFs were negative for CD34 and CD99. On the contrary, the 3 cases of SF were positive for CD34 and CD99. All of the common DFs were negative for CD34 and only 4 (28.6%) of them were positive for CD99. In conclusion, SF-DF is an uncommon variant of DF with similar clinicopathological and immunohistochemical features. SF-DF shares certain histopathologic features with SF but they are immunophenotypically different. Therefore, both entities should be differentiated.     

Retina of vertebrates: an internal cell reserve for regeneration

The recent data were summarized concerning the presence in the retina of fish, amphibians and birds of additional sources of growth and regeneration, alternative to the already known sources, such as growth zone of eye, pigment epithelium, and cells--precursors of rods, and which are localized in the inner nuclear layer of retina. These sources are represented by as yet not finally identified oval small cells and cells of Muller glia. Both types of cells are capable of proliferating and producing precursors for various differentiated cells, including photoreceptors or their additional precursors. The current immunochemistry data are provided, which were obtained using markers of proliferation, proneural phenotype, and specific cell differentiation in the growing retina and in the retina after various damages. The regulatory mechanisms and methods of the stimulation of proliferation of the cells, which are sources of increase in the number and restoration of photoreceptors, interneurons, and glial cells of vertebrate retina, are discussed.     

Haematological characterization of loach Misgurnus anguillicaudatus: comparison among diploid, triploid and tetraploid specimens

The purpose of this study was to determine whether diploid, triploid and tetraploid loach (Misgurnus anguillicaudatus) differed in terms of their main haematological and physiological characteristics. Diploid and tetraploid fish were produced by crossing of natural diploids (2n x 2n) and natural tetraploids (4n x 4n), respectively. Triploid fish were produced by hybridization between diploid males and tetraploid females. The blood cells were significantly larger in polyploids, and the volumetric ratios of erythrocytes and leucocytes (thrombocyte and neutrophil) in tetraploids, triploids and diploids were consistent with the ploidy level ratio of 4:3:2. No significant differences were observed in haematocrit among polyploids. The erythrocyte count decreased with increased ploidy level, while total haemoglobin, mean cell volume, mean cellular haemoglobin content, and mean cell haemoglobin concentration all increased with increase in ploidy level. Erythrocyte osmotic brittleness declined in polyploids so that polyploid erythrocytes were more resistant to osmotic stress than diploid ones. Overall, loach with higher ploidy levels showed evidence of some advantages in haematological characteristics.     

Chicken mitochondrial cytochrome C oxidase subunit II: comparative analysis among the vertebrates

The chicken cytochrome c oxidase subunit II (COII) was cloned and sequenced. A comparison of the deduced chicken COII sequence with 4 other vertebrate counterparts revealed 64-66% amino acid sequence homology and 68-70% nucleotide sequence homology. Four peptide segments each of nine amino acids long are highly conserved across the 5 species. A redox-center was formed by three of these highly conserved domains, which include two invariant Cys and two invariant His residues for copper ion coordination, three strictly conserved Glu or Asp residues for cytochrome c binding, and highly conserved aromatic acid residues for electron transfer.     

Satellite sequence turnover in parthenogenetic systems: the apomictic triploid hybrid Bacillus lynceorum (Insecta, Phasmatodea)

In the genus Bacillus (Insecta, Phasmatodea) the Bag320 satellite DNAfamily is present in the bisexual B. grandii and in the related automicticnonhybrid B. atticus; it is lacking in the other bisexual taxon of thegenus, B. rossius. This family of highly repeated sequences was analyzedfor 11 populations of the apomictic triploid hybrid B. lynceorum. In theneighbor-joining dendrogram, B. lynceorum nucleotide sequences distribute,regardless of geographical origin, among two clusters, one also includingall clones of the three B. atticus races, and the other including sequencesof the B. grandii grandii subspecies. Thus, B. lynceorum is a trihybridtaxon: as the molecular approach definitively demonstrates, it embodies onehaploid complement each of both B. grandii grandii and B. atticus, whichmust be added to that of B. rossius. The contribution of the latter specieshas already been assessed on karyological and allozymic grounds. Astatistical analysis performed on p-distances shows that for the parentaltaxa, nucleotide substitution values are of comparable magnitudes at thepopulation level but differ at the subspecific level, being higher for thebisexual taxon. In the apomictic hybrid, atticus- and grandii grandii- likesequences coexist with significantly different p-distance values. For threeclones, the nucleotide compositions at the diagnostic loci suggest thatgene conversion can occur between atticus- and grandii grandii-likemonomers. On the whole, this supports bisexuality as a driving force invariant fixation and suggests that in Bacillus, different gametogeneticprocesses and different origins of the unisexuals are mirrored in genomicturnover rates of satellite DNA.