Development of cephalic neural crest cells in embryos of Lampetra japonica, with special reference to the evolution of the jaw

Neural crest cells contribute extensively to vertebrate head morphogenesis and their origin is an important question to address in understanding the evolution of the craniate head. The distribution pattern of cephalic crest cells was examined in embryos of one of the living agnathan vertebrates, Lampetra japonica. The initial appearance of putative crest cells was observed on the dorsal aspect of the neural rod at stage 20.5 and ventral expansion of these cells was first seen at the level of rostral somites. As in gnathostomes, cephalic crest cells migrate beneath the surface ectoderm and form three major cell populations, each being separated at the levels of rhombomeres (r) 3 and r5. The neural crest seems initially to be produced at all neuraxial levels except for the rostral-most area, and cephalic crest cells are secondarily excluded from levels r3 and r5. Such a pattern of crest cell distribution prefigures the morphology of the cranial nerve anlage. The second or middle crest cell population passes medial to the otocyst, implying that the otocyst does not serve as a barrier to separate the crest cell populations. The three cephalic crest cell populations fill the pharyngeal arch ventrally, covering the pharyngeal mesoderm laterally with the rostral-most population covering the premandibular region and mandibular arch. The third cell population is equivalent to the circumpharyngeal crest cells in the chick, and its influx into the pharyngeal region precedes the formation of postotic pharyngeal arches. Focal injection of DiI revealed the existence of an anteroposterior organization in the neural crest at the neurular stage, destined for each pharyngeal region. The crest cells derived from the posterior midbrain that express the LjOtxA gene, the Otx2 cognate, were shown to migrate into the mandibular arch, a pattern which is identical to gnathostome embryos. It was concluded that the head region of the lamprey embryo shares a common set of morphological characters with gnathostome embryos and that the morphological deviation of the mandibular arch between the gnathostomes and the lamprey is not based on the early embryonic patterning.     

The cephalic arterial system in carnivores, with special reference to the systematic classification

The cephalic arterial pattern in 53 fissipeds, representing all the classical families, is described on the basis of corrosion casts prepared by means of a special plastic injection and corrosion technique. The results are discussed on an ontogenetic and phylogenetic basis and related to current theories on the systematic classification of fissipeds at a higher taxonomic level (infraorders or superfamilies). In this respect, especially the systematic position of the canids and hyaenids in relation to the felids is discussed, the greatest importance being attached to the contribution of the external carotid artery system to the intracranial circulation. Also the very specific cephalic arterial pattern in the herpestines, one of the two viverrid subfamilies studied, is emphasized.     

Comparative observations on AChE distribution in pancreas of some amphibians,reptiles and birds,with special reference to the islets of langerhans

Summary AChE activity in pancreas of some amphibians, reptiles and birds was investigated with light microscope using Karnovsky's technique.A nervous and an extranervous localization of the enzyme showing considerable qualitative and quantitative differences depending on the systematic group, could be discerned. Pancreatic peripheral cholinergic autonomic system comprises nerve fibers and perikarya. The latter seem to occur in newt and frogs as Cajal's interstitial cells (CIC) and are undoubtedly present in birds as CIC and as ganglionic cells. In lizard and snakes they were not present.The extranervous localization of AChE activity was observed in islet cells in frogs, lizards and snakes, also in the walls of blood vessels of all investigated poikilotherms.The findings are compared with results previously obtained in mammalian pancreas or in other organs. Some hypotheses on the physiological significance of enzyme presence in endocrine cells, as well as their belonging to APUD cell series are discussed.This work was supported by a fellowship of the Alexander von Humboldt-Stiftung, Bonn-Bad Godesberg and by the Deutsche Forschungsgemeinschaft (La 229-3). The author expresses his thanks to Prof. Dr. R. H. Lange for scientific advice.     

Histochemical differentiation of endocrine gastrointestinal cells in test animals, with special reference to chicken embryos.

Based upon the characteristics of argent-affinity and argyrophilia and the application of specific immune histochemical methods, endocrine cells can be differentiated in the most prominent species of test animals. These methods are demonstrated in chicken embryos, because embryological studies made in order to reveal the still unknown endodermal or neuroectodermal origin of these cells are highly important.     

Pancreatic APUD cells in older chick embryos,with special reference to their identity

Summary Pancreatic APUD cells showing formaldehyde-induced fluorescence in Black Australorp chick embryos of nine to eighteen days of incubation, proved, on subsequent staining and silver impregnation, to be A, B, D and, from sixteen days, enterochromaffin (EC) cells. EC and D cells were scattered in the exocrine parenchyma, the latter cells increasing with time. Some groups of B cells were associated with large A islets from the ninth day of incubation onwards. The composition of A islets (A and some D cells) and B islets (B and some D cells) and the distribution attained (A islets in the splenic and third lobes; B islets in all lobes), accords with the situation reported for adults.     

Superovulation in nonseasonal Japanese native goats, with special reference to the developmental progression of embryos

Treatment for superovulation with pregnant mare serum gonadotropin (PMSG) and follicle stimulating hormone (FSH) was carried out in nonseasonal breeder Japanese goats which are widely used as a substitute model for cattle in various studies in Japan. The proportion of females that came into estrus (93 and 99%) and the interval between PGF(2) administration and estrus (1.5 to 2.0 days) did not differ between females treated with PMSG and those treated with FSH. The number of normal embryos recovered was significantly higher (P<0.01) in FSH-treated (9.4 +/- 5.6) femals than in PMSG-treated females (5.7 +/- 4.4). The developmental stage of embryos recovered from 1.0 to 8.5 at 0.5-d intervals after mating is also described. The development to the two-cell, four-cell, eight-cell, morula, blastocyst and zona-free blastocyst stage was first observed 1.5, 2.5, 5.0 to 5.5, 6.0 and 6.5 d, respectively, after human chorionic gonadotropin (hCG) injection.     

Brains of Vespertilionids II. Vespertilioninae with special reference to Tylonycteris

As shown in Part I, the Vespertilioninae have on the average the lowest encephalization index (EI) of all the Vespertilionid subfamilies available, and the average size indices (Sis) of most of their brain parts are also lowest. There are, however, clear differences between the genera. The highest indices for the total brain and for many brain parts (OBL, DIE, TEL, PAL, SEP, STR, SCH) were found in Myotis, the highest Sis for NEG and MES in Scotophilus, for CER in Lasiurus, for BOL in Rhogeessa, and for HIP in Cbalinolobus. The lowest values for all brain parts except BOL were found in Tylonycteris (for BOL in Glauconycteris). The average EI of the flat-headed bamboo bats Tylonycteris pachypus and T. robustula was 60, i. e., ²/₅ less than that of the non-Tylonycteris Vespertilionids, which, as the reference group, have an average EI of 100. The brain size reduction may well be related to the adaptation to extreme flat-headedness. The amount of reduction in the various brain parts differs: it is strongest (about ¹/₂) in higher but more dispensable brain parts (STR, HIP, NEO) and distinctly lower (about ¹/₄) in structures closely involved in the fundamental vegetative functions (OBL, MES). Genera with conservative skull characteristics may have derivative characteristics of the brains, and vice versa.     

Current usage of nomenclature for parasitic diseases, with special reference to those involving arthropods

Terminological confusion has been aggravated by efforts to develop a standardized nomenclature for parasitic diseases (SNOPAD) arising from the proposal by Kassai et al., 1988) for a standardized nomenclature of animal diseases (SNOAPAD). To restabilize international nomenclature of parasitic diseases it is recommended that, whenever appropriate, names should follow the 'International Nomenclature of Diseases' (IND) compiled by the Council for International Organizations for Medical Sciences (CIOMS/WHO, 1987). For diseases not included in IND, familiarity should guide the choice of name: traditional English language names of diseases should be preferred, e.g. 'malaria', 'scabies' or, for parasitic diseases having no traditional name, the taxonomic name of the causative organism should be applied, e.g. 'Brugia timori microfilaraemia'; 'Plasmodium malariae infection'; 'Simulium allergy'--instead of the generic derivatives proposed by SNOPAD, i.e. brugiosis, plasmodiosis and simuliidosis, respectively. For names of new diseases or those rarely mentioned, the suffix -osis would normally take precedence. Generally, the name of choice for any disease in any language should be the vernacular term, with commonest English usage preferred for international communication, and publications should include synonyms in the list of keywords.     

Contribution to ITS phylogeny of the Brassicaceae, with special reference to some Asian taxa

Sequence data from the nuclear ribosomal internal transcribed spacer (ITS) region for 189 accessions representing 184 species in 121 genera of Brassicaceae were used to determine monophyly of tribes and genera, tribal boundaries, and component genera. Parsimony analysis and Bayesian inference suggest that the tribes Camelineae and Arabideae are polyphyletic and should be subdivided into smaller tribes. The study also supports the recent recognition of the new tribes Aphragmeae, Biscutelleae, Buniadeae, Calepineae, Conringieae, Dontostemoneae, Erysimeae, Malcolmieae, Megacarpaeeae, and Turritideae. The data argue for the placement of Borodinia in the tribe Boechereae, Litwinowia and Pseudoclausia in the Chorisporeae, Atelanthera and Streptoloma in the Euclidieae, and Megacarpaea and Pugionium in the Megacarpaeeae, and exclusion of Asperuginoides, Didymophysa, and Ptilotrichum from the Alysseae, Macropodium, Pseudoturritis, and Stevenia from the Arabideae, and Crucihimalaya, Irenepharsus, Pachycladon, and Turritis from the Camelineae. Finally, the findings support the expansion of Stevenia to include both Berteroella and Ptilotrichum, Sterigmostemum to include Oreoloma and one species of Anchonium, Crucihimalaya to include Transberingia and several species of Arabis, and Parrya to include Pseudoclausia. The data also suggest that Calymmatium and Olimarabidopsis may be congeneric.