Postembryonic development of the parasitic amphipodHyperia galba

Hyperia galba Montagu is associated with gelatinous zooplankton as are many species of the Hyperiidea. The hosts preferred in the European seas are the large scyphomedusaeAurelia aurita, Chrysaora hysoscella, Rhizostoma pulmo, Cyanea capillata andCyanea lamarckii, which harbour the first developmental stages. The anamorphic development produces young that are incapable of swimming at the time of hatching. They are characterized by an embryonic abdomen without extremities and external segmentation; the eyes are not completely developed and the mouth is primitive lacking bristles, molar and incisor. The postembryonic development, described in detail, is subdivided into two phases: the pantochelis phase and the protopleon phase; the former comprises only one stage; the latter can be subdivided into four stages. In the course of postnatal development the larval organs are reduced and characters typical of the adult are gradually differentiated.H. galba plays an important role as obligatory endoparasite of scyphomedusae at least during the first stages of development; without a host this amphipod cannot survive, neither benthically nor in the plankton. The transition from life in the female's marsupium to endoparasitism in the jellyfish generally occurs during stage of the postembryonic development which is the first stage of the protopleon phase. The specific adaptations of its reproductive biology to a parasitic mode of life such as moult inhibition under starvation, development of larval organs and the behavioural patterns of the females as well as the young are described. Further, the influence of external factors such as temperature and food supply on the course of development is examined. Dedicated to Prof. Dr. H. Mergner on the occasion of his 70th birthday.     

Induction of mesodermal tissues by acidic and basic heparin binding growth factors

The inducing activity of two heparin binding growth factors HBGF-1 (prostate epithelial cell growth factor; acidic pI) and HBGF-2 (fibroblast growth factor; basic pI) from bovine brain has been tested on totipotent ectoderm from early amphibian (Xenopus laevis, Ambystoma mexicanum) embryos. Both factors induced, at high concentrations, mostly compact spheres surrounded by a non-epidermal epithelium. When the concentration or time of incubation was reduced, large muscle inductions frequently organized as somites were formed besides endothelial vesicles, mesenchyme and smaller areas of intestine-like epithelium. Further reduction of the concentrations or the time of incubation led to an increase in size and number of endothelium-lined vesicles and of mesenchyme, whereas the induction of muscle decreased. At still lower concentrations the overall rate of inductions decreased. The relationship of the growth factors to the vegetalizing factor from chicken embryos, dilution of which shows a similar shift in induced organs, is discussed. The present and previous experiments suggest that different mesodermal and endodermal tissues are induced by secondary interactions in which additional factors are involved. The induced organs derive from dorsal as well as from ventral mesoderm.     

Morphology of the female reproductive organs of the African lion (Panthera leo)

The topography and splanchnology of the reproductive organs of the African lioness were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs. The suspensory ligament was very well developed, originated in a fan‐like manner from the dorsolateral abdominal wall lateral to the kidney and extended up to a few centimetres cranial to the kidney. The proper ligament of the ovary as well as the round ligament was well developed. The round ligament inserted on the medial femoral fascia. The left ovary was bigger than the right. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended along the entire length. The urethral tuberculum as well as the urethral crest were well developed. The left uterine horn was longer than the right. The uterine tube was found to open directly into the tip of the uterine horn and not onto a papilla. The reproductive organs of the lioness resembled those of the domestic cat and dog but with some major differences.     

Early development of marine catfishes (Ariidae): from mouth brooding to the release of juveniles in nursery habitats

The development and allometric growth patterns of the ariid catfishes Cathorops spixii and Cathorops agassizii were studied from neurula embryos to juveniles. The ontogenetic sequence revealed that prior to hatching, embryos of both species are well developed, and their axial and appendicular skeletons are well ossified. Embryos of both species grow slowly longitudinally, but positively allometric growth (growth coefficient, β₁ > 1) was observed in head width and eye diameter. It is hypothesized that these growth patterns might be related to functional priorities for the development of sensory organs, such as the inner ears (otoliths), the Weberian apparatus, eyes and nostrils, during the embryonic period. The first appearance of vertebrae and otoliths, as well as the ossification of otoliths and the Weberian apparatus, occur earlier in embryos of C. agassizii than in embryos of C. spixii. After hatching, mouth‐brooded free embryos of both species grow isometrically. Negatively allometric growth was observed in head width and eye diameter during the yolk‐sac period, which is expected given that the sensory organs are already formed. Free embryos of C. agassizii are distinguishable from those of C. spixii by their larger eyes, longer snouts, longer heads and heavier yolk sacs. The end of the yolk‐sac period is characterized by a direct change from free embryo to juvenile, without a true larval period. The juveniles of the two species can also be distinguished from each other by the larger eyes of C. agassizii compared with C. spixii, as in adult fishes.     

FLORAL ANATOMY OF KRAMERIA LANCEOLATA

The anatomy of each of the series of floral organs of Krameria lanceolata was examined. The sepals are characterized by three main veins each, an undifferentiated mesophyll, and stomata on the upper epidermis. The fleshy petals are distinguished by their numerous veins as well as by palisade-like epidermal cells on the outer surface. The three partially united petals have each a single vein and long, narrow epidermal cells similar to those on other floral organs. The stamens are united at their bases and bear tetra-sporangiate, conical anthers. The gynoecium includes a sterile and a fertile carpel. In the receptacle the veins to the sepals and petals are separated by a wide gap; those to the petals and stamens, by a narrow gap. Anatomical characteristics of the flower dissociate Krameriaceae from the legumes with which they have frequently been thought to be allied.     

The role of nemertean cerebral organs in salinity stress tolerance re‐examined in Paranemertes peregrina coe (hoplonemertea: Monostilifera)

The role of the cerebral organs of Paranemertes in salinity stress tolerance was investigated by measuring the effect of cerebral organ removal on volume regulation, and by observing the effects of hypo‐osmotic media on the cytology of the cerebral organs. Removal of the cerebral organs decreases the capacity for volume regulation, however, a similar change is seen in sham‐operated worms, indicating that the decreased capacity for regulation is due to the operation itself and not to interference with a physiological role of the cerebral organs. Cytological changes caused by in vivo exposure to dilute sea water are similar to those seen in worms fixed in hypo‐osmotic fixative and therefore do not likely represent a coordinated response of the organs to salinity stress. Also, no exchange of material between the cerebral organs and the vascular system, as reported in some other species (Ling, 1970; Ferraris, 1979), was observed. We conclude that in Paranemertes, the cerebral organs are not involved in osmoregulation.     

A new genus and species of scorpionfly (Mecoptera) from Baltic amber,with an unusually developed postnotal organ

A new genus and species of fossil scorpionflies (Mecoptera) Baltipanorpa damzeni gen. et sp.n. is described from two well‐preserved male specimens in Baltic amber (middle Eocene: Lutetian). The most characteristic feature of the new taxon is an unusually developed postnotal organ on abdominal tergum IV. This is the most extremely developed example of this organ among Mecoptera and the only observation of notal and postnotal organs among fossil scorpionflies. The following combination of characters are provided to distinguish the new genus from other Panorpidae: Sc, short; R₁ and R₂ two‐branched; A₁ joins posterior margin of wing only at same level as fork of vein Rs; unusual shape of abdomen, abdominal segments I–IV strongly reduced, abdominal segment V elongate and widened, segments VII and VIII strongly elongate; notal and postnotal organs present, strongly developed process (postnotal organ) on tergum IV, unknown in all described extant and fossil scorpionflies. Different types of notal organs of Mecoptera are compared and their function and morphology are discussed. Morphological analysis of notal and postnotal organs in extant species permits us to conclude that B. damzeni sp.n. is characterized by the most developed and complex notal organs in all Mecoptera.     

A nuclear mutation blocking initiation of the lamina in leaves of Nicotiana syhestris

Isolation of a nuclear recessive mutation (lam-1) blocking initiation of the lamina in leaves of Nicotiana sylvestris Speg. et Comes is described. Histological analysis of the mutant apex demonstrates a defect in establishment of meristematic activity along the margins of emerging primordia, the earliest cytological event in lamina formation. Mutant leaves grow to their normal length (about 30 cm) but fail to expand. Transverse sections show that mutant leaves are essentially naked midribs, lacking the characteristic cell types of the wild-type mesophyll. In the absence of lateral expansion, all secondary veins develop along the longitudinal axis, producing abnormal parallel venation. The mutant is defective in phase transition and grows indefinitely as a juvenile vegetative rosette. Exogenous gibberellic acid induces rapid stem elongation and flowering, but does not correct the lamina defect, indicating that juvenile arrest is a pleiotropic consequence of a gibberellin deficiency in bladeless leaves. The calyx, corolla and gynoecium in mutant flowers show defects in lateral development, indicating that the lam-1 gene plays a crucial role in development of floral organs as well as leaves.Abbreviations GA gibberellin - GA₃ gibberellic acid - WT wildtype The technical assistance of Regan Perry is gratefully acknowledged.     

Reduced sialylation status in UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE)-deficient mice

Sialic acids are widely expressed as terminal carbohydrates on glycoconjugates of eukaryotic cells. They are involved in a variety of cellular functions, such as cell adhesion or signal recognition. The key enzyme of sialic acid biosynthesis is the bifunctional UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase (GNE), which catalyzes the first two steps of sialic acid biosynthesis in the cytosol. Previously, we have shown that inactivation of the GNE by gene targeting causes early embryonic lethality in mice, whereas heterozygous GNE-deficient mice are vital. In this study we compared the amount of membrane-bound sialic acids of wildtype mice with those of heterozygous GNE-deficient mice. For that we quantified membrane-bound sialic acid concentration in various organs of wildtype- and heterozygous GNE-deficient mice. We found an organ-specific reduction of membrane-bound sialic acids in heterozygous GNE-deficient mice. The overall reduction was 25%. Additionally, we analyzed transferrin and polysialylated neural cell adhesion molecule (NCAM) by one- or two-dimensional gel electrophoresis. Transferrin-expression was unchanged in heterozygous GNE-deficient mice; however the isoelectric point of transferrin was shifted towards basic pH, indicating a reduced sialylation. Furthermore, the expression of polysialic acids on NCAM was reduced in GNE-deficient mice. Daniel Gagiannis and André Orthmann have contributed equally to this work.     

Co-suppression of the petunia homeotic gene fbp2 affects the identity of the generative meristem

The function of the petunia MADS box gene fbp2 in the control of floral development has been investigated. Inhibition of fbp2 expression in transgenic plants by a co-suppression approach resulted in the development of highly aberrant flowers with modified whorl two, three and four organs. This mutant flower phenotype inherited as a single Mendelian trait. The flowers possess a green corolla which is reduced in size. Furthermore, the stamens are replaced by green petaloid structures and the inner gynoecial whorl is dramatically reduced. No ovules or placenta are formed and instead two new inflorescences developed in the axils of the carpels. These homeotic transformations are accompanied by a complete down-regulation of the petunia MADS box gene fbp6 which is highly homologous to the Arabidopsis and Antirrhinum genes agamous (ag) and plena (ple). In contrast to this, two other petunia MADS box genes, exclusively expressed in whorls two and three, are still transcribed. Our results indicate that the fbp2 gene belongs to a new class of morphogenesis genes involved in the determination of the central part of the generative meristem.     

Carcinoplacental Alkaline Phosphatase

Using HeLa TCRC-1, a cell line which is monophenotypic with respect to the Regan isoenzyme of alkaline phosphatase, we have examined the factors which influence its expression in relation to events of the cell cycle.
DNA synthesis is not required for hormone induction of the Regan isoenzyme as in the presence of hydroxyurea, a specific inhibitor of DNA synthesis, we found induction to occur. Additionally, when partially synchronised cells were allowed to leave the S period prior to hormone treatment, and hydroxyurea was added to prevent cells from entering the next S period, hormone induction of the Regan isoenzyme was still observed. This indicates that initiation of expression of hormone-induced carcinoplacental alkaline phosphatase occur prior to the DNA synthetic phase of the cell cycle.
We propose a hypothetical two-step mechanism of hormone induction to interpret the present findings in relation to previous results.     

Ultrastructure and functional morphology of the female reproductive organs inProtodrilus (Polychaeta,Annelida)

The morphology and function of the female reproductive organs in 6Protodrilus species are investigated by light- and transmission electron microscopy. Possible ways in which spermatozoa may enter the female coelom after leaving the spermatophore are discussed for species with and without special female reception organs. Only femaleP. rubropharyngeus andP. flavocapitatus have “dorsal organs” for spermatophore reception. The structure and function of these organs are described, as well as those of the oviduct found in 3 of the species investigated. The possible phylogenetic origin of gonoducts and different modes of oviposition within the genus are discussed. Finally, the high taxonomic significance of female traits such as dorsal organs, oviducts, cocoon glands and lateral ciliary rows in this genus is stressed.     

Vascular transport of auxins and cytokinins in Ricinus

Analyses of vascular saps supplying source and sink organs havedemonstrated the presence of major endogenous hormones and/or theirprecursors. Indol-3yl-acetic acid, a number of gibberellins, cytokininsand abscisic acid, as well as the precursor for ethylene production havebeen found in these vascular saps, allowing the sites of hormonalsynthesis and putative target tissues to be deduced. Exogenously appliedhormones are also readily loaded into these vascular pathways and may betranslocated over considerable distances from a point of application.Observations such as these indicate a possible co-ordination systembetween source and sink regulated by the synthesis and transport ofendogenous hormones. It is widely accepted that the partitioning ofassimilates between photosynthetic source organs and utilising sinkorgans is regulated by endogenous plant hormones. The key intermediatesteps involved in assimilate transport, such as phloem loading andunloading, have been shown to be responsive to applied hormones,although the role of endogenous hormones in these processes remainsessentially unresolved. Results of the analyses of vascular saps fromRicinus communis, which have been obtained using a range ofphysicochemical methods, are compared and contrasted with those obtainedby the application of exogenous hormones or their precursors. Theseresults are evaluated critically and interpreted in the light of currentmodels of source:sink regulatory processes and the long-distancetransport of auxins and cytokinins in higher plants.     

Reproductive effort in desert versus mediterranean crucifers: the allogamous Erucaria rostrata and E. hispanica and the autogamous Erophila minima

Components of the total sexual investment of plants growing under mediterranean climatic and edaphic conditions were compared with those of plants growing in the desert, in the closely related allogamous species pair Erucaria hispanica and E. rostrata and in populations of the autogamous species Erophila minima. In all cases lower total investment was evident in the desert plants. At the prezygotic phase it was expressed by (1) reduced production of flowers; (2) lower allocation to the production of male gametophytes and some floral organs; and (3) packaging of more ovules per ovary. The ratio of reproductive: vegetative biomass which was found to be greater in the desert plants and their lower pollen: ovule ratio are perhaps indicative of greater efficiency. Their smaller investment at the postzygotic phase was expressed in: (1) reduction in total numbers of fruits and seeds; (2) decrease in seed size and weight. Yet in the desert plants the number of seeds per total biomass was found to be significantly larger and fertility rates (seed-set per ovule, fruit-set per flower per plant) were equal to or greater than those in the mediterranean plants. The trends observed in this study in desert plants, which may result in more efficient exploitation of resources, are similar in the species involved, regardless of their breeding system-autogamous or allogamous.     

SPIRAL DEVELOPMENTAL PATTERNS IN THE STEM AND INFLORESCENCE OF LILIUM TIGRINUM

Extensive correlations in spirality were observed among vegetative and floral organs in Lilium tigrinum Ker. Organs involved were vegetative leaves, bracts, and bracteoles. These correlations varied in their degree of constancy depending upon the organs involved. The mature inflorescences of L. tigrinum appeared to fit the common definition of a raceme. In 67.3% of the flowers at node 3 on the raceme, the bract-bracteole spirals reversed the spiral of vegetative leaves on the stem. These reversals resembled those observed on essentially cymose inflorescences of certain members of the Caryophyllaceae. Cymose branching was found to be an invariable feature of the inflorescence of L. tigrinum when secondary flowers appear. The apparently indeterminate tips of inflorescence main axes were interpreted as exhibiting stages in progression from a basically determinate (cymose) inflorescence. It was concluded that the ancestors of L. tigrinum had well-developed cymose branching patterns in the inflorescence. Reversal of stem spirals by the bract-bracteole spirals at the apices of many inflorescences was considered to be the result of complete utilization of the inflorescence meristem. Explanations for those reversals were provided by the field theory and by the theory of the first available space.     

Sequence evolution and sex-specific expression patterns of the C class floral identity gene, <Emphasis Type="Italic">SpAGAMOUS</Emphasis>, in dioecious <Emphasis Type="Italic">Spinacia oleracea</Emphasis> L

Development in dioecious cultivated spinach, Spinacia oleracea, is distinguished by the absence of alternative reproductive organ primordia in male and female flowers. Given the highly derived floral developmental program in spinach, we wished to characterize a spinach C class floral identity gene and to determine the patterns of sequence evolution as well as compare the spatial and temporal expression patterns with those of AGAMOUS. The isolated cDNA sequence clusters phylogenetically within the AGAMOUS/FARINELLI C class clade. In comparison with the SLM1 sequence from the related Silene latifolia, amino acid replacements are highly conservative and non-randomly distributed, being predominantly found in hinge regions or on exposed surfaces of helices. The spinach gene (SpAGAMOUS) appears to be exclusively expressed in reproductive tissues and not in vegetative organs. Initial expression of SpAGAMOUS is similar in male and female floral primordia. However, upon initiation of the first whorl organs, SpAGAMOUS becomes restricted to meristemic regions from which the reproductive primordia will develop. This results in an early gender-specific pattern. Thus, the spinach C class gene is differentially expressed prior to reproductive organ development and is, at least, correlated with, if not directly involved in, the sexual dimorphism in spinach.Electronic Supplementary Material Supplementary material is available for this article at     

Selectivity of the peripheral auditory system of spadefoot toads (Scaphiopus couchi) for sounds of biological significance

Summary Scaphiopus couchi is a primitive anuran whose vocal repertoire consists of a mating call and a release call. The two calls are distinct and differ in trill rate. Reception of airborne sound is achieved by means of a poorly differentiated region of skin on the head which serves as an eardrum.Whereas more modern anurans possessthree distinct types of auditory nerve fibers, spadefoot toads possess onlytwo types: a low-frequency-sensitive group which exhibits tone-on-tone inhibition and a high-frequency-sensitive group which is not inhibitable. The sharpness of frequency tuning of primary fibers in each group is comparable to more advanced vertebrate species. While the response properties of auditory fibers in the high-frequency-sensitive group are well matched to the spectral and temporal features in the spadefoot's mating call and release call, the low-frequency-sensitive fibers do not respond to these calls. Instead they may be involved in detection of bodily transmitted sounds during clasping, as well as other low-frequency sounds in the environment. The two groups of auditory fibers probably derive from separate auditory organs within the inner ear. Thresholds of auditory nerve fibers in spadefoot toads are relatively poorer than in more advanced anurans, which likely is due to their less developed eardrum. The role of tone-on-tone inhibition in the peripheral auditory system is questioned with regard to its significance in processing sounds of biological value.We wish to dedicate this paper to Jasper J. Loftus-Hills who was killed in a tragic accident near Austin, Texas on June 11, 1974. His post-doctoral appointment in our laboratory and his assistance in collecting spadefoot toads in the field recall fond memories.We also wish to thank R. Sage for helping us collect animals and W. F. Blair for supplying tape recordings ofScaphiopus mating calls. The assistance of J. Paton in photographing the animal in Fig. 1 is gratefully appreciated. This research was supported by the U.S. Public Health Service (NIH Research Grant NS-09244) and the National Science Foundation (Grant GB-18836); travel expenses involved in collecting animals were supported by a Cornell University Research Grant.