The female millipede reproductive system and its dynamical changes, with a partial review.

The structure of the millipede female reproductive system is described, discussed and reviewed. The different reproductive systems of female millipedes are illustrated, some of them for the first time. The various families appear to have developed several different structures of this organ. Nevertheless, more detailed studies on the female reproductive systems, especially the changes taking place during the oogenetic cycle, are needed in all millipede orders. Only this way can it be ascertained, whether ovarian structures observed are not only a transitional phase. This was done in two millipedes, Archispirostreptus tumuliporus judaicus (Attems 1927) and Catamicrophyllum caifanum (Verhoeff 1900), where these changes were followed for a longer period of time and on a large number of specimens. The evolutionary meaning of this diversity in reproductive systems cannot be clarified at the present time, nor its significance for the survival of the such diversified forms in the Class Diplopoda.

Reproductive system of female scorpion: a partial review.

The female scorpion ovariuterus was examined in 10 scorpion species belonging to five families: Buthidae, Vaejovidae, Scorpionidae, Urodacidae, and Diplocentridae. Two main patterns of development are known in scorpions: (1) The apoikogenic type with an ovariuterus containing yolk-rich eggs housed in follicles. This type is found in many scorpion taxa (largely buthids). A peculiar case of apoikogenic ovariuterus is a "beaded" ovariuterus where most of the ova's embryogenesis takes place inside the ovariuterus rather than on pedicels situated on the external wall of the ovariuterus as in most buthids. This type is found in a few scorpion species. (2) The katoikogenic type with an ovariuterus where the embryo develops in a diverticulum composed of four parts: a stalk (pedicel), a thickened collar, a conical portion containing the ovum, and an appendix containing the oral feeding apparatus where the embryos' chelicerae grip a "teat"-like structure, described in four families: Hemiscorpiidae, Scorpionidae, Urodacidae, and Diplocentridae. There are three kinds of diverticulae: small rudimentary finger-like diverticulae, embryonic (ED) large projections, and postpartum diverticulae (PPD) empty diverticulae, which are remnants after parturition. The subject is reviewed and its bearing on reproduction in scorpions are discussed.

Cutaneous glands in the Australian hylid Litoria caerulea (Amphibia, Hylidae).

Ultrastructure of cutaneous glands is described in the Australian hylid Litoria caerulea. Three main types of glands could be distinguished in both ventral and dorsal skin: mucous, serous or granular, and lipid glands. Both mucous, and to some extent, serous glands show a PAS-positive reaction. Some of the granular-serous glands react to lipid staining. In addition, a very large gland confined to the dorsal skin of the head reacts to lipid staining. Apparently more than one type of dermal gland is involved in lipid secretion. The subject of skin lipid secretion is discussed in relation to the ecophysiological adaptations of this xeric-inhabiting frog.

Changes in numbers and dimensions of glomeruli during metamorphosis of Pelobates syriacus (Anura; Pelobatidae).

Changes in glomerular numbers and volume were followed throughout five ontogenetic stages of Pelobates syriacus (Anura, Pelobatidae). The number of glomeruli increased markedly between the 2-legged and the 4-legged tadpole stages. In the post-metamorphic stages the number of glomeruli was about twice their number during the tadpole stages. Glomerular volume peaked during the 2-legged tadpole stage, when the tadpole reached its maximal size, and dropped thereafter. There is some evidence to indicate that the number of glomeruli in post-metamorphic P. syriacus increased during growth thus indicating perhaps an increase in their functional importance. The number was still lower than that reported for some other anurans, more similar to the numbers given for representative urodeles, however, the latter have considerably larger glomeruli. Two main factors appear to be involved in regulating numbers and volume of glomeruli in frogs. The ontogenetic changes during metamorphosis affect both glomerular numbers and volume, whereas post-metamorphic growth affected only the glomerular numbers.

Ovariuterus of Pandinus imperator, Koch (Scorpiones; Scorpionidae): comparison of virgin female with mother.

The ovariuterus of the female Pandinus imperator Koch (Scorpiones; Scorpionidae), was compared in a virgin female and a female that had previously given birth at least twice (in the laboratory). The virgin female did not have any embryonic diverticulae (Ed) nor did it have any degenerated, post-partum diverticulae (Dd), whereas in the mother scorpion several Dd were clearly seen on the ovariuterus. This latter female lacked any embryonic diverticulae (Ed). The number of the Dd corresponds well with the number of juveniles in the last brood born to that female during the previous year. Based on the total number of diverticula observed, and the average known litter size, it is suggested that these long-lived scorpions are potentially able to breed at least six times during their lifetime. Since they apparently do not breed in consecutive years (as is evident from the lack of Ed in the female that had bred a year before) and perhaps only every alternate year, they are capable of breeding for 12 years. If a litter amounts to about 25 young, a female is capable of producing 150 young. As it takes about three years to mature from nymph to adult, the life expectancy in this species is therefore about 15 years, by a conservative estimate.

Unusual cell ultrastructure in ventral epidermis of the African reed frog Hyperolius viridiflavus, (Anura; Hyperoliidae).

The stratum corneum of the epidermis of Hyperolius viridiflavus contains several replacement layers. The outer layer is covered by mucopolysaccharide secretion. H. viridiflavus in their dry phase do not moult the sloughed off layers; these remain attached to the stratum corneum. Long and slender pillar-like cells situated under the stratum corneum extend through the stratum granulosum, stratum germinativum, and the basement membrane into the dermis. These cells abound in tonofilaments. Flask-shaped cells rich in mitochondria, reaching under the stratum corneum, extend into the stratum granulosum. They show delicate, membranous infoldings in their neck-like apical part. Granule-cells, arranged in 2 or 3 layers are situated in the stratum granulosum between the stratum corneum and germinativum. The germinative cells are large and separated from each other by wide intercellular spaces. ATPase activity was localized cytochemically in the baso-lateral cell membranes bordering with the intercellular spaces under the stratum corneum.

Ultrastructure of ventral epidermis in the terrestrial and aquatic phases of the newt Triturus vittatus (Jenyns).

The ultrastructure of the ventral epidermis is described in the aquatic and terrestrial phases of the newt Triturus vittatus (Jenyns). In both phases, the stratum corneum is characterized by a large number of keratinocytes and bundles of tonofilaments. Mitochondria-rich flask cells were found in both phases. The main difference was found in the abundant tuberculi on the surface, and in the number of stratum corneum replacement layers found in the terrestrial phase. The epidermis of the aquatic phase did not show any resemblance to the aquatic larval stage, thus no Leydig cells could be found.

Structure of gill epithelium in Triturus vittatus larvae.

The gill epithelium ultrastructure of the larval stage of the newt, Triturus vittatus, has been studied. Two layers can be distinguished: an outer layer and an inner layer. The outer layer is composed of four cell types: pavement cells, ciliary cells, mitochondria-rich cells (MRC) and round, granule-containing cells. Large numbers of vesicles containing PAS (+) material can be seen in the apical part of the pavement cells. Their outer face is covered with short microvilli. The ciliary cells contain many mitochondria and their surface is adorned with cilia. The mitochondria-rich cells are fully packed with mitochondria. They are unique in having elaborate tubular membranous infoldings, which open on to the surface in a net-like arrangement of long, slender microvilli. Finally, the outer layer contains very few (29 cells in a 35 mm length tissue, or 0.8/1 mm) rounded, granule-containing cells. These granules, of various sizes and shapes, are PAS (-) and contain elaborate Golgi figures. The inner layer is characterized by the presence of numerous, large Leydig cells; 19.56 cells/mm tissue. Finally, large, germinative cells rich in tonofilaments are situated on the basement membrane.

Oogenesis and the ovarian cycle in Salamandra salamandra infraimmaculata Mertens (Amphibia; Urodela; Salamandridae) in fringe areas of the taxon's distribution.

Reproductive cycle and oogenesis were studied in specimens of Salamandra salamandra infraimmaculata Mertens that inhabit fringe areas of the taxon's distribution in the Mediterranean region. Both ovarian mass and length are correlated significantly with body mass and length. Ovarian length is also correlated with the number of oocytes. During the oogenetic cycle six stages in oocyte development were recognized. Three occur during previtellogenesis: stage 1, in which oogonia divide and form cell nests; stage 2 in which oogonia differentiate into oocytes; and stage 3, in which the oocyte cytoplasm increases in volume. In the vitellogenic phase two additional stages, 4 and 5, were recognized: stage 4, in which lipid accumulates in vacuoles in the periphery followed by the appearance of yolk platelets near the cytoplasmic margin; and stage 5, in which oocyte volume increases rapidly due to increased number of yolk platelets until it reaches its maximal size. During postvitellogenesis one stage was recognized: stage 6, in which the beginning of maturation is characterized by movement of the nucleus toward the animal pole. Oogenesis continues year-round. The first four stages were seen in all ovaries examined. The ovarian cycle is independent of season and reproductive stage apart from the number of mature, postvitellogenic oocytes that increases following gestation toward the beginning of spring (March-April). J. Morphol 231:149-160, 1997. © 1997 Wiley-Liss, Inc.

A different oogenetic pattern in a US apoikogenous scorpion, Vaejovis spinigerus (Scorpiones, Vaejovidae).

The ovariuterus of the scorpion Vaejovis spinigerus (Scorpiones, Vaejovidae) differs from that of all other apoikogenic species studied so far in that the oocytes mature inside, rather than on the outer surface, of the ovariuterus tubes. Only the small, second and third oocyte generations are situated on the outer surface, sometimes even on top, of the mature oocytes. This oogenetic pattern has so far not been described in any other scorpion species. Since no males were found in the populations studied here, this species can be assumed to be parthenogenetic. However, this point needs more concrete proof.

Hormonal effect on the osmotic, electrolyte and nitrogen balance in terrestrial Amphibia.

Two main hormones regulate water balance in amphibian. First, mesotocin (MT) acting as a diuretic agent, and second arginine vasotocin (AVT) being an anti-diuretic hormone. In addition, prolactin (PRL), aldosterone, corticosterone, angiotensin II and atriunatriuretic hormones, play a role too in regulating water and ion balance. The hormones affect the epidermis and bladder permeability to water and ions as well as the kidney through the control of the glomerular filtration rate (GFR). The main questions concern the presence and action of these hormones during the amphibian's life history. Are they present in both larval and adult stages? Are these hormones being synthesized in both aquatic and terrestrial adult phases? Under what circumstances are they being stored or released? Would the target organs (epidermis, bladder, kidney) respond in a similar way during all periods? The problem is the fact that under most circumstances an amphibian while in an aquatic environment responds physiologically differently than when on land. Only partial information concerning hormone presence, release and control of water balance is available at the moment, and even that is fragmentary and based on only a very small number of amphibian species.

The female reproductive system of the eastern Australian scorpion.

The reproductive system of the female Urodacus manicatus (Scorpionidae) is described. Situated on the ventral side of the ovariuterus tubes are buds and diverticulae belonging to three developmental phases: (1) Bud-like, rudimentary diverticulae that will form future generations. (2) Embryonic diverticulae that will house the present generation. (3) Degenerating (= 'post-partum') diverticulae that contained the previous generation of juveniles just born. The smallest buds could be identified only by scanning electron microscopy of the ovariuterus tube. The various diverticulae were counted and their dimensions were measured. Based on the average number of the embryonic diverticulae, it appears that the average number of young that can be produced by a female during a single parturition is 16.8. This number does not appear to increase significantly with the growth of the female.

Oosorption and oocyte loss in a terrestrial isopod under stressful conditions.

An increased number of resorbed oocytes was observed in ovaries of terrestrial isopods which were kept under different experimental temperature and photophase regimes compared with those observed in the natural population. Regardless of the nature of the stimulus: high or low temperature or long and short photophases, the female always responded through oosorption. In an iteroparous species such as Porcellio ficulneus B.-L., recruitment of resources for future utilization could be its main response to adverse ambient conditions.

Developmental changes in the heterocellular epidermis of Pelobates syriacus integument.

Changes in characteristic components of the skin epidermis of the large tadpole of Pelobates syriacus were studied throughout its development. The fate of two specific cells in the skin epidermis was followed, from the young tadpole to the adult was studied. It was found that flask-shaped type cells in the tadpole epidermis which are PAS-positive, stain with peanut lectin (PNA). There is no detectable band 3 in the premetamorphosed stages, and mitochondria-rich cells are very rare. This pattern of staining changes completely upon metamorphosis: the PAS-positive cells, specific to the tadpole epidermis disappear, and the mitochondria-rich (MR) cells in the adult skin epithelium react with polyclonal anti-band 3 antibody. Western blot analysis showed the presence of a band 3-like protein of about 95 kDa, only in the adult epithelial extract, corroborating the immunocytochemical observations. The finding of the presence of band 3-like protein in the MR cells of Pelobates, is similar to the observations made in the skin of other amphibian species. On the other hand, the binding of peanut lectin to MR cells is species-specific, since it does not react with the MR cells in the skin epithelium of Pelobates syriacus.

Carbonic anhydrase cytochemistry in mitochondria-rich cells of salamander larvae gill epithelium as related to age and H+ and Na+ concentrations.

Carbonic anhydrase (CAH) was localized in the mitochondria-rich cells (MRC) of 1-week-old salamander larvae gill epithelium, in both MRC and pavement cells of 6-week-old larvae, and in regenerated stems of previously amputated gills. CAH activity of the MRC was measured quantitatively using a microscope densitometric technique. Changes in CAH activity per cell and changes in the numbers of CAH-positive MRC were followed under different H+ and Na+ concentrations at the two age groups. CAH activity per cell increased with age, whereas the numbers of CAH-positive MRC dropped. CAH activity per cell in the 1-week-old age group reached maximal values at pH 7.4 and stayed relatively high in the more alkaline media. Moderate increases of Na+ concentrations had small but significant effects on increasing CAH activity of gill MRC. When taking into consideration not only the changes in cellular activity but also the changes in the number of CAH-positive cells under the different acclimation media, an activity index (ICAH) was calculated. Thus, the ICAH in the 1-week-old was found to be dependent on the decline of ambient H+ concentrations (expressed as increasing pH), reaching maximal effect at pH 8.0. On the other hand, raising the Na+ concentrations of the acclimation media to 110 and 220 mOsm/liter caused a maximal inhibition of tissue CAH activity as expressed by ICAH. In conclusion, it is suggested that salamander larvae gill MRC take part in the adaptation of the larvae to changing H+ concentrations of their milieu rather than in their adaptation to changes in its osmolality.

Water balance of five amphibian species at different stages and phases, as affected by hypophysial hormones.

Five amphibian species were studied for the effect of hypophysial hormones on their water balance. The species were three anurans, Rana ridibunda, Bufo viridis and Pelobates syriacus, and two urodeles Salamandra salamandra and Triturus vittatus. In the first four species different stages of development were studied, in the newt both the terrestrial and aquatic phases of the adult were examined. The hormones used were oxytocin (OXY), arginine vasotocin (AVT) and prolactin (PL). Oxytocin caused most water retention when compared with the other hormones, especially responding were juveniles of Rana and Bufo, but also the terrestrial phase of the adult newt Triturus. Arginine vasotocin affected mostly juvenile Pelobates. Prolactin caused water retention in juvenile Rana and in the terrestrial phase of Triturus. In general the hormones affected the juvenile stages more than either larvae or adults.

Ultrastructural studies of the epidermal leydig cell in larvae of Salamandra salamandra (caudata, salamandrida).

Epidermal Leydig cells observed in the ventral epidermis of Salamandra salamandra larvae from birth until metamorphosis are characterized by large vesicles and a supporting Langerhans net. They decline in number after birth and disappear entirely after metamorphosis. The cells change in structure and become larger, thus indicating a process of degeneration. The Leydig cells are continuously removed by macrophagelike cells after birth.

Changes in structure of ventral epidermis of Rana ridibunda during metamorphosis.

The organisation of the ventral epidermis organisation was followed throughout ontogenesis in Rana ridibunda. Epidermis of tadpoles with 2-3 limbs was organised into two layers: a stratum germinativum consisting of elongated columnar cells, and an outer stratum corneum consisting of two types of cuboid cells. Two types of cells can be distinguished; they are a light (clear) cell and a dark (dense) cell. In the 4-legged tadpoles the stratum corneum cells start to flatten and a replacement layer appeared underneath. A well-defined stratum germinativum is found and within it, epidermal glands. Moulting took place for the first time in tadpoles just before metamorphosis, and a well-organised stratum granulosum was formed still containing the two main types of epidermal glands. The flask cells appear in the juveniles for the first time, greatly increasing in numbers in the adult epidermis.

Ultrastructure of epidermis of Salamandra salamandra followed throughout ontogenesis.

Ventral epidermal ultrastructure of the amphibian urodele Salamandra salamandra is described and followed throughout its life cycle. Tadpoles were divided into five categories on the basis of the organization of their epidermis and the ultrastructure of its cells. In newly hatched tadpoles the epidermis is arranged in two layers and four types of cells were recognized. The number of epidermal layers increases in the metamorphosing tadpole. At this stage the layers become organized in four strata. Metamorphosis involves the disappearance of some cell types and the appearance of others, typical of the adult epidermis. The significance of these ontogenetic changes in epidermal ultrastructure is discussed in respect to aquatic and terrestrial life habits.