The ultrastructure of the integument of the American eel,Anguilla rostrata

Summary The morphology and ultrastructure of the lateral body integument of the leptocephalus, glass eel, pigmented elver, and adult stages of the American eel, Anguilla rostrata, were examined with light and electron microscopy. The integument consists of an epidermis separated by a basal lamina from the underlying dermis. Three cell types are present in the epidermis in all stages. Filament-containing cells, which are the principal structural cell type, are increasingly numerous at each stage. Mucous cells, which secrete the mucous that compose the mucous surface coat, are also more numerous in each subsequent stage and are more numerous in the anterior lateral body epidermis than in the posterior lateral body epidermis of the adult. Club cells, whose function is unknown, are most numerous in the glass eel and pigmented elver. Chloride cells are common in the leptocephalus which is marine and infrequent in the glass eel. They are not present in the pigmented elver and adult which inhabit estuaries and fresh-water. Lymphocytes and melanocytes are also present in some stages. The dermis comprises two layers: a layer of collagenous lamellae, the stratum compactum, and an underlying layer of loose connective tissue, the stratum spongiosum.There is a progressive increase in epidermal thickness at each stage which is paralleled by an increase in the thickness of the stratum compactum. Rudimentary scales are present in the dermis of the adult. The increase in the number of epidermal filament-containing cells, epidermal thickness and stratum compactum thickness is correlated with an increased need for protection from abrasion and mechanical damage as the eel moves from a pelagic, oceanic habitat to a benthic, freshwater habitat. The increase in mucous cell numbers is likewise correlated with an increased need for the protective and anti-bacterial action of the mucous surface coat in the freshwater environment.This investigation was supported by NIH research grant NS-11276 from National Institute of Neurological Diseases and Stroke to Dr. J.D. McCleave and by N.S.F. Grant GD 38933 to the Bermuda Biological Station, St. Georges West, Bermuda. Bermuda Biological Station Contribution No. 668     

Ultrastructural studies on prolactin and growth hormone cells in Anguilla pituitaries in vitro

Summary Eel hemi-pituitaries were cultured in vitro on high or low sodium media which are known to affect differentially prolactin and growth hormone release. Ultrastructural examination of the prolactin cells after 24 h culture showed the Golgi bodies were markedly more abundant and widely distributed in hemi-pituitaries from the low sodium medium. Secretory granule release profiles and dense bodies were also more frequent, but the percentage of the cytoplasmic volume occupied by secretory granules was lower than on the high sodium medium. RER was only slightly modified. Significant differences were noted in the shape and processes of the non-granulated (stellate) cells of the RPD, but there were only slight differences in the ultrastructure of the somatotropes.     

Ultrastructural studies on prolactin and growth hormone cells in Anguilla pituitaries in long term cultures

Summary Eel hemi-pituitaries were cultured in vitro on high or low sodium media, previously shown to affect differentially prolactin and growth hormone release. After 6 days culture, there were marked differences in the ultrastructure of both prolactin and growth hormone cells from the two groups. Morphometric data on the prolactin cells from SW-adapted eels showed a greater abundance of RER and paucity of secretory granules in cells from the low sodium medium. The size of the Golgi apparatus and the number of exocytosed secretory granules did not differ markedly between experimental groups, in contrast to previous findings on short-term cultures. Differences in the profile diameters of secretory granules are recorded between the experimental groups and the pattern differs markedly from that previously recorded for short-term cultures. The growth hormone cells from low sodium media were characterised by abundant, vesiculated RER, a prominent Golgi apparatus (in SW-adapted animals) and relatively few secretory granules. The activity of these growth hormone cells is in marked contrast to previous findings relating to short-term cultures. The shape and size of the non-granulated (stellate) cells of the RPD was again affected by the osmotic pressure of the medium.I should like to thank Mr. P.F. Hire for his photographic assistance     

Integrative taxonomy, systematics and distribution of the genus Eligmodontia (Rodentia, Cricetidae, Sigmodontinae) in the temperate Monte Desert of Argentina

The systematics and distribution of South American sigmodontine rodents a matter of continuous revision and debate. The silky mice, genus Eligmodontia Cuvier, 1837, are among the most specialized murid rodents endemic to South America and its diversification for desert existence is associated with the uplift of the Andes and the early development of arid landscapes. Aiming to clarify the systematics of the species of silky mice occurring in the driest portion of the temperate Monte Desert in Argentina, qualitative and quantitative external and cranial characters, cytogenetics and molecular relationships, were studied. We characterized three karyotypes of Eligmodontia; two of which are described for the first time, and allocated them to previously named species. E. moreni Thomas, 1896 (2n=52 and FN=50), E. typus Cuvier, 1837 (2n=44 and FN=44) and E. marica Thomas, 1918. The later shows the same diploid number of E. typus, but its X—chromosome is not METACENTRIC but ACROCENTRIC . A discriminant analysis of external and cranial data separates E. moreni from E. typus and E. marica. Whereas these last ones show some degree of overlap. The morphological and chromosomal differentiation of Eligmodontia is sustained by DNA distances. Phylogenetic analyses show two major clades. One formed by E. moreni, E. puerulus and E. hirtipes, sharing a high FN and a northern distribution, and THE other formed by E. typus, E. marica and E. morgani with low FN and a central-southern distribution. Two centers of diversification are proposed to explain the evolution of Eligmodontia.     

Contribution to the knowledge of the genus Phyllopodopsyllus T. Scott (Copepoda,Harpacticoida) from Africa with description of two new species

Two new species of marine, sand-dwelling harpacticoids are described: Phyllopodopsyllus pallaresae n. sp. from Namibia, and P. hartmannorum n. sp. from Tanzania. The hitherto unknown male of P. xenus (Kunz) is described from Namibia. Further remarks are made on P. furciger Sars from Tanzania.Zwei neue sandbewohnende Harpacticoiden-Arten werden beschrieben: Phyllopodosyllus pallaresae n. sp. von Namibia und Phyllopodopsyllus hartmannorum n. sp. von Tansania. Außerdem wird das bisher unbekannte Männchen von Phyllopodopsyllus xenus (Kunz) von Namibia beschrieben. Morphologische Merkmale von Phyllopodopsyllus furciger Sars werden anhand eines Fundes von Tansania ergänzt.     

梭菌属分类研究进展:现状和展望

目前构成梭菌属的微生物在系统发育和表型特征上不一致。多相分类数据表明,梭菌属物种之间差异大。大量基于16S rRNA 基因的系统发育研究表明,梭菌属应被限定为梭菌属类群I,作为狭义梭菌属(Clostridium sensu stricto)。尽管有这方面认识,梭菌属新物种仍持续增加,这些新物种并不能与梭菌属类群I 和标准种丁酸梭菌(C. butryicum)形成一致分支,引发梭菌属分类上的混乱。本文明确了梭菌属物种的范围,即只包括模式种和梭菌属类群I。此外,4 个物种念珠状真杆菌(Eubacterium moniliforme)、旋舞真杆菌(Eubacterium tarantellae)、最大八叠球菌(Sarcina maxima)和胃八叠球菌(Sarcina ventriculi)应被调至梭菌属,分别命名为念珠状梭菌(Clostridium moniliforme)、旋舞梭菌(Clostridium tarantellae)、最大梭菌(Clostridium maximum)和胃梭菌(Clostridium ventriculi)。一个新属哈撒韦氏菌属(Hathewaya)被提议成立,3 个梭菌属物种溶组织梭菌(Clostridium histolyticum)、泥渣梭菌(Clostridium limosum)和解朊梭菌(Clostridiumproteolyticum)重新归为溶组织哈撒韦氏菌(Hathewaya histolytica)、泥渣哈撒韦氏菌(Hathewaya limosa)和解朊哈撒韦氏菌(Hathewaya proteolytica),其中Hathewaya histolytica 为模式种。     

The subterranean genus Niphargus (Crustacea, Amphipoda) in the Middle East: A faunistic overview with descriptions of two new species

The Middle East is at the southeastern borderline of the range of the subterranean amphipod Niphargus. The review of new and published data identified two new species and set the guidelines for the future research in the area. The genus in this part of the world seems to be insufficiently studied. The taxonomic status of Niphargus valachicus, population identified as N. spoeckeri and some populations, identified as N. nadarini, need to be reviewed. According to present data, we expect the highest diversity in Western Turkey. The eventual new records of the genus in the Middle East can be expected from those areas where even the longest periods of drought in the recent geological history did not affect the water supply.     

The neuroendocrine system in hibernating mammals: present knowledge and open questions

The present review describes the distribution and the function-dependent reactivity pattern of those peptidergic and aminergic components of the neuroendocrine system of hibernating mammals that have been studied by histological, pharmacological and physiological techniques. Particular attention has been paid to the intrinsic connectivity of the peptidergic apparatus and its input systems. Since the reactivity patterns of the neuroendocrine system show remarkable fluctuations in relation to the various stages of hibernation and euthermia, these fluctuations have been analyzed with respect to (1) their causative role in the regulation of hibernation and (2) their secondary response to physiological changes during hibernation. The author's investigations described in this review have mainly been performed in European hedgehogs (Erinaceus europaeus), European and golden hamsters (Cricetus cricetus, Mesocricetus auratus), dormice (Glis glis), and in Richardson's and Columbian ground squirrels (Spermophilus richardsonii, Spermophilus columbianus), by the use of light- and electron-microscopic immunocytochemistry and histochemistry, in situ hybridization, radioimmunoassays and stereotaxically guided application techniques. These experiments were also performed in hypothermic animals. The (partially published) results obtained by the author and his associates are reviewed with reference to the body of evidence found in the recent literature. With respect to their reactivity patterns, several neuropeptide and transmitter systems can be regarded as candidates for control systems of hibernation. Neuronal complexes immunoreactive for endogenous opiates, in particular enkephalin, and also for vaspressin, somatostatin, substance P, corticotropin-releasing factor and serotonin are probably involved in the neuroendocrine control of hibernation.Dedicated to the memory of Dr. Gesa Merker     

纤毛虫与藻类共生关系的研究现状与展望

纤毛虫与藻类的共生关系在水体环境中广泛存在并有着重要的生态功能。文章回顾了国内外纤毛虫与藻类共生研究的发展历程,主要介绍了纤毛虫与藻类共生的生态功能,以及显微观察与分子生物学技术在纤毛虫与藻类共生研究中的应用;阐述了包括草履虫与小球藻共生关系建立的4个过程及其互作机制、红色中缢虫与隐藻的共生关系、宿主与共生体之间的互作等内容;提出了纤毛虫与藻类共生研究中亟待解决的科学问题,包括草履虫食物泡膜(digestive vacuole, DV)与围藻膜(perialgal vacuole, PV)发挥作用的分子机制、红色中缢虫与隐藻共生关系的建立过程、红色中缢虫在共生过程中的功能作用等,并展望未来的研究方向。     

The current state of korean paleoanthropology

The hominid fossil and Paleolithic archaeology records from the Korean Peninsula are extensive, but relatively little is known about the Korean human evolutionary record outside this region. The Korean paleoanthropological record is reviewed here in light of major research issues, including the hominid fossil record, relative and chronometric dating, lithic analysis, hominid subsistence, and the presence of bone tools, art and symbolism. Some of the major conclusions drawn from this review include: (1) hominid fossils have been found in nine separate sites on the Korean Peninsula; (2) possible Homo erectus fossils are present in North Korea; (3) Ryonggok Cave, in North Korea, has exposed the remains of at least five archaic Homo sapiens individuals; (4) a possible burial of an anatomically modern Homo sapiens child, discovered in Hungsu Cave in South Korea, has been tentatively dated to roughly 40,000 years ago; (5) handaxes and cleavers have been found at a number of sites near Chongokni and they appear to date to at least 100,000 years ago; and (6) taphonomic studies are necessary for addressing issues related to determining the nature of hominid-carnivore interaction over similar resources (e.g. carcasses and shelter); and the presence/absence of Early Paleolithic bone tools, art, and symbolism in Korea.     

Cetobacterium somerae sp. nov. from human feces and emended description of the genus Cetobacterium

Phenorypic and phylogenetic studies were performed on four isolates of an unidentified gram-negative, microaerotolerant, non-spore-forming, rod-shaped bacterium isolated from the feces of children. The unknown organism was bile resistant and produced acetic acid as the major end product of metabolism of peptides and carbohydrates. It possessed a low DNA G + C content of 31 mol %. Comparative 16S rRNA gene sequencing demonstrated that the four isolates were phylogenetically identical (100% 16S rRNA sequence similarity) and represent a hitherto unknown sub-line within the genus Cetobacterium. The novel bacterium displayed approximately 5% sequence divergence with Cetobacterium ceti, and can be readily distinguished from the latter by physiological and biochemical criteria. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown fecal bacterium be classified in the genus Cetobacterium, as Cetobacterium somerae sp. nov. The proposed type strain of Cetobacterium somerae is WAL 14325(T) (ATCC BAA-474(T) = CCUG 46254T).     

The evolution of vocalisations in the genus Corvus: effects of phylogeny, morphology and habitat

In this study we investigated the phylogenetic, morphological and ecological factors affecting the caw calls of 28 species of the genus Corvus, spanning the worldwide range of the taxon. The three phylogeographic groups identified by Goodwin (1986, Crows of the World, British Museum (Natural History), St Edmudsbury Press, Bury St Edmunds), i.e. the American stock, the Palearctic-African stock and the Oriental-Australian stock, were differentiated by some of the acoustic features of their calls, suggesting that historical factors may have played an important role in the evolution of vocalisations in this group. To assess the effects of morphology (body size and bill length) and environment (open vs. closed habitat) and to simultaneously take into account the phylogenetic effects, we used the phylogenetically independent contrast method. This manner of analysis revealed that body size was important in shaping the acoustic attributes of the caw call, as it influenced two temporal and two spectral variables, whereas the effect of bill length was far weaker. Notably, our results did not confirm the negative correlation between call frequency and body size that resulted in a phylogeny-free analysis of the same data in many studies on passerines. Larger Corvus species, in fact, utter calls with higher fundamental frequency than those of smaller species. Hence, these results show that incorporating phylogeny in analyses can substantially alter the conclusions reached by studies carried out with non-phylogenetic approaches. The acoustic environment, considered one of the most important forces driving the evolution of vocalisations in passerines, slightly influenced only two acoustic parameters in the Corvusgenus, call fundamental frequency and duration of pulsed units, both of which increased in the calls of forest species.     

New species in the rheophilous genus Nicsmirnovius Chiambeng & Dumont, 1999 (Branchiopoda: Anomopoda: Chydoridae) and reassignment of Alona eximia Kiser, 1948 and Alonella fitzpatricki Chien, 1970

A morphological comparison of specimens previously assigned to Alona eximia Kiser, 1948 from tropical Africa, Eastern Asia and the Americas shows that this species-group shares a number of morphological characters on the postabdomen, head pores, first antenna and second and fourth limb that separate them from Alona Baird, 1843 but unite them with Nicsmirnovius Chiambeng & Dumont, 1999. Alonella fitzpatricki Chien, 1970, formerly believed to be a junior synonym of A. eximia, is separated from the latter and assigned to the genus Nicsmirnovius. Two new taxa, from Africa and the Island of Socotra (Yemen) are added to the genus. The relationship between the specialised habitat of these chydorids and their morphology is discussed. The geographic range of all known populations is figured and a key to species is presented.     

Revision of the genus <Emphasis Type="Italic">Nuchequula</Emphasis> with descriptions of three new species (Perciformes: Leiognathidae)

The leiognathid genus Nuchequula can be defined by the following combination of characters: mouth protruding downward; a narrow band of small, slender, villiform teeth in both jaws; teeth on upper jaw strongly recurved; the lateral line almost complete; a dark blotch on the nape. Although the genus was first established as a subgenus of Eubleekeria, it is here raised to generic level on the basis of the aforementioned morphological characters and recent molecular biological evidence. The genus comprises six valid species: N. blochii (Valenciennes 1835), distributed in India and Thailand; N. flavaxilla sp. nov., occurring only at Panay I., Philippines; N. gerreoides (Bleeker 1851), widely distributed in the Indo-West Pacific, from the Persian Gulf to Cape York, Australia, and north to Taiwan; N. glenysae sp. nov., from northern Australia and Ambon, Indonesia; N. longicornis sp. nov., from the Gulf of Thailand and Indonesia; and N. nuchalis (Temminck and Schlegel 1845), occurring in southern China including Taiwan, and southern Japan. Diagnostic characters of the species belonging to the genus are as follows: N. blochii—breast scaled, cheek naked, and a conspicuous black blotch distally on spinous dorsal fin; N. flavaxilla sp. nov.—breast naked, dorsolateral body surface fully scaled, preorbital spine bicuspid and not expanded distally, and second dorsal and anal fin spines conspicuously elongated; N. gerreoides—breast naked, anterior part of dorsolateral surface of body almost completely scaled, and second dorsal and anal fin spines not conspicuously elongated; N. glenysae sp. nov.—breast completely scaled, cheek scaled, and unique complicated sensory canals present on the suborbital area, extending to the nape; N. longicornis sp. nov.—breast naked, dorsolateral body surface fully scaled, preorbital spine bicuspid or tricuspid and extended distally, and second dorsal fin spines only conspicuously elongated; N. nuchalis—breast naked, anterior part of dorsolateral surface of body widely naked, and a conspicuous dark blotch distally on spinous dorsal fin.     

The phylogeny of the genus Ischioscia Verhoeff, 1928, with redescriptions of three species (Crustacea: Isopoda: Oniscidea)

The genus Ischioscia Verhoeff, 1928 is reviewed. 26 species are considered valid. A key for their identification is given, as well as a map showing the geographic distribution. The known range of the genus covers a large area from the central Amazon region to the mountains of Guatemala. The species of Ischioscia have a typical “philosciid” habitus (“runner” type); they can be distinguished from other Neotropical species with similar habitus by the following apomorphies: (1) male pereiopod 1 carpus enlarged to a plate-like extension, (2) scale field on male pereiopod 1 covering entire frontal side of the carpus, (3) male pereiopod 7 ischium with a ventral scale field, (4) dactylus in both sexes with a long inner claw. The groundpattern of Ischioscia is reconstructed, and an analysis of the phylogenetic relations within the genus is made on the basis of morphological data. The species are very similar to each other, most differences are found in the male structures of sexually dimorphic features. Ischioscia sturmi (Vandel, 1972), I. amazonica Lemos de Castro, 1955 and I. bolivari Vandel, 1968 are redescribed in detail.     

Two new species of Mesocyclops from southern China and notes on the genus Mesocyclops in China

Two new Mesocyclops species, M. mariae n. sp. and M. shenzhenensisn. sp., are described from southern China, the former species from Guangxi province, the latter from Guangdong province. Both species have setules on the medial margin of the caudal rami. Compared with each other, there are some conspicuous differences, such as the spinule pattern of the antenna basipodite, the structure of receptaculum seminis, the armature of coxopodite and basipodite of P4 and the armature of the caudal rami. The paper also compares the two new species with their supposedly closest relatives, M. pseudospinosus Dussart & Fernando, 1988, M. leuckarti(Claus, 1857) and M. pehpeiensisHu, 1943. In addition, other species of Mesocyclops in China are discussed and a key to 10 Chinese species of Mesocyclops is provided.     

Corylomyces: a new genus of Sordariales from plant debris in France

The new genus Corylomyces, isolated from the surface of a hazelnut (Corylus avellana) in the French Pyrenees, is described, illustrated and compared with morphologically similar taxa. It is characterised by tomentose, ostiolate ascomata possessing long necks composed of erect to sinuose hairs, and one- or two-celled, opaque, lunate to reniform ascospores. Analyses of the SSU and LSU fragments rDNA gene sequences support its placement in the Lasiosphaeriaceae (Sordariales).     

Molecular phylogenetics and taxonomy of the African mole-rats, genus Cryptomys and the new genus Coetomys Gray, 1864

Cryptomys represents the most speciose and widely distributed genus of the Bathyergidae (Mammalia; Rodentia), a family of mole-rats endemic to sub-Saharan Africa. Throughout its range in southern, central, and western Africa, Cryptomys displays diversity in terms of morphology, patterns of behavior, and chromosome number, thus complicating the systematics of the group. A molecular phylogeny was obtained by separate and combined analyses of the mitochondrial 12S rRNA and intron I of the nuclear transthyretin gene for chromosomally and geographically diverse populations of Cryptomys. Our results show that Cryptomys sensu lato is comprised of two distinct and divergent monophyletic clades: hottentotus and mechowi. Based on our analyses, we propose the elevation of the mechowi clade to the genus Coetomys, retaining Cryptomys as the generic epithet of the South African hottentotus clade. This is supported by: (1) reciprocal monophyly of the two lineages based on independent datasets, (2) the level of sequence divergence observed between these lineages relative to other genera (i.e., Bathyergus and Georychus), and (3) different patterns of chromosomal evolution, with Cryptomys sensu stricto being karyotypically conserved (2N=54) and Coetomys exhibiting high karyotypic diversity (2N=40-78).     

The genus Polyarthra in Lake Peipsi

In Lake Peipsi (Estonia) Polyarthra species often dominate the rotifer community, and are represented by 6 species: Polyarthra dolichoptera Idelson, P. longiremis Carlin, P. luminosa Kutikova, P. major Burckhardt, P. remata Skorikov, P. vulgaris Carlin. The highest diversity occurs in August–September, with P. remata and P. luminosa most abundant. Morphometric data including measurements of body, fins and various types of eggs are given. The seasonal development of the different species and their life cycles are considered.     

Senecella siberica n. sp. and the position of the genus Senecella in Calanoida classification

Senecella calanoides Juday has been reported from fresh-water lakes of North America, Northern Siberia and inshore brackish waters of Kara and Laptev Seas. Investigation of 11 females and 2 males from the brackish waters of Neelov Bay (Laptev Sea) shows that second species, Senecella siberica sp. n., can be distinguished from S. Calanoides Juday by the greater size, a slightly asymmetrical female genital segment, the 3 external spines on the 3d exopod of 2 to 4th swimming legs and by more longer left endopod digitiform process of the male 5th legs. S. siberica seems to be brackish-water euryhaline species, inhabiting brackish waters with salinity from 1 to 22. The genus belongs to the family Aetideidae and is the only genus with freshwater representatives.