Culturable diversity of heterotrophic bacteria in Forlidas Pond (Pensacola Mountains) and Lundström Lake (Shackleton Range), Antarctica

Cultivation techniques were used to study the heterotrophic bacterial diversity in two microbial mat samples originating from the littoral zone of two continental Antarctic lakes (Forlidas Pond and Lundstr?m Lake) in the Dufek Massif (within the Pensacola Mountains group of the Transantarctic Mountains) and Shackleton Range, respectively. Nearly 800 isolates were picked after incubation on several growth media at different temperatures. They were grouped using a whole-genome fingerprinting technique, repetitive element palindromic PCR and partial 16S rRNA gene sequencing. Phylogenetic analysis of the complete 16S rRNA gene sequences of 82 representatives showed that the isolates belonged to four major phylogenetic groups: Actinobacteria, Bacteroidetes, Proteobacteria and Firmicutes. A relatively large difference between the samples was apparent. Forlidas Pond is a completely frozen water body underlain by hypersaline brine, with summer thaw forming a slightly saline littoral moat. This was reflected in the bacterial diversity with a dominance of isolates belonging to Firmicutes, whereas isolates from the freshwater Lundstr?m Lake revealed a dominance of Actinobacteria. A total of 42 different genera were recovered, including first records from Antarctica for Albidiferax, Bosea, Curvibacter, Luteimonas, Ornithinibacillus, Pseudoxanthomonas, Sphingopyxis and Spirosoma. Additionally, a considerable number of potential new species and new genera were recovered distributed over different phylogenetic groups. For several species where previously only the type strain was available in cultivation, we report additional strains. Comparison with public databases showed that overall, 72% of the phylotypes are cosmopolitan whereas 23% are currently only known from Antarctica. However, for the Bacteroidetes, the majority of the phylotypes recovered are at present known only from Antarctica and many of these represent previously unknown species.     

The mesonephric (wolffian) and paramesonephric (müllerian) ducts of golden hamsters express different intermediate-filament proteins during development

We analysed the expression of intermediate-filament proteins in the developing mesonephric duct (the precursor of the male genital ducts) and the paramesonephric duct (the precursor of the female genital ducts) of golden-hamster embryos using immunohistochemical methods. Embryos were investigated from the early stages of duct development, i.e. at 9.5 days post conceptionem (dpc), through sexual differentiation, until birth (15.5 dpc). Monospecific antibodies to vimentin or keratins 7, 8, 18 or 19 as well as two keratin antibodies that are pan-epithelial in human tissues were tested. Both ducts expressed vimentin to some degree from their early stages (mesonephric duct from 9.5 dpc onwards; paramesonephric duct from 10.5 dpc onwards) until birth. No keratins were detectable at these earliest stages. In the mesonephric duct, keratins 7, 18 and 19 appeared simultaneously at 10.5 dpc and persisted until birth. In the paramesonephric duct, only keratin 18 was detectable at first (at 12.0 dpc), with the expression of keratins 7 and 19 being delayed until 14.5 dpc. This feature was irrespective of sexual differentiation, which begins at 11.0 dpc, so that, in males, these keratins appeared on cue, even though the paramesonephric duct was regressing at this time. The expression of keratin 8 could not be demonstrated in either duct using the antibodies tested in our study. By 14.5 dpc, the differentiated male mesonephric duct and the differentiated female paramesonephric duct exhibited the same intermediate-filament protein pattern (weak vimentin expression and strong expression of keratins 7, 18 and 19), in spite of differences in the intermediate-filament protein patterns exhibited by the two ducts during early development. These different programmes of intermediate-filament protein regulation do not support the concept that the mesonephric duct makes a cellular contribution to the paramesonephric duct during the development of the latter.     

Rhinanthus serotinus (Schönheit) Oborny (Scrophulariaceae): immunohistochemical and ultrastructural studies of endosperm chalazal haustorium development

Chalazal endosperm haustorium in Rhinanthus serotinus consists of a single large binucleate cell. It originates from the primary endosperm cell dividing transversely into two unequal cells: a smaller micropylar cell and a larger chalazal cell. The chalazal cell undergoes a single mitotic division, then lengthens significantly during development and functions as a chalazal endosperm haustorium. In this paper, immunofluorescent techniques, rhodamine phalloidin assay, and electron microscopy were used to examine the actin and tubulin cytoskeleton during the development of the chalazal haustorium. During the differentiation stage, numerous longitudinally oriented bundles of microfilaments ran along the axis of transvacuolar strands in haustorium. Microtubules formed intensely fluorescent areas near the nuclear envelope and also formed radial perinuclear microtubule arrays. In the fully differentiated haustorium cell, the actin cytoskeleton formed dense clusters of microfilaments on the chalazal and micropylar poles of the haustorium. Numerous microfilament bundles occurred near wall ingrowths on the chalazal wall. There were numerous clusters of microfilaments and microtubules around the huge lobed polytenic haustorial nuclei. The microfilaments were oriented longitudinally to the long axis of the haustorium cell and surrounded both nuclei. The microtubules formed radial perinuclear systems which were appeared to radiate from the surface of the nuclear envelope. The early stage of degeneration of the chalazal haustorium was accompanied by the degradation of microtubules and disruption of the parallel orientation of microtubules in the chalazal area of the cell. The degree of vacuolization increased, autophagous vacuoles appeared and the number of vesicles decreased.     

Über die biologie blutsaugender simuliiden (diptera)

Summary Swarming behaviour of the mammalophilic simuliids Wilhelmia equina, W. salopiensis and Boophthora erythrocephala is closely related to sex-finding. Long-range orientation occurs by optically directed swarming of the towards a dark marker above them contrasting with the bright sky. flying directly to the same marker or the bigger object carrying it, e.g. a tree, are visually recognized by the at a short distance (short-range orientation).Sex-orientation shows the following pattern of behaviour: Weather conditions (temperature, relative humidity, covering of the skyfree, partially or covered) may vary to a great extent without obvious effect. If brightness of the sky exceeds 5000 lux and velocity of the wind is limited to 10 m/sec measured 1 m above the ground, and begin to seek for moving (e.g. blood hosts of , adequate dummies) or motionless conspicuous objects (e.g. trees, cottages).Around these objects behaviour differs between species, but more markedly between the sexes: are flying directly to the object and sit down, are swarming in a short distance from it, waiting for the arrival of more . As the emerge from the pupae earlier than the which are not yet inseminated, they are more numerous. Furthermore, a are swarming longer than one day (demonstrated by tagging experiments) so that every may copulate several times.Orientation of towards the optic marker is the last stage in the long-range orientation. With regard to of W. equina, the pattern is as follows: The occupying the uppermost flying position in the whole swarm orientates itself in such a manner that the image of the marker is centrally in the median space of its head, which is covered by both complex eyes having an overlapping space of 38°. Even during individual movements this position is maintained so that the marker leaves this space only partially. Moreover the remains at such a distance that the image of the marker neither exceeds the anatomical field of vision of the dorsal parts of the complex eyes in the sagittal plane (54°) nor disappears from it completely. Accordingly, the vertical distance from the marker depends on its size, but at a maximum distance of 60 cms the fly changes its orientation, using a portion of the marker, such as a corner, as new fixpoint. Orientation to the marker is not restricted to the background of the open sky; other backgrounds of the same colour are accepted, too, if they are smaller than the anatomical field of vision in the median sagittal plane (54°). Furthermore, lateral parts of the same field of vision, which is 158° in the transversal plane, may be covered up to one half of its width by dark objects, whereas no object is tolerated touching the median sagittal field of vision in front. This demonstrates, too, that not visual perception as such, but the special behaviour of the simuliids is related to the anatomical field of vision.With W. salopiensis, W. equina, and B. erythrocephala meeting and recognizing of the partner for copulation usually occurs during flight. Both partners, however, fall down to the ground immediately thereafter and seperate within 3–5 seconds. In the final stage of copulation the partners are in opposite position, but the abdomina remain in normal position, i.e. turned at 180°, the , lying on its back with its abdomen not twisted. Compared with the copulation among Culicidae and Ceratopogonidae, this position must be considered more primitive.The special differentiation of the complex eyes of male simuliids permits them to recognize both distances (as indicated by the orientation to the marker) and moving objects, enabling them to distinguish between flying , which will be pursued, and in the same swarm, the presence of which causes no reaction, and enemies such as hovering flies and preying hymenoptera, the arrival of which produces a flight reaction. All these actions are realized by the coarsely screened dorsal parts of the complex eyes.The anatomical position of the male genitalia must be considered morphologically primitive, as the hypopygium lacks inversion. Transfer of sperms is by means of a spermatophore. In the female, the accessory glands of the 8th segment open into the ductus receptaculi, whereas the glands of the 9th segment open to the outside close to the gonoporus.

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Herrn Oberlehrer i. R. G. Schlörer zum 75. Geburtstag gewidmet.     

Larval development and morphogenesis of the sea spider Pycnogonum litorale (Ström, 1762) and the tagmosis of the body of Pantopoda

Aspects of pantopod ontogeny have been known for a long time, but specific information is available for only a few species. Our account of the postembryonic development of Pycnogonum litorale is based on laboratory-reared individuals and SEM studies. We documented particularly all early developmental stages, with emphasis on morphogenetic changes of head structures and appendages. In P. litorale the protonymphal limbs, the chelicerae and two more uniramous legs, degenerate already during the larval phase; only the third one, the ovigers, reappears in male juveniles. Other Pantopoda vary in this aspect from retention of all three protonymphal appendages to their complete reduction, as in P. litorale. Accordingly, the two post-cheliceral larval appendages are separate legs in front of the walking legs in the adults, the ‘parapalps’ and the ‘ovigers’, but they do not occur in all pantopods. The scarcity of studies of the ontogeny of Pantopoda prevents us from a more conclusive picture, but our data are promising to state that additional such studies will increase the usability of ontogenetic data for a phylogenetic analysis of Pantopoda, the crown group of the Pycnogonida. We also discuss the phylogenetic implications of our data in the light of new information from Hox genes and developmental-biological data on body segmentation and tagmosis of the Chelicerata. These suggest the homology of chelicerae and antenn(ul)ae of other euarthropods. Accepting this, we conclude that the adult pycnogonid/pantopod head, the cephalosoma, corresponds to the euarthropod head and that the protonymph with three appendage-bearing segments may represent an even shorter, possibly phylogenetically older larval type than the euarthropod ‘head larva’ bearing four pairs of appendages. In further consequence, the fourth walking legs of Pycnogonida/Pantopoda should correspond to the first opisthosomal appendages, the chilaria, of euchelicerates. This implies that within Pycnogonida the post-prosomal region became compacted during evolution to a single leg-bearing segment plus a tubular end piece. Accordingly, neither the anterior nor the posterior functional boundaries of the walking-leg region correspond to the original tagma borders.     

Apparatus structure of the Ordovician conodontDecoriconus peselephantis (Lindström 1955)

The Lower Ordovician conodont species first described asScolopodusl peselephantis Lindström 1955, has a seximembrate apparatus of laterally compressed, variously curved and flexed coniform elements. These are very small and invariably striated or multicostate. The taxon is reassigned toDecoriconus Cooper 1975, a genus hitherto known by species from Upper Ordovician and Silurian strata. These younger species share several characteristic morphological features with the older species investigated in this work. When studied in detail, it was discovered thatD. peselephantis was the first species in a lineage which also included two successive new species. Of these,D. mercurius n. sp. occurs in the middle Arenig, whileD. pesequus n. sp. ranges from the late middle Arenig and at least through the Llanvirn, possibly even into the Caradoc. These new species, which were previously included intoS.? peselephantis, are described and their geographic distribution investigated. In addition, a probable homeomorphic form ofD. peselephantis, Toxotodus? gabriellae n. sp., is diagnosed.     

Description of immature stages of Agelanius cortesi (González) from central Chile (Diptera: Tabanidae)

The immature stages of Agelanius cortesi are described and illustrated from immatures collected in Quebrada Los Almendros, Río Clarillo National Reserve, Cordillera Province, central Chile, and reared in the laboratory. Larvae of A. cortesi were found below the soil surface associated with other invertebrates.

Resumen

Se describe e ilustra los estados inmaduros de Agelanius cortesi colectados en la Quebrada Los Almendros, Reserva Nacional Río Clarillo, Provincia Cordillera de Chile central, los cuales fueron criados en el laboratorio. Las larvas de A. cortesi fueron encontradas bajo la superficie del suelo asociadas con otros invertebrados.     

The life history,production and food habits of Pontoporeia affinis Lindström (Crustacea: Amphipoda) in mesotrophic Lake Erken

The life history and feeding habits of Pontoporeia affinis Lindström were studied in mesotrophic Lake Erken during 1982 to 1983. The greatest densities and biomasses of P. affinis occurred at 12 m (662 ind./m² and 118.2 mg dw/m², respectively) with values decreasing at the shallower and deeper regions. The life cycle of Pontoporeia was one year, with recruitment occurring in April, at which time the majority of the population consisted of individuals <2 mm. Overall the gut content of Pontoporeia was predominantly composed of detritus (97.6%) with algae accounting for 2.3%. Annual production was highest at 12 m (386.2 mg dw/m²) and lowest at 16 m (8.1). The highest production occurred during September, coinciding with the autumn Bacillariophyceae bloom.     

The hypotensive effect of intrathecally injected (m)VD-hemopressin(α) in urethane-anesthetized rats

Previous studies suggest that cannabinoids system plays an important role in cardiovascular regulation. (m)VD-hemopressin(α) (VD-Hpα), an 11-residue peptide originating from the α₁ chain of hemoglobin, was recently reported as a selective agonist of cannabinoid CB₁ receptor. The present study was undertaken to investigate the intrathecal (i.t.) action of (m)VD-Hpα on blood pressure in urethane-anesthetized rats. Our results demonstrated that injections of (m)VD-Hpα (5–30 nmol, i.t.) produced a dose-dependent decrease in mean arterial pressure (MAP), similar to that of the non-peptidic cannabinoid receptor agonist WIN55212-2 (1.25–10 nmol, i.t.). The hypotensive effect of (m)VD-Hpα was not influenced by the CB₁ receptor antagonist AM251 (20 nmol, i.t.) or the CB₂ receptor antagonist AM630 (20 nmol, i.t.). However, WIN55212-2-induced hypotension was almost completely prevented by i.t. administration of AM251, not by AM630. The spinal hypotension of (m)VD-Hpα and WIN55212-2 was significantly reduced by pretreatment with the α-adrenoceptor antagonist phentolamine (1 mg/kg, i.v.), but not by the β-adrenoceptor antagonist propranolol (2 mg/kg, i.v.) or the muscarinic receptor antagonist atropine (2 mg/kg, i.v.). In addition, l-NAME (50 mg/kg, i.v.), the inhibitor of nitric oxide (NO) synthase, significantly reduced WIN55212-2-induced hypotension, but had no effect on the hypotensive response to (m)VD-Hpα. Collectively, the results show that i.t. administration of (m)VD-Hpα induces a decrease in MAP via a non-CB₁ and non-CB₂ mechanism.     

The post-embryonic development of Remipedia (Crustacea)—additional results and new insights

The post-embryonic development of a species of the enigmatic crustacean group Remipedia is described in detail for the first time under various aspects. Applying a molecular approach, we can clearly prove the species identity of the larvae as belonging to Pleomothra apletocheles. We document the cellular level of several larval stages and the differentiation of segments, limbs, and the general body morphology applying the techniques of confocal laser scanning microscopy and scanning electron microscopy. In addition, we document the swimming behavior and the peculiar movements of the naupliar appendages. A comparison of our results with published data on other Crustacea and their larval development tentatively supports ideas about phylogenetic affinities of the Remipedia to the Malacostraca. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. An erratum to this article can be found at     

An electron microscope study of spermiogenesis in Spirorbis (Laeospira) mörchi Levinsen (Polychaeta)

Summary 1. In the hermaphroditic polychaete Spirorbis (Laeospira) mörchi, early spermatids develop in clusters within the coelom of the male segments. The cells within a single cluster are all in the same stage of development and are connected by an extensive cytoplasmic bridge system. 2. The acrosome forms in a single lamella of the Golgi apparatus which bears a close association to the plasma membrane. The final position of the acrosome is at a point considerably removed from the site of formation. 3. The nuclear changes culminating in condensation and elongation of the head are described. A rearrangement of cytoplasmic microtubules occurs simultaneously with nuclear elongation. 4. Redundant nuclear envelope, resulting from nuclear volume reduction, is pinched off in the form of four vesicles. The latter structures are lost with the residual cytoplasm. 5. Pour spherical mitochondria elongate to become incorporated into the middle-piece. A rearrangement of microtubules also occurs simultaneously with mitochondrial elongation. Cytoplasmic microtubules are absent from the fully formed sperm.This investigation was made possible through a Postdoctoral Fellowship from the National Science Foundation, 44150. — I wish to express my gratitude to Dr. John Luft for the training I received in the techniques of electron microscopy. Dr. James Koehler and Dr. Daniel Szollosi are thanked for their many helpful suggestions.     

The abundance and diversity of gut bacteria of rice leaffolder Cnaphalocrocis medinalis (Guenée) across life stages

The bacterial community living in the insect gut may play an important role in nutrition, immunity and protection, detoxification of toxins, and inter- and intra-specific communication. Rice leaffolder Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Crambidae) is a notorious pest in rice, and the diversity of the gut bacteria of C. medinalis across life stages are not well understood. Here, the diversity and abundance of the gut bacterial community in C. medinalis through life stages were investigated using Illumina Miseq technology. A total of 22 bacterial phyla, 42 classes, 100 orders, 179 families, 350 genera and 395 species were identified across the different life stages of C. medinalis. Proteobacteria and Firmicutes phyla were the dominant bacterial taxa. Members of the genera Enterococcus, unclassified Enterobacteriaceae, Wolbachia, Acinetobacter, Stenotrophomonas, Microbacterium, Bacillus, Corynebacterium, Lampropedia, and Sphingobacterium were found at all life stages. Enterococcus and unclassified Enterobacteriaceae occupied higher relative abundance among bacteria community in the 2nd to 5th instar larvae, pupae and adults. The structure of bacterial community differed across the life stages of C. medinalis. Our findings will enrich the understanding of gut bacteria in C. medinalis, and will provide foundation and assistance for the development of novel pest management strategies through utilization of microbiota.     

Beobachtungen zur Lebensweise von Pycnogonum litorale (Ström) (Pantopoda)

Zusammenfassung Am Leitdamm des Jadebusens lebt Pycnogonum litorale im Lückensystem des Miesmuschelbesatzes. Dieser bietet mit hartem Untergrund, hoher Feuchtigkeit bei Niedrigwasser, genügend Actinien als Nahrung und guter Durchströmung bei gleichzeitigem Schutz vor Vertragung—offensichtlich günstige Lebensbedingungen für Pycnogonum litorale.Der Eiablage im Februar geht eine Reiterstellung des Männchens auf dem Weibchen von durchschnittlich 24 Tagen voraus. Unter künstlichen Kurztagbedingungen kann diese Reiterstellung auch außerhalb der Fortpflanzungsperiode eingenommen werden. Die Eier werden durch Rumpfbewegungen beider Partner zu den Ovigeren des Männchens bewegt. Bei 12°C schlüpfen die Larven etwa 41 bis 46 Tage nach der Eiablage aus, bei 19°C, im Sommer, schlüpften keine Larven.Im Jadebusen leben die Larven etwa 1/2 Jahn endoparasitisch in Hydrozoen. Die an die Metamorphose anschließende juvenile Phase, in der die Tiere frei leben, dauert ein knappes Jahr, die Reifehäutung erfolgt normalerweise im Sommer des zweiten Jahres, die Fortpflanzungsperiode etwa 6 Monate später, im Winter.

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Observations on the life biology of Pycnogonum litorale (Ström) (Pantopoda)

Summary Pycnogonum litorale lives in an interstitial system, of the mussel zone on the embankment of the Jadebusen. Hard substrate, high humidity at low tide, sufficient Metridium senile as food, and active currents together with protection from drifting, constitute favourable conditions for this pycnogonid.Prior to laying egg in February, the male remains in a riding position upon the female for approximately 24 days. Under artificial short-day conditions the riding position may also be assumed outside of the reproductive period. The eggs are transported to the ovigers of the male by trunk movements of both partners. At 12°C the larvae hatch about 41–46 days after egg-laying. No larvae hatched from eggs laid during summer at 19°C.The larvae live endoparasitically in Hydrozoa for about 1/2 year. Following metamorphosis, the freeliving juvenile phase lasts barely a year. The maturation moult normally takes place in the summer of the second year, the reproductive period beginning about 6 months later, in winter.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Interactions ofMonoporeia affinis (Lindström) (Amphipoda) with sedentary Chironomidae

Interannual population oscillations ofMonoporeia affinis and sedentary chironomids are negatively correlated in Lake Mälaren. Sedentary chironomid abundance regressed againstM. affinis density was highly significant at a lag response of one year (adj. R²=0.54, P=0.0001). The inverse correlation between Tanytarsini (Micropsectra sp. andTanytarsus sp.) andM. affinis densities supports a recruitment limitation hypothesis,viz. that the growth or survival of early instar chironomids is low at high amphipod densities. Microcosm studies showed density-dependent effects on the growth and survival of second instarCh. riparius larvae across an amphipod density gradient. No significant effects were found on growth or survival of third instars. These findings support the chironomid recruitment limitation hypothesis. Amphipod predation on early instar chironomid larvae is suggested as a population controlling mechanism.