Two new species of gorgonian octocorals from the Tropical Eastern Pacific Biogeographic Region (Cnidaria,Anthozoa, Gorgoniidae)

The gorgoniid Eugorgia is exclusively an eastern Pacific genus. It has a wide geographic and bathymetric range of distribution, found from California to Perú and extends down to 65 m deep. Two new species are herein described. The morphological characters were analyzed and illustrated by light and scanning electron microscopy. Eugorgia beebei sp. n. can be distinguished by its white, ascending, sparse colony growth. Eugorgia mutabilis sp. n. can be distinguished by its white colony that changes color after collection, and the conspicuous sharp-crested disc sclerites. From a morphological point of view the new species are related to the daniana-group, the rubens-group and the siedenburgae-group of Eugorgia; their affiliations, and the proposal of a new group are discussed. These new species increases the number of species in the genus to 15, and contribute to the knowledge of the eastern Pacific octocoral biodiversity.     

The role of environmental sodium chloride relative to calcium in gill morphology of freshwater salmonid fish

Summary Ultrastructure, distribution and abundance of cell types were examined in the gills of two freshwater salmonid species, Salmo fario and Salmo gairdneri, in media of selected ion content. In plain hard water (PW) with high concentrations of Ca²⁺, Na⁺, and Cl^-, gill chloride cells (CC) were confined to trailing edges and interlamellar regions of filaments whereas in mountain soft water (MW) with low concentrations of Ca²⁺, Na⁺, and Cl^-, CC were more numerous on filaments and covered lamellae, particularly along trailing edges. CC also appeared on lamellae of PW trout acclimated to soft water in a pond. This proliferation was not alleviated when ambient Ca²⁺ levels were raised (MW + Ca²⁺) but regressed in elevated NaCl media (MW + NaCl). The regression process involved an initial covering of CC by pavement cells followed by cytolysis and then eventual disappearance of CC. In MW, mucous cells were distributed mainly on trailing edges and, to a lesser extent, leading edges of filaments; they were absent from lamellae regardless of external ion levels.The results of this study shed some light on the functional significance of CC in freshwater fish. It is suggested that proliferation of CC is an adaptive response to dilute freshwater (i.e. [NaCl]<0.1 mequiv·1^-1).     

噬菌蛭弧菌简易保存方法的研究

本文报道了噬菌蛭弧菌在自来水宿主软琼脂中,于4℃环境(冰箱)存活的时间.发现噬菌蛭弧菌在自来水宿主软琼脂中,于4℃冰箱中保存,至少可以存活3个月以上,一般为5～8个月左右,最长时间可达18个月。但在自来水宿主双层琼脂平板上形成的噬斑数目,随着保存时间的延长,则有不同程度的减少。     

Hyolith guts in the Cambrian of northern Australia -turning hyolithomorphs upside down

A single specimen of the early Middle Cambrian (Ordian) orthothecimorph hyolith Gudugu-wan hardmani with preserved gut filling has been discovered in the Montejinni Limestone, Wiso Basin, northern Australia. This represents only the eighth such occurrence worldwide. The specimen is unique among orthothecimorphs in retaining the gut filling in combination with the external mould of the operculum and invites revision of the accepted soft-part recon struction in this group, whereby the opercular lateral processes are now recognized to be ventral. Thus orthothecimorph conchs, if horizontal in life, would have been oriented ventral side down, while hyolithomorphs adopted the reverse orientation: horizontal, ventral side up.     

Deep soil heterogeneity and fine root distribution in forests and pastures of eastern Amazonia

Little is known about deep soil heterogeneity, or its relationship with fine root distribution. Beneath a mature, closed-canopy forest of eastern Amazonia, and the pastures and secondary forests that are derived from this forest, soil soft spots and hollow chambers occur to at least 9 meters depth. We measured the vertical distribution of these soil patches, and compared chemical characteristics, mycorrhizal infection, and root density of soil soft spots with the surrounding matrix of more homogeneous soil. Soil soft spots and chambers varied little with depth, but occupied the greatest soil volume (0.8 to 1.2%) from 4 to 6 m depth in the mature forest. Soft spots had lower pH, P availability and arbuscular mycorrhizal infection, and higher K availability than surrounding soil. Root length density was 2 to 15 times higher in soft spots than in surrounding soil. In the pastures, roots were found only in soil soft spots at depths of >3 m. Pastures and secondary forest had more soil chambers in the upper meter of soil than mature forest, but were otherwise indistinguishable in their patterns of deep soil heterogeneity. Soil soft spots may be vestiges of cutter ant nest chambers, while hollow chambers are cutter ant chambers and root channels. Chambers may act as conduits for root penetration and water penetration to deep soil.Abbreviations AM arbuscular mycorrhizae - RLD root length density (root length per unit of soil volume)     

Embryonic and larval development of brown trout, Salmo trutta L.: exposure to trace metal mixtures in soft water

Freshly fertilized ova of brown trout, Salmo trutta L., were exposed to all possible mixtures of Al (6000 nmol 1¹), Cu (80 nmol 1⁻¹), Pb (50 nmol 1⁻¹) and Zn (300 nmol 1 ¹). In a separate experiment, newly hatched brown trout yolk-sac fry were exposed to Mn (1500 nmol 1⁻¹), Fe (2500 nmol 1 ¹), Ni (200 nmol 1⁻¹) or Cd (4 nmol 1 ¹), separately, and in mixtures with either Al or Cu. Both experiments were conducted in flowing, artificial softwater media nominally at pH 5.6 [Ca] 20 μmol 1 ¹ and 10° C.
Mortalities were high in fry subjected to treatments which contained both Al and Cu (31–72%), and to the Cu + Fe treatment (78%) compared with those from the other trace metal mixtures (0–22%). In all the treatments tested, fry exposed to trace metal mixtures containing Al and/or Cu had reduced whole body Ca, Na and K content, and seriously impaired skeletal calcification. Whole body Mg content was variable. In trace metal mixtures which contained Cu but not Al, the effects on fry survival and whole body mineral content were in general more deleterious than the corresponding mixtures but with Al present rather than Cu. The presence of Pb and/or Zn in mixtures with Al and/or Cu had a slight ameliorative effect in terms both of fry survival and whole body mineral content.     

Maintenance of two genetic entities by habitat selection

Summary In the laboratory, the two species of copepodsLepeophtheirus thompsoni andLepeophtheirus europaensis, ectoparasites of flatfishes, can meet and mate on at least one host species. In the wild however, these two species are found isolated on their sympatric hosts. Habitat selection theoretically represents a powerful enough mechanism to explain the maintenance of genetic heterogeneity in the wide sense. In this paper, the host colonization process is studied for both parasite species. It is shown that each parasite can develop and reach adult age on each host species. However,L. thompsoni is highly selective; it almost totally refuses to colonize hosts other than its natural one.Lepeophtheirus europaensis, on the contrary, readily infests turbot and brill in single-host experiments, but strongly prefers the brill when it has a choice. It appears that these two genetic entities are sympatrically maintained due to strong habitat selection. Such a pattern could theoretically only occur in a soft-selection context (density dependence). This point is discussed with respect to the different patterns in host use found in the geographical distribution of these parasites.     

Theoretical Study of the TiO2 and MgO Surface Acidity and the Adsorption of Acids and Bases

We present ab-initio periodic Hartree–Fock calculations (crystal program) of small molecules on TiO₂ and MgO. The adsorption of the molecules may be molecular or dissociative. This depends on their acid and basic properties in the gas phase. For the molecular adsorption, the molecules are adsorbed as bases on Ti(+IV) sites, the adsorption energies correlate with the proton affinities. The dissociations on the surface correlate with the gas phase cleavages: thus, the dissociation of MeOH leads to a preferential basic cleavage (the fragment HO– is adsorbed on a Ti⁺⁴ ion and the fragment Me⁺ is adsorbed on a O²– ion of the oxide). The opposite result is obtained with MeSH. Another important factor is the adsorbate–adsorbate interaction: favorable cases are a sequence of H-bonds for the hydroxyl groups resulting from the water dissociation and the mode of adsorption for the ammonium ions. Lateral interactions also force the adsorbed CO₂ molecules to bend over the surface so that their mutual orientation resembles the geometry of the CO₂ dimer. With respect to water adsorption, MgO appears to be a basic oxide. As experimentally observed, NH₃ adsorbs preferentially on TiO₂ and CO₂ on MgO. However, this difference of reactivity should not be expressed in terms of acid vs. basic behaviour but in terms of hard and soft acidity. The MgO surface is a 'soft' acidic surface that reacts preferentially with the soft base, CO₂.     

Fine needle aspiration (FNA) in the diagnosis of soft tissue tumours; a review of 22 years experience

FNA plays an important role in preoperative diagnosis of soft tissue tumours. A close clinical/morphologic cooperation is essential. FNA should be performed on the most accessible part of the tumour, avoiding penetration of the deep portions of the tumour. Needles 0.7 mm (22 G) are recommended. For deep lesions, needles with a stylet should be used. After the FNA, tattooing of the aspiration channel is recommended, and the channel is surgically removed together with the tumour, if a sarcoma. Material from the FNA can be used for additional examinations, i.e. electron microscopy, immunohistochemistry, DNA ploidy analysis and chromosomal analysis. Those techniques are of great importance in the differential diagnosis, particularly in the paediatric small/round cell tumours. the majority of sarcomas can be defined as low grade or high grade malignant in FNA. For malignancy grading the following parameters are used: cellularity, pleomorphism, chromatin pattern, nucleolar structure, mitotic figures and necroses. Cytodiagnostic details of the most common soft tissue tumours and their differential diagnoses are presented.