Redescription of Pseudoaugeneriella nigra (Langerhans, 1880), new combination (Polychaeta, Sabellidae), with remarks on some characters of Fabriciinae

The fabriciin sabellid species, Fabricia nigra Langerhans, 1880 from the Macaronesian region, is assigned to the genus Pseudoaugeneriella Fitzhugh, 1998, based on information provided by newly collected specimens. The species is redescribed, including the variability of key characters. Moreover, structures of the anterior end — dorsal lips, ventral filamentous appendages, peristomial rings — of Pseudoaugeneriella nigra and other species of Fabriciinae are studied histologically and by means of SEM. The systematic significance of these characters in Fabriciinae is discussed.     

家兔脊神经节内肥大细胞与肽能神经关系的观察

探讨脊神经节内肥大细胞与肽能神经的关系,采用常规组织学染色和免疫组织化学方法对家兔脊神经节内肥大细胞和P物质免疫阳性反应进行观察。结果显示：在P物质免疫反应阳性的神经元和神经纤维周围散在着肥大细胞,表明,脊神经节内,肥大细胞与肽能神经存在着组织形态学上的构筑关系。     

Spine development in Brachionus quadridentatus from an Australian billabong: genetic variation and induction by Asplanchna

Fertilized resting eggs of Australian Brachionus quadridentatus hatched 2–3 days after hydration into females with or, more frequently, without posterior lateral spines. These females then produced clones with short-spined or long-spined phenotypes. Asplanchna girodi induced females from two short-spined clones and one long-spined clone to produce daughters with significantly longer posterior lateral spines. In all clones, there were significant differences in spine development among offspring of mothers within Asplanchna and control treatments. The range of phenotypes reported in one short-spined clone is observed in the billabong and includes much of the variation described for the species, with mehleni (long-spined) phenotypes occurring with Asplanchna. In B. quadridentatus, the ecological significance of long-spined, basic phenotypes, and of the spine-development response to Asplanchna, is unclear. In laboratory cultures, females of all clones were attached to the substratum or water surface, and were safe from Asplanchna; in nature, females are epiphytic and probably rarely susceptible to Asplanchna. Most (96%) resting eggs produced in cultures and kept under culture conditions hatched after a 7-day latent period. This raises questions regarding natural conditions which might prevent hatching and allow accumulation of resting eggs in a sediment egg bank. Hatching of resting eggs in nature may be enhanced in sediments which dry and then become flooded after rains.     

Two Reproductive Life History Types of Kokanee, Onchorynchus nerka, Exhibit Multivariate Morphometric and Protein Genetic Differentiation

Two reproductive types of kokanee are found in Okanagan Lake, British Columbia: one form that spawns in streams, and another that spawns approximately 2–4 weeks later along beaches of the lake. We examined the levels and patterns of genetic and morphometric variation among three populations (1 beach and 2 stream populations) to better understand life history differentiation. We assayed allozyme variation at 74 loci and identified 15 P_0.095 loci. Average F_ST was 0.041 among the three samples; the two stream-spawning populations grouped together in genetic distance analyses. We examined multivariate morphometric variation and fin size/shape variation using 35 truss characters. Populations did not sort morphologically by spawning type in principal component and relative warp analyses. Instead both analyses indicated that one stream-spawning population (Peachland Creek) was significantly more robust and had shallower caudal fins in comparison to the other samples. Second, clear multivariate shape differences between males and females were identified involving jaw size, mid-body dimensions, and caudal fin shape. A simple bivariate plot of tail `forkness' against fork length demonstrated that males had more forked tails and females had flattened tails. Level of differentiation of secondary sexual characteristics did not vary between the spawning types, although the beach-spawning population and one stream-spawning population did not show the strong, gender-discriminating variability in tail forkness. Although these two reproductive life history types of kokanee form discrete genetic groups, environmental differences are apparently insufficient to effect consistent differences in body shape, or fin size and shape between stream and beach-spawning morphs.     

The relationships between stocking density and welfare in farmed rainbow trout

There is increasing public, governmental and commercial interest in the welfare of intensively farmed fish and stocking density has been highlighted as an area of particular concern. Here we draw scientific attention and debate to this emerging research field by reviewing the evidence for effects of density on rainbow trout. Although no explicit reference to ‘welfare’ has been made, there are 43 studies which have examined the effects of density on production and physiological parameters of rainbow trout. Increasing stocking density does not appear to cause prolonged crowding stress in rainbow trout. However, commonly reported effects of increasing density are reductions in food conversion efficiency, nutritional condition and growth, and an increase in fin erosion. Such changes are indicative of a reduced welfare status—although the magnitude of the effects has tended to be dependent upon study‐specific conditions. Systematic observations on large scale commercial farms are therefore required, rather than extrapolation of these mainly small‐scale experimental findings. There is dispute as to the cause of the observed effects of increasing density, with water quality deterioration and/or an increase in aggressive behaviour being variously proposed. Both causes can theoretically generate the observed effects of increasing density, and the relative contribution of the two causes may depend upon the specific conditions. However, documentation of the relationship between density and the effects of aggressive behaviour at relevant commercial densities is lacking. Consequently only inferential evidence exists that aggressive behaviour generates the observed effects of increasing density, whereas there is direct experimental evidence that water quality degradation is responsible. Nevertheless, there are contradictory recommendations in the literature for key water quality parameters to ensure adequate welfare status. The potential for welfare to be detrimentally affected by non‐aggressive behavioural interactions (abrasion, collision, obstruction) and low densities (due to excessive aggressive behaviour and a poor feeding response) have been largely overlooked. Legislation directly limiting stocking density is likely to be unworkable, and a more practical option might be to prescribe acceptable levels of water quality, health, nutritional condition and behavioural indicators.     

Fin whale (Balaenoptera physalus) population identity in the western Mediterranean Sea

Archival bottom‐mounted audio recorders were deployed in nine different areas of the western Mediterranean Sea, Strait of Gibraltar, and adjacent North Atlantic waters during 2006–2009 to study fin whale (Balaenoptera physalus) seasonal presence and population structure. Analysis of 29,822 recording hours revealed typical long, patterned sequences of 20 Hz notes (here called “song”), back‐beats, 135–140 Hz notes, and downsweeps. Acoustic parameters (internote interval, note duration, frequency range, center and peak frequencies) were statistically compared among songs and song notes recorded in all areas. Fin whale singers producing songs attributable to the northeastern North Atlantic subpopulation were detected crossing the Strait of Gibraltar and wintering in the southwestern Mediterranean Sea (Alboran basin), while songs attributed to the Mediterranean were detected in the northwest Mediterranean basin. These results suggest that the northeastern North Atlantic fin whale distribution extends into the southwest Mediterranean basin, and spatial and temporal overlap may exist between this subpopulation and the Mediterranean subpopulation. This new interpretation of the fin whale population structure in the western Mediterranean Sea has important ecological and conservation implications. The conventionally accepted distribution ranges of northeastern North Atlantic and Mediterranean fin whale subpopulations should be reconsidered in light of the results from this study.     

In vivo Electroporation of Morpholinos into the Regenerating Adult Zebrafish Tail Fin

Certain species of urodeles and teleost fish can regenerate their tissues. Zebrafish have become a widely used model to study the spontaneous regeneration of adult tissues, such as the heart¹, retina², spinal cord³, optic nerve⁴, sensory hair cells⁵, and fins⁶.The zebrafish fin is a relatively simple appendage that is easily manipulated to study multiple stages in epimorphic regeneration. Classically, fin regeneration was characterized by three distinct stages: wound healing, blastema formation, and fin outgrowth. After amputating part of the fin, the surrounding epithelium proliferates and migrates over the wound. At 33 °C, this process occurs within six hours post-amputation (hpa, Figure 1B)^6,7. Next, underlying cells from different lineages (ex. bone, blood, glia, fibroblast) re-enter the cell cycle to form a proliferative blastema, while the overlying epidermis continues to proliferate (Figure 1D)⁸. Outgrowth occurs as cells proximal to the blastema re-differentiate into their respective lineages to form new tissue (Figure 1E)⁸. Depending on the level of the amputation, full regeneration is completed in a week to a month.The expression of a large number of gene families, including wnt, hox, fgf, msx, retinoic acid, shh, notch, bmp, and activin-betaA genes, is up-regulated during specific stages of fin regeneration^9-16. However, the roles of these genes and their encoded proteins during regeneration have been difficult to assess, unless a specific inhibitor for the protein exists¹³, a temperature-sensitive mutant exists or a transgenic animal (either overexpressing the wild-type protein or a dominant-negative protein) was generated^7,12. We developed a reverse genetic technique to quickly and easily test the function of any gene during fin regeneration.Morpholino oligonucleotides are widely used to study loss of specific proteins during zebrafish, Xenopus, chick, and mouse development^17-19. Morpholinos basepair with a complementary RNA sequence to either block pre-mRNA splicing or mRNA translation. We describe a method to efficiently introduce fluorescein-tagged antisense morpholinos into regenerating zebrafish fins to knockdown expression of the target protein. The morpholino is micro-injected into each blastema of the regenerating zebrafish tail fin and electroporated into the surrounding cells. Fluorescein provides the charge to electroporate the morpholino and to visualize the morpholino in the fin tissue.This protocol permits conditional protein knockdown to examine the role of specific proteins during regenerative fin outgrowth. In the Discussion, we describe how this approach can be adapted to study the role of specific proteins during wound healing or blastema formation, as well as a potential marker of cell migration during blastema formation.     

Morphological characteristics of worm lizard,Diplometopon zarudnyi (Squamata: Trogonophidae), in the central region of Saudi Arabia

We report morphometric data for 133 specimens of Diplometopon zarudnyi (Squamata: Trogonophidae) collected across its range within Riyadh province of Saudi Arabia. One-way analyses of variance revealed that differences exist in most characters. Snout-vent length and vent-tail length showed slight and inconsistent differences among samples. D. zarudnyi is characterized by 164–175 body annuli; 165–178 dorsal annuli; 13–17 caudal annuli with absence of caudal autotomy. In addition, 2–4 lateral annuli; 45–54 mid-body segments; 39–50 posterior segments; 4–5 head’s plates and 4–6 pre-cloacal pores were recorded in both males and females without gender difference. The present study revealed the widespread distribution of this species in the studied region, since land topography in this area is characterized by the absence of any natural barriers which could restrict the spread of this amphisbaenian lizard D. zarudnyi.     

Correlative light and electron microscopy imaging of autophagy in a zebrafish infection model

High-resolution imaging of autophagy has been used intensively in cell culture studies, but so far it has been difficult to visualize this process in detail in whole animal models. In this study we present a versatile method for high-resolution imaging of microbial infection in zebrafish larvae by injecting pathogens into the tail fin. This allows visualization of autophagic compartments by light and electron microscopy, which makes it possible to correlate images acquired by the 2 techniques. Using this method we have studied the autophagy response against Mycobacterium marinum infection. We show that mycobacteria during the progress of infection are frequently associated with GFP-Lc3-positive vesicles, and that 2 types of GFP-Lc3-positive vesicles were observed. The majority of these vesicles were approximately 1 μm in size and in close vicinity of bacteria, and a smaller number of GFP-Lc3-positive vesicles was larger in size and were observed to contain bacteria. Quantitative data showed that these larger vesicles occurred significantly more in leukocytes than in other cell types, and that approximately 70% of these vesicles were positive for a lysosomal marker. Using electron microscopy, it was found that approximately 5% of intracellular bacteria were present in autophagic vacuoles and that the remaining intracellular bacteria were present in phagosomes, lysosomes, free inside the cytoplasm or occurred as large aggregates. Based on correlation of light and electron microscopy images, it was shown that GFP-Lc3-positive vesicles displayed autophagic morphology. This study provides a new approach for injection of pathogens into the tail fin, which allows combined light and electron microscopy imaging in vivo and opens new research directions for studying autophagy process related to infectious diseases.     

Multi-scale modeling of complex neuronal networks: a view towards striatal cholinergic pattern formations

The phenomena related to brain function occur as the interplay of various modules at different spatial and temporal scales. Particularly, the integration of the dynamical behavior of cells within the complex brain topology reveals a heterogeneous multi-scale problem, which has, to date, mainly been addressed by methods of statistical physics such as mean-field approximations. In contrast, the present study introduces an abstract mathematical model of a deterministic nature that provides a robust integral transformation of the microscopic activities into macroscopic spatiotemporal patterns. The existence of the transformation operator is guaranteed by the convergence of a repetitive patching of the network domain with its fundamental domains that express the local topologies of the tissue. Depending on the choice of the local connectivity function, this framework represents a computationally efficient generalization of the classical Kirchhoff’s, Hebbian, and Hopfield’s approaches. The capabilities of this multi-scale method have been evaluated within the structure of the dorsal striatum of rats, a brain region with major involvement in motor and cognitive information processing. Numerical simulations suggest the formation of characteristic spatiotemporal patterns due to the activation of cholinergic interneurons.