bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assemblage of benthic macrofauna in the aggregates of the tubiculous worm Phyllochaetopterus socialis in the Mar del Plata harbour, Argentina
Authors: Albano Mariano J. , Obenat Sandra M. 
Published: June 2009

The assemblage and the temporal changes of benthic macrofauna inhabiting the Phyllochaetopterus socialis (Polychaeta: Chaetopteridae) aggregates were analysed during 2004 and May 2005 in the Mar del Plata harbour, Buenos Aires (Argentina). Species composition, abundance, richness and diversity were estimated from monthly or bimonthly samples obtained by SCUBA diving. Multivariate (MDS) and SIMPER analyses were applied to analyse the structure of benthic communities. In the mats, a total of 57 species (invertebrates and chordates) belonging to 11 phyla were associated to P. socialis: crustaceans and molluscs were the most abundant species and crustaceans and polychaetes were the most diverse groups (14 and 11 species richness, respectively). The mean abundance ranged from 79.67±57.47 ind/250 ml to 718.75 ind/250 ml (mean±SD). The amphipod Monocorophium insidiosum, the gastropod Anachis isabellei and the tanaidacean Leptognathia sp. were the most representative species in the mats. Richness and diversity in P. socialis aggregates were higher than in surrounding sediments. Results show significant differences among months in composition, abundance and feeding guilds of the macrofauna associated with the mats. The assemblage of benthic macrofauna with permanent and temporary organisms in P. socialis aggregates suggests the existence of microhabitats in the mats that provide substrate, refuges for predation and availability of food increasing richness and diversity. These results allow considering P. socialis as an autogenic ecosystem engineer in the Mar del Plata harbour.
Notes on oviposition and demography of a shallow water population of the edible snail Zidona dufresnei (Caenogastropoda: Volutidae) living in San Antonio Bay (northern Patagonia, Argentina)
Authors: Pereyra Patricio Javier , Narvarte Maite Andrea , Martín Pablo Rafael 
Published: June 2009

Zidona dufresnei (Donovan, 1823) is a big-sized and long-lived snail endemic to the south-western Atlantic where it dwells in sandy bottoms between five and 115 m; females lay big egg capsules from which crawling juveniles emerge. An unusual population of Z. dufresnei inhabits the low intertidal and shallow subtidal zone of San Antonio Bay, the southernmost location of the species, where it faces many threats. The aim of this study is to describe some of the demographic and reproductive characteristics of this population and to compare them to those located in northern zones. Monthly samples of adults and egg capsules were obtained from October to April and their position was recorded; snails and capsules were gathered for examination in the laboratory. Sex-ratio was near 1:1 for the whole sampling period and the size–frequency distributions were similar for both sexes; females were wider and heavier than males at the same shell length. Maximum shell length was 120.5 mm in our study and so no female reached the minimum size at first gonadal maturity reported for other populations (128 mm); female size seems to limit the capsule diameter and the number and size of embryos that are lower than in other populations. Egg capsule and adult densities in the intertidal zone peaked in February and March respectively, averaging 1.34 capsules and 1.91 snails by 100 m2 during the sampling period; egg capsule deposition elapsed from November to March and peaked in December; females select cobble by size to lay egg capsules. Due to its restricted distribution and the low juvenile and adult dispersal, the unusual Z. dufresnei population dwelling in San Antonio Bay seems to be quite vulnerable to diverse anthropogenic impacts.
Predatory and reproductive responses of the estuarine whelk Thais gradata (Caenogastropoda: Muricidae) to novel colonization by Musculista senhousia (Bivalvia: Mytilidae)
Authors: Marshall David J. 
Published: June 2009

Novel predator–prey interactions are becoming increasingly relevant to investigate in the context of current geographical range expansions and biological invasions. This study describes a vigorous attack by a muricid whelk, Thais gradata on a mud-inhabiting mytilid mussel, Musculista senhousia, following new colonization of the mussel in the Brunei estuarine system (Borneo, South-East Asia). This represents only the second reported attack by a gastropod on this globally important invasive mussel species, and the first such attack in its native environment. Whelks migrated from their typical hard surface habitat and barnacle feeding to the sediment, where they aggregated and fed on the mussels. Field data suggest no selection by the whelks of the part of the mussel bed colonized or of the prey size attacked (median shell length = 21 mm). In addition to forming feeding aggregations, the whelks formed non-feeding resting aggregations off the mussel bed (sometimes of more than 80 individuals). These apparently facilitated synchronized mating and consequently the formation of large communal nests of egg capsules (involving approximately 3500 contributing females). During the investigation, the newly-formed mussel colony underwent mass mortality, and the whelks either redistributed on the sediment or returned to feeding on barnacles. The population-level response by the whelks described here maximizes energy transfer from prey resource to whelk propagation. In addition to the whelk's generality of habitat use and feeding behaviour, this is likely to contribute to sustaining populations in a system where prey abundance and distribution is limited by highly variable and extreme physicochemical conditions.
Helminth species richness in wild wood mice,Apodemus sylvaticus, is enhanced by the presence of the intestinal nematodeHeligmosomoides polygyrus
Authors: BEHNKE J. M. , EIRA C. , ROGAN M. , GILBERT F. S. , TORRES J. , MIQUEL J. , LEWIS J. W. 
Published: June 2009

SUMMARYWe analysed 3 independently collected datasets of fully censused helminth burdens in wood mice,Apodemus sylvaticus, testing thea priorihypothesis of Behnkeet al.(2005) that the presence of the intestinal nematodeHeligmosomoides polygyruspredisposes wood mice to carrying other species of helminths. In Portugal, mice carryingH. polygyrusshowed a higher prevalence of other helminths but the magnitude of the effect was seasonal. In Egham, mice withH. polygyrusshowed a higher prevalence of other helminth species, not confounded by other factors. In Malham Tarn, mice carryingH. polygyruswere more likely to be infected with other species, but only among older mice. Allowing for other factors, heavy residualH. polygyrusinfections carried more species of other helminths in both the Portugal and Egham data; species richness in Malham was too low to conduct a similar analysis, but asH. polygyrusworm burdens increased, so the prevalence of other helminths also increased. Our results support those of Behnkeet al.(2005), providing firm evidence that at the level of species richness a highly predictable element of co-infections in wood mice has now been defined: infection withH. polygyrushas detectable consequences for the susceptibility of wood mice to other intestinal helminth species.
Familial aggregation of human helminth infection in the Poyang lake area of China with a focus on genetic susceptibility to schistosomiasis japonica and associated markers of disease
Authors: ELLIS M. K. , McMANUS D. P. 
Published: June 2009

SUMMARYHuman helminthiases are common in China, especially in rural areas where sanitation conditions are poor. Soil-transmitted helminths (STHs) are predominantly found in the southern provinces.Schistosoma japonicumis also endemic to southern China. Here we review the prevalence of helminth infections and polyparasitism in China, and discuss the interactions between helminth parasites in the co-infected host. It is clear that STHs are more prevalent in rural China than previously suggested emphasizing the need for systematic control of STHs. Further, the need for improved sanitation and hygiene conditions to prevent parasite transmission is highlighted. We provide supporting evidence for human genetic susceptibility to both single helminth infection and polyparasitism, and suggest that susceptibility to helminths infections may not be independent of one or the other. We demonstrate an association between single nucleotide polymorphism (SNP) variants in IL-5 and symptomaticS. japonicuminfection and discuss the potential role of IL-5 in other helminth infections. Fundamental to disease and morbidity control is adequate and effective diagnosis and surveillance of disease. We discuss the role of sICAM-1 and TNFR-I and -II as candidate markers for schistosome-induced hepatomegaly and fibrosis, and their potential for assessing disease stage and progression in schistosomiasis.
Ecological Immunology of mosquito-malaria interactions: Of non-natural versus natural model systems and their inferences
Authors: TRIPET F. 
Published: June 2009

SUMMARYThere has been a recent shift in the literature on mosquito/Plasmodiuminteractions with an increasingly large number of theoretical and experimental studies focusing on their population biology and evolutionary processes. Ecological immunology of mosquito-malaria interactions – the study of the mechanisms and function of mosquito immune responses toPlasmodiumin their ecological and evolutionary context – is particularly important for our understanding of malaria transmission and how to control it. Indeed, describing the processes that create and maintain variation in mosquito immune responses and parasite virulence in natural populations may be as important to this endeavor as describing the immune responses themselves. For historical reasons, Ecological Immunology still largely relies on studies based on non-natural model systems. There are many reasons why current research should favour studies conducted closer to the field and more realistic experimental systems whenever possible. As a result, a number of researchers have raised concerns over the use of artificial host-parasite associations to generate inferences about population-level processes. Here I discuss and review several lines of evidence that, I believe, best illustrate and summarize the limitations of inferences generated using non-natural model systems.
Calbindin and calretinin localization in retina from different species
Authors: Pasteels Brigitte , Rogers John , Blachier François , Pochet Roland 
Published: June 2009

AbstractCalbindin-D28K and calretinin are homologous calcium-binding proteins localized in many neurons of the central nervous system. We have compared polyclonal antibodies against calbindin and calretinin and have shown by western blots using purified calbindin and calretinin from rat that (1) anti-calretinin does not recognize calbindin and (2) anti-calbindin presents some cross-reactivity with calretinin.In this report, we have compared by immunohistochemistry the localization of both calcium-binding proteins in the retina of monkey, pig, sheep, rat, cat, pigeon, and salamander. These results are compared with previous data for chick. There are many differences between species and not within species, but some aspects of the distribution are conserved. All species, except rat and monkey, have some cones which contain calbindin only. Most species also have some bipolar cells containing calbindin only. Calretinin is rarely seen in photoreċeptors or bipolar cells. All species have horizontal cells which contain calretinin or calbindin or both. All species have amacrine cells and ganglion cells containing one or other protein.In the cat ganglion cell layer, the calretinin antisera define a new, asymmetric, type of cell.
Independent eye movements in the turtle
Authors: Ariel M. 
Published: June 2009

AbstractIn order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).
A burst of differentiation in the outer posterior retina of the eleven-week human fetus: An ultrastructural study
Authors: Linberg Kenneth A. , Fisher Steven K. 
Published: June 2009

AbstractMany studies on human retinal development have cited the third gestational month as a period when the posterior retina undergoes rapid differentiation and maturation, including a lining up of cone precursors. Ultrastructural data on the posterior retina during the third month are very limited, and totally lacking for the cone monolayer. We have examined two human fetal retinas between ten and 11 gestational weeks. Before the appearance of the cone monolayer, the outer neural retina consists of a homogeneous population of undifferentiated neuroblasts. Mitotic figures are still evident, even posteriorally. There is no outer plexiform layer (OPL). The interface of neural retina to retinal pigment epithelium (RPE) is largely featureless. By 11 weeks, the posterior retina has a thin OPL that separates the many rows of cells in the developing inner nuclear layer from the single tier of macular cone precursors. The RPE monolayer consists of cuboidal cells whose apical surface elaborates ridges of cytoplasm and branched processes that project into the subretinal space. The large, cuboidal cones are linked to each other and Müller cells at the outer limiting membrane. They show definitive signs of the structural polarity typical of vertebrate photoreceptors. Their apical cytoplasm contains many organelles common to the inner segment, while the basal cytoplasm has synaptic ribbons and vesicles, and receives invaginating contacts from processes in the OPL neuropil arising from differentiating second-order neurons. Lateral cone surfaces are mutually underlain by large subsurface cisterns.
Antibody labeling of functional subdivisions in visual cortex: Cat-301 immunoreactivity in striate and extrastriate cortex of the macaque monkey
Authors: Deyoe Edgar A. , Hockfield Susan , Garren Hideki , Van Essen David C. 
Published: June 2009

AbstractWe have examined the distribution of immunoreactivity for the monoclonal antibody Cat-301 in visual cortex of the macaque monkey. Remarkably, those portions of striate cortex (V1) and extrastriate cortex that are most immunoreactive for Cat-301 are anatomically interconnected and are dominated by inputs arising from the magnocellular layers of the LGN (which are themselves highly immunoreactive). In particular, we found that a band of Cat-301 labeled neurons known to exist in layer 4 of V1 is centered on the boundary between layers 4Cα and 4B and thus includes portions of both the primary target of the magnocellular LGN and its subsequent relay through layer 4B. We also demonstrated consistently strong Cat-301 immunoreactivity in all three extrastriate targets of layer 4B: areas V3, MT, and the cytochrome-oxidase (CO) enriched thick stripes of V2. In V2, there was a close correlation between Cat-301 labeling and clusters of cells projecting to MT but not to V4. This was true even in regions where the CO pattern was equivocal or irregular, indicating that Cat-301 is a more reliable marker than CO for the thick-stripe subregions of V2. Finally, we found strong Cat-301 immunoreactivity in at least parts of areas V3A, the MST complex, and the posterior parietal complex, but not in area V4 or inferotemporal cortex. The molecular specificity revealed by this single marker thus correlates with functionally specific subdivisions at each hierarchical level over nearly the entire known extent of the visual pathway in macaques. This supports the notion that these subdivisions form an anatomically, physiologically, and now molecularly distinct pathway known as the M-stream.
Distribution of uncrossed and crossed retinofugal axons in the cat optic nerve and their relationship to patterns of fasciculation
Authors: Jeffery Glen 
Published: June 2009

AbstractThe course of optic axons that take different routes at the chiasm have been traced through horizontally sectioned optic nerves in the cat, after unilateral injections of horseradish peroxide into the optic tract. Behind the eye and for most of the course of the nerve, nearly all of the axons that remain uncrossed at the chiasm are located in a retinotopically appropriate position, in the lateral aspect of the nerve. However, in the most caudal segment of the nerve an increasing proportion of these axons are located in regions that are retinotopically inappropriate. Just before the nerve joins the chiasm, uncrossed axons can be found across the full medio-lateral extent of the nerve, although there is still a relative increase in their density laterally.Labeled axons that cross at the chiasm course in a relatively parallel manner along the greater proportion of the nerve. However, in the caudal segment of the nerve their relative positions change and they appear to course in an irregular manner. This occurs where the uncrossed projection becomes increasingly more widespread.Axons in the optic nerve are grouped into fascicules. This pattern of organization also changes in the caudal region of the nerve. Although clear fascicular patterns are present along the greater part of the nerve, they become progressively less distinct caudally. The change in the pattern of fasciculation occurs over the same region of the nerve as the relative changes in axon trajectory and distribution.These results demonstrate that irrespective of chiasmatic route, optic axons in the cat are reorganized in the caudal segment of the nerve. This reorganization is not confined to changes in relative axon position, but is reflected in the structure of the nerve by the change of axon grouping from a fascicular to a non-fascicular arrangement.
Short latency ocular-following responses in man
Authors: Gellman R.S. , Carl J.R. , Miles F.A. 
Published: June 2009

AbstractThe ocular-following responses elicited by brief unexpected movements of the visual scene were studied in human subjects. Response latencies varied with the type of stimulus and decreased systematically with increasing stimulus speed but, unlike those of monkeys, were not solely determined by the temporal frequency generated by sine-wave stimuli. Minimum latencies (70–75 ms) were considerably shorter than those reported for other visually driven eye movements. The magnitude of the responses to sine-wave stimuli changed markedly with stimulus speed and only slightly with spatial frequency over the ranges used. When normalized with respect to spatial frequency, all responses shared the same dependence on temporal frequency (band-pass characteristics with a peak at 16 Hz), indicating that temporal frequency, rather than speedper se, was the limiting factor over the entire range examined. This suggests that the underlying motion detectors respond to the local changes in luminance associated with the motion of the scene. Movements of the scene in the immediate wake of a saccadic eye movement were on average twice as effective as movements 600 ms later: post-saccadic enhancement. Less enhancement was seen in the wake of saccade-like shifts of the scene, which themselves elicited weak ocular following, something not seen in the wake of real saccades. We suggest that there are central mechanisms that, on the one hand, prevent the ocular-following system from tracking the visual disturbances created by saccades but, on the other, promote tracking of any subsequent disturbance and thereby help to suppress post-saccadic drift. Partitioning the visual scene into central and peripheral regions revealed that motion in the periphery can exert a weak modulatory influence on ocular-following responses resulting from motion at the center. We suggest that this may help the moving observer to stabilize his/her eyes on nearby stationary objects.