A new hypothesis concerning attachment of parasitic nematodes (Spirurida: Acuarioidea) to the upper alimentary tract of birds

1991 ◽  
Vol 69 (7) ◽  
pp. 1829-1833 ◽  
Author(s):  
Cheryl M. Bartlett
Keyword(s):  
Cross Section ◽  
Alimentary Tract ◽  
External Surface ◽  
Parasitic Nematodes ◽  
Nematode Parasites ◽  
Recurvirostra Americana ◽  
New Hypothesis ◽  
Host Tissues

A gelatinous caplike structure found in vivo around the anterior end of two species of acuarioid nematode parasites (Skrjabinocerca prima Shikhobalova, 1930 and Skrjabinoclava inornatae Wong and Anderson, 1988) is described, termed a "pileus," and suggested as the means by which the nematodes attach to the oesophageal and proventricular mucosa of their bird hosts (Recurvirostra americana and Catoptrophorus semipalmatus inornatus, respectively). Nematodes were embedded in host tissues to the depth of the posteriormost extent of the pileus, which corresponded to the posteriormost extent of the cuticular cordons on the external surface of the anterior end of the nematode. Each cordon, C-shaped in cross section, may serve as a conduit that allows liquid nutrients in the lumen of the alimentary tract to seep into the nematode's mouth, thus enabling the parasite to feed when tightly sealed by the pileus into host tissues.

scholarly journals Characterization of a Rhodanese Homologue from Haemonchus Contortus and its Immune-Modulatory Effects on Goat Immune Cells in Vitro

2020 ◽  
Author(s):  
Yujian Wang ◽  
Muhammad Ehsan ◽  
Jianmei Huang ◽  
Kalibixiati Aimulajiang ◽  
RuoFeng Yan ◽  
...  
Keyword(s):  
Haemonchus Contortus ◽  
Mononuclear Cells ◽  
Small Ruminants ◽  
Parasitic Nematodes ◽  
Dependent Manner ◽  
Peripheral Blood Mononuclear ◽  
Nematode Parasites ◽  
Wide Range

Abstract Background: Suppression and modulation of the immune response of the host by nematode parasites have been reported widely. Rhodaneses or thiosulfate: cyanide sulfurtransferases are present in a wide range of organisms, such as archea, bacteria, fungi, plants and animals. Previously, it was reported that a rhodanese homology could bind by goat peripheral blood mononuclear cells (PBMCs) in vivo.Results: In the present study, we cloned and produced recombinant rhodanese protein originated from Haemonchus contortus (rHCRD), which was one of the parasitic nematodes of small ruminants. The effect of this protein on modulating the immunity of goat PBMC and monocyte was studied in the current work. The predominant localization of the natural HCRD protein was verified as the bowel wall and body surface of worms, according to the immunohistochemical tests. It was proved in this study that the serum produced by artificially infecting goats with H. contortus successfully recognized rHCRD which conjugated goat PBMCs. The rHCRD was co-incubated with goat PBMCs to observe the immunomodulatory effect on proliferation, apoptosis and secretion of cytokines exerted by HCRD. The results showed that the interaction of rHCRD suppressed proliferation of goat PBMCs stimulated by ConA but did not induce the apoptosis of goat PBMCs. After rHCRD exposure, the production of TNF-α and IFN-γ were significantly decreased, however, it significantly increased the secretion of IL-10 and TGF-β1 in goat PBMCs. Phagocytotic assay by FITC-dextran internalization showed that rHCRD inhibited the phagocytosis of goat monocytes. Moreover, rHCRD could down-regulate the expression of MHC-II on goat monocytes in a dose-dependent manner. Conclusions: These discoveries proposed a possible target as immunomodulator, which was potentially beneficial to illuminate the interaction between parasites and hosts in the molecular level and hunt for innovative protein species as candidate targets of drug and vaccine.

scholarly journals On The Relative Importance of Aerobic Metabolism in Small Nematode Parasites of the Alimentary Tract II. the Utilization of Oxygen at Low Partial Pressures by Small Nematode Parasites of the Alimentary Tract

1949 ◽  
Vol 2 (2) ◽  
pp. 166 ◽  
Author(s):  
WP Rogers
Keyword(s):  
Small Intestine ◽  
Haemonchus Contortus ◽  
Alimentary Tract ◽  
Intestinal Parasites ◽  
Low Oxygen ◽  
Nematode Parasites ◽  
Partial Pressures ◽  
Consumption Rates

Nippostrongylus muris, Haemonchus contortus, Nematodirus spathiger, and N. filicollis are all capable of utilizing oxygen for respiratory purposes even when it is present at very low oxygen tensions. Thus with a partial pressure as low as 5 mm. of mercury the respiration of Nippostrongylus muris may reach 40 per cent. of its maximum rate, whereas Nematodirus spp. and H. contortus may respire at 25 and 12 per cent. of their maximum rates respectively. Further, the results indicate that in vivo the oxygen consumption rates may sometimes reach 80 per cent. of the maximum in vitro rate in the case of Nippostrongylus muris in the small intestine of the rat and 40 per cent. in the case of Nematodirus spp. in the small intestine of the sheep. Haemonchus contortus in the sheep abomasums probably respires at a relatively lower rate than either of the intestinal parasites in vivo.

scholarly journals Exosomes secreted by nematode parasites transfer small RNAs to mammalian cells and modulate innate immunity

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Amy H. Buck ◽  
Gillian Coakley ◽  
Fabio Simbari ◽  
Henry J. McSorley ◽  
Juan F. Quintana ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Gastrointestinal Nematode ◽  
Parasitic Nematodes ◽  
Heligmosomoides Polygyrus ◽  
Nematode Parasites ◽  
Intestinal Origin ◽  
Mouse Cells ◽  
Host Tissues

Abstract In mammalian systems RNA can move between cells via vesicles. Here we demonstrate that the gastrointestinal nematode Heligmosomoides polygyrus, which infects mice, secretes vesicles containing microRNAs (miRNAs) and Y RNAs as well as a nematode Argonaute protein. These vesicles are of intestinal origin and are enriched for homologues of mammalian exosome proteins. Administration of the nematode exosomes to mice suppresses Type 2 innate responses and eosinophilia induced by the allergen Alternaria. Microarray analysis of mouse cells incubated with nematode exosomes in vitro identifies Il33r and Dusp1 as suppressed genes, and Dusp1 can be repressed by nematode miRNAs based on a reporter assay. We further identify miRNAs from the filarial nematode Litomosoides sigmodontis in the serum of infected mice, suggesting that miRNA secretion into host tissues is conserved among parasitic nematodes. These results reveal exosomes as another mechanism by which helminths manipulate their hosts and provide a mechanistic framework for RNA transfer between animal species.

Ethnoveterinary plant preparations as livestock dewormers: practices, popular beliefs, pitfalls and prospects for the future

2005 ◽  
Vol 6 (1) ◽  
pp. 91-103 ◽  
Author(s):  
John B. Githiori ◽  
Johan Höglund ◽  
Peter J. Waller
Keyword(s):  
Smallholder Farmers ◽  
Traditional Healers ◽  
Parasitic Infections ◽  
Helminth Parasites ◽  
Nematode Parasites ◽  
Internal Parasites ◽  
The Future ◽  
Livestock Health

AbstractEthnomedicine is an integral part of traditional medical practices in many countries of the developing world. A large proportion of the population uses this form of treatment for primary health care and for the treatment of ailments in their livestock. Livestock is a major asset for resource-poor smallholder farmers and pastoralists throughout the world and internal parasites are recognized by these communities as having an impact on livestock health. Parasitic infections are among those infections that traditional healers confidently treat and against which an enormous variety of remedies exist. Many of these are based on the use of plant preparations. Although various methods have been used for the validation of traditional phytomedical preparations, there is a lack of standardization of these procedures. The present study is aimed at providing an overview of ethnoveterinary deworming preparations, the various methods that have been used in their validation and the future prospects for their use against helminth parasites of ruminant livestock in developing countries, with an emphasis on nematode parasites. Recommendations are made on the procedures that should be followed to conduct in vivo and in vitro assays. Fostering better interaction between traditional healers and scientists is advocated to prevent harmful overexploitation, both of local knowledge and of plant species that may have effects against nematode parasites.

C-Microtubules in Isolated Mitotic Spindles

1971 ◽  
Vol 9 (3) ◽  
pp. 603-619
Author(s):  
W. D. COHEN ◽  
T. GOTTLIEB
Keyword(s):  
Cross Section ◽  
Sea Urchin ◽  
Cross Sections ◽  
Metaphase Chromosome ◽  
Inverse Relationship ◽  
Mitotic Spindles ◽  
Cylindrical Structure ◽  
Arbacia Punctulata ◽  
Alternate Possibility

Microtubules with incomplete cylindrical structure are present in isolated mitotic spindles of the sea urchin, Arbacia punctulata. In cross-section they appear C-shaped, and are thus similar to the ‘C-microtubules’ or ‘C-filaments’ observed previously in other systems. The C-microtubules are not uniformly distributed within isolated spindles, but are typically numerous in the interzonal region of anaphase spindles and in the metaphase chromosome ‘plate’. In chromosome-to-pole regions they are seen much less frequently, and microtubules with the usual O-configuration predominate. Counts of C- and O-microtubules in anaphase spindle cross-sections of known location show an inverse relationship between the number of C-microtubules present and the total number of microtubules present. The observations suggest that the C-microtubules are not simple artifacts of fixation or isolation, but rather may represent a stage of microtubule disassembly which occurs in the interzone during isolation or during anaphase in vivo. The alternate possibility of assembly is not excluded, however. The significance of C-microtubules is further discussed with respect to their occurrence in other systems, and to potential differences between mitotic microtubules.

Adaptation of Cardinal Points Symmetry Landmarks Distribution Model to in-vivo B-Mode Ultrasound Images of Transverse Cross-section of Carotid Arteries

2021 ◽  
Vol 6 (7) ◽  
pp. 107-113
Author(s):  
Charles Nnamdi Udekwe ◽  
Akinlolu Adediran Ponnle
Keyword(s):  
Carotid Artery ◽  
Cross Section ◽  
Carotid Arteries ◽  
Region Of Interest ◽  
Transverse Cross Section ◽  
Transverse Plane ◽  
Distribution Model ◽  
Ultrasound Images ◽  
Symmetry Line

The geometry of the imaged transverse cross-section of carotid arteries in in-vivo B-mode ultrasound images are most times irregular, unsymmetrical, full of speckles and usually non-uniform. We had earlier developed a technique of cardinal point symmetry landmark distribution model (CPS-LDM) to completely characterize the Region of Interest (ROI) of the geometric shape of thick-walled simulated B-mode ultrasound images of carotid artery imaged in the transverse plane, but this was based on the symmetric property of the image. In this paper, this developed technique was applied to completely characterize the region of interest of the geometric shape of in-vivo B-mode ultrasound images of non-uniform carotid artery imaged in the transverse plane. In order to adapt the CPS-LD Model to the in-vivo carotid artery images, the single VS-VS vertical symmetry line common to the four ROIs of the symmetric image is replaced with each ROI having its own VS-VS vertical symmetry line. This adjustment enables the in-vivo carotid artery images possess symmetric properties, hence, ensuring that all mathematical operations of the CPS-LD Model are conveniently applied to them. This adaptability was observed to work well in segmenting the in-vivo carotid artery images. This paper shows the adaptive ability of the developed CPS-LD Model to successfully annotate and segment in-vivo B-mode ultrasound images of carotid arteries in the transverse cross-sectional plane either they are symmetrical or unsymmetrical.

Stiffness of the Gerbil Basilar Membrane: Radial and Longitudinal Variations

2004 ◽  
Vol 91 (1) ◽  
pp. 474-488 ◽  
Author(s):  
Gulam Emadi ◽  
Claus-Peter Richter ◽  
Peter Dallos
Keyword(s):  
Cross Section ◽  
Basilar Membrane ◽  
Organ Of Corti ◽  
Sound Waves ◽  
Motion Patterns ◽  
Longitudinal Stiffness ◽  
Longitudinal Variations ◽  
Space Constant ◽  
Qualitative Changes

Experimental data on the mechanical properties of the tissues of the mammalian cochlea are essential for understanding the frequency- and location-dependent motion patterns that result in response to incoming sound waves. Within the cochlea, sound-induced vibrations are transduced into neural activity by the organ of Corti, the gross motion of which is dependent on the motion of the underlying basilar membrane. In this study we present data on stiffness of the gerbil basilar membrane measured at multiple positions within a cochlear cross section and at multiple locations along the length of the cochlea. A basic analysis of these data using relatively simple models of cochlear mechanics reveals our most important result: the experimentally measured longitudinal stiffness gradient at the middle of the pectinate zone of the basilar membrane (4.43 dB/mm) can account for changes of best frequency along the length of the cochlea. Furthermore, our results indicate qualitative changes of stiffness-deflection curves as a function of radial position; in particular, there are differences in the rate of stiffness growth with increasing tissue deflection. Longitudinal coupling within the basilar membrane/organ of Corti complex is determined to have a space constant of 21 μm in the middle turn of the cochlea. The bulk of our data was obtained in the hemicochlea preparation, and we include a comparison of this set of data to data obtained in vivo.

Bite force and jaw biomechanics in the subterranean rodent Talas tuco-tuco (Ctenomys talarum) (Caviomorpha: Octodontoidea)

2011 ◽  
Vol 89 (4) ◽  
pp. 334-342 ◽  
Author(s):  
Federico Becerra ◽  
Alejandra Echeverría ◽  
Aldo Iván Vassallo ◽  
Adrià Casinos
Keyword(s):  
Cross Section ◽  
Force Transducer ◽  
Bite Force ◽  
Adult Males ◽  
Subterranean Rodent ◽  
Soil Hardness ◽  
Ctenomys Talarum ◽  
Adductor Muscles ◽  
Typical Habitat

The Talas tuco-tuco ( Ctenomys talarum Thomas, 1898) is a South American subterranean rodent that digs using both forelimbs and incisors, the latter being used when animals face hard soils and fibrous roots. In this rodent, the incisors are also used during intermale competition for mates. Bite forces were measured on wild females (n = 21) and males (n = 21) (both adult and young individuals) using a force transducer. Bite force was significantly higher in adult males than in females (32 vs. 27 N, respectively). Bite forces calculated on the physiological cross-section of jaw adductor muscles in dissected specimens were slightly higher than in vivo measurements. Regressions against body mass showed that bite force scaled with positive allometry, with slopes of 0.89 (females) and 0.99 (males). No significant differences were observed, neither in the slope nor in the y intercept of both sexes’ equations; therefore intersexual differences in bite forces observed in adults should mainly be due to size dimorphism. Considering that soil hardness of C. talarum’s typical habitat averages 100 N/cm2, and taking into account incisor’s cross-section, it was assessed that the pressure exerted by jaw adductor muscles at the incisors level is three times higher than that required for soil penetration.

scholarly journals Some larval morphological characteristics of Camelostrongylus mentulatus and Nematodirus spathiger

2020 ◽  
Vol 3 (2) ◽  
pp. 7-11
Author(s):  
A. Saidi ◽  
R. Mimouni ◽  
F. Hamadi ◽  
W. Oubrou
Keyword(s):  
Morphological Characteristics ◽  
Gastrointestinal Nematode ◽  
Parasitic Nematodes ◽  
Morphological Identification ◽  
Morphological Pattern ◽  
Wild Ruminants ◽  
Nematode Parasites ◽  
Domestic Ruminants ◽  
Teladorsagia Circumcincta ◽  
Camelostrongylus Mentulatus

Monitoring of gastrointestinal nematode parasites in ruminants (domestic and wild) is often based on fecal examination techniques, looking for excreted eggs and larval forms using morphological keys. These, are more available in domestic ruminants, in which helminths are widely studied, than in wild ruminants.  This study tried to provide certain morphological elements that will help to recognize the L3 larvae of Camelostrongylus mentulatus and Nematodirus spathiger that could parasite either domestic or wild ruminants. For that, we resorted first to the culture of L3 larvae from fecal samples taken from African antelopes, and second by the microscopic characterization of each isolated larval morphological pattern previously identified by sequencing of its internal transcribed spacer (ITS-2) regions of the ribosomal DNA. The results of different microscopic captured images showed that Camelostrongylus mentulatus larva is 16 intestinal cells that measuring approximately 820 µm length, ‎≈ 25 µm wide, and ‎≈ 47 µm for its sheath tail extension and by this be closer to Teladorsagia circumcincta characteristics.  For Nematodirus spathiger, it possesses 8 gut cells and measuring about 1020 µm long, ‎≈ 25 µm wide, and‎ ≈ 143 µm for its sheath tail extension with specific tail appendages. Have done this, we were able to get some clarifications on the morphology of the studied larvae, and we believe thus that this study will contribute to the establishment of morphological identification keys especially for parasitic nematodes of wild ruminants.

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