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Bowden TJ, Kraev I, Lange S. Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca-The Blue Mussel ( Mytilus edulis), Soft Shell Clam ( Mya arenaria), Eastern Oyster ( Crassostrea virginica) and Atlantic Jacknife Clam ( Ensis leei). BIOLOGY 2020; 9:biology9120416. [PMID: 33255637 PMCID: PMC7760292 DOI: 10.3390/biology9120416] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/20/2022]
Abstract
Simple Summary Oysters and clams form an important component of the food chain and food security and are of considerable commercial value worldwide. They are affected by pollution and climate change, as well as a range of infections, some of which are opportunistic. For aquaculture purposes they are furthermore of great commercial value and changes in their immune responses can also serve as indicators of changes in ocean environments. Therefore, studies into understanding new factors in their immune systems may aid new biomarker discovery and are of considerable value. This study assessed new biomarkers relating to changes in protein function in four economically important marine molluscs, the blue mussel, soft shell clam, Eastern oyster, and Atlantic jacknife clam. These findings indicate novel regulatory mechanisms of important metabolic and immunology related pathways in these mollusks. The findings provide new understanding to how these pathways function in diverse ways in different animal species as well as aiding new biomarker discovery for Mollusca aquaculture. Abstract Oysters and clams are important for food security and of commercial value worldwide. They are affected by anthropogenic changes and opportunistic pathogens and can be indicators of changes in ocean environments. Therefore, studies into biomarker discovery are of considerable value. This study aimed at assessing extracellular vesicle (EV) signatures and post-translational protein deimination profiles of hemolymph from four commercially valuable Mollusca species, the blue mussel (Mytilus edulis), soft shell clam (Mya arenaria), Eastern oyster (Crassostrea virginica), and Atlantic jacknife clam (Ensis leei). EVs form part of cellular communication by transporting protein and genetic cargo and play roles in immunity and host–pathogen interactions. Protein deimination is a post-translational modification caused by peptidylarginine deiminases (PADs), and can facilitate protein moonlighting in health and disease. The current study identified hemolymph-EV profiles in the four Mollusca species, revealing some species differences. Deiminated protein candidates differed in hemolymph between the species, with some common targets between all four species (e.g., histone H3 and H4, actin, and GAPDH), while other hits were species-specific; in blue mussel these included heavy metal binding protein, heat shock proteins 60 and 90, 2-phospho-D-glycerate hydrolyase, GTP cyclohydrolase feedback regulatory protein, sodium/potassium-transporting ATPase, and fibrinogen domain containing protein. In soft shell clam specific deimination hits included dynein, MCM3-associated protein, and SCRN. In Eastern oyster specific deimination hits included muscle LIM protein, beta-1,3-glucan-binding protein, myosin heavy chain, thaumatin-like protein, vWFA domain-containing protein, BTB domain-containing protein, amylase, and beta-catenin. Deiminated proteins specific to Atlantic jackknife clam included nacre c1q domain-containing protein and PDZ domain-containing protein In addition, some proteins were common as deiminated targets between two or three of the Bivalvia species under study (e.g., EP protein, C1q domain containing protein, histone H2B, tubulin, elongation factor 1-alpha, dominin, extracellular superoxide dismutase). Protein interaction network analysis for the deiminated protein hits revealed major pathways relevant for immunity and metabolism, providing novel insights into post-translational regulation via deimination. The study contributes to EV characterization in diverse taxa and understanding of roles for PAD-mediated regulation of immune and metabolic pathways throughout phylogeny.
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Affiliation(s)
- Timothy J. Bowden
- Aquaculture Research Institute, School of Food & Agriculture, University of Maine, Orono, ME 04469-5735, USA;
| | - Igor Kraev
- Electron Microscopy Suite, Faculty of Science, Technology, Engineering and Mathematics, Open University, Milton Keynes MK7 6AA, UK;
| | - Sigrun Lange
- Tissue Architecture and Regeneration Research Group, School of Life Sciences, University of Westminster, London W1W 6UW, UK
- Correspondence: ; Tel.: +44-(0)207-911-5000
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Qin N, Sun H, Lu M, Wang J, Tang T, Liu F. A single von Willebrand factor C-domain protein acts as an extracellular pattern-recognition receptor in the river prawn Macrobrachium nipponense. J Biol Chem 2020; 295:10468-10477. [PMID: 32532819 DOI: 10.1074/jbc.ra120.013270] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/02/2020] [Indexed: 01/08/2023] Open
Abstract
The single von Willebrand factor C-domain proteins (SVWCs) are mainly found in arthropods. Their expression may be regulated by several environmental stresses, including nutritional status and bacterial and viral infections. However, the underlying regulatory mechanism is unclear. In the present study, we identified a member of the SVWC family from the river prawn Macrobrachium nipponense as a soluble and bacteria-inducible pattern-recognition receptor (designated MnSVWC). In vitro, recombinant MnSVWC exhibited pronounced binding and Ca2+-dependent agglutinating abilities against diverse microbes, including Gram-negative bacteria (i.e. Escherichia coli and Aeromonas victoria), Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), and yeast (Pichia pastoris). ELISA assays revealed that recombinant MnSVWC recognizes a broad range of various pathogen-associated molecular patterns (PAMPs) and has high affinity to lipopolysaccharide and lysine-type and diaminopimelic acid-type peptidylglycan and d-galactose and low affinity to d-mannan and β-1,3-glucan. Mutant MnSVWCP57A with an impaired Glu-Pro-Asn (EPN) motif displayed reduced affinity to all these PAMPs to varying extent. Moreover, MnSVWC bound to the surface of hemocytes and promoted their phagocytic activity and clearance of invasive bacteria. RNAi-mediated MnSVWC knockdown in prawn reduced the ability to clear invading bacteria, but did not block the activities of the Toll pathway or the arthropod immune deficiency (IMD) pathway, or the expression of antimicrobial peptide genes. These results indicate that MnSVWC functions as an extracellular pattern-recognition receptor in M. nipponense that mediates cellular immune responses by recognizing PAMPs, agglutinating invasive microbes, and promoting phagocytosis in hemocytes.
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Affiliation(s)
- Nan Qin
- The Key Laboratory of Zoological Systematics and Application, College of Life Sciences, Hebei University, Baoding, China
| | - Hehe Sun
- The Key Laboratory of Zoological Systematics and Application, College of Life Sciences, Hebei University, Baoding, China
| | - Meike Lu
- The Key Laboratory of Zoological Systematics and Application, College of Life Sciences, Hebei University, Baoding, China
| | - Jianhui Wang
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ting Tang
- The Key Laboratory of Zoological Systematics and Application, College of Life Sciences, Hebei University, Baoding, China .,Institute of Life Science and Green Development, Hebei University, Baoding, China
| | - Fengsong Liu
- The Key Laboratory of Zoological Systematics and Application, College of Life Sciences, Hebei University, Baoding, China .,Institute of Life Science and Green Development, Hebei University, Baoding, China
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Skála V, Walker AJ, Horák P. Snail defence responses to parasite infection: The Lymnaea stagnalis-Trichobilharzia szidati model. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 102:103464. [PMID: 31402190 DOI: 10.1016/j.dci.2019.103464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Lymnaea stagnalis is a common freshwater gastropod. Importantly, the snail serves as the intermediate host for more than one hundred species of digenetic trematodes, including the avian schistosome Trichobilharzia szidati, a causative agent of cercarial dermatitis in humans. Infection of L. stagnalis by T. szidati initiates a dynamic confrontation between the host and the parasite that culminates in immunocompatibility ensuring survival and development of larvae. Unfortunately, the molecular mechanisms determining this immunocompatibility remain poorly characterised. By employing a variety of immune elicitors, including chemical compounds, PAMPs and bacteria, research in the last two decades has elucidated some of the molecular processes that regulate the snail internal defence response such as haemocyte signalling pathways. These discoveries provide a framework for future studies of molecular interactions between T. szidati and L. stagnalis to help elucidate factors and mechanisms enabling transmission of schistosome parasites. Moreover, support from recently available next generation sequence data and CRISPR-enabled functional genomics should further enable L. stagnalis as an important model for comparative immunology and contribute to a more comprehensive understanding of immune functions in gastropod molluscs.
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Affiliation(s)
- Vladimír Skála
- General University Hospital and the First Faculty of Medicine of Charles University, Institute of Medical Biochemistry and Laboratory Diagnostics, Prague, Czech Republic; Charles University, First Faculty of Medicine, Institute of Immunology and Microbiology, Prague, Czech Republic.
| | - Anthony J Walker
- Kingston University, Molecular Parasitology Laboratory, School of Life Sciences Pharmacy and Chemistry, Kingston upon Thames, Surrey, United Kingdom
| | - Petr Horák
- Charles University, Faculty of Science, Department of Parasitology, Prague, Czech Republic
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Adekiya TA, Aruleba RT, Oyinloye BE, Okosun KO, Kappo AP. The Effect of Climate Change and the Snail-Schistosome Cycle in Transmission and Bio-Control of Schistosomiasis in Sub-Saharan Africa. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 17:E181. [PMID: 31887979 PMCID: PMC6981654 DOI: 10.3390/ijerph17010181] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 01/30/2023]
Abstract
In the next century, global warming, due to changes in climatic factors, is expected to have an enormous influence on the interactions between pathogens and their hosts. Over the years, the rate at which vector-borne diseases and their transmission dynamics modify and develop has been shown to be highly dependent to a certain extent on changes in temperature and geographical distribution. Schistosomiasis has been recognized as a tropical and neglected vector-borne disease whose rate of infection has been predicted to be elevated worldwide, especially in sub-Saharan Africa; the region currently with the highest proportion of people at risk, due to changes in climate. This review not only suggests the need to develop an efficient and effective model that will predict Schistosoma spp. population dynamics but seeks to evaluate the effectiveness of several current control strategies. The design of a framework model to predict and accommodate the future incidence of schistosomiasis in human population dynamics in sub-Saharan Africa is proposed. The impact of climate change on schistosomiasis transmission as well as the distribution of several freshwater snails responsible for the transmission of Schistosoma parasites in the region is also reviewed. Lastly, this article advocates for modelling several control mechanisms for schistosomiasis in sub-Saharan Africa so as to tackle the re-infection of the disease, even after treating infected people with praziquantel, the first-line treatment drug for schistosomiasis.
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Affiliation(s)
- Tayo Alex Adekiya
- Biotechnology and Structural Biology Group, Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa; (R.T.A.); (B.E.O.)
| | - Raphael Taiwo Aruleba
- Biotechnology and Structural Biology Group, Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa; (R.T.A.); (B.E.O.)
| | - Babatunji Emmanuel Oyinloye
- Biotechnology and Structural Biology Group, Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa; (R.T.A.); (B.E.O.)
- Department of Biochemistry, Afe Babalola University, PMB 5454, Ado-Ekiti 360001, Nigeria
| | - Kazeem Oare Okosun
- Department of Mathematics, Vaal University of Technology, Vanderbijlpark 1900, South Africa;
| | - Abidemi Paul Kappo
- Biotechnology and Structural Biology Group, Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa; (R.T.A.); (B.E.O.)
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Horák P, Mikeš L, Lichtenbergová L, Skála V, Soldánová M, Brant SV. Avian schistosomes and outbreaks of cercarial dermatitis. Clin Microbiol Rev 2015; 28:165-90. [PMID: 25567226 PMCID: PMC4284296 DOI: 10.1128/cmr.00043-14] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cercarial dermatitis (swimmer's itch) is a condition caused by infective larvae (cercariae) of a species-rich group of mammalian and avian schistosomes. Over the last decade, it has been reported in areas that previously had few or no cases of dermatitis and is thus considered an emerging disease. It is obvious that avian schistosomes are responsible for the majority of reported dermatitis outbreaks around the world, and thus they are the primary focus of this review. Although they infect humans, they do not mature and usually die in the skin. Experimental infections of avian schistosomes in mice show that in previously exposed hosts, there is a strong skin immune reaction that kills the schistosome. However, penetration of larvae into naive mice can result in temporary migration from the skin. This is of particular interest because the worms are able to migrate to different organs, for example, the lungs in the case of visceral schistosomes and the central nervous system in the case of nasal schistosomes. The risk of such migration and accompanying disorders needs to be clarified for humans and animals of interest (e.g., dogs). Herein we compiled the most comprehensive review of the diversity, immunology, and epidemiology of avian schistosomes causing cercarial dermatitis.
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Affiliation(s)
- Petr Horák
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Libor Mikeš
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Lucie Lichtenbergová
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Vladimír Skála
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Miroslava Soldánová
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - Sara Vanessa Brant
- Museum Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
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Tremblay A, Gilbert JA. Milk products, insulin resistance syndrome and type 2 diabetes. J Am Coll Nutr 2009; 28 Suppl 1:91S-102S. [PMID: 19571167 DOI: 10.1080/07315724.2009.10719809] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A growing body of evidence suggests an inverse relationship between calcium and vitamin D status and dairy food intake and the development of the insulin resistance syndrome (IRS) and type 2 diabetes mellitus (t2DM). Observational studies show a consistent inverse association between dairy intake and the prevalence of IRS and t2DM. In a systematic review of the observational evidence, the odds for developing the IRS was 0.71 (95% CI, 0,57-0.89) for the highest dairy intake (3-4 servings/d) vs. the lowest intake (0.9-1.7 servings/d). Few interventional studies have been conducted to evaluate the effects of dairy food intake on the management of prevention of IRS or t2DM. Intervention studies that have examined the independent effects of dairy intake on specific metabolic components of the IRS including blood pressure and obesigenic parameters have shown favorable effects that support the observational findings albeit the results have been less consistent. Many metabolic and dietary factors appear to influence the degree to which dairy affects IRS metabolic parameters including calcium and vitamin D intake status, BMI, ethnicity and age. Overall, the intake of low-fat dairy products is a feature of a healthy dietary pattern which has been shown to contribute to a significant extent to the prevention of IRS.
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Kemp C, Imler JL. Antiviral immunity in drosophila. Curr Opin Immunol 2009; 21:3-9. [PMID: 19223163 DOI: 10.1016/j.coi.2009.01.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 01/20/2009] [Indexed: 12/21/2022]
Abstract
Genetic analysis of the drosophila antiviral response indicates that RNA interference plays a major role. This contrasts with the situation in mammals, where interferon-induced responses mediate innate antiviral host-defense. An inducible response also contributes to antiviral immunity in drosophila, and similarities in the sensing and signaling of viral infection are becoming apparent between drosophila and mammals. In particular, DExD/H box helicases appear to play a crucial role in the cytosolic detection of viral RNAs in flies and mammals.
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Affiliation(s)
- Cordula Kemp
- CNRS-UPR, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
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Zaitseva OV, Kuznetsova TV, Markosova TG. NADPH-diaphorase activity in the digestive system of gastropod molluscs Achatina fulica and Littorina littorea. J EVOL BIOCHEM PHYS+ 2009. [DOI: 10.1134/s002209300901013x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Deddouche S, Matt N, Budd A, Mueller S, Kemp C, Galiana-Arnoux D, Dostert C, Antoniewski C, Hoffmann JA, Imler JL. The DExD/H-box helicase Dicer-2 mediates the induction of antiviral activity in drosophila. Nat Immunol 2008; 9:1425-32. [PMID: 18953338 DOI: 10.1038/ni.1664] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 09/09/2008] [Indexed: 11/08/2022]
Abstract
Drosophila, like other invertebrates and plants, relies mainly on RNA interference for its defense against viruses. In flies, viral infection also triggers the expression of many genes. One of the genes induced, Vago, encodes a 18-kilodalton cysteine-rich polypeptide. Here we provide genetic evidence that the Vago gene product controlled viral load in the fat body after infection with drosophila C virus. Induction of Vago was dependent on the helicase Dicer-2. Dicer-2 belongs to the same DExD/H-box helicase family as do the RIG-I-like receptors, which sense viral infection and mediate interferon induction in mammals. We propose that this family represents an evolutionary conserved set of sensors that detect viral nucleic acids and direct antiviral responses.
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Affiliation(s)
- Safia Deddouche
- Unité Propre de Recherché 9022, Centre National de la Recherche Scientifique, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
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Hermann PM, Nicol JJ, Bulloch AGM, Wildering WC. RGD-dependent mechanisms in the endoneurial phagocyte response and axonal regeneration in the nervous system of the snail Lymnaea stagnalis. ACTA ACUST UNITED AC 2008; 211:491-501. [PMID: 18245625 DOI: 10.1242/jeb.013102] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Activation of phagocytic cells in the injury zone is a crucial step in the regeneration of peripheral axons. Many aspects of the mechanisms underlying the recruitment of active phagocytes remain, however, unclear. Notably, our understanding of the interactions between injury, extracellular matrix (ECM) degradation and phagocyte activation is limited. Most animal cell types, phagocytes included, interact with proteins of the ECM through one or more members of the integrin family, transmembrane cell adhesion receptors that typically bind their ligands through short linear amino acid sequences. This study focused on the role of one of the most common of such integrin recognition sequences, the Arg-Gly-Asp (RGD) motif in the recruitment and activation of endoneurial phagocytes in the injury response of the nervous system of the pond snail Lymnaea stagnalis. Like the mammalian nervous system, the Lymnaea nervous system responds to injury with recruitment and activation of endoneurial phagocytes (i.e. phagocytes residing in Lymnaea's nerves), a process involving substantial changes in the morphology, motility and adhesion status of these cells. Using synthetic water-soluble RGD-peptides, we investigated the relevance of RGD-dependent mechanisms in the activation of endoneurial phagocytes and injury response of the organ-cultured nervous system of Lymnaea. Our results show that RGD-peptides modulate various aspects of phagocyte activation (i.e. spreading response, particle engulfment, oxidative burst) in vitro and in situ and significantly affect nerve regeneration in this model system. Surprisingly, while linear RGD-analogues suppressed both phagocyte activation and axonal regeneration, a circularized RGD-peptide analogue modulated these parameters in a concentration-dependent, biphasic manner. Collectively, these results emphasize the significance of RGD-dependent mechanisms in the regenerative response of the Lymnaea nervous system and implicate regulation of the cellular immune response as one of the factors in this context.
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Affiliation(s)
- Petra M Hermann
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada, T2N 1N4
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Sheldon T, Miguel-Aliaga I, Gould A, Taylor W, Conklin D. A novel family of single VWC-domain proteins in invertebrates. FEBS Lett 2007; 581:5268-74. [DOI: 10.1016/j.febslet.2007.10.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 10/04/2007] [Accepted: 10/10/2007] [Indexed: 11/30/2022]
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Lagadic L, Coutellec MA, Caquet T. Endocrine disruption in aquatic pulmonate molluscs: few evidences, many challenges. ECOTOXICOLOGY (LONDON, ENGLAND) 2007; 16:45-59. [PMID: 17235673 DOI: 10.1007/s10646-006-0114-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
As compared to other groups of aquatic gastropods, documented examples of endocrine disruption in pulmonates are rather limited. This is quite surprising because the endocrine control of physiological functions has been extensively studied in these animals. In the model-species Lymnaea stagnalis, the neurohormonal regulation of reproduction has been thoroughly investigated, and the primary structure of several peptides and receptors involved in endocrine processes has been established. However, the use of this knowledge has been fairly limited in the context of ecotoxicology, to investigate the effects of endocrine-disrupting chemicals. The present review summarizes the main and more recent findings on the neuroendocrine control of reproduction in aquatic pulmonate snails (Basommatophora). It then comprehensively describes selected in vivo laboratory and semi-field studies which provide evidence for possible endocrine disrupting effects of estrogenic and androgenic test compounds [e.g., ethynylestradiol, methyltestosterone (MT)], and of environmental contaminants [e.g., cadmium (Cd), tributyltin (TBT), and nonylphenol (NP), pesticides]. Finally, challenging perspectives for future research are discussed.
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Affiliation(s)
- Laurent Lagadic
- UMR985 INRA-Agrocampus Ecobiologie et Qualité des Hydrosystèmes Continentaux, Equipe Ecotoxicologie et Qualité des Milieux aquatiques, 65 Rue de Saint-Brieuc, F-35042 Rennes Cedex, France.
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Eagan MS, Lyle RM, Gunther CW, Peacock M, Teegarden D. Effect of 1-year dairy product intervention on fat mass in young women: 6-month follow-up. Obesity (Silver Spring) 2006; 14:2242-8. [PMID: 17189552 DOI: 10.1038/oby.2006.263] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Previous results from this laboratory suggest that a 1-year dairy intake intervention in young women does not alter fat mass. The objective of this study was to determine the impact of the 1-year dairy intervention 6 months after completion of the intervention. RESEARCH METHODS AND PROCEDURES Previously, normal-weight young women (n = 154) were randomized to one of three calcium intake groups: control (<800 mg/d), medium dairy (1000 to 1100 mg/d), or high dairy (1300 to 1400 mg/d) for a 1-year trial (n = 135 completed). In the current study, 51 women were assessed 6 months after completion of the intervention trial. Body compositions (body fat, lean mass) were measured using DXA. Self-report questionnaires were utilized to measure activity and dietary intake (kilocalories, calcium). RESULTS The high-dairy group (n = 19) maintained an elevated calcium intake (1027 +/- 380 mg/d) at 18 months compared with the control group (n = 18, 818 +/- 292; p = 0.02). Mean calcium intake over the 18 months predicted a negative change in fat mass (p = 0.04) when baseline BMI was controlled in regression analysis (model R(2) = 0.11). 25-Hydroxyvitamin D levels were correlated with fat mass at each time-point (baseline, r = -0.41, p = 0.003; 12 months, r = -0.42, p = 0.002; 18 months, r = -0.32, p = 0.02) but did not predict changes in fat mass. DISCUSSION Dietary calcium intake over 18 months predicted a negative change in body fat mass. Thus, increased dietary calcium intakes through dairy products may prevent fat mass accumulation in young, healthy, normal-weight women.
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Affiliation(s)
- Marianne S Eagan
- Department of Foods and Nutrition, Purdue University, 1264 Stone Hall, 700 West State Street, West Lafayette, IN 47907, USA
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Walker AJ. Do trematode parasites disrupt defence-cell signalling in their snail hosts? Trends Parasitol 2006; 22:154-9. [PMID: 16488192 DOI: 10.1016/j.pt.2006.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 01/05/2006] [Accepted: 02/06/2006] [Indexed: 11/19/2022]
Abstract
More than a decade ago, it was postulated that components derived from trematode parasites block receptors on the defence cells of their snail intermediate hosts, thus preventing host-cell activation and parasite elimination. This phenomenon has still not been investigated extensively. However, recent work concerning the molecular regulation of the molluscan defence response provides a new framework for studies that focus on an extension of this original concept - subversion of host cell signalling by trematode parasites. The hypothesis is that, to facilitate survival and replication in their intermediate hosts, trematode parasites down regulate host defence responses by interfering with key signal-transduction pathways in snail defence cells.
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Affiliation(s)
- Anthony J Walker
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey, UK, KT1 2EE.
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Abstract
There is a growing understanding of risks posed by human contact with the cercariae of bird schistosomes. In general, there are no fundamental biological differences between human and bird schistosomes in terms of their interactions with snail and vertebrate hosts. The penetration of host surfaces is accompanied by the release of penetration gland products and the shedding of highly antigenic surface components (miracidial ciliated plates and cercarial glycocalyx) which trigger host immune reactions. New surface structures are formed during transformation: the tegument of mother sporocysts and the tegumental double membrane of schistosomula. These surfaces apparently serve as protection against the host immune response. Certain parasite excretory-secretory products may contribute to immunosuppression or, on the other hand, stimulation of host immune reactions. Discovery of new species and their life cycles, the characterization of host-parasite interactions (including at the molecular level), the determination of parasite pathogenicity towards the host, the development of tools for differential diagnosis and the application of protective measures are all topical research streams of the future. Regularly updated information on bird schistosomes and cercarial dermatitis can be found at http://www.schistosomes.cz (web pages of Schistosome Group Prague).
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Affiliation(s)
- P Horák
- Department of Parasitology, Faculty of Science, Charles University, Vinicná 7, CZ-12844 Prague 2, Czech Republic.
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