1,721,175 research outputs found
Aspects of eco-immunology in molluscs.
Full text linkThere is increasing interest in the international scientific community in eco-immunology, a relatively new discipline combining the knowledge from immunology, biology, ecology, physiology and biochemistry. The integrative approach of different scientific disciplines provides a useful perspective, mostly from an evolutionary point of view, into the understanding of the basic mechanisms of the immune responses, as well as the complex host-parasite interactions. However, while knowledge concerning factors affecting the immune response is increasing, more efforts should be made to determine the physiological mechanisms that regulate these responses. This need is particularly pressing in investigations in invertebrates because they are model organisms widely used to study the basic mechanisms of innate immunity and to assess environmental health (the immunomarker approach in biomonitoring studies). In this context, this review focuses on some of the eco-immunology aspects of molluscs
Effects of pharmaceuticals on immune parameters of aquatic invertebrates
No full textPharmaceuticals are a large group of chemicals used either by humans for personal health or by agribusiness to enhance the growth and health of livestock. Pharmaceuticals are considered to be emerging environmental contaminants. Indeed, several studies have shown that these compounds continuously enter aquatic ecosystems. Both pharmaceutical consumption and erroneous discharge of unused or expired medications make notable contributions to the introduction of pharmaceuticals into the environment. Additionally, pharmaceuticals consumed by humans and livestock are not entirely absorbed by organisms and are excreted and passed into wastewater and surface water. Although most pharmaceuticals are designed for human consumption, they can affect non-target organisms that share certain homologous receptors with humans. This review intends to summarise the most recent information concerning the effects of some classes of pharmaceuticals on the immune parameters of aquatic invertebrates
DNA strand breaks in the crab Carcinus aestuarii exposed to three BPA analogues and their mixture
Full text linkIn this study, the genotoxic effects of three different bisphenols (BPAF, BPF and BPS) and their mixture were assessed in the crab Carcinus aestuarii. Crabs were exposed for 7 and 14 days to 300 ng/L of BPA analogues, alone or as a mixture (100 ng/L for each compound). After 7- and 14-day exposure, gills and hepatopancreas were sampled from crabs to evaluate damage to DNA by quantifying the levels of DNA single- and double-strand breaks. Results indicated that BPA analogues increased the DNA damage in both gills and hepatopancreas. In detail, BPAF, the most hydrophobic compound tested, exerted a marked effect on DNA. Overall, results suggest that such relatively new compounds can cause damage to DNA in crabs, raising doubts about the toxicological profile of BPA analogues, at least in the species studied and under the conditions tested in this study
Haemocytes of the cockle Cerastoderma glaucum: cell types and involvement in immune responses.
No full textFor the first time, morpho-functional characterisation of haemocytes from the cockle Cerastoderma glaucum was performed to identify circulating cell types and to study their involvement in immune responses. Haemocyte mean number was 5.5 (x105) cells/ml haemolymph (n=10). Two main haemocyte types were found in haemolymph: granulocytes (85 %), about 10 μm in diameter and with evident cytoplasmic granules, and hyalinocytes (15%), 8 to 14 μm in diameter, with a few or no granules. Most of the cytoplasmic granules stained in vivo with Neutral Red, indicating that they were lysosomes. On the basis of haemocyte staining properties, granulocytes and hyalinocytes were further classified as basophils and acidophils. Acidophil hyalinocytes were the largest haemocyte type (about 14 μm in diameter) and had an eccentric nucleus and a large cytoplasmic vacuole. Both granulocytes and hyalinocytes (except acidophils) were able to phagocytise yeast cells, although the basal phagocytic index was very low (about 2 %). It increased significantly (up to 26 %) after pre-incubation of yeast in cell-free haemolymph, suggesting that haemolymph has opsonising properties. Haemocytes also produced superoxide anion. Moreover, both granulocytes and hyalinocytes (except acidophils) were positive to some important hydrolytic and oxidative enzymes, such as acid phosphatase, non-specific esterase, acid esterase, and peroxidase. Lysozyme-like activity was recorded in both cell-free haemolymph and haemocyte lysate, although enzyme activity in cell lysate was significantly higher. Results indicate that haemocytes from C. glaucum are effective cells in immune responses
Do reproductive conditions influence responsiveness of vitellogenin-like protein induction in clams (Tapes philippinarum) exposed to 4-nonylphenol?
No full textIn a previous study, we demonstrated that exposure
for 7 days of the clam Tapes philippinarum to 4-nonylphenol
(NP) induced vitellogenin (Vg)-like proteins in both
haemolymph and digestive gland of males. The aim of the
present study was to evaluate NP estrogenic potency in
sexually undifferentiated clams. Molluscs were exposed for
7 and 14 days to various sublethal NP concentrations (0,
0+acetone, 0.0125, 0.025, 0.05, 0.1 and 0.2 mg NP/L and
0, 0+acetone, 0.0125, 0.025, 0.05 and 0.1 mg NP/L, respectively)
and Vg-like protein levels were evaluated in
both haemolymph and digestive glands of clams by the
alkali-labile phosphate assay (ALP). Haemolymph Ca2+
levels were also measured, this parameter being considered
strictly related to the presence of Vg-like proteins. Exposure
for 7 days to 0.2 mg NP/L resulted in statistically significant
increases in Vg-like proteins (expressed as μg ALP/
mg protein) in both haemolymph and digestive gland, with
respect to controls. Conversely, haemolymph Ca2+ levels
did not show significant variations. In 14-days treatments,
Vg and Ca2+ levels showed a similar increasing trend in
haemolymph, although significant differences with respect
to controls were found at 0.025 and 0.05 mg NP/L for Ca2+
only. A dose-dependent Vg increase was also observed in
digestive gland, significant at 0.1 mg NP/L. Responsiveness
of Vg induction was confirmed in quiescent clams,
mostly when measured in digestive gland, indicating applicability
of the biomarker throughout the whole reproductive
cycle of animals in both laboratory and field studies.
A relationship between Vg and Ca2+ levels was detected in
prolonged exposure only
The role of haemocytes from the crab Carcinus aestuarii (Crustacea, Decapoda) in immune responses: a first survey.
No full textFor the first time, a functional study of haemocytes from the crab Carcinus aestuarii was performed in order to evaluate their involvement in immune responses. Total haemocyte count (THC), phagocytosis, haemolymph opsonisation properties, hydrolytic and oxidative enzyme activities, and production of intracellular superoxide anion were evaluated. A great variability in THC was recorded among individuals, and haemocyte mean number was 6.4 (x106) cells/ml haemolymph. Although only hyalinocytes were able to phagocytose yeast cells or Zymosan, phagocytic index was low (3%) and did not increase significantly (4%) after pre-incubation of yeast and Zymosan in cell-free haemolymph, suggesting that haemolymph did not have opsonising properties. All haemocyte types produced superoxide anion, whereas only granulocytes were positive to the hydrolytic enzymes assayed. In addition, only granulocytes were positive to phenoloxidase activity. Both Petri dish and spectrophotometric assays revealed a very low lysozyme-like activity in cell-free haemolymph (CFH) and haemocyte lysate (HL), although enzyme activity was higher in CFH than in HL. Interestingly, normalisation of data as to total protein content in CFH and HL resulted in an opposite situation, lysozyme-like activity being higher in HL than in CFH. This demonstrated that haemolymph of C. aestuarii has a high quantity of total proteins, functional properties of which need to be better investigated in future studies. Overall, the results obtained in the present study indicated that C. aestuarii haemocytes are not very active phagocytic cells, but they are more active in terms of both hydrolytic and oxidative enzyme activities and superoxide anion production
Can 4-nonylphenol induce vitellogenin-like proteins in the clam Tapes philippinarum?
No full textVitellogenins (Vg) are precursors of egg-yolk proteins (vitellins) constituting energy reserves for embryos. In oviparous females,
Vg are produced in the liver (or equivalent organs) under the control of endogenous estrogens, released into the bloodstream
(plasma or hemolymph), and stored in developing oocytes. Although Vg levels are generally undetectable in male plasma, they may
significantly increase in (xeno-)estrogen-exposed males. The aim of the present study was to evaluate estrogenic effects of 4-
nonylphenol (NP) in sexually differentiated males and females of the Manila clam Tapes philippinarum. Clams were exposed for 7
days to various sublethal NP concentrations (0, 0+acetone, 0.025, 0.05, 0.1, and 0.2 mgNP/L) and Vg-like protein levels were
evaluated in both hemolymph and digestive glands of mollusks by the alkali-labile phosphate assay. This method, based on the
determination of phosphates released by Vg, has previously been used to detect Vg concentrations in both fish plasma and bivalve
hemolymph. Although Vg levels were generally higher in both hemolymph and digestive gland of T. philippinarum females, males
appeared to be more sensitive than females to the estrogenic effects of NP. In males exposed to 0.1 and 0.2 mg NP/L, Vg levels
increased significantly in both hemolymph (Po0:05 and Po0:01; respectively) and digestive gland (Po0:05), whereas no changes
were observed in those of females. Although the mechanisms by which NP exerts its in vivo endocrine-modulating effects in bivalve
mollusks remain unclear, the results of this study demonstrate that NP may induce Vg-like proteins in T. philippinarum, particularly
males
First evidence of altered vitellogenin-like protein levels in clam Tapes philippinarum and in cockle Cerastoderma glaucum from the Lagoon of Venice.
No full textPossible xenoestrogenic effects were investigated, for the first time, in two bivalve species from the Lagoon of Venice (Italy): the clam
Tapes philippinarum and the cockle Cerastoderma glaucum. Bivalves were collected far from their reproductive phase at the very early
stage of gametogenesis (January), and in the pre-spawning period (June) in six sites. Vitellogenin (Vg)-like proteins (a biomarker of exposure
to estrogenic compounds) were measured by the alkali-labile phosphate method (ALP), in both haemolymph and digestive gland
from males and females (when it was possible to distinguish sex by microscopic observation of gonadal tissue). Haemolymph calcium
concentrations (a parameter considered closely related to the presence of Vg-like proteins) and the bivalve condition index (CI) were also
measured. In both seasons, bivalves collected at Campalto (near a sewage treatment plant) and Marghera (a highly contaminated area)
had higher Vg-like protein levels, particularly in haemolymph, than animals from the other sampling sites. Interestingly, CI had high
values in these polluted sites. In June only, Vg-like proteins and Ca2+ levels in haemolymph exhibited similar trends in both bivalve species
at most sampling sites. The responsiveness of bivalves to environmental xenoestrogens was higher in June, allowing better discrimination
among sites. The present study demonstrates that animals from highly polluted areas have increased Vg-like protein levels. As
endocrine disruption due to exposure to estrogenic compounds may cause fertility reduction, alterations in the sex ratio, and a decrease
in reproductive rate, a condition of potential risk for bivalve populations in estuarine areas is highlighted
Are really males the sterner sex? The immune responses of the clam Tapes philippinarum as a case study
No full textFor the first time, gender-related differences in immune responses of the clam Tapes philippinarum were investigated. Haemocytes from male, female and sexually undifferentiated clams were collected, and total haemocyte count (THC), haemocyte volume, capability of haemocytes to assume the vital dye Neutral Red (indicative of endocytotic activity), acid phosphatase and lysozyme-like activities in both haemocyte lysate (HL) and cell-free haemolymph (CFH), were evaluated.
No statistically significant differences in THC values were observed. However, differing haemocyte size frequency distribution was found: the fraction of larger haemocytes (6-8 μm diameter, 200 fl volume) markedly increased in females, whereas the fraction of smaller haemocytes (< 5 μm diameter, < 200 fl volume) increased in both male and undifferentiated clams. Significantly increased Neutral Red uptake was recorded in haemocytes from females. This was most likely related to the higher fraction of larger haemocytes in females, these cells being more actively involved in phagocytosis. No significant variations in lysozyme-like activity was observed in HL, whereas in CFH enzyme activity resulted significantly higher in females with respect to male and undifferentiated animals. HL acid phosphatase activity was significantly higher in males with respect to females and undifferentiated clams, whereas no significant variations in enzyme activity was observed in CFH. Overall, results obtained demonstrated that gender-
related differences in immune responses occurred in T. philippinarum, and indicated that females had more active haemocytes than both male and undifferentiated clams, at least on the basis of the cellular parameters investigated
Valutazione dei livelli di proteine vitellogenina-like in molluschi bivalvi della Laguna di Venezia.
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