Evolution of the acute phase response: iron release by echinoderm (Asterias forbesi) coelomocytes, and cloning of an echinoderm ferritin molecule

Toxic mechanisms of nanoplastics exposure at environmental concentrations on juvenile red swamp crayfish (Procambarus clarkii): From multiple perspectives

Nanoplastics pollution has emerged as a global issue due to its widespread potential toxicity. This study delved in to toxic effects of nanoplastics on juvenile P. clarkii and molecular mechanisms from perspectives of growth, biochemical, histopathological analysis and transcriptome level for the first time. The findings of this study indicated that nanoplastics of different concentrations have varying influence mechanisms on juvenile P. clarkii. Nanoplastics have inhibitory effects on growth of juvenile P. clarkii, can induce oxidative stress. The biochemical analysis and transcriptome results indicated that 10 mg/L nanoplastics can activate the antioxidant defense system and non-specific immune system in juvenile P. clarkii, and affect energy metabolism and oxidative phosphorylation. While 20 mg/L and 40 mg/L have a destructive influence on the immune function in juvenile P. clarkii, leading to lipid peroxidation and oxidative damage, and induce apoptosis, can affect ion transport and osmotic pressure regulation. The findings of this study can offer foundational data for delving further into impacts of nanoplastics on crustaceans and toxicity mechanism.

Advancements of the Molecular Directed Design and Structure-Activity Relationship of Ferritin Nanocage

Ferritin nanocages possess remarkable structural properties and biological functions, making them highly attractive for applications in functional materials and biomedicine. This comprehensive review presents an overview of the molecular characteristics, extraction and identification of ferritin, ferritin receptors, as well as the advancements in the directional design of high-order assemblies of ferritin and the applications based on its unique structural properties. Specifically, this Review focuses on the regulation of ferritin assembly from one to three dimensions, leveraging the symmetry of ferritin and modifications on key interfaces. Furthermore, it discusses targeted delivery of nutrition and drugs through facile loading and functional modification of ferritin. The aim of this Review is to inspire the design of micro/nano functional materials using ferritin and the development of nanodelivery vehicles for nutritional fortification and disease treatment.

Preparation and Unique Three-Dimensional Self-Assembly Property of Starfish Ferritin

The structure and assembly properties of ferritin derived from aquatic products remain to be explored. Constructing diverse three-dimensional (3D) protein architectures with the same building blocks has important implications for nutrient delivery, medicine and materials science. Herein, ferritin from Asterias forbesii (AfFer) was prepared, and its crystal structure was resolved at 1.91 Å for the first time. Notably, different from the crystal structure of other reported ferritin, AfFer exhibited a BCT lattice arrangement in its crystals. Bioinspired by the crystal structure of AfFer, we described an effective approach for manufacturing 3D porous, crystalline nanoarchitectures by redesigning the shared protein interface involved in different 3D protein arrays. Based on this strategy, two 3D superlattices of body-centered tetragonal and simple cubicwere constructed with ferritin molecules as the building blocks. This study provided a potentially generalizable strategy for constructing different 3D protein-based crystalline biomaterials with the same building blocks.

C-Reactive Protein: Friend or Foe? Phylogeny From Heavy Metals to Modified Lipoproteins and SARS-CoV-2

Animal C-reactive protein (CRP) has a widespread existence throughout phylogeny implying that these proteins have essential functions mandatory to be preserved. About 500 million years of evolution teach us that there is a continuous interplay between emerging antigens and components of innate immunity. The most archaic physiological roles of CRP seem to be detoxication of heavy metals and other chemicals followed or accompanied by an acute phase response and host defense against bacterial, viral as well as parasitic infection. On the other hand, unusual antigens have emerged questioning the black-and-white perception of CRP as being invariably beneficial. Such antigens came along either as autoantigens like excessive tissue-stranded modified lipoprotein due to misdirected food intake linking CRP with atherosclerosis with an as yet open net effect, or as foreign antigens like SARS-CoV-2 inducing an uncontrolled CRP-mediated autoimmune response. The latter two examples impressingly demonstrate that a component of ancient immunity like CRP should not be considered under identical “beneficial” auspices throughout phylogeny but might effect quite the reverse as well.

Crystallographic characterization of a marine invertebrate ferritin from the sea cucumber Apostichopus japonicus

Ferritin is considered to be an ubiquitous and conserved iron-binding protein that plays a crucial role in iron storage, detoxification and immune response. Although ferritin is of critical importance for almost all kingdoms of life, there is a lack of knowledge about its role in the marine invertebrate sea cucumber (Apostichopus japonicus). In this study, we characterized the first crystal structure of Apostichopus japonicas ferritin (AjFER) at 2.75 Å resolution. The structure of AjFER shows a 4-3-2 symmetry cage-like hollow shell composed of 24 subunits, mostly similar to the structural characteristics of other known ferritin species, including the conserved ferroxidase center and 3-fold channel. The 3-fold channel consisting of three 3-fold negative amino acid rings suggests a potential pathway in which metal ions can be first captured by Asp120 from the outside environment, attracted by His116 and Cys128 when entering the channel, and then transferred by Glu138 from the 3-fold channel to the ferroxidase site. Overall, the presented crystal structure of AjFER may provide insights into the potential mechanism of the metal transport pathway for related marine invertebrate ferritins.

Conservative and Atypical Ferritins of Sponges

Ferritins comprise a conservative family of proteins found in all species and play an essential role in resistance to redox stress, immune response, and cell differentiation. Sponges (Porifera) are the oldest Metazoa that show unique plasticity and regenerative potential. Here, we characterize the ferritins of two cold-water sponges using proteomics, spectral microscopy, and bioinformatic analysis. The recently duplicated conservative HdF1a/b and atypical HdF2 genes were found in the Halisarca dujardini genome. Multiple related transcripts of HpF1 were identified in the Halichondria panicea transcriptome. Expression of HdF1a/b was much higher than that of HdF2 in all annual seasons and regulated differently during the sponge dissociation/reaggregation. The presence of the MRE and HRE motifs in the HdF1 and HdF2 promotor regions and the IRE motif in mRNAs of HdF1 and HpF indicates that sponge ferritins expression depends on the cellular iron and oxygen levels. The gel electrophoresis combined with specific staining and mass spectrometry confirmed the presence of ferric ions and ferritins in multi-subunit complexes. The 3D modeling predicts the iron-binding capacity of HdF1 and HpF1 at the ferroxidase center and the absence of iron-binding in atypical HdF2. Interestingly, atypical ferritins lacking iron-binding capacity were found in genomes of many invertebrate species. Their function deserves further research.

Correlation Between Serum Ferritin and Viral Hepatitis in Thalassemia Patients

Serum ferritin is an acute phase protein; importantly, its level is noticeably increased in response to iron overload and systemic inflammation. The iron overload status in thalassemia patients has been recognized as a potential way to measure liver iron concentration (LIC) levels using magnetic resonance imaging (MRI). The aim of this study was to investigate the effect of chronic viral hepatitis on the level of serum ferritin in patients with thalassemia. A cross-sectional study was conducted involving chronic viral hepatitis infection. Mean serum ferritin and LIC levels were recorded. The LIC values were used to divide the patients into two groups; a higher LIC group (>5 mg Fe/g) and a lower LIC group (<5 mg Fe/g). Mean serum ferritin levels were then compared between the two LIC groups. We identified 32 thalassemia patients comprising of 13 chronic viral hepatitis patients, seven patients with hepatitis B virus (HBV), and six patients with hepatitis C virus (HCV). With regard to the group with higher LIC values, the mean serum ferritin levels in the hepatitis group were significantly higher than for those in the non hepatitis group (1776 ± 488 vs. 967 ± 860 ng/mL, p = 0.03). Furthermore, the linear correlation between the mean serum ferritin levels and the viral load in the non transfusion-dependent thalassemia (NTDT) group were found to be significantly correlated (r = 0.7, p = 0.04). Chronic viral hepatitis was determined to be a possible casualty of disproportionately high ferritin levels in the NTDT group.

Identification of proteins in housefly (Musca domestica) larvae powder by LC-MS/MS and their potential medical relevance

Housefly larvae (HL) powder was used to cure wounds centuries ago for its good nutritional and pharmacological values. At present, most of the medical studies are about the crude extracts of HL, while the specific pharmacological material basis is still unclear. We ground third-instar Musca domestica larvae into a powder, degreasing and preparing the protein extract. The protein extract was subjected to enzymatic hydrolysis, and the enzymatic hydrolysis products were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). We identified a variety of highly trusted proteins (false discovery rate is less than or equal to 1%), including catalysis-related proteins, antioxidant proteins and antimicrobial peptides, which may be closely related to the anti-tumor, anti-bacterial, anti-oxidant and other pharmacological effects of HL. We identified the amino acid sequences of these proteins, and further confirmed HL's protective effect on APP/PS1 transgenic Alzheimer's mice. The results of this work provide material basis for further medical research on HL.

Housefly larvae (HL) powder was used to cure wounds centuries ago for its good nutritional and pharmacological values.

A novel ferritin gene from Procambarus clarkii involved in the immune defense against Aeromonas hydrophila infection and inhibits WSSV replication

Ferritin is a protein related to the storage of iron and widely distributed in animals. It participates in many biological process, including antioxidation, cell activation, angiogenesis, regulation of iron metabolic balance and immune defense. In the present study, a novel ferritin gene was identified from red swamp crayfish Procambarus clarkii, with a cDNA sequence encoding a predicted 221 amino-acid residues. The ferritin protein contains a 19-residue signal peptide and 145-residue classic ferritin domain. The NJ phylogenetic analysis showed PcFer clustered with other crustacean peptides. The recombinant PcFer protein was produced and purified in E. coli, and the anti-rabbit polyclonal antibody was obtained. The rPcFer exhibited iron binding activity at a dose-dependent effect. The qPCR and western blot analysis revealed that PcFer was highly expressed in hemocytes, hepatopancreas, and gills. After challenged with WSSV and Aeromonas hydrophila, the mRNA and protein expression patterns of PcFer were significantly up-regulated in hemocytes and hepatopancreas. dsRNA interfering technique was utilized to silence the expression of PcFer gene. The WSSV copy number in PcFer silenced shrimp was much higher than that in the control group. The present study indicated that PcFer was involved in the immune defense against WSSV and Aeromonas hydrophila, and might inhibit WSSV replication in P. clarkii. These results will provide important data support for further study of the functional role of the ferritin gene.

Transcriptional and Translational Relationship in Environmental Stress: RNAseq and ITRAQ Proteomic Analysis Between Sexually Reproducing and Parthenogenetic Females in Moina micrura

Moina micrura is a kind of small-bodied water flea within the family Moinidae. Similar to Daphnia, M. micrura could also switch its reproduction mode from parthenogenetic female (PF) to sexual female (SF) to adapt to the external environment. To uncover the mechanisms of reproductive switching in M. micrura, we used both RNA-Seq and iTRAQ analyses to investigate the differentially expressed genes (DEGs) and their protein products between SF and PF in M. micrura. A total of 1665 DEGs (702 up-regulated, 963 down-regulated) and 600 differentially expressed proteins (DEPs) (102 up-regulated, 498 down-regulated) were detected in SF. Correlation analyses indicated that 31 genes were expressed significantly differentially at both transcriptomic and proteomic levels, including 15 up-regulated genes and 16 down-regulated genes in SF. Meanwhile, our data also showed that 528 DEPs have discordant expression at transcript level, implying post-transcriptional (including translational) regulation. These top up-regulated genes and their protein products in SF were mainly grouped into the globin-related family, vitellogenin-related family, cuticle-related family, Hsp-related family and methyltransferases-related family, which were all involved in the reproductive switching in Daphnia. In contrast, a cluster of orthologous groups revealed that up-regulated genes and their protein products in PF were strongly associated with the metabolic process, which may be responsible for rapid population proliferation in M. micrura.

Hybridization improved bacteria resistance in abalone: Evidence from physiological and molecular responses

Hybridization is an effective way of improving germplasm in abalone, as it often generates benign traits in the hybrids. The hybrids of Haliotis discus hannai and H. gigantea have shown heterosis in terms of disease resistance than one or both parental species. In the present study, to elucidate the physiological and molecular mechanism of this heterosis, we analyzed the dynamic changes of several immune indexes including survival rate, total circulating haemocyte count (THC), phagocytic activity, reactive oxygen species level (ROS) and phenoloxidase activity (PO) in two parental species, H. discus hannai (DD) and H. gigantea (GG), and their reciprocal hybrids H. discus hannai ♀ × H. gigantea ♂ (DG), H. gigantea ♀ × H. discus hannai ♂ (GD) challenged with a mixture of Vibrio harveyi, V. alginolyticus and V. parahaemolyticus (which have been demonstrated to be pathogenic to abalone). Besides, we cloned and analyzed three important immune genes: heat shock protein 70 (hsp70), ferritin and cold shock domain protein (csdp) in H. discus hannai and H. gigantea, then further investigated their mRNA level changes in the four abalone genotypes after bacterial challenge. Results showed that these physiological and molecular parameters were significantly induced by bacterial exposure, and their changing patterns were obviously different between the four genotypes: (1) Survival rates of the two hybrids were higher than both parental species after bacterial exposure; (2) DG had higher THC than the other three genotypes; (3) Phagocytosis responded slower in the hybrids than in the parental species; (4) DD's ROS level was lower than the other three genotypes at 48 h post infection; (5) Phenoloxidase activity was lower in DD during the infection compared to the other genotypes; (6) mRNA levels of hsp70 and csdp, were always lower in at least one parental species (DD) than in the hybrids after the bacterial exposure. Results from this study indicate that the hybrids are more active or efficient in immune system function, hence they could effectively defense against a bacterial invasion, leading to higher survival rates after challenge. This study provides physiological and molecular evidences for interpreting the disease resistant heterosis in this abalone hybrid system, which could help us in a better understanding and utilization of heterosis in abalone aquaculture.

Cytotoxic activity of Holothuria tubulosa (Echinodermata) coelomocytes

The immune system of marine invertebrates, in particular that of holothurians, still requires further study. Our research showed that coelomocyte cells contained in the coelomic fluid of the sea cucumber, Holothuria tubulosa, are able to lyse, in vitro, red blood cells in rabbits and sheep. A plaque-forming assay showed spherule cells to be the effector cells, able to release cytotoxic molecules after xenogenic cell contact. The coelomocyte lysate supernatant, analysed by polyacrylamide gel electrophoresis overlay technique, using rabbit and sheep erythrocytes, showed two different haemolytic protein patterns: one calcium dependent and the other calcium independent. The fractions of each pattern were resolved on a polyacrylamide gel and calcium-dependent and independent coelomocyte lysate patterns were compared.

Lipocalin 2: An Emerging Player in Iron Homeostasis and Inflammation

Lipocalin 2 (Lcn2), an innate immune protein, has emerged as a critical iron regulatory protein during physiological and inflammatory conditions. As a bacteriostatic factor, Lcn2 obstructs the siderophore iron-acquiring strategy of bacteria and thus inhibits bacterial growth. As part of host nutritional immunity, Lcn2 facilitates systemic, cellular, and mucosal hypoferremia during inflammation, in addition to stabilizing the siderophore-bound labile iron pool. In this review, we summarize recent advances in understanding the interaction between Lcn2 and iron, and its effects in various inflammatory diseases. Lcn2 exerts mostly a protective role in infectious and inflammatory bowel diseases, whereas both beneficial and detrimental functions have been documented in neurodegenerative diseases, metabolic syndrome, renal disorders, skin disorders, and cancer. Further animal and clinical studies are necessary to unveil the multifaceted roles of Lcn2 in iron dysregulation during inflammation and to explore its therapeutic potential for treating inflammatory diseases.

Role of histamine in the regulation of intestinal immunity in fish

In mammals, during the acute inflammatory response, the complex interrelationship and cross-talk among histamine and the immune system has been fairly well characterized. There is a substantial body of information on its structure, metabolism, receptors, signal transduction, physiologic and pathologic effects. However, for early vertebrates, there is little such knowledge. In the case of teleost fish, this lack of knowledge has been due to the widely held belief that histamine is not present in this phylogenetic group. However, it has been recently demonstrated, that granules of mast cells in perciforms contain biologically active histamine. More importantly, the inflammatory response was clearly demonstrated to be regulated by the direct action of histamine on professional phagocytes. Nevertheless, the molecular basis and exact role of this biogenic amine in perciforms is still a matter of speculation. Therefore, this review intends to summarize recent experimental evidence regarding fish mast cells and correlate the same with their mammalian counterparts to establish the possible role of histamine in the fish intestinal inflammatory response.

Computational characterization of Iron metabolism in the Tsetse disease vector, Glossina morsitans: IRE stem-loops

Background

Iron metabolism and regulation is an indispensable part of species survival, most importantly for blood feeding insects. Iron regulatory proteins are central regulators of iron homeostasis, whose binding to iron response element (IRE) stem-loop structures within the UTRs of genes regulate expression at the post-transcriptional level. Despite the extensive literature on the mechanism of iron regulation in human, less attention has been given to insect and more specifically the blood feeding insects, where research has mainly focused on the characterization of ferritin and transferrin. We thus, examined the mechanism of iron homeostasis through a genome-wide computational identification of IREs and other enriched motifs in the UTRs of Glossina morsitans with the view to identify new IRE-regulated genes.

Results

We identified 150 genes, of which two are known to contain IREs, namely the ferritin heavy chain and the MRCK-alpha. The remainder of the identified genes is considered novel including 20 hypothetical proteins, for which an iron-regulatory mechanism of action was inferred. Forty-three genes were found with IRE-signatures of regulation in two or more insects, while 46 were only found to be IRE-regulated in two species. Notably 39 % of the identified genes exclusively shared IRE-signatures in other Glossina species, which are potentially Glossina-specific adaptive measures in addressing its unique reproductive biology and blood meal-induced iron overload. In line with previous findings, we found no evidence pertaining to an IRE regulation of Transferrin, which highlight the importance of ferritin heavy chain and the other proposed transporters in the tsetse fly. In the context of iron-sequestration, key players of tsetse immune defence against trypanosomes have been introduced namely 14 stress and immune response genes, while 28 cell-envelop, transport, and binding genes were assigned a putative role in iron trafficking. Additionally, we identified and annotated enriched motifs in the UTRs of the putative IRE-regulated genes to derive at a co-regulatory network that maintains iron homeostasis in tsetse flies. Three putative microRNA-binding sites namely Gy-box, Brd-box and K-box motifs were identified among the regulatory motifs, enriched in the UTRs of the putative IRE-regulated genes.

Conclusion

Beyond our current view of iron metabolism in insects, with ferritin and transferrin as its key players, this study provides a comprehensive catalogue of genes with possible roles in the acquisition; transport and storage of iron hence iron homeostasis in the tsetse fly.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2932-7) contains supplementary material, which is available to authorized users.

Iron metabolism following intravenous transfusion with stored versus fresh autologous erythrocyte concentrate in healthy dogs

OBJECTIVE To determine effects of IV transfusion with fresh (3-day-old) or stored (35-day-old) autologous erythrocyte concentrate on serum labile iron concentration, iron-binding capacity, and protein interaction with iron in dogs. ANIMALS 10 random-source healthy dogs. PROCEDURES Dogs were randomly assigned to receive autologous erythrocyte concentrate stored for 3 days (n = 5) or 35 days (5). One unit of whole blood was collected from each dog, and erythrocyte concentrates were prepared and stored as assigned. After erythrocyte storage, IV transfusion was performed, with dogs receiving their own erythrocyte concentrate. Blood samples were collected from each dog before and 5, 9, 24, 48, and 72 hours after transfusion. Serum was harvested for measurement of total iron, labile iron, transferrin, ferritin, hemoglobin, and haptoglobin concentrations. RESULTS For dogs that received fresh erythrocytes, serum concentrations of the various analytes largely remained unchanged after transfusion. For dogs that received stored erythrocytes, serum concentrations of total iron, labile iron, hemoglobin, and ferritin increased markedly and serum concentrations of transferrin and haptoglobin decreased after transfusion. CONCLUSIONS AND CLINICAL RELEVANCE Transfusion with autologous erythrocyte concentrate stored for 35 days resulted in evidence of intravascular hemolysis in healthy dogs. The associated marked increases in circulating concentrations of free iron and hemoglobin have the potential to adversely affect transfusion recipients.

Identification and involvement of ferritin in the response to pathogen challenge in the abalone, Haliotis diversicolor

Accumulating data has demonstrated that ferritin plays an important role in host defense responses against infection by pathogens in many organisms. In this study, ultracentrifugation was used to isolate ferritin from abalone, Haliotis diversicolor, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that this ferritin consisted of two subunits (designated as HdFer1 and HdFer2). There are no disulfide bonds between the HdFer1 and HdFer2 subunits; however, these subunits co-assemble to form heteropolymers. A novel ferritin subunit (HdFer2) was cloned from H. diversicolor by 5' and 3' RACE (rapid amplification of cDNA ends) approach. The full-length HdFer2 cDNA sequence consists of 878 bp with an open reading frame of 513 bp that encodes a protein that is 170 amino acids in length. Quantitative real-time PCR analysis revealed that HdFer1 and HdFer2 were transcribed in various tissues, such as the mantle, gill and hepatopancreas, with the highest levels of expression in the hepatopancreas. Following a challenge with the pathogen, Vibrio harveyi, the expression of HdFer1 and HdFer2 were markedly induced at different times. This study has identified a novel ferritin subunit in H. diversicolor which will contribute to further exploration of the role of ferritin in mollusk innate immune defense against invading pathogens.

Ferritin has an important immune function in the ark shell Scapharca broughtonii

Ferritin, the principle cytosolic iron storage protein in the majority of living organisms, has important roles during immune process in invertebrates. Detailed information about ferritin in the ark shell Scapharca broughtonii, however, has been very limited. In this study, full-length ferritin (termed SbFer) was cloned by the rapid amplication of cDNA ends (RACE) method based upon the sequence from the transcriptome library. The cDNA contained a 182 bp 5'-untranslated region, a 519 bp open reading frame encoding a polypeptide of 172 amino acids, a 229 bp 3'-untranslated region, and three introns (902, 373 and 402 bp) embedded in four exons. There was an iron response element (IRE) in the 5'-untranslated region. The deduced amino acid sequence of SbFer possessed many characteristics of vertebrate H type ferritin, shared 63%-91% identity with mollusks and greater identity with vertebrate H type ferritin compared to the L type. The SbFer gene expression pattern examined by quantitative real-time PCR showed ferritin mRNA was expressed in all ark shell tissues examined. The highest levels of expression were found in hemocytes with decreasing levels of expression in foot, mantle, gill, adductor muscle and hepatopancreas. A challenge with Vibrio anguillarum resulted in time-dependent significant upregulation of SbFer mRNA, indicating SbFer participated actively in the bacterial defense process. Further analysis of the antibacterial activity indicated recombinant SbFer could function as an immune antibacterial agent to both Gram-positive and Gram-negative bacteria. Taken together, these results suggested strongly that ferritin of the ark shell is involved in immune defense against microbial infection and it is a constitutive and inducible acute-phase protein.

Proteomic characterization of mucosal secretions in the eastern oyster, Crassostrea virginica

The soft body surface of marine invertebrates is covered by a layer of mucus, a slippery gel secreted by mucocytes lining epithelia. The functions of this gel are diverse including locomotion, cleansing, food particles processing and defense against physicochemical injuries and infectious agents. In oysters, mucus covering pallial organs has been demonstrated to have a major importance in the processing of food particles and in the interactions with waterborne pathogens. Given the limited information available on mucus in bivalves and the apparent wide spectra of activity of bioactive molecules present in this matrix, the characterization of these mucosal secretions has become a research priority. In this study, mucus was separately collected from the mantle, gills and labial palps of the eastern oyster (Crassostrea virginica) and analyzed by liquid chromatography and tandem mass spectrometry. Results showed the presence of a wide variety of molecules involved in host-microbe interactions, including putative adhesion molecules (e.g. c-type lectins) confirming that transcripts previously identified in epithelial cells are translated into proteins secreted in mucus. Mucus composition was different among samples collected from different organs. These results generate a reference map for C. virginica pallial mucus to better characterize the various physiological functions of mucosal secretions.

Lectin-Based Profiling of Coelomocytes in Holothuria scabra and Expression of Superoxide Dismutase in Purified Coelomocytes

Coelomocytes are the first line of immune defense in marine animals. Their distributions are greatly variable even in the close animal species. In this study, we used lectin staining to aid in the classification and purification of these cells for further investigation of SOD distribution among coelomocytes of H. scraba. We classified coelomocytes into four types: type 1, lymphocytes; type 2, phagocytes; type 3, spherulocytes; and type 4, giant cells. Among four lectins used, Con A appeared to give a broad reactivity against most coelomocytes, except for giant cells. In addition, phagocytes usually engaged the highest fluorescent intensity with most lectins, with the exception of PNA, for which spherulocytes possessed the highest fluorescent intensity. Using FACS for fraction collection, it was found that F1 fraction contained the purest phagocyte population (> 95%), which was highly reactive with anti- superoxide dismutase (SOD) as revealed by immunoblotting and immunofluorescence staining, although some minor staining was also detected in spherulocytes. Our results thus provide a fundamental platform for comparing alterations that may happen to the population and SOD contents of coelomocytes when the sea cucumber is subjected to environmental changes that would activate their immune responses.

The early stages of the immune response of the European abalone Haliotis tuberculata to a Vibrio harveyi infection

Vibrio harveyi is a marine bacterial pathogen responsible for episodic abalone mortalities in France, Japan and Australia. In the European abalone, V. harveyi invades the circulatory system in a few hours after exposure and is lethal after 2 days of infection. In this study, we investigated the responses of European abalone immune cells over the first 24 h of infection. Results revealed an initial induction of immune gene expression including Rel/NF-kB, Mpeg and Clathrin. It is rapidly followed by a significant immuno-suppression characterized by reduced cellular hemocyte parameters, immune response gene expressions and enzymatic activities. Interestingly, Ferritin was overexpressed after 24 h of infection suggesting that abalone attempt to counter V. harveyi infection using soluble effectors. Immune function alteration was positively correlated with V. harveyi concentration. This study provides the evidence that V. harveyi has a hemolytic activity and an immuno-suppressive effect in the European abalone.

Serum Ferritin as A Marker for Preterm Premature Rupture of Membranes -A Study From A Tertiary Centre in Central Kerala

BACKGROUND

Preterm birth is the leading cause of newborn deaths and also the leading cause of death in children under 5 years of age. There is wide spread suspicion that subclinical infection is a common accompaniment and cause of preterm labour. Ferritin is an acute phase reactant and it increases during inflammation.This study aims to determine whether serum ferritin levels which may be raised in the setting of any infective process could be used as a marker of spontaneous preterm labour or PPROM (Preterm premature rupture of membranes).

AIM

To determine whether serum ferritin levels, which may be raised in the setting of any infective process, could be used as a marker of spontaneous preterm labour or PPROM.

STUDY SETTING

Department of Obstetrics and Department of Biochemistry.

STUDY DESIGN

Descriptive comparative design.

MATERIALS AND METHODS

The study involved 3 groups. 50 patients of PPROM, 50 patients of spontaneous preterm labour and 50 pregnant women matching with haemoglobin and same gestational age Serum ferritin were analysed in all the 3 groups.

STATISTICAL ANALYSIS

Significance of difference in the means of serum ferritin levels between the pregnant women (preterm) in the 3 groups were found out using ANOVA and also using a post hoc test (Tukey test). A p-value of < 0.05 was considered significant.

RESULTS

There was a significant increase in serum ferritin in PPROM cases as compared to the control group. But no significant increase in spontaneous preterm labour cases as compared to the control group.

CONCLUSION

Serum ferittin can be used as a marker of PPROM but cannot be used as a marker for spontaneous preterm labour. A cut off value of 35.5 mg/l of serum ferritin may be used for predicting PPROM cases.

Nanosilver pathophysiology in earthworms: Transcriptional profiling of secretory proteins and the implication for the protein corona

Previously we have identified lysenin as a key protein constituent of the secretome from Eisenia fetida coelomocytes and revealed its critical importance in priming interactions between the cells and the protein corona around nanosilver. As alterations of the protein environment can directly affect the corona composition, the extent to which nanoparticles influence the cells' protein secretion profile is of remarkable interest that has rarely acquired attention. Here, we have probed transcriptional responses of E. fetida coelomocytes to the representative nanosilver NM-300K (15 nm) in a time-dependent manner (2, 4, 8 and 24 h at a low-cytotoxic concentration), and examined the implication of the temporal changes in transcriptional profiles of secretory proteins with a particular reference to that of lysenin. NM-300K was accumulated in/at the cells and lysenin was, after transient induction, gradually suppressed over time indicating a negative feedback cycle. This may limit further enrichment of lysenin in the corona and thereby decrease the lysenin-assisted uptake of the nanoparticles. Other differentially expressed genes were those involved in metal stress (likewise in AgNO3-stressed cells) and in Toll-like receptor (TLR) signaling. This offers an intriguing perspective of the nanosilver pathophysiology in earthworms, in which the conserved pattern recognition receptor TLRs may play an effector role.

Toxicological responses of the hard clam Meretrix meretrix exposed to excess dissolved iron or challenged by Vibrio parahaemolyticus

The responses of genes encoding defense components such as ferritin, the lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF), the inhibitor of nuclear factor-κB (IκB), metallothionein, and glutathione peroxidase were assessed at the transcriptional level in order to investigate the toxicological and immune mechanism of the hard clam Meretrix meretrix (HCMM) following challenge with iron or a bacterium (Vibrio parahaemolyticus). Fe dissolved in natural seawater led to an increase of Fe content in both the hepatopancreas and gill tissue of HCMM between 4 and 15 days of exposure. The ferritin gene responded both transcriptionally as indicated by real-time quantitative PCR and translationally as shown by western blotting results to iron exposure and both transcriptional and translational ferritin expression in the hepatopancreas had a positive correlation with the concentration of dissolved iron in seawater. Both iron and V. parahaemolyticus exposure triggered immune responses with similar trends in clam tissues. There was a significant post-challenge mRNA expression of LITAF and IκB at 3h, ferritin at 24h, and metallothionein and glutathione peroxidase at 48h. This behavior might be linked to their specific functions in physiological processes. These results suggested that similar signaling pathways were triggered during both iron and V. parahaemolyticus challenges. Here, we indicated that the ferritin of Meretrix meretrix was an intermediate in the pathway of iron homeostasis and in its innate immune defense mechanism.

Identification and characterization of a Macrobrachium nipponense ferritin subunit regulated by iron ion and pathogen challenge

Ferritin, a major iron storage protein in most living organisms, plays a crucial role in iron metabolism. In this study, the ferritin subunit MnFer was identified in the oriental river prawn (Macrobrachium nipponense) and functionally characterized. The full-length cDNA of MnFer is 999 bp in size with a 122-bp 5'-untranslated region (UTR), a 364-bp 3'-UTR and a 513-bp open reading frame that encodes a protein possessing 171 amino acids and a deduced molecular weight of 19.40 kDa. Prawn ferritin transcripts are expressed in muscle, heart, hepatopancreas, gill, hemocytes, ovary and testis. Quantitative real-time PCR revealed that the abundance of ferritin transcript was highest in the hepatopancreas followed by muscle. Ferritin transcript expression in muscle increased six-fold 3 h after the injection of iron. In the gill, a four-fold increase in ferritin transcript expression was detected 3 h post-injection; the expression remained elevated for 48 h. Heart ferritin mRNA expression increased up to seven-fold at 24 h post-injection. No significant difference was found in the hepatopancreas. The iron binding capacity of recombinant ferritin protein was also demonstrated in this study. In hemocyte experiments, the transcriptional expression of MnFer showed the strongest response to Aeromonas hydrophila. As a whole, our study suggested that the ferritin from M. nipponense may play critical roles in cellular and organismic iron homeostasis along with in innate immune defense.

The ins and outs of bacterial iron metabolism

Iron is a critical nutrient for the growth and survival of most bacterial species. Accordingly, much attention has been paid to the mechanisms by which host organisms sequester iron from invading bacteria and how bacteria acquire iron from their environment. However, under oxidative stress conditions such as those encountered within phagocytic cells during the host immune response, iron is released from proteins and can act as a catalyst for Fenton chemistry to produce cytotoxic reactive oxygen species. The transitory efflux of free intracellular iron may be beneficial to bacteria under such conditions. The recent discovery of putative iron efflux transporters in Salmonella enterica serovar Typhimurium is discussed in the context of cellular iron homeostasis.

Identification and functional characterization of a novel ferritin subunit from the tropical sea cucumber, Stichopus monotuberculatus

Ferritin is one of the major non-harm iron storage proteins that found in most cell types of animals, plants and microorganisms. In this study, a ferritin subunit named StmFer was identified from the sea cucumber (Stichopus monotuberculatus) and characterized functionally. The full-length cDNA of StmFer is 1184 bp in size with a 5'-untranslated region (UTR) of 131 bp, a 3'-UTR of 531 bp and an open reading frame of 522 bp that encoding a protein of 173 amino acids with a deduced molecular weight of 19.95 kDa. StmFer possesses both the ferroxidase center of vertebrate ferritin heavy subunit and iron nucleation sites of vertebrate ferritin light subunit. For the gene structure, StmFer contains only three exons separated by two introns. Higher levels of mRNA expression were noticed in intestine and coelomocyte of S. monotuberculatus by northern blot analysis. In in vitro experiments performed in coelomocytes, transcriptional expression of StmFer showed the strongest response to polyriboinosinic polyribocytidylic acid [Poly (I:C)] (9.08 fold up-regulation), followed by lipopolysaccharides (LPS), ferrous chloride (FeCl2) and inactivated bacteria (Vibrio alginolyticus) (7.84, 7.41 and 4.90 fold up-regulation, respectively) after 3 h post-challenge. In addition, the anti-oxidation activity and iron binding capacity of recombinant ferritin protein were demonstrated in this study. As a whole, our study suggested that the ferritin from sea cucumber may play critical roles not only in the cellular and organismic iron homeostasis, but also in the innate immune defense.

Gene expression responses to Riemerella anatipestifer infection in the liver of ducks

Riemerella anatipestifer is one of the most economically important pathogens of farm ducks worldwide. The molecular mechanisms that underlie its pathogenesis, particularly the host response to R. anatipestifer infection, are poorly understood. The differentially expressed gene profile of duck livers at 24 h following R. anatipestifer infection was therefore investigated using suppression subtractive hybridizaton analysis. A total of 45 differentially expressed genes were identified, which primarily included genes for proteins involved in acute-phase response, inflammatory response, immune response, wound healing and iron homeostasis. For the expression level of 20 genes from those 45 analysed by quantitative reverse transcriptase-polymerase chain reaction at 8, 24 and 48 h post infection, significant differences were observed among the three time points of measurements. The result from this study revealed a gene expression profile of duck liver during R. anatipestifer infection, and those genes with a role in the immune response and wound healing deserving further investigation to elucidate their respective roles during infection.

Differential expression of genes involved in immunity and biomineralization during Brown Ring Disease development and shell repair in the Manila clam, Ruditapes philippinarum

Severe drop in Manila clams production in French aquacultured fields since the end of the 1980's is associated to Brown Ring Disease (BRD). This disease, caused by the bacteria Vibrio tapetis, is characterized by specific symptoms on the inner face of the shell. Diseased animals develop conchiolin deposit to enrobe bacteria and form new calcified layers on the shell. Suppression subtractive hybridization was performed to identify genes differentially expressed during the early interaction of V. tapetis and Ruditapes philippinarum. Results revealed 301 unique genes differentially expressed during V. tapetis challenge. Several candidates involved in immune and biomineralization processes were selected from libraries. Transcriptional expression of selected candidates was determined in hemolymph and mantle tissues and revealed spatial and temporal variations. At 56 days after infection, when clams were in phase of shell repair, transcripts of galectin and ferritin in hemocytes showed higher expression. Ca-like and serpin transcripts were specifically expressed in mantle and could contribute to defense against BRD.

Shotgun proteomics of coelomic fluid from the purple sea urchin, Strongylocentrotus purpuratus

The purple sea urchin has a complex immune system that is likely mediated by gene expression in coelomocytes (blood cells). A broad array of potential immune receptors and immune response proteins has been deduced from their gene models. Here we use shotgun mass spectrometry to describe 307 proteins with possible immune function in sea urchins including proteins involved in the complement pathway and numerous SRCRs. The relative abundance of dual oxidase 1, ceruloplasmin, ferritin and transferrin suggests the production of reactive oxygen species in coelomocytes and the sequestration of iron. Proteins such as selectin, cadherin, talin, galectin, amassin and the Von Willebrand factor may be involved in generating a strong clotting reaction. Cell signaling proteins include a guanine nucleotide binding protein, the Rho GDP dissociation factor, calcium storage molecules and a variety of lipoproteins. However, based on this dataset, the expression of TLRs, NLRs and fibrinogen domain containing proteins in coelomic fluid and coelomocytes could not be verified.

Molecular properties and immune defense of two ferritin subunits from freshwater pearl mussel, Hyriopsis schlegelii

Ferritin is a conserved iron-binding protein involved in cellular iron metabolism and host defense. In the present study, two distinct cDNAs for ferritins in the freshwater pearl mussel Hyriopsis schlegelii were identified (designated as HsFer-1 and HsFer-2) by SMART RACE approach and expressed sequence tag (EST) analysis. The full-length cDNAs of HsFer-1 and HsFer-2 were of 760 and 877 bp, respectively. Both of the two cDNAs contained an open reading frame (ORF) of 522 bp encoding for 174 amino acid residues. Sequence characterization and homology alignment indicated that HsFer-1 and HsFer-2 had higher similarity to H-type subunit of vertebrate ferritins than L-type subunit. Analysis of the HsFer-1 and HsFer-2 untranslated regions (UTR) showed that both of them had an iron response element (IRE) in the 5'-UTR, which was considered to be the binding site for iron regulatory protein (IRP). Quantitative real-time PCR (qPCR) assays were employed to examine the mRNA expression profiles. Under normal physiological conditions, the expression level of both HsFer-1 and HsFer-2 mRNA were the highest in hepatopancreas, moderate in gonad, axe foot, intestine, kidney, heart, gill, adductor muscle and mantle, the lowest in hemocytes. After stimulation with bacteria Aeromonas hydrophila, HsFer-1 mRNA experienced a different degree of increase in the tissues of hepatopancreas, gonad and hemocytes, the peak level was 2.47-fold, 9.59-fold and 1.37-fold, respectively. Comparatively, HsFer-2 showed up-regulation in gonad but down-regulation in hepatopancreas and hemocytes. Varying expression patterns indicate that two types of ferritins in H. schlegelii might play different roles in response to bacterial challenge. Further bacteriostatic analysis showed that both the purified recombinant ferritins inhibited the growth of A. hydrophila to a certain degree. Collectively, our results suggest that HsFer-1 and HsFer-2 are likely to be functional proteins involved in immune defense against bacterial infection.

Identification of genes differentially expressed in clams Ruditapes philippinarum in response to endosulfan after different exposure time

This study reports molecular biomarkers potentially associated with resistance or sensitivity to the impact of endosulfan in clams, Ruditapes philippinarum. Genomic analysis was made applying suppression subtractive hybridization (SSH) to identify genes up- and down-regulated in calms exposed to 0.5 μg/L endosulfan for 1d and 10d. Results obtained from the SSH library revealed 360 different sequences regulated by endosulfan, which correspond to nine major physiological functions. To validate the expression profiles from SSH, 13 genes regulated by endosulfan were measured by quantitative real-time PCR. This study provides information for the characterization of potential molecular biomarker that may be used in future environmental monitoring and to investigate the mechanisms of stress to endosulfan in clams/marine invertebrates.

Proteomic analysis of liver development of lean Pekin duck (Anas platyrhynchos domestica)

The liver plays vital roles in digestion, metabolism and immune defense. To elucidate the molecular mechanism of nutrient metabolism and antioxidation of lean Pekin duck liver from hatching to slaughter, the proteome changes were investigated using 2-DE, MS, quantitative real-time PCR and bioinformatics. A total of 59 differentially expressed proteins were identified. Proteins involved in transportation were highly up-regulated in newborn ducks whereas 37 proteins associated with metabolism, defense and antioxidation were up-regulated in adult ducks. The over-expression of proteins at the last developmental stage presumably occurs to fulfill the needs of multiple functions of the liver. However, the over-expressed proteins related to transportation during the first developmental stage are involved in maintaining the high basal metabolism of newborn ducks. The functional enrichment analysis also confirmed these results. Furthermore, the protein interaction network predicted 28 proteins acting as key nodes for liver development. The validated expression between proteins and genes provides us target genes for future genetic analyses to improve the health and performance of these ducks. These significant advanced proteome data expand our knowledge on the physiology of the duck liver, thereby providing a potentially valuable foundation for molecular breeding to enhance feed efficiency and immunity and for optimizing the feeding strategy.

New insights in flat oyster Ostrea edulis resistance against the parasite Bonamia ostreae

Bonamiosis due to the parasite Bonamia ostreae has been associated with massive mortality in flat oyster stocks in Europe. Control of the disease currently relies on disease management practices and transfer restriction. Previously, massal selections based on survival to challenge to infection with B. ostreae have been applied to produce flat oyster families with resistant progeny. In an attempt to understand the molecular mechanisms involved in disease resistance, differentially expressed sequence tags between resistant and wild Ostrea edulis haemocytes, both infected with the parasite, were identified using suppression subtractive hybridisation. Expression of seven ESTs has been studied using quantitative reverse-transcriptase PCR. The base-line expression of an extracellular superoxide dismutase, inhibitor of apoptosis (OeIAP), Fas ligand (OeFas-ligand) and Cathepsin B was significantly increased, whilst cyclophilin B appeared significantly decreased in resistant oysters. Considering their great interest for further studies, the open reading frames of the OeFas-ligand and OeIAP were completely sequenced.

Differential immune response in the hard clam (mercenaria mercenaria) against bacteria and the protistan pathogen QPX (quahog parasite unknown)

The immune response of the hard clam (quahog) Mercenaria mercenaria following challenge with live bacteria (Vibrio alginolyticus) and the protist QPX (Quahog Parasite Unknown) was investigated. The study also compared immune responses following QPX challenge in two different hard clam broodstocks exhibiting different degrees of susceptibility toward this parasite. Different immune and stress-related cellular and humoral factors were assessed including general hemocyte parameters (total and differential hemocyte counts, percentage of dead cells, reactive oxygen production, phagocytosis), parameters geared toward QPX (anti-QPX activity in plasma and hemocyte resistance to the cytotoxicity of QPX extracellular products). Two genes (ferritin and metallothionein) previously shown to be modulated following QPX exposure were molecularly characterized by rapid amplification of cDNA ends (RACE) and their transcription levels were determined in resistant and susceptible clams in response to QPX and bacterial challenge. Results indicated that both V. alginolyticus and QPX challenge triggered significant immune responses in clams with similar trends for most measured parameters. However, specific responses were observed for anti-QPX activity in plasma and hemocyte resistance to QPX products as well as ferritin and metallothionein expression according to each inoculum. Similarly, different response patterns were detected following QPX challenge in susceptible and resistant clam stocks. Resistant clams were able to elicit effective response against the parasite leading to the elimination of QPX and the restoration of constitutive immune status whereas QPX-susceptible clams triggered a strong immune modulation characterized by an acute phase response and associated acute phase protein but appeared to be less active in eliminating the parasite. These results suggest that different signaling pathways are triggered during V. alginolyticus and QPX challenge. Moreover, differences in the immune response toward QPX might be linked to the susceptibility or resistance of different clam stocks to the infection by this parasite.

The sialotranscriptome of Antricola delacruzi female ticks is compatible with non-hematophagous behavior and an alternative source of food

The hosts for Antricola delacruzi ticks are insectivorous, cave-dwelling bats on which only larvae are found. The mouthparts of nymphal and adult A. delacruzi are compatible with scavenging feeding because the hypostome is small and toothless. How a single blood meal of a larva provides energy for several molts as well as for oviposition by females is not known. Adults of A. delacruzi possibly feed upon an unknown food source in bat guano, a substrate on which nymphal and adult stages are always found. Guano produced by insectivorous bats contains twice the amount of protein and 60 times the amount of iron as beef. In addition, bacteria and chitin-rich fungi proliferate on guano. Comparative data on the transcriptome of the salivary glands of A. delacruzi is nonexistent and would help to understand the physiological adaptations of salivary glands that accompany different sources of food as well as the steps taken by the Acari toward haematophagy, believed to have evolved from scavenging dead animals. Annotation of the transcriptome of salivary glands from female instars of A. delacruzi collected on guano categorized 5.7% of the clusters of expressed genes as putative secreted proteins. They included abundantly expressed TIL-domain-containing proteins (possible anti-microbials), an abundantly expressed protein similar to a serum amyloid found in the sialotranscriptomes of Ornithodoros spp., a savignygrin, a family of mucin/peritrophin/cuticle-like proteins, anti-microbials and an HIV envelope-like glycoprotein also found in soft ticks. When comparing the transcriptome of A. delacruzi with those of blood-feeding female soft and hard ticks some notable differences were observed; they consisted of the following transcripts over- or under-represented or absent in the sialotranscriptome of A. delacruzi that may reflect its source of food: ferritin, mucins with chitin-binding domains and TIL-domain-containing proteins versus lipocalins, basic tail proteins, metalloproteases, glycine-rich proteins and Kunitz protease inhibitors, respectively.

Three ferritin subunits involved in immune defense from bay scallop Argopecten irradians

Ferritin is a ubiquitous protein that plays an important role in iron storage and iron-withholding strategy of innate immunity. In this study, three genes encoding different ferritin subunits were cloned from bay scallop Argopecten irradians (AiFer1, AiFer2 and AiFer3) by rapid amplification of cDNA ends (RACE) approaches based on the known ESTs. The open reading frames of the three ferritins are of 516 bp, 522 bp and 519 bp, encoding 171,173 and 172 amino acids, respectively. All the AiFers contain a putative Iron Regulatory Element (IRE) in their 5'-untranslated regions. The deduced amino acid sequences of AiFers possess both the ferroxidase center of mammalian H ferritin and the iron nucleation site of mammalian L ferritin. Gene structure study revealed two distinct structured genes encoding a ferritin subunit (AiFer3). Quantitative real-time PCR analysis indicated the significant up-regulation of AiFers in hemocytes after challenged with Listonella anguillarum, though the magnitudes of AiFer1 and AiFer2 were much higher than that of AiFer3. Taken together, these results suggest that AiFers are likely to play roles in both iron storage and innate immune defense against microbial infections.

Hepcidin and iron homeostasis

Despite fluctuations in dietary iron intake and intermittent losses through bleeding, the plasma iron concentrations in humans remain stable at 10-30 μM. While most of the iron entering blood plasma comes from recycling, appropriate amount of iron is absorbed from the diet to compensate for losses and maintain nontoxic amounts in stores. Plasma iron concentration and iron distribution are similarly regulated in laboratory rodents. The hepatic peptide hepcidin was identified as the systemic iron-regulatory hormone. In the efferent arc, hepcidin regulates intestinal iron absorption, plasma iron concentrations, and tissue iron distribution by inducing degradation of its receptor, the cellular iron exporter ferroportin. Ferroportin exports iron into plasma from absorptive enterocytes, from macrophages that recycle the iron of senescent erythrocytes, and from hepatocytes that store iron. In the more complex and less well understood afferent arc, hepatic hepcidin synthesis is transcriptionally regulated by extracellular and intracellular iron concentrations through a molecular complex of bone morphogenetic protein receptors and their iron-specific ligands, modulators and iron sensors. Through as yet undefined pathways, hepcidin is also homeostatically regulated by the iron requirements of erythroid precursors for hemoglobin synthesis. In accordance with the role of hepcidin-mediated iron redistribution in host defense, hepcidin production is regulated by inflammation as well. Increased hepcidin concentrations in plasma are pathogenic in iron-restrictive anemias including anemias associated with inflammation, chronic kidney disease and some cancers. Hepcidin deficiency causes iron overload in hereditary hemochromatosis and ineffective erythropoiesis. Hepcidin, ferroportin and their regulators represent potential targets for the diagnosis and treatment of iron disorders and anemias. This article is part of a Special Issue entitled: Cell Biology of Metals.

Identification of genes expressed in juvenile Haliotis rufescens in response to different copper concentrations in the north of Chile under controlled conditions

This study reports molecular markers potentially associated with resistance or sensitivity to the impact of copper in juvenile red abalone, Haliotis rufescens, in the north of Chile under experimental conditions. Genomic analysis was made applying subtractive hybridization libraries (SSH) to identify genes up-and down regulated during cooper exposure in abalone over periods of 12 and 168 h exposed to 2.5 and 10 μg/L of Cu(+2). Results obtained from the SSH library revealed 368 different sequences regulated by copper, that correspond to eight major physiological functions. The validation of these sequences obtained by SSH as well as their expression kinetics were made by PCR in real time on 14 potential genes regulated by metal stress. This study provides information for the characterization of potential genomic markers that may be used in future environmental monitoring and to investigate new mechanisms of stress to copper in this commercially important marine species.

Mass spectrometric characteristics and kinetics of iron release in visceral mass of Saccostrea cucullata

Ferritins with electrophoretic homogeneity were prepared from the visceral mass of Saccostrea cucullata in batch. The native PAGE approach showed similar electrophoretic mobility among pig pancreatic ferritin, liver ferritin of Dasyatis akajei, and visceral mass ferritin of Saccostrea cucullata. SDS-PAGE indicated that the Saccostrea cucullata visceral ferritin (SCVF) consisted of a single subunit type and had a molecular weight (MW) of approximately 20 kDa, suggesting that the protein shell in SCVF was composed of a single subunit. In addition, peptide mass fingerprinting and transmission electron microscopy were used to identify SCVF further, and to observe its molecular structure. We found that the molecular structure in SCVF was similar to that of most mammalian ferritins, which are composed of a protein shell and an iron core. The results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry under the assistance of an acidic matrix, sinapic acid, also showed that SCVF was composed of a single subunit type and its subunit MW was calculated to be 19871.042 Da in the absence of heme. Kinetics analysis revealed that the complete process of iron release fitted the law of a first-order reaction, which is similar to that of most ferritins in mammals. Similar to bacterial ferritin, studies indicated that the shell consisted of a single subunit type and showed similar kinetics of iron release, suggesting that this subunit plays two important roles in iron release and storage, and that it shows different stability and intensity of interaction in carrying out its physiological functions in SCVF.

Molecular characterization and tissue distribution of ferritin M in kelp grouper, Epinephelus bruneus

This study, reports the identification and analysis of ferritin M chain, from kelp grouper, Epinephelus bruneus (EbFerM); it comprises 1004 base pair (bp), including 528bp open reading frame (ORF) which encodes 176 amino acid (aa) residues; the calculated molecular weight is 20kDa. The 5'-untranslated region (UTR) possesses 476bp proceeded by a putative Iron Regulatory Element (IRE). Pair wise alignments showed that EbFerM shared 94% identity with that of Larimichthys crocea and Sciaenops. It is expressed in abundance in liver, spleen, and kidney when challenged with Vibrio anguillarum, lipopolysaccharide (LPS), or poly I:C.

Molecular characterization of the iron binding protein ferritin in Eisenia andrei earthworms

Ferritin is a storage protein that plays a key role in iron metabolism. In this study, we report on the sequence characterization of a ferritin-coding cDNA in Eisenia andrei earthworms isolated by RT-PCR using degenerated primers, and we suggest the presence of a putative IRE in the 5'-UTR of ferritin mRNA. The obtained ferritin sequence was compared with those of other animals showing sequence and structure homology in consensus sites, including the iron-responsive element (IRE) and ferroxidase centers. Despite the sequence homology in the E. andrei mRNA of ferritin with the sequences of other animals in consensus IRE sites, the presented cytosine in the IRE of E. andrei ferritin in the expected position does not form a conventional bulge. The presence of ferritin in the coelomic fluid of E. andrei was proven by iron staining assay. Moreover, aconitase activity in the coelomic fluid was assessed by aconitase assay, suggesting the presence of an iron regulatory protein. Quantitative analysis revealed changes in the gene expression levels of ferritin in coelomocytes in response to bacterial challenge, reaching the maximum level 8h after the stimulation with both Gram-positive and Gram-negative bacteria.

Physiological responses of the scleractinian coral Pocillopora damicornis to bacterial stress from Vibrio coralliilyticus

As the effects of climate change have become increasingly visible over the past three decades, coral reefs have suffered from a number of natural and anthropogenic disturbances that have caused a critical decline in coral populations. Among these disturbances are coral diseases, which have appeared with increasing frequency and severity, often in correlation with increases in water temperature. Although the crucial role played by Vibrio species in coral disease has been widely documented, the scientific community does not yet fully understand the infection process of Vibrio or its impact on coral physiology and immunology. Here, we investigated the physiological and transcriptomic responses of a major reef-building coral, Pocillopora damicornis, when exposed to a specific pathogen (Vibrio coralliilyticus) under virulent (increasing water temperature) and non-virulent (constant low temperature) conditions. The infection process was examined by electron microscopy and quantitative reverse-transcription PCR, and coral health was monitored by visual observations and measurements of zooxanthellar density. The results obtained suggest that coral tissue invasion occurs upon increasing water temperature only. Transcriptomic variations were investigated using a suppression–subtractive–hybridization approach, and the expression levels of six candidate immune-related genes were examined during bacterial exposure. These genes correspond to three lectin-like molecules putatively involved in the recognition of pathogens, two metal-binding proteins putatively involved in antibacterial response and one cystein protease inhibitor. The transcription patterns of these selected genes provide new insights into the responses of coral colonies to virulent versus non-virulent bacteria.