Lamprey Tissues Research Articles

Lamprey--an excellent model for iron metabolism.

After 500 million years of evolution, lamprey is in a natural environment characterized by low temperature and high iron content, and its unique adaptive evolution mode has developed its organizational structure and life mechanism in the process of metamorphosis, which provides a new direction for people to further study the origin and evolution of life. Iron is one of the essential nutrients for the human body and plays an important role in metabolic processes, but when exceeded, it can lead to iron toxicity. For example, the serum iron concentration of pre-metamorphosis larvae is 149 times that of normal males, and the iron content in the liver of juveniles is about 2-3 times that of normal humans. Lamprey has a complete biochemical system to tolerate high concentrations of free iron in the body, and high expression of important genes for iron homeostasis, such as transferrin, ferritin heavy chain, superoxide dismutase, etc., improves iron transport, iron storage and antioxidant capacity. Lamprey has an IRE/IRP regulatory system, which is an important protection mechanism for lamprey to adapt to the high iron content environment in the organization. In addition, lampreys gradually form oral glands during metamorphosis and development, which become the unique iron metabolism organs of lampreys. In this review, we mainly summarize the distribution of iron in various tissues of lamprey and the potential mechanism of adapting to the content of iron in the body, so as to provide a theoretical basis for the subsequent search for the molecular mechanism of iron metabolism.

Extensive DNA methylome rearrangement during early lamprey embryogenesis

DNA methylation (5mC) is a repressive gene regulatory mark widespread in vertebrate genomes, yet the developmental dynamics in which 5mC patterns are established vary across species. While mammals undergo two rounds of global 5mC erasure, teleosts, for example, exhibit localized maternal-to-paternal 5mC remodeling. Here, we studied 5mC dynamics during the embryonic development of sea lamprey, a jawless vertebrate which occupies a critical phylogenetic position as the sister group of the jawed vertebrates. We employed 5mC quantification in lamprey embryos and tissues, and discovered large-scale maternal-to-paternal epigenome remodeling that affects ~30% of the embryonic genome and is predominantly associated with partially methylated domains. We further demonstrate that sequences eliminated during programmed genome rearrangement (PGR), are hypermethylated in sperm prior to the onset of PGR. Our study thus unveils important insights into the evolutionary origins of vertebrate 5mC reprogramming, and how this process might participate in diverse developmental strategies.

Spatial Metabolomics Reveals the Multifaceted Nature of Lamprey Buccal Gland and Its Diverse Mechanisms for Blood-Feeding

Lampreys are blood-sucking vampires in marine environments. From a survival perspective, it is expected that the lamprey buccal gland exhibits a repository of pharmacologically active components to modulate the host’s homeostasis, inflammatory and immune responses. By analyzing the metabolic profiles of 14 different lamprey tissues, we show that two groups of metabolites in the buccal gland of lampreys, prostaglandins and the kynurenine pathway metabolites, can be injected into the host fish to assist lamprey blood feeding. Prostaglandins are well-known blood-sucking-associated metabolites that act as vasodilators and anticoagulants to maintain vascular homeostasis and are involved in inflammatory responses. The vasomotor reactivity test on catfish aortic ring showed that kynurenine can also relax the blood vessels of the host fish, thus improving the blood flow of the host fish at the bite site. Finally, a lamprey spatial metabolomics database (https://www.lampreydb.com) was constructed to assist studies using lampreys as animal model.

Ecotoxicology of mercury concentrations in arctic lamprey (Lethenteron camtschaticum)

Arctic lamprey (Lethenteron camtschaticum) is an important dietary resource for rural and indigenous communities in parts of Alaska, with some commercial use. As with many fish species harvested for human consumption, there are concerns regarding mercury concentrations ([Hg]) in Arctic lamprey that may impact human health. To date, information regarding the life cycle and diet of Arctic lamprey is scarce, with no published studies examining [Hg] in Arctic lamprey tissues. Our goals were to investigate the feeding ecology of Arctic lamprey from the Bering Sea, determine how diet and potential dietary shifts might influence [Hg] in muscle, and determine if current [Hg] may pose a human health risk. The mean total [Hg] in Arctic lamprey muscle (n = 98) was 19 ng/g wet-weight. Log transformed total [Hg] were not associated with any measured biological variables including length, mass, δ13C values, or δ15N values. A stable isotope mixing model estimated that capelin (Mallotus villosus) accounted for 40.0 ± 4.0% of the Arctic lamprey diet, while Pacific sand lance (Ammodytes hexapterus) and Pacific herring (Clupea pallasii) accounted for 37.8 ± 3.1% and 22.2 ± 3.5% respectively. Finally, diet percentage compositions shifted based on size class (i.e., medium versus large). These results indicated that feeding location, bioaccumulation, and biomagnification are not important drivers of [Hg] in Arctic lamprey and current [Hg] do not pose a human health risk. Taken together, this research further expands our knowledge of Arctic lamprey trophic ecology in the eastern Bering Sea.

A complete prostaglandin pathway from synthesis to inactivation in the oral gland of the jawless vertebrate lamprey, Lethenteron camtschaticum

Information on the prostaglandin pathway in lampreys is limited. Here, five genes related to the prostaglandin pathway from synthesis to inactivation, namely, phospholipase A2, cyclooxygenase-2, prostaglandin E synthase 3, prostaglandin D synthase, and 15-hydroxyprostaglandin dehydrogenase [NAD(+)], were screened and cloned from the lamprey, Lethenteron camtschaticum. Bioinformatic analysis showed that these lamprey genes are relatively conserved with teleost genes in domains, motifs, gene structure and 3D structure. Analysis of expression distribution of the genes in lamprey tissues revealed that a complete prostaglandin pathway from synthesis to inactivation exists in the oral gland of lamprey, especially the key gene of prostaglandin synthesis cyclooxygenase-2, which was highly expressed in the oral gland. Furthermore, cyclooxygenase-2 expression increased after LPS and Poly I:C stimulations. Using our established spatial metabolite database LampreyDB, six prostaglandin-related metabolites were screened from the oral gland of lamprey, four of which were highly expressed in the oral gland. This study provides new insights into prostaglandin synthesis and inactivation pathways in lamprey, thereby improving our understanding of the origin and evolution of the prostaglandin pathway and contributing to the recognition of lamprey regulatory mechanisms in development and immunity.

Морфофункциональные особенности органов волжской миноги

With habitats shrinking (e.g. due to construction projects that prevent access to areas upper the Volgograd Reservoir), changes in the environment, or illegal fishing in some areas, there is registered a sharp decrease of the population of Volga lamprey. Studying the histomorphological structure of this species has a significant impact on the prediction of changes in the population and on the assessment of the state of their internal organization. Problems in such sections as comparative embryology and histology of Volga lamprey have been poorly studied, which complicates the research. The aim of the research is to study the morphofunctional features of the organs of Caspian lamprey. The object of the study is Caspian (Volga) lamprey (Caspiomyzon wagneri), which is endemic to the Caspian Sea basin. The organs and tissues of lamprey were treated for the study in accordance with the methods generally accepted in histology. Microscopy of fixed, stained preparations was performed using a light microscope with immersion. Lampreys differ from other fish. The structure of the gill apparatus, the skin structural features, the structure of the digestive system organs, the structural features of the organs of the excretory and reproductive systems have been considered. The most intense pathological processes were characteristic of the gills, as the organ actively contacts with the environment. The studied species showed signs of epithelial hyperplasia, vascular disorders, and a change in the shape of lamellae.

Cartilage diversification and modularity drove the evolution of the ancestral vertebrate head skeleton

The vertebrate head skeleton has evolved a myriad of forms since their divergence from invertebrate chordates. The connection between novel gene expression and cell types is therefore of importance in this process. The transformation of the jawed vertebrate (gnathostome) head skeleton from oral cirri to jointed jaw elements required a diversity of cartilages as well as changes in the patterning of these tissues. Although lampreys are a sister clade to gnathostomes, they display skeletal diversity with distinct gene expression and histologies, a useful model for addressing joint evolution. Specifically, the lamprey tissue known as mucocartilage has noted similarities with the jointed elements of the mandibular arch in jawed vertebrates. We thus asked whether the cells in lamprey mucocartilage and gnathostome joint tissue could be considered homologous. To do this, we characterized new genes that are involved in gnathostome joint formation and characterized the histochemical properties of lamprey skeletal types. We find that most of these genes are minimally found in mucocartilage and are likely later innovations, but we do identify new activity for gdf5/6/7b in both hyaline and mucocartilage, supporting its role as a chondrogenic regulator. Contrary to previous works, our histological assays do not find any perichondrial fibroblasts surrounding mucocartilage, suggesting that mucocartilage is non-skeletogenic tissue that is partially chondrified. Interestingly, we also identify new histochemical features of the lamprey otic capsule that diverge from normal hyaline. Paired with our new insights into lamprey mucocartilage, we propose a broader framework for skeletal evolution in which an ancestral soxD/E and gdf5/6/7 network directs mesenchyme along a spectrum of cartilage-like features.

Identification and characterization of the lamprey cathepsin genes.

Cathepsins are key mammalian proteases that play an important role in the immune response. Several studies have revealed the versatile and critical functions of cathepsins. Here, we obtained ten kinds of cathepsin homologs and identified seven homologs with complete coding sequences. Phylogenetic analysis verified their identities and supported the classification of cathepsins into seven families, which is similar to other vertebrates. Tissue-specific expression analysis showed that all lamprey cathepsins (L-cathepsins) are present in the supraneural body (SB), kidney, gill, intestine, brain, heart, and liver, but their relative abundance varied among tissues. Additionally, we focused on the lamprey cathepsin L (L-cathepsin L) and used recombinant L-cathepsin L protein (rL-cathepsin L) to prepare anti rL-cathepsin L polyclonal antibodies, which were used to detect its distribution in lamprey tissues. The L-cathepsin L protein was primarily detected in the SB, kidney, gill, intestine, brain, and liver via western blot and immunohistochemistry assays. Importantly, quantitative real-time PCR (RT-PCR) revealed that the expression level of L-cathepsins mRNA significantly increased after exposure to three different stimuli (poly I:C, Staphylococcus aureus (S.a) and Vibro anguilarum (V.an)). This suggested that L-cathepsins may participate in defense processes. These results revealed that L-cathepsins may play key roles in the immune response to exogenous stimuli. The findings provide important information for future studies aiming to understand the molecular mechanisms underlying the immune response to pathogen invasion in lamprey.

Comparison of stable isotope ratios in larval Pacific lamprey tissues and their nutritional sources when reared on a mixed diet

Aquaculture of larval lampreys (ammocoetes), to help recover and maintain threatened populations, is increasingly viewed as an important management tool. Ammocoetes are filter-feeders that remain burrowed in fine grain substrates for the majority of their lives, making it difficult to determine how well diets are being supplied and in what proportions various foods are utilized. Stable isotope analysis offers the ability to distinguish which foods are being incorporated into animal biomass. While muscle tissue is most commonly used for stable isotope analysis, other tissues could also be collected to avoid lethal sampling (e.g., blood) or to provide insight into condition (e.g., liver). Muscle, red blood cells (RBC), plasma, liver, and notochord were collected from Pacific lamprey (Entosphenus tridentatus) larvae raised in the laboratory on a varied diet; δ2H, δ13C, δ15N, δ18O and δ34S were measured in food sources, animal tissues, and lipid-extracted muscle. Tissues were generally isotopically similar to one another except in a few notable cases. The δ2H of notochord was more enriched than any other tissue and the δ15N and δ34S of RBC were elevated over muscle. The δ18O of all tissues was predicted from source water, allowing this isotope ratio to provide information about regional origin of lampreys. A stable isotope mixing model found that larval biomass, even when ammocoetes were supplied with various diet items, was still primarily dependent on aquatic sediments. Therefore, the burrowing medium supplied to ammocoetes in aquaculture facilities is likely to have a strong impact on growth rate and may benefit from the inclusion of more labile organic material or feed that specifically enriches the aquatic sediment.

Histology and 3D Modeling of the Connective Tissue Skeleton in the Trunk of a Lamprey (Petromyzon marinus)

Agnathan lampreys play a key role in the reconstruction of the evolutionary history of vertebrates and, more specifically, in the analysis of the biomechanics underlying piscine undulatory locomotion. However, the morphology of the fibrous skeletal framework for their trunk musculature is still incompletely understood, mainly because of the complex spatial configuration of the segmentally arranged myosepta and muscle fibers within the myomeres. To contribute to a better understanding of how contractile muscular forces are transmitted via the fibrous skeletal framework of the trunk, the architecture and composition of the connective tissue structures (dermis, dorsal longitudinal ligament, hypodermis, myosepta, perimysial lamellae, notochord, fasciae) and their relationship to the muscle fibers of the myomeres were analyzed through histological techniques (in addition to MRI and microdissection described elsewhere) and 3D modeling based on a 3D reconstruction of serial histological sections treated with special stains (e.g., Movat Pentachrome, Ladewig Trichrome). These stains, however, did not differentiate tissue types as expected, probably because lamprey tissue fiber types differ biochemically from mammalian ones, but they discriminate a wide range of fiber types. As to the distribution of connective tissue fibers, the dermis comprises about 25 layers of helically arranged collagen fibers with the most superficial layers anchoring to the basement membrane of the epidermis and the deepest layers connecting to fibers of the hypodermis, which is separated by the pigment layer from the dermis. Radially arranged collagen fibers interconnect the basement membrane and hypodermis. Also within the hypodermis, the dorsal longitudinal ligament collects and interbraids collagen fibers from the dermis, hypodermis, and dorsal vertical septum, and, ultimately, the myosepta. The latter comprise tendon fibers connecting the roughly longitudinally oriented muscle fibers of adjacent myomeres and are traversed by thick collagen fiber bundles that run from the dermis to the central periaxial and perivisceral fasciae, as well as by thin reticulated fibers that support intramyoseptal nerves and blood vessels. The muscle blocks of the myomeres are separated by radially arranged perimysial lamellae running from the hypodermis to the periaxial and perivisceral fasciae. During undulations, contracting muscle fibers between the myosepta shorten and expand radially. This expansion is resisted by the radially arranged collagen fibers within the myosepta and perimysial lamellae. As a result, the internal pressure and, hence, the turgidity of the trunk is raised. A detailed understanding of the connective tissue fiber configuration in lampreys provides the necessary basis for building dynamic 3D models of the biomechanics involved in locomotion and other behaviors.Support or Funding InformationGrant‐In‐Aid of Research from Sigma Xi, the Scientific Research Society, to Bradley M. Wood; LSU Foundation support to Dominique G. HombergerThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Characterization of the LECT2 gene and its protective effects against microbial infection via large lymphocytes in Lampetra japonica

Leukocyte cell-derived chemotaxin 2 (LECT2) is a multifunctional protein of the innate immune system that defends against bacterial infections and chemotactic activity. However, its precise function in lamprey remains unclear. In this study, a novel LECT2 gene was first cloned from Lampetra japonica. The full-length cDNA sequence of L-LECT2 consists of a 606-bp ORF encoding a protein of 201 amino acid residues. L-LECT2 has greater than 50% sequence identity with its homologs in jawed vertebrates. FACS and immunohistochemistry assays were used to determine that the L-LECT2 protein was primarily distributed in the intestines and supraneural body tissues of lamprey, also marginally detectable in leukocytes. However, the expression of L-LECT2 was differentially upregulated in the intestines and heart after treatment with LPS. The recombinant L-LECT2 resulted in significant promoting migration of the leukocytes in vitro. Our data demonstrate that L-LECT2 treatment could enhance phagocytosis in lamprey large lymphocytes. Thus, our results suggest that LECT2 can modulate the host defense in lamprey and mediate antibacterial protection against E.coli through large lymphocytes.

A validated LC-MS/MS method for thyroid hormone determination in sea lamprey (Petromyzon marinus) plasma, gill, kidney and liver.

A UPLC-MS/MS method was developed to provide a reproducible, sensitive and quantitative assay to determine thyroid hormones in sea lamprey tissues and plasma. l-Thyroxine (T4) and its two triiodo-thyronine isomers have been simultaneously quantified and validated for plasma, gill, liver, and kidney matrices. Multiple sample preparation techniques were investigated to achieve optimal sample matrix digestion and clean-up. Enzymatic digestion followed by protein precipitation was selected to process the samples. The developed method exhibited excellent linearity for all analytes with regression coefficients higher than 0.99 for concentrations ranged from 10 to 50,000pg/mL. The limit of detection (LOD) was under 1pg/mL while the limit of quantification (LOQ) was estimated as 10pg/mL. This method was validated according to the FDA guidance and applied to determine thyroid hormone levels in plasma, gill and kidney of sea lamprey exposed to a sex pheromone. With appropriate implementation and further validation, this method could be applied to tissues in other species including humans.

Sea lamprey avoid areas scented with conspecific tissue extract in Michigan streams

AbstractThree in‐stream experiments were conducted to determine whether sea lamprey, Petromyzon marinus L., tissue extract (alarm cue) and 2‐phenylethylamine hydrochloride (PEA HCl, a putative predator cue) influenced the distribution of migrating adult sea lamprey. Experiments evaluated sea lamprey movement when an odour was applied to (1) a tributary of a larger stream; and (2) half of a stream channel. Fewer sea lamprey entered the tributary and side of the river scented with sea lamprey tissue extract compared to the control treatment. Sea lamprey did not avoid the tributary and side of the river scented with PEA HCl. A final laboratory experiment found no difference in the avoidance response of sea lamprey to PEA HCl mixed with river water vs PEA HCl mixed with water from Lake Huron. As such, the lack of sea lamprey response to PEA HCl in the stream was unlikely to have been caused by the presence of the river water. Rather, the difference between laboratory and field results may be attributed to the complexity of the physical environment.

Quantification of Oxidized and Unsaturated Bile Alcohols in Sea Lamprey Tissues by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry.

A sensitive and reliable method was developed and validated for the determination of unsaturated bile alcohols in sea lamprey tissues using liquid-liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The liver, kidney, and intestine samples were extracted with acetonitrile and defatted by n-hexane. Gradient UHPLC separation was performed using an Acquity BEH C18 column with a mobile phase of water and methanol containing 20 mM triethylamine. Multiple reaction monitoring modes of precursor-product ion transitions for each analyte was used. This method displayed good linearity, with correlation coefficients greater than 0.99, and was validated. Precision and accuracy (RSD %) were in the range of 0.31%–5.28%, while mean recoveries were between 84.3%–96.3%. With this technique, sea lamprey tissue samples were analyzed for unsaturated bile alcohol analytes. This method is practical and particularly suitable for widespread putative pheromone residue analysis.

Biological responses of midge (Chironomus riparius) and lamprey (Lampetra fluviatilis) larvae in ecotoxicity assessment of PCDD/F-, PCB- and Hg-contaminated river sediments.

We evaluated the utility of chironomid and lamprey larval responses in ecotoxicity assessment of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F)-, polychlorinated biphenyls (PCB)- and mercury (Hg)-contaminated river sediments. Sediment samples were collected from the River Kymijoki with a known industrial pollution gradient. Sediment for the controls and lamprey larvae were obtained from an uncontaminated river nearby. Contamination levels were verified with sediment and tissue PCDD/F, PCB and Hg analyses. Behaviour of sediment-exposed chironomid and lamprey larvae were measured with Multispecies Freshwater Biomonitor© utilizing quadrupole impedance conversion technique. In addition, mortality, growth and head capsule deformity incidence of chironomids were used as ecotoxicity indicators. WHOPCDD/F+PCB-TEQ in the R. Kymijoki sediments ranged from the highest upstream 22.36ngg(-1) dw to the lowest 1.50ngg(-1) near the river mouth. The sum of PCDD/Fs and PCBs correlated strongly with Hg sediment concentrations, which ranged from <0.01 to 1.15μgg(-1). Lamprey tissue concentrations of PCDD/Fs were two orders and PCBs one order of magnitude higher in the R. Kymijoki compared to the reference. Chironomid growth decreased in contaminated sediments and was negatively related to sediment ∑PCDD/Fs, WHOPCDD/F+PCB-TEQ and Hg. There were no significant differences in larval mortality or chironomid mentum deformity incidence between the sediment exposures. The distinct behavioural patterns of both species indicate overall applicability of behavioural MFB measurements of these species in sediment toxicity bioassays. Chironomids spent less and lampreys more time in locomotion in the most contaminated sediment compared to the reference, albeit statistically significant differences were not detected. Lamprey larvae had also a greater activity range in some of the contaminated sediments than in the reference. High pollutant levels in lamprey indicate risks for biomagnification in the food webs, with potential health risks to humans consuming fish.

Molecular cloning, expression pattern, and phylogenetic analysis of a tetraspanin CD82-like molecule in lamprey Lampetra japonica.

CD82, a member of the tetraspanins, is originally identified as an accessory molecule in T cell activation, and it participates in the formation of immune synapse both in T cells and antigen-presenting cells of jawed vertebrates. In the present study, a CD82 homologous complementary DNA (cDNA) sequence is identified in the lamprey Lampetra japonica. The open reading frame of this sequence is 801bp long and encodes a 266-amino acid protein. The multialignment of this sequence with several typical CD82s and CD37s of jawed vertebrates shows that it also possesses their conserved four transmembrane domains and a six-cysteine motif Cys-Cys-Gly…Cys-Ser-Cys…Cys…Cys, which is a characteristic motif of CD82 and CD37 vertebrate tetraspanin sequences. Since it is close to CD82s in sequence similarity, we name it as Lja-CD82-like. From the distribution profile of the conserved motifs of CD82-like, CD82, and CD37 molecules from molluscas to mammals, it seems that the CD82s and CD37s evolved from a common ancestral gene through a gene duplication event to their modern forms by a short insertion or substitution approaches. The phylogenetic analysis indicated that CD82 and CD37 molecules of jawed vertebrates originated from a common ancestral gene which is close to agnathan CD82-like and evolved into two distinct paralogous groups maybe after the divergence of jawed and jawless vertebrates. An expression vector with trigger factor (TF) was constructed to ensure that Lja-CD82-like express in prokaryotic expression host. The expressions of Lja-CD82-like messenger RNA (mRNA) and protein in immune-related tissues of lamprey were detected by real-time quantitative polymerase chain reaction and western blotting. Results showed that the mRNA and the protein levels of Lja-CD82-like were significantly upregulated in lymphocyte-like cells, gills, and supraneural myeloid bodies after stimulation with mixed antigens, respectively. Our data provided a foundation for the further study of Lja-CD82-like and its role in immune response process of jawless vertebrates.

Ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of natural steroid hormones in sea lamprey (Petromyzon marinus) plasma and tissues.

This study aims to provide a rapid, sensitive and precise UPLC-MS/MS method for target steroid quantitation in biological matrices. We developed and validated an UPLC-MS/MS method to simultaneously determine 16 steroids in plasma and tissue samples. Ionization sources of Electrospray Ionization (ESI) and Atmospheric Pressure Chemical Ionization (APCI) were compared in this study by testing their spectrometry performances at the same chromatographic conditions, and the ESI source was found up to five times more sensitive than the APCI. Different sample preparation techniques were investigated for an optimal extraction of steroids from the biological matrices. The developed method exhibited excellent linearity for all analytes with regression coefficients higher than 0.99 in broad concentration ranges. The limit of detection (LOD) was from 0.003 to 0.1ng/mL. The method was validated according to FDA guidance and applied to determine steroids in sea lamprey plasma and tissues (fat and testes) by the developed method.

Cell secretion from the adult lamprey supraneural body tissues possesses cytocidal activity against tumor cells.

The supraneural body was identified in the adult lamprey, and its secretions induced the death of a variety of tumor cells but had no effect on normal cells. The cell secretions from different lamprey tissues were separated, and these secretions killed human tumor cells to varying degrees. The cell secretions induced remarkable cell morphological alterations such as cell blebbing, and the plasma membrane was destroyed by the secretions. In addition, the secretions induced morphological alterations of the mitochondria, cytoskeletal structure, and endoplasmic reticulum, eventually leading to cell death. These observations suggest the presence of a novel protein in the lamprey and the possibility of new applications for the protein in the medical field.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-015-1270-6) contains supplementary material, which is available to authorized users.

Reconnaissance of contaminants in larval Pacific lamprey (Entosphenus tridentatus) tissues and habitats in the Columbia River Basin, Oregon and Washington, USA

Pacific lampreys (Entosphenus tridentatus) have resided in the Columbia River Basin for millennia and have great ecological and cultural importance. The role of habitat contamination in the recent decline of the species has rarely been studied and was the main objective of this effort. A wide range of contaminants (115 analytes) was measured in sediments and tissues at 27 sites across a large geographic area of diverse land use. This is the largest dataset of contaminants in habitats and tissues of Pacific lamprey in North America and the first study to compare contaminant bioburden during the larval life stage and the anadromous, adult portion of the life cycle. Bioaccumulation of pesticides, flame retardants, and mercury was observed at many sites. Based on available data, contaminants are accumulating in larval Pacific lamprey at levels that are likely detrimental to organism health and may be contributing to the decline of the species.

An UPLC-MS/MS method for quantitative profiling of bile acids in sea lamprey plasma and tissues.

Bile acids (BAs) have recently gained more attention because of their diverse roles from digestion to signaling. Simultaneous analyses of various BAs in biological samples are challenging due to their structural similarity, relatively low concentrations, and the presence of isomeric forms. In this study, we report a simple and sensitive UPLC-MS/MS method for simultaneous quantifications of 13 BAs including four unique sea lamprey BAs in sea lamprey plasma, liver, intestine, and gills. A straightforward protein precipitation (PPT) method was used to extract BAs from the biological samples. Separation of all target analytes was achieved on a reverse-phase UPLC column in 15min, and detection was carried out on MS/MS with ESI in the negative ionization mode. This method was validated regarding its linearity, limits of detection (LOD), recovery, matrix effect, reproducibility, accuracy and precision. Significant improvements compared to previous LC-MS/MS methods were observed as a result of the application of UPLC and extensive optimization of experimental conditions. The method showed excellent linearity with high regression coefficients (>0.99) over a range of 0.5-1000ng/mL and LODs ranged from 0.009 to 0.11ng/mL. The applications of the developed method demonstrated that it simultaneously determined all target BAs in different biological sample matrices with excellent sensitivity, selectivity and reproducibility.