Immunohistochemical localization of endothelin-1 in the nervous system of the earthworm Eisenia foetida

Investigating the deep supercooling ability of an Alaskan beetle, Cucujus clavipes puniceus, via high throughput proteomics

Cucujus clavipes puniceus is a freeze avoiding beetle capable of surviving the long, extremely cold winters of the Interior of Alaska. Previous studies showed that some individuals typically supercool to mean values of approximately -40 °C, with some individuals supercooling to as low as -58 °C, but these non-deep supercooling (NDSC) individuals eventually freeze if temperatures drop below this. However, other larvae, especially if exposed to very cold temperatures, supercool even further. These deep supercooling (DSC) individuals do not freeze even if cooled to -100 °C. In addition, the body water of the DSC larvae vitrifies (turns to a glass) at glass transition temperatures of -58 to -70 °C. This study examines the proteomes of DSC and NDSC larvae to assess proteins that may contribute to or inhibit the DSC trait. Using high throughput proteomics, we identified 138 proteins and 513 Gene Ontology categories in the DSC group and 104 proteins and 573 GO categories in the NDSC group. GO categories enriched in DSC include alcohol metabolic process, cellular component morphogenesis, monosaccharide metabolic process, regulation of biological quality, extracellular region, structural molecule activity, and antioxidant activity. Proteins unique to DSC include alpha casein precursor, alpha-actinin, vimentin, tropomyosin, beta-lactoglobulin, immunoglobulins, tubulin, cuticle proteins and endothelins.

Lumbricus extract promotes the regeneration of injured peripheral nerve in rats

BACKGROUND

Earthworms regenerate amputated parts of their body if the nervous system is intact. Lumbricus is one traditional Chinese medicine (TCM), which has been used in China to promote nerve function for hundreds of years.

AIM OF THE STUDY

To investigate the beneficial effect of lumbricus extract on peripheral nerve regeneration in rats.

MATERIALS AND METHODS

Nerve function was surgically impaired in Sprague-Dawley (SD) rats by clamping of the left sciatic nerve. The sham-operated group (surgery but no sciatic nerve clamping), control group, and treatment group were treated with 2 ml 0.9% NaCl, 0.9% NaCl, and lumbricus extract (1g/ml), respectively. Treatments were administered once daily after the operation for 6 weeks. During this period, motor function was monitored by walking track analysis, conduction function of injured sciatic nerve was monitored by electrophysiology, and regeneration of myelinated nerve was assessed by immunohistochemistry.

RESULTS

(1) For nerve function index value, treatment group is higher than control group. (2) For conduction velocity of injured sciatic nerve, treatment group is higher than control group at week 3 and 6. (3) For the number of regenerated myelinated nerve fibers, treatment group is higher than control group at week 2 and 6.

CONCLUSIONS

Lumbricus extract appears to enhance sciatic nerve regeneration and function recovery following injury, suggesting the clinical potential of lumbricus extract on the treatment of peripheral nerve injury in humans.

Biology of Lysenin, a Protein in the Coelomic Fluid of the Earthworm Eisenia foetida

Lysenin is a protein of 33?kDa in the coelomic fluid (CF) of the earthworm Eisenia foetida. It differs from other biologically active proteins, such as fetidins, eiseniapore, and coelomic cytolytic factor (CCF-1), that have been found in Eisenia foetida, in terms of both its biochemical and its biological characteristics. The large coelomocytes and free chloragocytes in the typhlosole of Eisenia foetida appear to be the cells that produce lysenin since the mRNA for lysenin and immunoreactive lysenin have been found in these cells. Lysenin binds specifically to sphingomyelin (SM) but not to other phospholipids in cell membranes. After binding to the cell membranes of target cells, lysenin forms oligomers in an SM-dependent manner, with subsequent formation of pores with a hydrodynamic diameter of approximately 3?nm. The biochemical interactions between lysenin and SM in cell membranes are responsible for the pharmacological activities of lysenin and of CF that contains lysenin in vertebrates, such as hemolysis, cytotoxicity, and contraction of smooth muscle in vitro and vasodepressor activity and lethality in vivo. When incubated with SM-liposomes, CF and lysenin lost some or all of their activity, an observation that suggests that SM might be involved in the induction of the various activities of lysenin and CF. However, in general, lysenin is neither cytotoxic nor lethal to invertebrates. An attempt has been made to explain the differences in the responses to lysenin and CF between vertebrates and invertebrates in terms of the presence or absence of SM in the various animals. Among Protostomia, SM is absent in Lophotrochozoa, with the exception of some molluscan species, but it is present in Ecdysozoa, with the exception of Nematomorpha and flies. Among Deuterostomia, Echinodermata and Hemichordata lack SM but SM is found in Chordata. Thus, the difference in terms of the response to lysenin between invertebrates and vertebrates cannot be fully explained by reference to the presence or absence of SM in the organism. Lysenin and its antiserum have made it possible to localize SM in the cell membranes. They should be a useful tool for studies of membrane physiology and the role of SM.

Structure, evolutionary conservation, and functions of angiotensin- and endothelin-converting enzymes

Angiotensin-converting enzyme, a member of the M2 metalloprotease family, and endothelin-converting enzyme, a member of the M13 family, are key components in the regulation of blood pressure and electrolyte balance in mammals. From this point of view, they serve as important drug targets. Recently, the involvement of these enzymes in the development of Alzheimer's disease was discovered. The existence of homologs of these enzymes in invertebrates indicates that these enzyme systems are highly conserved during evolution. Most invertebrates lack a closed circulatory system, which excludes the need for blood pressure regulators. Therefore, these organisms represent excellent targets for gaining new insights and revealing additional physiological roles of these important enzymes. This chapter reviews the structural and functional aspects of ACE and ECE and will particularly focus on these enzyme homologues in invertebrates.

An endothelin-converting enzyme homologue in the locust, Locusta migratoria: functional activity, molecular cloning and tissue distribution

Endothelin-converting enzyme is the key enzyme in the process of endothelin production. Endothelin is a peptide that plays an important role in vasoconstriction and the development of neural crest-derived cells in vertebrates. Activity assays performed on membrane extracts from Locusta migratoria brain revealed the existence of a protease activity responsible for the formation of mature endothelin-1 from its precursor, big endothelin. Cloning experiments led to a cDNA sequence (Lom ECE) with an open reading frame of 727 amino acid residues displaying all the characteristic ECE features. A comparison of ECE activity levels among different tissues of the locust showed a high enzyme activity in the gonads and midgut. RT-PCR experiments showed a wide tissue distribution of Lom ECE mRNA, with transcription being most abundant in brain tissue.

Structure, expression, and developmental function of early divergent forms of metalloproteinases in hydra

Metalloproteinases have a critical role in a broad spectrum of cellular processes ranging from the breakdown of extracellular matrix to the processing of signal transduction-related proteins. These hydrolytic functions underlie a variety of mechanisms related to developmental processes as well as disease states. Structural analysis of metalloproteinases from both invertebrate and vertebrate species indicates that these enzymes are highly conserved and arose early during metazoan evolution. In this regard, studies from various laboratories have reported that a number of classes of metalloproteinases are found in hydra, a member of Cnidaria, the second oldest of existing animal phyla. These studies demonstrate that the hydra genome contains at least three classes of metalloproteinases to include members of the 1) astacin class, 2) matrix metalloproteinase class, and 3) neprilysin class. Functional studies indicate that these metalloproteinases play diverse and important roles in hydra morphogenesis and cell differentiation as well as specialized functions in adult polyps. This article will review the structure, expression, and function of these metalloproteinases in hydra.

Molecular and functional evidence for early divergence of an endothelin-like system during metazoan evolution: analysis of the Cnidarian, hydra

A novel putative endothelin-converting enzyme (ECE) has been cloned from hydra, a freshwater invertebrate that belongs to the second oldest phylum of the animal kingdom. As an integral component of the endothelin system, vertebrate ECE functions in the activation of endothelin (ET) peptides. Vertebrate ETs are (1) the most potent vasoconstrictors known in mammals; and (2) function as essential signaling ligands during development of tissues derived from neural crest cells. To date, only a limited number of immunocytochemical studies have suggested the presence of endothelin-like peptides in invertebrates. Based on structural and functional analyses, we present evidence for a functional endothelin-like system in hydra that is involved in both muscle contraction and developmental processes. These findings indicate the broad use of endothelin systems in metazoans and also indicate that this type of signaling system arose early in evolution even before divergence of protostomes and deuterostomes.

Molecular cloning of cDNA for lysenin, a novel protein in the earthworm Eisenia foetida that causes contraction of rat vascular smooth muscle

Lysenin, which causes contraction of rat vascular smooth muscle, is a protein that was isolated from the earthworm Eisenia foetida. A cDNA encoding lysenin was isolated by use of a partial cDNA probe that had been generated by the PCR with a primer designed by reference to an internal peptide sequence of lysenin. This clone had an ORF encoding 297 amino acid residues. The amino acid sequence deduced from the cDNA revealed the absence of any significant homology to those of previously characterized vasoactive substances. The recombinant lysenin was produced in Escherichia coli. This protein and native lysenin isolated from the earthworm had similar contractive activities when tested on rat aorta. Northern blot analysis of the RNA from various tissues of the earthworm indicated that lysenin is produced by the coelomocytes.

Physiological role of brain endothelin in the central autonomic control: from neuron to knockout mouse

Although endothelin (ET) was discovered as a potent vascular endothelium-derived constricting peptide, its presumed physiological and pathophysiological roles are now considered much more diverse than originally though. Endothelin in the brain is thought to be deeply involved in the central autonomic control and consequent cardiorespiratory homeostasis, possibly as a neuromodulator or a hormone that functions locally in an autocrine/paracrine manner or widely through delivery by the cerebrospinal fluid (CSF). This notion is based on the following lines of evidence. (1) Mature ET, its precursors, converting enzymes, and receptors all are detected at strategic sites in the central nervous system (CNS), especially those controlling the autonomic functions. (2) The ET is present in the CSF at concentrations higher than in the plasma. (3) There is a topographical correspondence of ET and its receptors in the CNS. (4) The ET is released by primary cultures of hypothalamic neurons. (5) When ET binds to its receptors, intracellular calcium channels. (6) An intracerebroventricular or topical application of ET to CNS sites elicits a pattern of cardiorespiratory changes accompanied by responses of vasomotor and respiratory neurons. (7) Recently generated knockout mice with disrupted genes encoding ET-1 exhibited, along with malformations in a subset of the tissues of neural crest cell lineage, cardiorespiratory abnormalities including elevation of arterial pressure, sympathetic overactivity, and impairment of the respiratory reflex. Definitive evidence is expected from thorough analyses of knockout mice by applying conventional experimental methods.

Sarafotoxins and endothelins: evolution, structure and function

The venom of the burrowing asp Atractaspis engaddensis contains several 21 amino acid residue peptides known as sarafotoxins. The sarafotoxins are homologous to the mammalian endothelin family, and they have similar biological activities. This review covers recent advances in the study of the chemical and biological properties of the sarafotoxins and endothelins.

Mitogenicity of the earthworm's (Eisenia foetida) insulin-like proteins

1. Biologically active glycolipoprotein complex (G-90), isolated from whole earthworm tissue extract (Eisenia foetida), was separated into seven fractions by gel-filtration. 2. It has been shown by radioimmunoassay that each of the fractions, except the lightest one, is cross-reactive with porcine anti-insulin antibodies. Molecules that possess such activity were detected by immunoblotting. 3. All fractions, except the heaviest and the lightest one, stimulate mammalian normal and transformed cell proliferation in serum-free conditions in vitro. The intensity of stimulation depends on cell type. Stimulation is completely abolished if the medium is supplemented with fetal calf serum.

Activity of sarafotoxin/endothelin peptides in the heart and brain of lower vertebrates

The effects of sarafotoxin-b (SRTX-b) and endothelin-1 (ET-1) were tested in the fish tilapia (Ore niloticus x O. aureus hybrids) and torpedo (Torpedo ocellata), the toad (Bufo viridis), the agama lizard (Agama stellio) and water snake (Natrix tessellata). In isolated heart preparations of the fish and agama, peptide doses of 0.05-0.5 micrograms/ml induced positive inotropic effects, reduction of the contraction rate and arrhythmia, leading to cardiac arrest. In the toad, a negative inotropic effect and a reduction of the contraction rate were observed, whereas the water snake was hardly affected by either SRTX-b or ET-1. In the agama, an i.v. injection of 15 micrograms of SRTX-b caused changes in the ECG, culminating in A-V block that led to cardiac arrest, while in the toad an injection of 45 micrograms induced only transient disturbances in the ECG. Binding studies with 125I-SRTX-b revealed specific binding sites for SRTX-b and ET-1 in the heart and brain preparations of fish (tilapia and torpedo) and agama, whereas no specific binding could be demonstrated in the toad or in the snake. These results suggest that most vertebrates tested are sensitive to SRTX/ET, while the snake may possess receptors that are of a different structure.