Fire-prone Rhamnaceae with South African affinities in Cretaceous Myanmar amber

The rapid Cretaceous diversification of flowering plants remains Darwin's 'abominable mystery' despite numerous fossil flowers discovered in recent years. Wildfires were frequent in the Cretaceous and many such early flower fossils are represented by charcoalified fragments, lacking complete delicate structures and surface textures, making their similarity to living forms difficult to discern. Furthermore, scarcity of information about the ecology of early angiosperms makes it difficult to test hypotheses about the drivers of their diversification, including the role of fire in shaping flowering plant evolution. We report the discovery of two exquisitely preserved fossil flower species, one identical to the inflorescences of the extant crown-eudicot genus Phylica and the other recovered as a sister group to Phylica, both preserved as inclusions together with burned plant remains in Cretaceous amber from northern Myanmar (~99 million years ago). These specialized flower species, named Phylica piloburmensis sp. nov. and Eophylica priscastellata gen. et sp. nov., exhibit traits identical to those of modern taxa in fire-prone ecosystems such as the fynbos of South Africa, and provide evidence of fire adaptation in angiosperms.

The complete chloroplast genome sequence of Ehrharta erecta Lam. (Poaceae)

The complete chloroplast (cp) genome of Ehrharta erecta was sequenced and assembled for the first time. In this study, The total genome size is 134,511 bp in length and demonstrates a typical quadripartite structure containing a large single copy (LSC, 95,227 bp) and a small single copy (SSC, 12,306 bp), separated by a pair of inverted repeats (IRa, IRb) of 13,489 bp. The G + C content of this chloroplast genome was 38.76%. Gene annotation analysis identified 130 genes including 84 protein-coding genes, 38 transfer RNA, and 8 ribosomal RNA genes. The maximum-likelihood phylogenetic analysis result showed that E. erecta was closely related to O. sativa in the phylogenetic relationship.

The complete chloroplast genome sequence of Oryza sativa Temperate japonica

In this study, the complete chloroplast genome of O. sativa Temperate Japonica YunJing-24 was assembled using Illumina sequencing data. The complete chloroplast (cp) genome is 134,556 bp in length, including a pair of invert repeats (IRA and IRB) regions of 20,797 bp, large single-copy (LSC) region of 80,615 bp, and small single-copy (SSC) region of 12,347 bp. A total of 129 genes were predicted in the genome, including 87 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Phylogenetic analysis confirmed the phylogenetic relationship between O. sativa Temperate Japonica and other representative species.

Anatomy of the deep branch of the ulnar nerve

The aim of this study was to provide a clear description of the course, precise branching pattern and distribution of the deep branch of the ulnar nerve. A total of 36 hands from 18 preserved cadavers were dissected. The vertical distance from the pisoscaphoid line to the crossing points between the deep branch of the ulnar nerve and each metacarpal was about 4 cm. The deep branch of the ulnar nerve gave off two types of muscular branches: (1) trunks that innervate more than two intrinsic hand muscles; and (2) multiple separate branches innervating only a single muscle. The median numbers of trunks and separate branches were 5 and 6, respectively.

LEVELS OF EVIDENCE

N/A.

Properties of Dye-Sensitized Solar Cells Using Carbon Nanowall Counter Electrodes

This research investigates plasma-treated and metal-coated carbon nanowalls (CNWs) for use as counter electrodes of dye-sensitized solar cells (DSSCs). The CNWs were synthesized on a fluorine-tin-oxide (FTO) glass substrate using the microwave plasma-enhanced chemical vapor deposition (PECVD) system with methane (CH4) gas. The post-plasma treatment was performed on the CNWs with hydrogen (H2) plasma using PECVD, and the CNWs were sputter-coated with metal films using the RF magnetron sputtering system with a four-inch tungsten (W) target. Then the post-plasma-treated and metal-coated CNWs were used as counter electrodes for the fabrication of the DSSCs. Field-emission scanning electron microscopy (FE-SEM) was performed to obtain cross-sectional and planar images of the grown CNWs. The energy conversion efficiencies of the DSSCs manufactured using the post-plasma-treated and metal-layer-coated CNWs as the counter electrodes were measured.

Morphological and morphometric study of the androgenetic alopecic scalp using two- and three-dimensional analysis comparing regional differences

BACKGROUND

Androgenetic (male-type) alopecia (AGA) is caused by genetic and androgenetic effects. The progression of baldness results in smaller hair papillae, thinner hair and a shortened hair cycle. Alopecia occurs mainly in the frontal region and, to a lesser extent, in the occipital region.

OBJECTIVES

The morphological differences in the hair follicular units between the alopecic frontal scalp and the vertex and occipital regions were compared using cross-sectional histology and three-dimensional reconstruction.

METHODS

Skin specimens were obtained from the frontal, vertex and occipital regions of 24 male human cadavers with fully progressed AGA, and from the frontal region of 32 normal cadaveric scalps. These specimens were fixed, processed using routine histological methods, serially sectioned at a thickness of 10 μm and then stained with Masson's trichrome. The serial sections were reconstructed three-dimensionally using 'Reconstruct' software.

RESULTS

The ratios between the numbers of terminal and vellus hairs in the frontal and occipital regions in the AGA scalps were 0·2 : 1 and 3·5 : 1, respectively. Almost all of the hair follicles in the frontal region were vellus hair follicles. The sebaceous gland and arrector pili muscle were larger in the frontal region than in the occipital region.

CONCLUSIONS

The morphology of the AGA scalp has been characterized. The terminal-to-vellus hair ratio in the occipital (normal) region was different from that in the frontal (alopecic) region. Moreover, sebaceous glands were larger in the frontal alopecic region than in the occipital region. These larger glands may be associated with other dermatological pathologies, such as seborrhoeic dermatitis.

Extra- and intramuscular nerves distributions of the triceps surae muscle as a basis for muscle resection and botulinum toxin injections

PURPOSE

To compare the distribution of extramuscular nerve branches with their intramuscular ramifications in the triceps surae muscle, thus providing anatomical substantiation for the topography of muscle resection and botulinum toxin injections.

METHODS

Dissection and modified Sihler's staining of 18 whole-mount human cadaveric specimens.

RESULTS

The distance between the areas with the highest extramuscular branch density and the area of densest intramuscular arborization in gastrocnemius and soleus muscles is approximately 10% of the calf length. This finding should be taken into consideration during nerve blocking and botulinum toxin injections for the treatment of spasticity. Intramuscular nerve arborization patterns make it possible to outline neuromuscular segments in the gastrocnemius and soleus muscles.

CONCLUSIONS

Surgical or therapeutic interventions in areas of high extramuscular and intramuscular nerve density can increase the efficacy and safety of botulinum toxin injections and neurotomy. Intramuscular nerve branching patterns should be taken into consideration during triceps surae resection.

Asymmetry of the palpebral fissure and upper eyelid crease in Koreans

The purpose of the present study was to quantify the asymmetry of the palpebral fissure (PF) and upper eyelid crease in normal Koreans. Photographs were taken of 273 males and 321 females aged from 20 to 49 years with a standard head position and eyes open. We investigated the presence of asymmetries of the PF inclination (PFI), PF height (PFH), PF width (PFW) and the upper eyelid crease. The criteria for asymmetry were 2 degrees for PFI, 1mm for PFH and 3mm for PFW. The PFH was larger on the right side than on the left side, whereas the PFW was larger on the left than on the right. The prevalence of asymmetry of the PFI, PFH and PFW was 22.3%, 24.2% and 18.3% in males, and 35.8%, 26.5% and 18.7% in females, respectively. In most cases of PF asymmetry, the PFH was larger on the right and the PFW was larger on the left. A left-only upper eyelid crease was more common than a right-only upper eyelid crease in both sexes. The asymmetry of the PF was generally more common in females.

Anatomical and radiological study of the superior and inferior gluteal arteries in the gluteus maximus muscle for musculocutaneous flap in Koreans

The position, distribution pattern, and perforating branch of the superior gluteal artery (SGA) and the inferior gluteal artery (IGA) in the gluteus maximus muscle (GMM) were investigated through fine dissection and the radiological method. The SGA was located at about the upper one-third of the posterior superior iliac spine (PSIS)-greater trochanter of the femur (GT) line and medially at about 1cm from the line. The IGA was located at around the middle point of the PSIS-ischial tuberosity (IT) line. The perforating branches passed through the muscle to the subcutaneous tissue and were distributed to the GMM that divided the upper and lower parts; the SGA supplied to the upper two-fifths of the GMM; and the IGA supplied to the rest of the muscle. The course of the SGA and the IGA in the GMM were classified into four types according to their distribution patterns, and the most common type was the typical type whereby the IGA supplied an area larger than the SGA. These results were somewhat different from previous studies, but these differences must be considered for a safe and effective flap procedure.

Branching patterns of the arterial branches supplying the middle vascular pedicle of the sternocleidomastoid muscle: a topographic anatomical study with surgical applications for the use of pedicles osteomuscular flaps

When making a sternocleidomastoid (SCM) osteomuscular flap to include the clavicle and determining the rotation arc of the osteomuscular flap, it is very important to know the location and the origin of the superior thyroid artery and the distribution pattern of the SCM branch. Accordingly, in this study, the 50 SCM muscles and their arteries were dissected in 26 Korean cadavers, and the results were analyzed. The average distances from the origin of the superior thyroid artery to the clavicular and sternal heads of the SCM muscle were 87.6 mm (57.7-123.8 mm) and 131.2 mm (99.7-166.8 mm), respectively. The average distance from the origin of the superior thyroid artery to the SCM branch entering the SCM muscle was 30.1 mm (16.0-37.7 mm). After entering the SCM muscle, the SCM branches of the superior thyroid artery bifurcated into the clavicular and sternal branches at a point located an average of 58.8 mm (28.4-130.4 mm) above the clavicle. The distribution patterns of the superior thyroid artery were classified into six types based on the branching order and the dual supplies to the SCM muscle. Among them, type I in which the laryngeal branch first divided from the superior thyroid artery was the most common case (36%).

Biochemistry and reproductive endocrinology of estrogen sulfotransferase

Estrogen sulfotransferase is a cytosolic enzyme that catalyzes the sulfoconjugation and inactivation of estrogens. Significant progress has been made in the last few years regarding the structure, substrate specificity, tissue expression, and regulation of mammalian estrogen sulfotransferases. The enzyme has high affinity for estrogens and is expressed in a number of estrogen target tissues, including the male and female reproductive systems. Expression of the enzyme in the testis has been particularly well characterized. In the testis, estrogen sulfotransferase is localized selectively to Leydig cells and its expression in these cells is dependent on LH and androgen. It was concluded, from both in vitro and in vivo studies, that estrogen sulfotransferase can function as an effective modulator of local estrogen activity in target tissues. The finding that certain hydroxylated polychlorinated biphenyls are potent inhibitors of the human estrogen sulfotransferase enzyme raises the possibility that environmental chemicals can cause endocrine disruption by enhancing endogenous estrogen activity through inhibition of steroid transformation enzymes such as estrogen sulfotransferase. This provides a new paradigm in explaining the endocrine disrupting potential of environmental chemicals that have low or no binding affinities for steroid hormone receptors.

Targeted disruption of the mouse estrogen sulfotransferase gene reveals a role of estrogen metabolism in intracrine and paracrine estrogen regulation

Elicitation of biological responses by estrogen in target tissues requires the presence of ER as well as receptor-active ligand in the local microenvironment. Though much attention has been devoted to the study of the receptor in estrogen target tissues, the concept is emerging that tissue estrogen sensitivity may also be regulated by ligand availability through metabolic transformation in situ. Here, we show that targeted disruption, in the mouse, of an estrogen metabolic enzyme, estrogen sulfotransferase (EST), causes structural and functional lesions in the male reproductive system. EST catalyzes the sulfoconjugation and inactivation of estrogen and is expressed abundantly in testicular Leydig cells. Although knockout males were fertile and phenotypically normal initially, they developed age-dependent Leydig cell hypertrophy/hyperplasia and seminiferous tubule damage. Development of these lesions in the testis could be recapitulated by exogenous E2 administration in younger knockout mice, suggesting that they arose in older knockout mice from chronic estrogen stimulation. Older knockout mice were also found to have reduced testis and epididymis weights but increased seminal vesicle/coagulating gland weight because of tissue swelling. Furthermore, total and forward sperm motility of older knockout mice was reduced by 60% and 80%, respectively, and these mice produced smaller litters compared with age-matched wild-type males. These findings establish a role for EST in the male reproductive system and indicate that intracrine and paracrine estrogen activity can be modulated by a ligand transformation enzyme under a physiological setting. Thus, inhibition of estrogen metabolic enzymes by environmental chemicals, as has been demonstrated recently for the human EST, may constitute a novel mechanism of endocrine disruption in vivo.

Characterization of glycosylphosphatidylinositol-anchored decay accelerating factor (GPI-DAF) and transmembrane DAF gene expression in wild-type and GPI-DAF gene knockout mice using polyclonal and monoclonal antibodies with dual or single specificity

Decay-accelerating factor (DAF, CD55) is a glycosylphosphatidylinositol (GPI)-linked membrane inhibitor of complement activation. While human and other mammalian species contain only one DAF gene, two distinct DAF genes, referred to as GPI-DAF and transmembrane (TM)-DAF, respectively, have been identified in the mouse. Using several independently generated monoclonal and polyclonal antibodies, either with dual or single specificity for GPI-DAF and TM-DAF gene products, we have examined the expression of the two DAF genes in tissues of the wild-type and a strain of knockout mouse whose GPI-DAF gene has been inactivated. By fluorescence-activated cell sorting (FACS) analysis, we found that DAF protein is present on the wild-type mouse erythrocytes and lymphocytes but no signal was detectable on the same cells of GPI-DAF gene knockout mice. Both T and B lymphocytes and splenic macrophages express the GPI-DAF gene but the expression level is higher on B lymphocytes than on T lymphocytes. Within the T cell population, both CD4+ and CD8+ T cells are positive. DAF protein was detected by immunohistochemistry at high levels on wild-type mouse spermatids and mature sperm. In contrast, only mature sperm stained positive in the GPI-DAF gene knockout mouse testis, suggesting that GPI-DAF but not the TM-DAF gene is expressed on spermatids. Examination of the fetoplacental unit at the day 7.5 stage revealed that GPI-DAF but not the TM-DAF gene is expressed in the maternal decidua cells surrounding the trophoectoderm of the embryo. No DAF expression was detected on trophoblast or the embryo proper. These findings suggest that although the TM-DAF gene is irrelevant on mouse blood cells, the two DAF genes may have different roles in germ cell development and/or mature sperm function. Because complement receptor 1-related gene/protein y (Crry) has been shown to be expressed on early mouse embryos, the complete lack of GPI-DAF and TM-DAF gene expression in early mouse development may explain the observed sensitivity of Crry-deficient embryos to maternal complement attack.

Increased susceptibility of decay-accelerating factor deficient mice to anti-glomerular basement membrane glomerulonephritis

To prevent complement-mediated autologous tissue damage, host cells express a number of membrane-bound complement inhibitors. Decay-accelerating factor (DAF, CD55) is a GPI-linked membrane complement regulator that is widely expressed in mammalian tissues including the kidney. DAF inhibits the C3 convertase of both the classical and alternative pathways. Although DAF deficiency contributes to the human hematological syndrome paroxysmal nocturnal hemoglobinuria, the relevance of DAF in autoimmune tissue damage such as immune glomerulonephritis remains to be determined. In this study, we have investigated the susceptibility of knockout mice that are deficient in GPI-anchored DAF to nephrotoxic serum nephritis. Injection of a subnephritogenic dose of rabbit anti-mouse glomerular basement membrane serum induced glomerular disease in DAF knockout mice but not in wild-type controls. When examined at 8 days after anti-glomerular basement membrane treatment, DAF knockout mice had a much higher percentage of diseased glomeruli than wild-type mice (68.8 +/- 25.0 vs 10.0 +/- 3.5%; p < 0.01). Morphologically, DAF knockout mice displayed increased glomerular volume (516 +/- 68 vs 325 +/- 18 x 10(3) microm(3) per glomerulus; p < 0.0001) and cellularity (47.1 +/- 8.9 vs 32.0 +/- 3.1 cells per glomerulus; p < 0.01). Although the blood urea nitrogen level showed no difference between the two groups, proteinuria was observed in the knockout mice but not in the wild-type mice (1.4 +/- 0.7 vs 0.02 +/- 0.01 mg/24 h albumin excretion). The morphological and functional abnormalities in the knockout mouse kidney were associated with evidence of increased complement activation in the glomeruli. These results support the conclusion that membrane C3 convertase inhibitors like DAF play a protective role in complement-mediated immune glomerular damage in vivo.

Genomic structure, functional comparison, and tissue distribution of mouse Cd59a and Cd59b

CD59 is a crucial complement regulatory protein that inhibits the terminal step of the complement activation cascade by interfering with the binding of C9 to C5b-8, thus preventing the formation of the membrane attack complex (MAC). We recently reported that the mouse genome contains two Cd59 genes, while the human and rat genomes each contain only one Cd59 gene (Qian et al. 2000). Here, we describe the genomic structure, comparative activity, and tissue distribution of these two mouse genes, designated Cd59a and Cd59b. The mouse Cd59 genes encompass a total of 45.6 kb with each gene having four exons. Cd59a spans 19 kb, and Cd59b spans 15 kb, with approximately 11.6 kb of genomic DNA separating the two genes. The overall sequence similarity between Cd59a and Cd59b is approximately 60%. The sequence similarity between exon 2, exon 3, and exon 4 and the respective flanking regions between the two genes is over 85%, but exon 1 and its flanking regions are totally different. Comparative studies of the activity of both genes as inhibitors of MAC formation revealed that Cd59b has a specific activity that is six times higher than that of Cd59a. Using polyclonal antibodies specific to either Cd59a or Cd59b, we showed that Cd59a and Cd59b are both widely expressed in the kidneys, brain, lungs, spleen, and testis, as well as in the blood vessels of most mouse tissues. Interestingly, testicular Cd59a appeared to be expressed exclusively in spermatids, whereas Cd59b was expressed in more mature sperm cells. These results suggest that even though Cd59a and Cd59b are expressed in multiple tissues, they may play some different roles, particularly in reproduction.

Membrane complement regulatory proteins: insight from animal studies and relevance to human diseases

The complement system plays an important role in host defense. However, if not properly regulated, activated complement can also cause significant damage to host tissues. To prevent complement-mediated autologous tissue damage, host cells express a number of membrane-bound complement regulatory proteins. These include decay-accelerating factor (DAF, CD55), membrane cofactor protein (MCP, CD46) and CD59. Recent studies of membrane complement regulatory proteins from various animal species have revealed similarities as well as significant differences from the corresponding human proteins. In this review, we summarize recent advances in this area and contrast the structure, function and tissue distribution of membrane complement regulatory proteins in human and nonprimate mammalian species. We also discuss how the characterization of the animal proteins has provided important clues and might continue to show relevance to the pathogenesis and therapeutics of a number of human diseases.

Glutathione stimulates sulfated estrogen transport by multidrug resistance protein 1

Multidrug resistance protein 1 (MRP1) is an ATP-binding cassette (ABC) transporter that transports a range of hydrophobic xenobiotics, as well as relatively hydrophilic organic anion conjugates. The protein is present at high levels in testicular Leydig and Sertoli cells. Studies with knockout mice suggest that MRP1 may protect germ cells from exposure to some cytotoxic xenobiotics, but potential endobiotic substrates in this organ have not been identified. Previously, we have shown certain D-ring, but not A-ring, estrogen glucuronides can act as competitive inhibitors of MRP1 mediated transport, suggesting that they are potential substrates for the protein. In the case of 17 beta-estradiol-17 beta-d-glucuronide, this has been confirmed by direct transport studies. The Leydig cell is the major site of estrogen conjugation in the testis. However, the principal products of conjugation are A-ring estrogen sulfates, which are then effluxed from the cell by an unknown transporter. To determine whether MRP1/mrp1 could fulfill this function, we used membrane vesicles from MRP1-transfected HeLa cells to assess this possibility. We found that estradiol and estrone 3-sulfate alone were poor competitors of MRP1-mediated transport of the cysteinyl leukotriene, leukotriene C(4). However, in the presence of reduced glutathione (GSH), their inhibitory potency was markedly increased. Direct transport studies using [(3)H]estrone 3-sulfate confirmed that the conjugated estrogen could be efficiently transported (K(m) = 0.73 microm, V(max) = 440 pmol mg(-)1 protein min(-)1), but only in the presence of either GSH or the nonreducing alkyl derivative, S-methyl GSH. In contrast to previous studies using vincristine as a substrate, we detected no reciprocal increase in MRP1-mediated GSH transport. These results provide the first example of GSH-stimulated, MRP1-mediated transport of a potential endogenous substrate and expand the range of MRP1 substrates whose transport is stimulated by GSH to include certain hydrophilic conjugated endobiotics, in addition to previously identified hydrophobic xenobiotics.

Identification and functional characterization of a new gene encoding the mouse terminal complement inhibitor CD59

CD59 is a 18- to 20-kDa, GPI-anchored membrane protein that functions as a key regulator of the terminal step of the complement activation cascade. It restricts binding of C9 to the C5b-8 complex, thereby preventing the formation of the membrane attack complex (C5b-9 of complement). A single human CD59 gene has been identified, and corresponding genetic homologues from rat, mouse, and pig have been characterized in previous studies. In this study, we report the discovery and functional characterization of a separate cd59 gene in the mouse (referred to as cd59b, the previously characterized mouse cd59 gene as cd59a). Mouse cd59b is 85% and 63% identical to cd59a at the nucleotide and amino acid level, respectively. In cDNA transfection experiments with Chinese hamster ovary cells, peptide-tagged cd59b was detected on the cell surface by flow cytometry and was shown to be susceptible to phosphatidylinositol-specific phospholipase C cleavage. Chinese hamster ovary cells expressing cd59b were significantly more resistant than control cells to human and mouse complement-mediated lysis. These results suggest that cd59b encodes a GPI-anchored protein that is functionally active as a membrane attack complex inhibitor. Northern blot analysis revealed that cd59b is expressed selectively in the mouse testis. In contrast, the major transcript of cd59a was shown to be expressed at high levels in the heart, kidney, liver, and lung, but only minimally in the testis. These results revealed the existence of two distinct cd59 genes in the mouse that are differentially regulated and that may have nonoverlapping physiological functions in vivo.

Correlation between PAP-dependent steroid binding activity and substrate specificity of mouse and human estrogen sulfotransferases

Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes the sulfoconjugation and inactivation of estrogens using 3'-phosphoadenosine-5'-phosphosulfate (PAPS) as an activated sulfate donor. A finding of undetermined significance in the study of EST has been that the guinea pig EST is able to bind pregnenolone and estradiol with high affinity in the presence of PAP, the reaction by-product of the sulfate donor PAPS. This finding has raised the possibility that EST may have other physiological functions independent of its enzymatic activity as a sulfotransferase. To determine if the PAP-dependent steroid binding activity is a common property shared by other estrogen sulfotransferases, we have expressed the mouse and human EST in bacteria and used the purified protein to address this question. We found that, in the presence of PAP, both recombinant mouse and human EST were able to bind estradiol with high affinity but only the human EST was able to bind pregnenolone. In addition, we show that human but not the mouse EST was also able to bind dehydroepiandrosterone, a property that was not described for the guinea pig EST. Furthermore, we demonstrate that the promiscuity of human EST in steroid binding is mirrored by a correspondingly low substrate specificity in its enzymatic activity as a sulfotransferase. Reversely, the lack of stable binding of pregnenolone and dehydroepiandrosterone by the mouse EST is paralleled by a lack of sulfotransferase activity of this enzyme toward these two steroids. Mutagenesis of mouse EST within a domain critical for PAPS binding abolished both its sulfotransferase and PAP-dependent estrogen binding activity. These data suggest that stable binding of steroids such as pregnenolone or estrogen is not an independent property of estrogen sulfotransferases but rather is related to their catalytic activity.

Structural characterization of mouse CD97 and study of its specific interaction with the murine decay-accelerating factor (DAF, CD55)

CD97 is a newly identified, activation-associated human leucocyte antigen with seven putative transmembrane domains. It has an extended extracellular segment containing several adhesion molecule structure motifs, and has been shown to interact with the human complement regulator, decay-accelerating factor (DAF, CD55). To understand further the interaction between CD97 and DAF, as well as the structure and function of CD97 in general, we have cloned the mouse CD97 cDNA and studied the encoded protein for its membrane association property and ability to interact specifically with the murine decay-accelerating factor. The full-length mouse CD97 cDNA that we have cloned and characterized encodes a protein that is 60% identical to the three epidermal growth factor (EGF) domain-containing form of human CD97 but does not contain the Arg-Gly-Asp (RGD) motif which is present in human CD97. Two other alternatively spliced forms of mouse CD97 were also identified. These forms differ by the number of EGF-like sequence repeats present in the N-terminal region. Northern blot analysis revealed that CD97 is expressed widely in mouse tissues and in resting as well as activated cultured mouse splenocytes. Transient transfection of human embryonic kidney (HEK) 293 cells with the mouse CD97 cDNA in a green-fluorescence protein vector (pEGFP-N1) showed plasma membrane targeting of the expressed protein. Western blot analysis confirmed its membrane association and identified the existence of a processed C-terminal fragment, supporting the notion that CD97 on the cell membrane is composed of post-translationally generated subunits. Adhesion studies demonstrated that normal, but not DAF knockout mouse erythrocytes and splenocytes adhered to mouse CD97-transfected HEK cells. The interaction of CD97 and DAF was found to be species-restrictive in that human erythrocytes were unable to bind to mouse CD97-transfected HEK cells. These results indicate that the general structure, membrane association property and DAF-binding ability of CD97 are conserved and that the adhesive interaction between CD97 and DAF is independent of the RGD motif. The finding that CD97 is distributed widely among various mouse tissues suggests that CD97 may have other roles beyond lymphocyte activation.

Regulation of estrogen sulfotransferase expression in Leydig cells by cyclic adenosine 3',5'-monophosphate and androgen

Estrogen sulfotransferase (EST) catalyzes the specific sulfonation and inactivation of estrogens. A common site for EST expression in mammalian species is the testicular Leydig cells. In previous in vivo studies, we have shown that testicular expression of EST is under the regulation of LH. Thus, EST expression in mouse Leydig cells was abolished by hypophysectomy, but could be restored by hCG injection. In this study, we have evaluated the downstream mechanisms by which LH exerts its regulatory effect on EST. Primary mouse Leydig cells were isolated and purified by collagenase digestion and Percoll density gradient centrifugation. They were cultured in serum-free medium at 32 C and treated with various agents for 24 or 48 h, and levels of EST messenger RNA and enzyme activity were determined. Consistent with the in vivo data suggesting an essential role of LH in regulating EST expression, treatment of primary mouse Leydig cells in vitro with 100 microM 8-bromo-dibutyryl cAMP [(Bu)2cAMP] increased EST expression 3- to 5-fold. The effect of (Bu)2cAMP was attenuated by the steroidogenesis inhibitor aminoglutethimide and was mimicked by the potent androgen 5alpha-dihydrotestosterone (5-DHT). The activity of 5-DHT in stimulating EST expression was blocked by the androgen receptor antagonist, hydroxyflutamide. These data suggested the involvement of androgen in (Bu)2cAMP-induced EST expression. Further evidence came from the study with interleukin-1beta, another agent known to suppress Leydig cell steroidogenesis by down-regulating P450c17 gene expression. Treatment of Leydig cells with 0.2 ng/ml interleukin-1beta inhibited (Bu)2cAMP-induced EST expression, which was overcome by the addition of 5-DHT. Finally, in the testis-feminized mouse (Tfm) in which the androgen receptor is nonfunctional due to a frameshift mutation, testicular EST expression is completely absent, whereas messenger RNAs of steroidogenic enzymes such as P450c17 and 3beta-hydroxysteroid dehydrogenase are relatively abundant. We conclude that, by acting as an autocrine or paracrine factor, androgen plays an essential role in the regulation of estrogen sulfotransferase expression in Leydig cell by LH and cAMP.

Role of decay-accelerating factor in regulating complement activation on the erythrocyte surface as revealed by gene targeting

Decay-accelerating factor (DAF) is a glycosylphosphatidylinositol (GPI)-anchored membrane protein that inhibits both the classical and the alternative pathways of complement activation. DAF has been studied extensively in humans under two clinical settings: when absent from the erythrocytes of paroxysmal nocturnal hemoglobinuria (PNH) patients, who suffer from complement-mediated hemolytic anemia, and in transgenic pigs expressing human DAF, which have been developed to help overcome complement-mediated hyperacute rejection in xenotransplantation. Nevertheless, the exact role of DAF in regulating complement activation in vivo on the cell surface and the species specificity of this molecule remain to be fully characterized. To address these issues, we have used gene targeting to produce mice lacking GPI-anchored DAF. We found that erythrocytes from mice deficient in GPI-anchored DAF showed no increase in spontaneous complement activation in vivo but exhibited impaired regulation of zymosan-initiated bystander and antibody-triggered classical pathway complement activation in vitro, resulting in enhanced complement deposition. Despite a high level of C3 fixation, no homologous hemolysis occurred. It is noteworthy that GPI-linked DAF knockout erythrocytes, when tested with human and guinea pig sera, were more susceptible to heterologous complement lysis than were normal erythrocytes. These results suggest that DAF is capable of regulating homologous as well as heterologous complement activation via the alternative or the classical pathway. They also indicate that DAF deficiency alone is not sufficient to cause homologous hemolysis. In contrast, when the assembly of the membrane-attack complex is not properly regulated, as in the case of heterologous complement activation or in PNH patients, impaired erythrocyte DAF activity and enhanced C3 deposition could lead to increased hemolytic reaction.

Early isotonic saline resuscitation from uncontrolled hemorrhage in rats

BACKGROUND

Attempts to modify traditional fluid resuscitation have been based on animal models that evaluate several variables including anesthesia. This study presents the effects of early saline resuscitation from severe uncontrolled hemorrhage unanesthetized rats.

METHODS

Sixty-three female Sprague-Dawley rats were equally divided into three groups: group A, nonresuscitated; and groups B and C, resuscitated ;with isotonic saline (40 and 80 mL/kg, respectively). Hemodynamics, blood loss, survival time, and mortality were recorded for 360 minutes after the hemorrhage, which was initiated by 75% resection of the tail.

RESULTS

In group C, 80 mL/kg of saline significantly lowered mortality (24% vs 76% and 71% for groups A and B, respectively) with concomitant increases in mean survival time (241 +/- 103 min vs 146 +/- 108 and 175 +/- 92 min for groups A and B, respectively). There were no statistically significant differences in blood loss, hematocrit, or hemodynamic parameters among the groups.

CONCLUSIONS

Early and adequate isotonic saline resuscitation of unanesthetized rats improved outcome despite continuing hemorrhage. The significantly lower mortality rate and increased survival time were not a result of transiently improved arterial pressure and did not correlate with blood loss. No significant bleeding increases were noted in the resuscitated groups.

Expression of estrogen sulfotransferase in MCF-7 cells by cDNA transfection suppresses the estrogen response: potential role of the enzyme in regulating estrogen-dependent growth of breast epithelial cells

Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes the sulfonation of estrogens at the 3-hydroxyl position by use of 3'-phosphoadenosine-5'-phosphosulfate as an activated sulfate donor. Although largely known and studied as a phase II metabolic enzyme with prominent expression in the liver, the high substrate specificity of EST (with a high Vmax/Km value for estrogen) suggests that expression of the enzyme in extrahepatic, estrogen target tissues, such as the breast epithelium, may constitute an effective mechanism for local estrogen regulation as well. In this study, we have evaluated the physiological significance of EST expression by cDNA transfection studies with use of the estrogen-dependent MCF-7 breast cancer cell line as a model system. We show that expression of EST in MCF-7 cells effectively reduces the cells' response to physiological concentrations of estradiol (10 nM) by up to 70% as determined in an estrogen-responsive reporter gene assay. In addition, we demonstrate that expression of EST similarly inhibits estrogen-stimulated DNA synthesis and cell proliferation by 21% and 46%, respectively. (The thymidine incorporation rate was measured 3 days after and the cell numbers were counted 8 days after transfection.) These results provide direct evidence for the functional significance of in situ EST expression in the breast epithelium and suggest that abnormal regulation of the enzyme may have pathological implications in the development and maintenance of hormone-dependent breast carcinomas.

Estrogen sulfotransferase expression in the human liver: marked interindividual variation and lack of gender specificity

Estrogen sulfotransferase (EST) catalyzes the specific sulfonation of estrogen at the 3'-hydroxyl position using 3'-phosphoadenosine-5'-phosphosulfate as an activated sulfate donor. Sulfonation renders the hormone biologically inactive as well as changing its half-life within the human body. Studies in the rat and mouse have suggested that expression of EST in the liver is age- and sex-dependent, being prominent only in sexually mature young males. Although a human EST cDNA has previously been cloned, the characteristics of hepatic EST expression in human subjects remain to be defined. In this study, we have investigated and compared the expression of EST in 10 human liver samples by using an EST-specific antibody and performing enzyme activity assays. We found a marked interindividual variation (up to 25-fold) in the hepatic expression of EST. However, EST protein level in the human liver is correlated neither with gender nor with age. Interestingly, paired-group analysis revealed a statistically significant difference in the hepatic expression of EST protein and activity between alcohol users and nonusers. We conclude that, unlike what is observed in the rodent liver, EST expression in the human liver is not sex-limited. Thus hepatic EST may play a role in estrogen metabolism and homeostasis in both genders of human subjects. The marked individual variation suggests that EST gene expression is subject to sensitive control by genetic or environmental factors. The potential correlation between alcohol consumption and hepatic EST expression deserves further evaluation.

Mouse steroid sulfotransferases: substrate specificity and preliminary X-ray crystallographic analysis

Three mouse cytosolic sulfotransferases were expressed in Escherichia coli cells in order to study their substrate specificities toward natural as well as synthetic steroid hormones. The Km and Vmax values confirmed the high substrate specificity of estrogen and hydroxysteroid sulfotransferases toward estradiol and dehydroepiandrosterone, respectively. In sharp contrast, the synthetic estrogen diethylstilbestrol was metabolized efficiently by both enzymes to its disulfate ester. These sulfotransferases display highly stereospecific sulfotransferase activity for sulfating only the trans-isomer of diethylstilbestrol. Crystals suitable for high-resolution structure determination of estrogen sulfotransferase were grown with polyethylene glycol. The crystals belong to the orthorhombic space group P2(1)2(1)2, and diffracted to 2.5 A.

Cellular localization and regulation of expression of testicular estrogen sulfotransferase

Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes the specific sulfonation of estrogens at the 3-hydroxyl position using 3'-phosphoadenosine-5'-phosphosulfate as an activated sulfate donor. Sulfated estrogens no longer bind to the estrogen receptor and are, therefore, hormonally inactive. Although liver has been considered a primary site for steroid sulfotransferase activities, we previously have cloned the mouse EST complementary DNA and found the enzyme to be expressed abundantly in the testis of normal mice. In this study we show by reverse transcription-PCR that EST is also expressed in the testes of rat and man, suggesting that testicular expression of EST may be a common phenomenon among different species. Using a purified polyclonal antibody raised against the bacterially expressed mouse EST protein, we demonstrate by immunohistochemistry that EST is localized selectively to the androgen-producing Leydig cells within the mouse testis. Additionally, we show that Leydig cell expression of EST is under the control of the pituitary hormone LH and is regulated differentially during development. In contrast to the high level of expression in mature intact animals, EST is not present in Leydig cells of hypophysectomized mice or in Leydig cells of fetal and prepubertal (day 5 or 17) mouse testes. Administration of hCG to hypophysectomized mice restored the testicular expression of EST. Together, these results suggest that testicular expression of EST may play an important role in male reproduction, conceivably by modulating the activity of locally synthesized estrogen in the testis of a sexually mature animal.

Mouse decay-accelerating factor: selective and tissue-specific induction by estrogen of the gene encoding the glycosylphosphatidylinositol-anchored form

Neonatal exposure of mice to estrogen (diethylstilbestrol) results in a high incidence (90%) of uterine tumor later in life. In an effort to screen for estrogen-regulated genes in the uterus of the neonatal mouse, we have isolated a murine homologue of the human decay-accelerating factor (DAF), a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein and a member of the regulators of complement activation family of proteins that function to prevent autologous complement-mediated tissue damage. The induced mouse DAF cDNA has a 64% sequence identity with the human counterpart at the nucleotide level and a 50% identity in the deduced amino acid sequence. It consists of 390 amino acids and contains four short consensus repeats of internal homology characteristic of human DAF. It also contains a hydrophobic C-terminal that most likely serves as a signal for GPI anchor attachment. Sequence comparison with the recently reported mouse DAF cDNAs confirmed that the estrogen-inducible gene corresponds to the mouse GPI DAF gene. The induction of mouse DAF by estrogen is tissue specific and can be mimicked by the antiestrogen tamoxifen. Furthermore, the regulation of uterine DAF expression by estrogen is limited to the GPI DAF gene. The transmembrane DAF gene is not expressed in the mouse uterus, either with or without estrogen stimulation. These results suggest that the two mouse DAF genes are differentially regulated, and that the GPI-anchored DAF may play important roles in estrogen responses and other physiologic or pathophysiologic processes of the female reproductive system.

Mouse decay-accelerating factor: selective and tissue-specific induction by estrogen of the gene encoding the glycosylphosphatidylinositol-anchored form

Neonatal exposure of mice to estrogen (diethylstilbestrol) results in a high incidence (90%) of uterine tumor later in life. In an effort to screen for estrogen-regulated genes in the uterus of the neonatal mouse, we have isolated a murine homologue of the human decay-accelerating factor (DAF), a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein and a member of the regulators of complement activation family of proteins that function to prevent autologous complement-mediated tissue damage. The induced mouse DAF cDNA has a 64% sequence identity with the human counterpart at the nucleotide level and a 50% identity in the deduced amino acid sequence. It consists of 390 amino acids and contains four short consensus repeats of internal homology characteristic of human DAF. It also contains a hydrophobic C-terminal that most likely serves as a signal for GPI anchor attachment. Sequence comparison with the recently reported mouse DAF cDNAs confirmed that the estrogen-inducible gene corresponds to the mouse GPI DAF gene. The induction of mouse DAF by estrogen is tissue specific and can be mimicked by the antiestrogen tamoxifen. Furthermore, the regulation of uterine DAF expression by estrogen is limited to the GPI DAF gene. The transmembrane DAF gene is not expressed in the mouse uterus, either with or without estrogen stimulation. These results suggest that the two mouse DAF genes are differentially regulated, and that the GPI-anchored DAF may play important roles in estrogen responses and other physiologic or pathophysiologic processes of the female reproductive system.

Molecular characterization of a testis-specific estrogen sulfotransferase and aberrant liver expression in obese and diabetogenic C57BL/KsJ-db/db mice

Sulfation represents a major pathway for the inactivation of steroid hormones such as estrogens and is catalyzed by a group of enzymes called sulfotransferases. Aberrant regulation of an estrogen sulfotransferase has been demonstrated previously in the livers of obese and diabetogenic C57BL/KsJ-db/db strain mice. In this paper, we report the molecular cloning and functional characterization of a full-length complementary DNA for estrogen sulfotransferase from mouse testis. The mouse estrogen sulfotransferase complementary DNA encodes 295 amino acids. It shares 88%, 77%, 75%, and 68% identity in amino acid sequence with the rat liver, human liver, guinea pig adrenal, and bovine placental estrogen sulfotransferase, respectively. The mouse enzyme was expressed as a glutathione-S-transferase fusion protein in Escherichia coli. The fusion protein was affinity purified, and milligram quantities of pure enzyme were obtained after cleavage of the fusion protein with thrombin. The expressed enzyme exhibits a high substrate specificity toward estrogens, including estradiol and estrone. Neither dehydroepiandrosterone, pregnenolone, testosterone, nor a simple phenolic compound, 4-nitrophenol appears to be a substrate. Northern hybridization indicates that messenger RNA (1.3 kilobases) for the estrogen sulfotransferase is expressed exclusively in the testes in control C57BL/KsJ mice. However, both the messenger RNA and protein are dramatically induced in the livers of obese and diabetogenic C57BL/KsJ-db/db mice. In contrast to the liver, the constitutive expression of the enzyme in the testis is not affected by the db/db genotype. These results recapitulate the species-specific nature in the tissue distribution of estrogen sulfotransferase and suggest complex regulatory mechanisms in its expression under normal and pathophysiological conditions.

Molecular cloning of an allene oxide synthase: a cytochrome P450 specialized for the metabolism of fatty acid hydroperoxides

Allene oxide synthases convert lipoxygenase-derived fatty acid hydroperoxides to unstable allene epoxides. In plants, an allene oxide is a precursor of the growth regulator jasmonic acid. Previously, we showed that an allene oxide synthase from flaxseed has the spectral properties of a cytochrome P450. The relationship to the P450 gene family is now established from the primary structure deduced from the cDNA. The encoded protein of 536 amino acids has segments at the C terminus that match certain well conserved regions in cytochrome P450s. The heme-binding cysteine is recognizable at position 489. However, there are unprecedented modifications in this region, with substitution of two of the three most highly conserved amino acids. Also very unusual is the absence of a conserved threonine that normally helps form the O2-binding pocket in cytochrome P450s. Notably, O2 is not involved in the allene oxide synthase reaction and, furthermore, the enzyme is known to have a weak interaction with CO. While allene oxide synthases are usually described as microsomal, the flax cDNA encodes a 58-amino acid signal sequence characteristic of a mitochondrial or chloroplast transit peptide. Therefore, the enzyme is a type I P450 and most likely is located in chloroplasts. Overall, the flax allene oxide synthase has < or = 25% identity to other P450s; it belongs to a newly discovered gene family, to be designated CYP74. The flaxseed enzyme is prototypical of this family of enzymes that remain to be characterized in plants and animals.

Formation of epoxyalcohols by a purified allene oxide synthase. Implications for the mechanism of allene oxide synthesis

The allene oxide synthase (hydroperoxide dehydrase) of flaxseed is a cytochrome P450 that exhibits an exceptionally high catalytic turnover (> or = 1000/s) for hydroperoxy substrates. In a previous study, using a crude extract of flaxseed, we detected a secondary activity that could offer an insight into the mechanism of the enzymatic transformation of hydroperoxides. We observed that the substrate 8R-hydroxy-15S-hydroperoxyeicosa-5,9,11,13,17-pentaenoic acid is converted not only to allene oxide, but also to epoxyalcohol derivatives (Brash, A. R., Baertschi, S. W., and Harris, T. M. (1990) J. Biol. Chem. 265, 6705-6712). The transformation of hydroperoxides to epoxyalcohols has been investigated extensively in other systems, and heterolytic or homolytic cleavage of the hydroperoxide is associated with characteristic rearrangements and stereochemistry of the epoxyalcohol products. Using the purified enzyme, we established that the epoxyalcohols are products of the allene oxide synthase. Their structures were determined by UV, gas chromatography-mass spectrometry, and NMR. The major epoxyalcohol is 8R,13R-dihydroxy-14R,15S-epoxyeicosa-5Z,9E ,11Z,17Z-tetraenoic acid, a trans-epoxide with an alpha-hydroxyl in the relative threo configuration. Two minor products are the corresponding 11E isomer and a cis-epoxide identified as 8R,13-dihydroxy-14S,15S-epoxyeicosa-5Z,9E,11E,++ +17Z-tetraenoic acid. Gas chromatography-mass spectrometry analysis of a reaction with [18O2]hydroperoxide substrate indicated complete retention of the hydroperoxy oxygens in the epoxyalcohol products. Mechanistic precedents support a homolytic hydroperoxide cleavage as the initial step in the synthesis of these epoxyalcohols. We suggest that the same process initiates allene oxide synthesis, a conclusion that is also most compatible with the known chemistry of cytochromes P450.

Allene oxide and aldehyde biosynthesis in starfish oocytes

Allene oxides are a very unusual type of epoxide that, in biological systems, are formed by the enzymic dehydration of fatty acid hydroperoxides (lipoxygenase products). This reaction occurs widely in plants, in which allene oxide synthesis is a key step in the conversion of linolenic acid to jasmonic acid, the plant growth regulator. We report biosynthesis of the allene oxide (8R)-8,9-epoxyeicosa-(5Z,9,11Z,14Z)-tetraenoic acid via the (8R)-lipoxygenase metabolism of arachidonic acid in starfish oocytes. Formation of the allene oxide was deduced from high pressure liquid chromatography, UV, gas chromatography-mass spectrometry and 1H-NMR analyses of the precise structure and mechanism of biosynthesis of its major hydrolysis product, the alpha-ketol 8-hydroxy-9-ketoeicosa-(5Z,11Z,14Z)-trienoic acid. A second enzymic activity detected in the oocytes (hydroperoxide lyase) cleaves specifically the (8R)-hydroperoxy substrate into C7 and C13 fragments, identified as the hydroxyacid, (5Z)-7-hydroxyheptenoic acid, and two aldehydes, (2E,4Z,7Z)-tridecenal and its 4E isomer. Discovery of the allene oxide synthase and hydroperoxide lyase marks the first definitive localization of these enzymic activities to an animal cell. It was established previously that the (8R)-lipoxygenase metabolite (8R)-HETE will activate the maturation (re-initiation of meiosis) of starfish oocytes. The individual 8-lipoxygenase products may be involved at distinct stages of cell development.

Investigation of the allene oxide pathway in the coral Plexaura homomalla: formation of novel ketols and isomers of prostaglandin A2 from 15-hydroxyeicosatetraenoic acid

Prostaglandin A2 is a major constituent of the gorgonian Plexaura homomalla, and there is evidence that its biosynthesis involves a noncyclooxygenase pathway. The coral contains an 8(R)-lipoxygenase and an allene oxide synthase; from arachidonic acid, the sequential action of these enzymes gives an allene epoxide, the cyclization of which forms an analogue of prostaglandin A2 (PGA2) with no 15-hydroxyl group. In this study we examined the metabolic fate of 15-hydroxyeicosatetraenoic acid (15-HETE), which via analogous reactions could lead to PGA2. The 8(R)-lipoxygenase metabolized preferentially the 15(R) enantiomer of 15-HETE, and this reaction was stimulated fivefold by including 1 M NaCl in the incubation. Further enzymic steps were detected by comparing the metabolic profiles of the 8(R)-hydroperoxy-15(R)-hydroxy intermediate with that of its 8(S),15(S) enantiomer. Two main products were formed exclusively from the 8(R),15(R) enantiomer: an allene epoxide and the comparatively stable epoxide, 8,9-epoxy-10,15-dihydroxyeicosa-5,11,14-trienoic acid. Formation of the allene oxide was inferred from detection of its hydrolysis and cyclization products. It cyclized to give two isomers of PGA2 which have a "cis" arrangement of the side chains. The main hydrolysis product (8,15-dihydroxy-9-ketoeicosa-5,11,13-trienoic acid) was unstable and prone to oxygenation, giving 8,14,15-trihydroxy-9-ketoeicosa-5,10,12-trienoic acids after reduction of the 14-hydroperoxide. We conclude that metabolism of a 15-hydroxy eicosanoid is a potential route to the A series prostaglandins, although the low yield and lack of stereochemical control suggest that this is not the natural pathway of biosynthesis in P. homomalla. Unexpectedly, the major end products of the pathway are trihydroxy ketols and the single diastereomer of a stable epoxyalcohol.

Purification of an allene oxide synthase and identification of the enzyme as a cytochrome P-450

Fatty acid hydroperoxides (lipoxygenase products) are metabolized to allene oxides by a type of dehydrase that has been detected in plants, corals, and starfish oocytes. The allene oxides are unstable epoxide precursors of more complex products such as jasmonic acid, the plant growth hormone. Characterization of the dehydrase enzyme of flaxseed revealed that it is a 55-kilodalton hemoprotein. The spectral characteristics of this dehydrase revealed it to be a cytochrome P-450. It operates with the remarkable activity of greater than or equal to 1000 turnovers per second. The results establish a new catalytic activity for a cytochrome P-450 and illustrate the cooperation of different oxygenases in pathways of fatty acid metabolism.

Identification of novel hydroxy fatty acids in the barnacle Balanus balanoides

The ability of the barnacle Balanus balanoides tissues to produce eicosanoid hatching factors from endogenous polyunsaturated fatty acids has been investigated. GC-MS analysis of an active HPLC fraction from the trihydroxy fatty acid band on TLC revealed the presence of a number of trihydroxy fatty acids and two compounds which were tentatively identified as chlorinated dihydroxy fatty acids. The identified trihydroxy fatty acids are 10,11,12-trihydroxy-5,8,14-eicosatrienoic acid, 10,11,12-trihydroxy-5,8,14,17-eicosatetraenoic acid, 13,14,15-trihydroxy-5,8,11,17-eicosatetraenoic acid and 12,13,14-trihydroxy-4,7,10,16,19-docosapentaenoic acid. The tentatively identified chlorinated dihydroxy fatty acids are 9-chloro- and/or 11-chloro-8,12-dihydroxyeicosatetraenoic acid. The formation of these compounds is evidence of lipoxygenase activities in Balanus balanoides and their identification will facilitate the understanding of the roles eicosanoids play in barnacle physiology, especially with regard to the larval hatching process.