The calcified amorphous layer of the skin of Bufo marinus (Amphibia: Anura)

The integument of Bufo marinus is surveyed. It is similar to that of other anurans and contains the three chromatophores common to anurans. The skin of these toads contains more than 28% minerals deposited as small crystals in a mucopolysaccharide-positive amorphous layer between the stratum compactum and the stratum spongiosum. These crystals reveal a high content of calcium and phosphorus aggregated in and near membrane-bound vesicles which have an appearance very similar to matrix vesicles. Electron microscopy gives the appearance that these vesicles are associated with flbroblasts located between alternating bundles of collagen. Histochemical studies indicate that the amorphous layer possesses many of the characteristics commonly associated with mineralized cartilage or bone.     

似鲇高原鳅皮肤与鳍的组织学观察

采用石蜡切片技术及H.E和AB-PAS染色方法,对似鲇高原鳅(Triplophysa siluroides)头部、腹部、背部、侧线部和尾部皮肤结构及胸鳍、腹鳍、背鳍、臀鳍和尾鳍的组织结构进行观察。各部位皮肤均由表皮和真皮构成,真皮包括疏松层和致密层,不同部位皮肤厚度不同。表皮层腹部最厚,为(84.62±10.82)μm,侧线部最薄,为(14.97±3.95)μm,各部位表皮厚度差异显著。表皮层分布着黏液细胞、棒状细胞及味蕾。疏松层头部最厚,为(282.71±70.56)μm,尾部最薄,为(29.07±4.88)μm,该层分布有黑色素细胞、空泡状细胞和颗粒腺,而黏液腺分布于致密层。各部位的鳍均由表皮层、胶原纤维层、胶原下层及鳍条构成,表皮层与皮肤表皮层组成相似,鳍条是矿化的结缔组织。     

Caudal fin in the white shark, Carcharodon carcharias (Lamnidae): a dynamic propeller for fast, efficient swimming

The caudal peduncle and caudal fin of Carcharodon carcharias together form a dynamic locomotory structure. The caudal peduncle is a highly modified, dorsoventrally compressed and rigid structure that facilitates the oscillations of the caudal fin. Its stiffness appears to be principally achieved by a thick layer of adipose tissue ranging from 28-37% of its cross-sectional area, reinforced by cross-woven collagen fibers. Numerous overlying layers of collagen fibers of the stratum compactum, oriented in steep left- and right-handed helices (approximately 65 degrees to the shark's long axis), prevent bowstringing of the perimysial fibers, which lie just below the dermal layer. Perimysial fibers, muscles, and the notochord are restricted to the dorsal lobe of the caudal fin and comprise the bulk of its mass. Adipose tissue reinforces the leading edge of the dorsal lobe of the caudal fin and contributes to maintaining the ideal cross-sectional geometry required of an advanced hydrofoil. Most of the mass of the ventral lobe consists of the ceratotrichia or fin rays separated by thin partitions of connective tissue. Dermal fibers of the stratum compactum of the dorsal lobe occur in numerous distinct layers. The layers are more complex than in other sharks and appear to reflect a hierarchical development in C. carcharias. The fiber layer comprises a number of thick fiber bundles along the height of the layer and the layers get thicker deeper into the stratum compactum. Each of these layers alternates with a layer a single fiber-bundle deep, a formation thought to give stability to the stratum compactum and to enable freer movements of the fiber system. In tangential sections of the stratum compactum the fiber bundles in the dorsal lobe can be seen oriented with respect to the long axis of the shark at approximately 55-60 degrees in left- and right-handed helices. Because of the backward sweep of the dorsal lobe (approximately 55 degrees to the shark's long axis) the right-handed fibers also parallel the lobe's long axis. In the dorsal lobe, ceratotrichia are present only along the leading edge (embedded within connective tissue), apparently as reinforcement. Stratum compactum fiber bundles of the ventral lobe, viewed in transverse section, lack the well-ordered distinctive layers of the dorsal lobe, but rather occur as irregularly arranged masses of tightly compacted fiber bundles of various sizes. In tangential sections the fiber bundles are oriented at angles of approximately 60 degrees, generally in one direction, i.e., lacking the left- and right-handed helical pattern. Tensile load tests on the caudal fin indicate high passive resistance to bending by the skin. The shear modulus G showed that the skin's contribution to stiffness (average values from three specimens at radians 0.52 and 1.05) is 33.5% for the dorsal lobe and 41.8% for the ventral. The load tests also indicate greater bending stiffness of the ventral lobe compared to the dorsal. Overall, the anatomy and mechanics of the dorsal lobe of C. carcharias facilitate greater control of movement compared to the ventral lobe. The helical fiber architecture near the surface of the caudal fin is analogous to strengthening of a thin cylinder in engineering. High fiber angles along the span of the dorsal lobe are considered ideal for resisting the bending stresses that the lobe is subjected to during the locomotory beat cycle. They are also ideal for storing strain energy during bending of the lobe and consequently may be of value in facilitating the recovery stroke. The complex fiber architecture of the caudal fin and caudal peduncle of C. carcharias provides considerable potential for an elastic mechanism in the animal's swimming motions and consequently for energy conservation.     

The musculotendinous system of an anguilliform swimmer: Muscles, myosepta, dermis, and their interconnections in Anguilla rostrata

Eel locomotion is considered typical of the anguilliform swimming mode of elongate fishes and has received substantial attention from various perspectives such as swimming kinematics, hydrodynamics, muscle physiology, and computational modeling. In contrast to the extensive knowledge of swimming mechanics, there is limited knowledge of the internal body morphology, including the body components that contribute to this function. In this study, we conduct a morphological analysis of the collagenous connective tissue system, i.e., the myosepta and skin, and of the red muscle fibers that sustain steady swimming, focusing on the interconnections between these systems, such as the muscle-tendon and myosepta-skin connections. Our aim is twofold: (1) to identify the morphological features that distinguish this anguilliform swimmer from subcarangiform and carangiform swimmers, and (2) to reveal possible pathways of muscular force transmission by the connective tissue in eels. To detect gradual morphological changes along the trunk we investigated anterior (0.4L), midbody (0.6L), and posterior body positions (0.75L) using microdissections, histology, and three-dimensional reconstructions. We find that eel myosepta have a mediolaterally oriented tendon in each the epaxial and hypaxial regions (epineural or epipleural tendon) and two longitudinally oriented tendons (myorhabdoid and lateral). The latter two are relatively short (4.5-5% of body length) and remain uniform along a rostrocaudal gradient. The skin and its connections were additionally analyzed using scanning electron microscopy (SEM). The stratum compactum of the dermis consists of approximately 30 layers of highly ordered collagen fibers of alternating caudodorsal and caudoventral direction, with fiber angles of 60.51 +/- 7.05 degrees (n = 30) and 57.58 +/- 6.92 degrees (n = 30), respectively. Myosepta insert into the collagenous dermis via fiber bundles that pass through the loose connective tissue of the stratum spongiosum of the dermis and either weave into the layers of the stratum compactum (weaving fiber bundles) or traverse the stratum compactum (transverse fiber bundles). These fiber bundles are evenly distributed along the insertion line of the myoseptum. Red muscles insert into lateral and myorhabdoid myoseptal tendons but not into the horizontal septum or dermis. Thus, red muscle forces might be distributed along these tendons but will only be delivered indirectly into the dermis and horizontal septum. The myosepta-dermis connections, however, appear to be too slack for efficient force transmission and collagenous connections between the myosepta and the horizontal septum are at obtuse angles, a morphology that appears inadequate for efficient force transmission. Though the main modes of undulatory locomotion (anguilliform, subcarangiform, and carangiform) have recently been shown to be very similar with respect to their midline kinematics, we are able to distinguish two morphological classes with respect to the shape and tendon architecture of myosepta. Eels are similar to subcarangiform swimmers (e.g., trout) but are substantially different from carangiform swimmers (e.g., mackerel). This information, in addition to data from kinematic and hydrodynamic studies of swimming, shows that features other than midline kinematics (e.g., wake patterns, muscle activation patterns, and morphology) might be better for describing the different swimming modes of fishes.     

SD大鼠皮肤组织病理学观察

目的观察不同日龄SD大鼠皮肤组织学结构。方法10％甲醛固定,行石蜡切片,HE染色。结果新生大鼠皮肤较薄,透明层缺乏,皮脂腺发育良好。6月龄时表皮、真皮和皮下组织明显增厚,毛囊增粗,生长旺盛,毛囊深入皮下脂肪层。24月龄时,大鼠皮脂腺及汗腺萎缩,表皮变薄,真皮成纤维细胞、血管数量减少,弹力纤维变细。结论不同日龄SD大鼠皮肤组织学结构有差异。     

Negative potential level in the outer layer of the toad skin.

The isolated skin of the toad Bufo marinus ictericus when impaled from the outer surface by glass microelectrodes filled with 3 M KCl shows a voltage profile which is a continuous function of the depth of impalement. The superficial intraepithelial potential difference measured with reference to the external solution (PDi) is negative with NaCl-Ringer's solution on both sides of the skin, displaying a minimum of -26.7+/-3.6 mV at 6+/-2 mum. Null value is obtained at 19+/-3 mum, with positive values for deeper impalements. Indications of cell impalements (abrupt voltage and resistance jumps) were frequently observed at sites deeper than 25 mum from the outer surface. Measurements of the electrical resistance between the microelectrode and the external solution, made with single- and double-barreled microelectrodes, showed great discrepancies, which may be attributed to distinct pathways of different resistances in the stratum corneum. PDi measured at a depth of 5 mum was a logarithmic function of Na2SO4 or K2SO4 concentration in the external solution, increasing in negativity with a reduction in concentration. Substitution of Na by K in the external solution had only minor effects on PDi. Acidification of the external solution from pH 9 is accompanied by a reduction in the negative value of PDi. At pH 3 PDi was positive. PDi was interpreted as a diffusion potential at the tip of the microelectrode due to KCl diffusion from the electrode into the matrix of the stratum corneum. Differences in K and Cl mobilities, responsible for the origin of PDi, were attributed to fixed charges in the matrix of the stratum corneum, with density and polarity determined by their degree of proponation, controlled by the hydrogen ion concentration of the external solution. Skin potential, short-circuit current and their relationship to PDI were discussed.     

Effects of the sheep-chewing louse (Damalinia ovis) on the epidermis of the Australian merino

Frozen longitudinal skin sections taken from the dorsal thoraco-lumbar region of adult Merino sheep that were infested with the sheep-chewing louse were examined by light microscopy. The epidermis of infested sheep exhibited acanthosis due to hyperplasia of the stratum spinosum, and orthokeratosis. The thickness of the uncornified epidermis, the stratum corneum, and the sudanophilic region were significantly greater (P less than 0.005) than equivalent regions in louse-free Merinos and the results suggest that a positive correlation exists between the thickness of each region and the level of louse infestation. The results indicate that the variance in region thickness was greater in lousy than in louse-free sheep (P less than 0.005).     

角蟾亚科3物种皮肤的组织学观察

应用石蜡切片和H.E染色技术,对角蟾亚科3个属的代表物种:短肢异角蟾(Xenophrys brachykolos)、宽头短腿蟾(Brachytarsophrys carinense)和小口拟角蟾(Ophryophryne microstoma)的皮肤进行了组织学观察及参数测量比较。分别取头背、体背和体腹3个部位的皮肤进行观察。结果表明,3物种的皮肤基本结构相似,均由表皮和真皮组成,真皮包括疏松层和致密层,疏松层中有大量腺体分布,包括黏液腺和颗粒腺2种。皮肤厚度、各组织层相对厚度以及腺体密度之间存在种间差异和部位差异。在宽头短腿蟾背部皮肤中,发现了与尖吻山角蟾(Megophrys nasuta)皮肤中一种片层状、H.E染色呈蓝色的皮肤真皮骨化结构(osteoderms)很相似的结构;短肢异角蟾皮肤中有明显的钙化层结构,小口拟角蟾皮肤钙化程度较弱。皮肤的骨化和钙化可能具有防止水分流失,抵御干燥的功能。2种内骨骼在角蟾亚科中同时存在,为探讨两栖动物皮肤内骨骼的进化提供了重要的研究基础。     

The kinetics of transdermal ethanol exchange.

The kinetics of ethanol transport from the blood to the skin surface are incompletely understood. We present a mathematical model to predict the transient exchange of ethanol across the skin while it is being absorbed from the gut and eliminated from the body. The model simulates the behavior of a commercial device that is used to estimate the blood alcohol concentration (BAC). During the elimination phase, the stratum corneum of the skin has a higher ethanol concentration than the blood. We studied the effect of varying the maximum BAC and the absorption rate from the gut on the relationship between BAC and equivalent concentration in the gas phase above the skin. The results showed that the ethanol concentration in the gas compartment always took longer to reach its maximum, had a lower maximum, and had a slower apparent elimination rate than the BAC. These effects increased as the maximum BAC increased. Our model's predictions are consistent with experimental data from the literature. We performed a sensitivity analysis (using Latin hypercube sampling) to identify and rank the importance of parameters. The analysis showed that outputs were sensitive to solubility and diffusivity within the stratum corneum, to stratum corneum thickness, and to the volume of gas in the sampling chamber above the skin. We conclude that ethanol transport through the skin is primarily governed by the washin and washout of ethanol through the stratum corneum. The dynamics can be highly variable from subject to subject because of variability in the physical properties of the stratum corneum.     

The mechanical properties of stratum corneum. I. The effect of water and ambient temperature on the tensile properties of newborn rat stratum corneum.

The tensile properties of the outermost layer of skin of neonatal rats, the stratum corneum, were investigated at a constant strain rate as a function of moisture content and ambient test temperature. The results show that the mechnical behavior of this membrane, whose primary constituent is the fibrous protein keratin, can be significantly altered by variations in both the sorbed water content and ambient temperature. In particular, a brittle to ductile transition was observed at 25 degrees C once the hydration level exceeded 70% relative humidity. Similarly, an identical phenomenon was detected at temperatures beyond 40 degrees C for specimens whose equilibrium moisture concentrations were maintained at 10 g H2 O/100 g dry protein. Differential scanning calrimetry measurements showed the presence of a molecular relaxation process which migrated from 42 degrees C at 40% relative humidity to --18 degrees C at 95% relative humidity. It is postulated that this relaxation process, possibly corresponding to the glass transition of the fibrous protein component of stratum corneum, is primarily responsible for the observed behavior.     

The mechanical properties of stratum corneum: I. The effect of water and ambient temperature on the tensile properties of newborn rat stratum corneum

The tensile properties of the outermost layer of skin of neonatal rats, the stratum corneum, were investigated at a constant strain rate as a function of moisture content and ambient test temperature. The results show that the mechanical behavior of this membrane, whose primary constituent is the fibrous protein keratin, can be significantly altered by variations in both the sorbed water content and ambient temperature. In particular, a brittle to ductile transition was observed at 25°C once the hydration level exceeded 70% relative humidity. Similarly, an identical phenomenon moisture concentrations were maintained at 10 g H₂O/100 g dry protein. Differential scanning calorimetry measurements showed the presence of a molecular relaxation process which migrated from 42°C at 40% relative humidity to −18°C at 95% relative humidity. It is postulated that this relaxation process, possibly corresponding to the glass transition of the fibrous protein component of stratum corneum, is primarily respnsible for the observed behavior.     

Methodology to determine failure characteristics of planar soft tissues using a dynamic tensile test

Predicting the injury risk in automotive collisions requires accurate knowledge of human tissues, more particularly their mechanical properties under dynamic loadings. The present methodology aims to determine the failure characteristics of planar soft tissues such as skin, hollow organs and large vessel walls. This consists of a dynamic tensile test, which implies high-testing velocities close to those in automotive collisions. To proceed, I-shaped tissue samples are subjected to dynamic tensile tests using a customized tensile device based on the drop test principle. Data acquisition has especially been adapted to heterogeneous and soft biological tissues given that standard measurement systems (considered to be global) have been completed with a non-contact and full-field strain measurement (considered to be local). This local measurement technique, called the Image Correlation Method (ICM) provides an accurate strain analysis by revealing strain concentrations and avoids damaging the tissue. The methodology has first been applied to human forehead skin and can be further expanded to other planar soft tissues. The failure characteristics for the skin in terms of ultimate stress are 3 MPa +/- 1.5 MPa. The ultimate global longitudinal strains are equal to 9.5%+/-1.9% (Green-Lagrange strain), which contrasts with the ultimate local longitudinal strain values of 24.0%+/-5.3% (Green-Lagrange strain). This difference is a consequence of the tissue heterogeneity, clearly illustrated by the heterogeneous distribution of the local strain field. All data will assist in developing the tissue constitutive law that will be implemented in finite element models.     

The skin structure of greater rhea (Rheidae,Palaeognathae)

The aim of this study was to describe the histological structure of the skin of greater rhea (Rhea americana), a ratite bird native to South America. Skin samples were taken from three regions of the trunk (alar, dorsal and pelvic) in 14 specimens which ages ranged from 7 days to adulthood. Serial sections were obtained and subjected to different staining procedures (haematoxylin and eosin, orcein, Masson's trichrome and Gomori), and a morphometric analysis was carried out on stained slides. In general, both epidermis and dermis showed increased thickness of its layers with age. Some differences between regions can be detected both in epidermis and in dermis; for example in adults and 7‐day‐old birds, the stratum corneum of the alar region was thicker than of the dorsal region. In general, the skin of greater rhea was similar to that described in ratites and other birds (a thin epidermis compared to dermis, dermis with scarce elastic fibres, a slender and vascularized stratum superficiale, collagen fibres arranged in three directions). The scarcity of elastic fibres and the general cross‐weaved arrangement of the collagen fibres in the dermis of the adult greater rhea provide strength and flexibility to the dermis, two important features in leather industry.     

Finite element analysis for transverse carpal ligament tensile strain and carpal arch area

Mechanics of carpal tunnel soft tissue, such as fat, muscle and transverse carpal ligament (TCL), around the median nerve may render the median nerve vulnerable to compression neuropathy. The purpose of this study was to understand the roles of carpal tunnel soft tissue mechanical properties and intratunnel pressure on the TCL tensile strain and carpal arch area (CAA) using finite element analysis (FEA). Manual segmentation of the thenar muscles, skin, fat, TCL, hamate bone, and trapezium bone in the transverse plane at distal carpal tunnel were obtained from B-mode ultrasound images of one cadaveric hand. Sensitivity analyses were conducted to examine the dependence of TCL tensile strain and CAA on TCL elastic modulus (0.125–10 MPa volar-dorsally; 1.375–110 MPa transversely), skin-fat and thenar muscle initial shear modulus (1.6–160 kPa for skin-fat; 0.425–42.5 kPa for muscle), and intratunnel pressure (60–480 mmHg). Predictions of TCL tensile strain under different intratunnel pressures were validated with the experimental data obtained on the same cadaveric hand. Results showed that skin, fat and muscles had little effect on the TCL tensile strain and CAA changes. However, TCL tensile strain and CAA increased with decreased elastic modulus of TCL and increased intratunnel pressure. The TCL tensile strain and CAA increased linearly with increased pressure while increased exponentially with decreased elastic modulus of TCL. Softening the TCL by decreasing the elastic modulus may be an alternative clinical approach to carpal tunnel expansion to accommodate elevated intratunnel pressure and alleviate median nerve compression neuropathy.     

Regulation of Epithelial Na+ Permeability by Protein Kinase C is Tissue Specific

Protein kinase C (PKC) is a major regulator of a broad range of cellular functions. Activation of PKC has been reported to stimulate Na⁺ transport across frog skin epithelium by increasing the apical Na⁺ permeability. This positive natriferic response has not been observed with other epithelial preparations, and could reflect the specific experimental conditions of different laboratories, or species or organ specificity of the response to PKC. In the present study, measurements were conducted with skins and urinary bladders from the same animals of two different species. The PKC activator TPA uniformly increased the transepithelial Na⁺ transport (measured as amiloride-sensitive short-circuit current, I _SC, across skins from Rana temporaria and Bufo marinus, and inhibited I _SC across bladders from the same animals. Inhibitors of PKC (staurosporine, H-7 and chelerythrine) partially blocked the TPA-induced stimulation of I _SC across frog skin. The specificity of the PKC response by amphibian skin could have reflected an induction of moulting, similar to that observed with aldosterone. However, light micrographs of paired areas of frog skin revealed no evidence of the putative moulting. Separation of stratum corneum from the underlying stratum granulosum could be detected following application of aldosterone. We conclude that the effect of PKC on epithelial Na⁺ channels is organ, and not species specific. The stimulation of Na⁺ permeability in amphibian skin does not arise from sloughing of the stratum corneum. These observations are consistent with the hypothesis that the natriferic action arises from the calcium-independent isozyme of PKC previously detected in frog skin. Received: 19 January 1996/Revised: 10 April 1996     

Biosynthetic pathways of filaggrin and loricrin--two major proteins expressed by terminally differentiated epidermal keratinocytes

We have used immunoelectron microscopy to map the biosynthetic pathways of loricrin and filaggrin in epidermal keratinocytes at successive stages of differentiation in newborn mouse skin. The filaggrin epitope is first detected in large, irregularly shaped, keratohyalin granules (F-granules) in the stratum granulosum, and then distributed throughout the cytoplasms of the innermost layers of stratum corneum cells. We conclude that the poly-protein filaggrin precursor is first accumulated in F-granules, from which it is subsequently released and processed into filaggrin, and becomes associated with the densely packed bundles of keratin filaments inside stratum corneum cells. Its diminished visibility in the outer layers correlates with the known degradation of filaggrin to free amino acids. Loricrin is first detected in small round keratohyalin granules (L-granules), and subsequently at the periphery of cells throughout the stratum corneum. Labeling of purified keratinocyte envelopes establishes that this loricrin epitope is exposed only at their inner (cytoplasmic) surface. Thus loricrin is initially accumulated in L-granules, to be released at a specifically programmed stage of keratinocyte maturation, and incorporated into the covalently cross-linked lining of the cell envelope. Since loricrin is rich in cysteine, L-granules account for the sulfur-rich keratohyalin granules described earlier. Proposals are made to rationalize why, subsequent to synthesis, filaggrin precursor and loricrin should be segregated both from each other and from the rest of the cytoplasm.     

The mechanical properties of hydrated intermediate filaments: insights from hagfish slime threads

Intermediate filaments (IFs) impart mechanical integrity to cells, yet IF mechanics are poorly understood. It is assumed that IFs in cells are as stiff as hard alpha-keratin, F-actin, and microtubules, but the high bending flexibility of IFs and the low stiffness of soft alpha-keratins suggest that hydrated IFs may be quite soft. To test this hypothesis, we measured the tensile mechanics of the keratin-like threads from hagfish slime, which are an ideal model for exploring the mechanics of IF bundles and IFs because they consist of tightly packed and aligned IFs. Tensile tests suggest that hydrated IF bundles possess low initial stiffness (E(i) = 6.4 MPa) and remarkable elasticity (up to strains of 0.34), which we attribute to soft elastomeric IF protein terminal domains in series with stiffer coiled coils. The high tensile strength (180 MPa) and toughness (130 MJ/m(3)) of IF bundles support the notion that IFs lend mechanical integrity to cells. Their long-range elasticity suggests that IFs may also allow cells to recover from large deformations. X-ray diffraction and congo-red staining indicate that post-yield deformation leads to an irreversible alpha-->beta conformational transition in IFs, which leads to plastic deformation, and may be used by cells as a mechanosensory cue.     

Comparison of rat epidermal keratinocyte organotypic culture (ROC) with intact human skin: lipid composition and thermal phase behavior of the stratum corneum.

The present report is a part of our continuing efforts to explore the utility of the rat epidermal keratinocyte organotypic culture (ROC) as an alternative model to human skin in transdermal drug delivery and skin irritation studies of new chemical entities and formulations. The aim of the present study was to compare the stratum corneum lipid content of ROC with the corresponding material from human skin. The lipid composition was determined by thin-layer chromatography (TLC) and mass-spectrometry, and the thermal phase transitions of stratum corneum were studied by differential scanning calorimetry (DSC). All major lipid classes of the stratum corneum were present in ROC in a similar ratio as found in human stratum corneum. Compared to human skin, the level of non-hydroxyacid-sphingosine ceramide (NS) was increased in ROC, while alpha-hydroxyacid-phytosphingosine ceramide (AP) and non-hydroxyacid-phytosphingosine ceramides (NP) were absent. Also some alterations in fatty acid profiles of ROC ceramides were noted, e.g., esterified omega-hydroxyacid-sphingosine contained increased levels of oleic acid instead of linoleic acid. The fraction of lipids covalently bound to corneocyte proteins was distinctly lower in ROC compared to human skin, in agreement with the results from DSC. ROC underwent a lipid lamellar order to disorder transition (T2) at a slightly lower temperature (68 degrees C) than human skin (74 degrees C). These differences in stratum corneum lipid composition and the thermal phase transitions may explain the minor differences previously observed in drug permeation between ROC and human skin.     

Complete genome sequence of Staphylothermus marinus Stetter and Fiala 1986 type strain F1

Staphylothermus marinus Fiala and Stetter 1986 belongs to the order Desulfurococcales within the archaeal phylum Crenarchaeota. S. marinus is a hyperthermophilic, sulfur-dependent, anaerobic heterotroph. Strain F1 was isolated from geothermally heated sediments at Vulcano, Italy, but S. marinus has also been isolated from a hydrothermal vent on the East Pacific Rise. We report the complete genome of S. marinus strain F1, the type strain of the species. This is the fifth reported complete genome sequence from the order Desulfurococcales.