Whorl-like outer segments in the retina of the mole (Scalopus aquaticus)

The retina of the common mole, Scalopus aquaticus, has been studied with the transmission electron microscope. Structures examined include: pigment epithelium, outer and inner segments of the sensory cells, and synaptic ribbons of the outer plexiform layer. Rods and cones described in species by previous light microscopic studies are not seen with electron microscopic techniques. Instead, the mole retina contains peculiar outer segments consisting of whorls of membranes. These whorls have some similarities to dystrophic retinas of several vertebrates. The possibility of their being caused by extraordinary light exposure is discussed, also. The appearance of the sensory cells suggests that they are functional receptors.     

Morphogenesis of the fetal membranes of an American mole, Scalopus aquaticus.

Scalopus membranes are characterized by: Superficial nidation; antimesometrial orientation of the embryonic disc; amniogenesis by folding; an extensive but transitory choriovitelline placenta; a large yolk sac with late and incomplete inversion; large persistent allantoic vesicle; a very broad, thin, villous, epitheliochorial chorioallantoic placenta of annular shape interrupted mesometrially, dotted with numerous areolae, and bordered by a nonvillous sparsely vascular chorioallantoic membrane connected with the persistent bilaminar omphalopleure by a very narrow rim of chorion. There is no decidua. Electron microscopy shows that at 8 mm, CR, (limb bud embryo) the uterine epithelium of the interhemal membrane may be 0.5 micron or less in thickness, but that it shows no signs of degeneration. Trophoblastic microvilli often penetrate the epithelium to within 0.2 micron of its base. At this time there is active secretion by the uterine glands, and cellular hypertrophy and cytolysis of the epithelium at the gland mouths, with active phagocytosis by the areolar cytotrophoblast. The occurrence of absorptive areolae in an insectivore emphasizes the probable primitiveness of this widely distributed placental mechanism. In spite of similarities of the yolk sac to that of rabbits and rodents, the bilaminar omphalopleure produces no invasive trophoblastic giant cells. The definitive membranes of Parascalops breweri and Scapanus latimanus are like those of Scalopus. The placentae of Talpa europaea, Condylura cristata, and Neurotrichus gibbsii are discoid and relatively much smaller, thicker and more complex in internal structure. There is some reason to believe that the fetal membrane systems of moles and shrews (Soricoidea) are more like those of the ancestral mammalian stock than are those of any other recent eutherians.     

Age determination, age structure, and longevity in the mole Scalopus aquaticus (Mammalia: Insectivora)

Three hundred and eighty-two moles, Scalopus aquaticus , were collected from 16 sampling grids located within a 23 km² area in South Carolina, USA. Age of moles was determined using tooth wear. Both the mean and median ages of trapped moles were c. two years; the oldest mole was in its seventh year of life. More than 50% of the individuals are estimated to die during the first six months of life; adult survivorship was relatively high and age-dependent. There was differential mortality between the sexes, and females lived longer than males. Scalopus aquaticus in South Carolina lived c. 1.2 times longer than the maximum lifespan predicted on the basis of body mass. Pooled samples of moles yielded the expected age distribution, with fewer individuals occurring in successively older age classes. However, based on bootstrap estimates of the variance in age structure, samples from some grids contained significantly more young or old individuals than expected due to sampling error. Mole populations appear not to be in demographic equilibrium at this local scale, but instead conform more closely to a metapopulation-type of structure.     

Muscle architecture and out‐force potential of the thoracic limb in the eastern mole (Scalopus aquaticus)

Moles have modified thoracic limbs with hypertrophied pectoral girdle muscles that allow them to apply remarkably high lateral out‐forces during the power stroke when burrowing. To further understand the high force capabilities of mole forelimbs, architectural properties of the thoracic limb muscles were quantified in the Eastern mole (Scalopus aquaticus). Architectural properties measured included muscle mass, moment arm, belly length, fascicle length, and pennation angle, and these were used to provide estimates of maximum isometric force, joint torque, and power. Measurements of muscle moment arms and limb lever lengths were additionally used to analyze the out‐force contributions of the major pectoral girdle muscles. Most muscles have relatively long fascicles and little‐to‐no pennation. The humeral abductor/rotators as a functional group are massive and are capable of relatively high force, power, and joint torque. Of this group, the bipennate m. teres major is the most massive and has the capacity to produce the highest force and joint torque to abduct and axially rotate the humerus. In general, the distal limb muscles are relatively small, but have the capacity for high force and mechanical work by fascicle shortening. The muscle architectural properties of the elbow extensors (e.g., m. triceps brachii) and carpal flexors (e.g., m. palmaris longus) are consistent with the function of these muscles to augment lateral out‐force application. The humeral abductor/rotators m. latissimus dorsi, m. teres major, m. pectoralis, and m. subscapularis are calculated to contribute 13.9 N to out‐force during the power stroke, and this force is applied in a ‘frontal’ plane causing abduction of the humerus about the sternoclavicular joint. Moles have several specializations of their digging apparatus that greatly enhance the application of out‐force, and these morphological features suggest convergence on limb form and burrowing function between New and Old World moles. J. Morphol. 274:1277–1287, 2013. © 2013 Wiley Periodicals, Inc.     

Skin surface lipids of the mink

Skin surface lipids from mink (Mustela vison) were collected in acetone and analyzed by thin-layer chromatography and gas chromatography. The principal components were wax monoesters (92%), cholesteryl esters (5%), free fatty acids (1%), fatty alcohols (1%) and cholesterol (1%). The fatty acids and alcohols contained in these lipids were composed principally of homologous series of straight chained omega 7-unsaturated structures (C16-C24), accompanied by lesser proportions of homologous series of saturated (C14-C22) and omega 9-unsaturated (C18-C22) structures.     

Coccidian parasites (Apicomplexa: Eimeriidae) from insectivores. VI. Six new species from the eastern mole, Scalopus aquaticus

Thirteen eastern moles, Scalopus aquaticus, collected in West Texas were examined for coccidian oocysts; 11 (85%) were infected and eight (73%) of these had multiple infections representing two or more species. One cyclosporan, three eimerians, and two isosporans were studied and all are described as new species. Sporulated oocysts of Cyclospora megacephali n. sp. were subspheroidal, 18.5 X 15.7 (14-21 X 12-18) microns; they had sporocysts pointed at one end with Stieda bodies nearly as wide as the sporocysts themselves, and were 15.0 X 7.2 (11-17 X 6-9) microns; C. megacephali was found in four (31%) hosts. Sporulated oocysts of Eimeria scalopi n. sp. were spheroidal to subspheroidal, 13.6 X 12.6 (11-17 X 11-15) microns with sporocysts lemon-shaped, 8.7 X 5.5 (7-10 X 4-7) microns; it was found in six (46%) hosts. Sporulated oocysts of Eimeria aquatici n. sp. were asymmetrically ellipsoidal, 17.0 X 10.6 (14-20 X 9-14) microns with sporocysts elongately ovoidal, 9.0 X 5.2 (8-11 X 4-6) microns; it was found in two (15%) hosts. Sporulated oocysts of Eimeria motleiensis n. sp. were subspheroidal, 17.0 X 15.3 (15-20 X 13-18) microns with sporocysts ovoidal, 10.7 X 6.8 (10-13 X 6-8) microns; it was found in seven (54%) hosts. Sporulated oocysts of Isospora motleiensis n. sp. were spheroidal to subspheroidal, 13.6 X 12.0 (10-17 X 8-15) microns with sporocysts broadly ovoidal, 9.5 X 6.7 (7-11 X 4-8) microns; it was found in nine (69%) hosts. Sporulated oocysts of Isospora aquatici n. sp. were subspheroidal, 20.9 X 18.4 (15-24 X 13-21) microns with sporocysts ellipsoidal, 11.8 X 9.0 (9-14 X 7-11) microns; it was found in two (15%) hosts.     

Genetic variation in a subterranean mammal, Scalopus aquaticus (Insectivora: Talpidae)

Allozyme variation was examined for 382 moles (Scalopus aquaticus) collected from 16 localities located within a 23 km² area in South Carolina, U.S.A. Of 26 presumptive loci that were scored for all moles, 8 (30.8%) were observed to be polymorphic. Mean direct-count heterozygosity was 7.2%, c. 75% higher than the mean value reported for mammals. The findings of this study do not support the hypothesis that more purely subterranean species of mammals will exhibit levels of allozyme variation lower than those of above-ground species.     

Coccidian Parasites (Apicomplexa: Eimeriidae) from Insectivores. VI. Six New Species from the Eastern Mole,Scalopus aquaticus1

ABSTRACT Thirteen eastern moles, Scalopus aquaticus, collected in West Texas were examined for coccidian oocysts; 11 (85%) were infected and eight (73%) of these had multiple infections representing two or more species. One cyclosporan, three eimerians, and two isosporans were studied and all are described as new species. Sporulated oocysts of Cyclospora megacephali n. sp. were subspheroidal, 18.5 × 15.7 (14–21 × 12–18) μm; they had sporocysts pointed at one end with Stieda bodies nearly as wide as the sporocysts themselves, and were 15.0 × 7.2 (11–17 × 6–9) μm; C. megacephali was found in four (31%) hosts. Sporulated oocysts of Eimeria scalopi n. sp. were spheroidal to subspheroidal, 13.6 × 12.6 (11–17 × 11–15) μm with sporocysts lemon-shaped, 8.7 × 5.5 (7–10 × 4–7) μm; it was found in six (46%) hosts. Sporulated oocysts of Eimeria aquatici n. sp. were asymmetrically ellipsoidal, 17.0 × 10.6 (14–20 × 9–14) μm, with sporocysts elongately ovoidal, 9.0 × 5.2 (8–11 × 4–6) μm; it was found in two (15%) hosts. Sporulated oocysts of Eimeria motleiensis n. sp. were subspheroidal, 17.0 × 15.3 (15–20 × 13–18) μm with sporocysts ovoidal, 10.7 × 6.8 (10–13 × 6–8) μm; it was found in seven (54%) hosts. Sporulated oocysts of Isospora motleiensis n. sp. were spheroidal to subspheroidal, 13.6 × 12.0 (10–17 × 8–15) μm with sporocysts broadly ovoidal, 9.5 × 6.7 (7–11 × 4–8) μm; it was found in nine (69%) hosts. Sporulated oocysts of Isospora aquatici n. sp. were subspheroidal, 20.9 × 18.4 (15–24 × 13–21) μm with sporocysts ellipsoidal, 11.8 × 9.0 (9–14 × 7–11) μm; it was found in two (15%) hosts.     

The mole as a surface dweller

Evidence is presented that, in normal circumstances, moles spend a part of their active periods on the soil surface. In abnormal circumstances, as during a drought in Northern France (in 1964) when the soil became too hard to dig, many moles were seen and captured alive on the surface of the soil.     

Skin lipids from Saudi Arabian birds

Skin lipids play an important role in the regulation of cutaneous water loss (CWL). Earlier studies have shown that Saudi desert birds exhibit a tendency of reduced CWL than birds from temperate environment due to adaptive changes in composition of their skin lipids. In this study, we used thin-layer chromatography (TLC) for separation and detection of non-polar and polar lipids from the skin of six bird species including sooty gull, brown booby, house sparrow, Arabian waxbill, sand partridge, and laughing dove. The lipids were separated and detected on Silica gel G coated TLC plates and quantified by using densitometric image analysis. Rf values of the non-polar lipids were as follows: cholesterol (0.29), free fatty acids (0.58), triacylglycerol (0.69), fatty acids methyl esters (0.84) and cholesterol ester (0.97). Rf values for the polar lipids were: cerebroside (0.42), ceramide (0.55) and cholesterol (0.73). The results showed the abundance of fatty acids methyl esters (47.75–60.46%) followed by triacylglycerol (12.69–24.14%). The remaining lipid compositions were as follows: cholesterol (4.09–13.18%), ceramide (2.18–13.27%), and cerebroside (2.53–12.81%). In conclusion, our findings showed that TLC is a simple and sensitive method for the separation and quantification of skin lipids. We also reported a new protocol for lipid extraction using the zirconia beads for efficient disruption of skin tissues. This study will help us better understand the role of skin lipids in adaptive physiology towards adverse climatic conditions.     

Lactoperoxidase-catalyzed iodination of surface membrane lipids

Lactoperoxidase-catalyzed iodination of intact cells, is known to label predominantly, if not exclusively, the exposed tyrosine residues of cell surface proteins. The present study demonstrates that during this iodination process surface membrane lipids are also iodinated through an enzyme-dependent step. Phosphatidylcholine, cholesterol-phosphatidylcholine liposomes and confluent secondary cultures of chick embryo cells were iodinated by the lactoperoxidase-glucose oxidase-glucose [¹²⁵I] procedure. Liposomes were efficiently labeled. In the cells, 20–30% of the radioactivity was found in proteins and 20–30% in the lipids. Both neutral and polar lipids were found to bind [¹²⁵I] covalently. Controls in which lactoperoxidase was omitted showed < 6% of the radioactivity found in liposomes or cells labeled with the enzyme.     

Thematic review series: skin lipids. Antimicrobial lipids at the skin surface

The skin surface represents our interface with the external environment, and as such, is our first line of defense against microbial colonization and infection. Lipids at the skin surface are thought to underlie at least part of an antimicrobial barrier. Some of these lipids are synthesized in the epidermis and are carried to the surface as cells differentiate, whereas others are secreted onto the surface from the sebaceous glands. One such group, free sphingoid bases, are known to have broad antimicrobial activity, and our previous studies demonstrate their presence at the skin surface. Free sphingoid bases may be generated by enzymatic hydrolysis of epidermal ceramides. In addition, our preliminary results demonstrate potent antibacterial activity associated with two specific fatty acids derived from sebaceous triglycerides. Most remarkably, one of these fatty acids (sapienic acid, C16:1Delta6), in combination with a low concentration of ethanol, is very effective against methicillin-resistant Staphylococcus aureus (MRSA). In fact, this combination was far more effective than mupirocin with or without ethanol. Mupirocin is a "gold standard" for activity against MRSA.     

The composition of the skin surface lipids of the gerbil

The skin surface lipids of the gerbil were found to consist sterol esters (10%), wax diesters (36.3%), triacylglycerol (26.1%), free fatty alcohols (8.8%), free fatty acids (5.4%), cholesterol (8.4%) and polar lipids (5%). The wax diesters, identified as Type II, were made up of saturated 1,2-diols with odd carbon number, esterified with two molecules of unsubstituted fatty acids with even carbon number. Both the triacylglycerols and the free fatty acid fractions had saturated and unsaturated components. The free and esterified sterols were all cholesterol. The sterol esters contained saturated monoenoic and dienoic fatty acids, with both straight- and branched-chain components. The fatty alcohols were all straight-chain in structure, mostly of even carbon number. Comparison of these results with those previously reported for other species, indicates that the gerbil skin surface lipids are unique in that they contain diacyl alkane diols and fatty alcohols, both of which consist exclusively of saturated components.     

Fish skin surface lipids: phospholipids

Phospholipid components of skin surface secretions of four Indian freshwater fishes were analysed using different solvent systems in one-dimensional and two-dimensional thin-layer chromatography, and quantified using a spectrophotometer. The phospholipid pattern of the skin secretions is similar to that of membrane lipids. Phosphatidyl choline and phosphatidyl ethanolamine are the major components constituting approximately two-thirds of the total phospholipids. Sphingomyelin and phosphatidyl serine are present in relatively low quantities. Phosphatidic acid, phosphatidyl glycerol, lysophosphatidyl choline and lysophosphatidyl ethanolamine, which may be important metabolic intermediates, are present in very low quantities in the skin surface secretions of all four species. It is suggested that the lipids are derived from membranous profiles in the secretions of skin glands, extrusion of membrane-bound vesicles from surface epithelial cells, and exfoliated cells. The results are discussed in relation to the biochemical and biological significance of these lipids in the skin secretions.     

Skin stem cells: rising to the surface

The skin epidermis and its appendages provide a protective barrier that is impermeable to harmful microbes and also prevents dehydration. To perform their functions while being confronted with the physicochemical traumas of the environment, these tissues undergo continual rejuvenation through homeostasis, and, in addition, they must be primed to undergo wound repair in response to injury. The skin's elixir for maintaining tissue homeostasis, regenerating hair, and repairing the epidermis after injury is its stem cells, which reside in the adult hair follicle, sebaceous gland, and epidermis. Stem cells have the remarkable capacity to both self-perpetuate and also give rise to the differentiating cells that constitute one or more tissues. In recent years, scientists have begun to uncover the properties of skin stem cells and unravel the mysteries underlying their remarkable capacity to perform these feats. In this paper, I outline the basic lineages of the skin epithelia and review some of the major findings about mammalian skin epithelial stem cells that have emerged in the past five years.     

Gas-Vacuolated Strains of Microcyclus aquaticus

Two strains of gas-vacuolated heterotrophic bacteria have been isolated from freshwaters by using 0.01% peptone enrichments. Both are nonmotile, vibrioid organisms that form rings before division. In terms of these morphological traits and other characteristics, including nutritional characters and deoxyribonucleic acid base composition, these new isolates are very similar to Microcyclus aquaticus. It is proposed that they be considered strains of this species.