To our knowledge, this study provides the first electrophysiological data on the collecting duct system of an anuran amphibian. We examined the characteristics of K+ transport by the collecting duct system of the toad Bufo bufo. Qualitatively, there seemed to be no difference between K+ transport in cells from collecting tubules and from collecting ducts. Our data indicate that luminal K+ channels would provide a pathway for secretion of K+ from the cell into the lumen.. The collecting duct system of amphibians is a heterocellular epithelium composed of principal and intercalated cells (Møbjerg et al., 1998). In this context it should be noted that the Vbl of collecting duct cells fell into two groups, one being more hyperpolarized than the other. We do not know if this distribution (Fig. 2A) reflects two populations of cells in different functional states, or cells with different transport characteristics, e.g. principal and intercalated cells. In the present study it was not possible to ...
The Common toad Bufo bufo sensu lato is a widespread, morphologically conserved taxon. Recent studies have uncovered deep genetic differentiation between population groups, highlighting the need to revise the current taxonomy of the group and recognize additional species. Here we investigate patterns of variation in molecular (a mitochondrial DNA restriction enzyme assay and sequence data for two nuclear DNA fragments totalling 979 bp) and 17 morphological variables in Northern France where two of these groups meet (B. bufo sensu stricto and B. spinosus), in order to delineate their contact zone and uncover characters that would allow discrimination of the two taxa. Mitochondrial DNA data show an abrupt transition from areas where B. bufo is present to those inhabited by B. spinosus, with a narrow area of overlap east of the city of Caen. Morphometric characters, particularly those related to the positioning of the parotoid glands and metatarsal tubercle shape and size, proved useful in ...
A randomized, replicated, controlled study in 2007 in a laboratory in Virginia, USA (Woodhams et al. 2012) found that survival of mountain yellow-legged frogs Rana muscosa naturally infected with chytridiomycosis was not increased by adding chytrid-inhibiting skin bacteria. Survival of frogs treated with bacteria was 50% compared to 39% for infected controls. Infection was not cleared in surviving frogs. However, weight loss was reduced with treatment (0.1 vs 0.4 g/week). Wild-caught frogs were randomly assigned to treatments. Twenty were bathed in water containing bacteria (Pedobacter cryoconitis) isolated from mountain yellow-legged frog and 13 control frogs in water alone for two hours. Frogs were swabbed and tested at seven and 13 days after treatment.. A randomized, replicated, controlled study in 2010 in a laboratory in Switzerland (Woodhams, Geiger, Reinert, Rollins-Smith, Lam, Harris, Briggs, Vredenburg & Voyles 2012) found that survival of common toad Bufo bufo toadlets was not ...
To understand the neural mechanisms underlying the toads behavioral responses, Ewert performed a series of recording and stimulation experiments. First and foremost, the results allowed him to understand the way the visual system is constructed and connected to the central nervous system. Secondly, he discovered areas of the brain that were responsible for differential analysis of stimuli. First, the retina is connected to the optic tectum by at least three types of ganglion cells, each with an excitatory receptive field and a surrounding inhibitory receptive field, but they differ in the diameter of their central excitatory receptive fields. Diameters in Class II (R2) ganglion cells are approximately four degrees visual angle. Those in Class III (R3) cells are about eight degrees and Class IV (R4) ganglion cells range from twelve to fifteen degrees. As stimuli move across the toads visual field, information is sent to the optic tectum in the toads midbrain. The optic tectum exists as an ...
1. The upper thermal death-point of the slow worm (Anguis fragilis) is significantly above that of either the toad (Bufo bufo) or the frog (Rana temporaria). That of the toad differs only slightly from that of the frog.. 2. In response to external variation with respect to temperature and humidity, the body temperature of the toad behaves in a manner similar to that of the frog, being considerably below that of the air at low humidities, though appreciably above that of the wet-bulb thermometer. It is concluded that the toad loses water as freely as the frog.. 3. The body temperature of the slow worm and that of the alligator (A. mississippiensis) differs only slightly from that of the air under all conditions of sustained air temperature and humidity.. 4. The body temperature reaction of the alligator is more sluggish than that of the slow worm, presumably owing to the higher thermal capacity of the animal.. 5. The significance of these results in relation to the evolution of the terrestrial ...
The optical sectioning video imaging technique was used for measurements of the volume of mitochondria-rich (m.r.) cells of the isolated epithelium of toad skin. Under short-circuit conditions, cell...
The epitope H contains an O-linked N-acetylglucosamine (O-GlcNAc) residue in a specific conformation and/or environment recognized by monoclonal antibody H (mAbH). We have previously shown that the epitope H is present in more than one polypeptide and in various types of normal and pathological cells. In the present study, we focused on mitochondria-rich normal, metaplastic, and neoplastic cells, prompted by our recent immuno-electron microscopy findings that mAbH clearly stains the mitochondria of breast epithelial cells in infiltrating ductal breast carcinomas and fibroadenomas. The indirect immunoperoxidase method was applied using the mAbH to investigate the distribution of the epitope H in mitochondria-rich normal cells and in metaplastic and neoplastic oncocytic cells. Immunohistochemical staining for the mAbH was observed in oxyphil cells of parathyroid glands, in striated duct cells of parotid glands, in urinary tubules of kidneys, in parietal cells of gastric body mucosa, in oxyphil ...
My assumption was this was why toads tended to breed in larger ponds with fish - their toxins keep them relatively safe from fish predation, but the fish keep down numbers of other tadpole predators such as newts and invertebrates. This would also explain the shoaling behaviour - having tried one and found it unpalatable, a fish would be likely to leave the rest of the shoal alone. Having said that Ive never actually seen any data on how much different fish species do prey on / avoid toad tadpoles, so Id be interested if anyone knows of any research on the subject ...
The Common Toad...only smaller Shot Handheld with Canon 50mm 1.4 with stacked Macro filters on Canon TLb [IMG] [IMG] My GF found this little guy in...
Complex epithelia have multiple functions, including the regulation of ion transport and homeostasis. A failure to regulate ionic homeostasis is a hallmark of many human diseases. For example, defects in the function of epithelia whose primary function is ion transport, such as those found in kidney and epididymis, lead to abnormalities such as distal renal acidosis and male sterility. In addition, although ion transport is not the primary function of other epithelia, such as the secretory and mucociliary epithelia found in the gut and lung, ionic regulation is crucial for their normal function. In diseases such as cystic fibrosis, failure of ionic regulation is associated with abnormalities in mucus consistency and secretion, which has deleterious effects in the gut and lungs.. Most epithelia consist of several cell types, including specialised cells dedicated to ionic regulation (known as ionocytes, mitochondria-rich cells, proton-secreting cells or intercalated cells). Challenges in ...
Listed as Least Concern since, although its Extent of Occurrence is less than 20,000 km2, it occurs in an area of extensive, suitable habitat which appears not to be under significant threat, it has a presumed large population, and it is unlikely to be declining fast enough to qualify for listing in a more threatened category ...
Bufotoxins are a family of toxic steroid lactones. They occur in the parotoid glands, skin and poison of many toads (genus Bufo) and other amphibians, and in some plants and mushrooms. The exact composition varies greatly with the specific source of the toxin. It can contain: 5-MeO-DMT, bufagins, bufalin, bufotalin, bufotenin, bufothionine, epinephrine, norepinephrine, and serotonin. The term bufotoxin can also be used specifically to describe the conjugate of a bufagin with suberylargine. The toxic substances found in toads can be divided by chemical structure in two groups: bufadienolides which are cardiac glycosides (e.g. bufotalin, bufogenin) tryptamine related substances (e.g. bufotenin) Toads known to secrete bufotoxin are:[citation needed] Bufo alvarius Bufo americanus Bufo arenarum Bufo asper Bufo blombergi Bufo boreas Bufo bufo Bufo bufo gargarizans Bufo Gutturalis Bufo formosus Bufo fowleri Rhinella marina (formerly Bufo marinus) Bufo melanostictus Bufo peltocephalus Bufo quercicus ...
New analytical methods are improving our ability to reconstruct robust species trees from multilocus datasets, despite difficulties in phylogenetic reconstruction associated with recent, rapid divergence, incomplete lineage sorting and/or introgression. In this study, we applied these methods to res …
Define genus Bufo. genus Bufo synonyms, genus Bufo pronunciation, genus Bufo translation, English dictionary definition of genus Bufo. Noun 1. genus Bufo - type genus of the Bufonidae; common toads of New and Old Worlds amphibian genus - any genus of amphibians Bufonidae, family Bufonidae -...
Listed as Least Concern in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category ...
In the last few years our interest has been devoted to the energy metabolism of the eggs of the common toad Bufo arenarum Hensel which, like some other amphibian eggs, can cleave at a normal rate in the absence of oxygen or in the presence of cyanide (Barbieri & Legname, 1957). Under anaerobic conditions a rapid accumulation of lactic acid gives evidence of an intense glycolytic activity, which is inhibited when the eggs are returned to oxygen (Pasteur effect) (Barbieri & Salomón, 1963). Furthermore, an increase in oxygen uptake during the first 2 h of recovery has been observed (payment of the oxygen debt) (Legname, 1966). Taking into account the low value of the respiratory quotient (r.q. = 0·5-0·7) during this period it can be assumed that most of the oxygen is not involved in the oxidation of lactate (Legname, 1966).. ...
The collecting duct of the mammalian kidney is involved in urine acidification. Recent studies in the turtle bladder suggest that hydrogen ion secretion in response to elevated CO2 is regulated by insertion of hydrogen pumps into the luminal membrane of the mitochondria-rich cells. Because intercalated cells of the collecting duct are structurally similar to mitochondria-rich cells of the amphibian bladder, we studied the rat outer medullary collecting duct (OMCD) during respiratory acidosis to determine whether changes compatible with hydrogen ion secretion occur in the intercalated cells. Rats were studied during normal acid-base conditions and after 4-5 h of respiratory acidosis. After collection of physiologic data, the kidneys were fixed by in vivo perfusion and processed for electron microscopy. No changes were observed in the principal cells of the OMCD. Morphometric analysis revealed a significant increase in the surface density of the apical plasma membrane and a decrease in the number ...
Toads. Reptilia.. Toads belong to the most poisonous reptiles.. In olden times, being looked upon as horrible things, they were given in horrible diseases. During the rage of improvement the remedy was thrown overboard, and even the poisonous qualities doubted, until rare experiments, especially those by Vulpian, have settled the question. In 1832 Henke, our great prover, was the first in our school to call attention to it ; his observations were published in Meyers Monatsblatt, 1860 ; in 1834 the Hom opathic Society of Th ringen sent some symptoms to the Archives of Stapf (vol. xiv, No. 2, page 102). In 1849 Mure published a proving with his preparation, taken from the most common toad in Brazil, called by him Bufo satyhiensis. This was translated by Hempel and Allen. Houat published one of his provings in Nouvelles Donn es. This was translated three times --by Lippe, Lilienthal and Allen. In 1859, Destrone, in a French journal, collected notes from all old writers and also made some provings. ...
Amphibian Bufo Daylight Frog: 20 assigned downloads, like Natterjack Toads (Bufo calamita), pair before spawning from stock-photos
El gènere Bufo és molt cosmopolita, ja que sel pot trobar a tot el planeta sota condicions molt adverses. No obstant això, és absent de les regions polars, dAustràlia -llevat de Bufo marinus, del qual se sospita que hi va ser introduït-, de Nova Guinea i illes adjacents. ...
The variability of microsatellites BM224 and Bcal7 was studied for the first time in three species of the diploid-polyploid complex of Bufo viridis (B. viridis, B. oblongus, and B. pewzowi). The locus
Dubois, A. & R. Bour. 2010: The nomenclatural status of the nomina of amphibians and reptiles created by Garsault (1764), with a parsimonious solution to an old nomenclatural problem regarding the genus Bufo (Amphibia, Anura), comments on the taxonomy of this genus, and comments on some nomina created by Laurenti (1768). Zootaxa, 2447: 1-52 ...
Common Frog is not common and Common Toads are occasionally seen but the commonest amphibian by far is the large and very noisy Marsh Frog. The first individuals of this species were originally introduced into Britain into a small garden pool at Stone-in-Oxney in the winter of 1934-35. Since then the population has increased and spread dramatically and they can now be seen or heard in many ditches and pools throughout Romney Marsh. ...
Bufotenin: A hallucinogenic serotonin analog found in frog or toad skins, mushrooms, higher plants, and mammals, especially in the brains, plasma, and urine of schizophrenics. Bufotenin has been used as a tool in CNS studies and misused as a psychedelic.
There was one thing different about the toad pools this spring that may have contributed to the toad visitations. Both pools were surrounded by a mass of Spring Peepers creating a loud chorus. Im wondering if the Peeper song alerted the toads to the fact that a suitable breeding pool was available. The newly hatched Peeper tadpoles shown above are just two of dozens hanging in the algae around the edge of the pools. This toad pool venture may just turn out to be a success ...
Biker Babe Toad - Green We were so excited to get this amazing new Biker Babe Toad - Green on the site, we havent even had the chance to write a whimsical description!We have loved these toads for the past few years and ...
Population genetics of the amphibian pathogen Batrachochytrium dendrobatidis (Bd) show that isolates are highly related and globally homogenous, data that are consistent with the recent epidemic spread of a previously endemic organism. Highly related isolates are predicted to be functionally similar due to low levels of heritable genetic diversity. To test this hypothesis, we took a global panel of Bd isolates and measured (i) the genetic relatedness among isolates, (ii) proteomic profiles of isolates, (iii) the susceptibility of isolates to the antifungal drug caspofungin, (iv) the variation among isolates in growth and phenotypic characteristics, and (v) the virulence of isolates against the European common toad Bufo bufo. Our results show (i) genotypic differentiation among isolates, (ii) proteomic differentiation among isolates, (iii) no significant differences in susceptibility to caspofungin, (iv) differentiation in growth and phenotypic/morphological characters, and (v) differential ...
The effect of past climatic changes on the distribution of organisms is a fertile field of research that has been tackled in many different ways. Because the fossil record provides direct access to the chronological and geographic dimensions of biological events occurred in the past, it can be a useful tool for assessing range contractions and expansions related to climatic changes. Here, we provide support for the recent shrinkage of the range of a frigophilous anuran, the common frog, Rana temporaria Linnaeus, 1758, by analyzing the amphibian fossil assemblage coming from the Grotta di Equi, a Late Pleistocene site (about 45 ka) located in the Apuan Alps (northern Apennine chain, Massa-Carrara Province, Italy). Besides, R. temporaria, the assemblage includes cf. Salamandra salamandra Linnaeus, 1758 and Bufo bufo Linnaeus, 1758. The presence of R. temporaria in the Apuan Alps during a cold interglacial phase at an elevation that is much lower than the minimum current elevation in the region (about
In the Bufo spinulosus group of Martin, 1972, in Blair (ed.), Evol. Genus Bufo: 57. Considered a distinct species by Cei, 1972, in Blair (ed.), Evol. Genus Bufo: 82-92; still treated as a subspecies of Bufo spinulosus by Gorham, 1974, Checklist World Amph.: 84. Cei, 1962, Batr. Chile: 42-44, provided an account (as Bufo spinulosus atacemensis). Sallaberry-Ayerza and Méndez-Torres, 2002, Herpetol. Rev., 33: 218-219, commented on the range and provided a range extension. Sallaberry-Ayerza, Soto-M., Correa-Quezada, and Méndez-Torres, 2007, Herpetol. Rev., 38: 214, provided range extensions and discussed the range. Correa-Quezada, Sallaberry-Ayerza, Jara-Arancio, Lobos, Soto-M., and Méndez-Torres, 2008, Check List, 4: 478-484, detailed the range in and discussed all known records as well as providing evidence of allopatry of this species and Rhinella arunco. Veloso, Sallaberry-Ayerza, Correa-Quezada, and Méndez, 2012, J. Herpetol., 46: 568-577, found an area of contact in the Estero Pupío area ...
Poynton, Loader, Conradie, Rödel, and Liedtke, 2016, Zootaxa, 4098: 73-93, removed Sclerophrys pusilla from the synonymy of Sclerophrys maculata and redescribed the holotype of this species. See comments under Sclerophrys maculata for relevant literature. Angola records in Poynton and Haacke, 1993, Ann. Transvaal Mus., 36: 1-16 (as Bufo maculata). Poynton and Broadley, 1988, Ann. Natal Mus., 29: 460-463, discussed the uncertainty of the synonymy of Bufo pusillus with Bufo maculatus, citing immunological evidence of Maxson, 1981, Herpetologica, 37: 96-104. See also Lambiris, 1988, Lammergeyer, 39: 51, who recognized Bufo pusillus, and Channing, 1989, Lammergeyer, 40: 1, who disputed Lambiris conclusion. Rödel, 2000, Herpetofauna W. Afr., 1: 47-53, Channing, 2001, Amph. Cent. S. Afr.: 84, Lötters, Wagner, Bwong, Schick, Malonza, Muchai, Wasonga, and Veith, 2007, Fieldguide Amph. Rept. Kakamega Forest: 14-15, and Du Preez and Carruthers, 2009, Compl. Guide Frogs S. Afr.: 146-147, provided ...
Japans largest platform for academic e-journals: J-STAGE is a full text database for reviewed academic papers published by Japanese societies
There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca2+-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from the fast-relaxing phase was investigated for kinetic analysis of the isometric rela...
dinner, after : Aloe., anac., canth., cast., cycl., ferr., gamb., mag-c., mag-m., nat-c., nat-m., plb., psor., thuj., zinc.. dread of liquids, with : Agn., am-c., arn., bell., cann-i., canth., caust., cocc., hell., hyos., lac-c., lach., lyc., lyss., merc., nat-m., nux-v., rhus-t., samb., sel., stram., tarent.. eating, while : Ail., aloe., am-c., bufo., coc-c., cocc., lach., nat-c., psor.. after : Aloe., anac., bell., bry., calad., caust., coc-c., cocc., cycl., elaps., graph., guare., lyc., nat-c., nit-ac., phel., phos., sil.. extreme : Acet-ac., Acon., aesc., aeth., agar., all-c., all-s., alum., am-m., anac., anan., ant-c., ant-t., apis., Arg-n., arn., ars-h., ars-i., Ars., asar., aspar., aur-m., aur., bar-c., bar-i., bar-m., bell., bism., bor., bov., Bry., bufo., cadm., calad., Calc-s., Calc., camph., cann-s., canth., caps., carb-ac., carb-an., carb-s., carb-v., Caust., cedr., Cham., chel., Chin., chlor., cic., cina., coc-c., cocc., coff., colch., coloc., con., cop., croc., crot-c., crot-h., ...
O sapo do gênero Bufo possui nas suas glândulas paratóides uma secreção mucóide contendo toxinas como bufaginas e bufotoxinas, que são esteróides cardiogênicos. Os cães podem atacar os sapos, entrando em contato com o veneno por meio das mucosas. Um canino, da raça Bulldog Francês, foi encaminhado ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (UFRGS) para a necropsia com histórico de provável intoxicação por veneno de sapo. Na necropsia o canino apresentava pulmões aumentados de volume, avermelhados e com edema, e rins de coloração vermelho-escura. As alterações microscópicas indicaram congestão, hemorragia e edema pulmonar. Nos rins, no baço e nos linfonodos foi observada congestão. As análises toxicológicas para os venenos de rotina foram negativas. Porém, a investigação do veneno de sapo a partir de cromatografia por camada delgada e gasosa demonstrou resultado positivo, revelando ser esta a causa da morte do canino ...
Dubruille R, Murad A, Rosbash M, Emery P. A constant light-genetic screen identifies KISMET as a regulator of circadian photoresponses. PLoS Genet. 2009 Dec; 5(12):e1000787 ...
Live toads at Tesco? Like other Western firms, the store giant is having to adapt to local customs to cash in on Chinas economic boom
Does desiccation risk drive the distribution of juvenile cane toads (Bufo marinus) in tropical Australia? - Volume 25 Issue 2 - Travis Child, Benjamin L. Phillips, Richard Shine
In the late 1960s, LSD evangelist Art Kleps founded a psychedelic church called the Neo-American Church. The churchs newsletter was called "Divine Toad Sweat".[3] In 1984, Bufo toad evangelist Albert Most revealed his Church of the Toad of Light with his publication of the book Bufo Alvarius: Psychedelic Toad of the Sonoran Desert. The Sonoran Desert is in New Mexico. This small booklet details how to use the Bufo toad for ritual and pleasure, as well as how to catch the Bufo alvarius toad, extract or "milk" the glandular secretions, dry them, and "enjoy the smoked venom." Mosts book claims that 5-MeO-DMT (5-methoxy-N, N-dimethyltryptamine) is the active hallucinogen, not bufotenine. He is correct, as 5-MeO-DMT is the O-methylated version of bufotenine.[4] Again, it is important to mention that 5-MeO-DMT is present in only one of the more than 200 types of Bufo toads ...
Light grey or tan skin with bumps, or warts all over. One large wart behind each eye, which is often brown. Puncturing and ingesting the liquid from these large warts will not kill a human or animal, but it will make them quite sick. Unlike the marine toad in Australia, whose warts have killed many domestic dogs and cats ...
Following freeze-fracture of the rat epididymis, a population of cells whose apical, but not baso-lateral, plasma membrane contains elongated intramembrane particles was found in the initial segment. From their size, shape and distribution, these cells are assumed to be the so-called apical cells of this segment. Apical cells also contain the enzyme, carbonic anhydrase which, together with the presence of rod-shaped particle on their membranes, permits their classification as mitochondria-rich cells, a specialized cell type found in some transporting epithelia. On the basis of these observations, we suggest that the apical cells may play a role in fluid and/or electrolyte transport in the initial segment of the epididymis. ...
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It was the clear cellophane bags of toads that made us linger. As I stared at the toads, one of them suddenly moved. Holy moly. All the toads were alive.
A toad is an amphibian of the order Anura, a classification which also includes the frog. I always thought the difference between toads and frogs revolv...
... : Pulmonary respiration is breathing through the lungs, as human do. Lungs are the main respiratory organs of toad. The
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... : Amiloride inhibition of basolateral membrane depolarization in response to increased bath osmolality correlates with afferent neural activity and behavior ...
Have you ever heard of the Cane Toad? If you havent, youre probably not from Australia. Hawaii was the source population for this introduction, otherwise known as the Marine Toad (Bufo marinus). After its introduction to the land-down-under, it has reached plague proportions. Its not as bad in Hawaii, yet, youd be challenged not to find one of these toads on any night in the back of a Hawaiian valley. The toads are unique in that they have toxic secretions that will ooze from glands on their neck if they feel threatened. Dogs can easily die after biting a marine toad. These same secretions, when scrapped from a frog, can be smoked or licked to receive a hallucination. This is not recommended however, as Hazen Audel has tried this, and subsequently come down with a tongue fungus that was not pretty.. ...
by T. Kawauchi. Introduction. Toad is a generic name of four kind of frogs. The four kinds are "Asiatic toad", "Japanese toad", " Japanese stream toad ", and "Marine toad. " The marine toad is a foreign toad. A toad is any of a number of species of amphibians in the order Anura characterized by dry, leathery skin (usually brownish-colored), short legs, and wart-like parotoid glands. Description & Taxonomy. The scientific name of Japanese toads is Bufo japonicas Temminck & Schlegel, 1838. Size is about 7-15cm. The color is usually a reddish brown. There are four aliases. The alias is"Hiki","Gamagaeru","Gama","Ibogaeru" and "Senjo". Limbs are comparatively short, and the enlarged body moves slowly. The Japanese toads web doesnt develop so much. Other frogs can jump more though than Japanese toad is a little. The mucus of white poisonous like milk is secreted from a lot of Ivo who puts out a strong venom from a big parotoid that exists in back of the head, and exists in the skin, especially the ...
Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Has antibacterial activity against the Gram-positive bacterium S.aureus and against the Gram-negative bacterium E.coli with a MIC of 1 uM and 8 uM respectively. No antifungal activity against C.albicans.
1. Fragments of skin taken from the back of the leopard frog were cultivated in a mixture of plasma and muscle extract of the same species.. 2. A few hours after explanation, processes of activity are seen to arise, which finally lead to the formation of a compact epithelial rim around the fragment of skin.. 3. These epithelial cells undergo gradual transformation into a spindle-shaped type of cell; in this form they resemble the spindle cells which have been described as connective tissue cells.. 4. The growth of a rim of tissue around the explanted fragments of skin may be ascribed principally to the activity of a basal layer of epithelial cells, the units of which first advance into the medium as compact membranes by means of the so called epithelial movement, but which later become separated from the compact membrane, and having assume a spindle form, spread according to the manner of connective tissue cells.. 5. In contradistinction to this basal layer, the cells of an upper and middle ...