Hair density in the Eurasian otter <Emphasis Type="Italic">Lutra lutra</Emphasis> and the Sea otter <Emphasis Type="Italic">Enhydra lutris</Emphasis>

The hair density of adult Eurasian otters Lutra lutra (Linnaeus, 1758) and sea otters Enhydra lutris (Linnaeus, 1758) was analysed using skin samples taken from frozen carcasses. Lutra lutra exhibited a mean hair density of about 70 000 hairs/cm² (whole body, appendages excepted), the mean individual density ranging from about 60 000 to 80 000 hairs/cm². The dominant hair type were secondary hairs (wool hairs), the hair coat comprising only 1.26% of primary hairs (PH). Secondary hair (SH) density remained constant over the body (appendages excepted), whereas a few variations in PH density were observed. Neither an influence of the sex, nor a seasonal variation of the hair coat was found, moulting seems to be continuous. Enhydra lutris had a hair density between 120 000 and 140 000 hairs/cm², the primary hairs representing less than 1% within the hair coat. Hair density remained quite constant over the regions of the trunk but was lower at the head (about 60 000 hairs/cm² on the cheek). The hair follicles were arranged in specific groups with different bundles of varying size, normally comprising dominant numbers of wool hair (SH) follicles. Invariably there was always a large central primary hair follicle and numerous sebaceous glands between the bundles and principally around the PH follicles. The results are discussed related to possible ecological influences on hair coat density.     

Dermatophytes and other keratinophilic fungi causing ringworm of horses

From 60 horses showing skin lesions, 42% were positive for fungal infection. Horses less than 2-year old were more susceptible to this infection. Fourteen species belonging to nine genera of kerationphilic and cycloheximide-resistant fungi were recovered from collected specimens.Trichophyton was the dominant genus of whichT. equinum was the most common. This species proved to be the main causative agent of ringworm in horses. In addition to dermatophytes, many species of the isolated fungi were keratinophilic. The presence of such fungi on hairs and skin of horses may create an opportunity for them under special circumstances to become invasive to the skin or hair and thus cause primary or secondary infection of the animals.     

Early cytological events in the infection of the root hairs ofTrifolium repens byRhizobium leguminosarum biovartrifolii observed by glass slide culture in living seedlings

This report describes the early cytological events in the infection byRhizobium leguminosarum biovartrifolii of the root hairs ofTrifolium repens seedlings kept alive on agar medium in glass slide culture experiment. The infection threads bearing rhizobia were formed as soon as the epidermal cells began to emerge as root hairs. On the top of some of these infected emerging root hairs, there were smoky, cell-debris-like bodies, which appeared to be derived from the cell wall dug by rhizobia. Similar bodies were also observed in longer root hairs. None of the root hair cells along the length of the roots which contained infection threads were curled or distorted. A substantial number of pink-colored nodules were later formed on the roots with non-curled infected root hairs.     

TRICHOPHYTON TONSURANS (CRATERIFORME) INFECTION OF THE SCALP

Of 484 cases of ringworm of the scalp observed in a period of two and a half years at a clinic in Los Angeles, 57 (11.78 per cent) were caused by Trichophyton tonsurans, an organism previously considered an infrequent cause of tinea capitis in the United States. The hairs at the site of infection with this organism are distinctively fluorescent when viewed under a Wood light—glowing white rather than green as do hairs infected with microsporum. Endothrix spore formation may be noted in microscopic examination of infected hairs. Material planted on Sabouraud''s media grows as a typical crateriform colony. Occasionally variant growths on cultures are obtained.Trichophyton tonsurans may cause either dry, scaly lesions or inflammatory reaction. In the present series the incidence of cure was higher and the period of treatment shorter for patients with the inflammatory variety. Various antifungal preparations were employed for topical application and although the results were extremely variable, it was felt that some benefit was derived from their use. For lesions of the dry, non-inflammatory type, roentgen ray epilation appeared to be the treatment of choice.     

A new method for DNA extraction from feces and hair shafts of the South China tiger (Panthera tigris amoyensis)

It is commonly known that tigers (Panthera tigris) groom themselves by licking their coats, which leads to an abundance of hairs in their feces. These hairs are designated specially as “fecal hairs”. In our study, in order to explore fecal hairs potential as a DNA source for genetic analysis, 55 fecal hair samples were collected from 23 captive South China tigers (P. t. amoyensis). According to the amplification of mitochondrial primers loop F and loop R, DNA quality of noninvasive samples were grouped into three grades: grade I—the highest-quality DNA, grade II—high-quality DNA, and grade III—poor-quality DNA. No failed amplifications on microsatellite primers and only 0.27% genotyping errors occurred with grade I fecal hair DNA, as compared with 9.4% failed amplifications on microsatellite primers and 9.5% genotyping errors with grade II fecal hair DNA. It was found that 25.45% of fecal hair DNA was grade I and 65.45 and 10.00% of fecal hair DNA were grades II and III, respectively, as compared with 4.35% grade I fecal DNA and 34.78 and 60.87% grades II and III fecal DNA, respectively. Thus, higher-quality DNA can be extracted from fecal hairs than feces. In addition, DNA could be extracted from hair shafts of tigers and a minimum of 2000 hair shafts were required for visible DNA bands on a 1% agarose gel. These findings demonstrate that fecal hairs may serve as a convenient and reliable genomic DNA source for genotype analysis. Zoo Biol 28:49–58, 2009. © 2008 Wiley-Liss, Inc.     

Hair morphology and systematics ofPhysalis (Solanaceae)

Hair morphology was exammed on developing seedlings and mature plants of ten species from five of seven series inPhysalis. The taxonomic importance of hair development and the distribution of hair types then was evaluated with respect to other comparative data. Two classes of hair types were observed, as found in earlier investigations ofSolanum andRhododendron. The first hair class comprises a sequence from unbranched hairs to dendroid-stelliform hairs. Hairs of this class show considerable variability among taxa in size, presence or absence of glandular tips, and presence and degree of branching, and so were useful in making taxonomic comparisons. The second hair class consists of short hairs, each tipped with a multicellular gland. This second hair class was not useful taxonomically because of its lack of variability in morphology and its often rare occurrence on a plant. The taxa studied exhibit distinctive trichome features which serve to distinguish series and, in some cases together with other data, provided new insight into previously enigmatic species relationships.     

Evidence of hair loss after subacute exposure to 2-chloroethyl ethyl sulfide, a mustard analog, and beneficial effects of N-acetyl cysteine

Mustard gas has been used as a vesicant chemical warfare agent. However, a suitable biomarker for monitoring mustard gas exposure is not known. We observed that the hairs of the guinea pigs exposed intratracheally to subacute doses of 2-chloroethyl ethyl sulfide (CEES), a mustard analog, came out very easily though there was no sign of skin lesions or skin damage. Also the hairs looked rough and dry and lost the shiny glaze. There was no recovery from this hair loss, though the animals never became hairless, following CEES exposure. Hairs were observed in this study both visually and with light microscopy. Treatment with N-acetylcysteine (NAC) prior to CEES exposure could prevent the hair loss completely. Hence, sudden hair loss might be a good biomarker for subacute exposure of mustard gas to subjects at risks when the victims might have no other visible symptom of toxicity.     

The failure behavior of the anchorage of hairs during slow extraction

Treatment of excessive hair growth is an important issue in both dermatological and cosmetic practice. In contrast to treatments with medication, most physical methods are treatments that focus on the hair follicle. To obtain insight in the failure behavior of the anchorage of hairs, hairs were extracted (in vitro) from pig skin at a speed of 0.1mm/s, one at a time. The pulling force and tweezers displacement were recorded. The extracted hairs were classified with respect to the phase in the growing cycle: anagen (growing phase), telogen (resting phase) or other (catagen phase or unable to determine). The anagen hairs showed a different relation between the tweezers displacement and the pulling force than the telogen hairs. Moreover, the maximum force that could be applied before a hair was extracted proved to be lower for anagen hairs than for telogen hairs (0.36N, 1.8N, respectively). The extracted hair length, defined as the part of the hair that had been embedded in the skin which was extracted, was higher for anagen hairs than for telogen hairs (4.8mm, 3.0mm, respectively). Removing proximal skin tissue and the embedded parts of the anagen hair (root) resulted in a change of the extraction curves. The results indicate that two phenomena play a role in the anchorage of anagen hairs. We have proposed a model for the extraction of an anagen hair that has been based on these results: first the interface between hair and skin that is located around the inner root sheath (IRS) starts to fail, followed by failing of the hair itself in the region where the hair keratinizes.     

Trichophyton tonsurans infection of the scalp

Of 484 cases of ringworm of the scalp observed in a period of two and a half years at a clinic in Los Angeles, 57 (11.78 per cent) were caused by Trichophyton tonsurans, an organism previously considered an infrequent cause of tinea capitis in the United States. The hairs at the site of infection with this organism are distinctively fluorescent when viewed under a Wood light-glowing white rather than green as do hairs infected with microsporum. Endothrix spore formation may be noted in microscopic examination of infected hairs. Material planted on Sabouraud's media grows as a typical crateriform colony. Occasionally variant growths on cultures are obtained. Trichophyton tonsurans may cause either dry, scaly lesions or inflammatory reaction. In the present series the incidence of cure was higher and the period of treatment shorter for patients with the inflammatory variety. Various antifungal preparations were employed for topical application and although the results were extremely variable, it was felt that some benefit was derived from their use. For lesions of the dry, non-inflammatory type, roentgen ray epilation appeared to be the treatment of choice.     

The effect of aluminium concentration on root hairs in white clover (Trifolium repens L.)

The effect of aluminium (Al) on root hair length and number is quantified using solution culture techniques with genotypes from white clover cultivar Tamar, that had previously been selected for long and short root hairs. The population differences were maintained in control (0 Al) treatments, with the long-haired population having hairs three times longer than the short-haired population. At an activity of 2.2 µM Al³⁺, root hair length decreased in both populations, the magnitude of the decrease being greater for the long-haired population. Root hair numbers decreased in a similar manner for both populations. At an activity of 4.4 µM Al³⁺ or higher, root hairs virtually disappeared and root growth was very stunted. The effect of Al on root hair development has not been previously quantified, however other workers have observed reduced root hair development in other species at activities of Al greater than 2.5 µM Al³⁺.     

Calcium localization pattern in clover root hair cells associated with infection process: Studies with aureomycin

Summary Localized regions of calcium were shown to change in clover root hair cells after infection withRhizobium trifolii as shown with the Ca⁺⁺ binding antibiotic, chlorotetracycline. Some root hairs from the immature zone showed increased calcium fluorescence distributed through most of the cell. These root hair had a morphology with a notched side wall, typical of cells infected by bacteria. The maturing root hairs that show a growing infection thread or start of an infection thread, have a similar increased calcium fluorescence, especially around the area of origin of infection thread and tip of the root hair cell.Kettering contribution no. 722.     

Root hair deformation in the white clover/Rhizobium trifolii symbiosis

Rhizobium trifolii most frequently infects its host white clover (Trifolium repens L.) by means of infection threads formed in markedly curled root hairs. Rhizobium infections are classified as either lateral or apical based on whether they originate in the branches or at the apex of the root hairs. A quantitative estimate of lateral and apical infection in the region of the host root (Trifolium repens L. cv. Regal Ladino) that possessed mature and immature root hairs at the time of inoculation with Rhizobium trifolii TAI (CSIRO, Canberra City, Australia) indicated that lateral infection occurred more frequently in the mature root hair region of the root. Apical infections were more common in the immature root hair region. Cell free filtrates collected from R. trifolii cultured in association with the host roots induced branching in white clover root hairs. A partially purified preparation of the branching factor was obtained from freeze-dried filtrates by ethanol extraction and ion exchange chromatography. Preliminary studies on the characteristics of these substances suggest that some are dialyzable and heat stable white others are non-dialyzable and heat labile. The dialyzable, heat-stable compounds contain neutral sugars and range between 1200 to 10000 daltons in size. In roots that were exposed to low concentrations (6–25 μg-ml^?1) of these partially purified deformation factors before inoculation, the developmentally mature root hairs were deformed at the time of inoculation. Nodules appeared in the mature and immature root hair region of these plants at the same time. In plants exposed to water, nodules were observed in the immature root hair region and mature root hair regions 3 and 5 days after inoculation, respectively. Based on these results, we conclude that the nodule development was hastened in the plants exposed to the root hair-deforming substances because the mature root hairs of these plants were made infectible at the time of inoculation by this exposure.     

Mouse favus due to trichophyton quinckeanum (ZOPF) mac leod & muende: A reappraisal in the light of recent investigations. III

Summary and conclusions Sections of necropsy material of scutulum-bearing lesions from a kitten spontaneously infected byT. quinckeanum were stained by P.A.S., Sacpic and haematoxylin to reveal various features of the scutulum and the reaction which the parasite provoked in the tissues of the host.Such sections showed that the scutulum and other fungal structures were strongly Schiff positive.They also showed that, although the parasite was confined to the outermost layer of the epidermis (stratum corneum) it was also capable of invading the hair shaft and inner follicle sheath and of producing arthrospores both within the hair shaft and outside it (ecto-endothrix).The main inflammatory response of the host to the invasion of this organism showed itself in the massive infiltration of the dermal and epidermal tissues in the affected areas by serous exudate and polymorphonuclear leucocytes; other features being the undermining of the scutulum by pools of pus, the formation of discrete perifollicular microabscesses in the dermis, the engorgement of capillaries and oedema and lastly the parakeratosis.Necropsy sections from lesions of mice likewise experimentally infected by this dermatophyte showed much the same features as those found in the necropsy material of the spontaneously infected kitten.Necropsy sections from lesions of guinea-pigs experimentally infected by this organism showed incipient scutulum formation much infiltrated by inflammatory exudate and polymorphonuclear leucocytes. The dermis was also heavily infiltrated and showed perifollicular-abscesses. These sections also revealed invasion of the hair follicles and hair shaft by the dermatophyte.     

Membrane transport and cytokinin action in root hairs of Medicago sativa

In an effort to develop a cellular model for studying cytokinin action in higher plants, we investigated the effect of cytokinins on growth and membrane transport in root hairs of alfalfa (Medicago sativa␣L.) seedlings. Alfalfa seedlings grown for 24 h in the presence of cytokinins showed increased root hair length and formation of root hairs close to the root cap. Increased growth of root hairs was observed within 10 min of cytokinin application and was accompanied by a hyperpolarization of the plasma membrane. The ion-transport inhibitor diisothiocyanostilbene-2,2′-disulfonic acid (DIDS) blocked both cytokinin-induced root hair growth and hyperpolarization but did not, by itself, alter growth or membrane potential. Finally, hyperpolarization was induced by extracellular cytokinin but not by injection of cytokinin into the cytoplasm. These findings show that root hairs undergo several rapid responses to cytokinin, including changes in membrane transport and growth. We conclude that multiple cytokinin response in root hairs may be mediated by events involving perception and ion transport at the plasma membrane. Received: 18 July 1996 / Accepted: 1 October 1996     

Characterization of Hair Follicle Development in Engineered Skin Substitutes

Generation of skin appendages in engineered skin substitutes has been limited by lack of trichogenic potency in cultured postnatal cells. To investigate the feasibility and the limitation of hair regeneration, engineered skin substitutes were prepared with chimeric populations of cultured human keratinocytes from neonatal foreskins and cultured murine dermal papilla cells from adult GFP transgenic mice and grafted orthotopically to full-thickness wounds on athymic mice. Non-cultured dissociated neonatal murine-only skin cells, or cultured human-only skin keratinocytes and fibroblasts without dermal papilla cells served as positive and negative controls respectively. In this study, neonatal murine-only skin substitutes formed external hairs and sebaceous glands, chimeric skin substitutes formed pigmented hairs without sebaceous glands, and human-only skin substitutes formed no follicles or glands. Although chimeric hair cannot erupt readily, removal of upper skin layer exposed keratinized hair shafts at the skin surface. Development of incomplete pilosebaceous units in chimeric hair corresponded with upregulation of hair-related genes, LEF1 and WNT10B, and downregulation of a marker of sebaceous glands, Steroyl-CoA desaturase. Transepidermal water loss was normal in all conditions. This study demonstrated that while sebaceous glands may be involved in hair eruption, they are not required for hair development in engineered skin substitutes.     

Trichome studies in Parthenium hysterophorus and their taxonomic importance

In Parthenium hysterophorus L. four trichome types i.e. (1) cylindrical hair, (2) moniliform hair, (3) simple multiseriate hair and (4) shaggy hair, have been recognized mostly on the basis of their structural differences. In the past, these types have not been observed in any species of Parthenium studied so far. Out of these four, two types i.e. cylindrical and moniliform hairs are known to occur in the Compositae and remaining two i.e. simple multiseriate and shaggy hairs are the new forms for the family and have been observed for the first time in presently investigated species. Trichomes are an important taxonomic tool in distinguishing between genera and species. Trichomes of the different species of Parthenium as noticed from their structure are useful in distinguishing these species and even their corresponding organs.     

Morphological synergism in root hair length,density, initiation and geometry for phosphorus acquisition in Arabidopsis thaliana: A modeling approach

Low phosphorus availability regulates root hair growth in Arabidopsis by (1) increasing root hair length, (2) increasing root hair density, (3) decreasing the distance between the root tip and the point at which root hairs begin to emerge, and (4) increasing the number of epidermal cell files that bear hairs (trichoblasts). The coordinated regulation of these traits by phosphorus availability prompted us to speculate that they are synergistic, that is, that they have greater adaptive value in combination than they do in isolation. In this study, we explored this concept using a geometric model to evaluate the effect of varying root hair length (short, medium, and long), density (0, 24, 48, 72, 96, and 120 root hairs per mm of root length), tip to first root hair distance (0.5, 1, 2, and 4 mm), and number of trichoblast files (8 vs. 12) on phosphorus acquisition efficiency (PAE) in Arabidopsis. SimRoot, a dynamic three-dimensional geometric model of root growth and architecture, was used to simulate the growth of Arabidopsis roots with contrasting root hair parameters at three values of phosphorus diffusion coefficient (D _e=1×10^–7, 1×10^–8, and 1×10^–9 cm² s^–1) over time (20, 40, and 60 h). Depzone, a program that dynamically models nutrient diffusion to roots, was employed to estimate PAE and competition among root hairs. As D _e decreased from 1×10^–7 to 1×10^–9 cm² s^–1, roots with longer root hairs and higher root hair densities had greater PAE than those with shorter and less dense root hairs. At D _e=1×10^–9 cm² s^–1, the PAE of root hairs at any given density was in the order of long hairs > medium length hairs > short hairs, and the maximum PAE occurred at density = 96 hairs mm^–1 for both long and medium length hairs. This was due to greater competition among root hairs when they were short and dense. Competition over time decreased differences in PAE due to density, but the effect of length was maintained, as there was less competition among long hairs than short hairs. At high D _e(1×10^–7 cm² s^–1), competition among root hairs was greatest among long hairs and lowest among short hairs, and competition increased with increasing root hair densities. This led to a decrease in PAE as root hair length and density increased. PAE was also affected by the tip to first root hair distance. At low D _e values, decreasing tip to first root hair distance increased PAE of long hairs more than that of short hairs, whereas at high D _e values, decreasing tip to first root hair distance increased PAE of root hairs at low density but decreased PAE of long hairs at very high density. Our models confirmed the benefits of increasing root hair density by increasing the number of trichoblast files rather than decreasing the trichoblast length. The combined effects of all four root hair traits on phosphorus acquisition was 371% greater than their additive effects, demonstrating substantial morphological synergy. In conclusion, our data support the hypothesis that the responses of root hairs to low phosphorus availability are synergistic, which may account for their coordinated regulation.     

Hair embolism in lungs of rat and rabbit caused by intravenous injection

Among 1422 Sprague-Dawley rats treated daily for 28 consecutive days by i.v. injection, 144 animals (10.1%) showed particles of hair in thrombi at the site of injection. 381 rats (26.8%) had pulmonary emboli with fragments of hair and skin in arterial thrombi or in giant cell granulomas. 6 weeks after cessation of treatment lesions were still found in lungs from 5 of 90 rats (5.6%) allowed to recover. After the experimental administration of 0.75 ml/100 g body wt of a hair suspension (3000 hair particles/ml) to rats, there was no influence on phagocytosis whether endogenous or foreign hairs were injected. In 8 of 64 Himalayan rabbits (12.5%) given 28 injections each into ear veins pulmonary embolism was observed.     

Multiple cyclic nucleotide‐gated channels coordinate calcium oscillations and polar growth of root hairs

Calcium gradients underlie polarization in eukaryotic cells. In plants, a tip‐focused Ca²⁺‐gradient is fundamental for rapid and unidirectional cell expansion during epidermal root hair development. Here we report that three members of the cyclic nucleotide‐gated channel family are required to maintain cytosolic Ca²⁺ oscillations and the normal growth of root hairs. CNGC6, CNGC9 and CNGC14 were expressed in root hairs, with CNGC9 displaying the highest root hair specificity. In individual channel mutants, morphological defects including root hair swelling and branching, as well as bursting, were observed. The developmental phenotypes were amplified in the three cngc double mutant combinations. Finally, cngc6/9/14 triple mutants only developed bulging trichoblasts and could not form normal root hair protrusions because they burst after the transition to the rapid growth phase. Prior to developmental defects, single and double mutants showed increasingly disturbed patterns of Ca²⁺ oscillations. We conclude that CNGC6, CNGC9 and CNGC14 fulfill partially but not fully redundant functions in generating and maintaining tip‐focused Ca²⁺ oscillations, which are fundamental for proper root hair growth and polarity. Furthermore, the results suggest that these calmodulin‐binding and Ca²⁺‐permeable channels organize a robust tip‐focused oscillatory calcium gradient, which is not essential for root hair initiation but is required to control the integrity of the root hair after the transition to the rapid growth phase. Our findings also show that root hairs possess a large ability to compensate calcium‐signaling defects, and add new players to the regulatory network, which coordinates cell wall properties and cell expansion during polar root hair growth.     

Effects of substrate nitrate concentration on symbiotic nodule formation in actinorhizal plants

The response ofAlnus glutinosa, Casuarina cunninghamiana, Elaeagnus angustifolia andMyrica cerifera to a range of substrate nitrogen levels in solution, in relation to plant growth, infection, nodulation and root fine structure was studied. Nine concentrations of potassium nitrate ranging from 0.05 to 3.0 mM, were tested on each of the species. Plants were inoculated withFrankia pure cultures after a two week exposure to one of the nine levels of added nitrate. After six more weeks with constant exposure to nitrate, plants were harvested and assayed. With the exception of Myrica, regression analyses of whole plant dry weights as a function of added nitrate were highly significant. There was a tendency for nodulated plants grown at intermediate levels of added nitrate to exhibit higher relative growth rates, probably due to the additive effect of substrate nitrogen and fixation of atmospheric nitrogen. The mean numbers of nodules per plant were, with the exception of Alnus, significantly higher at intermediate levels of added nitrate, as were mean nodule dry weights. A highly significant inverse relationship between nodule weight as a percentage of whole plant weight was found in Elaeagnus and Myrica. The observed response of Elaeagnus to added nitrate compared to other actinorhizal plants appears to demonstrate that root hair infected plants are much more sensitive to the inhibitory effects of added nitrate than plants infected by intercellular penetration. A sharp reduction in the presence of root hairs at high concentrations of nitrate was observed. This indicates that the inhibition of nodulation in some actinorhizal plant species results from nitrate induced root hair suppression.