Bristle Hairs Research Articles

A new shrew mole species of the genus Uropsilus (Eulipotyphla: Talpidae) from northwestern Vietnam.

A new medium-sized shrew mole species of the genus Uropsilus from Mount Fansipan, Hoang Lien National Park, Lao Cai Province, northwestern Vietnam is described based on morphological and molecular differences. Uropsilus fansipanensis sp. nov. is distinguished from the other Uropsilus species by the combination of the following features: the dorsum is lightly reddish-brown and venter is dark gray; the dark gray tail is long and slender, with a scattered white base and short bristle hairs; orbital process is oriented upwards posteriorly; lacrimal foramen is well developed and much larger than infraorbital foramen; the lower first premolar is approximately the same size as the lower third premolar. Genetic distances in terms of mitochondrial cytochrome b from other Uropsilus species presented pairwise divergences from 8.63 to 20.70%. To date, the new species is known to exist only in the type locality of Mt. Fansipan, a wet and cold temperate climate area with an upper montane forest at an elevation of approximately 2900 m, forming the southernmost distribution of the genus Uropsilus.

Morphology and ultrastructure of the infrabuccal pocket in Strumigenys ants

The morphology of the infrabuccal pocket has been studied with light and electron microscopy (SEM, TEM) in 19 species of Strumigenys ants. The structural organization is similar in workers, queens and males, and supports the involvement of the pocket in the filtration of food particles before they can enter the digestive tract. A carpet of posteriorly oriented bristle hairs on the hypopharynx first guide ingested food into the pocket, where large solid particles are compacted into a pellet that will be regurgitated. The remaining products enter the digestive tract through a filtering wall of parallel hair combs lining the pharynx interior that are directed against the food flow. This mechanical filtering allows only liquids and sufficiently small food particles to enter the digestive system. The wall of the infrabuccal pocket is differentiated into a conspicuous glandular epithelium, of which the ultrastructural characteristics can be understood as an adaptation against the frequent shape changes of the pocket. The gland elaborates a non-proteinaceous secretion, although its functional significance still remains unknown.

Sexually dimorphic peripheral sensory neurons regulate copulation duration and persistence in male Drosophila

Peripheral sensory neurons are the gateway to the environment across species. In Drosophila, olfactory and gustatory senses are required to initiate courtship, as well as for the escalation of courtship patterns that lead to copulation. To be successful, copulation must last long enough to ensure the transfer of sperm and seminal fluid that ultimately leads to fertilization. The peripheral sensory information required to regulate copulation duration is unclear. Here, we employed genetic manipulations that allow driving gene expression in the male genitalia as a tool to uncover the role of these genitalia specific neurons in copulation. The fly genitalia contain sex-specific bristle hairs innervated by mechanosensory neurons. To date, the role of the sensory information collected by these peripheral neurons in male copulatory behavior is unknown. We confirmed that these MSNs are cholinergic and co-express both fru and dsx. We found that the sensory information received by the peripheral sensory neurons from the front legs (GRNs) and mechanosensory neurons (MSNs) at the male genitalia contribute to the regulation of copulation duration. Moreover, our results show that their function is required for copulation persistence, which ensures copulation is undisrupted in the presence of environmental stress before sperm transfer is complete.

QUALITY ASSESSMENT OF FUR VELOUR

The paper offers a quantitative assessment of the quality of fur velour made of raw sheepskin and nutria skins obtained by the developed technologies. For this purpose, hydrophobized fur velour made of semi-fine-wool sheep skins and nutria skins with low-quality bristle hair has been used. The tanned semi-finished product of sheepskin and male nutria after moisture removal has been processed with a grinding skin of 4-5 grit. Fur velour is obtained from raw materials of inhomogeneous structure in different topographic areas, low density, but with satisfactory physical and mechanical properties of leather fabric, which in its quality meets standards requirements. The hydrophobization process is carried out with a composition based on α-alkenes С20–24 and maleic anhydride with an average molecular weight of 38‧103. According to the purpose of the research, a comprehensive assessment of the quality level of hydrophobized fur velour has been performed. A number of tasks have been implemented. Individual indicators of fur velour have been selected and ranked by experts. Their significance has been determined. The range of dimensional indicators of fur velour quality has been pointed out according to the scale of desirability. Desirability functions of velour quality significant indicators and complex quality index (CQI) of hydrophobized fur velour have been developed. The results of CQI development of sheepskin and nutria skins hydrophobized fur velour have been analyzed. CQI of hydrophobized fur velor and nutria skins, which includes 10 significant experimentally determined indicators has been calculated. According to the CQI, the hydrophobized velour material significantly outperforms fur velour obtained by standard technologies, especially after its sprinkling. Hydrophobized velour of sheepskin and nutria is characterized by a higher thermal resistance of 1.17 and 1.15 times, respectively, in comparison with control samples. The obtained materials can be effectively used to manufacture clothing items suitable for use in extreme conditions under rain and snow.

Analysis of the hair coat of domestic cats with special focus on histological structure

The aim of the study was to characterize the hair coat of domestic cats. The research material consisted of hairs of different fractions collected in winter from female cats with a uniform hair coat colour: white,cream, red, brown and black. The hairs were divided into individual fractions, i.e. underhair, bristle hair and guard hair, and the following characteristics were evaluated: thickness, length, long and short axis length, stress at break and elongation. SEM (scanning electron microscope) images of all types of hair were taken and used to characterize each hair type and to calculate the number of scales per mm of hair length. The content of ions of various chemical elements was determined as well. Underhairs, which accounted for the largest percentage in the coat, were the thinnest and shortest, and had the most regular and distinct scale pattern. Guard hairs were the least numerous, but were the longest and thickest of all hairs examined. Both guard and bristle hairs had irregular scales with jagged edges. The cross-sections of these hairs revealed the presence of all the layers, i.e. the cuticle, cortex and medulla. In the underhair fraction the medulla was observed only in red cats. In all hairs the share of carbon, oxygen and sulphur ions was largest; these are the main omponents of hair protein, i.e. keratin.

An SEM image reference guide to hairs of 12 species of large African mammals

Abstract We developed a pictorial atlas of 52 scanning electron microscope (SEM) images of hairs found on 12 mammalian game species commonly found in the South African lowveld. Guard hairs were taken from the dorsoscapular, scapular, sternal, or axillary regions of each animal; and bristle hairs, if present, were collected from the manes of animals of each species. These images, along with other diagnostic features of hairs, can be used as an identification system. Such a system is useful for ecological studies where identifying animal remains is necessary.

Development and structure of internal glands and external glandular trichomes in Pogostemon cablin.

Pogostemon cablin possesses two morphologically and ontogenetically different types of glandular trichomes, one type of bristle hair on the surfaces of leaves and stems and one type of internal gland inside the leaves and stems. The internal gland originates from elementary meristem and is associated with the biosynthesis of oils present inside the leaves and stems. However, there is little information on mechanism for the oil biosynthesis and secretion inside the leaves and stems. In this study, we identified three kinds of glandular trichome types and two kinds of internal gland in the Pogostemon cablin. The oil secretions from internal glands of stems and leaves contained lipids, flavones and terpenes. Our results indicated that endoplasmic reticulum and plastids and vacuoles are likely involved in the biosynthesis of oils in the internal glands and the synthesized oils are transported from endoplasmic reticulum to the cell wall via connecting endoplasmic reticulum membranes to the plasma membrane. And the comparative analysis of the development, distribution, histochemistry and ultrastructures of the internal and external glands in Pogostemon cablin leads us to propose that the internal gland may be a novel secretory structure which is different from external glands.

Behavioral response to antennal tactile stimulation in the field cricket Gryllus bimaculatus

We examined behavioral responses of the field cricket Gryllus bimaculatus to tactile stimuli to the antennae. Three stimulants of similar shape and size but different textures were used: a tibia from the hunting spider Heteropoda venatoria (potential predator), a tibia from the orb-web spider Argiope bruennichi (less likely predator), and a glass rod. Each stimulus session comprised a first gentle contact and a second strong contact. The evoked behavioral responses were classified into four categories: aversion, aggression, antennal search, and no response. Regardless of the stimulants, the crickets exhibited antennal search and aversion most frequently in response to the first and second stimuli, respectively. The frequency of aversion was significantly higher to the tibia of H. venatoria than to other stimulants. The most striking observation was that aggressive responses were exclusive to the H. venatoria tibia. To specify the hair type that induced aggression, we manipulated two types of common hairs (bristle and fine) on the tibia of the predatory spider. When bristle hairs were removed from the H. venatoria tibia, aggression was significantly reduced. These results suggest that antennae can discriminate the tactile texture of external objects and elicit adaptive behavioral responses.

Light, conventional and environmental scanning electron microscopy of the trichomes of Cucurbita pepo subsp. pepo var. styriaca and histochemistry of glandular secretory products.

In the present study, the differences between glandular and non-glandular trichomes, the secretory process and the method of secretion were studied. Previous studies on leaves of Styrian oil pumpkin (Cucurbia pepo var. styriaca) plants have shown that four morphologically and ontogenetically independent glandular and non-glandular trichome types and one bristle hair type can be distinguished. The four types of trichomes can be categorized into three glandular trichome types: type I, a short-stalked trichome with four head cells including a 'middle-cell', two stalk cells and one basal cell; type II, a long-stalked trichome with two head cells, a 'neck-cell' region and a long stalk area; type IV, a 'stipitate-capitate' trichome with a mesophyll cell basement, a short stalk and a multicellular head; type III, a non-glandular 'columnar-digit' trichome, which consists of two head cells continuous with three-celled stalk, and the basal cell. The histochemical studies (the main classes of metabolite in secreted material of glandular trichomes) were conducted in fresh and fixed hand sections, using the following tests: Sudan black B, Nile blue A, osmium tetroxide, neutral red, Naturstoffreagent A, FSA (fuchsin-safranin-astra blue), NADI (naphthol + dimethylparaphenylenediamine) and ruthenium red. Each suggested differences in the intercalations during the ontogenetical development of each trichome during the development stage. The histochemical reactions revealed the main components of the materials secreted by all types of trichomes, which include lipids, flavones and terpenes and the different cell wall compositions. Glandular secretions were observed during environmental scanning electron microscopy (ESEM) and the trichomes compared with those seen by conventional scanning electron microscopy (CSEM). Scanning electron microscopy and histochemical analysis demonstrated that each of the trichomes studied produced and released secretory products in a characteristic way.

Hog Killing

Hog Killing The husbands stood in snow around the hog rose petals spreading toward their shoes a watercolor mimicry of first light waiting for the animal to finish to pass the ghost they smoked and blew their unrepentant noses. Wives brought wood, but only Uncle stacked it stick on stick, stirring up the ashes, demons spinning in the smoke that stuck to chins and lashes, then brought the scalder to a boil for scraping bristle hair from hide. Another hog was squealing, all the feeders cried. The long-armed Luckett sisters would clean the guts with hoses for stuffing with the baser cuts —no hams, no hooves— least that's what one supposes, then dipped the hog and shaved him till he looked like Uncle with his frown and hung him from the lintel of the barn, the dripping snout just off the ground. The wives said little to their husbands who said nothing to their wives. They worked him there, now warming up and talking, the steaming meat, the icy knives—the hog's feet spread on a singletree in most degrading poses— then cooked the skin and fat to lard as smoke and devils went into their eyes and up their unrepentant noses. -Ralph Price 18 ...

Location and dynamic properties of the spike generator in an insect mechanosensory neuron

1.The cereal bristle hairs of the cockroach, Periplaneta americana, are each innervated by one mechanosensory cell and 1–5 chemosensory cells. In transepithelial recordings, chemo- and mechanosensory spikes could be discriminated from each other by their relative amplitude. 2. When current steps were applied via the sensory hair, trains of impulses were triggered whatever the polarity of the current. 3. All responses adapted to the current, but the time course of adaptation was fitted by a power law for outward currents and an exponential law for inward currents. 4. During application of outward currents, the spikes showed a negative initial phase on which a small positive component was superimposed; strong polarizations produced purely negative spikes. More classical spikes with a positive initial phase were induced by inward currents. 5. The present work supports the hypothesis of a direct excitability of the apical dendrite in cereal bristle mechanoreceptors and confirms previous results suggesting that spikes are normally triggered within that region during mechanical stimulations. It is also established, for the first time, that adaptation to currents may be different in the apical dendrite and in more basal regions of the same mechanosensory neuron.

Initiation and conduction of impulses in mechanosensory neurons: Effects of hypoxia

1. 1. Extracellular recordings were made from cercal sensilla of Periplaneta americana. In bristle hair sensilla, mechanical stimulation induced biphasic spikes showing a negative initial phase on which a small positive deflection was superimposed. 2. 2. This sequence (the opposite of that observed in most insect sensilla) was inverted by repetitive stimulation or depolarization of the apical dendrite. 3. 3. In fliliform hair sensilla, the spikes were also biophasic but showed a positive leading phase. 4. 4. In vitro, spikes initiated in the sensilla rapidly failed to propagate along the sensory nerve unless the cercus was oxygenated. 5. 5. Invasion of the sensilla by antidromic spikes was also prevented by hypoxia. 6. 6. The conduction block occurred in the sensilla themselves rather than in the axons. 7. 7. Interpretation: sensory spikes are not initiated in the axon hillock but in the basal dendrite (filiform hair sensilla) or the apical dendriate (bristle hair sensilla); in the latter case, the trigger site can move from an apical to a basal location. 8. 8. After initiation, spikes are propagated towards the axon but they can be blocked by hypoxia at the dendrite-soma boundary.

A second cricket cereal sensory system: bristle hairs and the interneurons they activate

A new sensory system, in the abdomen of the cricketAcheta domesticus, is described. It consists of hair-like receptors, which we have called ‘bristles’, distributed on the cercus and abdomen. The sensory neurons, innervating bristles of a wide variety of shapes and sizes, project to a common area of the terminal abdominal ganglion. This region is distinct from the area called the cereal glomerulus which receives input from other receptor types. Three interneurons, whose dendrites are located exclusively in the projection area of bristle sensory neurons, are then described. These interneurons respond to tactile stimuli of the cercus and abdomen, but not to infrasound or to body orientation as do previously described interneurons. Based on the anatomical segregation of the afferents and interneurons, as well as the functional distinction from previously described cereal sensory systems, it is becoming clear that the cereal system is a multimodal sensory system.

The afferent projection of mesothoracic bristle hairs in the cricket,Acheta domesticus

One of the sensory systems of the thoracic segments of the cricket,Acheta domesticus, was investigated by using cobalt to stain the axonal arborizations of bristles of various types and locations. The results demonstrate that a variety of hair-like receptors project to the ventral areas of thoracic neuropil previously called ventral association center (VAC) and ventralmost ventral association center (vVAC). Bristles located on the dorsal thorax or wings arborize in or near VAC, while those on the ventral thorax and legs arborize in vVAC. Within the area of neuropil occupied by thoracic bristle afferents, the axonal arborizations are distributed according to the position of the parent receptor at the body surface; thus, medial afferents arborize medially and lateral ones more laterally. For leg afferents, the location of the axonal arborization is also correlated with the various leg segments of origin of the parent receptor and its circumferential location on that segment (Fig. 9).

On the dendritic topology and activation of cockroach giant interneurons

Each cercus of Periplaneta americana has 650 to 750 sensilla. The smaller cercal nerve contains about 1000 fibres; the larger contains about 2500. Many of these are under 0·5 μm in diameter. The sensilla found to be most effective in driving the giant fibres were cercal thread hairs and cercal bristle hairs. The cercal nerve tract leads directly into the dendritic trees of the giant interneurons. The dendritic trees of two giant interneurons were filled with Procion Yellow dye. Both display very extensive ipsilateral (to axon) ramification through a large volume of neuropile of the last abdominal ganglion. The location and extent of ramification of the two dendritic trees differs markedly, indicating that the two giant interneurons probably mediate different integrative activities. One of the giant fibres is attached to a single neuron soma, demonstrating that, at least in one case, the giant interneurons are not syncitial.