Differences in hair density of Japanese monkeys (Macaca fuscata fuscata) with locality and age

The hair density of free-ranging Japanese monkeys (Macaca fuscata fuscata) living in three different areas was investigated. The Japanese monkeys had thicker hair than other macaques. The hair density in the Japanese monkeys varied with locality: the northern monkeys had thicker hair than the southern ones. The density did not vary markedly with age up to 3 years of age, but then decreased gradually up to adult age (≧7 years old). The remarkable growth of the trunk suggested that the total number of hairs increased with age, especially during the period as a juvenile.     

Annual changes in hair length of the Japanese monkey (Macaca fuscata fuscata)

The hair length of Japanese monkeys was investigated for a period of one year and the molting phenomenon was clarified. Nine monkeys were employed in the study. The molting of the Japanese monkey was found to be of a seasonal type and occurred once during the year. The molting continued for one to four months in each monkey. The hair of the Japanese monkeys was wholly replaced during the period from April to August. The hair length was thus short in summer, and long in winter. Hair replacement in pregnant females began after parturition and was generally later than that in other individuals. During molting, both new and old hairs could be observed simultaneously in the same region of the body. The hair replacement ended around summer when the hair became the shortest. The new hairs continued to grow after molting and became the longest towards autumn or winter. Thus, the summer coat and the winter coat were essentially the same in the Japanese monkey. Such annual changes in the hair of the Japanese monkey were considered to be suitable for the climate of Japan.     

Characteristics of serial cross-sections of hairs of the Japanese monkey (Macaca fuscata fuscata)

The characteristics of serial cross-sections of hairs collected from an adult male Japanese monkey were investigated. Cross-sections were made of five to eight pieces per hair. The shapes of the cross-sections were elliptical or rounded on the whole. The fibre indices of the sections ranged from 83 to 100. In particular, those of proximal (basal) sections were close to 100. The hair diameter was 86.4 μ at maximum and 27.2 μ at minimum. A tendency was observed for the longer hairs to have thicker diameters. The changes in thickness along the fibre shaft were slightly different in relation to hair length. The thickest point was at around the middle of the fibre in the intermediate hair, somewhat towards the top of the central part in the long hair, and somewhat towards the base in the short hair. The hair of the Japanese monkey, however, was considered to be scanty in changes along the fibre shaft in comparison with many other animals. Medullae could scarcely be seen in the short hair and in the terminal and proximal sections of all hairs. Their shapes in cross-section were not uniform and rough at the margins. The fibre-medulla indices were generally less than 30 and smaller than those of many other mammals. Pigmentary granules were observed in all sections examined. The granules were black-grey in sections of the black-grey coloured part and yellow in the yellowish sections. They were dense in distal sections and scarce in sections close to the base. The cross-sectional appearance of the thickest part of the long hair was considered to be useful for hair identification, since it was good in pigmentation and medullation and relatively small fibre index.     

Morphological characteristics of the hair of Japanese monkeys (Macaca fuscata fuscata): Length,diameter and shape in cross-section,and arrangement of the medulla

A morphological study was carried out on hairs of the Japanese monkey. The shapes in cross-section were circles or ellipses. The diameters of the hairs ranged from 13.5 to 92 μ, and the mean value in each monkey was between about 30 and 40 μ. The average value of the fibre index was approximately 90 in each monkey. The arrangement of the medulla was considered to be of the narrow medulla lattice type. Medullae were developed poorly or disappeared in hairs with a diameter of less than 30 μ. A correlation was noted between the hair thickness and presence of medulla: medullated hairs were thicker than non-medullated hairs. A tendency was found for thicker hairs to be of greater length. The hairs of the Japanese monkey could be divided broadly into two types: medullated hair and non-medullated hair. The medullated hairs could be regarded as guard hair-like hairs since they were thick and long, and the non-medullated hairs as underhair-like hairs since they were thin and short.     

Comparison between the diameter of hair cross-sections and the thickness of the enclosed hairs in Japanese monkeys (Macaca fuscata fuscata)

The thickness of hairs from Japanese monkeys was measured by enclosing the hairs on slide glasses with balsam. Nine monkeys were used for the study. Forty to 69 hairs from the back were examined per head. High correlations between the thickness of the enclosed hairs and the diameter of cross-sections were obtained in all monkeys. In the Japanese monkey, therefore, it is considered possible to utilize enclosed hairs for measuring the thickness without preparing cross-sections. Moreover, the medullae of which the air layers are strongly related to thermoregulation, were readily observed in the enclosed hairs.     

Morphological changes in hair melanosomes by aging

Various changes appear in hair by aging, and graying is the most remarkable one. Changes in melanocytes have been well studied as the cause; however, little is known about the change in melanosomes which have a role of carrying melanin pigments into hair shafts. Using pigmented hairs of Japanese females from their age of 4–75, I isolated melanosomes and observed them. As a result, I found a significant change in the morphology of hair melanosomes with age. They were ellipsoidal on the whole and there was no age dependence in the major axis, while the minor axis significantly increased and its frequency distribution broadened with age. The anticipated volume of the melanosome of the oldest person hairs was about twice larger than that of child hairs. This enlargement of melanosome seems to be a cause of the age‐related color change in pigmented hairs from brown to black.     

Development of cricket sensory hairs: changes of dynamic mechanical properties

Summary Mechanical oscillation properties of cricket (Acheta domesticus) filiform hair sensilla were measured at different larval stages, as an indication of larval sensory capacities and for comparison with data in the literature on central nervous changes during development. The hairs were stimulated by airborne vibration over a frequency range of 10 to 220 Hz. Best frequency, angular displacement at best frequency, slope of angular-displacement tuning curve and phase of hair deflection relative to air particle velocity were tested for correlation with hair length, which is proportional to the age of a sensillum. The ranges found for the various oscillation parameters in early larval stages were similar to or larger than those in adults. Oscillation properties changed with both the developmental stage of the hair sensilla and that of the whole animal. Four individually identifiable hair sensilla were analysed separately; the sensory neurons of two of them are known to change synaptic properties during maturation. Angular displacement at a given stimulus intensity was maximal for all hairs after differentiation, and decreased during further development. The hairs did not show clear common changes for any of the other oscillation parameters. Yet particular changes were found for individual hairs.     

室内养殖雌性松鼠秋季换毛期被毛长度和保温性能变化

为了解松鼠东北亚种(Sciurus vulgaris manchuricus)秋季换毛期的被毛性状与保温性能变化的关系,选取2011年9月25日至12月15日期间采集的在哈尔滨室内人工养殖的27张雌性松鼠东北亚种生皮为材料,对背臀部毛皮样本进行传热性能测试,同时对该部位的披针毛、绒毛的长度和毛根出现无髓样本比例进行测量计算。结果表明:1)随着秋季换毛期的时间后移,新生冬毛长度不断增加,毛皮传热系数不断减小。当被毛生长结束时,保温性能达到恒定。2)披针毛长度、绒毛长度、披针毛毛根无髓段比例、绒毛毛根无髓段比例这4个被毛性状因子两两呈极显著正相关(P<0.01),且此4个性状因子皆与毛皮传热系数呈极显著负相关(P<0.01)。以上反映了在气温渐冷的秋季换毛期每时间阶段被毛的长度、生长程度、保温性能的具体变化及相互关系。     

The site of the action of the angora-Y gene and its interaction with the fuzzy-Y gene in the mouse

The site of action of the goY mutant gene was determined in the aggregation chimaeras C57BL-goY/goY----DBA (+/+). Chimerism was detected by mosaicism of coat pigmentation and electrophoretic pattern of glucose phosphate isomerase. In 28-day-old chimaeras the regions of light-brown coat alternated black coat, stripes of short hairs alternated those of long hairs. These stripes of different length and width extended from spine in lateral-ventral direction. The hairs plucked from long hairs stripes had a similar length that those of goY/goY mice of same age, but the hairs plucked from short hair stripes corresponded to the hair length of +/+ mice. These data show that the goY gene acts in epidermal cells of hair follicles and its expression is autonomous. It has been established that in double homozygotes goY/goYfzY/fzY both mutant genes are expressed: the considerable increase of hair length as compared to norm--the effect of the goY gene and curly coat--the effect of the fzY gene. In goY/goYfzY/fzY mice during the formation of G1 guard hairs the incomplete expression of the goY gene is observed that is due to the suppression of hair growth by the fzY mutant gene. The fzY gene does not suppress the growth of G2 hairs and therefore the full expression of the goY gene occurs in goY/goYfzY/fzY adult mice.     

马鹿东北亚种被毛形态结构的季节性差异

被毛作为哺乳动物特有的组织,具有保护和保温功能,一些季节性换毛动物需要通过更换被毛以适应冬季和夏季的不同环境（王泽长,1963;景松岩和张伟,1993）。因此,研究动物被毛结构与功能的季节性特征,对揭示被毛在物种生存和进化过程中的作用具有重要意义（张伟和徐艳春,2003）。对毛的结构多态性和功能多样性研究是国际毛发形态学研究中的前沿领域（Yalden,1985;Gaudette,1985;syred,1991;甘雅玲和郭中伟,2003;张伟和徐艳春,2003）。以往的毛发形态学研究多限于反映物种的特异性,并应用于分类鉴别方面（朱小曼,1987;张伟,1994;金煜,1995）。在强调毛发结构物种特异性的同时,忽略或淡化了其变异性,更缺少对结构和功能关系的研究。马鹿东北亚种（Cervus elaphus xanthopygus）为季节性换毛动物,绒毛退化,其被毛主要由上毛构成。本选择马鹿东北亚种的冬季和夏季上毛作为研究对象,初步测量了冬季和夏季其臀部、后肢上部、后肢下部及蹄部上毛的形态和微观结构数据,比较其季节性差异和部位差异。     

The efficiency of Arabidopsis thaliana (Brassicaceae) root hairs in phosphorus acquisition

Arabidopsis thaliana root hairs grow longer and denser in response to low-phosphorus availability. In addition, plants with the root hair response acquire more phosphorus than mutants that have root hairs that do not respond to phosphorus limiting conditions. The purpose of this experiment was to determine the efficiency of root hairs in phosphorus acquisition at high- and low-phosphorus availability. Root hair growth, root growth, root respiration, plant phosphorus uptake, and plant phosphorus content of 3-wk-old wild-type Arabidopsis (WS) were compared to two root hair mutants (rhd6 and rhd2) under high (54 mmol/m) and low (0.4 mmol/m) phosphorus availability. A cost-benefit analysis was constructed from the measurements to determine root hair efficiency. Under high-phosphorus availability, root hairs did not have an effect on any of the parameters measured. Under low-phosphorus availability, wild-type Arabidopsis had greater total root surface area, shoot biomass, phosphorus per root length, and specific phosphorus uptake. The cost-benefit analysis shows that under low phosphorus, wild-type roots acquire more phosphorus for every unit of carbon respired or unit of phosphorus invested into the roots than the mutants. We conclude that the response of root hairs to low-phosphorus availability is an efficient strategy for phosphorus acquisition.     

Stimulation of root hair elongation in Arabidopsis thaliana by low phosphorus availability

Low phosphorus availability stimulates root hair elongation in many plants, which may have adaptive significance in soil phosphorus acquisition. We investigated the effect of low phosphorus on the elongation of Arabidopsis thaliana root hairs. Arabidopsis thaliana plants were grown in plant culture containing high (1000 mmol m^?3) or low (1 mmol m^?3) phosphorus concentrations, and root hair elongation was analysed by image analysis. After 15d of growth, low-phosphorus plants developed root hairs averaging 0.9 mm in length while high-phosphorus plants of the same age developed root hairs averaging 0.3 mm in length. Increased root hair length in low-phosphorus plants was a result of both increased growth duration and increased growth rate. Root hair length decreased logarithmically in response to increasing phosphorus concentration. Local changes in phosphorus availability influenced root hair growth regardless of the phosphorus status of the plant. Low phosphorus stimulated root hair elongation in the hairless axr2 mutant, exogenously applied IAA stimulated root hair elongation in wild-type high-phosphorus plants and the auxin antagonist CM PA inhibited root hair elongation in low-phosphorus plants. These results indicate that auxin may be involved in the low-phosphorus response in root hairs.     

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.     

不同灌溉方式对玉米根毛生长发育的影响

在盆栽条件下,采用分根装置,在光学显微镜和电子显微镜下对均匀灌水、固定部分根区灌水和根系分区交替灌水3种方式下各1/2根区的根毛发育状况进行观察并采样照相,研究不同根区根毛的生长发育特征.结果表明：处理40 d时,固定部分根区灌水条件下,非灌水区的根毛有明显退化脱落现象,退化区所占比例为20.96%,明显大于其他根区;灌水区的根系发黄,有腐烂斑,且根分枝有退化现象,根毛密集区的密集程度不如非灌水区,但根毛退化区所占比例小（15.72%）,退化程度轻.均匀灌水根系的根毛发育状况与固定灌水的灌水区类似.交替灌水条件下,先灌水区和后灌水区根毛密集区的密集程度均较高,根毛退化脱落区分别占9.77%和10.38%,明显小于均匀灌水和固定灌水.说明采用交替灌水方式可促进根系根毛的生长发育,而持续湿润或干燥不利于根系根毛的生长发育.     

通河林区黄鼬(Mustela sibirica)冬季被毛形态结构的功能适应性

被毛在哺乳动物适应性进化过程中执行保温和保护两个重要功能,其形态结构上存在的功能适应性特征因所处的部位不同而表现出适应性分化现象,由动物体躯干至四肢末端呈显著的梯度变化。以黑龙江省通河林区黄鼬东北亚种(Mustela sibirica manchurica)冬季雌雄成体各10只完整毛皮对象,研究了背中部、腹中部和后肢下部3个部位的直针毛、披针毛、绒针毛、绒毛,以及后趾部硬毛的被毛性状因子,统计分析表明:通河林区黄鼬相同身体部位4种类型毛的长度和细度指标均为直针毛披针毛绒针毛绒毛,相同部位4种类型毛长度的相关性极显著,直针毛细度与披针毛细度相关性极显著(P0.01),绒针毛细度与绒毛细度相关性极显著(P0.01),这种特征使得被毛在整体结构上为实施保温和保护功能奠定基础;同时,黄鼬被毛各性状的保温功能从背部向后趾部呈递减趋势,而保护功能则呈现递增趋势,被毛形态结构性状上的分化与动物机体异温性充分结合,对于黄鼬适应寒冷的森林生态环境具有重要意义。     

Root hair length and rhizosheath mass depend on soil porosity,strength and water content in barley genotypes

Selecting plants with improved root hair growth is a key strategy for improving phosphorus-uptake efficiency in agriculture. While significant inter- and intra-specific variation is reported for root hair length, it is not known whether these phenotypic differences are exhibited under conditions that are known to affect root hair elongation. This work investigates the effect of soil strength, soil water content (SWC) and soil particle size (SPS) on the root hair length of different root hair genotypes of barley. The root hair and rhizosheath development of five root hair genotypes of barley (Hordeum vulgare L.) was compared in soils with penetrometer resistances ranging from 0.03 to 4.45 MPa (dry bulk densities 1.2–1.7 g cm^?3). A “short” (SRH) and “long” root hair (LRH) genotype was selected to further investigate whether differentiation of these genotypes was related to SWC or SPS when grown in washed graded sand. In low-strength soil (<1.43 MPa), root hairs of the LRH genotype were on average 25 % longer than that of the SRH genotype. In high-strength soil, root hair length of the LRH genotype was shorter than that in low-strength soil and did not differ from that of the SRH genotype. Root hairs were shorter in wetter soils or soils with smaller particles, and again SRH and LRH did not differ in hair length. Longer root hairs were generally, but not always, associated with larger rhizosheaths, suggesting that mucilage adhesion was also important. The root hair growth of barley was found to be highly responsive to soil properties and this impacted on the expression of phenotypic differences in root hair length. While root hairs are an important trait for phosphorus acquisition in dense soils, the results highlight the importance of selecting multiple and potentially robust root traits to improve resource acquisition in agricultural systems.     

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.     

The Effect of Nutrient Solution Composition on the Length of Root Hairs of Wheat (Triticum aestivum L.)

The length of root hairs of wheat (Triticum aestivum L.) growingin Long Ashton nitrate nutrient solution was affected mainlyby pH and the concentrations of calcium and nitrate. Root hairlength was decreased by high pH (> 7.0) and by low calciumconcentrations but was increased by nitrate. Buffering at pH6.5 was found to affect the relationship between nutrient solutionstrength and the length of root hairs. The interactions betweencalcium, nitrate and buffering were determined. Phosphate concentrationdid not affect the length of root hairs of wheat, although lowconcentrations have been reported to stimulate root hair growthin other plants. The mechanisms by which pH, calcium and nitratemay affect root hair length are discussed. Key words: Root hairs, Triticum aestivum, Wheat, Nutrient solutions     

Root hair formation and elongation of primary maize roots

In maize ( Zea mays L. cv. LG 11) roots cultured in humid air, the presence of hairs was not related to root growth. However, maximum hair length and length of the hair zone could be correlated to the elongation rate of the primary root. Under the growth conditions used, the emergence of root hairs always took place in the extending zone. In more basal regions, rhizodermal cells could not give rise to root hairs. Results were similar for roots preincubated in a buffer solution.     

Observations on root hair production by lucerne,maize and perennial ryegrass grown in a sandy loam

Summary Root hair production by young plants of lucerne, maize and perennial ryegrass grown in a sandy loam was assessed by examining roots growing at a soil-glass interface. Results are given for the percentage frequency distribution of root hair lengths and the numbers of root hairs produced per mm root. The mean lengths of root hairs observed on lucerne, maize and perennial ryegrass roots were 0.35, 0.90 and 1.12 mm respectively. Lucerne produced an average of 105 root hairs per mm of root, whereas maize produced 161 and perennial ryegrass produced 88. The total length of root hairs per mm length of root was estimated to be 37, 146 and 99 mm for lucerne, maize and perennial ryegrass resp. Letcombe Laboratory