Apical phosphatidylserine externalization in auditory hair cells

In hair cells of the inner ear, phosphatidylserine (PS), detected with fluorescent annexin V labeling, was rapidly exposed on the external leaflet of apical plasma membranes upon dissection of the organ of Corti. PS externalization was unchanged by caspase inhibition, suggesting that externalization did not portend apoptosis or necrosis. Consistent with that conclusion, mitochondrial membrane potential and hair-cell nuclear structure remained normal during externalization. PS externalization was triggered by forskolin, which raises cAMP, and blocked by inhibitors of adenylyl cyclase. Blocking Na⁺ influx by inhibiting the mechanoelectrical transduction channels and P2X ATP channels also inhibited external PS externalization. Diminished PS externalization was also seen in cells exposed to LY 294002, which blocks membrane recycling in hair cells by inhibiting phosphatidylinositol 3-kinase. These results indicate that PS exposure on the external leaflet, presumably requiring vesicular transport, results from elevation of intracellular cAMP, which can be triggered by Na⁺ entry into hair cells.     

The lateral line receptor array of cyprinids from different habitats

The lateral line system of teleost fishes consists of an array of superficial and canal neuromasts (CN). Number and distribution of neuromasts and the morphology of the lateral line canals vary across species. We investigated the morphology of the lateral line system in four diurnal European cyprinids, the limnophilic bitterling (Rhodeus sericeus), the indifferent gudgeon (Gobio gobio), and ide (Leuciscus idus), and the rheophilic minnow (Phoxinus phoxinus). All fish had lateral line canals on head and trunk. The total number of both, CN and superficial neuromasts (SN), was comparable in minnow and ide but was greater than in gudgeon and bitterling. The ratio of SNs to CNs for the head was comparable in minnow and bitterling but was greater in gudgeon and ide. The SN‐to‐CN ratio for the trunk was greatest in bitterling. Polarization of hair cells in CNs was in the direction of the canal. Polarization of hair cells in SNs depended on body area. In cephalic SNs, hair cell polarization was dorso‐ventral or rostro‐caudal. In trunk SNs, it was rostro‐caudal on lateral line scales and dorso‐ventral on other trunk scales. On the caudal fin, hair cell polarization was rostro‐caudal. The data show that, in the four species studied here, number, distribution, and orientation of CNs and SNs cannot be unequivocally related to habitat. J. Morphol. 275:357–370, 2014. © 2013 Wiley Periodicals, Inc.     

Terrestrial nest-building by wild chimpanzees (Pan troglodytes): implications for the tree-to-ground sleep transition in early hominins

Nest-building is a great ape universal and arboreal nesting in chimpanzees and bonobos suggests that the common ancestor of Pan and Homo also nested in trees. It has been proposed that arboreal nest-building remained the prevailing pattern until Homo erectus, a fully terrestrial biped, emerged. We investigated the unusual occurrence of ground-nesting in chimpanzees (Pan troglodytes), which may inform on factors influencing the tree-to-ground sleep transition in the hominin lineage. We used a novel genetic approach to examine ground-nesting in unhabituated chimpanzees at Seringbara in the Nimba Mountains, Guinea. Previous research showed that ground-nesting at Seringbara was not ecologically determined. Here, we tested a possible mate-guarding function of ground-nesting by analyzing DNA from shed hairs collected from ground nests and tree nests found in close proximity. We examined whether or not ground-nesting was a group-level behavioral pattern and whether or not it occurred in more than one community. We used multiple genetic markers to identify sex and to examine variation in mitochondrial DNA control region (HV1, HV2) sequences. Ground-nesting was a male-biased behavior and males constructed more elaborate ("night") nests than simple ("day") nests on the ground. The mate-guarding hypothesis was not supported, as ground and associated tree nests were built either by maternally-related males or possibly by the same individuals. Ground-nesting was widespread and likely habitual in two communities. We suggest that terrestrial nest-building may have already occurred in arboreally-adapted early hominins before the emergence of H. erectus.     

水稻无侧根突变体RM109的显微结构及其根毛形态观察

水稻原品种"大力"以NaN3诱变方法获得了稳定突变体RM109.显微结构观察表明,RM109种子根外表根毛稀少且短小,无侧根发生,而"大力"品种则有侧根发生,且密生根毛.根毛观察比较显示,距种子根根端1 cm处的RM109根毛数是"大力"品种的19%,差异极显著,根直径与"大力"品种差异不显著;距根端8 cm处的RM109根毛数和根直径分别是"大力"品种的45%和79%,二者差异极显著;距根端3 cm处,RM109最大根毛长是"大力"品种的33%,差异极显著;RM109种子根根端到根毛发生区的长度,与"大力"品种的差异不显著.     

Occurrence of heavy metals,sodium, calcium,and potassium in human hair,teeth, and nails

Heavy metals in biological samples: nails, teeth, and hair were examined during 1991–1993. Investigations of biological samples (hairn=249 samples, teethn=145, nailsn=80 samples) were provided for inhabitants of selected towns in Beskid Śląski. The towns are small mountain towns in southern Poland: Wista, Szczyrk, Istebna, Koniaków, and Jaworzynka. The analysis of ANOVA and MANOVA variances were used for biological samples in the context of age, sex, and type of samples for 12 elements (Pb, Cd, Cr, Zn, Fe, Cu, Mn, Ni, Co, Ca, Na, and K). The matrix correlation and cluster analysis were applied to explain the behavior of metals in human hair, teeth, and nails.     

Histological and enzyme histochemical investigation of the hemal nodes of the hair goat

Abstract

We investigated the structure of the hemal node in six healthy hair goats using histological and enzyme histochemical methods. After processing, tissue sections were stained with Crossman's trichrome, Gordon-Sweet's silver and Pappenheim's panoptic stains. Alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACP-ase) were demonstrated in frozen sections. Hemal nodes were encapsulated by connective tissue and few smooth muscle cells. Several trabeculae originated from the capsule and extended into the hemal node. A subcapsular sinus was present beneath the capsule and was continuous with the deeper sinuses. Subcapsular and deep sinuses were filled with erythrocytes. The parenchyma consisted of lymphoid follicles, diffuse interfollicular lymphocytes and irregular wide lymphoid cords. Cortical and medullary regions were not distinct. ANAE (+) and ACP-ase (+) cells were located mainly in the germinal centers of the lymphoid follicles and also were scattered equally in the interfollicular region and lymphoid cords. Monocytes, macrophages and reticular cells displayed a diffuse positive reaction, whereas localized granular positivity was observed in lymphocytes. We demonstrated that the general structure of the hair goat hemal nodes is similar to that of other ruminant species.     

MDR-like ABC transporter AtPGP4 is involved in auxin-mediated lateral root and root hair development

Previous data have suggested an involvement of MDR/PGP-like ABC transporters in transport of the plant hormone auxin and, recently, AtPGP1 has been demonstrated to catalyze the primary active export of auxin. Here we show that related isoform AtPGP4 is expressed predominantly during early root development. AtPGP4 loss-of-function plants reveal enhanced lateral root initiation and root hair lengths both known to be under the control of auxin. Further, atpgp4 plants show altered sensitivities toward auxin and the auxin transport inhibitor, NPA. Finally, mutant roots reveal elevated free auxin levels and reduced auxin transport capacities. These results together with yeast growth assays suggest a direct involvement of AtPGP4 in auxin transport processes controlling lateral root and root hair development.     

Melanocyte stem cells: a melanocyte reservoir in hair follicles for hair and skin pigmentation

Most mammals are coated with pigmented hair. Melanocytes in each hair follicle produce melanin pigments for the hair during each hair cycle. The key to understanding the mechanism of cyclic melanin production is the melanocyte stem cell (MelSC) population, previously known as 'amelanotic melanocytes'. The MelSCs directly adhere to hair follicle stem cells, the niche cells for MelSCs and reside in the hair follicle bulge-subbulge area, the lower permanent portion of the hair follicle, to serve as a melanocyte reservoir for skin and hair pigmentation. MelSCs form a stem cell system within individual hair follicles and provide a 'hair pigmentary unit' for each cycle of hair pigmentation. This review focuses on the identification of MelSCs and their characteristics and explains the importance of the MelSC population in the mechanisms of hair pigmentation, hair greying, and skin repigmentation.