Development of retinal layers

A noticeable characteristic of nervous systems is the arrangement of synapses into distinct layers. Such laminae are fundamental for the spatial organisation of synaptic connections transmitting different kinds of information. A major example of this is the inner plexiform layer (IPL) of the vertebrate retina, which is subdivided into at least ten sublayers. Another noticeable characteristic of these retina layers is that neurons are displayed in the horizontal plane in a non-random array termed as mosaic patterning. Recent studies of vertebrate and invertebrate systems have identified molecules that mediate these interactions. Here, we review the last mechanisms and molecules mediating retinal layering.     

Hyperpigmentation of Chinchilla Stria Vascularis Following Acoustic Trauma

This report describes morphological alterations of the chinchilla stria vascularis seen 30 days after exposure to impulse noise. The observed changes included a dramatic increase in strial melanin content which occurred in 7 of 36 animals exposed to electronically synthesized impulses presented in various temporal patterns at either 135 or 150 dB peak SPL. In these animals, densely pigmented areas of stria 1.5 to 3 mm in length were found in the basal cochlear turn. Light and electron microscopic study revealed that these areas contained large numbers of melanin granules situated primarily in pale-staining cells of the middle layer of the stria. Unlike the pigment granules present in normal chinchilla stria, the melanosomes found in the noise-exposed material clearly showed ultrastructural features characteristic of eumelanin. Melanin granules were also observed in marginal and basal cells of the noise-exposed stria. In some cases, pigment granules which had apparently been expelled from the marginal cells were present in the endolymphatic space beneath Reissner's membrane and on the strial surface. These findings support the view that the melanin-bearing cells of the inner ear are capable of markedly increased activity in response to stressful conditions.     

Keratinophilic fungi on the hair of goats from the West Bank of Jordan

The mycoflora of the hair in 178 goats from the West Bank of Jordan was analysed and the frequency of occurrence and the relative importance value for the different keratinophilic fungi found were calculated. One hundred and seven species which belong to 38 genera were isolated. Thirty six of these species were either well recognised agents of mycoses (Trichophyton mentagrophytes, T. verrucosum, and M. nanum), or have been frequently isolated from human and animal lesions (Arthroderma spp., Acremonium kiliense, Alternaria alternata, Aspergillus flavus, Cladosporium carionii, and several other species). These potentially pathogenic fungal species comprised 66.9% of all keratinophilic fungi found on the hair of goats. The role of this animal as a reservoir for dermatophytes and other potentially pathogenic fungi is discussed.     

One-Sided Barrier Impact of an International Railroad on Mongolian Gazelles

Abstract: We conducted a carcass census of Mongolian gazelles (Procapra gutturosa) along the Trans-Mongolian railroad in June 2005. We counted 241 gazelles that had died within the previous 12 months. Carcass numbers were greater on the southwestern side in the northern 3 zones, but we found carcasses only on the northeastern side in the southernmost zone. It suggests that impact of the railroad was stronger on one side and that the strength of this impact varied among regions.     

Spectrum structures and biological functions of 8-mers in the human genome

The spectra of k-mer frequencies can reveal the structures and evolution of genome sequences. We confirmed that the trimodal spectrum of 8-mers in human genome sequences is distinguished only by CG2, CG1 and CG0 8-mer sets, containing 2,1 or 0 CpG, respectively. This phenomenon is called independent selection law. The three types of CG 8-mers were considered as different functional elements. We conjectured that (1) nucleosome binding motifs are mainly characterized by CG1 8-mers and (2) the core structural units of CpG island sequences are predominantly characterized by CG2 8-mers. To validate our conjectures, nucleosome occupied sequences and CGI sequences were extracted, then the sequence parameters were constructed through the information of the three CG 8-mer sets respectively. ROC analysis showed that CG1 8-mers are more preference in nucleosome occupied segments (AUC > 0.7) and CG2 8-mers are more preference in CGI sequences (AUC > 0.99). This validates our conjecture in principle.