Masseteric Nerve Injury Increases Expression of Brain-Derived Neurotrophic Factor in Microglia Within the Rat Mesencephalic Trigeminal Tract Nucleus

The distribution of brain-derived neurotrophic factor was examined in the rat mesencephalic trigeminal tract nucleus after transection and crush of the masseteric nerve. In the intact mesencephalic trigeminal tract nucleus, brain-derived neurotrophic factor was detected in small cells with fine processes. These cells and processes were occasionally located adjacent to tyrosine kinase B receptor-immunoreactive sensory neurons. The transection and crush of the masseteric nerve increased expression of brain-derived neurotrophic factor in the nucleus. The number and size of brain-derived neurotrophic factor-immunoreactive cells and processes were dramatically elevated by the nerve injury. As a result, the density of brain-derived neurotrophic factor-immunoreactive profiles in the mesencephalic trigeminal tract nucleus at 7 days after the injury was significantly higher compared with the intact nucleus. Double immunofluorescence method also revealed that brain-derived neurotrophic factor-immunoreactive cells were mostly immunoreactive for OX-42 but not glial fibrillary acidic protein. In addition, the retrograde tracing method demonstrated that brain-derived neurotrophic factor-immunoreactive cells and processes surrounded retrogradely labeled neurons which showed tyrosine kinase B receptor-immunoreactivity. These findings indicate that the nerve injury increases expression of brain-derived neurotrophic factor in microglia within the mesencephalic trigeminal tract nucleus. The glial neurotrophic factor may be associated with axonal regeneration of the injured primary proprioceptor in the trigeminal nervous system.     

Computational analysis suggests a highly bendable, fragile structure for nucleosomal DNA

Eukaryotic chromosomal DNA coils around histones to form nucleosomes. Although histone affinity for DNA depends on DNA sequence patterns, how nucleosome positioning is determined by them remains unknown. Here, we show relationships between nucleosome positioning and two structural characteristics of DNA conferred by DNA sequence. Analysis of bendability and hydroxyl radical cleavage intensity of nucleosomal DNA sequences indicated that nucleosomal DNA is bendable and fragile and that nucleosome positional stability was correlated with characteristics of DNA. This result explains how histone positioning is partially determined by nucleosomal DNA structure, illuminating the optimization of chromosomal DNA packaging that controls cellular dynamics.     

Mutations in cell elongation genes mreB,mrdA and mrdB suppress the shape defect of RodZ‐deficient cells

RodZ interacts with MreB and both factors are required to maintain the rod shape of Escherichia coli. The assembly of MreB into filaments regulates the subcellular arrangement of a group of enzymes that synthesizes the peptidoglycan (PG) layer. However, it is still unknown how polymerization of MreB determines the rod shape of bacterial cells. Regulatory factor(s) are likely to be involved in controlling the function and dynamics of MreB. We isolated suppressor mutations to partially recover the rod shape in rodZ deletion mutants and found that some of the suppressor mutations occurred in mreB. All of the mreB mutations were in or in the vicinity of domain IA of MreB. Those mreB mutations changed the property of MreB filaments in vivo. In addition, suppressor mutations were found in the periplasmic regions in PBP2 and RodA, encoded by mrdA and mrdB genes. Similar to MreB and RodZ, PBP2 and RodA are pivotal to the cell wall elongation process. Thus, we found that mutations in domain IA of MreB and in the periplasmic domain of PBP2 and RodA can restore growth and rod shape to ΔrodZ cells, possibly by changing the requirements of MreB in the process.     

The Distribution of Transient Receptor Potential Melastatin-8 in the Rat Soft Palate, Epiglottis, and Pharynx

Immunohistochemistry for transient receptor potential melastatin-8 (TRPM8), the cold and menthol receptor, was performed on the rat soft palate, epiglottis and pharynx. TRPM8-immunoreactive (IR) nerve fibers were located beneath the mucous epithelium, and occasionally penetrated the epithelium. These nerve fibers were abundant in the posterior portion of the soft palate and at the border region of naso-oral and laryngeal parts of the pharynx. The epiglottis was free from such nerve fibers. The double immunofluorescence method demonstrated that TRPM8-IR nerve fibers in the pharynx and soft palate were mostly devoid of calcitonin gene-related peptide-immunoreactivity (CGRP-IR). The retrograde tracing method also demonstrated that 30.1 and 8.7 % of sensory neurons in the jugular and petrosal ganglia innervating the pharynx contained TRPM8-IR, respectively. Among these neurons, the co-expression of TRPM8 and CGRP-IR was very rare. In the nodose ganglion, however, pharyngeal neurons were devoid of TRPM8-IR. Taste bud-like structures in the soft palate and pharynx contained 4–9 TRPM8-IR cells. In the epiglottis, the mucous epithelium on the laryngeal side had numerous TRPM8-IR cells. The present study suggests that TRPM8 can respond to cold stimulation when food and drinks pass through oral and pharyngeal cavities.     

Composition and oligosaccharides of a milk sample of the giant panda,Ailuropoda melanoleuca

A milk sample from a captive giant panda (Ailuropoda melanoleuca), obtained at 13 days postpartum, contained 7.1% protein, 1.6% carbohydrate, 10.4% lipid and 0.9% ash. The ratio of casein to whey proteins was 5.0:2.1. Sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) of the whey protein fraction showed the presence of at least two major proteins other than alpha-lactalbumin and beta-lactoglobulin. SDS-PAGE and urea-gel electrophoresis showed that alphas-casein is not a major component. The proportions of triacylglycerol, cholesterol, cholesterol esters and phospholipid were 90.5, 5.3, 0.96 and 3.1%, of the total lipid, respectively. The dominant saccharide in the panda milk was Gal(alpha1-3)Gal(beta1-4)Glc (isoglobotriose). The milk contained, in addition, lesser amounts of lactose, Gal(alpha1-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc (fucosyl isoglobotriose), Neu5Ac(alpha2-3)Gal(beta1-4)Glc (3'-N-acetylneuraminyl-lactose), Neu5Ac(alpha2-6)Gal(beta1-4)Glc (6'-N-acetylneuraminyl-lactose) and Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]Glc.     

Correlated clustering and virtual display of gene expression patterns in the wheat life cycle by large-scale statistical analyses of expressed sequence tags

Compared to rice, wheat exhibits characteristic growth habits and contains complex genome constituents. To assess global changes in gene expression patterns in the wheat life cycle, we conducted large-scale analysis of expressed sequence tags (ESTs) in common wheat. Ten wheat tissues were used to construct cDNA libraries: crown and root from 14-day-old seedlings; spikelet from early and late flowering stages; spike at the booting stage, heading date and flowering date; pistil at the heading date; and seeds at 10 and 30 days post-anthesis. Several thousand colonies were randomly selected from each of these 10 cDNA libraries and sequenced from both 5' and 3' ends. Consequently, a total of 116 232 sequences were accumulated and classified into 25 971 contigs based on sequence homology. By computing abundantly expressed ESTs, correlated expression patterns of genes across the tissues were identified. Furthermore, relationships of gene expression profiles among the 10 wheat tissues were inferred from global gene expression patterns. Genes with similar functions were grouped with one another by clustering gene expression profiles. This technique might enable estimation of the functions of anonymous genes. Multidimensional analysis of EST data that is analogous to the microarray experiments may offer new approaches to functional genomics of plants.     

Molecular identification of novel alpha- and gammaherpesviruses from cetaceans stranded on Japanese coasts

Herpesviral infections have been documented in some cetaceans; however, they have not yet been identified in species in the western North Pacific. In the present study, 178 tissue samples from 76 stranded cetacean individuals were tested for the presence of herpesviruses. Herpesvirus genomic DNA fragments surrounding the DNA polymerase gene were amplified in samples from four individuals. TA cloning and direct sequencing of these DNA fragments revealed the presence of two novel alphaherpesviruses, and two novel gammaherpesviruses in the four cetacean individuals. The alphaherpesviruses were associated with the lung tissue of a false killer whale (Pseudorca crassidens), and with the mucus of a melon-headed whale (Peponocephala electra). The gammaherpesviruses were found in the lymph tissues of a Stejneger's beaked whale (Mesoplodon stejnegeri) and a sperm whale (Physeter macrocephalus). The phylogenetic tree using amino acid sequences of the DNA polymerase gene supported the inclusion of the novel viruses identified here in a single monophyletic group containing alphaherpesviruses from other Atlantic cetacean species. Conversely, the novel gammaherpesviruses formed an independent clade distant from other known cetacean gammaherpesviruses.     

Increase of CGRP Expression in Motor Endplates Within Fore and Hind Limb Muscles of the Degenerating Muscle Mouse (<Emphasis Type="Italic">Scn8a</Emphasis><Superscript><Emphasis Type="Italic">dmu</Emphasis></Superscript>)

The distribution of calcitonin gene-related peptide (CGRP) was examined in skeletal muscles of fore and hind limb as well as in oral and cranio-facial regions of the degenerating muscle (dmu) mouse, which harbours a null mutation in the voltage-gated sodium channel gene Scn8a. In limb, oral and cranio-facial muscles of wild type mice, only a few motor endplates contained CGRP-immunoreactivity. However, many CGRP-immunoreactive motor endplates appeared in the triceps brachii muscle, the biceps brachii muscle, the brachialis muscle, and the gastrocnemius muscle of dmu mice. CGRP-immunoreactive density of motor endplates in the skeletal muscles was also elevated by the mutation. In these muscles, the atrophy of muscle fibers could be detected and the density of cell nuclei in the musculature increased. In the flexor digitorum profundus muscle, the flexor digitorum superficialis muscle, and the soleus muscle as well as in oral and cranio-facial muscles, however, the distribution of CGRP-immunoreactivity was barely affected by the mutation. The morphology of muscle fibers and the distribution of cell nuclei within them were also similar in wild type and dmu mice. In the lumbar spinal cord of dmu mice, CGRP-immunoreactive density of spinal motoneurons increased. These findings suggest that the atrophic degeneration in some fore and hind limb muscles of dmu mice may increase CGRP expression in their motoneurons.