The 'goatee' of goatfish: innervation of taste buds in the barbels and their representation in the brain

Goatfish use a pair of large chin barbels to probe the sea bottom to detect buried prey. The barbels are studded with taste buds but little else is known about the neural organization of this system. We found that the taste buds of the barbel are innervated in a strict orthogonal fashion. The barbel is innervated by a main nerve trunk running in the core of the barbel. A longitudinal nerve bundle originates from the main trunk and, after running a short distance distally, divides into two circumferential nerve bundles (CNB) extending respectively, medially and laterally around the barbel. Approximately 15 CNBs innervate each 1 mm length of barbel. At each transverse level, the CNB innervates two clusters of taste buds, each containing 14 end-organs. The primary taste centre in the brain is similarly extraordinary. The sensory inputs from the barbel terminate in a derived dorsal facial lobe, which has a highly convoluted surface forming a multitude of tubercles. Electrophysiological mapping experiments show that the entire barbel is somatotopically represented in a recurved elongate tubular fashion within the dorsal facial lobe.     

Contribution of cytokines on the suppression of lung metastasis

Weekly injection of a protein-bound polysaccharide PSK in mice with Lewis Lung Cancer (LLC) significantly decreased the number of lung metastatic foci concomitant with enhancement of cytostatic activity in the bronchoalveolar lavage (BAL) cells. These effects were more marked when the agent was given intratracheally, inducing a larger number of pulmonary macrophages, lymphocytes and neutrophils concomitant with increases in BAL tumor necrosis factor- (TNF-), mouse inflammatory protein- (MIP-1), mouse inflammatory protein- (MIP-1), interleukin-1 (IL-1) and interleukin-6 (IL-6), but not interleukin-2(IL-2) and interleukin-4 (IL-4). Pre-treatment with anti TNF- antibody reduced these effects. The time course and production of PSK-induced cytokines were similar between the tumor-bearing mice and control mice. BAL neutrophils in mice with LLC showed a tendency toward acceleration of O2- production compared with circulating neutrophils. Pulmonary macrophage phagocytosis was also significantly higher in the LLC mice.These results suggest that enhancement of cytostasis appears to be induced by activation and/or improvement of function in inflammatory and immune cells through cytokines under immunomodulator treatment in lung metastasis, possibly via a TNF--dependent mechanism.     

Adenovirus infection induces HuR relocalization to facilitate virus replication

HuR is an RNA-binding protein of the embryonic lethal abnormal vision (ELAV) family, which binds to the AU-rich element (ARE) in the 3′-untranslated region (UTR) of certain mRNAs and is involved in the nucleo-cytoplasmic export and stabilization of ARE-mRNAs. The cytoplasmic relocalization of ARE-mRNAs with several proteins such as HuR and pp32 increases in cells transformed by the adenovirus oncogene product E4orf6. Additionally, these ARE-mRNAs were stabilized and acquired the potential to transform cells. Although, the relocalization of HuR and the stabilization of ARE-mRNAs are crucial for cell transformation, evidence regarding the relationship of HuR and ARE-mRNAs with adenovirus replication is lacking. In this report, we demonstrate that adenovirus infection induces the relocation of HuR to the cytoplasm of host cells. Analysis using the luciferase-ARE fusion gene and the tetracycline (tet)-off system revealed that the process of stabilizing ARE-mRNAs is activated in adenovirus-infected cells. Heat shock treatment or knockdown-mediated depletion of HuR reduced adenovirus production. Furthermore, expression of ARE-including viral IVa2 mRNA, decreased in HuR-depleted infected cells. These results indicate that HuR plays an important role in adenovirus replication, at least in part, by up-regulating IVa2 mRNA expression and that ARE-mRNA stabilization is required for both transformation and virus replication.     

Calcitonin receptor and Odz4 are differently expressed in Pax7-positive cells during skeletal muscle regeneration

Satellite cells, muscle-specific stem cells, are anatomically identified as the mononuclear cells residing external to the myofiber plasma membrane and beneath the basal lamina. Skeletal muscle has great regenerative potential, and the regeneration process depends absolutely on satellite cells. In uninjured muscle, satellite cells are maintained in a quiescent state, and some genes are expressed in a quiescent-specific manner. Here we show that Odz4/Ten-m4, a mouse homolog of the Drosophila pair-rule gene odd Oz (odz or Ten-m), is expressed in quiescent satellite cells on the protein level, but not in activated/proliferating myoblasts. Intriguingly, the timing of the reappearance of Odz4 and calcitonin receptor (another quiescence molecule) on Pax7-positive cells was different during the regeneration process. In addition, almost all neonatal satellite cells express Odz4, but only some of them express calcitonin receptor. These results indicate that Odz4 may be useful as a new marker of satellite cells and that quiescence molecules are differently expressed in regenerating and neonatal muscle.     

Development of dorsal-ventral polarity in the optic vesicle and its presumptive role in eye morphogenesis as shown by embryonic transplantation and in ovo explant culturing

Dorsal and ventral specification in the early optic vesicle appears to play a crucial role in the proper development of the eye. In the present study, we performed embryonic transplantation and organ culturing of the chick optic vesicle in order to investigate how the dorsal-ventral (D-V) polarity is established in the optic vesicle and what role this polarity plays in proper eye development. The left optic vesicle was cut and transplanted inversely in the right eye cavity of host chick embryos. This method ensured that the D-V polarity was reversed while the anteroposterior axis remained normal. The results showed that the location of the choroid fissure was altered from the normal (ventral) to ectopic positions as the embryonic stage of transplantation progressed from 6 to 18 somites. At the same time, the shape of the optic vesicle and the expression patterns of Pax2 and Tbx5, marker genes for ventral and dorsal regions of the optic vesicle, respectively, changed concomitantly in a similar way. The crucial period was between the 8- and 14-somite stages, and during this period the polarity seemed to be gradually determined. In ovo explant culturing of the optic vesicle showed that the D-V polarity and choroid fissure formation were already specified by the 10-somite stage. These results indicate that the D-V polarity of the optic vesicle is established gradually between 8- and 14-somite stages under the influence of signals derived from the midline portion of the forebrain. The presumptive signal(s) appeared to be transmitted from proximal to distal regions within the optic vesicle. A severe anomaly was observed in the development of optic vesicles reversely transplanted around the 10-somite stage: the optic cup formation was disturbed and subsequently the neural retina and pigment epithelium did not develop normally. We concluded that establishment of the D-V polarity in the optic vesicle plays an essential role in the patterning and differentiation of the neural retina and pigment epithelium.     

Abrogation of neutral cholesterol ester hydrolytic activity causes adrenal enlargement

We have previously demonstrated that neutral cholesterol ester hydrolase 1 (Nceh1) regulates foam cell formation and atherogenesis through the catalytic activity of cholesterol ester hydrolysis, and that Nceh1 and hormone-sensitive lipase (Lipe) are responsible for the majority of neutral cholesterol ester hydrolase activity in macrophages. There are several cholesterol ester-metabolizing tissues and cells other than macrophages, among which adrenocortical cells are also known to utilize the intracellular cholesterol for steroidogenesis. It has been believed that the mobilization of intracellular cholesterol ester in adrenal glands was facilitated solely by Lipe. We herein demonstrate that Nceh1 is also involved in cholesterol ester hydrolysis in adrenal glands. While Lipe deficiency remarkably reduced the neutral cholesterol ester hydrolase activity in adrenal glands as previously reported, additional inactivation of Nceh1 gene completely abrogated the activity. Adrenal glands were enlarged in proportion to the degree of reduced neutral cholesterol ester hydrolase activity, and the enlargement of adrenal glands and the accumulation of cholesterol esters were most pronounced in the Nceh1/Lipe double-deficient mice. Thus Nceh1 is involved in the adrenal cholesterol metabolism, and the cholesterol ester hydrolytic activity in adrenal glands is associated with the organ enlargement.     

Transferrin polymorphisms in Japanese populations: north-south cline in the distribution of the TF*C2 allele

Allele frequencies for human transferrin (TF) subtypes were determined using serum samples from Japanese subjects living in Fukui prefecture, Japan, and compared with other Japanese populations using isoelectric focusing (IEF) and immunoblotting. The application of IEF revealed considerable heterogeneity in the TF system, enhancing its potential value for anthropologic and genetic studies. So far, TF subtypes of about 27,000 Japanese individuals from 35 population groups have been analyzed to evaluate the degree of genetic variation at the TF locus. Possible geographic and biologic factors are discussed.     

Cell-free translation system from Drosophila S2 cells that recapitulates RNAi

RNA interference (RNAi) is a fundamental mechanism of gene regulation in a variety of organisms. In Drosophila cells, long double-stranded RNAs (dsRNAs) are processed into 21- to 23-nucleotide double-stranded fragments, termed short interfering RNAs (siRNAs). The siRNAs trigger sequence-specific mRNA degradation, which results in the inhibition of gene expression. These phenomena can be recapitulated in vitro in lysates of Drosophila syncytial blastoderm embryos. In the present work, we used the common Drosophila cell line, Schneider Line 2 (S2), as a source to establish a cell-free translation system. We demonstrate here that the S2 cell-free translation system can recapitulate RNAi. Both long dsRNAs and siRNAs can trigger RNAi in this system, and the silencing effects are significant. This system should provide an important tool for biochemical analyses of the RNAi mechanism.     

Differential responses of rice to inoculation with wild-type and non-pathogenic mutants of Magnaporthe oryzae

We analyzed the response of rice to Magnaporthe oryzae infection using two mutant strains deficient in Mgb1 and Mst12, which are essential for the development of appresoria and penetration pegs. Both mutants induced the much lower levels of accumulation of phytoalexins than wild-type, suggesting that the massive production of phytoalexins requires the fungal invasion of rice cells. Intense accumulation of H₂O₂ in a single whole cell also required fungal penetration. Microarray analysis of rice gene expression revealed mutant-specific gene expression, indicating that signal exchange between rice and M. oryzae commence before fungal penetration of the rice cell. In situ detection of mRNAs for peroxidase and β-1,3-glucanase showed that expression of these genes also occurs after penetration as observed for phytoalexin production. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Tomoaki Kato, Shigeru Tanabe, and Marie Nishimura contributed equally to this work. Accession number of the original microarray data in NCBI is GSE9450.