Vertical and horizontal distribution patterns of the giant sea anemone Heteractis crispa with symbiotic anemonefish on a fringing coral reef

The distribution patterns of the leathery sea anemone, Heteractis crispa, which contains an algal endosymbiont (zooxanthellae) and anemonefish, were investigated in relation to size distribution on a shallow fringing reef (3.2 ha, 0–4 m depth) in Okinawa, Japan. Individual growth and movements were also examined. Large individuals (>1,000 cm²) inhabited reef edges up to a depth of 4 m, while small anemone (<500 cm²) inhabited shallow reefs including inner reef flats. Individuals rarely moved, and their sizes were significantly correlated with their water depths. Growth of small anemones was negatively correlated with their distance from the reef edge, suggesting that reef edges provide more prey and lower levels of physiological stress. This study suggested that deep reef edges are suitable habitats for H. crispa. Large anemones were inhabited by large Amphiprion perideraion or large Amphiprion clarkii, both of which are effective defenders against anemone predators. Anemones that settle in deep reef edges may enjoy a higher survival rate and attain a large size because of their symbiotic relationship with anemonefish. However, early settlers do not harbor anemonefish. Their mortality rate would be higher in the deep edges than in shallow edges, the complicated topography of which provides refuge.     

Retinal Attachment Instability Is Diversified among Mammalian Melanopsins

Melanopsins play a key role in non-visual photoreception in mammals. Their close phylogenetic relationship to the photopigments in invertebrate visual cells suggests they have evolved to acquire molecular characteristics that are more suited for their non-visual functions. Here we set out to identify such characteristics by comparing the molecular properties of mammalian melanopsin to those of invertebrate melanopsin and visual pigment. Our data show that the Schiff base linking the chromophore retinal to the protein is more susceptive to spontaneous cleavage in mammalian melanopsins. We also find this stability is highly diversified between mammalian species, being particularly unstable for human melanopsin. Through mutagenesis analyses, we find that this diversified stability is mainly due to parallel amino acid substitutions in extracellular regions. We propose that the different stability of the retinal attachment in melanopsins may contribute to functional tuning of non-visual photoreception in mammals.     

Inhibition of Endothelial Cell Differentiation on a Glycosylated Reconstituted Basement Membrane Complex

The vascular basement membrane is involved in the regulation of endothelial cell differentiation. The accumulation of advanced glycosylation endproducts (AGEs) has been demonstrated on these basement membranes in patients with diabetes. We examined the effect of AGEs on endothelial cell behavior on reconstituted basement membrane, Matrigel. Human umbilical vein-derived endothelial cells (HUVECs) stopped proliferating and differentiated into capillary-like tube-shaped structures on Matrigel. Laminin antibody partially blocked this process. HUVECs cultured on glycosylated Matrigel, however, proliferated and formed a monolayer without tube formation. The inclusion of aminoguanidine, an inhibitor of AGE formation, during the glycosylation of Matrigel restored HUVEC differentiation. Although the laminin adsorbed onto the plastic culture wells promoted HUVEC attachment and spreading, glycosylated laminin reduced HUVEC attachment by 50% and abolished cellular spreading. These effects were restored by aminoguanidine. HUVEC attachment to glycosylated laminin was further reduced by AGE-modified albumin, poly I, acetylated low-density lipoprotein, or maleylated albumin, ligands for a scavenger receptor. Coating the culture dishes with the laminin peptides RGD, YIGSR, and SIKVAV supported the attachment of HUVECs that was unaffected by glycosylation. Results suggest that AGE accumulation on the basement membranes inhibits endothelial cell differentiation by impairing the normal interactions of endothelial cell receptors with their specific matrix ligands. This process may be involved in diabetic angiopathy.     

Androgen Regulates Gene Expression of Cytoskeletal Proteins in Adult Rat Motoneurons

Expression of β-actin and β-tubulin mRNA was examined in androgen-sensitive motoneurons of the spinal nucleus of the bulbocavernosus (SNB) in adult male rats by in situ hybridization histochemistry using complementary DNAs encoding chick β-actin and mouse β-tubulin, respectively. Both hybridizable β-actin and βtubulin mRNAs were localized in the somata and proximal dendrites of SNB motoneurons. Removal of androgen by castration significantly reduced the expression levels of both β-actin and β-tubulin mRNAs in the SNB motoneurons, whereas the changes were prevented by testosterone treatment. In contrast, castration or testosterone treatment induced little or no change in the expression levels of these mRNAs in the much less androgen-sensitive motoneurons of the retrodorsolateral nucleus (RDLN). These results suggest that androgen regulates the expression of β-actin and β-tubulin genes in the SNB motoneurons and may provide evidence for the molecular mechanisms of hormonally induced neuronal plasticity in the SNB motoneurons.     

Actions of an antispermatogenic, but non-mutagenic, indenopyridine derivative in mice and Salmonella typhimurium.

This paper describes a new antispermatogenic agent. Following single oral administration to mice, the indenopyridine derivative (4aRS,5SR,9bRS)-2-ethyl-1,3,4,4a,5,9b-hexahydro-7-methyl-5-p-tolyl-2H-indeno(1,2-c)pyridine hydrochloride, code No. 20-438, produced long-lasting inhibition of the spermatogenic process at dose levels of 10 mg/kg (1/40 of the lowest lethal dose) and higher. Testes weights were significantly reduced from days 2--217 after treatment, and no clear-cut evidence of a recovery was found during this time. The fertility of treated males was normal during the initial 2 weeks after treatment, followed by partial or total sterility in weeks 3--6, and incomplete recovery in weeks 7--29 after treatment. The antifertility effects were caused by maturation depletion of the germ cells, leading to oligospermia. The following rank of decreasing "susceptibility" of the germ cells was observed: Spermatocytes greater than early spermatids, intermediate spermatogonia greater than stem cells. Sperm and late spermatids were not affected. Despite the characteristic specific germ-cell pattern of antifertility effects, 20-438 showed neither indications of pre- and post-implantational dominant lethality, nor mutagenic potentiality as measured by cytogenetic analysis of spermatocytes or spermatogonia, the sperm abnormality assay, the micronucleus test, and the Salmonella assay. These data suggest that the action of 20-438, leading to oligospermia, does not involve genetic toxic effects.     

The stable maintenance system pem of plasmid R100: degradation of PemI protein may allow PemK protein to inhibit cell growth.

We constructed plasmids carrying heat-inducible pemI and pemK genes, which were fused with the collagen-lacZ sequence in frame. The PemK-collagen-LacZ (PemK*) protein produced from the fusion gene upon heat induction inhibited the growth of cells and killed most of the cells in the absence of the PemI protein but did not do so in the presence of the PemI protein. This supports our previous assumption that the PemK protein inhibits cell division, leading to cell death, whereas the PemI protein suppresses the function of the PemK protein. We also constructed the plasmid carrying the heat-inducible pem operon which consists of the intact pemI gene and the pemK gene fused with collagen-lacZ. The simultaneously induced PemI and PemK* proteins did not inhibit the growth of cells. However, the temperature shift to 30 degrees C after induction of both proteins at 42 degrees C caused inhibition of cell growth and death of most cells. This suggests that the PemI protein is somehow inactivated upon the arrest of de novo synthesis of the PemI and PemK* proteins, allowing the PemK* protein to function. We observed that the PemI-collagen-LacZ (PemI*) protein was degraded faster than the PemK* protein, perhaps by the action of a protease(s). In fact, the lon mutation, which caused no apparent degradation of the PemI* protein, did not allow the PemK* protein to function, supporting the suggestion described above. Instability of the PemI protein would explain why the cells which have lost the pem+ plasmid are preferentially killed.     

Role of the Nuclease Activities Encoded by Herpes Simplex Virus 1 UL12 in Viral Replication and Neurovirulence

Enzyme-dead mutations in the herpes simplex virus 1 UL12 gene that abolished its endo- and exonuclease activities only slightly reduced viral replication in cell cultures. However, the UL12 null mutation significantly reduced viral replication, suggesting that a UL12 function(s) unrelated to its nuclease activities played a major role in viral replication. In contrast, the enzyme-dead mutations significantly reduced viral neurovirulence in mice, suggesting that UL12 nuclease activities were critical for viral pathogenesis in vivo.     

Pre-treatment of recombinant mouse MFG-E8 downregulates LPS-induced TNF-α production in macrophages via STAT3-mediated SOCS3 activation

Milk fat globule-epidermal growth factor factor 8 (MFG-E8) regulates innate immune function by modulating cellular signaling, which is less understood. Herein, we aimed to investigate the direct anti-inflammatory role of MFG-E8 in macrophages by pre-treatment with recombinant murine MFG-E8 (rmMFG-E8) followed by stimulation with LPS in RAW264.7 cells and in peritoneal macrophages, isolated from wild-type (WT) or MFG-E8(-/-) mice. RAW264.7 cells and mouse peritoneal macrophages treated with rmMFG-E8 significantly downregulated LPS-induced TNF-α mRNA by 25% and 24%, and protein levels by 29% and 23%, respectively (P<0.05). Conversely, peritoneal macrophages isolated from MFG-E8(-/-) mice produced 28% higher levels of TNF-α, as compared to WT mice when treated with LPS. In in vivo, endotoxemia induced by intraperitoneal injection of LPS (5 mg/kg BW), at 4 h after induction, serum level of TNF-α was significantly higher in MFG-E8(-/-) mice (837 pg/mL) than that of WT (570 pg/mL, P<0.05). To elucidate the direct anti-inflammatory effect of MFG-E8, we examined STAT3 and its target gene, SOCS3. Treatment with rmMGF-E8 significantly induced pSTAT3 and SOCS3 in macrophages. Similar results were observed in in vivo treatment of rmMFG-E8 in peritoneal cells and splenic tissues. Pre-treatment with rmMFG-E8 significantly reduced LPS-induced NF-κB p65 contents. These data clearly indicated that rmMFG-E8 upregulated SOCS3 which in turn interacted with NF-κB p65, facilitating negative regulation of TLR4 signaling for LPS-induced TNF-α production. Our findings strongly suggest that MFG-E8 is a direct anti-inflammatory molecule, and that it could be developed as a therapy in attenuating inflammation and tissue injury.