We compared Zic homologues from a wide range of animals. Striking conservation was found in the zinc finger domains, in which an exon-intron boundary has been kept in all bilateralians but not cnidarians, suggesting that all of the bilateralian Zic genes are derived from a single gene in a bilateralian ancestor. There were additional conserved amino acid sequences, ZOC and ZF-NC. Combined analysis of the zinc finger, ZOC, and ZF-NC revealed the presence of two classes of Zic, based on the degree of protein structure conservation. The "conserved" class includes Zic proteins from the Arthropoda, Mollusca, Annelida, Echinodermata, and Chordata (vertebrates and cephalochordates), whereas the "diverged" class contains those from the Platyhelminthes, Cnidaria, Nematoda, and Chordata (urochordates). The result indicates that the ancestral bilateralian Zic protein had already acquired an entire set of conserved domains, but that this was lost and diverged in the platyhelminthes, nematodes, and urochordates.

Lrfn2/SALM1 is a PSD-95-interacting synapse adhesion molecule, and human LRFN2 is associated with learning disabilities. However its role in higher brain function and underlying mechanisms remain unknown. Here, we show that Lrfn2 knockout mice exhibit autism-like behavioural abnormalities, including social withdrawal, decreased vocal communications, increased stereotyped activities and prepulse inhibition deficits, together with enhanced learning and memory. In the hippocampus, the levels of synaptic PSD-95 and GluA1 are decreased. The synapses are structurally and functionally immature with spindle shaped spines, smaller postsynaptic densities, reduced AMPA/NMDA ratio, and enhanced LTP. In vitro experiments reveal that synaptic surface expression of AMPAR depends on the direct interaction between Lrfn2 and PSD-95. Furthermore, we detect functionally defective LRFN2 missense mutations in autism and schizophrenia patients. Together, these findings indicate that Lrfn2/LRFN2 serve as core components of excitatory synapse maturation and maintenance, and their dysfunction causes immature/silent synapses with pathophysiological state.

A molecular phylogenetic analysis of luxA gene sequences of light organ symbionts of the fish Acropoma japonicum (Acropomatidae) and Siphamia versicolor (Apogonidae) revealed that the sequences were related to those of Photobacterium leiognathi ssp. mandapamensis, which is not known to occur as a light organ symbiont among bioluminescent P. leiognathi clades. The presence of another lux gene element, luxF, coding for nonfluorescent protein, provided additional support for the identity of the light organ symbionts of the fish. Cladogenesis of the light organ symbiont P. leiognathi may be influenced by the radiation of host fishes.

BackgroundDicyemid mesozoans (Phylum Dicyemida) are simple (8–40-cell) cephalopod endoparasites. They have neither body cavities nor differentiated organs, such as nervous and gastrointestinal systems. Whether dicyemids are intermediate between Protozoa and Metazoa (as represented by their "Mesozoa" classification) or degenerate species of more complex metazoans is controversial. Recent molecular phylogenetic studies suggested that they are simplified bilaterians belonging to the Lophotrochozoa. We cloned two genes developmentally critical in bilaterian animals (Pax6 and Zic), together with housekeeping genes (actin, fructose-bisphosphate aldolase, and ATP synthase beta subunit) from a dicyemid to reveal whether their molecular phylogeny supported the "simplification" hypothesis, and to clarify evolutionary changes in dicyemid gene structure and expression profiles.ResultsGenomic/cDNA sequence analysis showed that 1) the Pax6 molecular phylogeny and Zic intron positions supported the idea of dicyemids as reduced bilaterians; 2) the aa sequences deduced from the five genes were highly divergent; and 3) Dicyema genes contained very short introns of uniform length. In situ hybridization analyses revealed that Zic genes were expressed in hermaphroditic gonads, and Pax6 was expressed weakly throughout the developmental stages of the 2 types of embryo and in the hermaphroditic gonads.ConclusionThe accelerated evolutionary rates and very short and uniform intron may represent a part of Dicyema genomic features. The presence and expression of the two tool-kit genes (Pax6 and Zic) in Dicyema suggests that they can be very versatile genes even required for the highly reduced bilaterian like Dicyema. Dicyemids may be useful models of evolutionary body plan simplification.

Msx (/msh) family genes encode homeodomain (HD) proteins that control ontogeny in many animal species. We compared the structures of Msx genes from a wide range of Metazoa (Porifera, Cnidaria, Nematoda, Arthropoda, Tardigrada, Platyhelminthes, Mollusca, Brachiopoda, Annelida, Echiura, Echinodermata, Hemichordata, and Chordata) to gain an understanding of the role of these genes in phylogeny. Exon-intron boundary analysis suggested that the position of the intron located N-terminally to the HDs was widely conserved in all the genes examined, including those of cnidarians. Amino acid (aa) sequence comparison revealed 3 new evolutionarily conserved domains, as well as very strong conservation of the HDs. Two of the three domains were associated with Groucho-like protein binding in both a vertebrate and a cnidarian Msx homolog, suggesting that the interaction between Groucho-like proteins and Msx proteins was established in eumetazoan ancestors. Pairwise comparison among the collected HDs and their C-flanking aa sequences revealed that the degree of sequence conservation varied depending on the animal taxa from which the sequences were derived. Highly conserved Msx genes were identified in the Vertebrata, Cephalochordata, Hemichordata, Echinodermata, Mollusca, Brachiopoda, and Anthozoa. The wide distribution of the conserved sequences in the animal phylogenetic tree suggested that metazoan ancestors had already acquired a set of conserved domains of the current Msx family genes. Interestingly, although strongly conserved sequences were recovered from the Vertebrata, Cephalochordata, and Anthozoa, the sequences from the Urochordata and Hydrozoa showed weak conservation. Because the Vertebrata-Cephalochordata-Urochordata and Anthozoa-Hydrozoa represent sister groups in the Chordata and Cnidaria, respectively, Msx sequence diversification may have occurred differentially in the course of evolution. We speculate that selective loss of the conserved domains in Msx family proteins contributed to the diversification of animal body organization.

No abstract

To rapidly identify natural isolates of marine bioluminescent bacteria, we developed amplified ribosomal DNA restriction analysis (ARDRA) methods. ARDRA, which is based on the restriction patterns of 16S rRNA gene digested with five enzymes (EcoRI, DdeI, HhaI, HinfI, RsaI), clearly distinguished the 14 species of marine bioluminescent bacteria currently known, which belong to the genera Vibrio, Photobacterium, and Shewanella. When we applied ARDRA to 129 natural isolates from two cruises in Sagami Bay, Japan, 127 were grouped into six ARDRA types with distinctive restriction patterns; these isolates represented the bioluminescent species, P. angustum, P. leiognathi, P. phosphoreum, S. woodyi, V. fischeri, and V. harveyi. The other two isolates showing unexpected ARDRA patterns turned out to have 16S rRNA gene sequences similar to P. leiognathi and P. phosphoreum. Nevertheless, ARDRA provides a simple and fairly robust means for rapid identification of the natural isolates of marine bioluminescent bacteria, and is therefore useful in studying their diversity.

Background Pneumonia is a major cause of death in the elderly population. Considering body weight loss, muscle loss, and reflux after gastrectomy, elderly patients are considered to be at very high risk for pneumonia, which could decrease overall survival because early gastric cancer is mostly curable only by surgery. We aimed to clarify the incidence of pneumonia in the long-term period after gastrectomy in elderly patients who were diagnosed with early gastric cancer and its risk factors. Methods We retrospectively examined patients of > 75 years of age who underwent R0 gastrectomy for gastric cancer and who were diagnosed with T1 disease at National Cancer Center Hospital between 2005 and 2012. Long-term postoperative pneumonia was diagnosed by chest computed tomography every year until 2 years after surgery. The presence of preoperative sarcopenia was assessed using preoperative L3 skeletal muscle index. Results 167 patients were included in this study. Long-term postoperative pneumonia was observed in 44 (26%) patients. Of the 44 people diagnosed with long-term postoperative pneumonia, 33 were diagnosed in the 1st year and 11 in the 2nd year. 117 patients (70%) were diagnosed with sarcopenia which was significantly frequently found in the patients who developed long-term postoperative pneumonia (91%) than those without (63%). Preoperative sarcopenia was the only independent risk factor in multivariate analysis. Type of gastrectomy was not a significant risk factor. Conclusions Long-term postoperative pneumonia was frequently observed in the elderly patients. Preoperative sarcopenia was associated with long-term postoperative pneumonia in elderly patients who underwent curative surgery for gastric cancer. After gastrectomy, long-term special care would be required for elderly patients, especially with sarcopenia.