DNA-based identification of an echinoderm host for a deep-sea parasitic snail (Gastropoda: Eulimidae)

Eulimid gastropods (Caenogastropoda: Vanikoroidea) are exclusive parasites of echinoderms including all five classes of the phylum. However, many species have a long autonomous period and some tend to fall off the host during collection. This may result in a lack of host information for taxa, particularly those from the deep sea. The present study represents the first attempt to analyse the possible remains of host DNA in eulimid snails for a better understanding of their parasitic ecology. DNA extraction from the proboscis, polymerase chain reaction (PCR) with echinoderm-specific primers and sequencing of subclones successfully identified the ‘sea pig’, a holothurian of the genus Scotoplanes (Elasipodida: Elpidiidae) as the previously unknown host of Crinolamia sp. from bathyal depths off northern Japan. The morphological similarity between this eulimid and the type species of Crinolamia questions the alleged association of the latter with crinoids.     

A Novel Mouse Model of Soft-Tissue Infection Using Bioluminescence Imaging Allows Noninvasive,Real-Time Monitoring of Bacterial Growth

Musculoskeletal infections, including surgical-site and implant-associated infections, often cause progressive inflammation and destroy areas of the soft tissue. Treating infections, especially those caused by multi-antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Although there are a few animal models that enable the quantitative evaluation of infection in soft tissues, these models are not always reproducible or sustainable. Here, we successfully established a real-time, in vivo, quantitative mouse model of soft-tissue infection in the superficial gluteus muscle (SGM) using bioluminescence imaging. A bioluminescent strain of MRSA was inoculated into the SGM of BALB/c adult male mice, followed by sequential measurement of bacterial photon intensity and serological and histological analyses of the mice. The mean photon intensity in the mice peaked immediately after inoculation and remained stable until day 28. The serum levels of interleukin-6, interleukin-1 and C-reactive protein at 12 hours after inoculation were significantly higher than those prior to inoculation, and the C-reactive protein remained significantly elevated until day 21. Histological analyses showed marked neutrophil infiltration and abscesses containing necrotic and fibrous tissues in the SGM. With this SGM mouse model, we successfully visualized and quantified stable bacterial growth over an extended period of time with bioluminescence imaging, which allowed us to monitor the process of infection without euthanizing the experimental animals. This model is applicable to in vivo evaluations of the long-term efficacy of novel antibiotics or antibacterial implants.     

SMAP2 Regulates Retrograde Transport from Recycling Endosomes to the Golgi

Retrograde transport is where proteins and lipids are transported back from the plasma membrane (PM) and endosomes to the Golgi, and crucial for a diverse range of cellular functions. Recycling endosomes (REs) serve as a sorting station for the retrograde transport and we recently identified evection-2, an RE protein with a pleckstrin homology (PH) domain, as an essential factor of this pathway. How evection-2 regulates retrograde transport from REs to the Golgi is not well understood. Here, we report that evection-2 binds to SMAP2, an Arf GTPase-activating protein. Endogenous SMAP2 localized mostly in REs and to a lesser extent, the trans-Golgi network (TGN). SMAP2 binds evection-2, and the RE localization of SMAP2 was abolished in cells depleted of evection-2. Knockdown of SMAP2, like that of evection-2, impaired the retrograde transport of cholera toxin B subunit (CTxB) from REs. These findings suggest that evection-2 recruits SMAP2 to REs, thereby regulating the retrograde transport of CTxB from REs to the Golgi.     

Vetigastropod phylogeny and a new concept of Seguenzioidea: independent evolution of copulatory organs in the deep-sea habitats

Bayesian and maximum-likelihood phylogenies of Vetigastropoda (Mollusca: Gastropoda) were reconstructed by separate and combined analyses of one mitochondrial (cytochrome oxidase I, COI) and two nuclear (histone H3 and 18S rRNA) gene sequences, with an emphasis on dense taxonomic sampling. More than 70 vetigastropod species belonging to 13 families and 25 subfamilies constituted a robust clade against the two outgroup clades Neomphalina and Cocculinoidea. The phylogenetically controversial family Seguenziidae appeared as a derived Vetigastropoda and constituted a highly supported clade with eucycline and cataegine trochids, and three skeneimorphs ( Adeuomphalus , Ventsia and Xyloskenea ). These taxa herein treated as the superfamily Seguenzioidea are morphologically very diverse and grouped only by the combination of symplesiomorphies in the shell, radular and head-foot characters. Anatomical peculiarities of Seguenziidae, including the presence of the penis and seminal receptacle, are all apomorphic conditions independently derived from those in higher gastropod clades, as a consequence of the small size and in response to deep-sea habitats, where sperm storage seems to be especially beneficial with low numerical density of individuals and limited periodic cues for gametogenesis. Indeed, internal or semi-internal fertilization has been evolved at least six times in Vetigastropoda, essentially in deep-sea lineages, with weak phylogenetic constraints. Other new vetigastropod clades with high support values include: Turbinidae + Tegulinae (Trochidae) + Skeneidae s.s. , Clypeosectidae + Lepetodrilidae, Anatominae (Scissurellidae) +  Bathyxylophila (Skeneidae) and Lepetodriloidea + Scissurellidae + Bathyxylophila .     

Minute protrusions of the cuticle: Fine surface structures of the tunic in ascidians

The fine structure of the cuticular surface of the tunic was studied by scanning and transmission electron microscopy in 25 species belonging to 9 families of ascidians. The cuticular surface is ornamented with numerous minute protrusions in some species, but not in others. The minute protrusions are usually papillate in shape, and less than ～0.05 μm high (in some species of the families Polyclinidae and Polycitoridae), or ～0.1 μm high (in all species of Botryllidae, all colonial species of Styelidae and one solitary species of Pyuridae). In Clavelina miniata (Polycitoridae), the tunic is provided with parallel ridges on the surface of which papillate protrusions are distributed. The minute protrusions of Halocynthia roretzi (Pyuridae) are irregularly shaped, giving an appearance of paving stones. No protrusions are found in the families Didemnidae, Cionidae, Perophoridae, and Ascidiidae, and in one solitary species of Styelidae. At least in some colonial species, the density of the minute protrusions is lower at the edge of the colony than elsewhere. It is very probable that minute protrusions are found shortly after the secretion of tunic, growing larger both in size and in number as the tunic becomes older.     

Wound-induced Accumulation of Jasmonic Acid in Tissues of Potato Tubers

The level of jasmonic acid (JA) in medullary tissues of intactpotato tubers was found to be very low [ca. 4 ng (g fr wt)^–1].When the tissues were excised and incubated on moistened filterpaper, the level of JA began to increase rapidly, reached amaximum 4 h after excision and decreased thereafter. The maximumlevel of JA observed after 4 h was 450 ng (g fr wt)^–1.The level of JA-related compounds, as estimated by a bioassayfor potato tuber-inducing activity, showed similar fluctuationsto those in the level of JA, and neither methyl jasmonate nortuberonic acid could be detected in the tissues at any time.These results suggest that the increase in the level of JA isdue to the synthesis of JA and the decrease is due to the degradationof JA. The accumulation of JA was found only in tissues of dormanttubers that had been stored for less than 5 months and not inthose of sprouting tubers. Two inhibitors of animal phospholipaseA₂, namely, manoalide and quinacrine, did not inhibit the accumulationof JA, a result that suggests that activation of phospholipaseA₂ is not involved in the synthesis of JA. Actinomycin D andchloramphenicol also had no effect on the accumulation of JAbut cycloheximide had a considerable inhibitory effect. Theresults suggest that a newly synthesized protein(s) is the ratelimitingfactor in the biosynthesis of JA. (Received January 17, 1994; Accepted April 14, 1994)