Predicting ecosystem changes by a new model of ecosystem evolution.

In recent years, computer simulation has been increasingly used to predict changes in actual ecosystems. In these studies, snapshots of ecosystems at certain points in time were instantly constructed without considering their evolutionary histories. However, it may not be possible to correctly predict future events unless their evolutionary processes are considered. In this study, we developed a new ecosystem model for reproducing the evolutionary process on an oceanic island, targeting Nakoudojima Island of the Ogasawara Islands. This model successfully reproduced the primitive ecosystem (the entire island covered with forest) prior to the invasion of alien species. Also, by adding multiple alien species to this ecosystem, we were able to reproduce temporal changes in the ecosystem of Nakoudojima Island after invasion of alien species. Then, we performed simulations in which feral goats were eradicated, as had actually been done on the island; these suggested that after the eradication of feral goats, forests were unlikely to be restored. In the ecosystems in which forests were not restored, arboreous plants with a high growth rate colonized during the early stage of evolution. As arboreous plants with a high growth rate consume a large amount of nutrient in soil, creating an oligotrophic state. As a result, plants cannot grow, and animal species that rely on plants cannot maintain their biomass. Consequently, many animals and plants become extinct as they cannot endure disturbances by alien species, and the ecosystem loses its resilience. Therefore, even if feral goats are eradicated, forests are not restored. Thus, the founder effect from the distant past influences future ecosystem changes. Our findings show that it is useful to consider the evolutionary process of an ecosystem in predicting its future events.

SCCmec typing of PVL-positive community-acquired Staphylococcus aureus (CA-MRSA) at a Japanese hospital.

The epidemiology of Panton-Valentine leukocidin (PVL)-positive MRSA in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) was examined. Three hundred and forty-two CA-MRSA strains that were susceptible to imipenem and cefazolin were isolated from 1107 samples (intravenous catheter, blood, sputum, urine, skin, wound, and pharynx) from outpatients at Showa University Hospital in Japan between September 2009 and March 2017. The PVL gene was detected in 46 of 342 CA-MRSA strains, accounting for 13.5%. The type of SCCmec was determined by detection of each SCCmec-specific region, class complex, and ccr. SCCmec type IV comprised 33 strains, type V comprised 5 strains, type VII comprised 4 strains, and the unclassified type comprised 4 strains. Among the type IV strains, subtype IVa was dominant, comprising 23 of 33 strains, and the remaining 10 strains were of varying subtypes. The SCCmec type III-specific region, CZ049, was amplified in 2 type V strains, 4 type VII strains, and 4 unclassified strains. In 4 unclassified strains, CZ049 and ccr5 were detected, but neither the SCCmec-specific region nor class complex was detected. The PVL-positive rate was lower than that in Western countries. The SCCmec types of PVL-positive CA-MRSA strains were found to vary, indicating a diverse spreading route.

Mapping the resilience of chemosynthetic communities in hydrothermal vent fields.

Hydrothermal vent fields are vulnerable to natural disturbances, such as volcanic activity, and are currently being considered as targets for mineral mining. Local vent communities are linked by pelagic larval dispersal and form regional metacommunities, nested within a number of biogeographic provinces. Larval supply depends on the connectivity of the dispersal networks, and affects recoverability of communities from disturbances. However, it is unclear how the dispersal networks contribute to recoverability of local communities. Here, we integrated a population dynamics model and estimation of large scale dispersal networks. By simulating disturbances to vent fields, we mapped recoverability of communities in 131 hydrothermal vent fields in the western Pacific Ocean. Our analysis showed substantial variation in recovery time due to variation in regional connectivity between known vent fields, and was not qualitatively affected by potential larval recruitment from unknown vent fields. In certain cases, simultaneous disturbance of a series of vent fields either delayed or wholly prevented recovery. Our approach is applicable to a dispersal network estimated from genetic diversity. Our method not only reveals distribution of recoverability of chemosynthetic communities in hydrothermal vent fields, but is also a practical tool for planning conservation strategies.

The contribution of seed dispersers to tree species diversity in tropical rainforests.

Tropical rainforests are known for their extreme biodiversity, posing a challenging problem in tropical ecology. Many hypotheses have been proposed to explain the diversity of tree species, yet our understanding of this phenomenon remains incomplete. Here, we consider the contribution of animal seed dispersers to the species diversity of trees. We built a multi-layer lattice model of trees whose animal seed dispersers are allowed to move only in restricted areas to disperse the tree seeds. We incorporated the effects of seed dispersers in the traditional theory of allopatric speciation on a geological time scale. We modified the lattice model to explicitly examine the coexistence of new tree species and the resulting high biodiversity. The results indicate that both the coexistence and diversified evolution of tree species can be explained by the introduction of animal seed dispersers.

Microhabitat locality allows multi-species coexistence in terrestrial plant communities.

Most terrestrial plant communities exhibit relatively high species diversity and many competitive species are ubiquitous. Many theoretical studies have been carried out to investigate the coexistence of a few competitive species and in most cases they suggest competitive exclusion. Theoretical studies have revealed that coexistence of even three or four species can be extremely difficult. It has been suggested that the coexistence of many species has been achieved by the fine differences in suitable microhabitats for each species, attributing to niche-separation. So far there is no explicit demonstration of such a coexistence in mathematical and simulation studies. Here we built a simple lattice Lotka-Volterra model of competition by incorporating the minute differences of suitable microhabitats for many species. By applying the site variations in species-specific settlement rates of a seedling, we achieved the coexistence of more than 10 species. This result indicates that competition between many species is avoided by the spatial variations in species-specific microhabitats. Our results demonstrate that coexistence of many species becomes possible by the minute differences in microhabitats. This mechanism should be applicable to many vegetation types, such as temperate forests and grasslands.

Properties of ecosystems that are vulnerable during eco-fusion.

When two ecosystems with separate evolutionary histories come into contact (eco-fusion), reciprocal invasions occur during their fusion. Asymmetries in the migration direction or extinction rate then occur (e.g., during the Great American Biotic Interchange, GABI). Hypotheses have been proposed to describe this process, but the ecosystem properties have not been adequately discussed. To identify the ecosystem properties that create vulnerability to species loss during eco-fusion, we conducted computer simulations of the fusion of ecosystems with independent evolutionary histories. With asymmetrical species extinction rates, the ecosystem with a higher extinction rate had a shorter food chain, a higher ratio of animal species to plant species, and a lower ratio of carnivores to herbivores. Most ecosystems that have undergone isolated evolution are vulnerable. These results may explain the vulnerability of South America's ecosystem during the GABI and that of modern Australia.

MLST analysis of multiple antimicrobial resistant Acinetobacter baumannii.

Multi-locus sequencing typing (MLST) of Acinetobacter baumannii, isolated at Showa University Hospital, was performed between November 2010 and March 2011. A. baumannii was isolated from 15 patients. Among the 15 isolates, the STs of three isolates were able to be determined, ST76, ST92, and ST146, and belonged to Clonal Complex (CC) 92, the global epidemic clone among carbapenem resistant A. baumannii. The other 12 strains were not applicable to the MLST classification. The ST76 strain was resistant to carbapenems, aminoglycosides, and fluoroquinolones. The ST92 strain was resistant to aminoglycosides and fluoroquinolones. The ST146 strain was resistant to fluoroquinolones. The other 12 strains were susceptible to either of the drugs. Neither the metallo beta lactamase gene (IMP type or VIM2) nor the OXA23 gene was detected in carbapenem resistant A. baumannii. These results indicate that A. baumannii of CC92 has spread as the drug resistant strain in Japan. Monitoring A. baumannii using molecular epidemiology is necessary.

Characterization of two mobilizable plasmids isolated from enterobacter cloacae.

We isolated two plasmids, pS51A and pS51B which were 5782 bp and 4854 bp in size, respectively, from the third generation cephalosporin-resistant E. cloacae suspected to express metallo-beta-lactamase, and analyzed their structures. These two plasmids encode RNA I/RNA II genes for replication origin, relaxase genes of mobABCD for plasmid transfer, and several open reading frames. According to the classification of mobilizable plasmids by gene organization of the relaxases, pS51A and pS51B belong to the ColE1 superfamily of mobilizable plasmids, commonly detected in Enterobacteriaceae. The metallo-beta-lactamase gene was not identified in either pS51A or pS51B by homology search of the putative open reading frames. Open reading frames encoded in pS51A include E. coli protein L-like, E. coli heat shock protein-like, and E. coli plasmid replication initiation protein-like, and those encoded in pS51B include helix-turn-helix protein-like, E. coli plasmid replication initiation protein-like, and Salmonella replication initiation protein-like. These plasmids are stably maintained in one strain of E. cloacae, thus, the encoded gene functions may confer growth advantage to the host cell.

Effect of cardiopulmonary bypass on cancer prognosis.

Adverse effects of cardiopulmonary bypass on cancer prognosis are expected but have not been confirmed. Seventy-four cancer patients who underwent cardiac surgery before cancer therapy were followed up for 42 ± 37 months; 45 had cardiac surgery with cardiopulmonary bypass. There was no significant difference in cancer recurrence (40.0%) and deaths (26.7%) among patients who had cardiopulmonary bypass and those who underwent off-pump cardiac surgery (27.6% and 24.1%). There were no significant differences in freedom from cancer-related death at 2 and 5 years after cardiac surgery (78.4% and 68.5%) in the cardiopulmonary bypass group compared to the 29 off-pump group (81.8% and 58.3%). Despite some limitations, this study detected no significant adverse effects of cardiopulmonary bypass on cancer prognosis. Although these results do not verify the safety of cardiopulmonary bypass from an oncologic aspect, they suggest it can be applied in cancer patients who require cardiac surgery.

Detection and temporal variation of (60)Co in the digestive glands of the common octopus, Octopus vulgaris, in the East China Sea.

(60)Co were detected in common octopus specimens collected in the East China Sea in 1996-2005. The source of (60)Co has remained unclear yet. Stable isotope analyses showed that there was no difference in stable Co concentrations between octopus samples with (60)Co and without (60)Co. This result showed that the stable Co in the digestive gland of octopus potentially did not include a trace amount of (60)Co and the source of (60)Co existed independently. Furthermore, investigations of octopus in other area and other species indicated that the origin of the source of (60)Co occurred locally in the restricted area in the East China Sea and not in the coastal area of Japan. Concentrations of (60)Co have annually decreased with shorter half-life than the physical half-life. This decrease tendency suggests that the sources of (60)Co were identical and were temporary dumped into the East China Sea as a solid waste.

Bone marrow large B cell lymphoma bearing cyclin D3 expression: clinical, morphologic, immunophenotypic, and genotypic analyses of seven patients.

We report seven large B cell lymphoma patients showing the involvement of tumor cells with cyclin D3 (CCND3) expression in bone marrow (BM) at the initial diagnosis. All patients presented with B symptoms, splenomegaly, and anemia/thrombocytopenia lacking hemophagocytosis in the BM. Five of the seven patients had suffered from immunological diseases or cancers. The tumor cells were divided into those with a lymphoplasmacytoid or blastoid appearance. Six cases were confirmed to express CD5 antigen on tumor cells. Three cases presented a chromosomal translocation between CCND3 and the immunoglobulin heavy chain (IGH) loci, t(6;14)(p21;q32). Three and two cases showed unmutated and mutated sequences of the variable region of IGH (VH), respectively, and one case showed deletion of an entire segment of VH. Two cases with t(6;14)(p21;q32) showed an unmutated VH sequence and chromosomal translocation within the switch region of IGH. Further studies are required to determine whether CCND3 expression is associated with a unique subset of diffuse large B cell lymphoma.

A molecular analysis of biclonal follicular lymphoma: further evidence for bone marrow origin and clonal selection.

We report a follicular lymphoma (FL) case presenting the coexistence of two tumor cell subpopulations in lymph node (LN) and bone marrow (BM), which exhibited an inverse pattern of immunoglobulin light (IgL) chain gene rearrangement and expression: Igkappa-lambda+ in LN and Igkappa+lambda- in BM. These tumor clones shared an identical BCL2-IgH recombination, accompanying t(14;18)(q32;q21) translocation, and an identical variable, diversity and joining segments joining with clone-specific VH somatic hypermutations on the untranslocated IgH allele. Our study provides further evidence that FL clones, originating from common progenitor cells, can be developed independently at different sites and with different IgL expression after immune selection.

The GAS5 (growth arrest-specific transcript 5) gene fuses to BCL6 as a result of t(1;3)(q25;q27) in a patient with B-cell lymphoma.

The BCL6 gene is frequently disrupted at its 5' noncoding region by 3q27 chromosomal translocations in B-cell lymphoma. As a result of translocation, BCL6 is juxtaposed to reciprocal partners, such as the immunoglobulin (Ig) gene family. Besides the Ig loci, multiple non-Ig partners of the BCL6 translocation have been reported. Here we describe the identification of the GAS5 (growth arrest-specific transcript 5) gene as a novel partner of the BCL6 in a patient with diffuse large B-cell lymphoma, harboring the t(1;3)(q25;q27). In this case, the chromosome 1 breakpoint was located within the intronic small nucleolar RNA (snoRNA) sequence of GAS5 and the chromosome 3 breakpoint at 4 kb upstream of BCL6 exon 1a. As the result of chromosomal translocation, the GAS5-BCL6 chimeric transcripts were expressed, in which the 5'-terminal oligopyrimidine (5'TOP) sequence of GAS5 was fused to the whole coding sequence of BCL6. The GAS5 gene on chromosome 1q25 is the second BCL6 partner, to the SNHG5 on 6q15, which is classified as a non-protein-coding multiple snoRNA host and 5'-TOP class gene.

On-pump beating-heart coronary artery bypass: a propensity matched analysis.

BACKGROUND: It remains unclear how cardioplegic arrest affects surgical results after coronary artery bypass grafting surgery (CABG). This study compares early outcomes after on-pump beating-heart CABG and conventional CABG. METHODS: From 2002 to 2005, 114 patients underwent on-pump beating-heart CABG. Multivariate logistic regression revealed five characteristics according to which technique is liable to be used: history of cerebral infarction, urgent or emergent operation, lower ejection fraction, preoperative creatine kinase, and lower number of diseased vessels. The early clinical outcome for these patients was compared against 114 conventional CABG patients, matched using a propensity score constructed with these five significant variables and with two nonsignificant variables: history of diabetes mellitus and hypertension. RESULTS: On-pump beating-heart CABG significantly reduced the duration of operation and cardiopulmonary bypass, total blood loss, and peak creatine kinase (p < 0.05). The number of patients requiring additional intra-aortic balloon pump support was significantly lower in the on-pump beating-heart CABG group (2 versus 13, p < 0.01). No patients required percutaneous cardiopulmonary support after on-pump beating-heart CABG, whereas 4 patients needed it after conventional CABG. Complete revascularization was significantly lower (42.1% versus 77.2%, p < 0.0001), but in-hospital mortality was less in the on-pump beating-heart CABG group (2.6% versus 9.6%, p < 0.05). No significant difference was found in morbidity including stroke, renal failure, mediastinitis, and prolonged ventilation. CONCLUSIONS: On-pump beating-heart CABG can be performed safely, including on high-risk patients. Use of cardiopulmonary bypass and the elimination of cardioplegic arrest may be of most benefit to hemodynamically unstable patients.

Lactate dehydrogenase-linked immunoglobulin Akappa in a patient with nonimmune chronic idiopathic neutropenia.

A 39-year-old patient with cervical cancer, stage Ia, was successfully treated by total hysterectomy. Then, after sustained neutropenia for more than 4 years and coincident with its exacerbation, the serum lactate dehydrogenase (LD) level started to elevate and reached a plateau. A test for antineutrophil antibody was negative and LD-3-linked IgAkappa, which may be responsible for high LD activity, was confirmed. The absolute number of blood NK cells was reduced, and a diagnosis of nonimmune chronic idiopathic neutropenia of adult was made. The successive occurrence of these 3 disorders may be based on interrelated immunological abnormalities.

Aortic valve replacement with a 16-mm CarboMedics valve in adult patients.

Management of the small aortic root is a significant problem for the surgeon with regard to operative technique and selection of the prosthesis. We report on four adults with a small aortic root who underwent aortic valve replacement with a 16-mm CarboMedics bileaflet valve. All patients now lead normal lives. Postoperative Doppler measurements demonstrated an acceptable transprosthetic gradient.

Serum levels of Thl/Th2 cytokines, angiogenic growth factors, and other prognostic factors in young adult patients with hemophagocytic syndrome.

Serum levels of T helper 1 (Th1)/T helper 2 (Th2) cytokines, angiogenic growth factors, and other prognostic factors were measured in 5 young adult patients with virus-associated hemophagocytic syndrome (HPS). Levels of 2 Th1 cytokines (interleukin [IL]-18 and tumor necrosis factor-alpha), 2 Th2 cytokines (IL-10 and IL-6), and 2 angiogenic growth factors (soluble intercellular adhesion molecule-1 and hepatocyte growth factor) were high in all of the patients examined, whereas those of Th1 cytokines such as IL-12 and macrophage inflammatory protein-1a were normal or low. Levels of IL-18 and IL-10 were highest in case 2, with a fatal outcome, and were lowest in case 4, with rapid recovery within 1 month. Although IFN-gamma levels were not elevated in 2 patients (cases 3 and 5), IL-18 levels were markedly high in both of these cases and the IL-6 level was highest in case 3. In contrast with the marked increase in the level of IL-10, the levels of IL-6, sIL-2R, and ferritin decreased rapidly and returned to normal within 2 months after therapy in case 3. The IL-18 level decreased somewhat, but remained elevated for 6 months, and the patient achieved a complete response within 11 months. Taken together, our findings suggest that both IL-18 and IL-10, but not IL-12, may play important roles in young adult patients with HPS via enhancing and suppressing Th1 immune responses, respectively.

[Diffuse large B-cell lymphoma with strongly positive MIB-1 stain and clinical features resembling Burkitt lymphoma].

A 62-year-old woman was admitted to our hospital because of gastric mucosal bleeding. Gastroendoscopy revealed a gastric tumor which was diagnosed from the biopsied specimen as diffuse large B-cell lymphoma (DLBCL). Lymphoma cells had infiltrated the bone marrow showed morphological features resembling Burkitt lymphoma (BL). Nearly 100% of the cells in the bone marrow were positive for MIB-1 immunostaining. The chromosomal study was normal. Surface marker analysis disclosed that the cells were positive for CD10, CD19, CD20 and CD25. As lymphoma cells had infiltrated the central nervous system, combined chemotherapy was performed accompanied with intrathecal administration of anticancer drugs. Although transient improvement was observed, the patient died of the advanced disease three months after admission. As we have shown here, there are some cases of DLBCL with immunohistochemical features resembling BL. Further consideration about the appropriate chemotherapy program for this type of disease might be necessary.