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Rotavirus (RV) is a major pathogen causing severe diarrhea in infants and children aged less than 5 years. Vaccination is an economically feasible and effective strategy to prevent rotavirus infections. However, immune efficacy of live vaccines could be interfered by maternal antibodies and pre-existing antibodies of children. To develop an inactivated rotavirus vaccine (IRV), we had previously isolated a wild-type human rotavirus strain ZTR-68-A (G1P[8]) from the fecal samples of infants having severe diarrhea in a region endemic for the presence of this pathogen. In our present study, we assessed whether the presence of maternal and pre-existing antibodies in newborn BALB/c mice affected the immunogenicity of IRV administered to these animals. Our results indicate that maternal antibodies, generated from either vaccine immunization or rotavirus infection, showed partial influence with the immune responses generated by two doses of IRV vaccination. Increasing the number of immunizations can significantly improve the titer of serum neutralizing antibody and a seroconversion rate of up to 100%. In newborn mice, single-virus infection did not elicit detectable levels of serum neutralizing antibodies. After an IRV vaccination, the immune responses of these mice remained unaffected, with no significant differences in titers compared with those of control-group mice. In summary, choosing a suitable immunization dose and dosing frequency is essential for the immune effectiveness of IRV. The results of this study will provide animal experimental support for the IRV clinical research in future.

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The structure of an ecological community is shaped by diverse factors and processes, including competition for resources between species with similar ecological niches. Species coexistence in the face of competition is achieved by various mechanisms, such as niche partitioning, e.g. division of resources in space and time. We studied the effect of environmental variables on activity-density of the four lycosid species found in a Mediterranean shrubland in Israel, in the spring of 2012. We tested if spatial and temporal niche partitioning enables coexistence among the four ecologically similar lycosid spiders, using multivariate analyses (RDA, Species Response Curves and Trait Analysis (RLQ)) of vegetation structure, habitat characteristics and land use, as well as time in the season. Activity-density was significantly affected by time in the season and the interaction of time and geophyte density. These findings provide first insights into the life cycles of lycosid species in Mediterranean shrublands in Israel, with spider species of the same size-group reaching their activity peaks at different times.

The composition of plant communities everywhere now likely comprises alien as well as native species, and those aliens that become invasive have wide-ranging impacts on the structure and function of recipient ecosystems. These impacts include perturbations to soil carbon (C) cycling, but the direction and magnitude of impacts are species and climate dependent, making it difficult to generalize whether a specific invader will promote losses or gains in soil C stocks. Generalizations of a specific invader’s impacts are necessary; however, because the range of an invader can encompass thousands of square kilometers, meaning their effects can have broad, regional consequences. To quantify broad-scale and context-dependent impacts of a specific invader, multi-site investigations that capture and measure local and regional environmental heterogeneity are necessary. Using this approach, we show that a widespread grass invader of forest understories is associated with declines in soil C during infilling (spreading within the invaded range). Across the 36 study sites, total soil C stocks declined (P = 0.113) by approximately 12% (estimated mean ± SD, uninvaded: 2,429 ± 512.9 vs. invaded: 2,140 ± 520.7 g C m−2). The decline in total soil C is driven by a significant (P = 0.047) reduction in the native-derived, mineral-associated soil C fraction. This fraction, whose mass and slow turnover makes it an important C store, is approximately 15% lower in invaded (estimated mean ± SD: 1,560 ± 400.4 g C m−2) than uninvaded plots (1,826 ± 398.1 g C m−2). Notably, declines in this C fraction are only apparent at 21 of the sites, reflecting how environmental heterogeneity in other variables (specifically pH, soil moisture, and clay content) are important to quantify to determine invader impacts across a region. The 26% decline in microbial biomass with invasion (P = 0.011; estimated mean ± SD, uninvaded: 10.05 ± 1.79 vs. invaded: 7.40 ± 1.80 g C m−2) is also dependent on site characteristics (pH), and reductions are greater where the invader occurs at higher densities. Reductions in microbial biomass and soil C with invasion suggest that grass invasion will alter soil C cycling and decrease forest-C stores across the study region, although invader effects at a specific-site will be dependent on environmental context.

Exotic plant invasion not only changes native plant communities, it also alters associated arthropod community diversity and structure. These impacts often are contradictory and context-specific by study location. M. vimineum is an Asian grass currently invading the eastern United States that generally escapes herbivory. The invasion impacts on arthropod communities are mixed, and the effects on arthropod food webs are largely unknown. Because M. vimineum has a unique δ13C value, its carbon flow can be resolved from native plants in recipient food webs. We investigate arthropod communities at M. vimineum-invaded sites along a 100-km geographic and environmental gradient in the southeastern U.S. We investigate M. vimineum impacts on arthropod abundance and diversity, how M. vimineum-derived carbon contributes to arthropod biomass and how environmental variation modifies invasion effects on arthropod communities. We find that M. vimineum invasion corresponds with increased arthropod diversity and abundance, but reduced evenness. Herbivore damage to leaves is equivalent between native species and M. vimineum, but the type of herbivore damage is not the same between the native and invader plants. We also find that herbivores derive 37 % of their biomass-carbon from the exotic plant but predators almost none (4 %). Detritivores derive exotic carbon (9 %) proportional to M. vimineum in the litter layer. Whereas exotic plant impacts on arthropod communities often seem idiosyncratic by site, we find no context-dependent invasion effects of M. vimineum by study location. The consistency suggests that the impacts may be broadly generalizable, at least within well-established parts of the invasion range.

Background: In vitro studies have demonstrated that ciprofloxacin suppresses Escherichia coli attachment on stents, and ciprofloxacin has been shown to prolong stent patency in cats. However, clinical studies with antibiotic prophylaxis have produced conflicting results. The aim of this study was to isolate and identify the bacteria that attach early on unblocked stents removed from patients and to study their enzyme activities. Methods: Eighteen unblocked biliary stents were removed from 17 patients (benign obstruction in 14 and malignant obstruction in 4). All patients received antibiotic prophylaxis (mean of 6 days). Stents were in place for a mean of 33 days. The inside of stents was scraped and sludge was cultured aerobically and anaerobically. Identification of isolated bacteria and measurement of β-glucuronidase and phospholipase C activities were performed by using standard techniques. Gastric and duodenal juice from 18 patients with no biliary diseases was used as control samples. Results: All stents were patent and only 6 had visible sludge. There were 19 anaerobes isolated from 16 stents ( Clostridium perfringens 13, Clostridium bifermentans 4 and Bacteroides fragilis 2). Phospholipase C was detected in all Clostridium species. β-Glucuronidase was produced only by 12 of 13 C perfringens isolates. Sixteen aerobes including Enterococcus species and Bacillus species were isolated but none produced β-glucuronidase or phospholipase C. There were no aerobic gram-negative bacteria isolated from stents. Clostridium species and B fragilis were not recovered from the control samples. Conclusions: In patients who had received antibiotic prophylaxis against gram-negative bacterial infection, anaerobic bacteria may play a role in initiating stent blockage. (Gastrointest Endosc 2000;52:725-9.)

Widespread colonization by invasive species often obscures their underlying niche requirements. A robust inference into habitat requirements demands direct measures of invasive species performance linked with associated environmental conditions. In the context of general ecological theory, we investigated the niche requirements of Microstegium vimineum, an invasive grass in the U.S. that overruns native vegetation in forest understories. We examined M. vimineum's performance and reproduction as a function of environmental drivers across forested and unforested habitats along a 100-km regional and climatic gradient in the southeastern U.S. from the southern Appalachian Mountains to the Georgia piedmont. We then measured M. vimineum performance and reproduction in response to direct environmental drivers (diffuse light, litter cover, soil moisture, herbaceous cover, soil pH, clay content and temperature) in paired invaded and uninvaded plots. Lastly, we experimentally investigated recruitment in the context of experimental and natural disturbances. We find that all habitats are not equally suitable for M. vimineum—even those within which it occurs—and that the environmental conditions associated with roadsides and waterways are most suitable for M. vimineum persistence and spread. Microstegium vimineum's soil moisture, light and leaf litter requirements may delineate the boundaries of suitable habitat for the exotic invader. Significant decreases in M. vimineum recruitment, performance and reproduction along these environmental gradients suggest its potential niche limitations. Nevertheless, we also find significant dispersal limits on M. vimineum populations not subject to conspicuous overland water flow. We discuss our findings in the context of spread, impact and management of invasive species.