Poxvirus-encoded gamma interferon binding protein dampens the host immune response to infection

Ectromelia virus (ECTV), a natural mouse pathogen and the causative agent of mousepox, is closely related to variola virus (VARV), which causes smallpox in humans. Mousepox is an excellent surrogate small-animal model for smallpox. Both ECTV and VARV encode a multitude of host response modifiers that target components of the immune system and that are thought to contribute to the high mortality rates associated with infection. Like VARV, ECTV encodes a protein homologous to the ectodomain of the host gamma interferon (IFN-gamma) receptor 1. We generated an IFN-gamma binding protein (IFN-gammabp) deletion mutant of ECTV to study the role of viral IFN-gammabp (vIFN-gammabp) in host-virus interaction and also to elucidate the contribution of this molecule to the outcome of infection. Our data show that the absence of vIFN-gammabp does not affect virus replication per se but does have a profound effect on virus replication and pathogenesis in mice. BALB/c mice, which are normally susceptible to infection with ECTV, were able to control replication of the mutant virus and survive infection. Absence of vIFN-gammabp from ECTV allowed the generation of an effective host immune response that was otherwise diminished by this viral protein. Mice infected with a vIFN-gammabp deletion mutant virus, designated ECTV-IFN-gammabp(Delta), produced increased levels of IFN-gamma and generated robust cell-mediated and antibody responses. Using several strains of mice that exhibit differential degrees of resistance to mousepox, we show that recovery or death from ECTV infection is determined by a balance between the host's ability to produce IFN-gamma and the virus' ability to dampen its effects.     

Poxvirus CD8+ T-cell determinants and cross-reactivity in BALB/c mice

Mouse models of orthopoxvirus disease provide great promise for probing basic questions regarding host responses to this group of pathogens, which includes the causative agents of monkeypox and smallpox. However, some essential tools for their study that are taken for granted with other mouse models are not available for these viruses. Here we map and characterize the initial CD8+ T-cell determinants for poxviruses in H-2d-haplotype mice. CD8+ T cells recognizing these three determinants make up around 40% of the total responses to vaccinia virus during and after resolution of infection. We then use these determinants to test if predicted conservation across orthopoxvirus species matches experimental observation and find an unexpectedly cross-reactive variant peptide encoded by ectromelia (mousepox) virus.     

Colonization of woody seedlings in the understory of actively and passively restored tropical moist forests

The status of woody seedling colonization gives clues about the self‐sustainability of restored forests, a tenet of restoration success. Little is known about woody seedling colonization in restored afrotropical forests. We evaluated effects of restoration methods (active vs. passive), sampling year, restoration age, and distance from old‐growth forests on seedling colonization in restored afrotropical moist forests. Seedlings were measured in 2011 and 2014 in 71 clusters of 284 permanent sampling plots (12.6 m² each) in actively (initially 3–16 years old) and 21 clusters of 63 plots in passively restored forests (initially 16 years old) in Kibale National Park, western Uganda. Seedlings were also measured in nearby old‐growth forests in three clusters of five plots in 2014. We determined species diversity, richness, abundance per plot, and species composition as measures of seedling colonization in restored and old‐growth forests. We found that diversity, richness, and abundance of seedlings were significantly higher in passively than actively restored forests. Diversity and richness but not abundance significantly increased between sampling years and with restoration age. Distance from old‐growth forests did not significantly affect diversity, richness, and abundance. Species composition of actively and passively restored forests was different from that of old‐growth forests after 19 years since restoration started. Our results show that passive restoration should be the preferred method for recovering afrotropical forests, and highlight the effect of continued management on biodiversity of restored forests.     

Bioconversion of waste office paper to gluconic acid in a turbine blade reactor by the filamentous fungus Aspergillus niger

Gluconic acid production was investigated using an enzymatic hydrolysate of waste office automation paper in a culture of Aspergillus niger. In repeated batch cultures using flasks, saccharified solution medium (SM) did not show any inhibitory effects on gluconic acid production compared to glucose medium (GM). The average gluconic acid yields were 92% (SM) and 80% (GM). In repeated batch cultures using SM in a turbine blade reactor (TBR), the gluconic acid yields were 60% (SM) and 67% (GM) with 80-100 g/l of gluconic acid. When pure oxygen was supplied the production rate increased to four times higher than when supplying air. Remarkable differences in the morphology of A. niger and dry cell weight between SM and GM were observed. The difference in morphology may have caused a reduction of oxygen transfer, resulting in a decrease in gluconic acid production rate in SM.     

Correlation mapping method for generating microcirculation morphology from optical coherence tomography (OCT) intensity images

Standard optical coherence tomography (OCT) in combination with software tools can be harnessed to generate vascular maps in vivo. In this study we have successfully combined a software algorithm based on correlation statistic to reveal microcirculation morphology on OCT intensity images of a mouse brain in vivo captured trans‐cranially and through a cranial window. We were able to estimate vessel geometry at bifurcation as well as along vessel segments down‐to mean diameters of about 24 μm. Our technique has potential applications in cardiovascular‐related parameter measurements such as volumetric flow as well as in assessing vascular density of normal and diseased tissue. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

In vitro culture of freshly isolated Trypanosoma brucei brucei bloodstream forms results in gene copy-number changes

Most researchers who study unicellular eukaryotes work with an extremely limited number of laboratory-adapted isolates that were obtained from the field decades ago, but the effects of passage in laboratory rodents, and adaptation to in vitro culture, have been little studied. For example, the vast majority of studies of Trypanosoma brucei biology have concentrated on just two strains, Lister 427 and EATRO1125, which were taken from the field over half a century ago and have since have undergone innumerable passages in rodents and culture. We here describe two new Trypanosoma brucei brucei strains. MAK65 and MAK98, which have undergone only 3 rodent passages since isolation from Ugandan cattle. High-coverage sequencing revealed that adaptation of the parasites to culture was accompanied by changes in gene copy numbers. T. brucei has so far been considered to be uniformly diploid, but we also found trisomy of chromosome 5 not only in one Lister 427 culture, but also in the MAK98 field isolate. Trisomy of chromosome 6, and increased copies of other chromosome segments, were also seen in established cultured lines. The two new T. brucei strains should be useful to researchers interested in trypanosome differentiation and pathogenicity. Initial results suggested that the two strains have differing infection patterns in rodents. MAK65 is uniformly diploid and grew more reproducibly in bloodstream-form culture than MAK98.     

Density‐dependent reproduction and pollen limitation in an invasive milkweed,Calotropis procera (Ait.) R. Br. (Apocynaceae)

Calotropis procera (Ait.) R.Br. (Apocynaceae), an invasive woody milkweed, has expanded its range in northern Australia affecting rangeland and pastoral productivity. While self‐compatibility should enhance the species range expansion, spread of C. procera is limited by the availability of larger wasp and bee species that are able to vector its solid pollinia. Pollination efficiency is thus likely dependent on both pollinator abundance and plant density. Calotropis procera flowers year round in Australia but fruiting is limited to the warm months of the year when pollinators are most abundant, indicating that seasonal regulation of reproduction may be due to pollinator limitation. We examine the propositions that C. procera reproduction is regulated by the interaction between plant population density and pollinator pressure and that low pollinator pressure causes low per capita plant fecundity. All pollinators belonged to Order Hymenoptera and pollinator composition was similar at six of the seven sites. Fruit production per plant (fecundity) was lower above and below intermediate densities (350–550 plants ha^?1) of flowering plants with evidence of a weak Allee effect at lower plant density. Pollinator visitation rates per plant were low at high and low plant densities, and greatest at intermediate densities, while pollen supplementation experiments showed that C. procera is pollen limited (Pollen Limitation Index_fruit = 0.9) even at intermediate densities. Pollen limitation caused by low pollinator pressure at low plant densities and pollinator satiation at high plant densities may account for these fruit production trends. Management should be conducted in the colder months when pollinator pressure is low and plants are not reproducing. In addition, where stand eradication cannot be achieved in one attempt, management should reduce flowering plants to below intermediate densities where the fecundity per plant is low.     

采矿业对赞比亚的社会经济及环境的影响

采矿业是赞比亚一类非常重要的工业 ,大量的开采和选矿作业给周边地区带来了严重的环境问题。导致了该区域内地表水、空气、土壤的污染 ,并对当地人民的身体健康带来威胁。本文主要分析铜矿开采业对赞比亚的社会经济及环境的影响 ,进一步探讨可以保持当地采矿业的可持续发展的有效措施。     

Evidence for Persistence of Ectromelia Virus in Inbred Mice,Recrudescence Following Immunosuppression and Transmission to Na?ve Mice

Orthopoxviruses (OPV), including variola, vaccinia, monkeypox, cowpox and ectromelia viruses cause acute infections in their hosts. With the exception of variola virus (VARV), the etiological agent of smallpox, other OPV have been reported to persist in a variety of animal species following natural or experimental infection. Despite the implications and significance for the ecology and epidemiology of diseases these viruses cause, those reports have never been thoroughly investigated. We used the mouse pathogen ectromelia virus (ECTV), the agent of mousepox and a close relative of VARV to investigate virus persistence in inbred mice. We provide evidence that ECTV causes a persistent infection in some susceptible strains of mice in which low levels of virus genomes were detected in various tissues late in infection. The bone marrow (BM) and blood appeared to be key sites of persistence. Contemporaneous with virus persistence, antiviral CD8 T cell responses were demonstrable over the entire 25-week study period, with a change in the immunodominance hierarchy evident during the first 3 weeks. Some virus-encoded host response modifiers were found to modulate virus persistence whereas host genes encoded by the NKC and MHC class I reduced the potential for persistence. When susceptible strains of mice that had apparently recovered from infection were subjected to sustained immunosuppression with cyclophosphamide (CTX), animals succumbed to mousepox with high titers of infectious virus in various organs. CTX treated index mice transmitted virus to, and caused disease in, co-housed naïve mice. The most surprising but significant finding was that immunosuppression of disease-resistant C57BL/6 mice several weeks after recovery from primary infection generated high titers of virus in multiple tissues. Resistant mice showed no evidence of a persistent infection. This is the strongest evidence that ECTV can persist in inbred mice, regardless of their resistance status.     

An on-line adaptive glucose feeding system incorporating patterns recognition for glucose concentration control in glutamate fermentations

In glutamate fermentation, intermittent feeding is the most widely used glucose feed strategy. This feeding strategy causes severe fluctuations of glucose concentration and osmotic pressure in fermentation broth, which deteriorates the viability of the cell and reduces glutamate production in turn. In order to maintain glucose concentration at stable and constant levels, an on-line prediction and feedback control system based an empiric mass balance model was developed. However, the control system did not work properly and sometimes glucose concentration could even decline to 0 level (glucose exhaustion), as the model parameter varies in different runs. As a result, a novel model-based adaptive feedback control system incoporating with an artificial neural network (ANN) based pattern reconition unit for on-line diagnosizing the fault of glucose exhaustion was proposed and applied for glutamate fermentation. This adaptive control system could accurately detect glucose exhaustion when it occurs, and then immediately updates the control parameter based on some pre-defined rule. With the proposed control system, glucose was automatically fed, and its concentration could be maintained at desired levels constantly. As a result, glutamate concentration was 17 ~ 30% higher than that of the traditional fermentations using the intermittent glucose feed strategy.