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261.
Yovita S.P. Rahardjo Frans J. Weber Sebastiaan Haemers Johannes Tramper Arjen Rinzema 《Enzyme and microbial technology》2005,36(7):900-902
Aspergillus oryzae is commonly used in solid-state fermentation (SSF) and forms abundant aerial mycelia. Previously, we have shown that aerial mycelia are extremely important for the respiration of this fungus during growth on a wheat-flour model substrate. In this paper, we show that aerial mycelia of this fungus give a strong increase in fungal biomass and α-amylase production. Cultures of A. oryzae on wheat-flour model substrate produced twice the amounts of fungal biomass and α-amylase, when aerial mycelia were formed. Utilization of these findings in commercial solid-state fermenters requires further research; results from packed beds of grain indicate that aerial mycelia are of limited importance there. Probably, substrate pre-treatment and an increase in bed voidage are required. 相似文献
262.
Vajda I van Pelt J Wolters P Chiappalone M Martinoia S van Someren E van Ooyen A 《Biophysical journal》2008,94(12):5028-5039
Reverberating spontaneous synchronized brain activity is believed to play an important role in neural information processing. Whether and how external stimuli can influence this spontaneous activity is poorly understood. Because periodic synchronized network activity is also prominent in in vitro neuronal cultures, we used cortical cultures grown on multielectrode arrays to examine how spontaneous activity is affected by external stimuli. Spontaneous network activity before and after low-frequency electrical stimulation was quantified in several ways. Our results show that the initially stable pattern of stereotypical spontaneous activity was transformed into another activity pattern that remained stable for at least 1 h. The transformations consisted of changes in single site and culture-wide network activity as well as in the spatiotemporal dynamics of network bursting. We show for the first time that low-frequency electrical stimulation can induce long-lasting alterations in spontaneous activity of cortical neuronal networks. We discuss whether the observed transformations in network activity could represent a switch in attractor state. 相似文献
263.
Increased susceptibility to enemies following introduction in the invasive plant Silene latifolia 总被引:3,自引:1,他引:2
One of the influential hypotheses invoked to explain why species become invasive following introduction is that release from natural enemies favours a shift in investment from defence to traits enhancing growth and reproduction. Silene latifolia was introduced from Europe (EU) to North America (NA) c. 200 years ago where it experiences lower damage by natural enemies. A common garden experiment in EU using seeds from 20 EU and 20 NA populations revealed (1) genetically‐based differences in life history between plants from EU and NA; plants from NA have evolved a weedy phenotype that flowers earlier, and has a two‐ to threefold higher reproductive potential; (2) higher susceptibility of NA plants to fungal infection, fruit predation, and aphid infestation. These results suggest that the invasive NA phenotype has evolved at the expense of defensive abilities. Despite this increased susceptibility to enemies, NA populations still outperformed EU populations in this common garden. 相似文献
264.
Sai Thein Than Tun Lorenz von Seidlein Tiengkham Pongvongsa Mayfong Mayxay Sompob Saralamba Shwe Sin Kyaw Phetsavanh Chanthavilay Olivier Celhay Tran Dang Nguyen Thu Nguyen-Anh Tran Daniel M. Parker Maciej F. Boni Arjen M. Dondorp Lisa J. White 《Malaria journal》2017,16(1):483
Background
The number of Plasmodium falciparum malaria cases around the world has decreased substantially over the last 15 years, but with the spread of resistance against anti-malarial drugs and insecticides, this decline may not continue. There is an urgent need to consider alternative, accelerated strategies to eliminate malaria in countries like Lao PDR, where there are a few remaining endemic areas. A deterministic compartmental modelling tool was used to develop an integrated strategy for P. falciparum elimination in the Savannakhet province of Lao PDR. The model was designed to include key aspects of malaria transmission and integrated control measures, along with a user-friendly interface.Results
Universal coverage was the foundation of the integrated strategy, which took the form of the deployment of community health workers who provided universal access to early diagnosis, treatment and long-lasting insecticidal nets. Acceleration was included as the deployment of three monthly rounds of mass drug administration targeted towards high prevalence villages, with the addition of three monthly doses of the RTS,S vaccine delivered en masse to the same high prevalence sub-population. A booster dose of vaccine was added 1 year later. The surveillance-as-intervention component of the package involved the screening and treatment of individuals entering the simulated population.Conclusions
In this modelling approach, the sequential introduction of a series of five available interventions in an integrated strategy was predicted to be sufficient to stop malaria transmission within a 3-year period. These interventions comprised universal access to early diagnosis and adequate treatment, improved access to long-lasting insecticidal nets, three monthly rounds of mass drug administration together with RTS,S vaccination followed by a booster dose of vaccine, and screening and treatment of imported cases.265.
Plant chemical defense against herbivores and pathogens: generalized defense or trade-offs? 总被引:6,自引:6,他引:0
Plants are often attacked by multiple enemies, including pathogens and herbivores. While many plant secondary metabolites show specific effects toward either pathogens or herbivores, some can affect the performance of both these groups of natural enemies and are considered to be generalized defense compounds. We tested whether aucubin and catalpol, two iridoid glycosides present in ribwort plantain (Plantago lanceolata), confer in vivo resistance to both the generalist insect herbivore Spodoptera exigua and the biotrophic fungal pathogen Diaporthe adunca using plants from P. lanceolata lines that had been selected for high- and low-leaf iridoid glycoside concentrations for four generations. The lines differed approximately three-fold in the levels of these compounds. Plants from the high-selection line showed enhanced resistance to both S. exigua and D. adunca, as evidenced by a smaller lesion size and a lower fungal growth rate and spore production, and a lower larval growth rate and herbivory under both choice and no-choice conditions. Gravimetric analysis revealed that the iridoid glycosides acted as feeding deterrents to S. exigua, thereby reducing its food intake rate, rather than having post-ingestive toxic effects as predicted from in vitro effects of hydrolysis products. We suggest that the bitter taste of iridoid glycosides deters feeding by S. exigua, whereas the hydrolysis products formed after tissue damage following fungal infection mediate pathogen resistance. We conclude that iridoid glycosides in P. lanceolata can serve as broad-spectrum defenses and that selection for pathogen resistance could potentially result in increased resistance to generalist insect herbivores and vice versa, resulting in diffuse rather than pairwise coevolution. 相似文献
266.
Seasonal variation in daily activity patterns of free-ranging European ground squirrels (Spermophilus citellus) 总被引:1,自引:0,他引:1
Daily aboveground activity of European ground squirrels (Spermophilus citellus) in their natural habitat was recorded with a visual scanning procedure during the active seasons of 1992 and 1993. Activity patterns were analyzed with respect to time of year and to the animal's reproductive state. Aboveground activity started on average 3.9 h (SD 0.6 h, n = 37 days) after civil twilight at dawn and ended on average 3.2 h (SD 0.9 h, n = 37 days) before civil twilight at dusk. Between onset and offset of activity, 54% was spent aboveground, of which 73% was spent foraging. Activity patterns were influenced by photoperiod, rainfall, and by reproductive state. During mating, reproductively active males started activity earlier than females and reproductively inactive males. For females, time spent foraging was high during lactation. The midpoint of daily activity was at 12:16 h (SD 0.37 h, n = 37 days). Activity patterns of European ground squirrels thus appear robustly positioned in the middle of the photoperiod. 相似文献
267.
268.
We have isolated the Hansenula polymorpha ATG25 gene, which is required for glucose-induced selective peroxisome degradation by macropexophagy. ATG25 represents a novel gene that encodes a 45 kDa coiled-coil protein. We show that this protein colocalizes with Atg11 on a small structure, which most likely represents the pre-autophagosomal structure (PAS). In cells of a constructed ATG25 deletion strain (atg25) peroxisomes are constitutively degraded by nonselective microautophagy, a process that in WT H. polymorpha is only observed at nitrogen limitation conditions. This suggests that nonselective microautophagy is deregulated in H. polymorpha atg25 cells. 相似文献
269.
van Lent PL Nabbe KC Blom AB Sloetjes A Holthuysen AE Kolls J Van De Loo FA Holland SM Van Den Berg WB 《Arthritis research & therapy》2005,7(4):R885-R895
In previous studies we have found that FcγRI determines chondrocyte death and matrix metalloproteinase (MMP)-mediated cartilage
destruction during IFN-γ-regulated immune complex arthritis (ICA). Binding of immune complexes (ICs) to FcγRI leads to the
prominent production of oxygen radicals. In the present study we investigated the contribution of NADPH-oxidase-driven oxygen
radicals to cartilage destruction by using p47phox-/- mice lacking a functional NADPH oxidase complex. Induction of a passive ICA in the knee joints of p47phox-/- mice resulted in a significant elevation of joint inflammation at day 3 when compared with wild-type (WT) controls as studied
by histology. However, when IFN-γ was overexpressed by injection of adenoviral IFN-γ in the knee joint before ICA induction,
a similar influx of inflammatory cells was found at days 3 and 7, comprising mainly macrophages in both mouse strains. Proteoglycan
depletion from the cartilage layers of the knee joints in both groups was similar at days 3 and 7. Aggrecan breakdown in cartilage
caused by MMPs was further studied by immunolocalisation of MMP-mediated neoepitopes (VDIPEN). VDIPEN expression in the cartilage
layers of arthritic knee joints was markedly lower (between 30 and 60%) in IFN-γ-stimulated arthritic p47phox-/- mice at day 7 than in WT controls, despite significant upregulation of mRNA levels of various MMPs such as MMP-3, MMP-9,
MMP-12 and MMP-13 in synovia and MMP-13 in cartilage layers as measured with quantitative RT-PCR. The latter observation suggests
that oxygen radicals are involved in the activation of latent MMPs. Chondrocyte death, determined as the percentage of empty
lacunae in articular cartilage, ranged between 20 and 60% at day 3 and between 30 and 80% at day 7 in WT mice, and was completely
blocked in p47phox-/- mice at both time points. FcγRI mRNA expression was significantly lower, and FcγRII and FcγRIII were higher, in p47phox-/- mice than in controls. NADPH-oxidase-driven oxygen radical production determines chondrocyte death and aggravates MMP-mediated
cartilage destruction during IFN-γ-stimulated IC-mediated arthritis. Upregulation of FcγRI by oxygen radicals may contribute
to cartilage destruction. 相似文献
270.
Arjen?MeijerEmail author Mark?HuijbregtsEmail author Lucas?Reijnders 《The International Journal of Life Cycle Assessment》2005,10(5):309-316
- Part 1: Characterisation factors (DOI: http://dx.doi.org/10.1065/lca2004.12.194.1)
Part 2: Damage scores (DOI: http://dx.doi.org/10.1065/lca2004.12.194.2)
- Preamble. In this series of two papers, a methodology to calculate damages to human health caused by indoor emissions from
building materials is presented and applied. Part 1 presents the theoretical foundation of the indoor emission methodology
developed, as well as characterisation factors calculated for 36 organic compounds, radon and gamma radiation. Part 2 calculates
damage scores of building materials with the characterisation factors presented in part 1. The relevancy of including indoor
air emission in the full damage scores at a material level and a dwelling level is also quantified and discussed.
Goal, Scope and Background Methodologies based on life cycle assessment have been developed to calculate the environmental impact of dwellings. Human
health damage due to exposure to substances emitted to indoor air are not included in these methodologies. In order to compare
this damage with human health damages associated with the rest of the life cycle of the dwelling, a methodology has been developed
to calculate damages to human health caused by pollutants emitted from building materials.
Methods Fate, exposure and health effects are addressed in the calculation procedure. The methodology is suitable for organic substances,
radon and elements emitting gamma radiation. The (Dutch reference) dwelling used in the calculation was divided in three compartments:
crawl space, first floor and second floor. Fate factors have been calculated based on indoor and outdoor intake fractions,
dose conversion factors or extrapolation from measurements. Effect factors have been calculated based on unit risk factors,
(extrapolated) effect doses or linear relationship between dose and cancer cases. Damage factors are based on disability adjusted
life years (DALYs).
Results and Discussion Characterisation factors have been calculated for 36 organic compounds, radon and gamma radiation emitted by building materials
applied in a Dutch reference dwelling. For organic compounds and radon, the characterisation factors of emissions to the second
floor are 10–20% higher than the characterisation factors of emissions to the first floor. For the first and second floor,
the characterisation factors are dominated by damage to human health as a result of indoor exposure. The relative contribution
of carcinogenic and non-carcinogenic effects to the characterisation factors is generally within one order of magnitude, and
up to three orders of magnitude for formaldehyde.
Conclusion Health effects due to indoor exposure to pollutants emitted from building materials appear to be dominant in the characterisation
factors over outdoor exposure to such pollutants. The health effects of emissions of organic compounds and gamma radiation
in the crawl space are very small compared to the health effects of emissions into the other compartments. Using the characterisation
factors calculated in this study, it is possible to calculate the human health damage due to emissions of substances and radiation
emitted to indoor air and compare this damage with damages to human health associated with the rest of the life cycle of the
material. This is the subject of part II of this research. 相似文献