A potential molecular mechanism for hypersensitivity caused by formalin-inactivated vaccines

Heat, oxidation and exposure to aldehydes create reactive carbonyl groups on proteins, targeting antigens to scavenger receptors. Formaldehyde is widely used in making vaccines, but has been associated with atypical enhanced disease during subsequent infection with paramyxoviruses. We show that carbonyl groups on formaldehyde-treated vaccine antigens boost T helper type 2 (T(H)2) responses and enhance respiratory syncytial virus (RSV) disease in mice, an effect partially reversible by chemical reduction of carbonyl groups.     

Fruit-specific expression of the A. tumefaciens isopentenyl transferase gene in tomato: effects on fruit ripening and defense-related gene expression in leaves

This paper describes the analysis of tomato plants transformed with a chimeric gene consisting of the promoter region of a fruit specifically expressed tomato gene linked to the ipt gene coding sequences from the Ti plasmid of Agrobacterium tumefaciens. The pattern of expression of this chimeric gene was found to be consistent with the expression of the endogenous fruit-specific gene and consequently, plants expressing the chimeric gene were phenotypically normal until fruit maturation and ripening. A dramatically altered fruit phenotype, islands of green pericarp tissue remaining on otherwise deep red ripe fruit, was then evident in many of the transformed plants. Cytokinin levels in transformed plant fruit tissues were 10 to 100-fold higher than in control fruit. In the leaves of a fruit-bearing transformant, despite a lack of detectable ipt mRNA accumulation, approximately fourfold higher than control leaf levels of cytokinin were detected. It is suggested that cytokinin produced in fruit is being transported to the leaves since accumulation in leaves of PR-1 and chitinase mRNAs, which encode defense-related proteins known to be induced by cytokinin, occurred only when the transformant was reproductively active. Effects of elevated cytokinin levels on tomato fruit gene expression and cellular differentiation processes are also described.     

The impacts of invasive ecosystem engineers in freshwaters: A review

1. Invasive species are a key stressor in freshwater ecosystems. When these species are also ecosystem engineers, their impacts are exacerbated because they modulate resource availability for a wide range of other species. The aim of this review is to synthesise existing knowledge of the impacts of invasive ecosystem engineers in freshwaters and identify knowledge gaps requiring further research.
2. The four questions explored in this review are: (1) What are the trends in research into invasive ecosystem engineers? (2) What are common negative effects of invasive ecosystem engineers in freshwater? (3) Do all impacts of invasive ecosystem engineers have negative consequences for biodiversity? (4) What happens when multiple ecosystem engineers interact? Four literature searches in Web of Science have been used to identify articles for the review and to estimate relative research effort between terrestrial, marine and freshwater ecosystems.
3. The number of research articles focusing on ecosystem engineers across all ecosystem types is increasing. Despite well-known examples of ecosystem engineer species in freshwaters (e.g. beaver), more research has focussed on terrestrial environments and invasive species.
4. The effects of invasive ecosystem engineers in freshwater systems are varied and often context dependent. Their effects on biodiversity or native ecosystem engineers are often shown to be negative; however, not all effects associated with these species are deleterious to native species. For instance, some invasive ecosystem engineers support native species through the provision of food or refuges.
5. Although freshwater ecosystems are often influenced by multiple species of ecosystem engineers (including native, invasive or both), little is known about interactions between these species or the combined effects of multiple ecosystem engineers. More research is also needed that relates the results of laboratory experiments to the field and develops methods for measuring factors that govern the impact of engineers on ecosystems. Understanding the spatial variability of the impacts of invasive ecosystem engineers as well as their interaction with anthropogenic stressors (e.g. hydrologic modification) is also necessary.
6. The lag in research surrounding invasive ecosystem engineers in freshwater compared to other biomes is concerning, as freshwater ecosystems support biodiversity disproportionate to the area they occupy. Creating predictive models of the impacts of freshwater ecosystem engineers would help anticipate the effects of invasive ecosystem engineers in freshwater and add to the broader understanding of their effects in other biomes.

     

Distinct properties and functions of CTCF revealed by a rapidly inducible degron system

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Acclimation of the respiration/photosynthesis ratio to temperature: insights from a model

Based on short-term experiments, many plant growth models – including those used in global change research – assume that an increase in temperature stimulates plant respiration (R) more than photosynthesis (P), leading to an increase in the R/P ratio. Longer-term experiments, however, have demonstrated that R/P is relatively insensitive to growth temperature. We show that both types of temperature response may be reconciled within a simple substrate-based model of plant acclimation to temperature, in which respiration is effectively limited by the supply of carbohydrates fixed through photosynthesis. The short-term, positive temperature response of R/P reflects the transient dynamics of the nonstructural carbohydrate and protein pools; the insensitivity of R/P to temperature on longer time-scales reflects the steady-state behaviour of these pools. Thus the substrate approach may provide a basis for predicting plant respiration responses to temperature that is more robust than the current modelling paradigm based on the extrapolation of results from short-term experiments. The present model predicts that the acclimated R/P depends mainly on the internal allocation of carbohydrates to protein synthesis, a better understanding of which is therefore required to underpin the wider use of a constant R/P as an alternative modelling paradigm in global change research.