Cadmium uptake by crops from the subsoil

Plant roots penetrate into the subsoil from which they may take up heavy metals, resulting in accumulation in the plant. The subsoil may contain heavy metals, possibly as a result of ploughing down contaminated topsoil. This is why the effect of Cd in the subsoil on Cd plant uptake was studied in outdoor miniplots in eight consecutive years. Cd (as Cd(NO3)2.4H2O) was added to four different layers of two soils (a sand and a sandy loam) at the start of the experiment. Nine arable and vegetable crops were grown and analysed for Cd. For most investigated crops Cd uptake increased linearly with increasing depth of Cd addition to the soils and for some crops (spinach and potato) the increase was exponential (decreasing increase). Cd uptake by crops on sand was higher than on sandy loam. As most investigated crops accumulated Cd from the subsoil, ploughing down a Cd-contaminated topsoil into the subsoil is a risk for the safe production of food and feed crops. It is concluded that acceptable Cd concentration levels in soils should not only be based an the Cd concentration in the topsoil but also on that in the rooted subsoil.     

On the importance of trait interrelationships for understanding environmental responses of stream macroinvertebrates

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Methanobacterium formicicum,an endosymbiont of the anaerobic ciliateMetopus striatus McMurrich

The Gram-positive methanogenic endosymbiont of the sapropelic ciliateMetopus striatus was isolated and identified asMethanobacterium formicicum. In the ciliate cell the methanogens are in close association with microbody-like organelles. No mitochondria could be detected. The nature of the microbodies and the physiological background of the observed association are discussed.     

Bioethics: An Export Product? Reflections on Hands-On Involvement in Exploring the “External” Validity of International Bioethical Declarations

As the technosciences, including genomics, develop into a global phenomenon, the question inevitably emerges whether and to what extent bioethics can and should become a globalised phenomenon as well. Could we somehow articulate a set of core principles or values that ought to be respected worldwide and that could serve as a universal guide or blueprint for bioethical regulations for embedding biotechnologies in various countries? This article considers one universal declaration, the UNESCO Declaration on Bioethics and Human Rights (2005a). General criticisms made in a recent special issue of Developing World Bioethics are that the concepts used in the Declaration are too general and vague to generate real commitment; that the so-called universal values are not universal; and, that UNESCO should not be engaged in producing such declarations which are the domain of professional bioethicists. This article considers these and other criticisms in detail and presents an example of an event in which the Declaration was used: the request by the Republic of Sakha, in Siberia, for a UNESCO delegation to advise on the initiation of a bioethics programme. The Declaration was intended to provide an adequate “framework of principles and procedures to guide states in the formulation of their legislation, policies and other instruments in the field of bioethics” (article 2a). The Declaration was produced, and principles agreed upon, in an interactive and deliberative manner with world-wide expert participation. We argue that the key issue is not whether the general principles can be exported worldwide (in principle they can), but rather how processes of implementation and institutionalisation should take shape in different social and cultural contexts. In particular, broader publics are not routinely involved in bioethical debate and policy-making processes worldwide.     

Cholesterol sensor ORP1L contacts the ER protein VAP to control Rab7–RILP–p150Glued and late endosome positioning

Late endosomes (LEs) have characteristic intracellular distributions determined by their interactions with various motor proteins. Motor proteins associated to the dynactin subunit p150^Glued bind to LEs via the Rab7 effector Rab7-interacting lysosomal protein (RILP) in association with the oxysterol-binding protein ORP1L. We found that cholesterol levels in LEs are sensed by ORP1L and are lower in peripheral vesicles. Under low cholesterol conditions, ORP1L conformation induces the formation of endoplasmic reticulum (ER)–LE membrane contact sites. At these sites, the ER protein VAP (VAMP [vesicle-associated membrane protein]-associated ER protein) can interact in trans with the Rab7–RILP complex to remove p150^Glued and associated motors. LEs then move to the microtubule plus end. Under high cholesterol conditions, as in Niemann-Pick type C disease, this process is prevented, and LEs accumulate at the microtubule minus end as the result of dynein motor activity. These data explain how the ER and cholesterol control the association of LEs with motor proteins and their positioning in cells.     

Indications for an early invasive strategy in NSTE-ACS patients

An early invasive strategy in patients who have acute coronary syndrome without ST-elevation (NSTE-ACS) can improve clinical outcome in high-risk subgroups. According to the current guidelines of the European Society of Cardiology (ESC), the majority of NSTE-ACS patients are classified as “high-risk”. We propose to prioritise patients with a global registry of acute coronary events (GRACE) risk score >140 over patients with isolated troponin rise or electrocardiographic changes and a GRACE risk score <140. We also acknowledge that same-day transfer for all patients at a high risk is not necessary in the Netherlands since the majority of Dutch cardiology departments are equipped with a catheterisation laboratory where diagnostic coronary angiography is routinely performed in NSTE-ACS patients. Therefore, same-day transfer should be restricted to true high-risk patients (in addition to those NSTE-ACS patients with very high-risk (VHR) criteria) in centres without coronary angiography capabilities.

     

Within-Host Spatiotemporal Dynamics of Plant Virus Infection at the Cellular Level

A multicellular organism is not a monolayer of cells in a flask; it is a complex, spatially structured environment, offering both challenges and opportunities for viruses to thrive. Whereas virus infection dynamics at the host and within-cell levels have been documented, the intermediate between-cell level remains poorly understood. Here, we used flow cytometry to measure the infection status of thousands of individual cells in virus-infected plants. This approach allowed us to determine accurately the number of cells infected by two virus variants in the same host, over space and time as the virus colonizes the host. We found a low overall frequency of cellular infection (<0.3), and few cells were coinfected by both virus variants (<0.1). We then estimated the cellular contagion rate (R), the number of secondary infections per infected cell per day. R ranged from 2.43 to values not significantly different from zero, and generally decreased over time. Estimates of the cellular multiplicity of infection (MOI), the number of virions infecting a cell, were low (<1.5). Variance of virus-genotype frequencies increased strongly from leaf to cell levels, in agreement with a low MOI. Finally, there were leaf-dependent differences in the ease with which a leaf could be colonized, and the number of virions effectively colonizing a leaf. The modeling of infection patterns suggests that the aggregation of virus-infected cells plays a key role in limiting spread; matching the observation that cell-to-cell movement of plant viruses can result in patches of infection. Our results show that virus expansion at the between-cell level is restricted, probably due to the host environment and virus infection itself.