The trimeric organisation of photosystem I is not necessary for the iron-stress induced CP43′ protein to functionally associate with this reaction centre

AbstractA mutant of Synechocystis PCC 6803 lacking the PsaL subunit of photosystem I (PSI) has been grown in iron-deficient media to induce the expression of the isiA gene, which encodes the chlorophyll a-binding protein CP43′. The purpose of this was to establish whether or not the formation of an 18-mer CP43′-PSI supercomplex reported for wild type Synechocystis cells [Nature 412 (2001) 743–745] was dependent on the trimeric conformation of the cyanobacterial PSI reaction centre. Structural characterisation by electron microscopy and single particle image analysis has revealed that the PsaL-mutant does not form trimers of PSI. However, despite this, CP43′ was found to associate with the PSI monomer. The PSI monomer bound six or seven copies of CP43′ along one edge of the PSI monomer and can be compared with one segment of the trimeric 18-mer CP43′-PSI supercomplex. We therefore conclude that the trimeric nature of cyanobacterial PSI is not required for the assembly of the CP43′ antenna system under iron-deficient conditions

Climate Variability and the Millennium Development Goal Hunger Target

Climate variability contributes significantly to poverty and food insecurity. Proactive approaches to managing climate variability within vulnerable rural communities and among institutions operating at community, sub-national, and national levels is a crucial step toward achieving the Millennium Development Goal of eradicating extreme poverty and hunger. Climate variability can impact a household's access to food by affecting subsistence production, income from primary production, local food prices, and sometimes the economy of an entire region. The risk of household food insecurity is determined by the success of livelihood strategies in the face of climate and other shocks. Across the economy, climate variability affects food security through its influence on investment, adoption of agricultural technology, aggregate production, market prices and economic development, and hence the ability of individuals, communities and nations to produce and purchase food. The impacts of climate variability are both ex post – losses that follow a climate shock — and ex ante — opportunity costs of conservative risk management responses to climatic uncertainty. The report summarizes the scientific basis, current methodology, and prospects for improving climate prediction at a seasonal time scale. Current forecast methods give modest to moderately-high prediction skill in "hunger hotspots" in East, West and Southern Africa, and other regions in the tropics and subtropics. Applications of climate information contribute to a comprehensive strategy to combat hunger. First is the use of seasonal climate prediction in early warning systems to guide interventions to avert food crises. Second is the use of climate information to manage risk in agricultural systems within vulnerable rural communities and among a range of institutions. This includes smallholder farmers who comprise the largest group of poor and food-insecure; intermediary institutions that interface with farmers, and can provide the information, technical guidance and production inputs required for effective climate risk management; and institutions that make climate-sensitive decisions at a broader scale that influence food security. We also discuss measures to strengthen institutional capacity and coordination to improve management of climate variability. Improved management of climate variability has appealing synergies with other interventions that target hunger, including soil fertility management, small-scale water management, markets, and extension and communication systems

A Single Tri-Epitopic Antibody Virtually Recapitulates the Potency of a Combination of Three Monoclonal Antibodies in Neutralization of Botulinum Neurotoxin Serotype A.

The standard of treatment for botulism, equine antitoxin, is a foreign protein with associated safety issues and a short serum half-life which excludes its use as a prophylactic antitoxin and makes it a less-than-optimal therapeutic. Due to these limitations, a recombinant monoclonal antibody (mAb) product is preferable. It has been shown that combining three mAbs that bind non-overlapping epitopes leads to highly potent botulinum neurotoxin (BoNT) neutralization. Recently, a triple human antibody combination for BoNT/A has demonstrated potent toxin neutralization in mouse models with no serious adverse events when tested in a Phase I clinical trial. However, a triple antibody therapeutic poses unique development and manufacturing challenges. Thus, potentially to streamline development of BoNT antitoxins, we sought to achieve the potency of multiple mAb combinations in a single IgG-based molecule that has a long serum half-life. The design, production, and testing of a single tri-epitopic IgG1-based mAb (TeAb) containing the binding sites of each of the three parental BoNT/A mAbs yielded an antibody of nearly equal potency to the combination. The approach taken here could be applied to the design and creation of other multivalent antibodies that could be used for a variety of applications, including toxin elimination

Assessing the Reliability and Credibility of Industry Science and Scientists

The chemical industry extensively researches and tests its products to implement product stewardship commitments and to ensure compliance with governmental requirements. In this commentary we argue that a wide variety of mechanisms enable policymakers and the public to assure themselves that studies performed or funded by industry are identified as such, meet high scientific standards, and are not suppressed when their findings are adverse to industry’s interests. The more a given study follows these practices and standards, the more confidence one can place in it. No federal laws, rules, or policies express a presumption that scientific work should be ignored or given lesser weight because of the source of its funding. To the contrary, Congress has consistently mandated that agencies allow interested or affected parties to provide information to them and fairly consider that information. All participants in scientific review panels should disclose sources of potential biases and conflicts of interest. The former should be considered in seeking a balanced panel rather than being used as a basis for disqualification. Conflicts of interest generally do require disqualification, except where outweighed by the need for a person’s services. Within these constraints, chemical industry scientists can serve important and legitimate functions on scientific advisory panels and should not be unjustifiably prevented from contributing to their work

Observation of an oxygen isotope effect in YBa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e7\u3c/sub\u3e

A small decrease in Tc of 0.3 K to 0.5 K is observed when as much as 90% of the 16O in YBa2Cu3O7 is substituted with18O. This result is consistent with our observation that there is an oxygen isotope effect in La1.85Sr0.15CuO4, but in contrast with previous reports that there is no isotope effect for YBa2Cu3O7. This new result suggests that phonons play an important role in the electron-pairing mechanism in YBa2Cu3O7