Emerging facets of plastid division regulation

Plastids are complex organelles that are integrated into the plant host cell where they differentiate and divide in tune with plant differentiation and development. In line with their prokaryotic origin, plastid division involves both evolutionary conserved proteins and proteins of eukaryotic origin where the host has acquired control over the process. The plastid division apparatus is spatially separated between the stromal and the cytosolic space but where clear coordination mechanisms exist between the two machineries. Our knowledge of the plastid division process has increased dramatically during the past decade and recent findings have not only shed light on plastid division enzymology and the formation of plastid division complexes but also on the integration of the division process into a multicellular context. This review summarises our current knowledge of plastid division with an emphasis on biochemical features, the functional assembly of protein complexes and regulatory features of the overall process.     

Parkinson Disease Protein DJ-1 Binds Metals and Protects against Metal-induced Cytotoxicity

The progressive loss of motor control due to reduction of dopamine-producing neurons in the substantia nigra pars compacta and decreased striatal dopamine levels are the classically described features of Parkinson disease (PD). Neuronal damage also progresses to other regions of the brain, and additional non-motor dysfunctions are common. Accumulation of environmental toxins, such as pesticides and metals, are suggested risk factors for the development of typical late onset PD, although genetic factors seem to be substantial in early onset cases. Mutations of DJ-1 are known to cause a form of recessive early onset Parkinson disease, highlighting an important functional role for DJ-1 in early disease prevention. This study identifies human DJ-1 as a metal-binding protein able to evidently bind copper as well as toxic mercury ions in vitro. The study further characterizes the cytoprotective function of DJ-1 and PD-mutated variants of DJ-1 with respect to induced metal cytotoxicity. The results show that expression of DJ-1 enhances the cells'' protective mechanisms against induced metal toxicity and that this protection is lost for DJ-1 PD mutations A104T and D149A. The study also shows that oxidation site-mutated DJ-1 C106A retains its ability to protect cells. We also show that concomitant addition of dopamine exposure sensitizes cells to metal-induced cytotoxicity. We also confirm that redox-active dopamine adducts enhance metal-catalyzed oxidation of intracellular proteins in vivo by use of live cell imaging of redox-sensitive S3roGFP. The study indicates that even a small genetic alteration can sensitize cells to metal-induced cell death, a finding that may revive the interest in exogenous factors in the etiology of PD.     

Fisheries Certification in Russia: The Emergence of Nonstate Authority in a Postcommunist Economy

Market-based incentives are a new approach to direct fisheries toward greater sustainability. The Marine Stewardship Council (MSC) is the leading certification scheme for wild capture fisheries. Four Russian fisheries were certified from 2010 to 2014. Despite a slow start, the Russian fishery assessments have gone more quickly, received less public criticism, and scored better over time. Consensus is emerging that the Russian system for fisheries management fulfills the MSC requirements.     

Three dimensional patient-specific collagen architecture modulates cartilage responses in the knee joint during gait

Site-specific variation of collagen fibril orientations can affect cartilage stresses in knee joints. However, this has not been confirmed by 3-D analyses. Therefore, we present a novel method for evaluation of the effect of patient-specific collagen architecture on time-dependent mechanical responses of knee joint cartilage during gait. 3-D finite element (FE) models of a human knee joint were created with the collagen architectures obtained from T₂ mapped MRI (patient-specific model) and from literature (literature model). The effect of accuracy of the implementation of collagen fibril architecture into the model was examined by using a submodel with denser FE mesh. Compared to the literature model, fibril strains and maximum principal stresses were reduced especially in the superficial/middle regions of medial tibial cartilage in the patient-specific model after the loading response of gait (up to ?413 and ?26%, respectively). Compared to the more coarsely meshed joint model, the patient-specific submodel demonstrated similar strain and stress distributions but increased values particularly in the superficial cartilage regions (especially stresses increased >60%). The results demonstrate that implementation of subject-specific collagen architecture of cartilage in 3-D modulates location- and time-dependent mechanical responses of human knee joint cartilage. Submodeling with more accurate implementation of collagen fibril architecture alters cartilage stresses particularly in the superficial/middle tissue.     

Strong Interplay between Sodium and Oxygen in Kesterite Absorbers: Complex Formation,Incorporation, and Tailoring Depth Distributions

Sodium and oxygen are prevalent impurities in kesterite solar cells. Both elements are known to strongly impact performance of the kesterite devices and can be connected to efficiency improvements seen after heat treatments. The sodium distribution in the kesterite absorber is commonly reported, whereas the oxygen distribution has received less attention. Here, a direct relationship between sodium and oxygen in kesterite absorbers is established using secondary ion mass spectrometry and explained by defect analyses within the density functional theory. The calculations reveal a binding energy of 0.76 eV between the substitutional defects Na_Cu and O_S in the nearest neighbor configuration, indicating an abundance of Na? O complexes in kesterite absorbers at relevant temperatures. Oxygen incorporation is studied by introducing isotopic ¹⁸O at different stages of the Cu₂ZnSnS₄/Mo/soda‐lime glass baseline processing. It is observed that oxygen from the Mo back contact and contaminations during the sulfurization are primary contributors to the oxygen distribution. Indeed, unintentional oxygen incorporation leads to immobilization of sodium. This results in a strong correlation between sodium and oxygen, in excellent agreement with the theoretical calculations. Consequently, oxygen availability should be monitored to optimize postdeposition heat treatments to control impurities in kesterite absorbers and ultimately, the solar cell efficiency.     

Alpha1-AR-mediated activation of NKCC in rat cardiomyocytes involves ERK-dependent phosphorylation of the cotransporter

We studied molecular and functional characteristics as well as hormonal regulation of the Na-K-2Cl cotransporter (NKCC) in the isolated rat heart and cardiomyocytes. NKCC activity was measured as bumetanide-sensitive (86)Rb(+) influx in isolated perfused rat hearts and isolated cardiomyocytes. Stimulation of alpha(1)-adrenoceptors (AR) by phenylephrine (30 microM) increased (86)Rb(+) influx. The NKCC inhibitor bumetanide (50 microM) reduced the response to phenylephrine by 45 +/- 13% (n = 12, P < 0.01). PD-98059 (10 microM), an inhibitor of the activation of the mitogen-activated protein kinases extracellular signal-regulated protein kinase 1 and 2 (ERK1/2), reduced the total response to phenylephrine by 51 +/- 13% (n = 10, P < 0.01) and eliminated the bumetanide-sensitive component, indicating that alpha(1)-AR mediated stimulation of NKCC is dependent on activation of ERK1/2. Inhibitors of protein kinase C or phosphatidylinositol 3-kinase had no effect. The presence of NKCC mRNA and protein was demonstrated in isolated rat cardiomyocytes. Phosphorylation of NKCC after alpha(1)-AR stimulation was shown by immunoprecipitation of the phosphoprotein from (32)P(i) prelabeled cardiomyocytes. Increased phosphorylation of the NKCC protein was also abolished by PD-98059. We conclude that the NKCC is present in rat cardiomyocytes and that ion transport by the cotransporter is regulated by alpha(1)-AR stimulation through phosphorylation of this protein involving the ERK pathway.     

Effects of climate on incidence of Campylobacter spp. in humans and prevalence in broiler flocks in Denmark

Campylobacter infections are increasing and pose a serious public health problem in Denmark. Infections in humans and broiler flocks show similar seasonality, suggesting that climate may play a role in infection. We examined the effects of temperature, precipitation, relative humidity, and hours of sunlight on Campylobacter incidence in humans and broiler flocks by using lag dependence functions, locally fitted linear models, and cross validation methods. For humans, the best model included average temperature and sunlight 4 weeks prior to infection; the maximum temperature lagged at 4 weeks was the best single predictor. For broilers, the average and maximum temperatures 3 weeks prior to slaughter gave the best estimate; the average temperature lagged at 3 weeks was the best single predictor. The combined effects of temperature and sunlight or the combined effects of temperature and relative humidity predicted the incidence in humans equally well. For broiler flock incidence these factors explained considerably less. Future research should focus on elements within the broiler environment that may be affected by climate, as well as the interaction of microclimatic factors on and around broiler farms. There is a need to quantify the contribution of broilers as a source of campylobacteriosis in humans and to further examine the effect of temperature on human incidence after this contribution is accounted for. Investigations should be conducted into food consumption and preparation practices and poultry sales that may vary by season.