Xanthorhodopsin: a proton pump with a light-harvesting carotenoid antenna

Energy transfer from light-harvesting carotenoids to chlorophyll is common in photosynthesis, but such antenna pigments have not been observed in retinal-based ion pumps and photoreceptors. Here we describe xanthorhodopsin, a proton-pumping retinal protein/carotenoid complex in the eubacterium Salinibacter ruber. The wavelength dependence of the rate of pumping and difference absorption spectra measured under a variety of conditions indicate that this protein contains two chromophores, retinal and the carotenoid salinixanthin, in a molar ratio of about 1:1. The two chromophores interact strongly, and light energy absorbed by the carotenoid is transferred to the retinal with a quantum efficiency of approximately 40%. The antenna carotenoid extends the wavelength range of the collection of light for uphill transmembrane proton transport.     

Risk factors for stillbirth and foetal mummification in four Brazilian swine herds

The objective of this study was to identify the risk factors of stillbirth and foetal mummification in 565 farrowings of four commercial pig farms in Brazil. Stillborn piglets were observed in 31.3% of the litters and the stillborn risk was 5.6%. Mummified foetuses occurred in 42.1% of the litters and the mummification risk was 3.4%. The potential risk factors were included in multivariable logistic regression models as categories: herd (1–4); parity (1, 2–5 and >5); litter size (<10, 10–12 and >12 piglets); farrowing length (≤3 or >3 h); presence of mummified foetuses (yes or no); farrowing induction (yes or no); use of oxytocin (yes or no); use of vaginal palpation (yes or no); body condition score (<3, 3 and ≥4), and placental production index (PPI) (≤5 or >5) which was measured as the ratio of total foetal weight to total placental weight. Duration of farrowing and use of farrowing induction, oxytocin or vaginal palpation were not included in the model that investigated the risk factors of foetal mummification. Two models were used to investigate the risk factors of stillbirth, one with and the other without the inclusion of farrowing length. When compared to sows of parity 2–5, sows of parity >5 had 1.7- and 1.6-times higher odds (P < 0.05) for stillbirth in the models with and without the inclusion of farrowing length, respectively. In both models, sows with more than 12 piglets/litter had 3.6-times higher odds of stillbirth occurrence compared to sows with less than 10 piglets (P < 0.05). Sows with prolonged farrowing (>3 h) had 2.0-times higher odds of stillbirth occurrence than sows with short farrowing (P < 0.05). Sows with more than 12 piglets/litter had 14.5-times higher odds of mummification compared to sows with less than 10 piglets (P < 0.05). Sows of parities 1 and >5 had 3.5- and 2.0-times, respectively, higher odds of mummification in comparison to sows of parity 2–5 (P < 0.05). Sows with low PPI had 1.7-times higher odds of mummification compared to those with high PPI (P < 0.05). A large litter, a high-parity and a prolonged farrowing increased the risk of stillbirth. The probability of having a mummified foetus was increased in very young and older sows, when having a large litter and a litter with a less efficient placenta.     

Concentrations of cartilage oligomeric matrix protein in dogs with naturally developing and experimentally induced arthropathy

OBJECTIVE: To assay concentrations of cartilage oligomeric matrix protein (COMP) in canine sera and synovial fluid (SF), to compare COMP concentrations in clinically normal dogs and dogs with joint disease, and to analyze changes in COMP concentrations in dogs with experimentally induced acute synovitis. ANIMALS: 69 control dogs without joint disease, 23 dogs with naturally occurring aseptic arthropathy, and 6 dogs with experimentally induced synovitis. PROCEDURE: Serum (n = 69) and SF (36) were obtained from control dogs. Samples of serum (n = 23) and SF (13) were obtained from dogs with naturally occurring aseptic arthropathy with or without radiographic features of osteoarthritis (OA). Serum and SF were obtained before and 1, 2, 3, and 7 days after induction of synovitis. The COMP concentrations were determined by use of an inhibition ELISA that had canine cartilage COMP and monoclonal antibody against human COMP. RESULTS: Concentrations of COMP in serum and SF of control dogs were 31.3+/-15.3 and 298.7+/-124.7 microg/ml, respectively. In naturally occurring OA, COMP concentrations in serum (44.9+/-177 microg/ml) and SF (401.7+/-74.3 microg/ml) were significantly higher than corresponding concentrations in control dogs. The COMP concentration in SF peaked 24 and 48 hours after induction of synovitis, whereas concentration in serum peaked on day 3. CONCLUSIONS AND CLINICAL RELEVANCE: These results supported the hypothesis that COMP concentration in serum and SF of dogs may be altered after cartilage degradation or synovitis. Measurement of COMP concentrations can be useful when differentiating arthropathies in dogs.     

Chloroplast biogenesis 91: Detection of δ-aminolevulinic acid esterases activity in higher plant and insect tissues

δ-Aminolevulinic acid (ALA) esterase(s) is an enzyme or a family of enzymes that regenerate ALA from ALA esters by hydrolysis. These enzyme(s) are highly active in cancer cells. As a consequence ALA esters have been used to advantage in ALA-dependent photoradiation therapy, since ALA esters translocate better to sites of metabolism in cancer cells and tissues than free ALA. In this work, it is shown that ALA esterase(s) also occur in insect and plant tissues, but are less active than in cancer cells. In plant cells ALA esterase activity is observed in the cytosol as well as in the plastids where most of the activity is observed in the plastid stoma. The ALA esterase activity appears to be sensitive to the nature of the esterifying alcohol as well as to components of the incubation medium. The observed lower activity of ALA ester conversion to tetrapyrroles in insect and plant cells, in comparison to free ALA, suggests that the use of ALA esters in photodynamic insecticidal and herbicidal applications may not be as advantageous as their use in cancer photodynamic therapy treatments. It is proposed that ALA esterase(s) may be involved in the mobilization of sequestered and esterified ALA. Esterification and sequestering of excess ALA may be visualized as a mean of cellular detoxification.     

Evaluation of genetic diversity of sweet potato [Ipomoea batatas (L.) Lam.] on different ploidy levels applying two capillary platforms

The genetic composition of sweet potato [Ipomoea batatas (L.) Lam.] (2n = 6x = 90) is reflected in different levels of genetic variation. The main objective of the present study was a comparison of genetic diversity parameters of different ploidy levels (2n, 4n, and 6n codominant allele determination), analyzed on two high-resolution capillary platforms. Fragment analysis was performed by applying SSR markers on a 3130XL Genetic Analyzer (ABI 3130) and QIAxcel Advanced System (QX). A high level of expected heterozygosity (He) as a measure of genetic diversity was observed for both ABI3130 (0.731) and QX (0.679). Molecular variance was 17% for ABI3130 and 10% for QX. Comparison between genetic distance matrices based on allele lengths showed a moderate Mantel correlation coefficient (rxy = 0.557) between ABI3130 and QX. Global cluster analysis using the Bayesian approach distributed the observed genotypes into two clusters on both capillary platforms. Our results show that the two high-resolution capillary electrophoreses for codominant data on 2n, 4n, and 6n levels are applicable in genetic diversity studies but their efficiency depends on in-resolution expectations, financial resources, available time, and the equipment of the laboratory.     

Efficacy and Mechanism of Action of Marine Alkaloid 3,10-Dibromofascaplysin in Drug-Resistant Prostate Cancer Cells

Efficacy and mechanism of action of marine alkaloid 3,10-dibromofascaplysin (DBF) were investigated in human prostate cancer (PCa) cells harboring different levels of drug resistance. Anticancer activity was observed across all cell lines examined without signs of cross-resistance to androgen receptor targeting agents (ARTA) or taxane based chemotherapy. Kinome analysis followed by functional investigation identified JNK1/2 to be one of the molecular targets of DBF in 22Rv1 cells. In contrast, no activation of p38 and ERK1/2 MAPKs was observed. Inhibition of the drug-induced JNK1/2 activation or of the basal p38 activity resulted in increased cytotoxicity of DBF, whereas an active ERK1/2 was identified to be important for anticancer activity of the alkaloid. Synergistic effects of DBF were observed in combination with PARP-inhibitor olaparib most likely due to the induction of ROS production by the marine alkaloid. In addition, DBF intensified effects of platinum-based drugs cisplatin and carboplatin, and taxane derivatives docetaxel and cabazitaxel. Finally, DBF inhibited AR-signaling and resensitized AR-V7-positive 22Rv1 prostate cancer cells to enzalutamide, presumably due to AR-V7 down-regulation. These findings propose DBF to be a promising novel drug candidate for the treatment of human PCa regardless of resistance to standard therapy.     

The focusing of electron flow and a Veselago lens in graphene p-n junctions

The focusing of electric current by a single p-n junction in graphene is theoretically predicted. Precise focusing may be achieved by fine-tuning the densities of carriers on the n- and p-sides of the junction to equal values. This finding may be useful for the engineering of electronic lenses and focused beam splitters using gate-controlled n-p-n junctions in graphene-based transistors.     

Kinesin and dynein move a peroxisome in vivo: a tug-of-war or coordinated movement?

We used fluorescence imaging with one nanometer accuracy (FIONA) to analyze organelle movement by conventional kinesin and cytoplasmic dynein in a cell. We located a green fluorescence protein (GFP)-tagged peroxisome in cultured Drosophila S2 cells to within 1.5 nanometers in 1.1 milliseconds, a 400-fold improvement in temporal resolution, sufficient to determine the average step size to be approximately 8 nanometers for both dynein and kinesin. Furthermore, we found that dynein and kinesin do not work against each other in vivo during peroxisome transport. Rather, multiple kinesins or multiple dyneins work together, producing up to 10 times the in vitro speed.     

The Chlamydomonas genome reveals the evolution of key animal and plant functions

Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.