Natural variation in the promoter of OsHMA3 contributes to differential grain cadmium accumulation between Indica and Japonica rice

Rice is a major source of cadmium(Cd) intake for Asian people. Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, underlying genetic bases for differential Cd accumulation between Indica and Japonica rice are still unknown. In this study, we cloned a quantitative trait locus(QTL) grain Cd concentration on chromosome 7(GCC7) responsible for differential grain Cd accumulation between two rice varieties by performing QTL analysis and map-based cloning. We found that the two GCC7 alleles, GCC7~(PA64s) and GCC7~(93-11), had different promoter activity of OsHMA3,leading to different OsHMA3 expression and different shoot and grain Cd concentrations. By analyzing the distribution of different haplotypes of GCC7 among diverse rice accessions, we discovered that the high and low Cd accumulation alleles, namely GCC7~(93-11) and GCC7~(PA64s), were preferentially distributed in Indica and Japonica rice,respectively. We further showed that the GCC7~(PA64s)allele can be used to replace the GCC7~(93-11) allele in the super cultivar 93-11 to reduce grain Cd concentration without adverse effect on agronomic traits. Our results thus reveal that the QTL GCC7 with sequence variation in the OsHMA3 promoter is an important determinant controlling differential grain Cd accumulation between Indica and Japonica rice.     

Two intromittent organs in Zorotypus caudelli (Insecta,Zoraptera): the paradoxical coexistence of an extremely long tube and a large spermatophore

Very unusual genitalia of the species Zorotypus caudelli are described. It contains the unique configuration of two different intromittent organs, one of them strongly elongated. Hyper elongated genitalia are known in different groups of insects. Males have to accommodate these unwieldy structures in the limited spaces of the abdomen and manipulate them acutely during copulation. A crucial question is how do species with elongated genitalia cope with these requirements? To investigate this, we studied key features enabling storage, insertion, and withdrawal of the elongated genitalia. The co‐existence of an elongated narrow tube and a bulky spermatophore is a highly unusual and apparently paradoxical condition. However, we demonstrate that the tube is not involved in sperm transmission, whereas the large spermatophore is transferred to females by a membranous fold of the genitalia. The movement of the spermatophore is caused by haemolymph pressure, which likely also promotes the insertion of both intromittent organs. A comparison with the genital anatomy and reproductive mode in related groups suggests that the elongated tube and its accommodating pouch is a de novo structure, and that the ancestral sperm transport via spermatophore is a preadaptive condition for the acquisition of this unusual structure. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 40–54.     

Morphological and quantitative evaluation of the ovarian recrudescence in Nile tilapia (Oreochromis niloticus) after spawning in captivity

The Nile tilapia is one of the most important fish species for aquaculture worldwide. Understanding their reproductive biology is essential for improving their aquaculture methods. The morphological and quantitative dynamics of ovarian recrudescence of Oreochromis niloticus was studied for 21 days postspawning. To accomplish this, breeding females were kept in controlled conditions and ovarian samples were collected weekly for histological, ultrastructural and morphometric analyses. Ovarian follicle morphology revealed an intense synthesis activity of the follicular cells, which actively contributed to formation of the zona radiata and oocyte development following spawning. Recently spawned ovaries contained follicles at all developmental stages, but they were predominantly early primary growth (～42%) and full‐grown follicles (～20%). Remnants of spawning, postovulatory follicle complexes represented approximately 5% of the former ovarian follicles immediately after spawning, and less than 1% after 7 days. Atretic follicles accounted for approximately 2% of the follicles studied during the period. The stock of primary growth follicles was stable during ovarian recrudescence, indicating their availability for continuous recruitment. Only the frequency of full‐grown follicles significantly increased in the ovaries during recrudescence, representing approximately 35% of the follicles 21 days postspawning. The diameters of all follicles were significantly different between the periods analyzed. The ovaries' morphological characteristics, the maintenance of young follicles stocks and the gradual and significant increase in the proportion and diameter of full‐grown follicles showed a rapid ovarian recovery and follicular growth of O. niloticus, in 21 days at 29.5°C, necessary for the next spawning. J. Morphol. 275:348–356, 2014. © 2013 Wiley Periodicals, Inc.     

Jasmonate‐dependent modifications of the pectin matrix during potato development function as a defense mechanism targeted by Dickeya dadantii virulence factors

The plant cell wall constitutes an essential protection barrier against pathogen attack. In addition, cell‐wall disruption leads to accumulation of jasmonates (JAs), which are key signaling molecules for activation of plant inducible defense responses. However, whether JAs in return modulate the cell‐wall composition to reinforce this defensive barrier remains unknown. The enzyme 13–allene oxide synthase (13–AOS) catalyzes the first committed step towards biosynthesis of JAs. In potato (Solanum tuberosum), there are two putative St13–AOS genes, which we show here to be differentially induced upon wounding. We also determine that both genes complement an Arabidopsis aos null mutant, indicating that they encode functional 13–AOS enzymes. Indeed, transgenic potato plants lacking both St13–AOS genes (CoAOS1/2 lines) exhibited a significant reduction of JAs, a concomitant decrease in wound‐responsive gene activation, and an increased severity of soft rot disease symptoms caused by Dickeya dadantii. Intriguingly, a hypovirulent D. dadantii pel strain lacking the five major pectate lyases, which causes limited tissue maceration on wild‐type plants, regained infectivity in CoAOS1/2 plants. In line with this, we found differences in pectin methyl esterase activity and cell‐wall pectin composition between wild‐type and CoAOS1/2 plants. Importantly, wild‐type plants had pectins with a lower degree of methyl esterification, which are the substrates of the pectate lyases mutated in the pel strain. These results suggest that, during development of potato plants, JAs mediate modification of the pectin matrix to form a defensive barrier that is counteracted by pectinolytic virulence factors from D. dadantii.     

Divergent post‐breeding distribution and habitat associations of fledgling and adult Black‐footed Albatrosses Phoebastria nigripes in the North Pacific

Past tracking studies of marine animals have primarily targeted adults, biasing our understanding of at‐sea habitat use toward older life stages. Anthropogenic threats persist throughout the at‐sea ranges of all life stages and it is therefore of interest to population ecologists and managers alike to understand spatiotemporal distributions and possible niche differentiation between age‐classes. In albatrosses, particularly little is known about the juvenile life stage when fledglings depart the colonies and venture to sea with no prior experience or parental guidance. We compared the dispersal of 22 fledgling Black‐footed Albatross Phoebastria nigripes between 2006 and 2008 using satellite telemetry and 16 adults between 2008 and 2009 using geolocaters from Midway Atoll National Wildlife Refuge, Northwest Hawaiian Islands. Following tag deployment, all fledglings spent several days within the calm atoll waters, then travelled northward until reaching 750–900 km from the colony. At this point, fledgling distributions approached the productive North Pacific Transition Zone (NPTZ). Rather than reaching the high chlorophyll a densities on the leading edge of this zone, however, fledglings remained in areas of low productivity in the subtropical gyre. In contrast, adult albatrosses from the same breeding colony did not utilize the NPTZ at this time of year but rather ranged throughout the highly productive northern periphery of the Pacific Ocean Basin among the shelf regions off Japan and the Aleutian Islands. The dichotomy in habitat use between fledglings and adults from Midway Atoll results in complete spatial segregation between age‐classes and suggests ontogenetic niche separation in this species. This research fills a large knowledge gap in at‐sea habitat use during a little known yet critical life stage of albatrosses, and contributes to a more comprehensive understanding of differential mortality pressure between age‐classes and overall conservation status for the vulnerable Black‐footed Albatross.     

Heterogeneity of Multimedia Exposures to Neurotoxic Elements (Al,As, Cd,Pb, Mn,and Hg) in Breastfed Infants from Porto Velho,Brazil

Infant exposure to neurotoxic elements is a public health issue that needs monitoring with regard to breast milk composition. We studied six neurotoxic elements in breast milk samples at different stages of lactation in mothers from Porto Velho, Brazil. We used a flow-injection mercury system (FIMS) to determine total Hg concentrations and an inductively coupled plasma optical emission spectrometer (ICP-OES) to determine the concentrations of Al, As, Cd, Pb, and Mn in 106 donors of a human milk bank. Association rules analyses were applied to determine the pattern of binary and ternary mixtures of the measured exposants. The metal concentration was mostly below the limit of detection (LOD) for Cd (99%), Pb (84%), and Hg (72%), and it was above the LOD for As (53%), Mn (60%), and Al (82%), respectively. Median concentrations (dry weight) of Al, As, Hg, Mn, and Pb were 1.81 μg/g, 13.8 ng/g, 7.1 ng/g, 51.1 ng/g, and 0.43 μg/g, respectively. Al is singly the most frequent element to which infants are exposed. Occurring binary combination (> LOD) was 56% for Al-Mn, 41% for Al-As, 22% for Al-Hg, and 13% for Al-Pb. In 100% of neonates, exposure to Al-ethylmercury (EtHg) occurred through immunization with thimerosal-containing vaccines (TCV). Association rules analysis revealed that Al was present in all of the multilevel combinations and hierarchical levels and that it showed a strong link with other neurotoxic elements (especially with Mn, As, and Hg). (a) Nursing infants are exposed to combinations of neurotoxicants by different routes, dosages, and at different stages of development; (b) In breastfed infants, the binary exposures to Al and total Hg can occur through breast milk and additionally through TCV (EtHg and Al); (c) The measured neurotoxic elements were found at low frequencies in breast milk and at concentrations that pose no public health concerns for milk banking.     

Mesenchymal stromal cells from amniotic fluid are less prone to senescence compared to those obtained from bone marrow: An in vitro study

Mesenchymal stromal cells (MSCs) are considered to be an excellent source in regenerative medicine. They contain several cell subtypes, including multipotent stem cells. MSCs are of particular interest as they are currently being tested using cell and gene therapies for a number of human diseases. They represent a rare population in tissues; for this reason, they require, before being transplanted, an in vitro amplification. This process may induce replicative senescence, thus affecting differentiation and proliferative capacities. Increasing evidence suggests that MSCs from fetal tissues are significantly more plastic and grow faster than MSCs from bone marrow. Here, we compare amniotic fluid mesenchymal stromal cells (AF‐MSCs) and bone marrow mesenchymal stromal cells (BM‐MSCs) in terms of cell proliferation, surface markers, multidifferentiation potential, senescence, and DNA repair capacity. Our study shows that AF‐MSCs are less prone to senescence with respect to BM‐MSCs. Moreover, both cell models activate the same repair system after DNA damage, but AF‐MSCs are able to return to the basal condition more efficiently with respect to BM‐MSCs. Indeed, AF‐MSCs are better able to cope with genotoxic stress that may occur either during in vitro cultivation or following transplantation in patients. Our findings suggest that AF‐MSCs may represent a valid alternative to BM‐MSCs in regenerative medicine, and, of great relevance, the investigation of the mechanisms involved in DNA repair capacity of both AF‐MSCs and BM‐MSCs may pave the way to their rational use in the medical field.     

Biosilica deposition in the marine sponge Petrosia ficiformis (Poiret, 1789): the model of primmorphs reveals time dependence of spiculogenesis

Biomineralization is a phenomenon that spreads across all taxonomic kingdoms and has numerous potential applications in biotechnology. Using cell cultures (primmorphs) of Porifera as a model to study biosilicification, we hypothesised that different culture media can modulate siliceous spicule production both quantitatively and qualitatively. Long-term primmorph cultures of Petrosia ficiformis allowed comparing four experimental conditions: (1) natural seawater (SW) medium containing 5 μM silicate as control; (2) SW-Si 120 μM; (3) SW-Fe 5 μM; (4) SW-Si 60 μM Fe 2.5 μM evidencing several patterns of spiculogenesis. Here we have provided the first demonstration of how spiculogenesis processes are time-dependent and how spicules increase in number and size over time. The addition of dissolved silicon and low iron concentrations to the culture media produces larger spicules in greater numbers, affecting the proportions among spicule types as well. In particular, silicate seems to facilitate the production of fusiform oxeas, while iron stimulates the production of strongyloxeas. Considering the key role of spicules in taxonomic studies, our results point out the importance of environmental conditions in skeletal phenotypic plasticity, modulating the norm of reaction of the species.     

Dual-color bioluminescent assay using infected HepG2 cells sheds new light on Chlamydia pneumoniae and human cytomegalovirus effects on human cholesterol 7α-hydroxylase (CYP7A1) transcription

Human bones, recovered from excavations, are an important biological archive of information. In particular, the analysis of the collagen fraction is useful for paleodietary reconstruction, via light stable isotopes, and for (14)C dating. Generally, collagen extraction procedures do not prevent loss of integrity of proteins. As a consequence, information about the state-of-remains preservation is unavailable. Here we describe a "soft" nondestructive CH(3)COOH-based method to recover collagen from archaeological bones, and also to obtain material for successive isotopic analyses. Our isotopic measurements on the extracts indicate that the CH(3)COOH-based method of extraction may be routinely employed in the context of paleodiet studies. In addition, we propose that biochemical characterization by denaturant electrophoresis and Western blot on CH(3)COOH extracts may be used as a bone collagen quality indicator.     

Synthesis and binding affinity at α4β2 and α7 nicotinic acetylcholine receptors of new analogs of epibatidine and epiboxidine containing the 7-azabicyclo[2.2.1]hept-2-ene ring system

A group of novel racemic nicotinic ligands structurally related to epibatidine or epiboxidine [(±)-10-(±)-17] was synthesized through a palladium-catalyzed cross-coupling between the appropriate vinyl triflate and a range of organometallic heterocycles. The target compounds were evaluated for binding affinity at the α4β2 and α7 neuronal nicotinic receptors (nAChRs). The set of 3-pyridinyl derivatives (±)-10, (±)-11 and (±)-12 exhibited an affinity for the α4β2 nAChR subtype in the subnanomolar range (K(i) values of 0.20, 0.40 and 0.50nM, respectively) and behaved as α4β2 versus α7 subtype selective ligands. Interestingly, the epiboxidine-related dimethylammonium iodide (±)-17, which retained a good affinity for the α4β2 nAChR (K(i)=13.30nM), tightly bound also to the α7 subtype (K(i)=1.60nM), thus displaying a reversal of the affinity trend among the reference and new nicotinic ligands under investigation.