Carbonate organo-mineral micro- and ultrastructures in sub-fossil stromatolites: Marion lake, South Australia

Sub-fossil stromatolites (5000-3000 years old) occur on the marginal flat surrounding Marion Lake (South Australia). A micrite/microsparite crystal fabric characterises these fine-grained, well-laminated stromatolites, which lack trapped grains. The internal lamination is characterised by a sub-millimetric alternation of porous and dense laminae. The microfabric of the laminae is ubiquitously composed of a fine (10-20 μm) peloidal texture, with many thinner aphanitic layers. Aggregates of very fine, low-Mg calcite and aragonite constitute both peloidal and aphanitic micrite, which is coated, respectively, by spherulitic and fringing acicular microspar. Micrite, with a high organic matter content, is formed of coalescing nanospheres grading into small polyhedrons, probably composed mainly of aragonite, with less calcite enriched in Mg, Sr, Na and S. Bacteria-like microfossils and relics of extracellular polymeric substance (EPS) occur abundantly within this micritic framework. The former consist of empty moulds and mineralised bodies of coccoid forms, whereas EPS relics consist of sheet-like or filamentous structures that appear both mineralised and more often still preserved as a C-enriched dehydrated substance that represents the main organic matter component of the deposit. Acicular crystals, which show a prismatic elongate shape, are composed of Mg-depleted aragonite that lacks fossils or organic relicts. Degrading EPS and micro-organisms appear gradually to be replaced and entombed by the nanospherical precipitates, implying the existence of processes of organo-mineralisation within an original syn-sedimentary microbial community. Succeeding micron-scale crystals merge to form isolated or connected micritic aggregates (the peloids), followed by the gradual formation of the acicular crystals as purely inorganic precipitates.     

Immunosuppressive diacetylenes, ceramides and cerebrosides from Hydrocotyle leucocephala

Three C-17 diacetylenic compounds (1-3), one monoterpenoid (4), seven ceramides (leucoceramides A-G, 5a-g), six cerebrosides (leucocerebrosides A-F, 6a-f) and nine known compounds were isolated from the methanolic extract of Hydrocotyle leucocephala. Their structures were established by spectroscopic methods. The isolated compounds 1-3, 5a-g, 6a-f and 7 were shown to be active in the lipopolysaccharide (LPS) induced cytokine production assay for IL-10, IL-12, and TNF-alpha.     

Sperm cells as vectors for introducing foreign DNA into eggs: genetic transformation of mice

Mature mouse sperm cells incubated in an isotonic buffer with cloned DNA capture DNA molecules over a 15 min period. Spermatozoa incubated with pSV2CAT plasmid in either circular or linear form were used to fertilize mouse eggs in vitro. Sequences complementary to pSV2CAT were identified in approximately 30% of 250 progeny by Southern blotting. A genomic library was constructed from the DNA of a positive mouse. Three positive clones were identified and two adjacent HincII restriction fragments of 240 and 370 bp showed identical sequences to the corresponding fragments of the pSV2CAT plasmid. F1 progeny showed paternal and maternal transmission of the transgenes from founders. CAT gene expression was detected on tissues of adult F1 individuals, preferentially on tails and muscle. We conclude that transgenic mice can be obtained using sperm cells as foreign DNA vectors.     

Induction of autophagic cell death by a novel molecule is increased by hypoxia

Adaptation to hypoxia through activation of the hypoxia inducible factor-1 (HIF-1) is crucial for tumor cells survival. Here we describe the antitumoral effects of the new molecule CR 3294 on tumor cells in the presence of hypoxia. Treatment of the breast carcinoma cell line MDA-MB-231 with CR 3294 in 1% O(2) resulted in an in vivo and in vitro inhibition of tumor growth. CR 3294 induced accumulation of autophagosomes in hypoxic MDA-MB-231 cells as assessed by both transmission electron microscopy (TEM) and the autophagic marker LC3-II. TEM analysis revealed the presence of invaginations of the cytoplasm into the nucleus. Autophagosomes were present in such invaginations. Moreover, CR 3294 inhibited both the DNA binding of HIF-1alpha and VEGF mRNA synthesis. Immunoprecipitation and immunofluorescence studies showed an interaction between LC3 and HIF-1alpha. We next detailed the effect of inhibitors and activators of autophagy on both HIF-1alpha and LC3. In particular, 3 methyladenine (3MA) and wortmannin, two macroautophagic inhibitors, prevented both the decrease of HIF-1alpha protein levels and LC3 processing in cells treated with CR 3294. Bafilomycin and leupeptin, inhibitors of lysosomes, prevented HIF-1alpha decrease without affecting LC3 processing. By contrast, treating hypoxic MDA-MB-231 cells with trifluoperazine (TFP) or serum withdrawal (SW), two activators of autophagy, diminished HIF-1alpha levels and stimulated LC3 processing. These results indicate that activation of the autophagic pathway in hypoxic cells by the new molecule CR 3294, as well as by TFP or SW, can have potentially important implications for cancer treatment.     

Champanones, yellow pigments from the seeds of champa (Campomanesia lineatifolia)

Chemical investigation of the methanol extract of the seeds of Campomanesia lineatifolia Ruiz and Pav. (Myrtaceae) led to the isolation of two new beta-triketone type compounds, named champanones A (1) and B (2), together with the known 2,3-dihydro-5-hydroxy-6,8,8-trimethyl-2-phenyl-4H-1-benzopyran-4,7(8H)-dione (champanone C) (3). The structures of 1 and 2 were determined to be 2,2,4,4-tetramethyl-6-(1-oxo-3-phenylprop-2-enyl) cyclohexane-1,3,5-trione (occurs as an enol form) and 2,2,4-trimethyl-6-(1-oxo-3-phenylprop-2-enyl)cyclohexane-1,3,5-trione (occurs as an enol form), respectively, by means of spectroscopic analysis. The three compounds showed mild antimicrobial activity.     

How much land‐based greenhouse gas mitigation can be achieved without compromising food security and environmental goals?

Feeding 9–10 billion people by 2050 and preventing dangerous climate change are two of the greatest challenges facing humanity. Both challenges must be met while reducing the impact of land management on ecosystem services that deliver vital goods and services, and support human health and well‐being. Few studies to date have considered the interactions between these challenges. In this study we briefly outline the challenges, review the supply‐ and demand‐side climate mitigation potential available in the Agriculture, Forestry and Other Land Use AFOLU sector and options for delivering food security. We briefly outline some of the synergies and trade‐offs afforded by mitigation practices, before presenting an assessment of the mitigation potential possible in the AFOLU sector under possible future scenarios in which demand‐side measures codeliver to aid food security. We conclude that while supply‐side mitigation measures, such as changes in land management, might either enhance or negatively impact food security, demand‐side mitigation measures, such as reduced waste or demand for livestock products, should benefit both food security and greenhouse gas (GHG) mitigation. Demand‐side measures offer a greater potential (1.5–15.6 Gt CO₂‐eq. yr^?1) in meeting both challenges than do supply‐side measures (1.5–4.3 Gt CO₂‐eq. yr^?1 at carbon prices between 20 and 100 US$ tCO₂‐eq. yr^?1), but given the enormity of challenges, all options need to be considered. Supply‐side measures should be implemented immediately, focussing on those that allow the production of more agricultural product per unit of input. For demand‐side measures, given the difficulties in their implementation and lag in their effectiveness, policy should be introduced quickly, and should aim to codeliver to other policy agenda, such as improving environmental quality or improving dietary health. These problems facing humanity in the 21st Century are extremely challenging, and policy that addresses multiple objectives is required now more than ever.     

Quantitative trait loci (QTLs) analysis of palm oil fatty acid composition in an interspecific pseudo-backcross from Elaeis oleifera (H.B.K.) Cortés and oil palm (Elaeis guineensis Jacq.)

We chose an Elaeis interspecific pseudo-backcross of first generation (E. oleifera × E. guineensis) × E. guineensis to identify quantitative trait loci (QTLs) for fatty acid composition of palm oil. A dense microsatellite linkage map of 362 loci spanned 1.485 cM, representing the 16 pairs of homologous chromosomes in the Elaeis genus from which we traced segregating alleles from both E. oleifera and E. guineensis grandparents. The relative linear orders of mapped loci suggested the probable absence of chromosome rearrangements between the E. oleifera and E. guineensis genomes. A total of 19 QTL associated to the palm oil fatty acid composition were evidenced. The QTL positions and the species origin as well as the estimated effects of the QTL marker alleles were in coherence with the knowledge of the oil biosynthesis pathway in plants and with the individual phenotypic correlations between the traits. The mapping of chosen Elaeis key genes related to oleic acid C18:1, using intra-gene SNPs, supported several QTLs underlying notably FATA and SAD enzymes. The high number of hyper-variable SSR loci of known relative linear orders and the QTL information make these resources valuable for such mapping study in other Elaeis breeding materials.     

Genetic Architecture of Palm Oil Fatty Acid Composition in Cultivated Oil Palm (Elaeis guineensis Jacq.) Compared to Its Wild Relative E. oleifera (H.B.K) Cortés

We searched for quantitative trait loci (QTL) associated with the palm oil fatty acid composition of mature fruits of the oil palm E. guineensis Jacq. in comparison with its wild relative E. oleifera (H.B.K) Cortés. The oil palm cross LM2T x DA10D between two heterozygous parents was considered in our experiment as an intraspecific representative of E. guineensis. Its QTLs were compared to QTLs published for the same traits in an interspecific Elaeis pseudo-backcross used as an indirect representative of E. oleifera. Few correlations were found in E. guineensis between pulp fatty acid proportions and yield traits, allowing for the rather independent selection of both types of traits. Sixteen QTLs affecting palm oil fatty acid proportions and iodine value were identified in oil palm. The phenotypic variation explained by the detected QTLs was low to medium in E. guineensis, ranging between 10% and 36%. The explained cumulative variation was 29% for palmitic acid C16:0 (one QTL), 68% for stearic acid C18:0 (two QTLs), 50% for oleic acid C18:1 (three QTLs), 25% for linoleic acid C18:2 (one QTL), and 40% (two QTLs) for the iodine value. Good marker co-linearity was observed between the intraspecific and interspecific Simple Sequence Repeat (SSR) linkage maps. Specific QTL regions for several traits were found in each mapping population. Our comparative QTL results in both E. guineensis and interspecific materials strongly suggest that, apart from two common QTL zones, there are two specific QTL regions with major effects, which might be one in E. guineensis, the other in E. oleifera, which are independent of each other and harbor QTLs for several traits, indicating either pleiotropic effects or linkage. Using QTL maps connected by highly transferable SSR markers, our study established a good basis to decipher in the future such hypothesis at the Elaeis genus level.