<Emphasis Type="Italic">Typhonium stigmatilobatum</Emphasis> (<Emphasis Type="Italic">Araceae</Emphasis> tribe <Emphasis Type="Italic">Areae</Emphasis>), a new species from Vietnam

Summary   Typhonium stigmatilobatum V. D. Nguyen, a new species from Vietnam, is described and illustrated.     

The plant Apolipoprotein D ortholog protects <Emphasis Type="Italic">Arabidopsis</Emphasis> against oxidative stress

Background  

Lipocalins are a large and diverse family of small, mostly extracellular proteins implicated in many important functions. This family has been studied in bacteria, invertebrate and vertebrate animals but little is known about these proteins in plants. We recently reported the identification and molecular characterization of the first true lipocalins from plants, including the Apolipoprotein D ortholog AtTIL identified in the plant model Arabidopsis thaliana. This study aimed to determine its physiological role in planta.     

Activin signals via SMAD2/3 between germ and somatic cells in the human fetal ovary and regulates kit ligand expression

Ovarian germ cell survival is dependent upon the formation of primordial follicles, which occurs during fetal life in the human. Activin contributes to germ cell proliferation and survival at this time. SMADs2 and 3 are central elements in the activin signalling pathway and thus indicate sites of activin action. We have investigated the expression and localisation of SMADs2 and 3 in the fetal ovary between 14 and 20 weeks gestation, i.e. preceding and during primordial follicle formation. SMAD3 mRNA expression increased 1.9 fold (P = 0.02). SMAD2 and 3 proteins were localised by immunofluorescence to the nuclei of three distinct populations of somatic cells: (a) stromal cells between clusters of germ cells; (b) some somatic cells intermingled with activin βA-expressing germ cells; (c) pre-granulosa cells surrounding primordial follicles. Germ cells did not express SMAD2 or 3. Activin A increased and follistatin decreased phosphorylation of SMAD2/3 in vitro, and activin increased SMAD2 and decreased KITLG mRNA expression. It therefore appears that somatic cells are the targets for activin signalling in the developing ovary. The effects of activin on germ cells are indirect and include mediation by the kit ligand/c-Kit pathway, rather than being an autocrine germ cell effect.     

The first crystal structure of gluconolactonase important in the glucose secondary metabolic pathways

The first gluconolactonase crystal structure from bacteria has been determined to a resolution of 1.61 Å using X-ray crystallography. It belongs to the senescence marker protein 30/gluconolaconase superfamily but exhibits substrate specificity mainly toward d-glucono-δ-lactone. It forms a novel disulfide-bonded clamshell dimer comprising two doughnut-shaped six-bladed β-propeller domains, yet with an exceptionally long N-terminal subdomain forming an extra helix and four additional β-strands to enclose half of the outermost β-strands of each propeller. Extensive interactions, including H-bonds, salt bridges, disulfide bonds, and coordination bonds, along with numerous bridging water molecules, are present in the interface to institute the “top-to-top” clamshell-type dimer. Three calcium ions per subunit were observed. Two are present in the central water-filled channel, with the top one coordinated to four highly conserved amino acids and is possibly involved in substrate hydrolysis, while the bottom one is coordinated to the backbone oxygen atoms, which is possibly for stabilizing the propeller domain. One calcium ion is situated in the interface also to stabilize the dimer form. Since gluconolactonase is essential in the glucose secondary metabolic pathways leading to the synthesis of pentose, vitamin C, or “antiaging” factors, determination of its tertiary structure should help understand these important biochemical processes.     

Effect of some essential oils on mycelial growth of <Emphasis Type="Italic">Penicillium digitatum</Emphasis> Sacc.

The antifungal action of four essential oils of Foeniculum vulgare (fennel), Thymus vulgaris (thyme), Eugenia caryophyllata (Clove) and Salvia officinalis (sage) was tested in vitro against Penicillium digitatum Sacc. Direct contact and vapour phase were used to test the antifungal activity of these essential oils against P. digitatum that is responsible for green mould rot of citrus fruits. The vapour phase and direct contact of clove and thyme essential oils exhibited the strongest toxicity and totally inhibited the mycelial growth of the test fungus. Thyme and clove essential oils completely inhibited P. digitatum growth either when added into the medium 600 μl l⁻¹ or by their volatiles with 24 μl per 8 cm diameter Petri dish. In in vitro mycelial growth assay showed fungistatic and fungicidal activity by clove and thyme essential oils. Sage and fennel oils did not show any inhibitory activity on this fungus. Scanning electron microscopy (SEM) was done to study the mode of action of clove oil in P. digitatum and it was observed that treatment with the oil leads to large alterations in hyphal morphology.     

Sophisticated selectionism as a general theory of knowledge

Human knowledge is a phenomenon whose roots extend from the cultural, through the neural and the biological and finally all the way down into the Precambrian “primordial soup.” The present paper reports an attempt at understanding this Greater System of Knowledge (GSK) as a hierarchical nested set of selection processes acting concurrently on several different scales of time and space. To this end, a general selection theory extending mainly from the work of Hull and Campbell is introduced. The perhaps most drastic change from previous similar theories is that replication is revealed as a composite function consisting of what is referred to as memory and synthesis. This move is argued to drastically improve the fit between theory and human-related knowledge systems. The introduced theory is then used to interpret the subsystems of the GSK and their interrelations. This is done to the end of demonstrating some of the new perspectives offered by this view.

Phylogenetic analysis of epiphytic marine bacteria on Hole-Rotten diseased sporophytes of <Emphasis Type="Italic">Laminaria japonica</Emphasis>

During an occurrence of Hole-Rotten Disease of Laminaria japonica in a cultivating farm in Ma Shan Shandong province, China, 42 Gram-negative epiphytic marine bacteria were isolated and purified on Zobell 2216E marine agar medium. Morphological and biochemical characteristics of each isolated bacterium were studied, and molecular identification of bacterial strains was conducted with polymerase chain reaction amplification to 16S rRNA gene sequence analysis. Based on nearly full length of 16S rRNA gene sequence analysis, the isolated strains were bacteria that belong to genus Pseudoalteromonas, Vibrio, Halomonas and Bacillus. The percentage of each group was 61.9%, 28.6%, 7.1% and 2.4% respectively. The results of pathogenicity assay showed that 12 strains could cause the disease symptoms in sporophytes of L. japonica. They belonged to the genera Pseudoalteromonas, Vibrio and Halomonas with 58.3%, 33.3%, 8.3% respectively. The results suggest that these bacteria are the dominant marine bacteria on diseased sporophytes of L. japonica and may be the potential pathogenic bacteria associated with Hole-Rotten Disease of L. japonica.     

Lung Ischemia: A Model for Endothelial Mechanotransduction

Endothelial cells in vivo are constantly exposed to shear associated with blood flow and altered shear stress elicits cellular responses (mechanotransduction). This review describes the role of shear sensors and signal transducers in these events. The major focus is the response to removal of shear as occurs when blood flow is compromised (i.e., ischemia). Pulmonary ischemia studied with the isolated murine lung or flow adapted pulmonary microvascular endothelial cells in vitro results in endothelial generation of reactive oxygen species (ROS) and NO. The response requires caveolae and is initiated by endothelial cell depolarization via K_ATP channel closure followed by activation of NADPH oxidase (NOX2) and NO synthase (eNOS), signaling through MAP kinases, and endothelial cell proliferation. These physiological mediators can promote vasodilation and angiogenesis as compensation for decreased tissue perfusion.     

Integrating economic input–output life cycle assessment with risk assessment for a screening-level analysis

Goal, Scope, and Background  The paper describes the integration of the economic input–output life cycle assessment (EIO-LCA) model and the environmental fate and transport model (CHEMGL) with a risk assessment tool. Utilizing the EIO-LCA, instead of a traditional LCA, enables a rapid, screening-level analysis of an emerging chemical of concern, decabromodiphenyl ether (DecaBDE). The risk assessment in this study is evaluated based on the mass of chemical released, estimated concentrations, exposure, and chemical toxicity. Methods  The relative risk from ten economic sectors identified within the EIO-LCA model, 55 chemicals utilized in those sectors and DecaBDE along with four potential DecaBDE breakdown products, were evaluated for the life cycle stages and exposure pathways. The relative risk (expressed as toluene equivalents) of the different chemicals, sectors, and life cycle stages were compared to assess those representing the greatest overall relative risks to humans (via inhalation and ingestion) and fish. Results  The greatest overall risk to human health resulted from the manufacturing and production stages. For fish, the manufacturing stage represented virtually all of the risk. Of the 56 chemicals evaluated, DecaBDE represented the majority of the total risk to humans. However, DecaBDE posed the least risk compared to its potential breakdown products. Discussion  The risk to humans from ingestion, which represented the greatest risk, from the production, manufacturing, and consumption stages can be controlled and reduced through various safety precautions in the workplace. Additionally, the increasing concentration of DecaBDE in anaerobic compartments represents a threat to humans and fish via the higher risk DecaBDE breakdown products. Conclusions  Overall, the manufacturing and production life cycle stages pose the greatest risk to humans and fish. The sediment compartment received the highest DecaBDE concentration for the production, manufacturing, and consumption stages. This case study demonstrates that the integrated EIO-LCA with risk assessment is suitable for screening-level analysis of emerging chemicals due to rapid life cycle inventory analysis. Recommendations  The production and manufacturing stages allow for greater industry control and government regulation, compared to the consumption stage, because there are fewer point sources. This integrated life cycle methodology may allow chemical designers to evaluate each stage and assess areas where risks can be minimized.     

<Emphasis Type="Italic">Paenibacillus</Emphasis>—a predominant endophytic bacterium colonising tissue cultures of woody plants

High densities of endophytic bacteria were found in plant material from poplar, larch and spruce that had been micropropagated for at least 5 years. The majority of these bacteria were assigned to the genus Paenibacillus based on the sequencing of the 16S rRNA genes. Other endophytic bacteria such as Methylobacterium, Stenotrophomonas or Bacillus could also be found but only in some tissue cultures. Certain species or strains of Paenibacillus, especially those with a close relationship to P. humicus, seemed to accumulate under in vitro conditions without visible negative influences on the plant’s development. Poplar microcuttings inoculated with the endophytic Paenibacillus isolate 22 showed significantly more roots per cutting and higher root length in comparison to the control plants after 3 weeks.