Yolk hydrolases in the eggs of Anticarsia gemmatalis hubner (Lepidoptera: Noctuidae): A role for inorganic polyphosphate towards yolk mobilization

Despite being the main insect pest on soybean crops in the Americas, very few studies have approached the general biology of the lepidopteran Anticarsia gemmatalis and there is a paucity of studies with embryo formation and yolk mobilization in this species. In the present work, we identified an acid phosphatase activity in the eggs of A. gemmatalis (agAP) that we further characterized by means of biochemistry and cell biology experiments. By testing several candidate substrates, this enzyme proved chiefly active with phosphotyrosine; in vitro assays suggested a link between agAP activity and dephosphorylation of egg yolk phosphotyrosine. We also detected strong activity with endogenous and exogenous short chain polyphosphates (PolyP), which are polymers of phosphate residues involved in a number of physiological processes. Both agAP activity and PolyP were shown to initially concentrate in small vesicles clearly distinct from typically larger yolk granules, suggesting subcellular compartmentalization. As PolyP has been implicated in inhibition of yolk proteases, we performed in vitro enzymatic assays with a cysteine protease to test whether it would be inhibited by PolyP. This cysteine protease is prominent in Anticarsia egg homogenates. Accordingly, short chain PolyP was a potent inhibitor of cysteine protease. We thereby suggest that PolyP hydrolysis by agAP is a triggering mechanism of yolk mobilization in A. gemmatalis.     

Films of starch and poly(butylene adipate co-terephthalate) added of soybean oil (SO) and Tween 80

Starch extruded in the presence of a plasticizer results in a material called thermoplastic starch (TPS). TPS mixed with poly(butylene adipate co-terephthalate) (PBAT), soybean oil (SO), and surfactant may result in films with improved mechanical properties due to greater hydrophobicity and compatibility among the polymers. This study characterized films produced from blends containing 65% TPS and 35% PBAT with SO added as compatibilizer. The Tween 80 was added to prevention of phase separation. The elongation and resistance were greater in the films with SO. The infrared spectra confirmed an increase in ester groups bonded to the PBAT and the presence of groups bonded to the starch ring, indicating TPS-SO and PBAT-SO interactions. The micrographs suggest that the films with SO were more homogenous. Thus, SO is considered to be a good compatibilizer for blends of TPS and PBAT.     

Dopamine Transporter Is Required for In Vivo MPTP Neurotoxicity: Evidence from Mice Lacking the Transporter

Abstract: The neurotoxic effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was tested on mice lacking the dopamine (DA) transporter (DAT−/− mice). Striatal tissue DA content and glial fibrillary acidic protein (GFAP) mRNA expression were assessed as markers of MPTP neurotoxicity. MPTP (30 mg/kg, s.c., b.i.d.) produced an 87% decrease in tissue DA levels and a 29-fold increase in the level of GFAP mRNA in the striatum of wild-type animals 48 h after administration. Conversely, there were no significant changes in either parameter in DAT−/− mice. Heterozygotes demonstrated partial sensitivity to MPTP administration as shown by an intermediate value (48%) of tissue DA loss. Direct intrastriatal infusion of the active metabolite of MPTP, 1-methyl-4-phenylpyridinium (MPP⁺; 10 m M ), via a microdialysis probe produced a massive efflux of DA in wild-type mice (>320-fold). In the DAT−/− mice the same treatment produced a much smaller increase in extracellular DA (sixfold), which is likely secondary to tissue damage due to the implantation of the dialysis probe. These observations show that the DAT is a mandatory component for expression of MPTP toxicity in vivo.     

Impact of the leaf miner <Emphasis Type="Italic">Cameraria ohridella</Emphasis> on whole-plant photosynthetic productivity of <Emphasis Type="Italic">Aesculus hippocastanum</Emphasis>: insights from a model

The leaf miner Cameraria ohridella causes premature defoliation of Aesculus hippocastanum trees. In order to assess the whole-plant loss of productivity caused by the parasite, we monitored seasonal changes of leaf gas exchange and leaf area losses in horse chestnut trees freely infested or chemically treated to prevent moth infestation (controls). Data were integrated in a model and the annual loss of net primary productivity (NPP) was calculated for infested trees with respect to controls. Measurements showed marked vertical stratification of C. ohridella attacks, with lower crown strata being more infested than higher ones. Leaf gas exchange was maximum between May and early June, but it strongly decreased starting from mid-June even in controls. Model calculations showed that NPP loss of infested trees was about 30% on an annual basis (when the first moth attack is recorded at the end of April). Model simulations showed that postponing the start day of attack would have important positive effects on plants NPP. For example, if the start day of attack was postponed to 20 May, the annual loss of NPP would be about 15%. Our study suggests that A. hippocastanum trees attacked by C. ohridella are not facing serious risks of decline, especially if methods are adopted to postpone the start day of attack (e.g. removal of fallen leaves in autumn). Our data do not support the view that plants need to be totally protected from the parasite by application of insecticides.     

Chelating derivatives of chitosan obtained by reaction with ascorbic acid

Ascorbic acid immediately dissolves Euphausia superba chitosan upon mixing and forms chitosan ascorbate; during the 6-h period after dissolution in water at pH 5–7, ascorbate is oxidized to dehydroascorbate which undergoes Schiff reaction with the amino groups of chitosan, thus yielding a viscous solution of a polymeric ketimine. The latter is characterized by infrared spectrometry, circular dichroism spectropolarimetry, viscometry and alkalimetry. When brought into contact with transition metal ions, the chitosan ascorbate ketimine yields insoluble metal chelates. Upon reduction with sodium cyanoborohydride, the water-insoluble N-[2-(1,2-dihydroxyethyl)tetrahydrofuryl] chitosan (NDTC) is obtained, which shows enhanced capacity for uranium, up to 800 mg U/g from solutions at pH 4·5.     

Interface processes between protected and unprotected areas: A global review and ways forward

Land‐use changes and the expansion of protected areas (PAs) have amplified the interaction between protected and unprotected areas worldwide. In this context, ‘interface processes' (human–nature and cross‐boundary interactions inside and around PAs) have become central to issues around the conservation of biodiversity and ecosystem services. This scientific literature review aimed to explore current knowledge and research gaps on interface processes regarding terrestrial PAs. At first, 3,515 references related to the topic were extracted through a standardized search on the Web of Science and analyzed with scientometric techniques. Next, a full‐text analysis was conducted on a sample of 240 research papers. A keyword analysis revealed a wide diversity of research topics, from ‘pure' ecology to sociopolitical research. We found a bias in the geographical distribution of research, with half the papers focusing on eight countries. Additionally, we found that the spatial extent of cross‐boundary interactions was rarely assessed, preventing any clear delimitation of PA interactive zones. In the 240 research papers we scanned, we identified 403 processes that were studied. The ecological effects of PAs were well documented and appeared to be positive overall. In contrast, the effects of PAs on local communities were understudied and, according to the literature focusing on these, were very variable according to local contexts. Our findings highlight key research advances on interface processes, especially regarding the ecological outcomes of PAs, the influence of human activities on biodiversity, and PA governance issues. In contrast, main knowledge gaps concern the spatial extent of interactive zones, as well as the interactions between local people and conservation actions and how to promote synergies between them. While the review was limited to terrestrial PAs, its findings allow us to propose research priorities for tackling environmental and socioeconomic challenges in the face of a rapidly changing world.     

The future of ecolabels

The International Journal of Life Cycle Assessment -