Phytofiltration of anaerobically digested sugarcane ethanol stillage using a macrophyte with high potential for biofuel production

Anaerobically digested stillage (ADS) requires treatment before being discharged into water bodies or soils to avoid adverse effects. Phytofiltration systems are eco-friendly technologies for wastewater treatment, and they simultaneously serve as a source of biomass for biofuel production. The aim of the present study was to investigate the phytofiltration of ADS using Azolla sp. The effects of the ADS strength (dilutions 1:?50 and 1?:?25 v/v) and initial biomass density (IBD) [15.44 (IBD1) and 23.16 (IBD2) g dry weight (dw) m^?2] on plant growth and pollutant removal were assessed. Productivities obtained at ADS 1:?50 (2.93 and 3.04 g m^?2 d^?1 for IBD1 and IBD2, respectively) were not significantly different from those of a synthetic medium (2.56 and 3.15 g m^?2 for IBD1 and IBD2, respectively). Higher organic matter removal was found using ADS at 1:?25 than that obtained using ADS 1:?50 (52.16–53.34 vs 32.29–38.16%), while no IBD effect was observed. The nutrient concentrations in ADS were reduced significantly, especially the concentrations of NH₄-N (75.11–82.54%), PO₄-P (88.72–92.90%) and SO₄-S (55.95–66.61%). The conversion of nutrients from ADS into Azolla biomass may result in an effective way to produce an attractive feedstock for biofuel production.     

Adult Sox2+ stem cell exhaustion in mice results in cellular senescence and premature aging

Aging is characterized by a gradual functional decline of tissues with age. Adult stem and progenitor cells are responsible for tissue maintenance, repair, and regeneration, but during aging, this population of cells is decreased or its activity is reduced, compromising tissue integrity and causing pathologies that increase vulnerability, and ultimately lead to death. The causes of stem cell exhaustion during aging are not clear, and whether a reduction in stem cell function is a cause or a consequence of aging remains unresolved. Here, we took advantage of a mouse model of induced adult Sox2+ stem cell depletion to address whether accelerated stem cell depletion can promote premature aging. After a short period of partial repetitive depletion of this adult stem cell population in mice, we observed increased kyphosis and hair graying, and reduced fat mass, all of them signs of premature aging. It is interesting that cellular senescence was identified in kidney after this partial repetitive Sox2+ cell depletion. To confirm these observations, we performed a prolonged protocol of partial repetitive depletion of Sox2+ cells, forcing regeneration from the remaining Sox2+ cells, thereby causing their exhaustion. Senescence specific staining and the analysis of the expression of genetic markers clearly corroborated that adult stem cell exhaustion can lead to cellular senescence induction and premature aging.     

Substantia nigra dopaminergic neurons and striatal interneurons are engaged in three parallel but interdependent postnatal neurotrophic circuits

The striatum integrates motor behavior using a well‐defined microcircuit whose individual components are independently affected in several neurological diseases. The glial cell line‐derived neurotrophic factor (GDNF), synthesized by striatal interneurons, and Sonic hedgehog (Shh), produced by the dopaminergic neurons of the substantia nigra (DA SNpc), are both involved in the nigrostriatal maintenance but the reciprocal neurotrophic relationships among these neurons are only partially understood. To define the postnatal neurotrophic connections among fast‐spiking GABAergic interneurons (FS), cholinergic interneurons (ACh), and DA SNpc, we used a genetically induced mouse model of postnatal DA SNpc neurodegeneration and separately eliminated Smoothened (Smo), the obligatory transducer of Shh signaling, in striatal interneurons. We show that FS postnatal survival relies on DA SNpc and is independent of Shh signaling. On the contrary, Shh signaling but not dopaminergic striatal innervation is required to maintain ACh in the postnatal striatum. ACh are required for DA SNpc survival in a GDNF‐independent manner. These data demonstrate the existence of three parallel but interdependent neurotrophic relationships between SN and striatal interneurons, partially defined by Shh and GDNF. The definition of these new neurotrophic interactions opens the search for new molecules involved in the striatal modulatory circuit maintenance with potential therapeutic value.     

Stabilization of multimeric sucrose synthase from Acidithiobacillus caldus via immobilization and post-immobilization techniques for synthesis of UDP-glucose

Sucrose synthases (SuSys) have been attracting great interest in recent years in industrial biocatalysis. They can be used for the cost-effective production of uridine 5′-diphosphate glucose (UDP-glucose) or its in situ recycling if coupled to glycosyltransferases on the production of glycosides in the food, pharmaceutical, nutraceutical, and cosmetic industry. In this study, the homotetrameric SuSy from Acidithiobacillus caldus (SuSyAc) was immobilized-stabilized on agarose beads activated with either (i) glyoxyl groups, (ii) cyanogen bromide groups, or (iii) heterogeneously activated with both glyoxyl and positively charged amino groups. The multipoint covalent immobilization of SuSyAc on glyoxyl agarose at pH 10.0 under optimized conditions provided a significant stabilization factor at reaction conditions (pH 5.0 and 45 °C). However, this strategy did not stabilize the enzyme quaternary structure. Thus, a post-immobilization technique using functionalized polymers, such as polyethyleneimine (PEI) and dextran-aldehyde (dexCHO), was applied to cross-link all enzyme subunits. The coating of the optimal SuSyAc immobilized glyoxyl agarose with a bilayer of 25 kDa PEI and 25 kDa dexCHO completely stabilized the quaternary structure of the enzyme. Accordingly, the combination of immobilization and post-immobilization techniques led to a biocatalyst 340-fold more stable than the non-cross-linked biocatalyst, preserving 60% of its initial activity. This biocatalyst produced 256 mM of UDP-glucose in a single batch, accumulating 1 M after five reaction cycles. Therefore, this immobilized enzyme can be of great interest as a biocatalyst to synthesize UDP-glucose.

     

Length‐weight relationship for sea catfishes (Siluriformes: Ariidae) from the southeastern Gulf of California with new records on maximum length

The parameters of length‐weight relationship (LWR) are presented for seven species of catfish from the southeastern Gulf of California. Samples were obtained every three months, in Bahia de Matanchen (using bottom trawl nets consistent of 72 hauls, with mesh sizes of 3.2 cm in the wings and 2.54 cm in the cod‐end) from February to November, 2016 and in the San Blas estuarine system (using gill nets consistent of 32 hauls, with mesh sizes of 5 cm) from August, 2015 to May, 2016 respectively. The allometric coefficient (b) of LWR varied from 2.797 for the Cominate Sea Catfish (Occidentarius platypogon (Günther, 1864)) to 3.373 for the Tete Sea Catfish (Ariopsis gilberti (Jordan & Williams, 1895)). Four species reached new records on maximum total length (Tete Sea Catfish, A. gilberti; Widehead Sea Catfish, A. guatemalensis (Günther, 1864); Conguito Sea Catfish, Cathorops liropus (Bristol, 1897); and Curator Sea Catfish, C. raredonae Marceniuk, Betancur‐R, & Acero, 2009). For six of these species this accounts for the first report on estimations of LWR parameters.     

Effect of cellobiose supplementation and dietary soluble fibre content on in vitro caecal fermentation of carbohydrate-rich substrates in rabbits

The in vitro caecal fermentation of five substrates low in starch and protein content [d-(+)-glucose (GLU), d-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS)] was investigated using soft faeces from rabbits receiving different levels of cellobiose and soluble fibre as inoculum. A total of 24 rabbits were supplemented 3 levels of cellobiose in the drinking water (0.0, 7.5, 15.0 g/l) and fed two experimental diets containing either low soluble fibre (LSF) or high soluble fibre (HSF) levels (84.0 and 130 g/kg dry matter). All substrates were subjected to a two-step pepsin/pancreatin in vitro pre-digestion, and the whole residue was used as substrate for the in vitro incubations. Gas production was measured until 144 h, and volatile fatty acid (VFA) production was determined at 24 h incubation. Experimental treatments did not affect SBP fermentation and had only a subtle influence on fermentation of WS and GLU. In contrast, cellobiose supplementation × donors’ diet interactions were detected for most gas production parameters for CEL. Both the fractional gas production (k) and maximal gas production rates were linearly increased (p ≤ 0.042) and the initial delay in the onset of gas production (Lag) linearly decreased (p < 0.001) by cellobiose supplementation with the HSF inoculum, with no differences between the 7.5 and 15.0 doses. In contrast, with the LSF inoculum cellobiose supplementation only affected k values, which were quadratically increased (p = 0.043) and had maximal values for the 7.5 dose. A quadratic effect (p ≤ 0.018) of cellobiose supplementation was observed for total VFA production at 24 h when CEL and PEC were fermented, obtaining the maximal VFA production for the 7.5 dose of cellobiose. Total VFA production for CEL was greater with LSF than with HSF inoculum (20.7 vs. 12.9 mmol/l; p = 0.014), but the opposite was found for WS (3.97 vs. 6.21 mmol/l; p = 0.005). The use of LSF inoculum for CEL fermentation sharply reduced acetate (p = 0.001) and increased butyrate proportions (p ≤ 0.001) compared with the HSF inoculum. A positive relationship between total VFA caecal concentrations in rabbits receiving the same experimental treatments and in vitro values was only observed when WS was used as substrate (r = 0.90; p = 0.015; n = 6). The results suggest that experimental factors influenced the fermentative activity of caecal digesta, but the observed response differed with the incubated substrate, being the CEL the most affected.     

Time course study of Bactrocera oleae (Diptera: Tephritidae) pupae predation in soil: the effect of landscape structure and soil condition

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873. ECHIUM NERVOSUM

The Madeiran endemic Echium nervosum W.T. Aiton is illustrated based on plants grown at the Royal Botanic Gardens, Kew. Its ecology; phylogenetic and taxonomic placement, and conservation status are discussed. Twenty‐nine species of Echium are endemic to the Macaronesian Islands and they represent one of the most spectacular and best known examples of adaptive radiation on oceanic islands.     

880. EUPHORBIA TUCKEYANA

Euphorbia tuckeyana is a dendroid spurge endemic to Cabo Verde. It belongs to E. subgenus Esula section Aphyllis subsection Macaronesicae, a monophyletic group of eleven species restricted to the Canaries, Madeira archipelago, the Selvagens islands, Cabo Verde, a small area of Atlantic Morocco, and Portugal, that have high horticultural potential for xeric gardens. Among them E. tuckeyana grows well in tropical environments with a summer rainy season. History of early collections and records is reviewed. The species has been previously depicted on one postage stamp and in papers focusing on the Cabo Verde flora. Three other phylogenetically distant groups of dendroid spurges, also with leaves spirally arranged in clusters located on stem tips, occur in the West Indies, Africa, and Asia. They also show high potential for tropical gardens. We present a previously unpublished ink‐drawing of E. tuckeyana that was made by the great Spanish plant illustrator Eugeni Sierra Ràfols (1919–1999). The name is lectotypified with a specimen housed in the Muséum National d'Histoire Naturelle (Paris) that was collected by the Portuguese naturalist João da Silva Feijó in the late 18th century.