Use of Ascomycete Extracts in Enzymatic Cocktail Formulations Increases Sugar Cane Bagasse Hydrolysis

Hemicellulases and accessory enzymes are essential for supplementation of cellulolytic enzyme extracts, and combinations of these enzymes can lead to high performance in plant biomass hydrolysis. In this work, enzyme extracts rich in hemicellulases and β-glucosidase, produced by the unique ascomycete strains Annulohypoxylon stygium DR47 and Aspergillus niger DR02, were tested for use in formulations with Celluclast 1.5 L. Statistical analysis showed that a mixture based on these enzymes was able to increase the hydrolysis of hydrothermally pretreated sugar cane bagasse. The two A. stygium extracts only effectively increased glucose release when they were combined. These extracts had no positive effect when used together with the A. niger extract, and the findings suggested that a blend based on the commercial cellulose preparation and the xylanase-rich extract from A. niger provided the best carbohydrate solubilization. Supplementation at low cellulolytic loading resulted in 120 and 238 % increases in cellulose and hemicellulose hydrolysis yields.     

Rheological changes of Aspergillus awamori broth during amyloglucosidase production

Two kinds of mathematical correlations are proposed, one between the biomass concentration and the rheological parameter consistency index (K) from the 'Power law' and another between either the specific growth rate or the specific glucoamylase production rate and K. Experimental data from Aspergillus awamori batch cultivations, with initial polysaccharide concentrations in the range of 20 to 180 g.L, were used to define these correlations.     

ARABIDILLO proteins have a novel and conserved domain structure important for the regulation of their stability

ARABIDILLO proteins are F-box-Armadillo (ARM) proteins that regulate root branching in Arabidopsis. Many F-box proteins in plants, yeast and mammals are unstable. In plants, the mechanism for this instability has not been fully investigated. Here, we show that a conserved family of plant ARABIDILLO-related proteins has a unique domain structure consisting of an F-box and leucine-rich repeats (LRRs) followed by ARM-repeats. The LRRs are similar to those found in other plant and animal F-box proteins, including cell cycle proteins and hormone receptors. We demonstrate that the LRRs are required for ARABIDILLO1 function in vivo. ARABIDILLO1 protein is unstable: we show that ARABIDILLO1 protein is associated with ubiquitin and is turned over by the proteasome. Both the F-box and LRR regions of ARABIDILLO1 appear to enable this turnover to occur. Application of known lateral root-regulating signals has no effect on ARABIDILLO1 stability. In addition, plants that lack or overexpress ARABIDILLO proteins respond normally to known lateral root-regulating signals. Thus, we suggest that the signal(s) regulating ARABIDILLO stability in vivo may be either highly specific or novel. The structural conservation between ARABIDILLOs and other plant and animal F-box proteins suggests that the stability of other F-box proteins may be controlled by similar mechanisms.     

Detection of Schistosoma mansoni eggs in feces through their interaction with paramagnetic beads in a magnetic field

Background

Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because often control measures have reduced egg burdens in feces to below the detection limits of classical coproparasitological methods. Evaluation of molecular methods is hindered by the absence of an established standard with maximum sensitivity and specificity. One strategy to optimize method performance, where eggs are rare events, is to examine large amounts of feces. A novel diagnostic method for isolation of Schistosoma mansoni eggs in feces, and an initial evaluation of its performance is reported here.

Methodology/Principal Findings

Known amounts of S. mansoni eggs were seeded into 30 g of normal human feces and subjected to a sequence of spontaneous sedimentation, sieving, Ritchie method, incubation and isolation through interaction with paramagnetic beads. Preliminary tests demonstrated the efficacy of lectins as ligands, but they also indicated that the paramagnetic beads alone were sufficient to isolate the eggs under a magnetic field through an unknown mechanism. Eggs were identified by microscopic inspection, with a sensitivity of 100% at 1.3 eggs per gram of feces (epg). Sensitivity gradually decreased to 25% at a concentration of 0.1 epg. In a preliminary application of the new method to the investigation of a recently established focus in southern Brazil, approximately 3 times more eggs were detected than with the thick-smear Kato-Katz method.

Conclusions/Significance

The novel S. mansoni detection method may significantly improve diagnosis of infections with low burdens in areas of recent introduction of the parasite, areas under successful control of transmission, or in infected travelers. It may also improve the evaluation of new treatments and vaccines.     

Fructans in callus of Gomphrena macrocephala St.-Hil.

The production of fructose-containing carbohydrates by leaf and node callus of Gomphrena macrocephala St.-Hil. grown in three different auxin to cytokinin ratios is described. The amount of these carbohydrates in node callus rose with increasing -naphthalene acetic acid to 6-benzylaminopurine ratios, while in leaf callus it tended to decrease. An homologous series of fructans was detected only in callus grown in 1:2 auxin to cytokinin ratio. These fructans were of the inulin series in contrast to the phlein series present in the tuberous root of intact plants. Fructose polymers were also detected in culture medium and these made up approximately 98% of the total fructopolysaccharides produced. The mean molecular weight of these polymers (40 kDa) was 3 times greater than that of fructan from intact plants. The fructo-polysaccharide pool could be a reflection of different physiological processes taking place in the callus rather than a direct effect of growth regulator treatment.Abbreviations BA-6 benzylaminopurine - DP degree of polymerization - high-MW high molecular weight - HPAEC/PAD high performance anion-exchange chromatography with pulsed amperometric detection - low-MW low molecular weight - MS Murashige and Skoog - NAA -naphthalene acetic acid - TFA trifluoroacetic acid - TLC thin layer chromatography     

The ultrastructure and innervation of muscles controlling chromatophore expansion in the squid,Loligo vulgaris

Squid chromatophores are organs of colour change, consisting of a pigment sac opened by contraction of 10–24 radial muscle fibres. The ultrastructure and innervation of these muscle fibres were examined by electron microscopy and diagramatic reconstructions made on the basis of serial ultra-thin sections. At the proximal end of the fibre, nearest the pigment sac a cortical myofilament zone surrounds 2 cores containing mitochrondria; further along the fibre these merge to form one central core. The myofilament zone forms a groove containing a nerve bundle consisting of 2 to 4 axons per muscle fibre. The axons are surrounded by glial cell processes, and either originate from a neighbouring fibre, or join the fibre at some point along its length. Axons twist around each other, forming a series of synapses with the muscle fibre. As many as 6–37 synapses exist along the length of each muscle fibre; the mean synapse interval is 9.05 m, but the largest may be 123 m. At the distal end of the muscles, the nerve is located towards the middle of the fibre, which it penetrates as the muscle splits up. Electron-lucent vesicles are present in all synaptic regions, but electron-dense vesicles are only found towards the distal end of the fibre. There is thus a possibility that more than one neurotransmitter is present in the nerves innervating chromatophores. Electron-lucent and dense-cored vesicles are not colocalised.This work was carried out during the tenure of a BBSRC CASE studentship     

Socio-maternal behaviors in response to an infant birth inColobus guereza

A number of social behaviors were observed in a captive troop ofColobus guereza on a regular basis for eight months. These included clasping and related behaviors, forward mounts, rear mounts, presents, troop positions during rest periods, infant transfers and attempted transfers, play, and grooming. During the observation period two significant events occurred: a re-introduction of a mother and her juvenile female, and the birth of an infant to a resident female. These events caused an increase in certain adult behaviors indicating a relationship of them with similar behaviors done between mothers and infants. This similarity seemed to indicate the co-evolution of “maternal” behaviors for use in adult social interactions and the phenomenon of infant transfer or sharing. The maternal and socio-maternal behaviors and their infantile precursors are then discussed in relation to the ontogeny of behavioral forms, the ontogeny of motivation in such behaviors, and the idea of infantile regression during development and in adult life.