Fragmentation of cellulose by the major Thermomonospora fusca cellulases, Trichoderma reesei CBHI, and their mixtures

In this study, the fragmentation activities of Thermomonospora fusca cellulases E(2), E(3), E(5), Trichoderma reesei CBHI, and their mixtures were measured to study synergism in fragmentation. Fragmentation studies revealed that only two pure cellulases, T. fusca E(2) and E(5) had significant fragmentation activity. T. fusca E(3) shows strong synergism in fragmentation both in the production of reducing sugars and in fragmentation with both T. fusca endoglucananses and with T. reesei CBHI. Most mixtures containing CBHI produced higher rates of fragmentation than comparable mixtures containing E(3). The highest rate and extent of reducing sugar formation and the highest fragmentation activity were obtained with a mixture of E(2), E(3), and CBHI. (c) 1992 John Wiley & Sons, Inc.     

Adaptation of the Photosynthetic Apparatus of Chlorella and Ankistrodesmus to Blue and Red Light

The mode of adaptation of the photosynthetic apparatus of three unicellular green algae, Ankistrodesmus braunii, Chlorella fusca and Chlorella saccharophila to red and blue light are documented by the fluence-rate curves of photosynthetic oxygen evolution. For all three algae tested photosynthetic capacity, respiration and light compensation point were higher for cells grown under red light, while the chlorophyll content increased in blue light-grown cells. Blue light-adapted cells have a lower chlorophyll a to chlorophyll b ratio and more chlorophyll in the light-harvesting system than red light-adapted cells, as shown in the electrophoretic profile of the pigment-protein complexes. It is concluded that the action of red light resembles that of high levels of white light, while blue light causes the same effects as low levels of white light. In agreement with previous publications these findings indicate that the mode of adaptation to different light qualities is ubiquitous in unicellular green algae.     

Grooming in brown howler monkeys,Alouatta fusca

The grooming behavior of a group of brown howler monkeys was studied for one year in an Atlantic forest reserve of southeastern Brazil. A total of 290 grooming bouts were recorded and analyzed. The two adult females directed most of the grooming (91%), while the adult male was the major recipient (37%). Grooming between females, and between them and their siblings, also occurred quite often. On average, the group spent 2% of its daily time grooming, with a higher frequency around noon. There were significant differences, however, in time spent grooming between seasons; grooming was more abundant during the coldest seasons (autumn–winter) and rarer in hotter ones (spring–summer). A significant negative correlation was found between grooming time and temperature, but contrary to expectations, grooming time failed to correlate with both the group' diet and the demands of food-gathering, as measured by travelling time and day range length. A comparison of grooming behavior with other species of the genus suggests that brown, red (A. seniculus), and black howler monkeys (A. caraya) are more similar to each other than to mantled howlers (A. palliata), a result that probably is linked with the differing social structure and group size of the latter species. © 1995 Wiley-Liss, Inc.     

Co-operative actions and degradation analysis of purified xylan-degrading enzymes from Thermomonospora fusca BD25 on oat-spelt xylan

AIMS: To determine and quantify the products from the degradation of xylan by a range of purified xylan-degrading enzymes, endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase produced extracellularly by Thermomonospora fusca BD25. METHODS AND RESULTS: The amounts of reducing sugars released from oat-spelt xylan by the actions of endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase were equal to 28.1, 4.6 and 7% hydrolysis (as xylose equivalents) of the substrate used, respectively. However, addition of beta-xylosidase and alpha-l-arabinofuranosidase preparation to endoxylanase significantly enhanced (70 and 20% respectively) the action of endoxylanase on the substrate. The combination of purified endoxylanase, beta-xylosidase and alpha-l-arabinofuranosidase preparations produced a greater sugar yield (58.6% hydrolysis) and enhanced the total reducing sugar yield by around 50%. The main xylooligosaccharide products released using the action of endoxylanase alone on oat-spelt xylan were identified as xylobiose and xylopentose. alpha-l-Arabinofuranosidase was able to release arabinose and xylobiose from oat-spelt xylan. In the presence of all three purified enzymes the hydrolysis products of oat-spelt xylan were mainly xylose, arabinose and substituted xylotetrose with lesser amount of substituted xylotriose. CONCLUSIONS: The addition of the beta-xylosidase and alpha-l-arabinofuranosidase enzymes to purified xylanases more than doubled the degradation of xylan from 28 to 58% of the total substrate with xylose and arabinose being the major sugars produced. SIGNIFICANCE AND IMPACT OF THE STUDY: The results highlight the role of xylan de-branching enzymes in the degradation of xylan and suggest that the use of enzyme cocktails may significantly improve the hydrolysis of xylan in industrial processes.     

PHYLOGENETIC AND TAXONOMIC POSITION OF LEPOCINCLIS FUSCA COMB. NOV. (=EUGLENA FUSCA) (EUGLENACEAE): MORPHOLOGICAL AND MOLECULAR JUSTIFICATION1

We studied the morphological diversity and analyzed the small subunit rDNA sequences of two taxa formerly known as Euglena spirogyra Ehr. and Euglena fusca (Klebs) Lemmermann. Our studies confirmed that the two should have the rank of a species, namely Lepocinclis spirogyroides (Ehr.) Marin et Melkonian and Lepocinclis fusca (Klebs) Kosmala et Zakry? comb. nov. (Euglenophyceae). We are defining new diagnostic features for these species, namely the size and the shape of the cells and the shape of the papillae, as well as designating epitypes for them.     

Worker reproduction in the ant Formica fusca

We studied the kin conflict over male parentage in the ant Formica fusca. The conflict arises because each worker and queen is most related to her own sons and is thus predicted to lay eggs. Microsatellite analysis of eggs revealed that workers laid eggs in more than half the queenright experimental nests. Nevertheless, almost exclusively diploid offspring were reared in the presence of a queen. This also occurred when worker-laid haploid male eggs were experimentally introduced in to the nests. Because our experimental setup allowed us to exclude the possibility of queen policing, we conclude that worker laid eggs are removed by other workers, either as a response to their parentage or gender. Our results suggest that worker reproduction in F. fusca is ultimately an interplay of conflicts over male parentage and sex allocation and that both worker and self policing have roles as proximate mechanisms of resolution.     

Biocatalytic surface modification of knitted fabrics made of poly (ethylene terephthalate) with hydrolytic enzymes from Thermobifida fusca KW3b

Knitted fabrics made from poly(ethylene terephthalate) fibres were treated with an enzyme preparation from Thermobifida fusca KW3b showing hydrolytic activity on p-nitrophenyl butyrate. The fabrics were also treated with NaOH and the results were compared. Both enzyme- and alkaline-treated fabrics showed an increase in reactive dye uptake, vertical wicking height and water absorption capacity of the fabrics indicating an increased surface hydrophilicity. However, X-ray photoelectron (XPS) and energy-dispersive spectroscopy (EDS) did not give conclusive results on the presence of newly introduced hydrophilic groups on the surface of the fibres. Analysis of the enzyme-treated poly(ethylene terephthalate) fibres by scanning electron microscopy (SEM) and by atomic force microscopy (AFM) indicated an increase in surface roughness of the fibres, which may contribute to the observed increased hydrophilicity of the PET fabrics. However, much longer treatment times (24 h) were required to obtain these effects with the enzymes compared to the chemical treatment (1 h).     

Thermobifida fusca cellulases exhibit limited surface diffusion on bacterial micro‐crystalline cellulose

Elucidation of cellulase–cellulose interactions is key to modeling biomass deconstruction and in understanding the processes that lead to cellulase inactivation. Here, fluorescence recovery after photobleaching and single molecule tracking (SMT) experiments are used to assess the surface diffusion of Thermobifida fusca cellulases on bacterial micro‐crystalline cellulose. Our results show that cellulases exhibit limited surface diffusion when bound to crystalline cellulose and that a large fraction of the cellulases remain immobile even at temperatures optimal for catalysis. A comparison of our experimental results to Monte Carlo (MC) simulations, which use published diffusion coefficients to model cellulase displacements, shows that even those enzymes that are mobile on the cellulose surface exhibit significantly slower diffusive motions than previously reported. In addition, it is observed that the enzymes that show significant displacements exhibit complex, non‐steady surface motions, which suggest that cellulose–bound cellulases exist in molecular states with different diffusive characteristics. These results challenge the notion that cellulases can freely diffuse over cellulose surfaces without catalyzing bond cleavage. Biotechnol. Bioeng. 2013; 110: 47–56. © 2012 Wiley Periodicals, Inc.     

The effect of grassy field margins and fertilizer on soil water,plant nutrient levels,stem borer attacks and yield of maize in the humid forest zone of Cameroon

Two field experiments, planted in a split plot design, were conducted during 2002 in the forest zone of Cameroon, to investigate the effect of border rows with Pennisetum purpureum (Poaceae) or with Panicum maximum (Poaceae) on soil water, plant nitrogen (N), phosphorus (P) and potassium (K), borer infestations, parasitism and maize yield. The grassy boundaries were the main plots and fertilizer treatment the sub plots. Soil humidity was significantly higher under the grass borders than in maize plots. Nitrogen uptake by maize tended to be highest in plots surrounded by P. purpureum but the differences were significant during the second season only. Busseola fusca (Fuller) (Lepidoptera: Noctuidae) was the predominant borer species followed by Eldana saccharina (Walker) (Lepidoptera: Pyralidae). The predominant parasitoid species was the scelionid egg parasitoid Telenomus busseolae Gahan (Hymenoptera: Scelionidae). During both seasons, plant nitrogen, B. fusca infestation, plant damage and yield were significantly higher in maize sub-plots that received fertilizer The interaction between the grassy margin effect and the fertilization was significant only for B. fusca infestations, during the second season with maize + P. purpureum having a significantly lower number of borers in the fertilized than the unfertilized sub-plots. The grassy borders had no effect on B. fusca egg parasitism variables except in the first season, when maize with P. purpureum had a significantly higher percentage of egg batches parasitized. During both seasons, there were some significant differences in yield variables between main plots but the trends were not clear. Multiple regression showed that B. fusca infestation, plant damage, egg parasitism, plant N, P and K affected yield, with plant nutrients explaining most of the variability. The implication of the findings for the feasibilty of this habitat management technology to farmers in southern Cameroon is discussed.