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).     

Biocatalytic modification of polyethylene terephthalate fibres by esterases from actinomycete isolates

The modification of polyethylene terephthalate (PET) fibres by extracellular enzymes produced by actinomycetes was investigated. Cultivation of isolates in media containing PET yarn and suberin, a plant polyester composed of aliphatic and aromatic moieties, induced the production of p-nitrophenyl butyrate hydrolyzing enzymes. Incubation of enzyme preparations from the isolates M5, M9 and Thermomonospora fusca KW3b with PET yarn resulted in an increase in the absorbance of the reaction mixtures at 240 nm indicating the release of terephthalic acid or its esters catalyzed by the enzymes. The results of dyeing of enzyme-treated PET fabrics with a reactive dye (CI Reactive Red 2) indicated an increase in hydroxyl groups at the fibre surfaces as a result of the enzyme treatment.     

Bioaccumulation and elimination rate of cobalt in Capoeta fusca under controlled conditions

Abstract

The objective of the present study was to investigate the pattern of accumulation and elimination of cobalt in selected organs of Capoeta fusca, after chronic exposure. Samples of C. fusca were obtained from a qanat in Birjand between July and September 2010. Cobalt accumulation was studied in fish exposed to 6.8 mg L^-1 of cobalt for 15 days and the elimination was investigated in the contaminated fish samples placed in tap water for another 15 days. Using atomic absorption spectrophotometry it was found that the accumulation of cobalt in tissues was in the following order: liver>muscle>gill>skin. The elimination of cobalt was in the following order: skin>gill>muscle>liver. The bioaccumulation and elimination of cobalt were significant in the organs of C. fusca (P<0.01). The accumulation of cobalt in C. fusca was rapid and increased with an increase in metal concentration in water and the duration of exposure. The results of the present study showed that the accumulation and elimination of cobalt in C. fusca depend on the type of organs and the duration of exposure.     

Bacterial endophytes enhance phytostabilization in soils contaminated with uranium and lead

The combined use of plants and bacteria is a promising approach for the remediation of polluted soil. In the current study, the potential of bacterial endophytes in partnership with Leptochloa fusca (L.) Kunth was evaluated for the remediation of uranium (U)- and lead (Pb)-contaminated soil. L. fusca was vegetated in contaminated soil and inoculated with three different endophytic bacterial strains, Pantoea stewartii ASI11, Enterobacter sp. HU38, and Microbacterium arborescens HU33, individually as well as in combination. The results showed that the L. fusca can grow in the contaminated soil. Bacterial inoculation improved plant growth and phytoremediation capacity: this manifested in the form of a 22–51% increase in root length, 25–62% increase in shoot height, 10–21% increase in chlorophyll content, and 17–59% more plant biomass in U- and Pb-contaminated soils as compared to plants without bacterial inoculation. Although L. fusca plants showed potential to accumulate U and Pb in their root and shoot on their own, bacterial consortia further enhanced metal uptake capacity by 53–88% for U and 58–97% for Pb. Our results indicate that the combination of L. fusca and endophytic bacterial consortia can effectively be used for the phytostabilization of both U- and Pb-contaminated soils.     

Synthesis of cinnamyl acetate catalysed by highly reusable cotton-immobilized Pseudomonas fluorescens lipase

Cinnamyl acetate as an important fragrance ingredient could be synthesized by lipase-catalysed transesterification in organic systems, but enzyme proteins tended to denature and inactivate for no water lubrication. To improve the non-aqueous stability of lipases, absorbent cotton was taken as an alternative “water” phase to stabilize enzyme proteins. In a mass ratio of 1:1, Pseudomonas fluorescens lipase was immobilized on cotton fibres by physical absorption in a column glass bottle, forming a facile cotton-lipase bioreactor in which the transesterification between cinnamyl alcohol and vinyl acetate processed efficiently. From the molar conversions after reaction for 2?h at 37?°C and 160?rpm, the ability of cotton-lipase to transform substrate was more than 5-folds of native lipase. And even in static state and at 4?°C, the conversion of reaction catalysed by cotton-PFL had 11-fold increase relative to native lipase after 8?h. Recycles showed that the cotton-lipase had an extra-long half-life of activity (t_1/2?=?693?h) and a negligible decay rate in the ability to transform substrate (D_r?=?0.08% h^?1). All these showed that this lipase had been effectively activated and stabilized by cotton fibres for the numerous hydroxyl groups and fluffy structure.     

Variation in encapsulation sensitivity of Cotesia sesamiae biotypes to Busseola fusca

Many braconid wasp species inject polydnaviruses to overcome their host's immune system. In the species Cotesia sesamiae, two biotypes exist that differ in their ability to develop in the host Busseola fusca. The biotype from coastal Kenya is infected with Wolbachia and is not able to develop in larvae of B. fusca, whereas the uninfected inland biotype of this wasp can develop in B. fusca. The genetic transmission of the developmental ability was studied through a series of genetic crosses and superparasitization experiments. The Wolbachia infection of the coastal type did not play a role in the encapsulation response of the host. Experiments show that the polydnaviruses of the wasps could not prevent the encapsulation of the coastal parasitoid eggs. Most likely, larval characteristics such as surface proteins played a more important role in the encapsulation response of the host even in the presence of a functional polydnavirus.     

Variation in encapsulation sensitivity of Cotesia sesamiae biotypes to Busseola fusca

Many braconid wasp species inject polydnaviruses to overcome their host's immune system. In the species Cotesia sesamiae, two biotypes exist that differ in their ability to develop in the host Busseola fusca. The biotype from coastal Kenya is infected with Wolbachia and is not able to develop in larvae of B. fusca, whereas the uninfected inland biotype of this wasp can develop in B. fusca. The genetic transmission of the developmental ability was studied through a series of genetic crosses and superparasitization experiments. The Wolbachia infection of the coastal type did not play a role in the encapsulation response of the host. Experiments show that the polydnaviruses of the wasps could not prevent the encapsulation of the coastal parasitoid eggs. Most likely, larval characteristics such as surface proteins played a more important role in the encapsulation response of the host even in the presence of a functional polydnavirus.     

Life Cycles of Myxogastria Stemonitopsis typhina and Stemonitis fusca on Agar Culture

Myxogastria is a group of protozoa characterized by cellular uninucleate amoeboflagellates (myxamoebae and flagellated swarm cell), acellular multinucleate plasmodia, and stationary spore‐bearing sporocarps. The Stemonitales is a large order in the Myxogastria and contains approximately 230 species, but only 13 species have their completed life cycles observed so far. Here, we described the life cycles of two species in Stemonitales, Stemonitopsis typhina and Stemonitis fusca by culturing in water agar medium and observing the morphogenesis of their spore germination, plasmodium, and sporocarp development. The spore‐to‐spore life cycles of Ste. typhina and S. fusca were completed in approximately 67 and 12 d, respectively. Both species possessed an aphanoplasmodium. However, the spores of Ste. typhina and S. fusca germinated by the V‐shape split and pore methods, respectively. Unlike S. fusca with an evanescent peridium, Ste. typhina produced a shiny persistent peridium which was continuous with the membrane surrounding its stalk. The information will contribute to a better understanding of their taxonomy and phylogeny.     

Volume regulation in vitro of muscle fibres of the crab,Hemigrapsus edwardsi

Summary Isolated flexor muscles of the shore crab,Hemigrapsus edwardsi were maintained in saline solutions for periods of 2–12 h.In hypotonic saline solutions containing less than 400 mM sodium chloride, the fibres rapidly died. In 400 mM sodium chloride saline the fibres showed partial volume readjustment associated with reduction in the amount of intracellular ninhydrin-positive substances (NPS).In saline (460 mM sodium chloride) containing ouabain (2–5 mM) the fibres lost water and potassium, gained sodium and chloride, but the amount of NPS was not significantly changed.In hypertonic saline (550 mM sodium chloride) the fibres showed a partial recovery of volume during the 8 h experimental period. Associated with this was a rise in the amount of intracellular NPS.It was concluded that the ability of the muscle fibres ofHemigrapsus edwardsi to respond to a hyperosmotic challenge in an amino acid free medium, by an increase in intracellular amino acid levels, must represent a synthesis of these compounds from an intracellular source. This may be an adaptive feature of osmotic readjustment in this rather permeable crab.     

Duration of diapause in the stem borers, Busseola fusca and Chilo partellus

The duration of diapause in the stem borers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) was studied in South Africa by collecting diapausing larvae from the field throughout winter (April–August). B. fusca larvae emerged as moth around the middle of October regardless of the date of collection and the length of time they were kept in the laboratory under constant 21 °C. C. partellus larvae collected in April–June emerged in November, those collected in July emerged in October, and those collected in August emerged in September. Regardless of the collection date C. partellus started to emerge from diapause earlier and moth emergence lasted up to twice as long as in B. fusca. Under laboratory conditions at 60% RH both borer larvae lost about 50% of their body mass during diapause. When provided with water B. fusca larvae lost about 30% of their body mass and adults emerged 20 days earlier than when kept dry. C. partellus, on the other hand, lost only 13% of their body weight and emerged 34 days earlier. The differences between the two species are discussed in light of different types of diapause; i.e., obligatory diapause in B. fusca and facultative diapause in C. partellus.     

Messenger RNA for isocitrate lyase from Chlorella fusca var. vacuolata

Chlorella fusca cultures growing in the light and adapting to acetate in the dark were labelled with adenine-³H and adenine-¹⁴C, respectively. Poly(A)-containing RNA from the mixed cultures was analysed for ¹⁴C/³H ratio after polyacrylamide gel electrophoresis in 98% formamide. The RNA from acetateadapting C. fusca cells contained excess label migrating in the gels at a position equivalent to about 0.85×10⁶ mol.wt. Partially purified anti-isocitrate lyase serum linked to p-aminobenzoyl-cellulose bound 3.5–13% of polysomes from acetate-adapting C. fusca, containing 5–10% of polysomal poly(A)-containing RNA. The antibody-bound poly(A)-containing RNA fraction showed a unimodal size distribution with a mean size of about 0.85×10⁶ mol.wt. after electrophoresis on 4% polyacrylamide gels in 98% formamide. Cell-free translation assays showed a three-fold enrichment of isocitrate lyase mRNA after antibody selection of polysomes and indicated that isocitrate lyase mRNA was abundant in acetate-adapting C. fusca cells.Abbreviations A ₂₆₀ unit The amount of material in 1.0 ml giving an absorbance of 1.0 at 260 nm in a 1 cm light path - PAB-cellulose p-aminobenzoyl-cellulose - SDS sodium lauryl sulphate To whom offprint requests are to be sent     

Pine pollen dehiscence relative to thrips population dynamics

A two‐part study related tree pollen dehiscence and thrips population dynamics in the field, and directly evaluated effects of pine pollen deposition on Frankliniella spp. (Thysanoptera: Thripidae) reproduction on tobacco, Nicotiana tabacum L. (Solanaceae), under laboratory conditions. Ambient pollen and thrips were monitored in Tift County, GA, USA, from early spring to late summer/early fall from 2005 to 2008. Correlation analyses were conducted using weekly means of thrips collected on sticky traps compared to weekly pollen counts from a Burkard air sampler and pollen deposition sheets. There were significant positive correlations between pollen and thrips counts on later dates, suggesting that if a relationship exists between pine pollen dehiscence and thrips population dynamics, it will be delayed. Over all years combined, the first spring time peak in Frankliniella fusca (Hinds) counts on sticky traps occurred at 227 accumulated degree days (dd) after the first peak in pine pollen, approximately the dd required to complete a single F. fusca generation. Two subsequent thrips peaks occurred at approximately one and two F. fusca generations following the first peak. After 10 weeks following the final peak in pollen, there appears to be no more effect of pollen on thrips population dynamics. A tobacco leaf, lightly dusted with Slash pine [Pinus elliottii Engelmann (Pinaceae)] pollen to mimic natural deposition, showed a significant increase in the number of offspring produced per Frankliniella occidentalis (Pergande) and F. fusca female. The total offspring produced increased five‐fold in F. fusca and 22‐fold in F. occidentalis in 15 days on the pollen‐treated leaves over the untreated leaves.     

Direct and indirect effects of a thrips‐transmitted Tospovirus on the preference and fitness of its vector,Frankliniella fusca

Phytoviruses including tospoviruses are known to affect the behavior and fitness of their vectors both positively and negatively. In this study, we investigated the effects of Tomato spotted wilt virus (TSWV) (family Bunyaviridae, genus Tospovirus) infection on the fitness and feeding ability of tobacco thrips, Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) using peanut, Arachis hypogaea L. (Fabaceae), as a host. Potentially viruliferous F. fusca laid more eggs than non‐viruliferous F. fusca. In contrast, fewer potentially viruliferous F. fusca developed into adults and required a longer developmental time than non‐viruliferous F. fusca, indicating a direct negative effect of the virus on thrips fitness. In addition, no‐choice feeding tests indicated that non‐viruliferous F. fusca fed more rapidly than potentially viruliferous F. fusca. Typically, phytovirus infections are known to enhance the availability of vital nutrients such as free amino acids in infected host plants and to affect other important physiological processes negatively. Free amino acids are known to play a vital role in egg production and development. Further investigations in this study revealed that leaflets of infected plants had ca. 15 times more free amino acids than non‐infected leaflets. TSWV‐infected leaflets were used to rear potentially viruliferous thrips. Higher amino acid levels in TSWV‐infected leaflets than in non‐infected leaflets could have contributed to increased oviposition by potentially viruliferous F. fusca compared to non‐viruliferous F. fusca. Taken together, these results suggest that increased concentrations of free amino acids in TSWV‐infected plants might serve as an incentive for thrips feeding on otherwise unsuitable hosts, thereby facilitating TSWV acquisition and transmission.     

Flight and oviposition behaviour of the African stem borer,Busseola fusca,on various host plant species

The African stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae), is an important pest of maize and sorghum in sub‐Saharan Africa. As in many other lepidopteran insects, the ability of B. fusca to recognize and colonize a variety of plants is based on the interaction between its sensory systems and the physical and chemical characteristics of its immediate environment. In this study, we tried to identify the behavioural steps of B. fusca leading to host selection and oviposition. Three Poaceae species commonly cultivated in Kenya for human consumption and animal forage were used in this study: the two most preferred hosts, maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench], and one non‐preferred host, Napier grass (Pennisetum purpureum Schumach). Wind tunnel observations revealed that volatiles produced by the different plant species did not appear to strongly influence the general orientation of B. fusca towards the plant, as similar behavioural steps were exhibited by the female moth regardless of the plant species involved. This indicated that the females were not able to recognize their preferred hosts from a distance. After landing, the female typically swept her ovipositor on the plant surface, simultaneously touching it with the tips of her antennae, and then oviposited. This behaviour was more frequently observed on maize and sorghum than on Napier grass, and indicated that both antennal and ovipositor receptors are used by the female moths to evaluate the plant surface before deciding to oviposit. As a result, the females laid more eggs on the two crops than on Napier grass. We conclude therefore that females recognized their preferred hosts only after landing. Tactile and contact‐chemoreception stimuli from the plants seemed to play a major role in oviposition decisions of B. fusca.     

Metabolic engineering of a laboratory‐evolved Thermobifida fusca muC strain for malic acid production on cellulose and minimal treated lignocellulosic biomass

Malic acid is mainly used as an acidulant and taste enhancer in the beverage and food industry. Previously, a mutant strain Thermobifida fusca muC, obtained by adaptive evolution was found to accumulate malic acid on cellulose with low yield. In this study, the malic acid synthesis pathway in T. fusca muC was confirmed to be from phosphoenolpyruvate to oxaloacetate, followed by reduction of oxaloacetate to malate. To increase the yield of malic acid by the muC strain significantly, the carbon flux from pyruvate was redirected to oxaloacetate by expressing an exogenous pyruvate carboxylase (PCx) gene from Corynebacterium glutamicum ATCC 13032 in the chromosome of T. fusca muC‐16. The yield of malic acid in the engineered strain muC‐16 was increased by 47.9% compared to the parent strain muC. The muC‐16 strain was then grown on ～100 g/L cellulose and the highest titer of malic acid was 62.76 g/L by batch fermentation. T. fusca muC‐16 strain converted milled corn stover to malic acid with the highest titer of 21.47 g/L with minimal treatment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:14–20, 2016     

Dissemination of entomopathogenic fungi using Busseola fusca male as vector

The stem borer, Busseola fusca (Fuller), is an important pest of maize Zea mays L. and sorghum Sorghum bicolor (L.) in eastern and southern Africa. To control this pest, biological control methods including the use of entomopathogenic fungi are being considered. The pathogenicity of one isolate of Metarhizium anisopliae (Metsch.) Sorok. and one isolate of Beauveria bassiana Bals. (Vuill.) were first tested on different developmental stages of B. fusca including eggs, neonate, 2nd and 3rd-instar larvae. Both fungal isolates were pathogenic to all the stages tested. However, differences in mortality were observed among larvae that hatched from treated egg masses. Experiments were conducted thereafter to test whether B. fusca males could serve as a vector for fungal conidia to contaminate B. fusca females and subsequently eggs and larvae. Results demonstrated that B. fusca males successfully transferred inoculum to females during copulation, which in turn transmitted it to the eggs they laid on maize plants, resulting in the decrease of leaf damages.     

Membrane stabilization and survival of dehydratedChlorella fusca cells induced by calcium

Chlorella fusca was subjected to evaporative dehydration under air humidity of 72%. Ca²⁺ pretreated cultures lost water as rapidly as untreated cultures. Nevertheless, an ameliorative effect of Ca²⁺ pretreatment in droughted cells was found as membrane stability index was improved and K⁺ leakage was reduced. In addition, higher chlorophyll content and stability was observed. These parameters enabled droughted cells to recommence growth upon rewatering. Thus Ca²⁺ might increase survival ofC. fusca cells subjected to drought through membrane stabilization.     

An inducible release of reactive oxygen radicals in four species of gorgonian corals

The capability for physical injury or heat stress to elicit the production of reactive oxygen species was examined in four species of gorgonian corals. The sea plumes Pseudopterogorgia elisabethae, Pseudopterogorgia americana, the sea rod Eunicea fusca and the azooxanthellate red branching gorgonian Lophogorgia chilensis were physically injured using sonic sound cavitations and heat shocked by incubation in 33°C sea water. The pharmacological probe, diphenylene iodonium chloride (DPI), an inhibitor of NAD(P)H oxidase and peroxidases was used to identify an enzymatic surrogate of the oxidative burst. Both injury and heat stress were capable of inducing the release of reactive oxygen species (ROS) in all gorgonians tested, yet the kinetics and amplitude of ROS release varied among genera. In both the treatments, P. americana demonstrated the largest oxidative burst among the other corals tested.     

Behaviour of Bacterial Populations Isolated from Rhizosphere of Diplachne fusca Dominant in Industrial Sites

Summary A total of 107 bacterial strains were isolated from rhizosphere soil of Diplachne fusca naturally grown in industrial metal-contaminated soils. All the isolates were examined for their ability to tolerate Cd²⁺, Cr³⁺, Co²⁺, Cu²⁺, Pb²⁺, Ni²⁺ and Zn²⁺ in their growth medium, in addition, three related phenotypic characters, the ability to produce acids and siderophores and/or calcium phosphate solubilization, were tested. The resistance patterns, expressed as MICs, for all bacterial isolates to seven different metal ions were surveyed by using the agar dilution method. A great proportion of the isolates were resistant to Cr (99%), Pb (93%), Cu (87%) and Zn (86%). On the other hand, 77, 49 and 45% were sensitive to Co, Ni and Cd, respectively. The majority of the strains tested (98%) were multiple metal-resistant, with hexametal resistance as the major pattern (24.2%). The increase in metal ion uptake (especially Cr, Pb, Zn and Ni) by D. fusca was correlated with higher numbers of siderophore-producing, phosphate-solubilizing and acid-producing bacteria 95, 81 and 64%, respectively.