Factors Affecting the Cellulolytic Activity of Rumen Contents

The cellulolytic activity of rumen contents was assayed by measuring losses in weight and tensile strength of cotton yarn incubated in rumen contents in the presence of dietary additives (barley, tallow) and at different pH values. The addition of barley depressed cellulolysis and the titer of filter paper-degrading bacteria only if the pH was allowed to fall. Lowering the pH from 7.0 to 6.0 by addition of HCl almost completely inhibited attack of cotton and greatly reduced the titer of filter paper-degrading bacteria. The layering of tallow on cotton inhibited attack of cotton but did not decrease the titer of filter paper-degrading bacteria. The results are discussed with special reference to the importance of the study of cellulosic substrates, which require a known enzyme or mixture of enzymes for attack.     

Action of purified Trichoderma reesei cellulases on cotton fibers and yarn

In this work the possibility and potential of treating cotton fibers and yarns instead of fabrics with monocomponent cellulases was investigated. Different pretreatments on fibers were performed and tested in order to improve the accessibility of cotton to enzymatic modification. The enzymatic treatments were evaluated microscopically and by analysing the effects of treated fibers on spinnability, yarn evenness, tenacity and pilling. The accessibility of the cotton fibers for cellulases could be increased by different pretreatments. Steaming of fibers prior to enzymatic treatment was found to be an efficient way to increase hydrolysis levels. Cellulase treatments of carded yarns resulted in modification of yarn properties. Decrease in yarn hairiness was observed and the knitted fabric made of the treated yarn showed a lowered tendency towards pilling. In all cases endoglucanase activity rather than cellobiohydrolase activity was responsible for these modifications.     

Could the recycled yarns substitute for the virgin cotton yarns: a comparative LCA

Purpose

Cotton yarns spun from natural fibers are widely used in the apparel industry. Most of waste cotton goods are now disposed by incineration or landfill, which brings resource and environmental challenges to the society. Using the waste cotton to spin yarns is an alternative way to forward a more sustainable future. In this research, two scenarios for the environmental impacts of yarns spun from corresponding fibers are investigated, including recycled cotton fibers and virgin cotton fibers.

Methods

The life cycle assessment (LCA) has been conducted according to the collected data from on-site investigation of typical production factories. The life cycle for the recycled cotton yarn production is divided into five stages, i.e., raw material acquisition, transportation, breaking, mixing, and spinning. The life cycle of virgin cotton yarn production is been divided into four stages, i.e., raw material acquisition, transportation, mixing, and spinning. The functional unit is 1000 kg produced yarns which are used for weaving into the fabrics. Notable impacts on climate change, fossil depletion, water depletion, and human toxicity were observed.

Results

The life cycle impact assessment (LCIA) results show that environmental impacts of recycled cotton yarns are far less than those of virgin cotton yarns, except for climate change and water depletion. The reason is that the land occupation and irrigation water have great impact on environmental impacts of cotton cultivation. In spinning, the electricity is the key factor whose environmental impacts account for the most in the virgin cotton yarn scenario, while the electricity and water consumptions are the key factors for the recycled cotton yarn scenario in the life cycle of yarn production. The sensitivity analysis indicates that improving energy efficiency can significantly reduce environmental burdens for both the two scenarios. The uncertainty distribution of water depletion, human toxicity, fossil depletion, and climate change of the two scenarios were determined with a 90% confidence interval.

Conclusions

The LCIA results reveal recycled cotton yarn is a viable alternative to relieve resource and environmental pressure. About 0.5 ha of agricultural land can be saved, 6600 kg CO₂ eq can be reduced, and 2783 m³ irrigation water can be saved by using 1000 kg of the recycled cotton yarns. It can be concluded that the recycled cotton fibers can be served as a substitute for virgin cotton fibers to reduce agricultural land and avoid environmental impacts generated from the cotton planting.

     

烟草几丁酶β—1.3—葡聚糖酶的抑菌作用

从三个方面对激发子诱导烟草几丁质酶,β－１．３－葡聚糖酶的病理功能进行了测定,结果表明：①两种酶对赤星菌的菌落生长有抑制作用并可抑制孢子萌发,对其它被测病原物抑制作用非常微弱;②两种酶对赤星菌等有明显的攻击作用,直接攻击抱子的反应在３０ｍｉｎ内可见,到１６ｈ前后引起孢子破裂;③扫描电镜观察,酶对寄主生活叶面上的赤星菌有同样攻击作用。     

The dietary relationships of Tribolium castaneum (Herbst) with microfungi

The ecology of Tribolium castaneum (Herbst) outside of grain storage facilities is poorly known. However, high densities of T. castaneum adults are known to infest stored cotton seeds (Gossypium hirsutum (L.)) in Queensland, Australia, despite the absence of stored food products in the immediate vicinity. Previous studies suggest that the beetles are attracted to the fungal colonies growing on the residual fibres that remain on the cotton seeds after ginning, but the specifics of this remain unclear, even as to the species of fungi involved. In the current study, 14 fungal species were isolated from stored cotton seeds collected from four sites in Queensland. The feeding preferences of the adult beetles and the developmental success of the larvae were recorded for each fungal species. Gut analyses of T. castaneum adults, after exposure in no-choice feeding tests, showed that the beetles will feed on any one of the 14 fungal species when exposed (over 14 days) to cotton seeds that had been inoculated with one particular fungal species. The developmental success of the larvae varied depending on the fungal species, with most fungal species supporting only low levels of successful development (<30%). Tests with each fungal species and the volatiles they release revealed that neither adult nor larval survival was significantly affected by the presence of any particular fungal isolate. These results indicate that T. castaneum will feed on a variety of fungal species but that none of the tested fungal species on its own provides a good larval diet for T. castaneum.     

Rechargeable biocidal cellulose: Synthesis and application of 3-(2,3-dihydroxypropyl)-5,5-dimethylimidazolidine-2,4-dione

An N-halamine precursor containing two hydroxyl groups (diol) has been synthesized. The N-halamine diol precursor was coated onto cotton fabrics with the assistance of the cross-linking agent BTCA. The surface of the coated cotton could be rendered biocidal by exposure to dilute hypochlorite solutions. Syntheses routes, characterization data, and antimicrobial test results will be presented. The durability and rechargeability of chlorine on the coated cotton was determined according to an AATCC standard washing test. The chlorinated cotton swatches were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895) and showed excellent efficacy against these two bacterial species within a brief time of contact. Over 70% of the chlorine lost after repeated washing or UVA irradiation could be regained upon rechlorination.     

Large‐Scale Conductive Yarns Based on Twistable Korean Traditional Paper (Hanji) for Supercapacitor Applications: Toward High‐Performance Paper Supercapacitors

A simple and scalable method to fabricate a yarn‐type supercapacitor with a large specific capacitance without the aid of traditional pseudocapacitive electrode materials such as conducting polymers and metal oxides is reported. The yarn‐type supercapacitors are made from twisting reduced graphene oxide (rGO) or/and single‐walled carbon nanotubes (SWNTs)‐coated Korean traditional paper (KTP). The yarn‐type paper supercapacitor displays surprisingly enhanced electrochemical capacitance values, showing synergistic effect between rGO and SWNTs (500 times larger than performance of yarn‐type rGO‐coated paper supercapacitors). Coating rGO or/and SWNTs on KTP gives good morphology to the composite film, in which porosity increases and mean pore diameter decreases. The yarn‐type rGO/SWNT paper supercapacitor shows good mechanical strength, high flexibility, excellent electrochemical performance, and long‐life operation. The yarn‐type supercapacitor has an excellent electrochemical performance with a specific capacitance of 366 F g^?1 at scan rate of 25 mV s^?1 and high stability without any degradation in electrical performance up to 10 000 charge–discharge cycles. The average capacitance of rGO/SWNT@KTP yarn‐type supercapacitors is seven times higher than that of sheet‐type supercapacitors at scan rate of 500 mV s^?1. The lighting of a red light‐emitting diode (LED) is demonstrated by the yarn‐type paper supercapacitor without connecting supercapacitors in series.     

A potato carboxypeptidase inhibitor gene provides pathogen resistance in transgenic rice

A defensive role against insect attack has been traditionally attributed to plant protease inhibitors. Here, evidence is described of the potential of a plant protease inhibitor, the potato carboxypeptidase inhibitor (PCI), to provide resistance to fungal pathogens when expressed in rice as a heterologous protein. It is shown that rice plants constitutively expressing the pci gene exhibit resistance against the economically important pathogens Magnaporthe oryzae and Fusarium verticillioides . A M. oryzae carboxypeptidase was purified by affinity chromatography and further characterized by mass spectrometry. This fungal carboxypeptidase was found to be a novel carboxypeptidase B which was fully inhibited by PCI. Overall, the results indicate that PCI exerts its antifungal activity through the inhibition of this particular fungal carboxypeptidase B. Although pci confers protection against fungal pathogens in transgenic rice, a significant cost in insect resistance is observed. Thus, the weight gain of larvae of the specialist insect Chilo suppressalis (striped stem borer) and the polyphagous insect Spodoptera littoralis (Egyptian cotton worm) fed on pci rice is significantly larger than that of insects fed on wild-type plants. Homology-based modelling revealed structural similarities between the predicted structure of the M. oryzae carboxypeptidase B and the crystal structure of insect carboxypeptidases, indicating that PCI may function not only as an inhibitor of fungal carboxypeptidases, but also as an inhibitor of insect carboxypeptidases. The potential impact of the pci gene in terms of protection against fungal and insect diseases is discussed.     

Rhizosphere fungal community structure succession of Xinjiang continuously cropped cotton

The large-scale long-term plantation of cotton in the Xinjiang region has been accompanied by a regular and wide outbreak of soil-borne fungal diseases such as verticillium wilt, which significantly damaged the local cotton industry. High-throughput sequencing data showed that the cotton field cultivation management measures pose a significant influence upon the original ecological soil fungal community structure. During long-term continuous cropping of cotton, a new soil fungal community structure emerges after several repeated adjustments over five years. The number of verticillium wilt pathogens in the soil increased rapidly with prolonged continuous cropping time, reaching a maximum at around the 10th y; moreover, the abundance of the verticillium wilt pathogen only serves as one of numerous essential factors for disease occurrence. The fungal community structure and the abundance of verticillium wilt pathogens in local cotton fields are gradually formed under joint effects of year-long continuous cropping and supporting cultivation management measures.     

Studies on the rhizosphere mycoflora of broad bean and cotton

Summary The fungal flora of the rhizosphere of three varieties of broad bean and cotton was studied by the dilution-plate technique. The numbers of fungi were higher in the rhizosphere than in the non-rhizosphere soil. Plant type and age, and soil type have a significant influence of the nature and numbers of fungal flora associated with plant roots.Cladosporium was relatively more abundant in the rhizosphere of broad bean varieties, whilePenicillium was found to constitute a high percentage of fungi found in the rhizosphere of cotton varieties. Plant variety has no influence on the nature of such fungal flora.     

Microbial cellulolytic activity of the brackish water in the Tvärminne area,Northern Baltic Sea

Microbial cellulolytic activity was determined by an indirect method (loss of tensile strength in cotton yarn). The activity values were high in late autumn, but low in spring and early summer. The factors responsible for the seasonal variation are discussed.     

Species richness and species composition of fungal communities associated with cellulose decomposition at different altitudes on the Tibetan Plateau

Aims The aims of this study were to compare the fungal communities developing on cotton strips at three different altitudes on the Tibetan Plateau and to assess the environmental variables influencing them.Methods Cotton strips that had been buried in soil for a year were sampled at three sites at different altitudes (4500, 4950 and 5200 m) located on a southeast-facing slope on the Nyainqentanglha Mountains near Damxung. The fungi on the cotton strips were isolated using a modified washing method. The decomposition abilities and colony growth properties of the major species cultured in pure-culture conditions were investigated and compared. Canonical correspondence analysis (CCA) was used to evaluate the relationships between fungal community composition and environmental variables (altitude, soil depth, soil water content [SWC], plant root mass and gravel content).Important findings A total of 24 species were isolated from the cotton strips, and 12 species occurred frequently and were regarded as major species. The number of fungal species was lower at the 4950-m altitude site than at the other two sites, indicating that not only altitude but also other factors affected the number of species present. All of the major species were able to decompose the cotton strips. In the CCA ordination, automatic forward selection revealed that altitude, SWC and plant root mass significantly affected fungal species composition. Our results suggest that species number and the composition of cellulolytic fungal communities are highly correlated with environmental variables as well as altitude in the alpine meadow on the Tibetan Plateau.     

The Inhibition of Fungal Growth in Resistant Cotton Plants Infected by Fusarium oxysporum f. sp. vasinfectum

The vascular colonization of cotton plants by Fusarium oxysporum f. sp. vasinfectum was determined by examining growth of the fungus from free-hand cross sections taken from 0 to six days after inoculation at various distances above the points of root inoculation. Fungal spread in both longitudinal and lateral directions in the susceptible cultivar Rowden was evident four days after inoculation, whereas fungal spread in the resistant cultivar Seabrook Sea Island was restricted. The quantity of viable fungus in infected tissues was determined from macerated tissues plated on Czapek- Dox agar. The colony counts declined within six days after inoculation in resistant Seabrook Sea Island, but not in susceptible Rowden, implying that an inhibition of fungal growth in vascular tissues occurred in resistant Seabrook Sea Island. This inhibition could contribute to the restriction of fungal spread and thus be a factor in the resistance of cotton plants to F. oxysporum f. sp. vasinfectum .     

First report of leaf spot disease caused by Corynespora torulosa MCC-1368 on cotton plant from India

In present study, the leaf spot disease of cotton plant emerged in the North Maharashtra region of India was reported. The fungal phytopathogen associated with inducing the leaf spot disease symptoms was isolated and characterised. The isolated fungus was identified as Corynespora torulosa (Deposition accession number, MCC-1368; Genbank accession no. MF462072) based on morphological and cultural characteristics and molecular analysis of ITS region. The pathogenicity of fungal phytopathogen was verified by Koch’s postulates. To our knowledge, this is the first report of incidence of leaf spot disease caused by Corynespora torulosa on cotton plant.     

基因沉默技术在抗真菌病害中的应用和展望

真菌病害严重威胁作物的产量和品质,给国家和人民造成巨大的经济损失。尤其是引起维管束病害的土传真菌,化学农药的作用效果很不理想。利用抗性基因进行遗传育种是目前生物防治的重要手段之一,但对于缺乏抗性资源的物种,面对强大的土壤真菌病害,研究者也时常束手无策。近年来,利用RNA干扰技术发展而来的宿主诱导的基因沉默(Host induced gene silencing,HIGS)策略,在抗病虫害领域逐渐崭露头角,但由于真菌侵染的复杂多样性及土壤传播的特性,HIGS在土壤真菌病害中的应用充满神秘和挑战。本研究室近期揭示了棉花黄萎病(一种严重的土壤真菌病害)的"罪魁祸首"——大丽轮枝菌的侵染结构和侵染过程;并首次证明了宿主植物内源小RNA能够跨界进入病原菌细胞中降解致病基因表达的抗病作用;在此基础上,本研究室利用HIGS在棉花上获得了对黄萎病抗性较高的品系,成功地开辟了抗土壤黄萎真菌病害的新天地,研究结果显示出基因沉默技术在这一领域强大的应用潜力和前景。     

Activation of a Bean Chitinase Promoter in Transgenic Tobacco Plants by Phytopathogenic Fungi

The temporal and spatial expression of a bean chitinase promoter has been investigated in response to fungal attack. Analysis of transgenic tobacco plants containing a chimeric gene composed of a 1.7-kilobase fragment carrying the chitinase 5B gene promoter fused to the coding region of the gus A gene indicated that the chitinase promoter is activated during attack by the fungal pathogens Botrytis cinerea, Rhizoctonia solani, and Sclerotium rolfsii. Although induction of [beta]-glucuronidase activity was observed in tissues that had not been exposed to these phytopathogens, the greatest induction occurred in and around the site of fungal infection. The increase in [beta]-glucuronidase activity closely paralleled the increase in endogenous tobacco chitinase activity produced in response to fungal infection. Thus, the chitinase 5B-gus A fusion gene may be used to analyze the cellular and molecular details of the activation of the host defense system during pathogen attack.     

Synthesis of partly debranched starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride) catalyzed by horseradish peroxidase and the effect on adhesion to polyester/cotton yarn

We performed a dual-modification of starch via debranching and graft copolymerization to improve its adhesion to fibers. We synthesized the partly debranched starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride) (PDS-g-PATAC) using horseradish peroxidase in the presence of hydrogen peroxide and acetylacetone. PDSs of different molecular structures were prepared by debranching waxy cornstarch for different periods of time. With increasing debranching time, the degree of hydrolysis of PDS increased from 0.85 % (10 min) to 1.13 % (30 min), while the degree of branching decreased from 8.37 % to 7.99 %. Fourier transform infrared analysis confirmed that ATAC units had been successfully grafted onto the starch (debranched or not debranched). The degree of substitution (DS) and grafting ratio (GR) of the PDS-g-PATACs were characterized by ¹H nuclear magnetic resonance. The DS and GR of grafted starches positively related with debranching time. Thermogravimetry-differential thermogravimetry analysis showed that grafted starch had lower thermal stability than ungrafted starch. The adhesion of PDS-g-PATAC to polyester/cotton yarns was evaluated. The PATAC chains grafted onto the starch enhanced the adhesion of starch to polyester/cotton yarn. The grafted starch produced from the copolymerization of PDS (after debranching for 10 min), exhibited the strongest adhesion to polyester/cotton yarn with a resulting tensile strength of 98.20 N.     

Transgenic expression of plant chitinases to enhance disease resistance

Crop plants have evolved an array of mechanisms to counter biotic and abiotic stresses. Many pathogenesis-related proteins are expressed by plants during the attack of pathogens. Advances in recombinant DNA technology and understanding of plant–microbe interactions at the molecular level have paved the way for isolation and characterization of genes encoding such proteins, including chitinases. Chitinases are included in families 18 and 19 of glycosyl hydrolases (according to www.cazy.org) and they are further categorized into seven major classes based on their aminoacid sequence homology, three-dimensional structures, and hydrolytic mechanisms of catalytic reactions. Although chitin is not a component of plant cell walls, plant chitinases are involved in development and non-specific stress responses. Also, chitinase genes sourced from plants have been successfully over-expressed in crop plants to combat fungal pathogens. Crops such as tomato, potato, maize, groundnut, mustard, finger millet, cotton, lychee, banana, grape, wheat and rice have been successfully engineered for fungal resistance either with chitinase alone or in combination with other PR proteins.     

Fungi associated with boll and lint rot of cotton in Southern Khorasan province of Iran

During surveys of cotton fields since 2009 in the Southern Khorasan province of Iran, symptomatic samples with lint and boll rot disease signs were collected and cultured on potato dextrose, malt extract agar and PARPH media. Several fungal isolates were obtained and identified. Among them, we found Penicillium expansum which to our knowledge is reported as a new pathogen of cotton worldwide; Fusarium semitectum and Nigrospora oryzae (associated to mite Siteroptes sp.) were also recorded as lint or boll rot pathogens for the first time from Iran. Disease symptoms and fungal characteristics of Exserohilum rostratum, which has been reported briefly as a new causal agent of boll and lint rot disease, are illustrated and presented. In addition, Aspergillus niger and Rhizopus spp. were also isolated frequently from lint parts of cotton prior to harvesting. There was a positive correlation between disease occurrence and spiny cotton bollworm damage. The pathogenicity test was characterised by inoculating the attached and detached bolls of cotton plants.