Strategies for improved disease resistance in micro-propagated bananas

Bananas (Musa sp) are one of the most important food crops in the world and provide a staple food and source of income in many households especially in Africa. Diseases are a major constraint to production with bunchy top, caused by Banana bunchy top virus (BBTV) generally considered the most important virus disease of bananas worldwide. Of the fungal diseases, Fusarium wilt, caused by the Fusarium oxysporum f.sp cubense (Foc), and black Sigatoka, caused by Mycosphaerella fijiensis, are arguably two of the most important and cause significant yield losses. The low fertility of commercially important banana cultivars has hampered efforts to generate disease resistance using conventional breeding. Possible alternative strategies to generate or increase disease resistance are through genetic engineering or by manipulation of the innate plant defence mechanisms, namely systemic acquired resistance (SAR). The first research component of this thesis describes attempts to generate BBTV-resistant banana plants using a genetic modification approach. The second research component of the thesis focused on the identification of a potential marker gene associated with SAR in banana plants and a comparison of the expression levels of the marker gene in response to biotic and abiotic stresses, and chemical inducers. Previous research at QUT CTCB showed that replication of BBTV DNA components in banana embryogenic cell suspensions (ECS) was abolished following co-bombardment with 1.1mers of mutated BBTV DNA-R. BBTV DNA-R encodes the master replication protein (Rep) and is the only viral protein essential for BBTV replication. In this study, ECS of banana were stably transformed with the same constructs, each containing a different mutation in BBTV DNA-R, namely H41G, Y79F and K187M, to examine the effect on virus replication in stably transformed plants. Cells were also transformed with a construct containing a native BBTV Rep. A total of 16, 16, 11 and five lines of stably transformed banana plants containing the Y79F, H41G, K187M and native Rep constructs, respectively, were generated. Of these, up to nine replicates from Y79F lines, four H41G lines, seven K187M lines and three native Rep lines were inoculated with BBTV by exposure to viruliferous aphids in two separate experiments. At least one replicate from each of the nine Y79F lines developed typical bunchy top symptoms and all tested positive for BBTV using PCR. Of the four H41G lines tested, at least one replicate from three of the lines showed symptoms of bunchy top and tested positive using PCR. However, none of the five replicates of one H41G line (H41G-3) developed symptoms of bunchy top and none of the plants tested positive for BBTV using PCR. Of the seven K187M lines, at least one replicate of all lines except one (K187M-1) developed symptoms of bunchy top and tested positive for BBTV. Importantly, none of the four replicates of line K187M-1 showed symptoms or tested positive for BBTV. At least one replicate from each of the three native Rep lines developed symptoms and tested positive for BBTV. The H41G-3 and K187M-1 lines possibly represent the first transgenic banana plants generated using a mutated Rep strategy. The second research component of this thesis focused on the identification of SAR-associated genes in banana and their expression levels in response to biotic and abiotic stresses and chemical inducers. The impetus for this research was the observation that tissue-cultured (TC) banana plants were more susceptible to Fusarium wilt disease (and possibly bunchy top disease) than plants grown from field-derived suckers, possibly due to decreased levels of SAR gene expression in the former. In this study, the pathogenesis-related protein 1 (PR-1) gene was identified as a potential marker for SAR gene expression in banana. A quantitative real-time PCR assay was developed and optimised in order to determine the expression of PR-1, with polyubiquitin (Ubi-1) found to be the most suitable reference gene to enable relative quantification. The levels of PR-1 expression were subsequently compared in Lady Finger and Cavendish (cv. Williams) banana plants grown under three different environmental conditions, namely in the field, the glass house and in tissue-culture. PR-1 was shown to be expressed in both cultivars growing under different conditions. While PR-1 expression was highest in the field grown bananas and lowest in the TC bananas in Lady Finger cultivar, this was not the case in the Cavendish cultivar with glass house plants exhibiting the lowest PR-1 expression compared with tissue culture and field grown plants. The important outcomes of this work were the establishment of a qPCR-based assay to monitor PR-1 expression levels in banana and a preliminary assessment of the baseline PR-1 expression levels in two banana cultivars under three different growing conditions. After establishing the baseline PR-1 expression levels in Cavendish bananas, a study was done to determine whether PR-1 levels could be increased in these plants by exposure to known banana pathogens and non-pathogens, and a known chemical inducer of SAR. Cavendish banana plants were exposed to pathogenic Foc subtropical race 4 (FocSR4) and non-pathogenic Foc race 1 (Foc1), as well as two putative inducers of resistance, Fusarium lycopersici (Fol) and the chemical, acibenzolar-S-methyl (BION®). Tissue culture bananas were acclimatised under either glass house (TCS) or field (TCH) conditions and treatments were carried out in a randomised complete block design. PR-1 expression was determined using qPCR for both TCS and TCH samples for the period 12-72h post-exposure. Treatment of TCH plants using Foc1 and FocSR4 resulted in 120 and 80 times higher PR-1 expression than baseline levels, respectively. For TCS plants treated with Foc1, PR-1 expression was 30 times higher than baseline levels at 12h post-exposure, while TCS plants treated with FocSR4 showed the highest PR-1 expression (20 times higher than baseline levels) at 72h post-exposure. Interestingly, when TCS plants were treated with Fol there was a marked increase of PR-1 expression at 12 h and 48 h following treatment which was 4 and 8 times higher than the levels observed when TCS plants were treated with Foc1 and FocSR4, respectively. In contrast, when TCH plants were treated with Fol only a slight increase in PR-1 expression was observed at 12 h, which eventually returned to baseline levels. Exposure of both TCS and TCH plants to BION® resulted in no effect on PR-1 expression levels at any time-point. The major outcome of the SAR study was that the glass house acclimatised tissue culture bananas exhibited lower PR-1 gene expression compared to field acclimatised tissue culture plants and the identification of Fol as a good candidate for SAR induction in banana plants exhibiting low PR-1 levels. A number of outcomes that foster understanding of both pathogen-derived and plant innate resistance strategies in order to potentially improve banana resistance to diseases were explored in this study and include identification of potential inducers of systemic acquired resistance and a promising mutated Rep approach for BBTV resistance. The work presented in this thesis is the first report on the generation of potential BBTV resistant bananas using the mutated Rep approach. In addition, this is the first report on the status of SAR in banana grown under different conditions of exposure to the biotic and abiotic environment. Further, a robust qPCR assay for the study of gene expression using banana leaf samples was developed and a potential inducer of SAR in tissue culture bananas identified which could be harnessed to increase resistance in tissue culture bananas.

Unmodified silver nanoparticles for rapid analysis of the organophosphorus pesticide, dipterex, often found in different waters

A novel, uncomplicated and rapid method of analysis for organophosphorus (OP) pesticides was researched and developed using the important, common OP, dipterex, as a typical example. The basis of the method involved the citrate-capped silver nanoparticles (citrate-capped AgNPs) and Acetylthiocholine (ATCh). The latter compound can be catalyzed by Acetylcholinesterase (AChE) to form thiocholine (TCh), which induces the aggregation of AgNPs. Correspondingly, the color of AgNPs in solution changes from bright yellow to pink, and the UV–vis characteristic absorption peak of AgNPs at about 400 nm decreases; simultaneously, a new absorption band appears at about 520 nm. Irreversible inhibition of AChE activity caused by dipterex, prevents the aggregation of AgNPs. Thus, a UV–vis spectrophotometric method was developed for the analysis of dipterex. The absorbance ratio A396 nm/A520 nm was found to be linearly related to the concentration of dipterex in the range of 0.25–37.5 ng mL−1 with a detection limit of 0.18 ng mL−1. This method was used successfully to analyse dipterex in spiked, different water samples.

Growing Up Vietnamese in Finland - Looking Back 12 Years Later : The Well-Being and Sociocultural Adaptation of Vietnamese as Children or Adolescents and as Young Adults

Varttuminen vietnamilaisena Suomessa: 12 vuoden seurantajakso – Vietnamilaisten hyvinvointi ja sosiokulttuurinen sopeutuminen lapsena/nuorena sekä nuorena aikuisena Tämä tutkimus oli määrällinen pitkittäistutkimus lapsena tai nuorena vuosina 1979-1991 Suomeen saapuneiden vietnamilaisten akkulturaatiosta (kulttuurin muutoksista), psyykkisestä hyvinvoinnista ja sosiokulttuurisesta sopeutumisesta. Tutkimukseen osallistui ensimmäisessä vaiheessa (vuonna 1992) 97 satunnaisesti valittua vietnamilaista peruskoululaista ympäri maata, joita verrattin suomalaisiin luokkatovereihin. Seurantavaiheeseen (vuonna 2004) osallistui 59 ensimmäisessä vaiheessa mukana ollutta vietnamilaista, nyt iältään 20 – 31 -vuotiaita. Tutkimuksen tavoitteena oli selvittää mitkä tekijät ennustivat akkulturaation lopputuloksia, samalla huomioiden iän ja ympäristön (kontekstin) vaikutukset psyykkiseen hyvinvointiin ja sosiokulttuuriseen sopeutumiseen. Yksittäiset akkulturaatiodimensiot (kieli, arvot ja identiteetti) osoittautuivat tärkeämmiksi psyykkiselle hyvinvoinnille ja sosiokulttuuriselle sopeutumiselle kuin etniset, kansalliset tai kaksikulttuuriset profiilit, joissa yhdistyivät ao. kieli, arvot ja identiteetti. Identiteettimuutosta tapahtui (etniseen) vietnamilaiseen suuntaan ajan kuluessa, kun taas arvomuutosta tapahtui (kansalliseen) suomalaiseen suuntaan. Sekä suomen että vietnamin kielen taito lisääntyivät ajan myötä, millä oli myönteisiä vaikutuksia sekä psyykkiseen hyvinvointiin että sosiokulttuuriseen sopeutumiseen. Lähtötilanteen psyykkinen hyvinvointi ennusti hyvinvointia (masennuksen puutetta ja itsetuntoa) aikuisena, mutta sosiokulttuurinen sopeutuminen (koulumenestys) lapsena tai nuorena ei ennustanut kouluttautumista aikuisena. Parempi suomen kielen taito ja vähemmän identifioitumista suomalaiseksi aikuisena sekä masentuneisuuden puute ja vähemmän koettua syrjintää lapsena tai nuorena erottelivat psyykkisesti paremmin voivat aikuiset (ei-masentuneet) heistä, jotka olivat masentuneita. Parempaa kouluttautumista aikuisena ennustivat toisaalta vähemmän koettua syrjintää lapsena tai nuorena ja toisaalta aikuisena parempi suomen kielen taito, suurempi kansallisten (suomalaisten) itsenäisyysarvojen kannattaminen, mutta kuitenkin vähemmän identifioitumista suomalaisiin. Koetun syrjinnän merkitys psyykkiselle hyvinvoinnille, erityisesti lapsena tai nuorena, sekä sen pitkäaikaisvaikutukset psyykkiselle hyvinvoinnille ja sosiokulttuuriselle sopeutumiselle aikuisena osoittavat tarpeen puuttua varhain psyykkisiin ongelmiin sekä parantaa etnisten ryhmien välisiä suhteita. Avainsanat: akkulturaatio, psyykkinen hyvinvointi, sosiokultuurinen sopeutuminen, kieli, arvot, identiteetti, vietnamilainen, Suomi, lapset, nuoret, nuoret aikuiset

Developing acetylcholinesterase-based inhibition assay by modulated synthesis of silver nanoparticles: applications for sensing of organophosphorus pesticides

A novel and highly sensitive sensing strategy for the detection of organophosphorus compounds (OPs) based on the catalytic reaction of acetylcholinesterase (AChE) and acetylcholine (ATCh) during the modulated synthesis of silver nanoparticles (AgNPs) has been developed. The enzymatic hydrolysis of ATCh by AChE yields thiocholine (TCh), which induces the aggregation of AgNPs during synthesis, and the absorption peak at 382 nm corresponding to AgNPs decreases. The enzymatic reaction can be regulated by OPs, which can covalently bind to the active site of AChE and decrease the TCh formation, thereby decreasing the aggregation and significantly enhancing the absorption peak at 382 nm. The proposed system achieved good linearity and limits of detection of 0.078 nM and 2.402 nM for trichlorfon and malathion, respectively, by UV-visible spectroscopy. Further, the sensitivity of the proposed system was demonstrated through the determination of OPs in different spiked real samples. The described work shows the potential application for further development of a colorimetric sensor for other OP pesticide detection during the synthesis of AgNPs using enzyme-based assays.

猪STCH 基因的Bi2PASA 遗传标记及多态性研究

微粒体应激70 蛋白三磷酸腺苷酶( S TCH) 基因属于应激70 蛋白基因伴侣家族, 在机体免疫反应 和疾病抵抗力等方面起重要作用。根据人和小鼠S TCH 基因的保守序列设计引物, PCR 扩增到猪S TCH 基因第 5 外显子445 bp 片段。序列测定显示, 猪S TCH 基因与人和小鼠S TCH 基因分别具有87113 %和80145 %的同源 性。通过测定和比较中国梅山猪、欧洲约克夏猪及PIC 商品猪的S TCH 基因序列, 发现在猪S TCH 基因编码区 第5 外显子1 050 位点上存在一个单碱基突变位点。利用双向特定等位基因PCR 扩增法(Bi2PASA) 建立了检测 猪S TCH 基因变异的遗传标记, 并用该标记分析了S TCH 基因在中国家猪(梅山猪、荣昌猪和金华猪) 、欧洲家 猪(约克夏猪、大白猪) 、商品猪(PIC 合成系) 以及欧洲野猪的基因频率和多态性。本研究建立的Bi2PASA 遗 传标记和基因变异信息, 将为进一步分析猪S TCH 基因变异与经济性状的相关分析提供基础资料。

2型糖尿病患者认知功能特点及相关影响因素研究

Objective: Type 2 diabetes patients’ performances of action memory , semantic memory and working memory and the related factors were explored. Methods: 60 Type 2 diabetes patients were compared with 60 age and gender and level of education matched non-diabetes controls. Mood were tested by SAS and SDS, MMSE was used to test the basic cognitive function, Trail Making Test A and B, Verbal fluency test, Go-No/Go test, and Stroop color-word test were used to investigate the executive function of Type 2 diabetes patients and normal controls (NC). Patients’ GLU, TG, TCH, HbA1c, insulin and Cp were tested and correlated with their action memory and working memory. Results: There was no difference between NC group and Type 2 diabetes patients in MMSE scores. There is depression and anxiety mood in Type 2 diabetes patients. Type 2 diabetes patients get lower score in action memory test. Comparing to NC group, Type 2 diabetes patients performed significantly worse in Trail Making Test A and B and verbal fluency test. In Stroop Test, NC group showed significant Stroop Effect and Repeated Distraction Promotion Effect and Negative Priming Effect. However, In Type 2 diabetes group, only the Stroop Effect appeared, but no Repeated Distraction Promotion Effect and Negative Priming Effect. There is no difference between Type 2 diabetes and NC in Stroop Effect. In Go-No/Go test, both of two groups showed significant Stroop Effect, however, there was no difference between them. And also there is no difference on error rate of all levels between them. The course of disease, GL, HbA1c, TG, TCH, INS and Cp affected action memory and working memory. Conclusion: Type 2 diabetes patients’ action memory, semantic memory and working memory were partially impaired. Controlling the levels of GLU, TG and TCH can delay these kinds of impairment.

Modularité massive ou construction sociale? : une analyse de l'approche psychoévolutionniste de Cosmides et Tooby.

Ce mémoire se veut un examen épistémologique de la thèse psychoévolutionniste de Leda Cosmides et John Tooby, principalement en ce qui concerne la modularité massive. Nous avons tâché de voir si la modularité massive permet de rendre compte des processus mentaux complexes en nous penchant plus particulièrement sur le cas des émotions. Nous explorons d'abord la thèse de Cosmides et Tooby en la distinguant d'avec d'autres conceptions comme l'écologie béhaviorale et en expliquant le rôle particulier que jouent les émotions au sein de la théorie. Nous analysons ensuite la thèse de la modularité massive et les différents arguments théoriques ou empiriques qui l'appuient, et évaluons finalement des critiques de la modularité émises par certains philosophes, dont David Buller.

Feu, suivi de Sophie Calle : soi en négatif

Feu est un recueil photo-textuel autofictionnel dans lequel j’ai revisité des souvenirs amoureux suite à un incendie qui a tout rasé. À travers de brefs épisodes, j’ai tâché de transmettre les différentes émotions éprouvées pendant le deuil et de mettre en avant mon obsession pour le feu et mon ancien compagnon. Le ressassement égocentrique de souvenirs amène à un profond mal-être, puis se résorbe un peu lorsque vient une ouverture aux autres, mais demeure inachevé. Les photographies servent à illustrer le texte, à donner une autre dimension à l’autobiographie. Elles participent aussi à l’exposition de la solitude. En plus de certains intertitres qui font un clin d’œil à l’œuvre de Sophie Calle, je me suis inspirée de certains de ses traits caractéristiques. Sophie Calle: Soi en négatif est un essai portant sur la performance de soi. Il y est question de pacte autobiographique, d’intertextualité, d’altérité, de deuil et d’absence. Je tente d’esquisser comment elle s’y prend pour s’exposer. Non seulement elle exploite les aspects négatifs de sa vie et de celle des autres, mais elle se révèle par des intermédiaires, que ce soit d’autres personnes ou des documents. Ses mots et ses photos développent en quelque sorte la vie contenue dans ses archives personnelles. Lorsqu’elle s’expose, l’art dépasse la littérature, le cinéma, l’entrevue et la photographie pour devenir une performance de soi, en négatif.

Mini-trawls for Estuarine Fishing Kasargod District

Mi ni -trawls are operated by the artisanal fishermen from small wooden non-motorised canoes. Shrimp, fish and crab trawls wi th head rope length rang ing from 3.5-8 m, made of Po lyethy lene mon ofila ment (PE) twisted and Polyamide mullifilament (PA) rigged to 6-7 kll fla t rectangular wooden otter boards are common in the lower reaches of Kariango de and Chandrag iri rive rs. Since the trawling speed is less, ca tch is do minated by crus taceans. Less scope ratio also may be affecting the catching efficiency of the gear. This pape r deals with the design, operation and economics of mini traw ling carried out by a group of fisherme n in the above rivers of Kasargod district Kerala state.

Un panorama de la productividad del sector azucarero colombiano

El presente trabajo se basa en la investigación y análisis del sector azucarero, para presentar un panorama de la productividad del sector en Colombia. Para ello se utilizan tres países de referencia, Australia, Argentina y Guatemala, con los cuales se hace una comparación detallada a lo largo del trabajo. Éste trabajo consta de cinco partes. En la primera parte se realizará una introducción del sector azucarero en Colombia en comparación con otros países con diferentes niveles de producción de azúcar, y dos posibles indicadores para la medición de la productividad del sector en Colombia. En la segunda parte se planteará y describirá el problema de investigación junto con la pregunta a desarrollar a lo largo del trabajo. En la tercera parte se construirá un estado del arte, para así tomar como referencia otros estudios realizados sobre el tema. En la cuarta parte del trabajo se plantearán las posibles soluciones al problema de investigación. Y finalmente, en la quinta parte del trabajo se darán recomendaciones y se sacarán las conclusiones de todo el estudio. Teniendo como objetivo el análisis de la productividad del sector, se tomaran como base dos indicadores de productividad. El primero de ellos será el indicador de productividad laboral, el cual definirá el aumento o disminución de los rendimientos ocasionados por la variación de cualquiera de los factores que intervienen en la producción (trabajo, capital o tecnología) . Para medir este indicador se utiliza también el índice de Aporte Laboral (valor agregado /personal total), el cual muestra la gestión de los trabajadores mostrando la productividad media del trabajo. El segundo indicador que se analizará está medido por factores tales como: toneladas de azúcar, toneladas de caña y hectáreas por cosecha. Este indicador se podrá medir por medio del TAH-Cosecha (Tonelada de azúcar/hectárea) y el TCH-Cosecha (Tonelada de caña/hectárea) . Por medio de la construcción y análisis de estos indicadores se desea ver el impacto y relación de la productividad del sector azucarero en Colombia. A partir de este estudio se pretende brindar sugerencias para mejorar la productividad del sector azucarero colombiano, siendo este comparado con las prácticas y productividades de Argentina, Australia y Guatemala.