6 research outputs found
Exploring breast cancer diagnosis with fractal analysis and classification methods
No full textScreening and diagnostic mammography are the most effective
tools available for detection and diagnosis of breast cancer. In the last
decade many techniques based upon measures of the shape of the contours
of breast masses are been developed to investigate the nature of lesions
between malignant tumours and benign masses. This paper presents
methods for statistical analysis on a data set of 192 contours of breast
masses. Results of these analysis lead to levels of accurate prediction in
90% of the cases, overcoming 98% for the diagnosis of malignant lesions.
In this study we applied multivariate statistical techniques for examining
relationships among more variables at the same time. We used in addition
to the shape factors of contour masses also the age of the patients at the
time of mammography, using both ROC analysis and segmentation
analysis through Classification and Regression Tree
Transcript accumulation of polygalacturonase inhibiting protein (PGIP) following pathogen infections in soybean
No full textProteins inhibiting fungal endo-polygalacturonase (PGIP) are constitutively expressed and localized on cell walls of most plant species. Induction of pgip transcripts following pathogen infection would demonstrate a role of PGIP in active plant defence mechanisms. We investigated pgip expression in hypocotyls of soybean seedlings (cvs 'Sapporo' and 'Kure') infected with the fungal pathogens Diaporthe phaseolorum var. caulivora, Sclerotinia sclerotiorum and an avirulent (race 1) and virulent (race 20) races of Phytophthora sojae. Two pgip transcripts were transiently expressed in all types of interaction with similar timing and maximum accumulation at 16-24 h after infection. However, soybean seedlings of both cvs infected with the virulent race 20 of P. sojae showed higher levels of pgip expression than seedlings infected with the avirulent race 1. A delay of pgip accumulation was observed when plants were inoculated with zoospores in place of mycelium of P. sojae. The presence of endo-polygalacturonase (endo-PG) in infected tissue was monitored both by immunological detection and by determining PG activity. PG was detected only in soybean seedlings infected with S. sclerotiorum and not in those infected with D. phaseolorum var. caulivora or P. sojae. The apparent inability in vivo of the virulent and avirulent races of P. sojae to produce PG suggests that PG-PGIP interaction is not required for the resistance response of soybean against this pathogen
PURIFICATION AND MOLECULAR CHARACTERIZATION OF A SOYBEAN POLYGALACTURONASE-INHIBITING PROTEIN
No full textA polygalacturonase-inhibiting protein (PGIP) was detected in soybean (Glycine max (L.) Merr.) seedlings. The protein was purified from germinating seeds and appeared to consist of at least three components with very close molecular weights (between 37 and 40 kDa) but each showing a unique N-terminal sequence. Primers specific for N-terminal and C-terminal nucleotide sequences of field bean (Phaseolus vulgaris L.) PGIP were used in a polymerase chain reaction (PCR) on soybean DNA, and only one amplification band was obtained. The amplified product was cloned and one of the PCR clones was sequenced. The nucleotide sequence comprises 942 bp with a single open reading frame which encodes a polypeptide of 313 amino-acid residues with a predicted molecular weight of 33984 Daltons and an isoelectric point of 8.21. Analysis of genome organization showed a single gene copy of PGIP with few related sequences, and wounding of soybean hypocotyls showed a strong induction of expression of the PGIP gene. The PGIP showed different activities toward three purified fungal endo-polygalacturonases (endo-PGs) (two endo-PGs from Sclerotinia sclerotiorum and one endo-PG from Aspergillus niger). A possible involvement of soybean PGIP in plant defence against fungal pathogens is discussed
Structural and function features of wheat and rice polygalacturonase inhibiting proteins (PGIPs) and addition of novel PGIP recognition capabilities in wheat
No full textPolygalacturonase-inhibiting proteins (PGIPs) are plant defence glicoproteins associated with the cell wall of both
monocot and dicot species. They interact with fungal endopolygalacturonases (PGs) and modulate their activity
favouring the accumulation of oligogalacturonides active as elicitors of plant defence responses. A number of pgip
genes and of their encoded products have been characterized from dicot species, whereas only a few data are available
for PGIPs from monocots. In this work we report the structural and functional characterization of PGIPs and of their
encoding genes from wheat and rice and the effect of the over expression of a bean PGIP in wheat. Deduced amino acid
sequences of PGIP from both rice and wheat show the typical LRR organization and a conserved distribution of
cysteines. Nevertheless, the overall amino acid sequence similarity with PGIPs from dicots never exceeds 40%. To
determine their recognition specificities, wheat and rice pgip genes have been expressed in Nicotiana benthamiana
using the potato virus X (PVX) as vector. Only rice OsPGIP1, and to a lesser extent the wheat TaPGIP1, are active
against the fungal pathogen PGs tested, whilst OsPGIP2 and OsPGIP3 show none inhibition. We have also found that
the lack of an entire LRR repeat in rice OsPGIP1 does not affect the ability of recognizing fungal PGs.
To verify the involvement of PGIP in protecting wheat from fungal pathogens producing PG, such as Fusarium
graminearum, we have performed quantitative RT-PCR (qRT-PCR) analysis in infected wheat tissue and produced
transgenic wheat with a bean PGIP possessing a wide spectrum of recognition towards fungal PGs. qRT-PCR showed
induction of Tapgip1 following infection with F. graminearum and preliminary infection experiments with the same
pathogen indicate that the transgene-encoded protein is active and endows the transgenic wheats with new PG
recognition capabilities
Transgenic expression of polygalacturonase-inhibiting proteins in Arabidopsis and wheat increases resistance to the flower pathogen Fusarium graminearum
No full textFusarium head blight (FHB), caused by Fusarium graminearum, is one of the most important diseases of wheat worldwide, resulting in yield losses and mycotoxin contamination. The molecular mechanisms regulating Fusarium penetration and infection are poorly understood. Beside mycotoxin production, cell wall degradation may play a role in the development of FHB. Many fungal pathogens secrete polygalacturonases (PGs) during the early stages of infection, and plants have evolved polygalacturonase-inhibiting proteins (PGIPs) to restrict pectin degradation during fungal infection. To investigate the role of plant PGIPs in restricting the development of FHB symptoms, we first used Arabidopsis thaliana, whose genome encodes two PGIPs (AtPGIP1 and AtPGIP2). Arabidopsis transgenic plants expressing either of these PGIPs under control of the CaMV 35S promoter accumulate inhibitory activity against F. graminearum PG in their inflorescences, and show increased resistance to FHB. Second, transgenic wheat plants expressing the bean PvPGIP2 in their flowers also had a significant reduction of symptoms when infected with F. graminearum. Our data suggest that PGs likely play a role in F. graminearum infection of floral tissues, and that PGIPs incorporated into wheat may be important for increased resistance to FHB
The Perceptions of members of the Karen and Hmong Hill tribes of the impacts upon their communities resulting from the development of tourism in Northern Thailand.
No full textThis research investigates the perceptions of hill tribe people in Northern Thailand of the sociocultural impacts and changes in their communities resulting from the interaction between themselves, their communities and the incoming mainly Thai, origin, external tourism actors
(ETAs), such as tourism authorities, tourism businessmen / investors and tour operators. In Thailand, most studies on the impacts of tourism have been limited to economic analyses, and the socio-cultural impacts of tourism on hill tribe people has been under-researched. Of the previous studies of the socio-cultural impacts of tourism, the majority have examined the impacts from host and guest interactions, emphasising the negative social impacts resulting from the influx of tourists in general. Specific research on the interaction of local hill tribe people with incoming ETAs has not been reported. To fill this gap, this research aims to compare the perceptions of two hill tribe peoples (the Karen and Hmong), both those working for ETAs and those who do not, in terms of their employment experiences and perceived socio-cultural impacts resulting from the arrival of ETAs. In order to achieve the research aim, a combination of qualitative and quantitative methods was used. A sequential approach was adopted incorporating a mixed methods design in order to better answer the research challenge of exploring the participants' views and perceptions. Building on a thorough literature review the first phase of primary data collection adopted a
qualitative approach. Focus groups were used to explore the local hill tribe perceptions towards the interaction between ETAs and themselves, and their perceptions towards socio-cultural impacts upon themselves and changes in their community. Then semi-structure interviews were used to gain more in-depth details from selected participants. Themes from this qualitative phase were then used in the second stage of primary data collection to develop an essentially
quantitative questionnaire, to measure, by means of a large scale survey, the perceptions of the selected population.
The fmdings suggest that exposure to the social and cultural characteristics of ETAs, have significantly influenced some of the values, beliefs and lives of tribal people. However, despite the impacts resulting from the arrival of ETAs, these hill tribe people tend to be in favour and perceive these impacts and changes as positive changes. Moreover, the fmdings also suggest that differences in ethnic background, working environment
and gender can be factors that influence perceptions of these hill tribe people. However, each factor, ethnicity, working environment, gender, exerts differing degrees of influence upon the perceptions of these hill tribe people toward different issues regarding impacts from ETAs. In
addition, individual's perceptions toward impacts from ETAs differ despite their having the same ethnic background. However, the evidence gathered suggests that ethnic background does still control, to a degree, these differences with the result that while people's perceptions do differ in many ways nevertheless those from the same ethnic background tend to show greater similarities in their perceptions and actions when compared to those of different ethnicities. To this end, this study has pointed out several recommendations for future research together
with the implications of the findings from this research on tourism management and policy makers
