(T.S.C., B.U., M.P.)Various biochemical, chemical, and microspectroscopic methods have been developed throughout the years for the screening and identification of mutants with altered cell wall structure. However, these procedures fail to provide the insight into structural aspects of the cell wall polymers. In this paper, we present various methods for rapidly screening Arabidopsis cell wall mutants. The enzymatic fingerprinting procedures using high-performance anion-exchange-pulsed-amperometric detection liquid chromatography, fluorophore-assisted carbohydrate electrophoresis, and matrix-assisted laser-desorption ionization time of flight (MALDI-TOF) mass spectrometry (MS) were exemplified by the structural analysis of the hemicellulose xyloglucan. All three techniques are able to identify structural alterations of wall xyloglucans in mur1, mur2, and mur3, which in comparison with the wild type have side chain defects in their xyloglucan structure. The quickest analysis was provided by MALDI-TOF MS. Although MALDI-TOF MS per se is not quantitative, it is possible to reproducibly obtain relative abundance information of the various oligosaccharides present in the extract. The lack of absolute quantitation by MALDI-TOF MS was compensated for with a xyloglucan-specific endoglucanase and simple colorimetric assay. In view of the potential for mass screening using MALDI-TOF MS, a PERL-based program was developed to process the spectra obtained from MALDI-TOF MS automatically. Outliers can be identified very rapidly according to a set of defined parameters based on data collected from the wild-type plants. The methods presented here can easily be adopted for the analysis of other wall polysaccharides. MALDI-TOF MS offers a powerful tool to screen and identify cell wall mutants rapidly and efficiently and, more importantly, is able to give initial insights into the structural composition and/or modification that occurs in these mutants.

b-Galactosidase (EC 3.2.1.23) is a hydrolase which plays an important role in cell wall modification and fruit softening during ripening. In this study, three fulllength b-galactosidase cDNA clones were successfully obtained from papaya mesocarp using different approaches. pPGBII which is 2,771 bp in size, was isolated from a papaya ripe mesocarp cDNA library using a heterologous probe. The other two cDNA clones, pBG(a) and pBG(b), which are 3,168 and 2,580 bp in size, respectively, were amplified from ripe papaya fruit using the reverse transcriptase polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE) approaches. The pPBGII, pBG(a) and pBG(b) cDNAs, respectively, were expected to yield a putative mature polypeptide of 79, 91 and 56 kDa with isoelectric points (pI) of 8.12, 8.75 and 8.26. The genomic DNA gel blot analysis indicated that all of the b-galactosidase genes exist as multiple copies in the papaya genome hence they belong to a multigene family. All three cDNA clones were expressed in fruits during ripening with varying patterns. In mesocarp, pPBGII mRNA was only expressed during ripening and peaked at the half-ripe stage when the fruits undergo dramatic softening. Meanwhile, pBG(a) mRNA expression increased from the immature green stage to the half-ripe stage where it reached maximum level before declining. pBG(b) mRNA level accumulated abundantly at the mature green stage and decreased thereafter. Therefore, we suggest that pPBGII and pBG(a) cDNA clones characterized in this work may be involved in fruit softening during papaya ripening while the fruit-specific pBG(b) may be related to early ripening stage.

This review aims to evaluate the effectiveness of nutritional intervention in the treatment of pressure ulcers. Four databases were searched systematically using the keywords formulated and papers were selected according to inclusion and exclusion criteria. The literature search period included articles published from 1 January 2000 to 30 December 2011 (inclusive). Six papers on randomized controlled trials were retrieved. All six trials showed positive outcomes in pressure ulcer healing with nutritional interventions. Secondary outcomes such as lower number of dressings required, less time spent on dressing changes and lower occurrence of infections were reported. The main results emerged from this study generally supported the use of nutritional interventions in the treatment of pressure ulcers. Various methodological issues associated with these trials were highlighted. The implications for clinical practice need to bear in mind both the methodological problems raised and limitations of this review.

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