It is highly reliable for accurately determining the size distribution of cell-derived EMVs as it is based on Brownian motion, does not consider the refractive index of the nanoparticle, and is free from sample shrinkage artifacts commonly encountered during fixation for microscopy [47]. Vesicles obtained from 143B CM were devoid of contaminating vesicles from FBS [48]. Detection of MVBs

by TEM in 143B EMV samples suggests that the mode of biogenesis and release of EMVs is most likely through endocytic invagination followed by the formation of early endosomes that mature to www.selleckchem.com/products/gkt137831.html form MVBs. Size range of 143B EMVs as determined by NTA (50-200 nm), evidence of MVBs by TEM, and the presence of CD-9, an exosome-specific biomarker as listed in ExoCarta selleck chemicals database (Bundoora, Victoria, Australia), suggest that 143B EMVs contain exosomes. To our best knowledge, this is the first study to report the presence of a pro-osteoclastogenic cargo in EMVs isolated from 143B cells. Detection of MMPs (MMP-1 and MMP-13) in 143B EMVs is an important and novel finding because MMP-1– and MMP-13 (MMP)–expressing

EMVs could be used as disease biomarkers for evaluating osteosarcoma prognosis. Detection of RANKL in osteosarcoma EMVs is novel and significant as it plays an important role in the activation of MMPs and for stimulating osteoclastogenesis. Targeting MMP-1 expression and activity through RANKL inhibition is promising as recent studies by Casimiro et al. demonstrates a role of RANKL in the activation of MMP-1 expression and activity in breast cancer metastasis [49]. Whether selective inhibition of EMV-derived

RANKL and/or MMP-1 and MMP-13 inhibits osteosarcoma pathobiology remains to be investigated. Targeting RANK/RANKL/osteoprotegrin (OPG) signaling in osteosarcoma is currently under intense investigation, and studies with OPG and RANK-Fc demonstrate inhibition of osteolytic lesions in mouse models and improved survival rates [50] and [51]. Detection eltoprazine of TGF-β in 143B EMVs is an important finding especially in the context of regulating the bone TMN. In the BME, TGF-β is generated mainly from the mineralized bone matrix by osteoclastic resorption and further stimulates the production of osteolytic and proneoplastic factors [52] and [53]. It can stimulate migration of osteoblast progenitors and osteosarcoma cells either directly [54] or indirectly through osteoclast-mediated chemokine (C-X-C motif) ligand 16 (CXCL16) chemokine secretion [55]. It plays an important role in the osteoclastogenic differentiation of uncommitted monocytes by stimulating RANKL and/or tumor necrosis factor α (TNF-α)-induced nuclear factor of activated T-cells cytoplasmic, calcineurin dependent 1 (NFATc1) expression [38].

77), whereas males showed an isometric increase in weight with increasing CW (b = 3.02) ( Figure 5). The CW: WW ratio for all specimens was determined by the function CW = 0.0005 WW2.90 (R2 = 0.96, p < 0.05). The condition factor K of all R. harrisii taken together varied from 0.02 to 0.08 (mean 0.05 ± 0.01; n = 601). In females (n = 276) it ranged from 0.03 to 0.08 (mean 0.06 ± 0.08), whereas in males (n = 325) it was significantly lower (p < 0.05),

from 0.02 to 0.07 (mean 0.04 ± 0.06). The water content in the mud crabs varied from Volasertib purchase 57.9 to 91.5% of the total body weight (mean 73.6 ± 7.5%; n = 248), but this differed between juveniles and adults and between the sexes (juveniles: 65.1–87.5%, mean 74.1 ± 5.5%, n = 87; females: 57.9–91.3%, mean 74.9 ± 8.7%, n = 79; males: 58.6–91.5%, mean 71.8 ± 7.9%, n = 82). The water content was not significantly related (p > 0.05) to carapace width (CW), although there were statistically significant differences (p < 0.05) in water content between both sexes and between males and juveniles. Invasive species, for many reasons such as their broad environmental tolerances, can reduce native biological diversity and even become dominant organisms in non-native regions by replacing or coexisting with indigenous species (Ba et al. 2010). Although Rhithropanopeus harrisii has been present in the Gulf of Gdańsk for at least a decade, its negative influence on native

species has been not reported Prostatic acid phosphatase ( Hegele-Drywa & Normant 2014). Between 2006 and 2010, over 200 specimens of R. harrisii were collected each year, except for 2006 and 2009. In 2006, sampling started later than usual, and in 2009, LEE011 mw in order to obtain information on seasonal variations in crab abundance, the material was collected from only two depth profiles (see Hegele-Drywa & Normant 2014). Sexually mature specimens dominated the samples, and the sex ratio

was skewed slightly towards more males: this has been observed in other populations inhabiting Polish waters (i.e. the Dead Vistula River, the Vistula Lagoon and the Odra Estuary) (Turoboyski 1973, Rychter 1999, Normant et al. 2004, Czerniejewski & Rybczyk 2008, Czerniejewski 2009), Chesapeake Bay (Ryan 1956) and the Panama Canal (Roche & Torchin 2007). The dominance of males over females occurs frequently in crab populations, including other species from the Xanthidae family (De Goes & Fransozo 2000, Warburg et al. 2012). According to Morgan et al. (1988) this is normal in natural environments, but for high spawning rates it is more advantageous when there is a higher proportion of females. Laboratory studies showed that R. harrisii spawning was greater when males were less abundant than females, perhaps because a few males can mate with many females ( de Rivera et al. 2003). Additionally, females would be less vulnerable to attack by more aggressive males while moulting (Morgan et al. 1988). In 2009–2010 juveniles (< 4.

, 2009). With fish hepatocyte cultures as model system Scown et al. (2010) have noted their suitability for studies investigating the cellular uptake of engineered nanoparticles. Another model system for judging nanomaterials toxicity is zebrafish embryos; the model also being useful for comparative biology because of the similarities between the zebrafish and human genomes, early life development and disease processes. In a HCS assay study

on ZnO toxicity in rodent lung and zebra fish embryo’s, data indicated reduced toxicity in the latter system upon doping of Fe in ZnO ( Xia et al., 2011). Release of nanomaterials to the environment during recycling and disposal is of particular concern for nanoparticles incorporated into limited use and/or disposable products. Once released these nanomaterials would readily undergo transformations via biotic and abiotic processes. Understanding environmental transformations and fate of engineered nanomaterials will enable design and development of environmentally benign nanomaterials,

as well as their use as environmental tracers, in environmental sensing and in contaminant remediation. This was demonstrated in a biomimetic hydroquinone-based Fenton reaction which provides a new method to characterize transformations of nanoscale materials expected to occur under oxidative environmental conditions ( Metz et al., 2009). Current computational techniques are being used to study interactions of nanoparticles with biological Adriamycin cost systems and these have been reviewed by Makarucha et al. (2011). Such studies could also be used to complement Protirelin the experimental data on toxicity. Taking into consideration the routes of

exposure to nanoparticles, to better understand dermal absorption of nanomaterials more research on regular skin, dry skin and damaged skin is necessary as pointed out by Zwart et al., 2004 and Hagens et al., 2007. More studies on gastrointestinal lymphatic uptake and transport and direct toxicological effects on the GIT are required (Lanone and Boczkowski, 2006). Similarly questions such as penetration of placental barrier by nanomaterials would require attention. For such studies suitable in vitro models need to be developed with subsequent in vivo studies. Cellular interactions with certain nanomaterials may not introduce any new pathological conditions, but one cannot ignore novel mechanisms of injury that require special tools, assays and approaches to assess their toxicity. The number of engineered nanomaterials is increasing day-by-day, and it is expected that materials will be more complex and will have unique chemistries; therefore in order to ensure ‘safe’ nanotechnology, ‘Nanotoxicology’ studies would require a standard set of protocols for in vitro, in vivo toxicity (including genotoxicity, teratogenecity), ecotoxicity.

, 2013). The total values have been reported in this study so that comparisons with other studies can be made. Overall it was possible to assign 95th percentile values for 45 of the elements measured in the urine samples (Table 3). The other 16 elements, Ag, Au Bi, Dy, Eu, In, Lu, Nb, Nd, Os, Pr, Sm, Tb, Tm, Y, and Zr all exhibited too high a percentage of results below the limit of detection. This is still useful information because it

is now known that these elements are low in urine samples from occupationally unexposed individuals and are not yet detectable with our existing methodologies. Comparing the data obtained from this studies from with Belgium (Hoet et al., 2013), France (Fréry Dabrafenib mw et al., 2011) and US (NHANES, 2011) studies show that this study reports Obeticholic Acid molecular weight 95th percentiles for 20 elements (B, Br, Ce, Er, Ga, Gd, Ge, Hf, Ho, Ir, La, Rb, Rh, Ru, Sc, Sr, Ta, Th, Ti and Yb) and < LOQ for 14 elements (Ag, Au, Dy, Eu, Lu, Nb, Nd, Os, Pr, Sm, Tb, Tm, Y and Zr) that have not been reported before in any of the other studies. The 95th percentiles established in this study were compared in Table 4 with those obtained from larger European and US based studies which were more comprehensive studies in terms of demographics, sample numbers and sample collection information. Data from a smaller UK based study

(White and Sabbioni, 1998) has also been used to compare this current UK data with. White and Sabbioni published their study in 1998 where urine Olopatadine samples from a similar UK population to this study were measured for thirteen elements as part of a larger EU study (White and Sabbioni, 1998). Comparing the results obtained in this study with those reported in 1998 showed that similar values were obtained for aluminium, molybdenum and nickel. However, slightly lower values were obtained for cobalt, copper, mercury, selenium and thallium and slightly higher values obtained for chromium in this study. In addition, this study showed considerably lower 95th percentile values for cadmium, lead and manganese from those reported in the White and Sabbioni study; with

urinary cadmium decreasing from 2.1 to 0.6 μmol/mol creatinine, urinary lead decreasing from 27.2 to 4.1 μmol/mol creatinine and urinary manganese decreasing from 3.1 to 1.3 μmol/mol creatinine. In the UK leaded petrol was removed from sale by the year 2000 and so it is likely that the decrease in urinary lead levels are as a direct result of this as evidenced by a similar reduction in the lead although at lower concentrations in the US NHANES study, where the levels decreased from 1.26 to 0.86 μmol/mol creatinine from 1999–2000 to 2009–2010 (NHANES, 2011). In comparing the data in Table 4 the 95th percentiles obtained for antimony (Hoet et al., 2013, Fréry et al., 2011 and NHANES, 2011), barium (Hoet et al.

After the simulated SLP data being adjusted to have the observed baseline climate and variation scale, the bias for the present-day median HsHs (see Fig. 17) almost disappears completely, as would be expected. The adjustments also affect the projected changes in HsHs; they attenuate the projected relative changes in general (especially for models driven by ECHAM5), although the pattern of change is maintained. It is not possible to know which projected changes are more reliable, because any type of statistical adjustments has its own limitations. In particular, such adjustments selleck chemicals llc cannot account

for any feedback (e.g., how changes in ocean waves may affect changes in SLP) that may exist in the real world. Similarly, Fig. 18 and Fig. 19 show the present-day climate and projected changes of the 50-year return value of HsHs (z50z50). The model bias patterns (compare upper panels of Fig. 18 with right panel of Fig.

15) are similar to those for the median HsHs, showing in general significant HIR_E overestimation and moderate or low overestimation by the other models. The projected future changes (Fig. 18, lower panels) vary more between models than for MK 1775 the median HsHs, as similarly found by Casas-Prat and Sierra (2013). These results are reasonable because extreme values are normally exposed to a larger uncertainty. Along the Catalan coast, there is a general tendency for z50z50 to decrease or remain constant, except in the northern coast where models RCA_E and HIR_E project an increase. The maximum rate of change

is around not ±20%±20% (larger than for the median HsHs) which is in agreement with the non-linear relation between HsHs and wind for wind-sea states, typically present in stormy conditions, as pointed out by Casas-Prat and Sierra (2013). Very similar spatial patterns and magnitudes of change were obtained by Casas-Prat and Sierra (2013) for the models REM_E and RCA_E. On the contrary, the projected change that they obtained for RCA_H differed from the present study, obtaining a notable increase of z50z50 along almost all E-facing coasts. The adjustments to the simulated SLP data reduce the current z50z50 but not necessarily the model bias. For example, among the five sets of RCM–GCM simulations, HIR_E has the largest positive bias before the adjustments, but it has a negative bias after the adjustments. As for the median HsHs, after applying the adjustments (Fig. 19), the magnitude of change in the z50z50 is slightly reduced, but to much lesser extent than for the median HsHs. Indeed, the projected changes of z50z50 are barely the same (compare Fig. 18 and Fig. 19). This study proposes a statistical method to model near-shore HsHs, at a 3 h and 25 km resolution. This high spatial–temporal resolution is suitable for coastal impact analysis although a complete assessment would have to involve additional wave parameters, such as wave direction (Reguero et al., 2011).

4 or higher,44 which is reached in the terminal ileum. In contrast,

Entocort starts to release budesonide earlier than Budenofalk, and Uceris targets primarily the colon.43 The release profile of the mesalamine formulation used in this study (Salofalk granules) is comparable with that of Apriso,45 and 46 but reveals marked differences from other commercially available mesalamine formulations (eg, Asacol, Pentasa).47 and 48 Given the colonic topography of the disease and the topical action of the test medication, it remains speculative whether the efficacy data achieved in our study can be extrapolated to other budesonide or mesalamine formulations. In summary, our study confirms that budesonide is effective and safe for short-term treatment of collagenous colitis. However, our study has failed to provide evidence of the efficacy of mesalamine

in short-term therapy of collagenous colitis. Additional studies might Selleck Roscovitine be necessary to elucidate the role of mesalamine in microscopic colitis. The authors would like to thank all patients and investigators for their participation and contribution to the study. Our special thanks go to Dr Karl Scheithe for his statistical expertise and to Manuela Pöhlmann (both GKM-Gesellschaft für Therapieforschung mbH, Munich, Germany) for her assistance in conducting the clinical trial. The BUC-60 Study Group: Germany: Matthias Andersen, MEK inhibitor Datteln; Professor Hans-Peter Bartram, Augsburg; Dr Elke Bästlein, Köln-Mühlheim; Günter Böhm, Ludwigshafen; Dr Christian Haferland, Görlitz; Dr Gerhard Heptner, Dresden; Dr Dietrich Hüppe, Herne; Dr Vassilios Kardalinos, Stuhr; Professor Heinz-Jürgen Krammer, Mannheim; Dr Wilfred Landry, Dachau; Dr Albin Lütke, Koblenz; Dr Hans-Joachim Marks, Siegen; Professor Stephan Miehlke, Hamburg; Dr Moritz Müser, Lüdenscheid; Dr Michael Neumeyer, Oldenburg; Dr Kai-Uwe Rehbehn, Solingen; Dr Thomas Schäfer,

Kelkheim; Dr Gerfried Vogel, Neumarkt i. Opf. Denmark: Dr Søren Avnstrøm, Copenhagen; Dr Ole Bonderup, Randers; Dr Henning Glerup, Silkeborg; Dr Óli Jacobsen, Sønderborg; Dr Torben Knudsen, D-malate dehydrogenase Esbjerg; Dr Torben Nathan, Vejle; Dr Terje Rannem, Hvidovre. Lithuania: Dr Gitana Acute, Siauliai; Professor Limas Kupcinskas, Kaunas. Spain: Dr Fernando Fernández-Banares, Terrassa; Dr Javier P. Gisbert, Madrid. United Kingdom: Dr Anthony Shonde, Nottingham. Members of the independent data monitoring committee: Professor Walter Lehmacher (statistician), Professor Volker Groß (gastroenterologist), Professor Wolfgang Kruis (gastroenterologist). “
“Event Date and Venue Details from 2011 11th INTERNATIONAL HCH AND PESTICIDES FORUM 07–09 September Gabala, AZERBAIJAN Web: www.hchforum.com ∗INTEGRATED CONTROL IN PROTECTED CROPS, TEMPERATE CLIMATE 18–22 September Winchester, Hampshire, UK Info: C. Millman, AAB, E-mail: Carol@aab.

As can be seen from Table 3, the results with algorithms

learn more #9 – Baltic_chlor_MODIS and #10 – Baltic_chlor_a_2 (Darecki & Stramski 2004) are better than those obtained with the MODIS_standard but noticeably worse than those using the regional algorithm #8. The results of the comparison of TSM values, calculated from the floating spectroradiometer and MODIS-Aqua data using the regional algorithm (3), with the measured ones are presented in Table 4 (TSM is not a standard product processed from MODIS-Aqua data). As seen from Table 4, retrieval from satellite data, as compared with in situ data, results in an increase in errors and a lowering of the coefficient of determination, but the algorithms work acceptably with satellite data – the averaged ratio of the calculated TSM values to the measured ones is 1.21; the maximum overestimation is > 60%, and the underestimation selleck chemicals is 21%. The errors of the atmospheric correction are analysed in more detail in the next paragraph. As mentioned above, the values of ρ(λ), measured with a floating spectroradiometer,

can be used for validating the atmospheric correction algorithm if the measurements are performed simultaneously with satellite observations. For that, we have the 10 stations considered above. Four comparisons between spectra of the remote sensing reflectance Rrs(λ), measured in situ and retrieved from satellite data of MODIS-Aqua and VIIRS, are shown in Figure 13. It is seen that the atmospheric correction is not ideal – the errors are rather great in

most cases. But from the practical point of view, only the errors for spectral bands of 531 and 547 nm, used in the bio-optical algorithm, are important. But as Figure 13 shows, the errors for these wavelengths are not so high. The effect of errors in the input parameter X on the retrieval of Chl concentration with our regional algorithm #8 can be estimated by using the approximation formula equation(4) Δ(logChl)=ΔX(19.8−85.4X),Δ(logChl)=ΔX(19.8−85.4X),where Δ (log Chl) is the error in log Chl, Δ X – in the X parameter. The errors in the retrieval of different input parameters of the bio-optical algorithms are presented in Table 5. One of our objectives was to estimate the effect of the atmospheric correction Meloxicam using different spectral bands on the derived values of the input parameter; the calculation was performed with MODIS-Aqua and VIIRS satellite data (averaged over 9 pixels). For comparison, the values calculated from the floating spectroradiometer data (11 stations in 2012 and 2013) were taken (‘measured’). Three potential input parameters using different spectral bands of MODIS-Aqua and VIIRS scanners are considered: X1 = log[Rrs(547)/Rrs(531)], X2 = log[Rrs(547)/Rrs(488)] and X3 = log[Rrs(551)/Rrs(486)]. It is seen from Table 5 that the errors increase when using spectral bands of 488 nm (MODIS) or 486 nm (VIIRS) instead of 531 nm.

As neoplasias quísticas, cada vez mais detetadas, têm significativas diferenças no potencial de malignidade. A EE contribui de forma significativa para a sua diferenciação, de acordo com detalhes estruturais e com as características do fluido quístico obtido por PAAF-EE. No entanto, continua incerta a abordagem mais adequada dos pequenos quistos assintomáticos http://www.selleckchem.com/JNK.html e incidentalmente identificados. O desconhecimento da história natural de alguns subtipos de lesões quísticas condicionam a prática clínica e a consensualidade dos algoritmos de abordagem. A EE é mais sensível que a CPRM e igualmente sensível, mas mais segura que a CPRE na deteção de alterações subtis nas formas ligeiras de

pancreatite crónica, contribuindo SD-208 cost de forma decisiva para o

diagnóstico precoce desta entidade, que é desafiante. Representa, além disso, a modalidade com maior acuidade no diagnóstico de microlitíase biliar e pode ter impacto na abordagem de doentes com pancreatite aguda idiopática, permitindo selecionar os doentes que beneficiarão da realização de CPRE. Nos casos de suspeita de PAI a EE pode acrescentar informação útil, ao demonstrar características morfológicas sugestivas e um padrão elastográfico e de captação de contraste típicos da doença, e deve ser utilizada para excluir malignidade por PAAF. As potencialidades da EE neste âmbito poderão vir a ser ampliadas com a aplicação da elastografia e os agentes de contraste. Atualmente, o maior desafio na área da EE pancreática é a expansão do seu potencial terapêutico, a ser abordado na parte III desta sequência de artigos de revisão. Os autores declaram não haver conflito de interesses. “
“O primeiro caso de esofagite eosinofílica (EE)

foi descrito em 1977, sendo que até 1990 a presença de infiltrado eosinofílico foi sinónimo de doença refluxo gastroesofágico (DRGE). Apenas em 1993 a EE foi considerada como entidade clínica distinta. De facto os sintomas de EE são semelhantes aos da DRGE, daí constituir uma importante dificuldade diagnóstica. No entanto, as características patológicas e os sintomas de EE não respondem ao tratamento de supressão ácida. A EE é uma condição clínica caracterizada por: sintomas gastrointestinais, principalmente esofágicos, GNE-0877 associados à presença de densa eosinofilia (≥ a 15 eosinófilos intraepiteliais/CGA) no material de biópsia, com hiperplasia do epitélio escamoso. A ausência de DRGE deve ser descartada por pHmetria ou falta de resposta clínica após tratamento prolongado com elevada dose (> 2 mg/kg/dia) de inibidor da bomba de protões1, 2, 3 and 4. A eosinofilia esofágica não é exclusiva da EE. A sua presença encontra‐se em inúmeras patologias como: DRGE, doenças infeciosas, doenças do tecido conjuntivo, resposta de hipersensibilidade a drogas, síndrome hipereosinofílica, doenças inflamatórias intestinais ou gastroenterite eosinofílica, entre outras.

The colony-stimulating activity of the serum (CSA) from these mice provided information

about the amount of CSF present in the blood after single and Dasatinib repeated stressors. Male BALB/c mice, 6–8 weeks old, were bred at the Campinas University Central Animal Facilities (Centro de Bioterismo, Universidade Estadual de Campinas, Campinas, SP), raised under specific pathogen-free conditions, and matched for body weight before use. Standard chow and water were freely available. Animal experiments were performed in accordance with institutional protocols and the guidelines of the Institutional Animal Care and Use Committee (Protocol Number 1997-1), which follow the recommendations of the Canadian Council on Animal Care (Olfert et al., 1993). The animals were divided into 6 groups of 6 animals each: Controls (C – gavage with vehicle (warm water) for 5 days before bone marrow removal); C. vulgaris (CV – received CV for 5 days before bone marrow removal); single stress/CV + single stress (SST/CV + SST – received vehicle or CV for 5 days before stress protocol); repeated stress/CV + repeated stress (RST/CV + RST – received vehicle or CV for 21 days, i.e., throughout the stress protocol). All experiments were replicated selleck chemicals twice. Single stress consisted of a single 3-h session of restraint stress. Repeated

stress consisted of 21 daily sessions that were 2 h each. Restraint stress was performed in plastic 50 mL conical falcon tubes. A hole was made at one extremity of the tubes for the tail of the mouse, and another hole

was made in the other extremity to enable the mice to breathe. The animals received no food or water during the Mirabegron stress protocol. After being placed into the tubes, the animals were returned to their home cages inside their room. In all groups, femoral marrow was collected 2 h after either the single or the final repeated stress applications. Dried CV algae, a unicellular green algae strain, were kindly provided by Dr. Hasegawa (Research Laboratories, Chlorella Industry Co. Ltd., Fukuoka, Japan). Chemical analysis performed by Hasegawa et al. (1990) revealed that CV contains 44.4 g of protein, 39.5 g of carbohydrates and 15.4 g of nucleic acid in 100 g (dry weight) of whole material. No lipids were detected. CV was prepared in distilled water, and a dosage of 50 mg/kg was given orally by gavage in a 0.2 mL volume/mouse for 5 consecutive days before single stress or for the entire period of repeated stress. The selection of doses for CV was based on previous studies performed in our laboratory (Bincoletto and Queiroz, 1996, Dantas and Queiroz, 1999 and Queiroz et al., 2008). In all groups, femoral marrow was collected 24 h after the final administration of CV. Assays for CFU-GM were performed using bone marrow cells and non-adherent cells collected from LTBMC.

The author greatly appreciates financial support provided by the National Natural Science Foundation of China project, No. 311712494. The author also appreciates the financial support provided by NATP, BARC, Dhaka, Bangladesh. “
“Acid soils are widespread and limit plant production all over the world. They cover 30%–40% of arable land and more than 70% of potential arable land [1]. Constraints to production in acid soils are caused by a combination of lack of essential nutrients, reduced water uptake and mineral toxicity. The initial visual symptom on plant growth is reduced root length [2]. Although approaches such as adding lime, magnesium or calcium to the soil can ameliorate

adverse effects on plant growth, they are both costly and ecologically unsound.

Breeding tolerant cultivars is the most efficient way to cope with soil acidity. Plants vary significantly in acid find more Crizotinib nmr soil tolerance. Variation in acid soil tolerance makes it possible to breed tolerant cultivars. The success of breeding programs relies on an understanding of the physiology, genetics and gene regulatory information of acid soil tolerance. Decades of study have revealed that the tolerance is due to both internal and external mechanisms. The external mechanism, organic acid exudation, is common in higher plants. Various genes and QTL in different species are responsible for different tolerance mechanisms. Molecular markers have been developed to assist gene cloning and to provide useful resources for marker-assisted Tryptophan synthase selection for breeding tolerant cultivars. This paper reviews recent progress in molecular approaches to improve Al tolerance in plants. Soil pH has significant adverse effects on the availability of plant nutrients [3], solubility of toxic heavy metals [4], soil microorganism activity [5], breakdown of root cells [6], and cation exchange capacity in soils [7]. The toxic effects can be classified as morphological and physiological. Both lead to poor plant development and consequently

yield reduction [8]. Acid soil is a worldwide problem (Fig. 1) mainly located in two belts: viz., the northern belt in the cold humid temperate zone covering North America, South Asia and Russia; and the southern belt in humid high rainfall tropical areas including South Africa, South America, Australia and parts of New Zealand [1]. There are 3950 million ha of arable land affected by soil acidity. It affects about 38% of farmland in Southeast Asia, 31% in Latin America, 20% in East Asia, 56% in Sub-Saharan Africa, and parts of North America [9] and [10]. In the Americas, 1616 million ha is affected, mostly in South America. In Australia and New Zealand, 239 million ha of agricultural land is acidic [11]. In China and India, 212 million ha or 12% of agricultural land is classified as acidic. Acid soils not only cause plant production losses, but also affect plant distribution.