BIOTEC Central Research Unit

Pathum Thani, Thailand

BIOTEC Central Research Unit

Pathum Thani, Thailand
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Sritakae A.,BIOTEC Central Research Unit | Praseartkul P.,BIOTEC Central Research Unit | Cheunban W.,BIOTEC Central Research Unit | Miphokasap P.,BIOTEC Central Research Unit | And 9 more authors.
Aerobiologia | Year: 2011

Papaya is an economically important plant in Thailand for domestic consumption and export. However, papaya is extremely susceptible to disease caused by the papaya ring spot virus. Although transgenic papaya has been developed, commercial cultivation of transgenic plants in Thailand is still illegal. One concern is cross-pollination to conventional varieties. In this study, windborne-pollen dispersion of papaya (Carica papaya L.) was investigated using geographic information systems (GIS) and remotely sensed data. Pollen traps were placed around a papaya plot in eight geographic directions, with radiuses varying from 5 to 900 m from the plot. Pollen counts were made for 12 different dates, and data were input into a GIS database. The distribution of pollen and its relation to land use were analyzed using land use data obtained from Quickbird imagery acquired during 2007. Comparative analyses of pollen dispersal, wind direction, and speed were made using data collected from a micro-climatic station set up at a papaya plot. The furthest distance from the plot that pollen was found was at 0.9 km, a distance at which only 1 pollen grain was found. The number of pollen grains carried by wind decreased as distance increased. The direction of dispersal was not in accordance with wind direction data. Most pollen grains were found in agricultural areas and bare land. The total number of pollen grains found in exposed areas was considerably higher than the total found in areas sheltered by dense tree lines. © 2011 Springer Science+Business Media B.V.

Brown C.,University of Edinburgh | Brown C.,University of St. Andrews | Burslem D.F.R.P.,University of Aberdeen | Illian J.B.,University of St. Andrews | And 31 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2013

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed.We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatiblewith neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences.We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity. © 2013 The Author(s) Published by the Royal Society. All rights reserved.

Kositcharoenkul N.,Kasetsart University | Kositcharoenkul N.,Center for Agricultural Biotechnology PERDO CHE | Chatchawankanphanich O.,BIOTEC Central Research Unit | Bhunchoth A.,BIOTEC Central Research Unit | And 2 more authors.
Plant Pathology | Year: 2011

A single-tube nested PCR was developed for detection of Xanthomonas citri subsp. citri (Xcc), the causal agent of citrus canker disease. The assay targets the pthA gene of Xcc and utilizes different annealing temperatures for the two primer pairs. It reliably detected as few as 1·0×102Xcc cells, and was unaffected by the presence of PCR inhibitors. It was 10-fold and 8500-fold more sensitive than standard PCR and ELISA, respectively. Increased sensitivity was also achieved via the use of a washing method for DNA extraction, as opposed to direct extraction from leaf tissue. When evaluated for Xcc detection in 90 samples collected from affected pomelo orchards, the single-tube nested PCR was superior to standard PCR, detecting the pathogen in 67 vs. 54 samples. It was also able to detect Xcc from samples with and without symptoms. This assay can be used as a rapid and sensitive technique for routine Xcc detection in field samples for surveillance of citrus canker. © 2010 The Authors. Plant Pathology © 2010 BSPP.

Washio K.,Hokkaido University | Lim S.P.,Sunway University | Roongsawang N.,BIOTEC Central Research Unit | Morikawa M.,Hokkaido University
Bioscience, Biotechnology and Biochemistry | Year: 2011

Arthrofactin is a biosurfactant produced by Pseudomonas sp. MIS38. We have reported that transposon insertion into spoT (spoT::Tn5) causes moderate accumulation of guanosine 3′,5′-bispyrophosphate (ppGpp) and abrogates arthrofactin production. To analyze the linkage of SpoT function and ablation of arthrofactin production, we examined the spoT::Tn5 mutation. The results showed that spoT::Tn5 is not a null mutation, but encodes separate segments of SpoT. Deletion of the 3′ region of spoT increased the level of arthrofactin production, suggesting that the C-terminal region of SpoT plays a suppressive role. We evaluated the expression of a distinct segment of SpoT. Forced expression of the C-terminal region that contains the ACT domain resulted in the accumulation of ppGpp and abrogated arthrofactin production. Expression of the C-terminal segment also reduced MIS38 swarming and resulted in extensive biofilm formation, which constitutes the phenocopy of the spoT::Tn5 mutant.

Liu J.-K.,Mae Fah Luang University | Gareth Jones E.B.,BIOTEC Central Research Unit | Chukeatirote E.,Mae Fah Luang University | Bahkali A.H.,King Saud University | And 2 more authors.
Mycotaxon | Year: 2011

During studies of palm fungi, a new Lignincola species was found in Thailand. It differs from other members of the genus in ascospore dimensions and the occurrence of its ascomata on the adhesive pad of a marine invertebrate. Lignincola conchicola is described and illustrated, and a key to Lignincola species is provided. The palm Phoenix is a new substratum for marine fungi. © 2011 Publishing Technology.

Liu J.-K.,Mae Fah Luang University | Chomnunti P.,Mae Fah Luang University | Cai L.,CAS Institute of Microbiology | Phookamsak R.,Mae Fah Luang University | And 5 more authors.
Sydowia | Year: 2010

Palm fungi are a taxonomically diverse group. Recent collections of fungi from palms in northern Thailand resulted in the discovery of a new species of Neodeightonia, herein described as N. palmicola. This new species is distinct in having hyaline, aseptate ascospores surrounded by a remarkable sheath. This study compares this new species with related taxa of Botryosphaeria and Neodeightonia using morphological and molecular characteristics. Sequence data show our species is more closely related to Neodeightonia subglobosa (the type species of the genus) than to Botryosphaeria species. Morphological and molecular features of the new species are described.

Kantha T.,Chiang Mai University | Chaiyasut C.,Chiang Mai University | Kantachote D.,Prince of Songkla University | Sukrong S.,Chulalongkorn University | Muangprom A.,BIOTEC Central Research Unit
African Journal of Microbiology Research | Year: 2010

Soil samples from organic saline paddy fields from 14 provinces of the northeast region of Thailand were collected and used for isolating photosynthetic bacteria (PB) prepared as a Soil and Straw Products (SSPs). PB from these SSPs were further grown in double strength G5 broth under microaerobic-light conditions before purification. A total of 130 isolates were then screened for growth in G5 broth under microaerobic-dark conditions for 24 h and 15 isolates were further selected by secondary screening in G5 broth under microaerobic-light conditions for 24 h. Four isolates (tk35, tk85, tk103 and tk123) were selected and all were identified as Rhodopseudomonas palustris based on their 16S rRNA gene. After incubation in SSP for 4 weeks with microaerobic-dark conditions, all SSPs had pH values in a range of 5.33 -7.17 and electrical conductivity (EC) values were between 3.02-12.93 dS/m. It was also found that the 5-aminolevulinic acid (ALA) content increased with time to achieve levels of 2.95, 2.94, 2.95 and 2.96 mM, from strains tk35, tk85, tk103 and tk123, respectively. The results indicate that SSP containing selected PB could produce ALA and this could be practically applied to organic saline paddy fields and increase growth and yields of rice. © 2010 Academic Journals.

Piccinato C.A.,University of Wisconsin - Madison | Sartori R.,University of Wisconsin - Madison | Sartori R.,University of Sao Paulo | Sangsritavong S.,University of Wisconsin - Madison | And 6 more authors.
Journal of Dairy Science | Year: 2010

Some studies have reported improved reproductive performance with dietary fat supplementation. This study examined effects of fatty acids with different lengths, or desaturation, or both, on metabolism of estradiol (E2) and progesterone (P4) in bovine liver slice incubations (experiments 1 and 2) and in vivo (experiment 3). In experiment 1, effects of fatty acids C16:0 (palmitic acid), C16:1 (palmitoleic acid), C18:1 (oleic acid), and C18:3 (linolenic acid) were evaluated at 30, 100, and 300 μM on P4 and E2 metabolism in vitro. In experiment 2, stearic acid (C18:0) and C18:3 were evaluated in the same incubation conditions. In experiment 1, all of the fatty acids had some significant inhibitory effect on metabolism of P4, E2, or both (300 μM C16:0 on E2; 100 μM C16:1 on E2; 300 μM C16:1 on both P4 and E2; 300 μM C18:1 on P4; and 100 and 300 μM C18:3 on both P4 and E2). In experiment 2, C18:3 (100 and 300 μM) but not C18:0 decreased P4 and E2 metabolism. Overall, the most profound increase (∼60%) in half-life of P4 and E2 was observed with incubations of 300 μM C18:3 in both in vitro experiments. Based on these in vitro results, in experiment 3 linseed oil (rich in C18:3) was supplemented into the abomasum and acute effects on metabolism of E2 and P4 were evaluated. Cows (n=4) had endogenous E2 and P4 minimized (corpus luteum regressed, follicles aspirated) before receiving continuous intravenous infusion of E2 and P4 to analyze metabolic clearance rate for these hormones during abomasal infusion of saline (control) or 70. mL of linseed oil every 4. h for 28. h. Linseed oil infusion increased C18:3 in plasma by 46%; however, metabolic clearance rate for E2 and P4 were similar for control cows compared with linseed-treated cows. Thus, in vitro experiments indicated that E2 and P4 metabolism can be inhibited by high concentrations of C18:3. Nevertheless, in vivo, linseed oil did not acutely inhibit E2 and P4 metabolism, perhaps because insufficient C18:3 concentrations (increased to ∼8 μM) were achieved. Further research is needed to determine the mechanism(s) of fatty acid inhibition of P4 and E2 metabolism and to discover practical methods to mimic this effect in vivo. © 2010 American Dairy Science Association.

McConkey K.R.,E 64 Sainikpuri | Brockelman W.Y.,BIOTEC Central Research Unit | Brockelman W.Y.,Mahidol University
Ecology | Year: 2011

Plant species with generalized dispersal mutualisms are considered to be robust to local frugivore extinctions because of redundancy between dispersal agents. However, real redundancy can only occur if frugivores have similar foraging and ranging patterns and if fruit is a limiting resource. We evaluated the quantitative and qualitative contributions of seed dispersers for an endochorus mast-fruiting species, Prunus javanica (Rosaceae) in Khao Yai National Park, Thailand, to evaluate the potential redundancy of dispersers. Data were collected from tree watches, seed/fruit traps, and seed transects under and away from fruiting trees, feeding and seed deposition by gibbons (Hylobates lar), and evaluations of seed and firstyear seedling survival. We identified three clusters of dispersers within the network. Most (.80%) frugivore species observed were small birds and squirrels that were not functional dispersers, dropping most seeds under or very near the tree crown, where seedling survival was ultimately nil. Monkeys (Macaca leonina) were low-quality, short-range dispersers, but they dispersed large numbers of seeds and were responsible for 67% of surviving first-year seedlings. Gibbons and Oriental Pied Hornbills (Anthracoceros albirostris) handled few fruits, but they provided the highest quality service by carrying most seeds away from the canopy to medium and long distances, respectively. Although there was overlap in the deposition patterns of the functional dispersers, they displayed complementary, rather than redundant, roles in seed dispersal. Satiation of all functional dispersers further limited their capacity to ''replace'' one another. Redundancy must be evaluated at the community level because each type of disperser may shift to different species in the non-masting years of P. javanica. Our results underscore the need for research on broader spatial and temporal scales, which combines studies of dispersal and plant recruitment, to better understand mechanisms that maintain network stability. © 2011 by the Ecological Society of America.

Washio K.,Hokkaido University | Lim S.P.,University of California at Berkeley | Roongsawang N.,BIOTEC Central Research Unit | Morikawa M.,Hokkaido University
Bioscience, Biotechnology and Biochemistry | Year: 2010

Pseudomonas sp. MIS38 produces an effective biosurfactant named arthrofactin, which is a cyclic lipopeptide synthesized by a mega complex composed of three nonribosomal peptide synthetases. In order to gain insight into the control mechanism of arthrofactin production, a Tn5 mutant library was constructed and screened for arthrofactin-deficient mutants. Along with a number of mutations that occurred in the arthrofactin synthetase operon, three other mutants harbored distinct Tn5 insertions in the genes encoding SyrF-like protein (arfF), heat shock protein (htpG), and (p)ppGpp synthetase/hydrolase (spoT). Epistasis analyses revealed that spoT functions early in the arthrofactin production pathway. We also found that spoT affects MIS38 swarming, biofilm formation, and the cell morphology.

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