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Taxonomic and systematic studies of the woody bamboos are traditionally based on floral morphology, which can cause problems in identification due to the lack of, or infrequent, flowering. Limited studies have been conducted using molecular techniques to overcome this problem. In this study, we used amplified fragment length polymorphisms (AFLPs) to conduct a study of four genera of bamboos (Bambusa, Dendrocalamus, Gigantochloa andThyrsostachys ) in the subtribe Bambusinae. AFLP analysis using eight primer combinations was carried out on 15 species of bamboo. Results showed that AFLPs distinguish the different species by their unique banding patterns. Unique AFLPs were detected in 13 of the 15 species examined. The six Bambusa species examined separated into two clusters. The sixGigantochloa species studied formed a discrete cluster diverging from one of the Bambusa clusters, whileThyrsostachys was less similar to the Bambusa clusters. The similarity index between B. lako and G. atroviolacea was the highest, suggesting that B. lako is more appropriately included within the genusGigantochloa rather than the genus Bambusa. The two Dendrocalamus species examined were very different with D. brandisii clustering within one of the Bambusa clusters and D. giganteus appearing as a very distant species. These results support the contention that critical study of the genus Dendrocalamus is required. The use of AFLPs for identification of particular bamboo species, as well as for the study of relationships within the subtribe, will be useful for industrial purposes and for systematic studies.

Caladiums are popular ornamental plants that have not been well studied at the molecular level. Identification of species within the genus Caladium (Araceae) has been based primarily on morphology. However, the lack of comprehensive references makes identification of Caladium cultivars extremely difficult. Amplified fragment length polymorphism (AFLP) analysis using 17 primer combinations was carried out on two species of Caladium (C. bicolor and C. schomburgkii), including six cultivars of C. bicolor. Results showed that AFLP can be used to distinguish these two species by their unique and different banding patterns. Unweighted Pair Group Method using Arithmetic Averages (UPGMA) permitted cluster analysis of data from 17 selected primer combinations on six cultivars of C. bicolor and one cultivar ofC. schomburgkii . It showed that closely related species can clearly be differentiated and that genetic difference between cultivars can also be established. Unique AFLP molecular markers were detected for all the C. bicolor cultivars used. The use of AFLP has potential for precisely characterizing and identifying particular caladium cultivars as well as for the registration of new cultivars. It will also be useful in future breeding programmes and systematics studies.

Musa L. (Musaceae) is currently separated into five sections (Musa, Rhodochlamys, Callimusa, Australimusa and Ingentimusa) based on chromosome numbers and morphological characters. However, the validation of this classification system is questioned due to the common occurrence of hybridizations across sections and the system not accommodating anomalous species. This study employed amplified fragment length polymorphism (AFLP) in a phenetic examination of the relationships among four sections (material of sect. Ingentimusa was not available) to evaluate whether their genetic differences justify distinction into separate groups. Using eight primer combinations, a total of 276 bands was scored, of which 275 were polymorphic. Among the monomorphic bands, 11 unique markers were identified that revealed the distinct separation of the 11‐chromosome species from the 10‐chromosome species. AFLP results suggest that species of sect. Rhodochlamys should be combined into a single section with species of sect. Musa, and likewise for species of sect. Australimusa to be merged with those of sect. Callimusa.

Shorea (Dipterocarpaceae) is a large genus in which many closely related species often grow together in Southeast Asian lowland tropical rain forests. Many Shorea species share common pollinators, and earlier studies suggested occurrence of interspecific hybridization and introgression. Here, we show morphological and molecular evidence of hybridization between Shorea species. In the census of all the trees of Shorea curtisii, Shorea leprosula, and Shorea parvifolia (>30 cm dbh) within the 164-ha area of Bukit Timah Nature Reserve in Singapore, we found 21 morphologically recognizable hybrid individuals. All of the putative hybrids could be distinguished obviously from the parental species on the basis of vegetative characters. Population genetic analysis of DNA sequences of two nuclear (GapC and PgiC) and chloroplast (trnL-trnF) regions demonstrated that each of the three species had several species-specific mutations. The nuclear sequences of the putative hybrids were heterozygote at all the species-specific sites between two parental species. Hybrid between S. curtisii and S. leprosula was found most, while S. curtisii × S. parvifolia and S. leprosula × S. parvifolia hybrids were also found. Almost no shared polymorphism between populations of the parental species suggests rarity of introgression. The study indicated that natural hybridization between sympatric Shorea species should not be uncommon, but all of the hybrid individuals were F₁, and the post-F₁ hybrids were considerably rare.

Since amplified fragment length polymorphism (AFLP) analysis has proved useful in distinguishing cultivars of Caladium, it was used to assess the status of species of Caladium vs. Xanthosoma, both in tribe the Caladieae, and to reassess the position of Hapaline in the same tribe. AFLP analysis using three primer combinations was carried out on four species of Caladium(C. bicolor, C. humboldtii, C. lindenii and C. schomburgkii). Results showed that AFLP can distinguish between the different species by their unique and different banding patterns. AFLP analysis confirmed that C. humboldtii is a species distinct from C. bicolor and that C. lindenii is a true Caladium species and does not belong to Xanthosoma. UPGMA cluster analysis showed that C. bicolor and C. schomburgkii are most similar and that C. humboldtii is closer to the C. bicolor / C. schomburgkii cluster compared with C. lindenii. Genetic relationships between Caladium, Xanthosoma, Hapaline, Alocasia and Protarum were also examined by AFLP analysis using eight primer combinations. Several useful molecular markers were specific either to Caladium orXanthosoma , so that AFLP can be used to distinguish species of these two genera. Genetic analysis of the genera examined confirms that the Caladieae and Colocasieae tribes are distinct and that Hapaline falls within the tribe Caladieae and that Protarum is most distant from all the genera examined.

A 31-bp variable number of tandem repeats (VNTR) polymorphism of the cystathionine β-synthase (CBS) gene was earlier reported in Caucasians of predominantly European descent and Indo-Caucasoid populations.We report here for the first time, the detection of allele 20, which was absent in Caucasian and Indo-Caucasoid populations, as a common allele present in Singaporean Chinese (6.25%), Indians (11.7%), and Malays (11.5%). Hence, allele 20 might be a specific allele for Asian populations. A relatively common allele 19 found in the Caucasian and Indo-Caucasoid populations (10.4%–10.6%) was absent in the Asian samples of this study. Therefore, allele 19 might be a specific allele for the Caucasian populations. A novel and rare allele 13, which was not reported before in the Caucasian and Indo-Caucasoid populations, was found in 0.5% of Singaporean Chinese as genotype 13/17 heterozygotes. The presence of alleles 13 and 20 were verified by DNA sequencing. There were five new genotypes (13/17, 16/20, 17/20, 18/20 and 20/20) not reported before in the Caucasian and Indo-Caucasoid populations, detected in this study. Nine genotypes (15/18, 16/18, 16/21, 17/19, 18/19, 18/21, 19/19, 19/21 and 21/21) which were present in the Caucasian and/or Indo-Caucasoid populations were absent in this study. Our results showed that CBS 31-bp VNTR polymorphism has a distinct genetic difference in allele and genotype frequencies between the European Caucasians, Indo-Caucasoid and Asian populations.

Photodynamic therapy (PDT), the activation of a photosensitive drug in tumor tissue with light of specific wavelength, has been used effectively to treat certain solid tumors. Though therapeutic responses are encouraging, PDT-mediated oxidative stress can act as an angiogenic switch that ultimately leads to neovascularization and tumor recurrence. This article explores the effect of PDT on angiogenesis in different tumor models. Overexpression of proangiogenic vascular endothelial growth factor, cyclooxygenase-2 and matrix metalloproteases has often been reported post-illumination. Recent clinical studies have demonstrated that inhibiting angiogenesis after chemotherapy and radiotherapy is an attractive and valuable approach to cancer treatment. In this review, we report the effective therapeutic strategy of combining angiogenesis inhibitors with PDT to control and treat tumors.

Background Photodynamic therapy (PDT) is a promising cancer treatment modality that involves the interaction of the photosensitizer, molecular oxygen and light of specific wavelength to destroy tumor cells. Treatment induced hypoxia is one of the main side effects of PDT and efforts are underway to optimize PDT protocols for improved efficacy. The aim of this study was to investigate the anti-tumor effects of PDT plus Erbitux, an angiogenesis inhibitor that targets epidermal growth factor receptor (EGFR), on human bladder cancer model. Tumor-bearing nude mice were assigned to four groups that included control, PDT, Erbitux and PDT plus Erbitux and tumor volume was charted over 90-day period. Results Our results demonstrate that combination of Erbitux with PDT strongly inhibits tumor growth in the bladder tumor xenograft model when compared to the other groups. Downregulation of EGFR was detected using immunohistochemistry, immunofluorescence and western blotting. Increased apoptosis was associated with tumor inhibition in the combination therapy group. In addition, we identified the dephosphorylation of ErbB4 at tyrosine 1284 site to play a major role in tumor inhibition. Also, at the RNA level downregulation of EGFR target genes cyclin D1 and c-myc was observed in tumors treated with PDT plus Erbitux. Conclusion The combination therapy of PDT and Erbitux effectively inhibits tumor growth and is a promising therapeutic approach in the treatment of bladder tumors.

Human endothelial nitric oxide synthase (eNOS) is one isoform of the nitric oxide synthases that are responsible for nitric oxide synthesis from l -arginine. The gene encoding eNOS contains a 27-bp VNTR polymorphism in intron 4. We report here for the first time the presence of a novel allele 3, which was absent in all other populations studied to date, in 1.7% each of Singaporean Indians and Malays. We also detected the presence of a novel genotype 3/5 in 3.4% each of Singaporean Indians and Malays. Allele 6, which was absent in Han Chinese from northern China and Taiwan and was also absent in Indians from the Indian subcontinent, was found in 2.1% of Singaporean Chinese and in 0.3% of Singaporean Indians.

Interleukin-18 (IL-18) plays a key role in autoimmune, inflammatory, and infectious diseases. The IL - 18 gene contains a C to A single nucleotide polymorphism (SNP) at position −607 (C−607A) within the promoter region, which was found to affect the promoter activity and subsequently the protein level of IL-18. We investigated this SNP in a group of healthy Singaporeans and found that CA was the most common genotype and the C allele was more prevalent than the A allele, which was not always the case in other ethnic groups. In addition, Singaporean Chinese were significantly different from Singaporean Indians in both allelic and genotypic distributions. Furthermore, significant deviations from Hardy–Weinberg equilibrium of this SNP were found in all three ethnic groups studied (Chinese, Indians, and Malays) and also in other published literature, suggesting that heterozygotes of this IL - 18 C−607A SNP may have certain selective advantages.