Genome drafts of Pseudogracilibacillus spp. from soil and sediment of Mount Makiling, a dormant volcano in the Philippines.

We present the draft whole-genome sequences of Pseudogracilibacillus spp. isolated from the soils and sediments of Sipit Creek located at Mount Makiling, a dormant volcano in the southern part of Luzon Island, Philippines. This Pseudogracilibacillus spp. genome report extends the body of knowledge on a lesser-known genus of Bacillaceae.

Pentamycin Biosynthesis in Philippine Streptomyces sp. S816: Cytochrome P450-Catalyzed Installation of the C-14 Hydroxyl Group.

Pentamycin is a polyene antibiotic, registered in Switzerland for the treatment of vaginal candidiasis, trichomoniasis, and mixed infections. Chemical instability has hindered its widespread application and development as a drug. Here, we report the identification of Streptomyces sp. S816, isolated from Philippine mangrove soil, as a pentamycin producer. Genome sequence analysis identified the putative pentamycin biosynthetic gene cluster, which shows a high degree of similarity to the gene cluster responsible for filipin III biosynthesis. The ptnJ gene, which is absent from the filipin III biosynthetic gene cluster, was shown to encode a cytochrome P450 capable of converting filipin III to pentamycin. This confirms that the cluster directs pentamycin biosynthesis, paving the way for biosynthetic engineering approaches to the production of pentamycin analogues. Several other Streptomyces genomes were found to contain ptnJ orthologues clustered with genes encoding polyketide synthases that appear to have similar architectures to those responsible for the assembly of filipin III and pentamycin, suggesting pentamycin production may be common in Streptomyces species.

Draft Genome Sequence of Insecticidal Streptomyces sp. Strain PCS3-D2, Isolated from Mangrove Soil in Philippines.

A draft genome sequence of a Streptomyces sp. isolated from mangrove soil in Cebu, Philippines, is described here. This isolate produced compounds with contact insecticidal activity against important corn pests. The genome contains 7,479,793 bp (in 27 scaffolds), 6,297 predicted genes, and 29 secondary metabolite biosynthetic gene clusters.

Comparative binding of Cry1Ab and Cry1F Bacillus thuringiensis toxins to brush border membrane proteins from Ostrinia nubilalis, Ostrinia furnacalis and Diatraea saccharalis (Lepidoptera: Crambidae) midgut tissue.

The European (Ostrinia nubilalis Hübner) and Asian corn borers (Ostrinia furnacalis Guenée) are closely related and display similar sensitivity to Cry1 toxins. In this study, we compared the binding patterns of Cry1Ab and Cry1F toxins between both Ostrinia spp., as well as the expression of putative cadherin- and aminopeptidase-N (APN)-like protein receptors. Additionally, cDNA sequences of these putative toxin receptors from both Ostrinia species were compared. Ligand blots for both species indicated a similar binding pattern for Cry1Ab with the strongest immunoreactive band at 260 kDa in both species. In addition, similar expression of the putative cadherin- and APN-like protein receptors were observed at 260 and 135 kDa, respectively. A high degree of similarity (98% amino acid sequence identity) of cDNA sequences for both putative receptor sequences was observed. The Cry1F ligand blot revealed that O. furnacalis and O. nubilalis BBMV exhibited slightly different binding patterns, with strong binding to putative proteins at 150 and 140 kDa, respectively. Both proteins appeared to also bind Cry1Ab, although the signal intensity was much reduced with Cry1Ab. O. furnacalis showed an additional but weaker band at 210 kDa relative to the 150 kDa band. Diatraea saccharalis (Fabricius), which was used as an outgroup species, exhibited different binding patterns than either Ostrinia species, with both Cry1Ab and Cry1F toxins binding to a 210 kDa protein. These results support the previous experiments indicating that O. nubilalis and O. furnacalis share similar patterns of susceptibility to Cry toxins.

Postcommercialization monitoring of the long-term impact of Bt corn on non-target arthropod communities in commercial farms and adjacent riparian areas in the Philippines.

A 4-yr on-farm study was conducted in the Philippines between 2006 and 2009 to determine if there are any long-term impacts of Bt corn on the arthropod community on commercial farms and in adjacent riparian areas. Arthropod counts were gathered by visual inspection of corn plants in three pairs of commercial farms and by sweep sampling in riparian sites close by. Sampling showed that species composition between Bt and non-Bt corn and between riparian areas adjacent to Bt or non-Bt corn were similar. Principal response curves and analysis of variance showed that there were no adverse effects of Bt corn on the abundance of natural enemies either in crops or adjacent riparian sites. The frequently observed natural enemies in Bt corn were the predatory coccinellid beetle, Micraspis discolor (F.) and spiders (Araneae). Arthropod diversity was similar 1) in Bt- and non-Bt corn and 2) the adjacent riparian areas. Taken together, the two parts of this study show that Bt corn does not have any long-term adverse effect on arthropod communities in corn (Zea mays L.) or in adjacent riparian ecosystems. The methods and results described in this study will be useful to Philippine government regulators in making recommendations and policy guidelines related to monitoring for environmental effects of transgenic crops. The current study did not attempt to demonstrate the direct exposure of arthropods in riparian sites to transgenic Cry1Ab protein that might come from adjacent Bt corn fields; that would require different experimental methods but the current study suggests such effects are unlikely.

Bacillus thuringiensis delta-endotoxin binding to brush border membrane vesicles of rice stem borers.

The receptor binding step in the molecular mode of action of five delta-endotoxins (Cry1Ab, Cry1Ac, Cry1C, Cry2A, and Cry9C) from Bacillus thuringiensis was examined to find toxins with different receptor sites in the midgut of the striped stem borer (SSB) Chilo suppressalis (Walker) and yellow stem borer (YSB) Scirpophaga incertulas (Walker) (Lepidoptera: Pyralidae). Homologous competition assays were used to estimate binding affinities (K(com)) of (125)I-labelled toxins to brush border membrane vesicles (BBMV). The SSB BBMV affinities in decreasing order was: Cry1Ab = Cry1Ac > Cry9C > Cry2A > Cry1C. In YSB, the order of decreasing affinities was: Cry1Ac > Cry1Ab > Cry9C = Cry2A > Cry1C. The number of binding sites (B(max)) estimated by homologous competition binding among the Cry toxins did not affect toxin binding affinity (K(com)) to both insect midgut BBMVs. Results of the heterologous competition binding assays suggest that Cry1Ab and Cry1Ac compete for the same binding sites in SSB and YSB. Other toxins bind with weak (Cry1C, Cry2A) or no affinity (Cry9C) to Cry1Ab and Cry1Ac binding sites in both species. Cry2A had the lowest toxicity to 10-day-old SSB and Cry1Ab and Cry1Ac were the most toxic. Taken together, the results of this study show that Cry1Ab or Cry1Ac could be combined with either Cry1C, Cry2A, or Cry9C for more durable resistance in transgenic rice. Cry1Ab should not be used together with Cry1Ac because a mutation in one receptor site could diminish binding of both toxins.