Nanette Hope Sumaya

The bioluminescence of entomopathogenic bacteria of the genus Photorhabdus was considered to be constitutive. However, it has recently been shown that under heat shock conditions, lux-operon is activated in Photorhabdus temperata cells. In the present study, bioluminescence thermoactivation was investigated in two isolated strains, Photorhabdus hainanensis FV2401 and P. temperata FV2402. The luminescence of the more thermotolerant P. hainanensis cells was activated at higher temperatures than that of P. temperata. At the maximum induction temperatures of 37 °C for FV2401 and 34 °C for FV2402, higher bioluminescence activation was observed in FV2401, whereas the increase in lux-genes mRNA levels was approximately the same in both strains. In P. hainanensis, elevated temperatures also affected the expression of the hexA, madB, and csrB genes, which are indirectly involved in luminescence in Photorhabdus. The heat-activated lux-operon promoter in P. hainanensis and P. temperata was determined. This is a σ⁷⁰-dependent promoter that differs in its distance from the luxC start codon. When promoter variants with or without the 5′-UTR mRNA were transferred to the heterologous Escherichia coli system, heat activation of luminescence was retained in constructs containing only the promoter and was independent of σ³² and σ^E, whereas constructs with the 5′-UTR exhibited repression of luminescence following thermoactivation. The obtained data on the temperature-induced promoter of the lux-operon can broaden understanding of the ecological and biological functions of Photorhabdus bioluminescence under heat shock conditions and provide a basis for the development of novel biosensors.

Trichostrongylid nematodes are globally distributed gastrointestinal parasites of major veterinary and, in some cases, zoonotic importance. Accurate identification often requires an integrative approach because morphology alone may be compromised by specimen damage, cryptic diversity, and dimorphic species complexes. In the Philippines previous work has been largely limited to coproscopy, with no published DNA-based studies on adult trichostrongylids or scanning electron microscopy (SEM) documentation. Here, we provide an integrative characterization of Haemonchus contortus and Trichostrongylus axei recovered from a single goat in Mindanao, Philippines, in 2023. Identification was based on light microscopy, SEM, morphometry, and sequence data from the cox1 and ITS regions. Phylogenetic analyses and a haplotype network for H. contortus placed the Philippine material within a widely distributed lineage complex with weak geographic structuring. Because the study is based on parasites from a single host, the findings should be interpreted as a taxonomic and faunistic record rather than evidence for broader epidemiological or population-level patterns. This study provides the first molecular record of trichostrongylid nematodes from the Philippines and the first SEM-based documentation of H. contortus in the country. Broader sampling is needed to assess parasite diversity, distribution, genetic variation, and potential veterinary and public health relevance nationwide.

Recent mycological surveys in Northern Mindanao, Philippines, have uncovered two morphologically distinct, previously undescribed species of Ophiocordyceps ( Hypocreales : Ophiocordycipitaceae ). Using an integrative framework that combines morphological assessment with multilocus phylogenetics (nrSSU, nrLSU, tef1‐α , rpb1 , rpb2 ), we propose Ophiocordyceps rogongonensis sp. nov. and Ophiocordyceps xylostellae sp. nov. Phylogenetic analyses place O. rogongonensis within the core O. sobolifera clade as sister to O. hydrangea . It is distinguished by its deep reddish‐brown coloration at maturity, slender obclavate stroma resembling chili peppers, bacilliform perithecia, and ascospores breaking readily at their septa into pairs of shorter part‐spores. This is the first cicada‐infecting Ophiocordyceps reported in the Philippines. In contrast, O. xylostellae forms a distinct lineage in the O. elongata clade as sister to O. fenggangensis . It is distinguished by its type host, multiple short synnemata, long acicular‐tipped phialides, and fusiform, ellipsoidal, to subglobose, mucous‐sheathed conidia and represents the first Hirsutella ‐type entomopathogen described from Plutella xylostella (diamondback moth) to date. These discoveries emphasize the underexplored fungal diversity of tropical Philippine ecosystems, expanding the knowledge of Ophiocordycipitaceae in Southeast Asia and providing a foundation for future entomopathogenic fungi research in the Philippines.

Trichostrongylid nematodes are globally distributed gastrointestinal parasites of major veterinary and, in some cases, medical importance. Among them, Haemonchus contortus is especially important as a highly pathogenic haematophagous species. Reliable diagnosis of trichostrongylids often requires an integrative approach because specimen damage, cryptic diversity, dimorphic species complexes, and possible hybridization may compromise identification based on morphology alone. In the Philippines, and particularly in Mindanao, previous work has been restricted largely to coproscopy, with no published studies on adult trichostrongylids using DNA-based methods or scanning electron microscopy (SEM). Here, we present an integrative characterization of H. contortus and Trichostrongylus axei recovered from a goat in Mindanao, Philippines, in 2023. Identification was based on light microscopy, SEM, morphometry with descriptive statistics, and sequence data from the CoxI and ITS regions. Phylogenetic analyses and a haplotype network for H. contortus indicated that the Philippine material belongs to a widely distributed lineage complex showing weak geographic structuring. In broadly distributed nematodes of small ruminants, the geographic origin of individual genotypes may therefore be difficult to infer from locality alone, as global host movements can facilitate admixture among parasite lineages. This study provides the first molecular record of trichostrongylid nematodes from the Philippines and the first SEM-based documentation of H. contortus in the country. These findings confirm the presence of economically important gastrointestinal nematodes in Philippine small ruminants and underscore the value of integrative diagnosis for accurate species delimitation. Broader sampling is needed to clarify parasite diversity, distribution, and genetic variation across the country.

Traditional medicinal knowledge remains an important source of healthcare for many communities in the Philippines, particularly in rural and Indigenous areas where access to modern treatments is limited. In this context, Vaccinium uliginosum (locally known as Ayusip), a plant used by indigenous peoples in Tublay, Benguet Province, has drawn interest due to its reported therapeutic applications for ailments such as cough, flu, and even cancer. This study investigates the cytotoxic properties of Ayusip, aiming to provide scientific validation for its traditional use and assess its potential as a source of bioactive compounds for cancer treatment. Leaves of V. uliginosum were collected, identified, and subjected to methanol extraction, with further partitioning using n-hexane and ethyl acetate. Phytochemical analysis indicated high levels of flavonoids, saponins, steroids, and tannins. Quantification showed significant phenolic (24.58±8.11 GAE mg/g) and flavonoid (121.38±14.04 QE mg/g) content. Antioxidant testing (DPPH assay) revealed strong activity (97.86±1.33%) at 25 mg/mL. The cytotoxicity of V. uliginosum was assessed against normal embryonic lung fibroblasts (MRC-5) and cancer cell lines HCT-116 (colorectal) and A549 (lung adenocarcinoma) using the MTT assay. Results showed that only the n-hexane extract was toxic to MRC-5 cells at high concentrations, while methanol and n-hexane extracts were highly cytotoxic to HCT-116 cells. In A549 cells, only n-hexane extract exhibited cytotoxicity. These findings suggest that V. uliginosum has promising cytotoxic effects, particularly at higher concentrations, with notable activity against HCT-116 cells. Interestingly, its cytotoxicity is biphasic: high concentrations induce maximum toxicity, whereas lower concentrations may encourage cell proliferation. Overall, this study offers insights into the cytotoxic potential of V. uliginosum, a traditionally used plant among Benguet’s IPs, highlighting its potential medicinal value.

Entomopathogenic nematodes (EPNs) of the genera Heterorhabditis and Steinernema are widely used as biological control agents (BCAs) against agricultural insect pests. Recently, nematodes from the genus Oscheius have shown potential as candidates for biological control agents. In this study, two nematode populations from the agricultural fields in Bukidnon, Philippines, were isolated using the traditional insect soil baiting technique with superworm (Zophobas morio). Through morphological, morphometrical, and molecular analyses, these nematodes, labelled as BRT2 and CSS4, were identified as Oscheius colombianus, the country's first record of the species. Preliminary laboratory assays were conducted to evaluate the efficacy of the isolated nematodes against Z. morio larvae. The results showed that the isolate BRT2 exhibited higher efficacy than the isolate CSS4. Isolate BRT2 was tested against different developmental stages of Spodoptera litura and effectively controlled all stages. The fourth and fifth instar larvae showed the highest susceptibility within 72–96 h post‐inoculation at various test concentrations (500, 300 and 100 IJs/larvae). However, 2‐day‐old pupae had the lowest mortality rate among all treatments, with the commercially available Steinernema siamkayai Thai strain (SST1) serving as the standard control. This study highlights the potential of locally isolated nematodes as biocontrol agents for combating different stages of S. litura. The findings contribute to the growing research on EPNs and their applications in agricultural pest management.