Leonardo Jr Acosta Guevarra

Mr. Leonardo Jr Acosta Guevarra

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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 March 2025 in ZooKeys
Verified
Journal Article
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DADarrell C. Acuña
Darrell C. Acuña
MDMaria Mikaela U. Dumbrique
Maria Mikaela U. Dumbrique
MRMaricel C. Ranido
Maricel C. Ranido
LRLorenz Rhuel P. Ragasa
Lorenz Rhuel P. Ragasa
CNCharles Nylxon C. Noriega
Charles Nylxon C. Noriega
LGLeonardo Jr Acosta Guevarra
Leonardo Jr Acosta Guevarra
Selenobrachys Schmidt, 1999 and Chilocosmia Schmidt & von Wirth, 1992 were considered junior synonyms to Orphnaecus Simon, 1892 without further morphological investigation nor the use of molecular methods of analysis. Herein, the type specimens are reexamined with newly collected samples of currently known Orphnaecus species, including new specimens from Romblon Island, Philippines. Morphological and molecular analyses were performed, utilizing cytochrome oxidase I (COI) and ribosomal genes (12S–tRNA-Val–16S). Synapomorphies in the structure of maxillary lyra, spermathecae, and male palpal morphology were observed in O. philippinus and the Romblon specimen which are distinct from other Orphnaecus species. In addition, lyrate morphology, setae structure on the patella of palp dorsal, and the male palpal organ morphology of O. dichromatus differ from other Orphnaecus species. Cladistic separation observed in molecular phylogenetic analyses supports morphological observations. Our findings suggest that the genus Selenobrachys is distinct from Orphnaecus; hence, the genus Selenobrachys Schmidt, 1999, stat. rev. and its type species Selenobrachys philippinus Schmidt, 1999, comb. rest., are restored and the new species from Romblon Island, Selenobrachys ustromsupasiussp. nov., be identified as the second Selenobrachys species. Furthermore, the genus Chilocosmia Schmidt & von Wirth, 1992, stat. rev. and the original combination of its type species, Chilocosmia dichromata Schmidt & von Wirth, 1992, comb. rest. are restored. Male specimens of S. philippinus and C. dichromata were described for the first time. Insights on the biogeography of Philippine tarantulas are discussed.

2 April 2018 in Infectious Agents and Cancer
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Journal Article
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LGLeonardo Jr Acosta Guevarra
Leonardo Jr Acosta Guevarra
AAAndrea Claudine F. Afable
Andrea Claudine F. Afable
PBPatricia Joyce O. Belza
Patricia Joyce O. Belza
KDKaren Joy S. Dy
Karen Joy S. Dy
SLScott Justin Q. Lee
Scott Justin Q. Lee
PAPia Marie Albano
Pia Marie Albano
The role of Fusobacterium nucleatum Fap2 protein in the development of colorectal cancer has recently been explained. Fap2, when bound to the human inhibitory receptor, TIGIT, inhibits the cytotoxic activity of natural killer (NK) cells against cancer cells, thus, allowing proliferation of the latter eventually leading to tumor growth. The aim of the study was to identify the immunogenicity of a peptide mimotope of the Fap2 protein and to determine the reactivity of colorectal cancer patients’ sera against the mimotope. Immunogenic epitope of the Fap2 protein of F. nucleatum was selected using the B-cell epitope prediction of the Immune Epitope Database and Analysis Resource (IEDB). The immunogenicity of the synthetic peptide mimotope of the Fap2 protein was determined in animal models and reactivity of colorectal cancer patients’ sera against the mimotope was done by indirect ELISA. Results show that the selected peptide mimotope, with sequence TELAYKHYFGT, of the outer membrane protein Fap2 of F. nucleatum is immunogenic. Increase in the absorbance readings of peptide-immunized rabbit sera was observed starting Week 1 which was sustained up to Week 10 in the indirect ELISA performed. Colorectal cancer cases (n = 37) were all reactive in an ELISA-based analysis using the mimotope as the capture antigen. In this study, we identified an immunogenic epitope of the Fap2 protein of the Fusobacterium nucleatum. We demonstrated the reactivity of serum of histopathologically confirmed CRC patients in a peptide-capture indirect ELISA which may serve as proof of concept for the development of CRC diagnostics.

1 January 2021 in Journal of Venomous Animals and Toxins including Tropical Diseases
Verified
Journal Article
Open access
SLSimon Miguel M. Lopez
Simon Miguel M. Lopez
JAJeremey S. Aguilar
Jeremey S. Aguilar
JFJerene Bashia B. Fernandez
Jerene Bashia B. Fernandez
ALAngelic Gayle J. Lao
Angelic Gayle J. Lao
MEMitzi Rain R. Estrella
Mitzi Rain R. Estrella
LSLibrado A. Santiago
Librado A. Santiago
Spider venom is a rich cocktail of neuroactive compounds designed to prey capture and defense against predators that act on neuronal membrane proteins, in particular, acetylcholinesterases (AChE) that regulate synaptic transmission through acetylcholine (ACh) hydrolysis - an excitatory neurotransmitter - and beta-secretases (BACE) that primarily cleave amyloid precursor proteins (APP), which are, in turn, relevant in the structural integrity of neurons. The present study provides preliminary evidence on the therapeutic potential of Phlogiellus bundokalbo venom against neurodegenerative diseases. Spider venom was extracted by electrostimulation and fractionated by reverse-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption ionization-time flight mass spectrometry (MALDI-TOF-MS). Neuroactivity of the whole venom was observed by a neurobehavioral response from Terebrio molitor larvae in vivo and fractions were screened for their inhibitory activities against AChE and BACE in vitro. The whole venom from P. bundokalbo demonstrated neuroactivity by inducing excitatory movements from T. molitor for 15 min. Sixteen fractions collected produced diverse mass fragments from MALDI-TOF-MS ranging from 900-4500 Da. Eleven of sixteen fractions demonstrated AChE inhibitory activities with 14.34% (± 2.60e-4) to 62.05% (± 6.40e-5) compared with donepezil which has 86.34% (± 3.90e-5) inhibition (p > 0.05), while none of the fractions were observed to exhibit BACE inhibition. Furthermore, three potent fractions against AChE, F1, F3, and F16 displayed competitive and uncompetitive inhibitions compared to donepezil as the positive control. The venom of P. bundokalbo contains compounds that demonstrate neuroactivity and anti-AChE activities in vitro, which could comprise possible therapeutic leads for the development of cholinergic compounds against neurological diseases.

11 November 2019 in Microbiology and Immunology
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Journal Article
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LGLeonardo Jr Acosta Guevarra
Leonardo Jr Acosta Guevarra
KBKathleen Joyce O. Boado
Kathleen Joyce O. Boado
FCFidel Bryan B. Ceñidoza
Fidel Bryan B. Ceñidoza
MIMa. Rio Lauren M. Imbao
Ma. Rio Lauren M. Imbao
MSMichelle Joy G. Sia
Michelle Joy G. Sia
LDLeslie Michelle M. Dalmacio
Leslie Michelle M. Dalmacio

28 January 2021 in Research Square
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EMEdrienne Myenna Magat
Edrienne Myenna Magat
GBGregg Austine Balanag
Gregg Austine Balanag
ACAna Maria Cariño
Ana Maria Cariño
AFAllan Fellizar
Allan Fellizar
TSTeresa Sy-Ortin
Teresa Sy-Ortin
LGLeonardo Jr Acosta Guevarra
Leonardo Jr Acosta Guevarra
BACKGROUND: The role of certain gut microbes in the development of colorectal cancer has recently been understood. In our previous work, we have reported the reactivity of serum collected from CRC patients to peptide mimotopes of bacterial antigens associated with the development of CRC, hence, their potential in its detection. Here, we evaluate the diagnostic parameters of an anti- Clostridioides difficile toxin B (tcdB) peptide mimotope IgG and IgA antibody-capture enzyme-linked immunosorbent assay (ELISA) in the detection of CRC.METHODS: Prediction of the immunogenic epitopes of tcdB was made using the in silico B-cell epitope mapping tools available at the Immune Epitope Database and Analysis Resources (IEDB). Synthetic peptide analogs of the predicted epitopes which were used in the immunoassays were synthesized and purchased from Genscript (New Jersey, USA). Presence of anti-peptide IgG and IgA from serum collected from patients diagnosed with colorectal cancer were detected by a peptide antibody-capture indirect ELISA protocol developed in this study. Diagnostic parameters were computed. RESULTS: The amino acid position 1465 to 1474 of the reported sequence of tcdB (PDB Accession No. AGG91641.1) was predicted to be immunogenic. The peptide antibody-capture ELISA developed in this study gave diagnostic specificities of 94.9% and 97.4%, positive predictive values (PPV) of 86.6% and 93.3%, and likelihood ratios of 6.5 and 14.0 for IgG and IgA, respectively. Our results show the potential of the immunoassay designed in ruling in possibility of CRC during diagnosis.

1 July 2025
Verified
Journal Article
Closed access
LGLeonardo Jr Acosta Guevarra
Leonardo Jr Acosta Guevarra
CRCydee Marie V. Ramones
Cydee Marie V. Ramones
MSMyla R. Santiago-Bautista
Myla R. Santiago-Bautista
LDLeslie Michelle M. Dalmacio
Leslie Michelle M. Dalmacio