Relationship between rainfall and Aedes larval population at two insular sites in Pulau Ketam, Selangor, Malaysia

Two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) were selected to study the population dynamics of Aedes aegypti and Aedes albopictus mosquitoes, vectors of dengue and chikungunya infections. Ovitrap surveillance was conducted between October 2007 and October 2008. There was an inverse negative association between ovitrap index and rainfall at the time of collection, probably because rainfall increased the number of available oviposition sites. Rainfall and ovitrap index were positively associates the 25th day after rainfall occurred. A minor, second peak was observed from the 38th to the 42nd day. The first peak was consistent with the minimum 18-day period between the hatching of eggs to the first oviposition. The second minor peak could be due to the second gonotrophic cycle of the female mosquitoes. Rainfall is an important environmental factor associated with Aedes breeding at the study sites.

In silico evaluation of bisphosphonates identifies leading candidates for SARS-CoV-2 RdRp inhibition

The novel coronavirus disease (COVID-19) pandemic has resulted in 777 million confirmed cases and over 7 million deaths worldwide, with insufficient treatment options. Innumerable efforts are being made around the world for faster identification of therapeutic agents to treat the deadly disease. Post Acute Sequelae of SARS-CoV-2 infection or COVID-19 (PASC), also called Long COVID, is still being understood and lacks treatment options as well. A growing list of drugs are being suggested by various in silico, in vitro and ex vivo models, however currently only two treatment options are widely used: the RNA-dependent RNA polymerase (RdRp) inhibitor remdesivir, and the main protease inhibitor nirmatrelvir in combination with ritonavir. Computational drug development tools and in silico studies involving molecular docking, molecular dynamics, entropy calculations and pharmacokinetics can be useful to identify new targets to treat COVID-19 and PASC, as shown in this work and our recent paper that identified alendronate as a promising candidate. In this study, we have investigated all bisphosphonates (BPs) on the ChEMBL database which can bind competitively to nidovirus RdRp-associated nucleotidyl (NiRAN) transferase domain, and systematically down selected seven candidates (CHEMBL608526, CHEMBL196676, CHEMBL164344, CHEMBL4291724, CHEMBL4569308, CHEMBL387132, CHEMBL98211), two of which closely resemble the approved drugs minodronate and zoledronate. This work and our recent paper together provide an in silico mechanistic explanation for alendronate and zoledronate users having dramatically reduced odds of SARS-CoV-2 testing, COVID-19 diagnosis, and COVID-19-related hospitalizations, and indicate that similar observational studies in Japan with minodronate could be valuable.

Kumar V, Sachdeva G, Seshagiri PB. P–258 Ubiquitin, in the human embryo secretome, is a biomarker for embryo viability: a potential predictor of live-births, post embryo transfer

Study question

Whether embryo-secreted ubiquitin could serve as a predictive biomarker for embryo development and viability for assessing pregnancy outcome?

Summary answer

Embryo-secreted ubiquitin concentrations showed positive correlations with (a) developing embryonic stages, (b) implantation rates, (iii) live-birth rates. Their altered levels were associated with miscarriages.

What is known already

Human infertility affects 15–20% couple and is mitigated by ART approaches. Poor biological-viability of in vitro developed embryos contributes to implantation failure and low birth rates(LBR). The current morphology-based embryo selection approach has shortcomings in identifying biologically-viable embryos capable of producing live-births. Earlier studies have identified ubiquitin as a biomarker for embryo developmental competence. However, there have been no studies on estimations of ubiquitin in embryo-spent medium samples (E-SMs) and their correlative analysis with embryo-quality score and pregnancy outcome. Hence, such studies are required to establish whether or not ubiquitin could be a biomarker predicting pregnancy outcome.

Study design, size, duration

This was a retrospective, multi-centric study performed between July 2018 and September 2020. A total of 574 E-SMs (from 574 individual embryos), from 325 infertile women, were analysed for ubiquitin levels. Frozen E-SMs post-thaw were subjected to sandwich ELISA (Mybiosource, USA). Correlation analysis was performed on ubiquitin levels with developing embryonic stages and their scores, implantation rates (IRs) and pregnancy outcomes in terms of LBR.

Participants/materials, setting, methods

We measured ubiquitin levels in E-SMs obtained from three embryonic stages i.e., cleavage-stage (2–10-cells; n = 182), morulae (n = 102) and blastocysts (n = 290). Ubiquitin concentrations among three developmental stages were compared and analysed using the Student’s t-test/ANOVA (P ≤ 0.05), followed by Tukey posthoc test. Levels of ubiquitin were correlated (using Pearson/Spearman analysis) with (a) developing embryonic stages, (b) embryo morphology, (c) IRs, and (d) pregnancy outcomes in terms of LBR.

Main results and the role of chance

Of 574 E-SMs analysed, 540 (94.07%) had detectable ubiquitin levels (pg/ml) and they varied in an increasing manner across developing embryonic stages and, across the three clinics. We observed a significantly different (p < 0.0001) levels of ubiquitin in three sets of secretors i.e low (153.1 ± 5.4; n = 219), medium (498.9 ± 15.7) & high (1615 ± 46.5) secretors. Levels of ubiquitin among three developmental stages were significantly (p < 0.05) different under FET, but not with fresh-ET categories. Ubiquitin levels were independent of cleavage-stage morphology score but showed a positive correlation with blastocyst grades. Also, we observed a significant (p < 0.05) positive correlation of ubiquitin levels with implantation rates. Importantly, ubiquitin levels were higher in E-SMs of embryos which gave live-births vis-à-vis those with no-births. Moreover, altered levels (very high low) were associated with those embryos which resulted in miscarriages. This is the first report which measured ubiquitin in individual hE-SMs from three developing embryos and showed a development stage-wise positive correlations as well as a significant association (p < 0.0001) of ubiquitin levels with implantation and live-birth rates.

Limitations, reasons for caution

Observed variations in levels of ubiquitin across clinics could be attributed to (i) oocyte/sperm donors’ variation and their infertility status (i) IVF-ET protocol differences. A large multi-centric cohort studies are required to establish the predictive value of ubiquitin for assessing embryo-viability and pregnancy outcome in term of live-births.

Wider implications of the findings: For the first time, our multi-centric study showed developmental stage-specific changes in ubiquitin levels. It could be a valuable biomarker of embryo-viability and to predict IR and live-births. Ubiquitin, as a biomarker, could be a valuable adjunct to currently practicing embryo score system for selecting transferable quality embryos.

Trial registration number

Not applicable

Dengue vector surveillance in insular settlements of Pulau Ketam, Selangor, Malaysia

A year-long ovitrap surveillance was conducted between November 2007 and October 2008 in two insular settlements (Kampung Pulau Ketam and Kampung Sungai Lima) within the Malaysian island of Pulau Ketam. Eighty standard ovitraps were placed indoors and outdoors of randomly selected houses/locations. Results demonstrated an endemic baseline Aedes population throughout the year without weekly large fluctuations. Kampung Pulau Ketam has high Aedes aegypti and Aedes albopictus population, but only Ae. aegypti was found in Kampung Sungai Lima. Aedes aegypti showed no preference for ovitraps placed indoor versus outdoor. However, as expected, significantly more outdoor ovitraps were positive for Ae. albopictus (p<0.05). Trends in Ae. albopictus and Ae. aegypti populations mirrored each other suggesting that common factors influenced these two populations.

Molecular and Functional Characterization of Human Sex-Determining Region on the Y Chromosome Variants Using Protamine 1 Promoter

The male sex-determining gene, sex-determining region on the Y chromosome (SRY), is expressed in adult testicular germ cells; however, its role in regulating spermatogenesis remains unclear. The role of SRY in the postmeiotic gene expression was investigated by determining the effect of SRY on the promoter of the haploid-specific Protamine 1 (PRM1) gene, which harbors five distinct SRY-binding motifs. In a luciferase reporter assay system, SRY upregulates PRM1 promoter activity in vitro in a dose-dependent manner. Through a gel-shift assay involving a 31-bp DNA fragment encompassing the SRY element within the PRM1 promoter, the third SRY-binding site on the sense strand (-373/-367) was identified as crucial for PRM1 promoter activation. This assay was extended to analyze 9 SRY variants found in the testicular DNA of 44 azoospermia patients. The findings suggest that SRY regulates PRM1 promoter activity by directly binding to its specific motif within the PRM1 promoter.

P–172 Data-independent acquisition-proteomics of human embryo-spent medium and identification of potential embryo biomarkers

Study question

Can human embryo-derived protein(s) serve as viability biomarkers to predict pregnancy outcome, post embryo transfer?

Summary answer

The human embryo-spent medium proteome, using data-independent acquisition (DIA) approach, could identify novel biomarkers for use in elective embryo transfer.

What is known already

Morphological assessment is used for elective embryo transfer. To improve IVF outcomes and to avoid multiple gestations, embryo-viability assessment is required toward single embryo transfer. Embryo proteomics could provide a non-invasive approach to assess embryo viability. With the advent of DIA mode proteomics, a robust proteome of E-SM could be determined.

Study design, size, duration

This was a retrospective study performed between May and December, 2020 using ten E-SMs obtained from ten individual transferable-quality embryos. Frozen E-SMs, following post-thaw, were subjected to LC-MS-MS analysis. Identified proteome profiles were being potentially correlated to embryo quality scores and pregnancy outcomes in terms of live births.

Participants/materials, setting, methods

The E-SMs were processed for proteomic analysis and subjected to reduction, alkylation and trypsin digestion. Trypsin digested samples were desalted followed by LC-MS/MS using DIA method. Obtained results were searched against human peptide spectral library using Skyline. Differentially expressed proteins were identified by MSStat. Individual peptide peak area under the curve was normalized and analyzed using Student t-test. Fold change was calculated to identify differentially regulated proteins in blank and E-SM samples.

Main results and the role of chance

Using a high-resolution mass spectrometer and high throughput DIA method, we identified 5,502 peptides corresponding to 3,396 proteins from blank and E-SM samples, derived from five non-transferred embryos. We observed that 516 proteins were specific to E-SMs vies-a-vies those of embryo-free blank medium. Statistical analysis showed that 25 proteins were significantly present E-SMs vs. blank. Interestingly, we observed that 16 proteins were down regulated and 9 were up regulated in E-SMs vs. blank medium. Furthermore, E-SMs, from transferred embryos, contained 2,467 peptides corresponding to 1,741 proteins; of these, 1, 689 proteins were specific to E-SMs with 60 (58 down regulated and 2 up regulated) of them being significantly expressed in E-SMs vis-à-vis embryo-free blank medium. Considering the available met analysis published data, our study is the first to use DIA acquisition for high-throughput analysis of human embryo proteome and identification of biomarkers of embryo viability and for possible prediction of pregnancy outcome.

Limitations, reasons for caution

Proteins, other than HAS, detected in the blank medium could be because of non-purified HAS or undeclared proteins and DIA approach used. A large cohort study and meta-analysis using DIA mode are required to establish the embryo-proteome having predictive potential for embryo biological viability.

Wider implications of the findings: For the first time, using DIA mode, a global embryo proteome assessment could be made, establishing a novel embryo viability biomarkers. This, along with the morphological analysis, could be practiced for selection of transferable quality embryo(s)

Trial registration number

Not applicable

Development and evaluation of a one-step SYBR-Green I-based real-time RT-PCR assay for the detection and quantification of Chikungunya virus in human, monkey and mosquito samples

This paper reports the development of a one-step SYBR-Green I-based realtime RT-PCR assay for the detection and quantification of Chikungunya virus (CHIKV) in human, monkey and mosquito samples by targeting the E1 structural gene. A preliminary evaluation of this assay has been successfully completed using 71 samples, consisting of a panel of negative control sera, sera from healthy individuals, sera from patients with acute disease from which CHIKV had been isolated, as well as monkey sera and adult mosquito samples obtained during the chikungunya fever outbreak in Malaysia in 2008. The assay was found to be 100-fold more sensitive than the conventional RT-PCR with a detection limit of 4.12x10(0) RNA copies/μl. The specificity of the assay was tested against other related viruses such as Dengue (serotypes 1-4), Japanese encephalitis, Herpes Simplex, Parainfluenza, Sindbis, Ross River, Yellow fever and West Nile viruses. The sensitivity, specificity and efficiency of this assay were 100%, 100% and 96.8% respectively. This study on early diagnostics is of importance to all endemic countries, especially Malaysia, which has been facing increasingly frequent and bigger outbreaks due to this virus since 1999.

Ovitrap surveillance of the dengue vectors, Aedes (Stegomyia) aegypti (L.) and Aedes (Stegomyia) albopictus Skuse in selected areas in Bentong, Pahang, Malaysia

Ovitrap surveillance was conducted in methodically selected areas in Bentong, Pahang, Malaysia from June 2008 till December 2009 in order to identify insular sites with stable Aedes aegypti population. Eleven sites were surveyed in Bentong district, Pahang, and one of these locations (N3º33' E101º54') was found to have an ovitrap index of Ae. aegypti and Aedes albopictus ranging from 8%-47% and 37%-78% respectively, indicating that this site could be a high-risk area for dengue outbreak. Ae. aegypti larvae were found in both indoor and outdoor ovitraps (p>0.05) while significant difference between the populations of Ae. albopictus larvae from indoors and outdoors was observed (p<0.01). Data collected in this study could provide important entomological information for designing an effective integrated vector control programme to combat Aedes mosquitoes in this area.