Formate is an exciting potential microbial feedstock as it can be derived from CO2 and electricity. Despite this, limited progress has been made in engineering formatotrophy in yeasts, and no yeasts grow using formate naturally. Here we use metabolic modelling to find two potential formatotrophy pathways in Yarrowia lipolytica. We then use C13 tracer analysis and computationally guided growth experiments to show that wild-type Y. lipolytica possesses strong formate dissimilation and a cyclical C1 pathway with similar architecture to the synthetic serine-threonine cycle, which it uses to co-assimilate formate and glycerol. Messenger RNA sequencing shows that formate exposure results in increased oxidative stress and changes in the tricarboxylic acid cycle, redox and C1 metabolism. Following this, we use model-guided adaptive laboratory evolution to produce a formatotrophic strain of Y. lipolytica using the eukaryotic serine-threonine cycle. We then use further messenger RNA sequencing to show that formatotrophy is supported by changes in adenosine triphosphate and reactive oxygen species metabolism. Subsequently, we engineer nicotinamide adenine dinucleotide phosphate (NADPH) and reactive oxygen species metabolism to create a strain with substantially improved growth. This strain reaches about 10% of the theoretical maximum biomass yield, highlighting its potential for additional engineering approaches. Finally, we show that beta-carotene production from formate is possible in our engineered strain, opening the door to formatotrophic eukaryote bioprocesses.
Schistosomiasis remains a major public health concern in Nigeria. We molecularly characterized Schistosoma eggs obtained from human urine to identify species and assess the presence of hybrid schistosomes in Abuja, Nigeria. Urine samples were collected from 1,887 participants aged five years and above. Samples were examined for Schistosoma eggs using light microscopy. A total of 507 (26.9%) were positive for any form of Schistosoma while 91 (4.8%) had atypical Schistosoma eggs. DNA extracted from pooled ova was analyzed using metagenomic sequencing, read mapping, phylogenetic analysis, and BLASTn confirmation. Molecular analyses identified genetic signatures associated with both S. haematobium and S. bovis within pooled human urine samples, indicating the co-circulation of multiple schistosome species in the study area. Phylogenetic analyses based on trans-ITS and mitochondrial COX1 markers supported the presence of distinct nuclear and mitochondrial schistosome lineages. However, because sequencing was performed on pooled egg samples, the findings cannot distinguish between true recombinants and mixed infections involving co-circulating parental species. These findings highlight the potential complexity of schistosome transmission dynamics in endemic communities and underscore the need for enhanced molecular surveillance especially single-parasite genomic approaches, and integrated One Health investigations to better understand schistosome transmission and its implications for control and elimination efforts in Nigeria.
Schistosomiasis is a public health concern and there is a need for reliable field-compatible diagnostic methods in endemic settings. The AiDx Assist, an artificial intelligence (AI)-based automated microscope, has shown promising results for the detection of Schistosoma haematobium eggs in urine. It has been further developed to detect Schistosoma mansoni eggs in stool. In this study, we evaluated the performance of the AiDx Assist for the detection of S. mansoni eggs in stool samples and further validated the performance of the AiDx Assist for the detection of S. haematobium eggs in urine samples. Additionally, the potential of the AiDx Assist for the detection of other helminths in stool samples was explored. In total, 405 participants from an area endemic for both S. mansoni and S. haematobium provided stool and urine samples which were subjected to AiDx Assist (semi- and fully automated), while conventional microscopy was used as the diagnostic reference. Only samples with complete test results were included in the final analysis, resulting in 375 stool and 398 urine samples, of which 38.4% and 65.3% showed Schistosoma eggs by conventional microscopy. The collected images of the stool samples were retrospectively examined for other helminth eggs via manual analysis. For the detection of S. mansoni eggs, the sensitivity of the semi-automated AiDx Assist (86.8%) was significantly higher compared to the fully automated AiDx Assist (56.9%) while the specificity was comparable, with 81.4% and 86.8%, respectively. Retrospectively, eggs of Ascaris lumbricoides and Trichuris trichiura were visualized. For the examination of urine samples, a comparable sensitivity in the detection of S. haematobium eggs was found between the semi-and the fully automated modes of the AiDx Assist, showing 94.6% and 91.9%, respectively. Furthermore, the specificity was comparable, with 90.6%and 91.3% respectively. The AiDx Assist met the World Health Organization Target Product Profile criteria in terms of diagnostic accuracy for the detection of S. haematobium eggs in urine samples and performed modestly in the detection of S. mansoni eggs in stool samples. With some further improvements, it has the potential to become a valuable diagnostic tool for screening multiple helminth parasites in stool and urine samples.
Background: Schistosomiasis (SCH) and soil transmitted helminthiasis (STH) have been targeted for elimination as a public health problem (EPHP) within the World Health Organization (WHO)’s Roadmap for Neglected Tropical Diseases (NTDs) 2021–2030. One of the global strategies for the control and elimination of these diseases is the mass administration of praziquantel and albendazole/mebendazole without prior individual diagnosis. To measure the progress towards the 2030 target, we conducted an assessment to determine the impact of the 3–5 rounds of annual mass drug administration among school age children in Ekiti State. Such scientific insights into the impact of these treatments will facilitate improved planning and targeting of resources towards reaching the last mile. Methodology: This assessment was conducted in 16 local government areas (LGAs) of Ekiti State between October and November 2023. Samples were collected from pupils in 166 primary and junior secondary schools across 166 wards of the State. Urine and stool samples were collected from 7670 pupils of ages 5 to 14 years, following standard laboratory procedures. Urine membrane filtration techniques were used for urine preparation while the Kato–Katz technique was used for stool preparation. A novel AiDx digital microscope was used to examine the presence of any ova in the prepared specimen. Parasite ova in urine were reported as the number of ova/10 mL of urine, and were categorized as light infection (˂50 ova/10 mL of urine) or heavy infection (>50 ova/10 mL of urine) while ova of parasites in stool samples were reported as eggs per gram of stool (EPG) and categorized into light, moderate and heavy infection. Results: Overall, 0.76% (0.56–0.95) at 95% CI of the 7670 respondents were infected with Schistosomia haematobium. No Schistosoma mansoni infection was recorded in the study. Similarly, 3.9% (3.43–4.29) at 95% CI were infected with STHs. The overall prevalence of schistosomiasis had significantly reduced from 8.2% in 2008 to 0.8%, while the overall prevalence of STHs significantly reduced from 30.9% to 3.9% with Ascaris lumbricoides being the dominant species of STH. In the 16 LGAs assessed, Ekiti West had the highest S. haematobium prevalence of 4.26%. Ise/Orun and Oye ranked second and third with a prevalence of 3.48% and 2.40% respectively, while all other LGAs had <1% prevalence. The prevalence of STHs was highest in Ekiti-West with a prevalence of 10.45% while Emure and Ikole Local Governments had the lowest prevalence of 0.31% and 0.38%, respectively. There was no significant difference in the prevalence of schistosomiasis between male (0.76%) and female (0.75%) as p ≥ 0.05. Similarly, the difference in prevalence for STH among males (3.95%) was not significantly different from their female counterparts (3.77%), p ≥ 0.05. Conclusions: Based on the WHO guidelines, this study demonstrated that only three LGAs require continued MDA every 2/3 years, seven require only surveillance while six are now non-endemic for schistosomiasis. Similarly, two of the LGAs require one round of MDA yearly, eight LGAs need one round of MDA every two to three years and six LGAs are now below the treatment threshold and no longer require treatment for STH.
β-Caryophyllene, a sesquiterpenoid, holds considerable potential in pharmaceutical, nutraceutical, cosmetic, and chemical industries. In order to overcome the limitation of β-caryophyllene production by the extraction from plants or chemical synthesis, we aimed the microbial production of β-caryophyllene in non-conventional yeast Yarrowia lipolytica in this study. Two genes, tHMG1 from S. cerevisiae to boost the mevalonate pool and QHS1 from Artemisia annua, were expressed under different promoters and copy numbers in Y. lipolytica. The co-expression of 8UAS pEYK1-QHS1 and pTEF-tHMG1 in the obese strain yielded 165.4 mg/L and 201.5 mg/L of β-caryophyllene in single and double copies, respectively. Employing the same combination of promoters and genes in wild-type-based strain with two copies resulted in a 1.36-fold increase in β-caryophyllene. The introduction of an additional three copies of 8UAS pEYK1-tHMG1 further augmented the β-caryophyllene, reaching 318.5 mg/L in flask fermentation. To maximize the production titer, we optimized the carbon source ratio between glucose and erythritol as well as fermentation condition that led to 798.1 mg/L of β-caryophyllene. A biosynthetic pathway of β-caryophyllene was firstly investigated in Y. lipolytica in this study. Through the modulation of key enzyme expression, we successfully demonstrated an improvement in β-caryophyllene production. This strategy suggests its potential extension to studies involving the microbial production of various industrially relevant terpenes.
Methanol is a promising sustainable alternative feedstock for green biomanufacturing. The yeast Yarrowia lipolytica offers a versatile platform for producing a wide range of products but it cannot use methanol efficiently. In this study, we engineered Y. lipolytica to utilize methanol by overexpressing a methanol dehydrogenase, followed by the incorporation of methanol assimilation pathways from methylotrophic yeasts and bacteria. We also overexpressed the ribulose monophosphate (RuMP) and xylulose monophosphate (XuMP) pathways, which led to significant improvements in growth with methanol, reaching a consumption rate of 2.35 g/L in 24 h and a 2.68-fold increase in biomass formation. Metabolomics and Metabolite Flux Analysis confirmed methanol assimilation and revealed an increase in reducing power. The strains were further engineered to produce the valuable heterologous product resveratrol from methanol as a co-substrate. Unlike traditional methanol utilization processes, which are often resource-intensive and environmentally damaging, our findings represent a significant advance in green chemistry by demonstrating the potential of Y. lipolytica for efficient use of methanol as a co-substrate for energy, biomass, and product formation. This work not only contributes to our understanding of methanol metabolism in non-methylotrophic organisms but also paves the way for achieving efficient synthetic methylotrophy towards green biomanufacturing.
Community mobilisation is a vital process for raising awareness and increasing participation in healthcare interventions, research, and programmes that require human sample collection and mass management. In this report, we present the community mobilisation approach undertaken for the implementation of the operational mapping and assessment of granular schistosomiasis and soil-transmitted helminths in Ekiti State, Nigeria. The mobilisation was conducted in 177 communities/wards of the 16 local government areas. A total of 15,340 urine and stool samples were collected in 34 days. The efficacy and success of the strategy were evaluated through the following three performance metrics: community compliance rate, the participant response rate at the community level, and the overall compliance response rate of the four most sensitive LGAs. Community compliance was 93.7% as sample collection was denied in nine communities and two other communities demanded the return of the collected samples despite our mobilisation effort because of cultural bias and myths that connect the collection of stool and urine samples to ritual activities in the local context. The participant response rate at the community level was 86.7%. Three of the four sensitive LGAs (based on previous assessment programmes) demonstrated satisfactory compliance rates of 100%, while a response rate of 64.0% was computed for one of the LGAs. We believe our approach contributed to effective community mobilisation and awareness and that the developed model has the potential to improve participation rates in large healthcare assessments and intervention programmes.
Applying low-cost substrate is critical for sustainable bioproduction. Co-culture of phototrophic and heterotrophic microorganisms can be a promising solution as they can use CO2 and light as feedstock. This study aimed to create a light-driven consortium using a marine cyanobacterium Synechococcus sp. PCC 7002 and an industrial yeast Yarrowia lipolytica. First, the cyanobacterium was engineered to accumulate and secrete sucrose by regulating the expression of genes involved in sucrose biosynthesis and transport, resulting in 4.0 g/L of sucrose secretion. Then, Yarrowia lipolytica was engineered to efficiently use sucrose and produce β-caryophyllene that has various industrial applications. Then, co- and sequential-culture were optimized with different induction conditions and media compositions. A maximum β-caryophyllene yield of 14.1 mg/L was obtained from the co-culture. This study successfully established an artificial light-driven consortium based on a marine cyanobacterium and Y. lipolytica, and provides a foundation for sustainable bioproduction from CO2 and light through co-culture systems.
Background Limonene has a variety of applications in the foods, cosmetics, pharmaceuticals, biomaterials, and biofuels industries. In order to meet the growing demand for sustainable production of limonene at industry scale, it is essential to find an alternative production system to traditional plant extraction. A promising and eco-friendly alternative is the use of microbes as cell factories for the synthesis of limonene. Results In this study, the oleaginous yeast Yarrowia lipolytica has been engineered to produce d- and l-limonene. Four target genes, l- or d-LS (limonene synthase), HMG (HMG-CoA reductase), ERG20 (geranyl diphosphate synthase), and NDPS1 (neryl diphosphate) were expressed individually or fused together to find the optimal combination for higher limonene production. The strain expressing HMGR and the fusion protein ERG20-LS was the best limonene producer and, therefore, selected for further improvement. By increasing the expression of target genes and optimizing initial OD, 29.4 mg/L of l-limonene and 24.8 mg/L of d-limonene were obtained. We also studied whether peroxisomal compartmentalization of the synthesis pathway was beneficial for limonene production. The introduction of d-LS and ERG20 within the peroxisome improved limonene titers over cytosolic expression. Then, the entire MVA pathway was targeted to the peroxisome to improve precursor supply, which increased d-limonene production to 47.8 mg/L. Finally, through the optimization of fermentation conditions, d-limonene production titer reached 69.3 mg/L. Conclusions In this work, Y. lipolytica was successfully engineered to produce limonene. Our results showed that higher production of limonene was achieved when the synthesis pathway was targeted to the peroxisome, which indicates that this organelle can favor the bioproduction of terpenes in yeasts. This study opens new avenues for the efficient synthesis of valuable monoterpenes in Y. lipolytica.
Since joining SynbiCITE, the national centre for translating synthetic biology, a decade ago as the lone analytical chemist, the centre has gone from limited lab space to playing its part in securing funding, growth and development of more than 50 companies focused on engineering biology. Synthetic biology has proved to be viable technology, with the number of sustainable companies continuing to grow in this field. This communication provides a personal perspective of 10 years in translational engineering of biology, as seen from the experimental analytics position and working with the companies contributing to the growth of the UK bioeconomy.
In this research, we report on the performance of automated optical digital detection and quantification of Schistosoma haematobium provided by AiDx NTDx multi-diagnostic Assist microscope. Our study was community-based, and a convenient sampling method was used in 17 communities in Abuja Nigeria, based on the disease prevalence information extracted from the baseline database on schistosomiasis, NTD Division, of the Federal Ministry of Health. At baseline, samples from 869 participants were evaluated of which 358 (34.1%) tested S. haematobium positive by the reference diagnostic standard. Registered images from the fully automated (autofocusing, scanning, image registration and processing, AI image analysis and automatic parasite count) AiDx assist microscope were analyzed. The Semi automated (autofocusing, scanning, image registration & processing and manual parasite count) and the fully automated AiDx Assist showed comparable sensitivities and specificities of [90.3%, 98%] and [89%, 99%] respectively. Overall, estimated egg counts of the semi-automated & fully automated AiDx Assist correlated significantly with the egg counts of conventional microscopy ( r = 0.93 , p ≤ 0.001 and r = 0.89, p ≤ 0.001 respectively). The AiDx Assist device performance is consistent with requirement of the World Health Organization diagnostic target product profile for monitoring, evaluation, and surveillance of Schistosomiasis elimination Programs.
The World Health Organization's broad definition of health embraces physical, mental and social well-being. Expressed in its 1946 constitution alongside concepts of community participation and national sovereignty, it reflected an understanding of a world emerging from centuries of colonialist oppression and the public health industry's shameful facilitation of fascism. Health policy would be people-centered, closely tied to human rights and self-determination. The COVID-19 response has demonstrated how these ideals have been undone. Decades of increasing funding within public-private partnerships have corroded the basis of global public health. The COVID-19 response, intended for a virus that overwhelmingly targeted the elderly, ignored norms of epidemic management and human rights to institute a regime of suppression, censorship, and coercion reminiscent of the power systems and governance that were previously condemned. Without pausing to examine the costs, the public health industry is developing international instruments and processes that will entrench these destructive practices in international law. Public health, presented as a series of health emergencies, is being used once again to facilitate a fascist approach to societal management. The beneficiaries will be the corporations and investors whom the COVID-19 response served well. Human rights and individual freedom, as under previous fascist regimes, will lose. The public health industry must urgently awaken to the changing world in which it works, if it is to adopt a role in saving public health rather than contributing to its degradation.
Microbial-derived aromatics provide a sustainable and renewable alternative to petroleum-derived chemicals. In this study, we used the model yeast Saccharomyces cerevisiae to produce aromatic molecules by exploiting the concept of modularity in synthetic biology. Three different modular approaches were investigated for the production of the valuable fragrance raspberry ketone (RK), found in raspberry fruits and mostly produced from petrochemicals. The first strategy used was modular cloning, which enabled the generation of combinatorial libraries of promoters to optimize the expression level of the genes involved in the synthesis pathway of RK. The second strategy was modular pathway engineering and involved the creation of four modules, one for product formation: RK synthesis module (Mod. RK); and three for precursor synthesis: aromatic amino acid synthesis module (Mod. Aro), p-coumaric acid synthesis module (Mod. p-CA), and malonyl-CoA synthesis module (Mod. M-CoA). The production of RK by combinations of the expression of these modules was studied, and the best engineered strain produced 63.5 mg/L RK from glucose, which is the highest production described in yeast, and 2.1 mg RK/g glucose, which is the highest yield reported in any organism without p-coumaric acid supplementation. The third strategy was the use of modular cocultures to explore the effects of division of labor on RK production. Two two-member communities and one three-member community were created, and their production capacity was highly dependent on the structure of the synthetic community, the inoculation ratio, and the culture media. In certain conditions, the cocultures outperformed their monoculture controls for RK production, although this was not the norm. Interestingly, the cocultures showed up to 7.5-fold increase and 308.4 mg/L of 4-hydroxy benzalacetone, the direct precursor of RK, which can be used for the semi-synthesis of RK. This study illustrates the utility of modularity in synthetic biology tools and their applications to the synthesis of products of industrial interest.
Community awareness and participation in mass screening is critical for schistosomiasis control. This study assessed the impact of sharing anonymized image-based positive test results on the uptake of screening during community mobilization outreach. We conducted an observational study to compare the population response to standard and image-based strategies in 14 communities in Abuja, Nigeria. Six hundred and ninety-one (341 females, 350 males) individuals participated in this study. We analyzed the response ratio, relative increase, and sample collection time. The potential treatment uptake and change in social behavior were determined based on a semi-structured questionnaire. The mean response ratio of the image-based strategy was 89.7% representing a significantly higher ratio than the 27.8%, which was observed under the standard mobilization approach (p ≤ 0.001). The image-based method was associated with 100% of the participants agreeing to provide urine samples, 94% willing to be treated, 89% claiming to have been invited to participate in the study by a friend, and 91% desiring to change a predisposing behavioral habit. These findings indicate that image-based community awareness campaigns may increase the population’s perception about schistosomiasis transmission and treatment. This raises new possibilities for local resource mobilization to expand services in reaching the last mile in schistosomiasis control.
COVAX, the international initiative supporting COVID-19 vaccination campaigns globally, is budgeted to be the costliest public health initiative in low- and middle-income countries, with over 16 billion US dollars already committed. While some claim that the target of vaccinating 70% of people worldwide is justified on equity grounds, we argue that this rationale is wrong for two reasons. First, mass COVID-19 vaccination campaigns do not meet standard public health requirements for clear expected benefit, based on costs, disease burden and intervention effectiveness. Second, it constitutes a diversion of resources from more cost-effective and impactful public health programmes, thus reducing health equity. We conclude that the COVAX initiative warrants urgent review.
The ergot alkaloids are a class of natural products known for their pharmacologically privileged molecular structure that are used in the treatment of neurological ailments, such as Parkinsonism and dementia. Their synthesis via chemical and biological routes are therefore of industrial relevance, but suffer from several challenges. Current chemical synthesis methods involve long, multi-step reactions with harsh conditions and are not enantioselective; biological methods utilizing ergot fungi, produce an assortment of products that complicate product recovery, and are susceptible to strain degradation. Reconstituting the ergot alkaloid pathway in a strain strongly amenable for liquid fermentation, could potentially resolve these issues. In this work, we report the production of the main ergoline therapeutic precursor, D -lysergic acid, to a titre of 1.7 mg L −1 in a 1 L bioreactor. Our work demonstrates the proof-of-concept for the biological production of ergoline-derived compounds from sugar in an engineered yeast chassis.