Long-term trends (1986-2019) in the physicochemical properties of the Sado Estuary (Portugal) driven primarily by changes in river flow and influenced by marine upwelling.

Estuaries are among the most sensitive systems to climate change. Previous studies have suggested that the Sado Estuary (Portugal) has decreasing trends for water temperature, which is uncommon in a global warming scenario. However, no long-term analysis regarding water column conditions has been conducted on this estuary to date. Therefore, the main aim of this study is to understand if and how the properties of this estuary have changed, considering a 34-year trend analysis and an assessment of their main drivers. Water temperature significantly decreased (up to 0.04 °C/year) along with chlorophyll a. Salinity increased and nutrients displayed an overall decrease. These trends were potentially driven by higher influence of upwelled water combined with a reduction of the river flow. Sado appears to have a lower vulnerability to climate change than other estuaries as it does not show a high sensitivity to changes in its water column physicochemical properties.

Structural Insights into Ciona intestinalis Septins: Complexes Suggest a Mechanism for Nucleotide-dependent Interfacial Cross-talk.

Septins are filamentous nucleotide-binding proteins which can associate with membranes in a curvature-dependent manner leading to structural remodelling and barrier formation. Ciona intestinalis, a model for exploring the development and evolution of the chordate lineage, has only four septin-coding genes within its genome. These represent orthologues of the four classical mammalian subgroups, making it a minimalist non-redundant model for studying the modular assembly of septins into linear oligomers and thereby filamentous polymers. Here, we show that C. intestinalis septins present a similar biochemistry to their human orthologues and also provide the cryo-EM structures of an octamer, a hexamer and a tetrameric sub-complex. The octamer, which has the canonical arrangement (2-6-7-9-9-7-6-2) clearly shows an exposed NC-interface at its termini enabling copolymerization with hexamers into mixed filaments. Indeed, only combinations of septins which had CiSEPT2 occupying the terminal position were able to assemble into filaments via NC-interface association. The CiSEPT7-CiSEPT9 tetramer is the smallest septin particle to be solved by Cryo-EM to date and its good resolution (2.7 Å) provides a well-defined view of the central NC-interface. On the other hand, the CiSEPT7-CiSEPT9 G-interface shows signs of fragility permitting toggling between hexamers and octamers, similar to that seen in human septins but not in yeast. The new structures provide insights concerning the molecular mechanism for cross-talk between adjacent interfaces. This indicates that C. intestinalis may represent a valuable tool for future studies, fulfilling the requirements of a complete but simpler system to understand the mechanisms behind the assembly and dynamics of septin filaments.

Structural and thermodynamic characterization of a highly amyloidogenic dimer of transthyretin involved in a severe cardiomyopathy.

Transthyretin (TTR) is an homotetrameric protein involved in the transport of thyroxine. More than 150 different mutations have been described in the TTR gene, several of them associated with familial amyloid cardiomyopathy. Recently, our group described a new variant of TTR in Brazil, namely A39D-TTR, which causes a severe cardiac condition. Position 39 is in the AB loop, a region of the protein that is located within the thyroxine-binding channels and is involved in tetramer formation. In the present study, we solved the structure and characterize the thermodynamic stability of this new variant of TTR using urea and high hydrostatic pressure. Interestingly, during the process of purification, A39D-TTR turned out to be a dimer and not a tetramer, a variation that might be explained by the close contact of the four aspartic acids at position 39, where they face each other inside the thyroxine channel. In the presence of subdenaturing concentrations of urea, bis-ANS binding and dynamic light scattering revealed A39D-TTR in the form of a molten-globule dimer. Co-expression of A39D and WT isoforms in the same bacterial cell did not produce heterodimers or heterotetramers, suggesting that somehow a negative charge at the AB loop precludes tetramer formation. A39D-TTR proved to be highly amyloidogenic, even at mildly acidic pH values where WT-TTR does not aggregate. Interestingly, despite being a dimer, aggregation of A39D-TTR was inhibited by diclofenac, which binds to the thyroxine channel in the tetramer, suggesting the existence of other pockets in A39D-TTR able to accommodate this molecule.

Bacterial selenocysteine synthase structure revealed by single-particle cryoEM.

The 21st amino acid, selenocysteine (Sec), is synthesized on its dedicated transfer RNA (tRNASec). In bacteria, Sec is synthesized from Ser-tRNA[Ser]Sec by Selenocysteine Synthase (SelA), which is a pivotal enzyme in the biosynthesis of Sec. The structural characterization of bacterial SelA is of paramount importance to decipher its catalytic mechanism and its role in the regulation of the Sec-synthesis pathway. Here, we present a comprehensive single-particle cryo-electron microscopy (SPA cryoEM) structure of the bacterial SelA with an overall resolution of 2.69 Å. Using recombinant Escherichia coli SelA, we purified and prepared samples for single-particle cryoEM. The structural insights from SelA, combined with previous in vivo and in vitro knowledge, underscore the indispensable role of decamerization in SelA's function. Moreover, our structural analysis corroborates previous results that show that SelA adopts a pentamer of dimers configuration, and the active site architecture, substrate binding pocket, and key K295 catalytic residue are identified and described in detail. The differences in protein architecture and substrate coordination between the bacterial enzyme and its counterparts offer compelling structural evidence supporting the independent molecular evolution of the bacterial and archaea/eukarya Ser-Sec biosynthesis present in the natural world.

Structural insights into the Smirnoff-Wheeler pathway for vitamin C production in the Amazon fruit camu-camu.

l-Ascorbic acid (AsA, vitamin C) is a pivotal dietary nutrient with multifaceted importance in living organisms. In plants, the Smirnoff-Wheeler pathway is the primary route for AsA biosynthesis, and understanding the mechanistic details behind its component enzymes has implications for plant biology, nutritional science, and biotechnology. As part of an initiative to determine the structures of all six core enzymes of the pathway, the present study focuses on three of them in the model species Myrciaria dubia (camu-camu): GDP-d-mannose 3',5'-epimerase (GME), l-galactose dehydrogenase (l-GalDH), and l-galactono-1,4-lactone dehydrogenase (l-GalLDH). We provide insights into substrate and cofactor binding and the conformational changes they induce. The MdGME structure reveals a distorted substrate in the active site, pertinent to the catalytic mechanism. Mdl-GalDH shows that the way in which NAD+ association affects loop structure over the active site is not conserved when compared with its homologue in spinach. Finally, the structure of Mdl-GalLDH is described for the first time. This allows for the rationalization of previously identified residues which play important roles in the active site or in the formation of the covalent bond with FAD. In conclusion, this study enhances our understanding of AsA biosynthesis in plants, and the information provided should prove useful for biotechnological applications.

Viés Atencional na Esquizofrenia: uma Revisão Crítica da Literatura / Attentional Bias in Schizophrenia: a Critical Review of Literature

O viés atencional, compreendido como a tendência de processar informações de acordo com a valência emocional ou significado, pode contribuir para a vulnerabilidade a transtornos psiquiátricos. Este estudo apresenta uma revisão da literatura sobre pesquisas empíricas que investigaram associações entre viés atencional e esquizofrenia. A busca foi realizada nas bases de dados PsycInfo, Web of Science, MedLine e Scopus. Um total de 641 estudos foi identificado. Após a aplicação dos critérios de elegibilidade, 16 artigos foram incluídos na amostra final, com a inclusão de um artigo a partir das referências dos estudos da amostra. Foram observados a utilização de tarefas e estímulos diversos, que apresentaram resultados variados, indicando, por um lado, a presença de viés atencional, e, por outro, interferência equivalente de estímulos emocionais em pacientes e pessoas saudáveis. São necessários mais estudos que, além de investigarem a associação entre viés atencional e esquizofrenia, permitam o controle de variáveis confundidoras.

Attentional bias, understood as the tendency to process information according to emotional valence or meaning, can contribute to vulnerability to psychiatric disorders. This study presents a review of empirical research literature that investigated the associations between attentional bias and schizophrenia. The search was conducted in the PsycInfo, Web of Science, MedLine, and Scopus databases. A total of 641 studies were identified. After applying eligibility criteria, 16 articles were included in the final sample, including one article retrieved from the references of the sample studies. Various tasks and stimuli were observed, yielding diverse results, indicating, on the one hand, the presence of attentional bias, and on the other hand, equivalent interference from emotional stimuli in patients and healthy individuals. Further studies are needed that, in addition to investigating the association between attentional bias and schizophrenia, allow for the control of confounding variables.

X-ray structure of the metastable SEPT14-SEPT7 coiled coil reveals a hendecad region crucial for heterodimerization.

Septins are membrane-associated, GTP-binding proteins that are present in most eukaryotes. They polymerize to play important roles as scaffolds and/or diffusion barriers as part of the cytoskeleton. α-Helical coiled-coil domains are believed to contribute to septin assembly, and those observed in both human SEPT6 and SEPT8 form antiparallel homodimers. These are not compatible with their parallel heterodimeric organization expected from the current model for protofilament assembly, but they could explain the interfilament cross-bridges observed by microscopy. Here, the first structure of a heterodimeric septin coiled coil is presented, that between SEPT14 and SEPT7; the former is a SEPT6/SEPT8 homolog. This new structure is parallel, with two long helices that are axially shifted by a full helical turn with reference to their sequence alignment. The structure also has unusual knobs-into-holes packing of side chains. Both standard seven-residue (heptad) and the less common 11-residue (hendecad) repeats are present, creating two distinct regions with opposite supercoiling, which gives rise to an overall straight coiled coil. Part of the hendecad region is required for heterodimerization and therefore may be crucial for selective septin recognition. These unconventional sequences and structural features produce a metastable heterocomplex that nonetheless has enough specificity to promote correct protofilament assembly. For instance, the lack of supercoiling may facilitate unzipping and transitioning to the antiparallel homodimeric state.

Bacteria and Yeast Colony PCR.

The bacteria Escherichia coli and the yeast Saccharomyces cerevisiae are currently the two most important organisms in synthetic biology. E. coli is almost always used for fundamental DNA manipulation, while yeast is the simplest host system for studying eukaryotic gene expression and performing large-scale DNA assembly. Yeast expression studies may also require altering the chromosomal DNA by homologous recombination. All these studies require the verification of the expected DNA sequence, and the fastest method of screening is colony PCR, which is direct PCR of DNA in cells without prior DNA purification. Colony PCR is hampered by the difficulty of releasing DNA into the PCR mix and by the presence of PCR inhibitors. We hereby present one protocol for E. coli and two protocols for S. cerevisiae differing in efficiency and complexity as well as an overview of past and possible future developments of efficient S. cerevisiae colony PCR protocols.

Engineering the catalytic activity of an Antarctic PET-degrading enzyme by loop exchange.

Several hydrolases have been described to degrade polyethylene terephthalate (PET) at moderate temperatures ranging from 25°C to 40°C. These mesophilic PET hydrolases (PETases) are less efficient in degrading this plastic polymer than their thermophilic homologs and have, therefore, been the subject of many protein engineering campaigns. However, enhancing their enzymatic activity through rational design or directed evolution poses a formidable challenge due to the need for exploring a large number of mutations. Additionally, evaluating the improvements in both activity and stability requires screening numerous variants, either individually or using high-throughput screening methods. Here, we utilize instead the design of chimeras as a protein engineering strategy to increase the activity and stability of Mors1, an Antarctic PETase active at 25°C. First, we obtained the crystal structure of Mors1 at 1.6 Å resolution, which we used as a scaffold for structure- and sequence-based chimeric design. Then, we designed a Mors1 chimera via loop exchange of a highly divergent active site loop from the thermophilic leaf-branch compost cutinase (LCC) into the equivalent region in Mors1. After restitution of an active site disulfide bond into this chimera, the enzyme exhibited a shift in optimal temperature for activity to 45°C and an increase in fivefold in PET hydrolysis when compared with wild-type Mors1 at 25°C. Our results serve as a proof of concept of the utility of chimeric design to further improve the activity and stability of PETases active at moderate temperatures.

A key piece of the puzzle: The central tetramer of the Saccharomyces cerevisiae septin protofilament and its implications for self-assembly.

Septins, often described as the fourth component of the cytoskeleton, are structural proteins found in a vast variety of living beings. They are related to small GTPases and thus, generally, present GTPase activity which may play an important (although incompletely understood) role in their organization and function. Septins polymerize into long non-polar filaments, in which each subunit interacts with two others by alternating interfaces, NC and G. In Saccharomyces cerevisiae four septins are organized in the following manner, [Cdc11-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11]n in order to form filaments. Although septins were originally discovered in yeast and much is known regarding their biochemistry and function, only limited structural information about them is currently available. Here we present crystal structures of Cdc3/Cdc10 which provide the first view of the physiological interfaces formed by yeast septins. The G-interface has properties which place it in between that formed by SEPT2/SEPT6 and SEPT7/SEPT3 in human filaments. Switch I from Cdc10 contributes significantly to the interface, whereas in Cdc3 it is largely disorded. However, the significant negative charge density of the latter suggests it may have a unique role. At the NC-interface, we describe an elegant means by which the sidechain of a glutamine from helix α0 imitates a peptide group in order to retain hydrogen-bond continuity at the kink between helices α5 and α6 in the neighbouring subunit, thereby justifying the conservation of the helical distortion. Its absence from Cdc11, along with this structure's other unusual features are critically discussed by comparison with Cdc3 and Cdc10.

Effects of climate change on aquaculture site selection at a temperate estuarine system.

Aquaculture is one of the food industries that most evolved in recent years in response to increased human demand for seafood products, which has led to a progressive stock threat in nature. With a high seafood consumption per capita, Portugal has been exploring its coastal systems to improve the cultivation of fish and bivalve species with high commercial value. In this context, this study aims to propose the use of a numerical model as a tool to assess the impact of climate change on aquaculture site selection in a temperate estuarine system (Sado estuary). Therefore, the Delft3D model was calibrated and validated, showing good accuracy in predicting the local hydrodynamics, transport, and water quality. Furthermore, two simulations for the historical and future conditions were performed to establish a Suitability Index capable of identifying the most appropriate sites to exploit two bivalve species (one clam and one oyster), considering both winter and summer seasons. Results suggest that the estuary's northernmost region presents the best conditions for bivalves' exploitation, with more suitable conditions during summer than winter due to the higher water temperature and chlorophyll-a concentrations. Regarding future projections, the model results suggest that environmental conditions will likely benefit the production of both species due to the increase in chlorophyll-a concentration along the estuary.

HGPRT and PNP: Recombinant Enzymes from Schistosoma mansoni and Their Role in Immunotherapy during Experimental Murine Schistosomiasis.

Schistosomiasis is a parasitic infection caused by trematode worms (also called blood flukes) of the genus Schistosoma sp., which affects over 230 million people worldwide, causing 200,000 deaths annually. There is no vaccine or new drugs available, which represents a worrying aspect, since there is loss of sensitivity of the parasite to the medication recommended by the World Health Organization, Praziquantel. The present study evaluated the effects of the recombinant enzymes of S. mansoni Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT), Purine Nucleoside Phosphorylase (PNP) and the MIX of both enzymes in the immunotherapy of schistosomiasis in murine model. These enzymes are part of the purine salvage pathway, the only metabolic pathway present in the parasite for this purpose, being essential for the synthesis of DNA and RNA. Female mice of Swiss and BALB/c strains were infected with cercariae and treated, intraperitoneally, with three doses of 100 µg of enzymes. After the immunotherapy, the eggs and adult worms were counted in the feces; the number of eosinophils from the fluid in the peritoneal cavity and peripheral blood was observed; and the quantification of the cytokine IL-4 and the production of antibodies IgE was analyzed. The evaluation of the number of granulomas and collagen deposition via histological slides of the liver was performed. The results demonstrate that immunotherapy with the enzyme HGPRT seems to stimulate the production of IL-4 and promoted a significant reduction of granulomas in the liver in treated animals. The treatment with the enzyme PNP and the MIX was able to reduce the number of worms in the liver and in the mesenteric vessels of the intestine, to reduce the number of eggs in the feces and to negatively modulate the number of eosinophils. Therefore, immunotherapy with the recombinant enzymes of S. mansoni HGPRT and PNP might contribute to the control and reduction of the pathophysiological aspects of schistosomiasis, helping to decrease the morbidity associated with the infection in murine model.

Allosteric regulation and crystallographic fragment screening of SARS-CoV-2 NSP15 endoribonuclease.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). The NSP15 endoribonuclease enzyme, known as NendoU, is highly conserved and plays a critical role in the ability of the virus to evade the immune system. NendoU is a promising target for the development of new antiviral drugs. However, the complexity of the enzyme's structure and kinetics, along with the broad range of recognition sequences and lack of structural complexes, hampers the development of inhibitors. Here, we performed enzymatic characterization of NendoU in its monomeric and hexameric form, showing that hexamers are allosteric enzymes with a positive cooperative index, and with no influence of manganese on enzymatic activity. Through combining cryo-electron microscopy at different pHs, X-ray crystallography and biochemical and structural analysis, we showed that NendoU can shift between open and closed forms, which probably correspond to active and inactive states, respectively. We also explored the possibility of NendoU assembling into larger supramolecular structures and proposed a mechanism for allosteric regulation. In addition, we conducted a large fragment screening campaign against NendoU and identified several new allosteric sites that could be targeted for the development of new inhibitors. Overall, our findings provide insights into the complex structure and function of NendoU and offer new opportunities for the development of inhibitors.

Effects of Immunization with Recombinant Schistosoma mansoni Enzymes AK and HGPRT: Murine Infection Control.

Schistosomiasis is one of the most important human helminthiases worldwide. Praziquantel is the current treatment, and no vaccine is available until the present. Thus, the presented study aimed to evaluate the immunization effects with recombinant Schistosoma mansoni enzymes: Adenosine Kinase (AK) and Hypoxanthine-Guanine Phosphoribosyltransferase (HGPRT), as well as a MIX of the two enzymes. Female Balb/c mice were immunized in three doses, and 15 days after the last immunization, animals were infected with S. mansoni. Our results showed that the group MIX presented a reduction in the eggs in feces by 30.74% and 29%, respectively, in the adult worms. The groups AK, HGPRT and MIX could produce IgG1 antibodies, and the groups AK and MIX produced IgE antibodies anti-enzymes and anti-S. mansoni total proteins. The groups AK, HGPRT and MIX induced a reduction in the eosinophils in the peritoneal cavity. Besides, the group AK showed a decrease in the number of hepatic granulomas (41.81%) and the eggs present in the liver (42.30%). Therefore, it suggests that immunization with these enzymes can contribute to schistosomiasis control, as well as help to modulate experimental infection inducing a reduction of physiopathology in the disease.

Increased oyster aquaculture in the Sado Estuary (Portugal): How to ensure ecosystem sustainability?

Aquaculture is one of the fastest growing sectors in the world. However, this may come with a cost, as increasing aquatic production is likely to impose changes in the environment. To ensure ecosystem sustainability, it is essential to think on this larger scale. This study aims to use the Delft3D model suite to evaluate the ecological carrying capacity for bivalve production in the Sado Estuary (Portugal), under present and future conditions (2050). Scenarios for increased oyster production resulted in reductions of chlorophyll a associated with increased nutrient concentrations. In the most extreme production scenario, which considered an increase of 100 ha in production area, a predicted decrease of 90 % in phytoplankton biomass was observed. Climate change (CC) was incorporated as an increase in sea level and water temperature, as well as a reduction in river flow. Under present oyster production conditions, CC revealed contrasting patterns, i.e. an increase in chlorophyll a concentrations and a reduction in nutrients. These results suggest that CC has a positive effect in counteracting the impacts of increased oyster production, however further research is necessary. All scenarios point to reduced dissolved oxygen concentrations, highlighting the need to monitor this parameter. Given the difficulty in defining what are unacceptable impacts to the ecosystem it would be prudent to include a socio-ecological framework in the future, in order to integrate ecosystem services and the perception of local stakeholders.

Conservation and divergence of the G-interfaces of Drosophila melanogaster septins.

Septins possess a conserved guanine nucleotide-binding (G) domain that participates in the stabilization of organized hetero-oligomeric complexes which assemble into filaments, rings and network-like structures. The fruit fly, Drosophila melanogaster, has five such septin genes encoding Sep1, Sep2, Sep4, Sep5 and Pnut. Here, we report the crystal structure of the heterodimer formed between the G-domains of Sep1 and Sep2, the first from an insect to be described to date. A G-interface stabilizes the dimer (in agreement with the expected arrangement for the Drosophila hexameric particle) and this bears significant resemblance to its human counterparts, even down to the level of individual amino acid interactions. On the other hand, a model for the G-interface formed between the two copies of Pnut which occupy the centre of the hexamer, shows important structural differences, including the loss of a highly favourable bifurcated salt-bridge network. Whereas wild-type Pnut purifies as a monomer, the reintroduction of the salt-bridge network results in stabilizing the dimeric interface in solution as shown by size exclusion chromatography and thermal stability measurements. Adaptive steered molecular dynamics reveals an unzipping mechanism for dimer dissociation which initiates at a point of electrostatic repulsion within the switch II region. Overall, the data contribute to a better understanding of the molecular interactions involved in septin assembly/disassembly.

Expression of Yarrowia lipolytica acetyl-CoA carboxylase in Saccharomyces cerevisiae and its effect on in-vivo accumulation of Malonyl-CoA.

Malonyl-CoA is an energy-rich molecule formed by the ATP-dependent carboxylation of acetyl coenzyme A catalyzed by acetyl-CoA carboxylase. This molecule is an important precursor for many biotechnologically interesting compounds such as flavonoids, polyketides, and fatty acids. The yeast Saccharomyces cerevisiae remains one of the preferred cell factories, but has a limited capacity to produce malonyl-CoA compared to oleaginous organisms. We developed a new S. cerevisiae strain with a conditional allele of ACC1, the essential acetyl-CoA carboxylase (ACC) gene, as a tool to test heterologous genes for complementation. Yarrowia lipolytica is an oleaginous yeast with a higher capacity for lipid production than S. cerevisiae, possibly due to a higher capacity to produce malonyl-CoA. Measuring relative intracellular malonyl-CoA levels with an in-vivo biosensor confirmed that expression of Y. lipolytica ACC in S. cerevisiae leads to a higher accumulation of malonyl-CoA compared with overexpression of the native gene from an otherwise identical vector. The higher accumulation was generally accompanied by a decreased growth rate. Concomitant expression of both the homologous and heterologous ACC1 genes eliminated the growth defect, with a marginal reduction of malonyl-CoA accumulation.

Structural Characterization of L-Galactose Dehydrogenase: An Essential Enzyme for Vitamin C Biosynthesis.

In plants, it is well-known that ascorbic acid (vitamin C) can be synthesized via multiple metabolic pathways but there is still much to be learned concerning their integration and control mechanisms. Furthermore, the structural biology of the component enzymes has been poorly exploited. Here we describe the first crystal structure for an L-galactose dehydrogenase [Spinacia oleracea GDH (SoGDH) from spinach], from the D-mannose/L-galactose (Smirnoff-Wheeler) pathway which converts L-galactose into L-galactono-1,4-lactone. The kinetic parameters for the enzyme are similar to those from its homolog from camu camu, a super-accumulator of vitamin C found in the Peruvian Amazon. Both enzymes are monomers in solution and have a pH optimum of 7, and their activity is largely unaffected by high concentrations of ascorbic acid, suggesting the absence of a feedback mechanism acting via GDH. Previous reports may have been influenced by changes of the pH of the reaction medium as a function of ascorbic acid concentration. The structure of SoGDH is dominated by a (ß/α)8 barrel closely related to aldehyde-keto reductases (AKRs). The structure bound to NAD+ shows that the lack of Arg279 justifies its preference for NAD+ over NADP+, as employed by many AKRs. This favors the oxidation reaction that ultimately leads to ascorbic acid accumulation. When compared with other AKRs, residue substitutions at the C-terminal end of the barrel (Tyr185, Tyr61, Ser59 and Asp128) can be identified to be likely determinants of substrate specificity. The present work contributes toward a more comprehensive understanding of structure-function relationships in the enzymes involved in vitamin C synthesis.

Evaluation of future estuarine floods in a sea level rise context.

Reliable predictions of future inundation extent within estuaries require a precise evaluation of future extreme sea levels and the application of accurate numerical models that account for the physical processes driving estuarine hydrodynamics. In this study, a methodology that integrates the estimation of local extreme sea levels with high-resolution numerical modeling was applied to assess the future inundation extent in five estuarine systems located on the Portuguese Coast. The main findings obtained were compared with available results from the popular bathtub approach, that disregards the physical processes driving estuarine hydrodynamics and therefore provide imprecise predictions of inundation extent and associated socio-economic impacts. The inundation extent is revealed to be highly dependent on the extreme sea levels and on the estuarine geomorphology, which controls the propagating long-wave. As the long-wave height is highly attenuated within estuaries that have adjacent low-lying areas, restricted inlets, or extensive tidal flats, the results of this study revealed that the extent of inundation is considerably smaller than that obtained by the bathtub approach. The uncertainties associated with mean sea level rise and the estuarine geomorphological evolution constitute the greatest difficulty in assessing the extent of flooding, posing major challenges to the efficient and sustainable management of estuaries.

Towards engineered yeast as production platform for capsaicinoids.

Capsaicinoids are bioactive alkaloids produced by the chili pepper fruit and are known to be the most potent agonists of the human pain receptor TRPV1 (Transient Receptor Potential Cation Channel Subfamily V Member 1). They are currently produced by extraction from chili pepper fruit or by chemical synthesis. Transfer of the biosynthetic route to a microbial host could enable more efficient capsaicinoid production by fermentation and may also enable the use of synthetic biology to create a diversity of new compounds with potentially improved properties. This review summarises the current state of the art on the biosynthesis of capsaicinoid precursors in baker's yeast, Saccharomyces cerevisiae, and discusses bioengineering strategies for achieving total synthesis from sugar.