scholarly journals The Cost of Metabolic Interactions in Symbioses between Insects and Bacteria with Reduced Genomes

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Nana Y. D. Ankrah ◽  
Bessem Chouaia ◽  
Angela E. Douglas
Keyword(s):  
Metabolic Cost ◽  
Essential Amino Acids ◽  
Genome Reduction ◽  
Bacterial Symbionts ◽  
Relaxed Selection ◽  
Content Type ◽  
Genome Data ◽  
Metabolic Functions ◽  
Metabolite Exchange ◽  
Metabolic Models

ABSTRACTVarious intracellular bacterial symbionts that provide their host with essential nutrients have much-reduced genomes, attributed largely to genomic decay and relaxed selection. To obtain quantitative estimates of the metabolic function of these bacteria, we reconstructed genome- and transcriptome-informed metabolic models of three xylem-feeding insects that bear two bacterial symbionts with complementary metabolic functions: a primary symbiont,Sulcia, that has codiversified with the insects, and a coprimary symbiont of distinct taxonomic origin and with different degrees of genome reduction in each insect species (Hodgkiniain a cicada,Baumanniain a sharpshooter, andSodalisin a spittlebug). Our simulations reveal extensive bidirectional flux of multiple metabolites between each symbiont and the host, but near-complete metabolic segregation (i.e., near absence of metabolic cross-feeding) between the two symbionts, a likely mode of host control over symbiont metabolism. Genome reduction of the symbionts is associated with an increased number of host metabolic inputs to the symbiont and also reduced metabolic cost to the host. In particular,SulciaandHodgkiniawith genomes of ≤0.3 Mb are calculated to recycle ∼30 to 80% of host-derived nitrogen to essential amino acids returned to the host, whileBaumanniaandSodaliswith genomes of ≥0.6 Mb recycle 10 to 15% of host nitrogen. We hypothesize that genome reduction of symbionts may be driven by selection for increased host control and reduced host costs, as well as by the stochastic process of genomic decay and relaxed selection.IMPORTANCECurrent understanding of many animal-microbial symbioses involving unculturable bacterial symbionts with much-reduced genomes derives almost entirely from nonquantitative inferences from genome data. To overcome this limitation, we reconstructed multipartner metabolic models that quantify both the metabolic fluxes within and between three xylem-feeding insects and their bacterial symbionts. This revealed near-complete metabolic segregation between cooccurring bacterial symbionts, despite extensive metabolite exchange between each symbiont and the host, suggestive of strict host controls over the metabolism of its symbionts. We extended the model analysis to investigate metabolic costs. The positive relationship between symbiont genome size and the metabolic cost incurred by the host points to fitness benefits to the host of bearing symbionts with small genomes. The multicompartment metabolic models developed here can be applied to other symbioses that are not readily tractable to experimental approaches.

scholarly journals Cooperative Metabolism in a Three-Partner Insect-Bacterial Symbiosis Revealed by Metabolic Modeling

2017 ◽  
Vol 199 (15) ◽  
Author(s):  
Nana Y. D. Ankrah ◽  
Junbo Luan ◽  
Angela E. Douglas
Keyword(s):  
Amino Acids ◽  
In Silico ◽  
Metabolic Modeling ◽  
Essential Amino Acids ◽  
Intracellular Bacteria ◽  
Metabolic Function ◽  
Bacterial Symbionts ◽  
Content Type ◽  
Host Growth ◽  
Hamiltonella Defensa

ABSTRACT An important factor determining the impact of microbial symbionts on their animal hosts is the balance between the cost of nutrients consumed by the symbionts and the benefit of nutrients released back to the host, but the quantitative significance of nutrient exchange in symbioses involving multiple microbial partners has rarely been addressed. In this study on the association between two intracellular bacterial symbionts, “Candidatus Portiera aleyrodidarum” and “Candidatus Hamiltonella defensa,” and their animal host, the whitefly Bemisia tabaci, we apply metabolic modeling to investigate host-symbiont nutrient exchange. Our in silico analysis revealed that >60% of the essential amino acids and related metabolites synthesized by “Candidatus Portiera aleyrodidarum” are utilized by the host, including a substantial contribution of nitrogen recycled from host nitrogenous waste, and that these interactions are required for host growth. In contrast, “Candidatus Hamiltonella defensa” retains most or all of the essential amino acids and B vitamins that it is capable of synthesizing. Furthermore, “Candidatus Hamiltonella defensa” suppresses host growth in silico by competition with “Candidatus Portiera aleyrodidarum” for multiple host nutrients, by suppressing “Candidatus Portiera aleyrodidarum” growth and metabolic function, and also by consumption of host nutrients that would otherwise be allocated to host growth. The interpretation from these modeling outputs that “Candidatus Hamiltonella defensa” is a nutritional parasite could not be inferred reliably from gene content alone but requires consideration of constraints imposed by the structure of the metabolic network. Furthermore, these quantitative models offer precise predictions for future experimental study and the opportunity to compare the functional organization of metabolic networks in different symbioses. IMPORTANCE The metabolic functions of unculturable intracellular bacteria with much reduced genomes are traditionally inferred from gene content without consideration of how the structure of the metabolic network may influence flux through metabolic reactions. The three-compartment model of metabolic flux between two bacterial symbionts and their insect host constructed in this study revealed that one symbiont is structured to overproduce essential amino acids for the benefit of the host, but the essential amino acid production in the second symbiont is quantitatively constrained by the structure of its network, rendering it “selfish” with respect to these nutrients. This study demonstrates the importance of quantitative flux data for elucidation of the metabolic function of symbionts. The in silico methodology can be applied to other symbioses with intracellular bacteria.

scholarly journals Sequence of a Coxiella endosymbiont of the tick Amblyomma nuttalli suggests a pattern of convergent genome reduction in the Coxiella genus

2020 ◽  
Author(s):  
Tiago Nardi ◽  
Emanuela Olivieri ◽  
Edward Kariuki ◽  
Davide Sassera ◽  
Michele Castelli
Keyword(s):  
Coxiella Burnetii ◽  
Phylogenetic Analyses ◽  
Genome Reduction ◽  
Metabolic Profiles ◽  
The Novel ◽  
Bacterial Symbionts ◽  
Human Pathogen ◽  
Host Genus ◽  
Supportive Role ◽  
Genus One

Abstract Ticks require bacterial symbionts for the provision of necessary compounds that are absent in their hematophagous diet. Such symbionts are frequently vertically transmitted and, most commonly, belong to the Coxiella genus, which also includes the human pathogen Coxiella burnetii. This genus can be divided in four main clades, presenting partial but incomplete co-cladogenesis with the tick hosts. Here we report the genome sequence of a novel Coxiella, endosymbiont of the African tick Amblyomma nuttalli, and the ensuing comparative analyses. Its size (~1 Mb) is intermediate between symbionts of Rhipicephalus species and other Amblyomma species. Phylogenetic analyses show that the novel sequence is the first genome of the B clade, the only one for which no genomes were previously available. Accordingly, it allows to draw an enhanced scenario of the evolution of the genus, one of parallel genome reduction of different endosymbiont lineages, which are now at different stages of reduction from a more versatile ancestor. Gene content comparison allows to infer that the ancestor could be reminiscent of Coxiella burnetii. Interestingly, the convergent loss of mismatch repair could have been a major driver of such reductive evolution. Predicted metabolic profiles are rather homogenous among Coxiella endosymbionts, in particular vitamin biosynthesis, consistently with a host-supportive role. Concurrently, similarities among Coxiella endosymbionts according to host genus and despite phylogenetic unrelatedness hint at possible host-dependent effects.

Cañihua (Chenopodium pallidicaule Aellen) a promising superfood in food industry: a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jerry Fredy Gomez Cahuata ◽  
Yessica Estefany Rosas-Quina ◽  
Erika Pachari Vera
Keyword(s):  
Food Industry ◽  
Unsaturated Fatty Acids ◽  
Protein Quality ◽  
Current Knowledge ◽  
Scientific Information ◽  
Essential Amino Acids ◽  
High Concentration ◽  
Content Type ◽  
Functional Value ◽  
Potential Applications

Purpose The purpose of this paper is to divulge the current knowledge about the nutritional and functional characteristics of Cañihua (Chenopodium pallidicaule Aellen), in addition to its potential applications in the food industry since research studies related to it are still limited compared to other cereals of greater diffusion. Design/methodology/approach The scientific information was collected from Web of Science, Scopus and Google Scholar databases, using keywords such as nutrition value of Chenopodium pallidicaule, amaranth and pseudocereals. Consistent information was selected according to its relevance, year of publication and accuracy with the topic. A total of 49 research papers were selected. Findings Cañihua is a grain with high nutritional potential, considered a superfood because it has a high protein quality, a balanced composition of essential amino acids and unsaturated fatty acids, with a high concentration of linoleic and oleic acid. Besides, it has a good level of bioactive compounds with high antioxidant capacity. However, its production and consumption are limited outside its area of origin, although its cultivation is possible under harsh conditions. Originality/value This paper, through a systematic bibliographic review, highlights the potential of cañihua to be considered in the development of food products with high nutritional and functional value. The information compiled will help researchers and professionals become aware of the importance of this grain and join forces in its processing and enhancement of its attributes.

scholarly journals Draft Genome Sequences for Five Photorhabdus Bacterial Symbionts of Entomopathogenic Heterorhabditis Nematodes Isolated from India

2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Vishal Singh Somvanshi ◽  
Bhumika Dubay ◽  
Jyoti Kushwah ◽  
Sivakumar Ramamoorthy ◽  
Udayakumar S. Vishnu ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Draft Genome ◽  
Insecticidal Protein ◽  
Bacterial Symbionts ◽  
Genome Sequences ◽  
Content Type ◽  
Protein Toxins ◽  
Insect Pathogens

Photorhabdus bacteria exhibit contrasting lifestyles; they are virulent insect pathogens but symbionts of the entomopathogenic Heterorhabditis nematodes. Photorhabdus genomes encode several secondary metabolites and insecticidal protein toxins.

scholarly journals Genome Reduction and Relaxed Selection is Associated with the Transition to Symbiosis in the Basidiomycete Genus Podaxis

2021 ◽  
Author(s):  
Benjamin H. Conlon ◽  
Cene Gostinčar ◽  
Janis Fricke ◽  
Nina B. Kreuzenbeck ◽  
Jan-Martin Daniel ◽  
...  
Keyword(s):  
Genome Reduction ◽  
Relaxed Selection

scholarly journals Nutritional quality evaluation of Whitemouth croaker (Micropogonias furnieri) protein isolate

2014 ◽  
Vol 44 (2) ◽  
pp. 134-143
Author(s):  
William Renzo Cortez-Vega ◽  
Irene Rodrigues Freitas ◽  
Sandriane Pizato ◽  
Carlos Prentice
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Nutritional Quality ◽  
Troponin I ◽  
Essential Amino Acids ◽  
Protein Isolate ◽  
Content Type ◽  
Sds Page ◽  
Apparent Bioavailability

Purpose – The purpose of this study was to isolate Whitemouth croaker protein by alkaline solubilization process and evaluate their nutritional quality to evaluate the bioavailability of essential amino acids. Design/methodology/approach – The proximate composition, essential amino acid composition, in vitro digestibility, apparent bioavailability, chemical score of amino acids and SDS-PAGE were determined for the isolated croaker proteins. Findings – The isolated protein showed a high level of protein 92.21 percent and low amount of lipids 0.57 percent. The protein is rich in lysine and leucine, 108.73 and 96.75 mg/g protein, respectively. The protein isolate had high digestibility, 94.32 percent, which indicates proper utilization of this protein source, while the tryptophan had lower bioavailability (12.58 mg amino acid/mg protein). The high chemical scores were found for the amino acids lysine, methionine+cysteine (6.79 and 5.14). SDS-PAGE of proteins extracted showed appearance of the heavy chain of myosin (220 kDa), actin (50 kDa) and other fractions, with molecular weight between 20 and 50 kDa, such as troponin I, C and T. Originality/value – The products obtained from croaker muscle can be incorporated as a high value supplements in human diets. The isolated protein exhibited a high content of essential amino acids and digestibility, indicating that the protein has a high nutritional quality.

Drought-tolerant Bambara groundnuts as future food: a comprehensive review of its properties and applications in food

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liew-Phing Pui ◽  
Wen-Chian Tan ◽  
Ianne Kong ◽  
Choon-Hui Tan
Keyword(s):  
Positive Impact ◽  
Food Products ◽  
Essential Amino Acids ◽  
Fermented Milk ◽  
Bambara Groundnut ◽  
Bulking Agents ◽  
Chemical Compositions ◽  
Content Type ◽  
Nutrient Density ◽  
Drought Tolerant

PurposeThis review provides an overview of the applications of Bambara groundnuts in various food products. The genetic diversity, physical properties and chemical compositions of the crop are also elucidated.Design/methodology/approachThis paper critically reviewed the physicochemical properties and applications of Bambara groundnuts from recent literature.FindingsBambara groundnut (Vigna subterranea) is a drought-tolerant crop from West Africa that contains not only carbohydrates and fats but is also high in protein. The cultivars of Bambara groundnut can be distinguished by the colours of seeds, which range from red, blue-eye, brown and black-eye. Bambara groundnuts contain carbohydrate (57–67%), protein (15–25%), fat (4–8%), fibre (1.4–1.5%) and ash (2.9–4%). As a percentage of protein, the essential amino acids, lysine, methionine and cysteine are relatively high in Bambara groundnuts. Meanwhile, linoleic, palmitic and linolenic acids are the fatty acids present in this crop.Practical implicationsSeveral studies have shown that Bambara groundnuts can be used as fat substitutes, emulsifiers, water binders, bulking agents and thickeners due to its water and oil absorption properties, gelling, pasting, emulsifying and foaming abilities. Bambara groundnuts are used in the development of many intermediate or final products like flour blend, cookies, bread and fermented milk. It has a positive impact on the overall proximate, functional, mineral and amino acid profiles of the food products.Originality/valueDespite its high nutrient density, Bambara groundnuts are an underutilised legume due to unavailability and lack of knowledge among consumers on its benefits. There is a need to promote the use of Bambara groundnuts as a future food.

scholarly journals Fitness Cost of Aflatoxin Production inAspergillus flavusWhen Competing with Soil Microbes Could Maintain Balancing Selection

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Milton T. Drott ◽  
Tracy Debenport ◽  
Steven A. Higgins ◽  
Daniel H. Buckley ◽  
Michael G. Milgroom
Keyword(s):  
Aspergillus Flavus ◽  
Soil Microbes ◽  
Balancing Selection ◽  
Natural Habitat ◽  
Metabolic Cost ◽  
Aflatoxin Production ◽  
Amplicon Sequencing ◽  
Selective Advantage ◽  
Content Type ◽  
Evolutionary Forces

ABSTRACTSelective forces that maintain the polymorphism for aflatoxigenic and nonaflatoxigenic individuals ofAspergillus flavusare largely unknown. As soils are widely considered the natural habitat ofA. flavus, we hypothesized that aflatoxin production would confer a fitness advantage in the soil environment. To test this hypothesis, we usedA. flavusDNA quantified by quantitative PCR (qPCR) as a proxy for fitness of aflatoxigenic and nonaflatoxigenic field isolates grown in soil microcosms. Contrary to predictions, aflatoxigenic isolates had significantly lower fitness than did nonaflatoxigenic isolates in natural soils across three temperatures (25, 37, and 42°C). The addition of aflatoxin to soils (500 ng/g) had no effect on the growth ofA. flavus. Amplicon sequencing showed that neither the aflatoxin-producing ability of the fungus nor the addition of aflatoxin had a significant effect on the composition of fungal or bacterial communities in soil. We argue that the fitness disadvantage of aflatoxigenic isolates is most likely explained by the metabolic cost of producing aflatoxin. Coupled with a previous report of a selective advantage of aflatoxin production in the presence of some insects, our findings give an ecological explanation for balancing selection resulting in persistent polymorphisms in aflatoxin production.IMPORTANCEAflatoxin, produced by the fungusAspergillus flavus, is an extremely potent hepatotoxin that causes acute toxicosis and cancer, and it incurs hundreds of millions of dollars annually in agricultural losses. Despite the importance of this toxin to humans, it has remained unclear what the fungus gains by producing aflatoxin. In fact, not all strains ofA. flavusproduce aflatoxin. Previous work has shown an advantage to producing aflatoxin in the presence of some insects. Our current work demonstrates the first evidence of a disadvantage toA. flavusin producing aflatoxin when competing with soil microbes. Together, these opposing evolutionary forces could explain the persistence of both aflatoxigenic and nonaflatoxigenic strains through evolutionary time.

Processing and utilization of snail meat in alleviating protein malnutrition in Africa: a review

2020 ◽  
Vol 50 (6) ◽  
pp. 1085-1097
Author(s):  
Samuel Ayofemi Olalekan Adeyeye ◽  
Olusola Timothy Bolaji ◽  
Titilope Adebusola Abegunde ◽  
Taofeek Olawale Adesina
Keyword(s):  
Rural Areas ◽  
Whooping Cough ◽  
Kidney Diseases ◽  
Economic Value ◽  
Meat Products ◽  
Essential Amino Acids ◽  
Antimicrobial Activities ◽  
Protein Malnutrition ◽  
African Countries ◽  
Content Type

Purpose This study aims to review processing and utilization of snail meat in alleviating protein malnutrition in Africa. Most countries in Africa are faced with a major challenge of protein malnutrition as a result of high cost of animal proteins. This has encouraged more research works in the use of wild or game meat to meet the much-needed animal proteins. Design/methodology/approach Previous literatures on the above subject matter were reviewed. In many African countries, the use of snails, rodents and other small livestock in the wild could help in improving the nutritional needs of the people in both urban and rural areas, as well as adding economic value through income generation to the local people. Findings Snails are very rich in dietary protein, low in fat and cholesterol and are good sources of iron, magnesium, calcium and zinc. Previous studies showed that snail meat contains 70 per cent of water and its dry matter contains high amounts of essential amino acids such as lysine, leucine, arginine and tryptophan. Research studies have shown that snail contains calcium orthophosphate, a chemical substrate that could alleviate and reduce kidney diseases. Also, the glandular substances found in edible snails were found to have antimicrobial activities that cause agglutination of certain bacteria, which could be used against some ailments like whooping cough. As snail meat products have high nutritional value, spoilage sets in after one or two days after harvesting, and therefore, the preservation of snail meat has become a major concern to farmers, processors and consumers. Several preservation techniques could be adopted, which include smoking, sun drying, convectional drying and the use of natural or artificial preservatives. These methods have been found to reduce microbial load of snail meat and help to extend shelf life and keeping quality of snail meat. Originality/value This review X-rayed the importance of snail meat in the human diet and how this could be explored to enhance protein nutrition in developing countries.

scholarly journals Draft Genome Sequence of the Industrially Significant Bacterium Pseudomonas fluorescens ATCC 13525

2018 ◽  
Vol 7 (17) ◽  
Author(s):  
M. J. Meier ◽  
R. M. Subasinghe ◽  
L. A. Beaudette
Keyword(s):  
Antibiotic Resistance ◽  
Pseudomonas Fluorescens ◽  
Virulence Factors ◽  
Draft Genome ◽  
Antibiotic Resistance Genes ◽  
Strain Atcc ◽  
Negative Bacterium ◽  
Gram Negative ◽  
Content Type ◽  
Metabolic Functions

Pseudomonas fluorescens is a Gram-negative bacterium with versatile metabolic functions and potential industrial uses. We sequenced P. fluorescens strain ATCC 13525 with the goal of determining virulence factors and antibiotic resistance genes to predict the potential impacts on human and environmental health in the event of exposure.

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