Biology subjects

Tsaousis, A. D.

Publications and source records attributed to Tsaousis, A. D..

7 recordsLinked to original sources

bioRxiv2024

Toward Holistic Solutions to Undernutrition: A Comprehensive Preclinical Protocol for Novel Ready-to-Use Therapeutic Foods Testing

Severe acute malnutrition (SAM) affects over 45 million children under five worldwide. Ready-to-Use Therapeutic Foods (RUTFs), the cornerstone of treatment, reach only 30% of children in need due to high production costs and reliance on imports. RUTF formulations developed from local ingredients have shown varying efficacy levels focusing primarily on weight gain, overlooking critical factors like micronutrient status, skeletal development, and gut health. The presented study establishes a comprehensive protocol for preclinical testing of novel RUTF formulations using a validated juvenile rat model replicating key features of malnutrition in children. Beyond the standard anthropometric measurements (body weight, length, and food consumption), bone quality is assessed through micro-computed tomography and mechanical testing, providing insights into microstructure and functionality beyond standard anthropometric measurements. Concurrently, gut microbiome dynamics are analysed using 16S rRNA sequencing coupled with metabolomic profiling of stool and serum to monitor gut health and systemic recovery.By addressing critical gaps in traditional RUTF evaluations and emphasising locally sourced, cost-effective formulations, this protocol offers a transformative framework for developing accessible and impactful malnutrition treatments. The findings generated through this multidisciplinary approach will guide RUTFs optimisation, strengthen their scientific foundation, and pave the way for evidence-based clinical trials to improve global malnutrition treatment strategies.

physiology↗

bioRxiv2024

Local High-Protein, Plant-Based Ready-to-Use Therapeutic Food Enhances Recovery from Malnutrition in Rats

Infant child malnutrition is a major public health issue. We conducted a preclinical study with young rats to mimic the conditions of child malnutrition (combined wasting and stunting) and evaluate recovery using a novel plant-based ready-to-use-therapeutic food (RUTF) formulation. Three-week old female Sprague Dawley rats were assigned to six treatments groups in a 6-week experiment. The treatments included: 1) control balanced diet (CT), 2) A protein-deficient diet to induce malnutrition (MN), 3) and 4) A control balanced diet followed by either commercial RUTF (CT-PM) or a locally produced plant-based RUTF (CT-ChSMS), and 5) and 6) a protein deficient diet followed by either commercial RUTF (MN-PM) or locally produced plant based RUTF (MN-ChSMS), respectively. In treatments 3-6, rats were initially fed either a control-balanced or protein-deficient diet for 3 weeks, followed by 3 weeks of either the commercial or the locally plant-based RUTF. Results showed that rats in the CT-ChSMS group exhibited growth and weight comparable to CT group, while those in the MN-PM group showed no significant improvement compared to the MN group. Notably, rats in the MN-ChSMS group demonstrated significant catch-up growth, whereas those in the MN-PM group did not. Additionally, consumption of ChSMS and PM RUTFs differed significantly. ChSMS RUTF which contained 14% protein over total energy with better amino-acid composition and a higher Protein Digestibility-Corrected Amino Acid Score (PDCAAS), resulted in significantly greater weight gain and length compared to PM RUTF, which contained 10% protein over total energy. These findings indicate that a locally produced, culturally acceptable and affordable plant-based RUTF formulated with high protein quality and quantity may be effective in treating acute and chronic malnutrition in children.

physiology↗

bioRxiv2024

Global Prevalence of Cryptosporidium Infections in Cattle and C. parvum genotype distribution: A Meta-Analysis

BackgroundThe protozoan parasite Cryptosporidium is the causative agent of a severe diarrhoeal disease, called cryptosporidiosis. Cryptosporidium species are capable of infecting a wide range of hosts including humans and livestock. In cattle, cryptosporidiosis is now one of the most important causes of neonatal scour globally, either as a sole agent or co-infecting with other pathogens. Cryptosporidiosis is considered globally endemic, with a prevalence of Cryptosporidium in stool samples from 13% to 93% in European cattle. This disease has a significant economic burden, with costs associated with veterinary diagnosis, medication, increased labour, animal rearing and supplemental nutrition as well as being associated with reduced long-term growth rate in calves, causing huge economic losses in livestock industry. Moreover, cattle act as a zoonotic reservoir for Cryptosporidium parvum, a species that is capable of infecting humans as well. As such, monitoring the prevalence of Cryptosporidium in cattle is important due to the public health risk and financial burden the clinical disease causes. MethodsPublications reporting on the prevalence of Cryptosporidium in cattle were collected from PubMed and Google Scholar. Information regarding the species of Cryptosporidium in positive samples, the genotype of C. parvum found in samples, and the diarrhoeic status of the cattle was collected where available. A total of 279 publications were collected for this meta-analysis from six continents and 65 countries to provide an estimation for global bovine Cryptosporidium prevalence. ResultsA 25.5% global prevalence of Cryptosporidium infection was reported, with C. parvum being the most frequently identified species, particularly the IIa subfamily. Diarrhoea was reported in 14,141 cattle samples, of which 36.0% tested positive for Cryptosporidium. Regarding symptoms, we found that in countries reporting over 50% of diarrhoeic positive cattle, C. parvum was the most common species. ConclusionsContinued monitoring and reporting of Cryptosporidium in cattle are crucial for both public health and economic reasons. Consequently, efforts should focus on underreported regions and the development of control measures to reduce prevalence and limit zoonotic transmission.

microbiology↗

bioRxiv2021

Cross-border investigations on the prevalence and transmission dynamics of Cryptosporidium species in dairy cattle farms in western mainland Europe

Cryptosporidium is comprised an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis. In cattle farms, the incidence of cryptosporidiosis results in high mortality in calves leading to considerable economic loss in the livestock industry. Infected animals may also act as a major reservoir of Cryptosporidium spp., in particular C. parvum, the most common cause of cryptosporidiosis in calves. This poses a significant risk to other farms via breeding centres, to trading of livestock and to human health. This study, funded by the Interreg-2-seas programme, is a part of a global project aimed at strategies to tackle cryptosporidiosis. To reach this target, it was essential to determine whether prevalence was dependent on the studied countries or if the issue was borderless. Indeed, C. parvum occurrence was assessed across dairy farms in certain regions of Belgium, France and the Netherlands. At the same time, the animal-to-animal transmission of the circulating C. parvum subtypes was studied. To accomplish this, 1084 faecal samples, corresponding to 57 dairy-farms from all three countries, were analysed. Well-established protocols amplifying the 18S rDNA and gp60 genes fragments, followed by DNA sequencing, were used for the detection and subtyping C. parvum; the DNA sequences obtained were further characterised using a combination of bioinformatics and phylogenetics methods. Our results show 25.7%, 24.9% and 20.8% prevalence of Cryptosporidium spp. in Belgium, France and the Netherlands respectively. Overall, 93% of the farms were Cryptosporidium positive. The gp60 subtyping demonstrated a significant number of the C. parvum positives belonged to the IIa allelic family, which has been also detected in humans. Consequently, this study highlights how widespread is C. parvum in dairy farms and endorses cattle as a major carrier of zoonotic C. parvum subtypes, which subsequently pose a significant threat to human health.

microbiology↗

bioRxiv2020

A comparative 'omics approach to candidate pathogenicity factor discovery in the brain-eating amoeba Naegleria fowleri

Of the 40 described Naegleria species, only N. fowleri can establish infection in humans, killing almost invariably within two weeks. In the brain, the amoeba performs piece-meal ingestion, or trogocytosis, of brain material causing massive inflammation. Conversely, its close relative Naegleria gruberi, which is used as a laboratory model organism, is non-pathogenic. The exact pathogenicity factors distinguishing N. fowleri from its harmless relatives are unclear. We have here taken an -omics approach to understanding N. fowleri biology and infection at the system level. We provide the first analysis of genomic diversity between strains, finding little conservation in synteny but high conservation in protein complement. We also demonstrate that the N. fowleri genome encodes a similarly complete cellular repertoire to that found in N. gruberi. Our comparative genomic analysis, together with a transcriptomic analysis of low versus high pathogenicity N. fowleri cultured in a mouse infection model, allowed us to construct a model of cellular systems involved in pathogenicity and furthermore provides ~500 novel candidate pathogenicity factors in this currently rare but highly fatal pathogen.

microbiology↗

bioRxiv2019

Ancestral Mitochondrial Protein Secretion Machinery

The type 2 secretion system (T2SS) is present in some Gram-negative eubacteria and used to secrete proteins across the outer membrane. Here we report that certain representative heteroloboseans, jakobids, malawimonads and hemimastigotes unexpectedly possess homologues of core T2SS components. We show that at least some of them are present in mitochondria, and their behaviour in biochemical assays is consistent with the presence of a mitochondrial T2SS-derived system (miT2SS). We additionally identified 23 protein families co-occurring with miT2SS in eukaryotes. Seven of these proteins could be directly linked to the core miT2SS by functional data and/or sequence features, whereas others may represent different parts of a broader functional pathway, possibly also involving the peroxisome. Its distribution in eukaryotes and phylogenetic evidence together indicate that the miT2SS-centred pathway is an ancestral eukaryotic trait. Our findings thus have direct implications for the functional properties of the early mitochondrion.

evolutionary biology↗

bioRxiv2017

Metabolic changes of the host-pathogen environment in a Cryptosporidium infection

Cryptosporidium is an important gut microbe whose contributions towards infant and immunocompromise patient mortality rates are steadily increasing. Current techniques for diagnosing, curing or simply understanding the biology of the parasite are few and far between, relying on a combination of in-silico predictions modelled on a varied and unique group of organisms and medical reports. The development of an in-vitro culture system, using COLO-680N cells, has provided the Cryptosporidium community with the opportunity to expand its toolkit for investigating this disease. One area in particular that is sorely overlooked is the metabolic alterations upon infection. Existing research is extremely limited and has already shown that significant variation can be found between the metabolome of different infected host species. Using a 1H Nuclear Magnetic Resonance approach to metabolomics, we have explored the nature of the mouse gut metabolome as well as providing the first insight into the metabolome of an infected cell line. Through a combination of Partial Least Squares Discriminant Analysis and predictive modelling, we exhibit new and potentially game changing insights into the effects of a Cryptosporidium parvum infection, while verifying the presence of known metabolic changes. Of particular note is the potential contribution of host derived taurine to the diuretic aspects of the disease previously attributed to a solely parasite based alteration of the gut environment. This practical and informative approach can spearhead our understanding of the Cryptosporidium-host metabolic exchange and thus provide novel targets for tackling this deadly parasite.

microbiology↗