Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents

Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults.Pathogenic factors,such as oxidative stress,an increase in acetylcholinesterase activity,mitochondrial dysfunction,genotoxicity,and neuroinflammation are present in this syndrome,which leads to neurodegeneration.Neurodegenerative pathologies such as Alzheimer’s disease are considered late-onset diseases caused by the complex combination of genetic,epigenetic,and environmental factors.There are two main types of Alzheimer’s disease,known as familial Alzheimer’s disease(onset<65 years)and late-onset or sporadic Alzheimer’s disease(onset≥65 years).Patients with familial Alzheimer’s disease inherit the disease due to rare mutations on the amyloid precursor protein(APP),presenilin 1 and 2(PSEN1 and PSEN2)genes in an autosomaldominantly fashion with closely 100%penetrance.In contrast,a different picture seems to emerge for sporadic Alzheimer’s disease,which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology.Importantly,the fundamental pathophysiological mechanisms driving Alzheimer’s disease are interfaced with epigenetic dysregulation.However,the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer’s disease or following injury or stroke in humans.In recent years,there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer’s disease.Through epigenetic mechanisms,such as DNA methylation,non-coding RNAs,histone modification,and chromatin conformation regulation,natural compounds appear to exert neuroprotective effects.While we do not purport to cover every in this work,we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer’s disease-related genes.

Colon Adenocarcinoma in a Retrograde Intussusception: A Case Report and Literature Review

Background: Intussusception is defined as a telescoping of a proximal gastrointestinal segment with its mesentery to a distal one, only 5% occur in adults and in colon the probability that it is caused by a malignant disease is up to 65%. Only 1% occurs in a retrograde manner, the rest occur in an anterograde manner. Aim: Describe the clinical presentation of an intussusception in the adult patient as well as its most frequent causes and possible complications that influence decision making for a definitive treatment. Case Presentation: A 66-year-old woman diagnosed with colon adenocarcinoma who underwent elective transverse colectomy and colonic anastomosis with an incidental finding of a transverse colon tumor in a retrograde intussusception was studied. Conclusion: In any adult patient with an intussusception especially in colon a neoplasia should be suspected and the affected segment should be resected without being reduced due to the risk of perforation and tumor dissemination.

Gravity-Driven Listric Growth Fault and Sedimentation in the Lagoa do Peixe, Rio Grande do Sul Coastal Plain, Brazil

High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However, low frequency GPR surveys to investigate fault-related depositional systems at greater depths are scarce. This survey was designed investigate a > 100 km long linear escarpment that controls the northwest margin of the Lagoa do Peixe, an important lagoon in Rio Grande do Sul Coastal Plain (RGSCP, Brazil). The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;no deformational structure is admitted to exist before. The low frequency GPR (50 MHz, RTA antenna) and geological surveys carried out in the RGSCP showed the existence of a large, gravity-driven listric growth fault controlling the Lagoa do Peixe escarpment and hangingwall sedimentation. The radargrams in four subareas along the Lagoa do Peixe Growth Fault could be interpreted following the seismic expression of rift-related depositional systems. The radargrams enabled to distinguish three main lagoonal deposition radarfacies. The lower lagoonal radarfacies is a convex upward unit, thicker close to growth fault;the radarfacies geometry indicates that fault displacement rate surpasses the sedimentation rate, and its upper stratum is aged ~3500 l4C years BP. The second lagoonal radarfacies is a triangular wedge restricted to the lagoon depocenter, whose geometry indicates that fault displacement and the sedimentation rates kept pace. The upper lagoonal radarfacies is being deposited since 1060 ± 70 l4C years BP, under sedimentation rate higher than fault displacement rate. The results indicate that low frequency GPR surveys can help in investigating fault-related depositional systems in coastal zones. They also point to a new approach in dealing with RGSCP stratigraphy.

Ductal carcinoma in situ within a fibroadenoma:A case report and review of literature

BACKGROUND Fibroadenoma(FA)is the most common tumor found in young women,although it can occur in any age group.Ductal carcinoma in situ(DCIS)that is confined in a FA is rare;it is most frequently reported as an incidental finding.CASE SUMMARY We report a case of DCIS within a FA in a 46-year-old female without cancerrelated personal and family histories.The patient was diagnosed with a breast conglomerate of nodules and was followed for 1 year.In the current control image study,we found suspicious microcalcification,as a new finding,within one of the nodules.Consequently,a core biopsy of the tumor,which appeared hypoechoic,oval,and circumscribed,was performed.The pathological diagnosis was ductal carcinoma in situ within a fibroepithelial lesion.The patient underwent breastconserving surgery and received radiotherapy as well as endocrine therapy(tamoxifen).CONCLUSION We recommend a multidisciplinary approach for adequate treatment and followup.

Chitosan Nanoparticles as Biostimulant in Lettuce (Lactuca sativa L.) Plants

Biodegradable nanoparticles such as chitosan nanoparticles (CSNPs) are used in sustainable agriculture since theyavoid damage to the environment;CSNPs have positive effects such as the accumulation of bioactive compoundsand increased productivity in plants. This study aimed to investigate the impact of applying CSNPs on lettuce,specifically focusing on enzymatic activity, bioactive compounds, and yield. The trial was conducted using a completelyrandomized design, incorporating CSNPs: 0, 0.05, 0.1, 0.2, 0.4, and 0.8 mg mL−1. The doses of 0.4 mg mL−1improve yields up to 24.6% increases and 0.1 mg mL−1 of CSNPs increases total phenols by 31.2% and antioxidantcapacity by 34.6%. In addition, when low concentrations of CSNPs (0.05 and 0.1 mg L−1) were applied, anincrease in catalase was determined. The CSNPs represent a good alternative to be used as a biostimulant in sustainableagriculture because they improve the yield and quality of lettuce by increasing the bioactive compounds.

Secondary Metabolites of Entomopathogenic Fungi, Biological Alternative for the Control of Agricultural Pests and Disease: Present and Perspectives

The use of entomopathogenic fungi (EF) in recent years has been highly effective against the different orders of insects considered pests of agricultural importance and their conidia have been commonly applied, but it has been reported that these are sensitive to the environmental conditions. For this reason, biopesticides products have been formulated based on secondary metabolites, recently. These biomolecules participate as biological control agent, such as: cyclic depsipeptides, amino acids, polyketides, polyphenols and terpenoids, affecting their morphology, life cycle and insect behavior. The use of secondary metabolites of entomopathogenic fungi opens the possibility of application in a more efficient way for the control of agricultural pests in a compatible with the environment and human health;therefore, it is important to know, analyzing the type of molecules, their effects, and their different methods of application.

Gravity Fault Subsidence and Beach Ridges Progradation in Quinta-Cassino (RS) Coastal Plain, Brazil

Ground penetrating radar (GPR) surveys have being applied to investigate very near-surface stratification of sedimentary units in coastal plains and to define their depositional conditions. This paper presents, however, low-frequency GPR survey to investigate fault-related depositional systems at greater depths. The Quinta-Cassino area in the Rio Grande do Sul Coastal Plain (RGSCP, Brazil) shows a wide strandplain that is made off by very long, continuous, and linear geomorphic features (beach ridges). This strandplain extends for ~70 km southward. The beach ridges show low-angle truncations against the Quinta escarpment, and also truncations in the strandplain. The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;previous model assumes that no deformational episode occurred in RGSCP. The geophysical and geological surveys carried out in this area showed the existence of listric fault controlling the beach ridges in the escarpments and hanging-wall blocks. The radargrams could distinguish Pleistocene basement unit anticlockwise rotation, thickening of beach ridges radarfacies close to listric normal faults, and horst structures. These deformational features indicate that the extensional zone of a large-scale gravity-driven structure controlled the mechanical subsidence, the Holocene sedimentation and its stratigraphic and geomorphic features in the Quinta-Cassino area to build up an asymmetric delta. The results point to a new approach in dealing with RGSCP Holocene evolution.

HVSR analysis of pumice sands for sediment depth characterization:A case study for Guadalajara,Mexico

The horizontal to vertical spectral ratio(HVSR)methodology is used here to characterize pumice soils and to image the three-dimensional surface geometry of Guadalajara,Mexico.Similar to other Latin American cities,Guadalajara is exposed to high seismic risk,with the particularity of being the largest urban settlement in Latin America built on pumice soils.Methodology has not yet been tested to characterize subsoil depths in pumice sands.Due to the questionable use of traditional geotechnical tests for the analysis of pumice soils,HVSR provides an alternative for its characterization without altering its fragile and porous structure.In this work,resonance frequency(F0)and peak amplitude(A0)are used to constrain the depth of the major impedance contrast that represents the interface between bedrock and pumice soil.Results were compared with borehole depths and other available geotechnical and geophysical data and show good agreement.One of the profiles estimated on the riverbanks that cross the city,reveals different subsoil thickness that could have an impact on different site responses on riverine areas to an eventual earthquake.Government and academic efforts are combined in this work to characterize depth sediments,an important parameter that impacts the regulations for construction in the city.

Coffee Leaf Rust(Hemileia vastatrix)Disease in Coffee Plants and Perspectives by the Disease Control

Coffee Leaf Rust(CLR)is caused by Hemileia vastatrix in Coffea spp.It is one of the most dangerous phytopathogens for coffee plantations in terms of coffee productivity and coffee cup quality.In this review,we resume the problem of CLR in Mexico and the pathogenesis of H.vastatrix.The review abord plant-pathogen interactions which lead a compatible or incompatible interactions and result in CLR disease or resistance,respectively.The review abord Coffea spp.defense response pathways involved in H.vastatrix pathogenicity.Additionally,current measures to control H.vastatrix proliferation and germination were aborded focused on phytosanitary actions,and biological and chemical control.Finally,new trendlines to reduce the impact of CLR as nanoparticles and nanotechnology were analyzed.

Plant growth and metabolism of exotic and native Crotalaria species for mine land rehabilitation in the Amazon

Despite its enormous benefits,mining is respon-sible for intense changes to vegetation and soil properties.Thus,after extraction,it is necessary to rehabilitate the mined areas,creating better conditions for the establishment of plant species which is challenging.This study evaluated mineral and organic fertilization on the growth,and carbon and nitrogen(N)metabolism of two Crotalaria species[Cro-talaria spectabilis(exotic species)and Crotalaria maypu-rensis(native species from Carajás Mineral Province(CMP)]established on a waste pile from an iron mine in CMP.A control(without fertilizer application)and six fertilization mixtures were tested(i=NPK;ii=NPK+micronutrients;iii=NPK+micronutrients+organic compost;iv=PK;v=PK+micronutrients;vi=PK+micronutrients+organic compost).Fertilization contributed to increased growth of both species,and treatments with NPK and micronutrients had the best results(up to 257%cf.controls),while organic fertilization did not show differences.Exotic Crotalaria had a greater number of nodules,higher nodule dry mass,chlorophyll a and b contents and showed free ammonium as the predominant N form,reflecting greater increments in biomass compared to native species.Although having lower growth,the use of this native species in the rehabilitation of mining areas should be considered,mainly because it has good development and meets current government legislation as an opportunity to restore local biodiversity.

Metal-modulated epitaxy of Mg-doped Al_(0.80)In_(0.20)N-based layer for application as the electron blocking layer in deep ultraviolet light-emitting diodes

This work reports the growth and characterization of p-AlInN layers doped with Mg by plasma-assisted molecular beam epitaxy(PAMBE).AlInN was grown with an Al molar fraction of 0.80 by metal-modulated epitaxy(MME)with a thickness of 180 nm on Si(111)substrates using AlN as buffer layers.Low substrate temperatures were used to enhance the incorporation of indium atoms into the alloy without clustering,as confirmed by X-ray diffraction(XRD).Cathodoluminescence measurements revealed ultraviolet(UV)range emissions.Meanwhile,Hall effect measurements indicated a maximum hole mobility of 146 cm^(2)/(V∙s),corresponding to a free hole concentration of 1.23×10^(19)cm^(−3).The samples were analyzed by X-ray photoelectron spectroscopy(XPS)estimating the alloy composition and extracting the Fermi level by valence band analysis.Mg-doped AlInN layers were studied for use as the electron-blocking layer(EBL)in LED structures.We varied the Al composition in the EBL from 0.84 to 0.96 molar fraction to assess its theoretical effects on electroluminescence,carrier concentration,and electric field,using SILVACO Atlas.The results from this study highlight the importance and capability of producing high-quality Mg-doped p-AlInN layers through PAMBE.Our simulations suggest that an Al content of 0.86 is optimal for achieving desired outcomes in electroluminescence,carrier concentration,and electric field.

Impact of payment source, referral site, and place of residence on outcomes after allogeneic transplantation in Mexico

BACKGROUND The impact of social determinants of health in allogeneic transplant recipients in low-and middle-income countries is poorly described.This observational study analyzes the impact of place of residence,referring institution,and transplant cost coverage(out-of-pocket vs government-funded vs private insurance)on outcomes after allogeneic hematopoietic stem cell transplantation(alloHSCT)in two of Mexico's largest public and private institutions.AIM To evaluate the impact of social determinants of health and their relationship with outcomes among allogeneic transplant recipients in Mexico.METHODS In this retrospective cohort study,we included adolescents and adults≥16 years who received a matched sibling or haploidentical transplant from 2015-2022.Participants were selected without regard to their diagnosis and were sourced from both a private clinic and a public University Hospital in Mexico.Three payment groups were compared:Out-of-pocket(OOP),private insurance,and a federal Universal healthcare program“Seguro Popular”.Outcomes were compared between referred and institution-diagnosed patients,and between residents of Nuevo Leon and out-of-state.Primary outcomes included overall survival(OS),categorized by residence,referral,and payment source.Secondary outcomes encompassed early mortality,event-free-survival,graft-versus-host-relapse-free survival,and non-relapse-mortality(NRM).Statistical analyses employed appropriate tests,Kaplan-Meier method,and Cox proportional hazard regression modeling.Statistical software included SPSS and R with tidycmprsk library.RESULTS Our primary outcome was overall survival.We included 287 patients,n=164 who lived out of state(57.1%),and n=129 referred from another institution(44.9%).The most frequent payment source was OOP(n=139,48.4%),followed by private insurance(n=75,26.1%)and universal coverage(n=73,25.4%).No differences in OS,event-free-survival,NRM,or graft-versus-host-relapse-free survival were observed for patients diagnosed locally vs in another institution,nor patients who lived in-state vs out-of-state.Patients who covered transplant costs through private insurance had the best outcomes with improved OS(median not reached)and 2-year cumulative incidence of NRM of 14%than patients who covered costs OOP(Median OS and 2-year NRM of 32%)or through a universal healthcare program active during the study period(OS and 2-year NRM of 19%)(P=0.024 and P=0.002,respectively).In a multivariate analysis,payment source and disease risk index were the only factors associated with overall survival.CONCLUSION In this Latin-American multicenter study,the site of residence or referral for alloHSCT did not impact outcomes.However,access to healthcare coverage for alloHSCT was associated with improved OS and reduced NRM.

The Beneficial Effects of Components of Garlic (Allium sativum L.) in the Poultry Industry

Plant-based antimicrobial agents are readily available, cost-effective, and exhibit low toxicity, making them promising alternatives in combatting microbial infections. Among these plants, garlic (Allium sativum) stands out for its traditional medicinal use in effectively combating various microorganisms. In the poultry industry, preventing avian virus and bacterial infections is paramount for chicken husbandry. However, using conventional drugs poses potential risks to human health. Garlic, a widely used Asian plant in traditional medicine for various pathologies, has shown potential as an herbal prophylactic remedy against viral and bacterial infections. Recently, researchers explored garlic and its derivatives as a scientific strategy in veterinary practices for diverse purposes, such as improving poultry production characteristics and acting as antibiotic growth promoters. This comprehensive review delves into garlic and its derivatives as preventive and corrective treatments for viral diseases in laying hens and broilers. The paper highlights their potential effectiveness and safety as a natural means to enhance poultry health and welfare while mitigating the risks associated with conventional drug usage in the food industry.

Explainable Artificial Intelligence(XAI)Model for Cancer Image Classification

The use of Explainable Artificial Intelligence(XAI)models becomes increasingly important for making decisions in smart healthcare environments.It is to make sure that decisions are based on trustworthy algorithms and that healthcare workers understand the decisions made by these algorithms.These models can potentially enhance interpretability and explainability in decision-making processes that rely on artificial intelligence.Nevertheless,the intricate nature of the healthcare field necessitates the utilization of sophisticated models to classify cancer images.This research presents an advanced investigation of XAI models to classify cancer images.It describes the different levels of explainability and interpretability associated with XAI models and the challenges faced in deploying them in healthcare applications.In addition,this study proposes a novel framework for cancer image classification that incorporates XAI models with deep learning and advanced medical imaging techniques.The proposed model integrates several techniques,including end-to-end explainable evaluation,rule-based explanation,and useradaptive explanation.The proposed XAI reaches 97.72%accuracy,90.72%precision,93.72%recall,96.72%F1-score,9.55%FDR,9.66%FOR,and 91.18%DOR.It will discuss the potential applications of the proposed XAI models in the smart healthcare environment.It will help ensure trust and accountability in AI-based decisions,which is essential for achieving a safe and reliable smart healthcare environment.

Renewable Polymers in Biomedical Applications:From the Bench to the Market

Polymers from renewable resources have been used for a long time in biomedical applications and found an irreplaceable role in some of them.Their uses have been increasing because of their attractive properties,contributing to the improvement of life quality,mainly in drug release systems and in regenerative medicine.Formulations using natural polymer,nano and microscale particles preparation,composites,blends and chemical modification strategies have been used to improve their properties for clinical application.Although many studies have been carried out with these natural polymers,the way to reach the market is long and only very few of them become commercially available.Vegetable cellulose,bacterial cellulose,chitosan,poly(lactic acid)and starch can be found among the most studied polymers for biological applications,some with several derivatives already established in the market,and others with potential for such.In this scenario this work aims to describe the properties and potential of these renewable polymers for biomedical applications,the routes from the bench to the market,and the perspectives for future developments.

Sodium-glucose cotransporter-2 inhibitors protect tissues via cellular and mitochondrial pathways:Experimental and clinical evidence

Mitochondrial dysfunction is a key driver of cardiovascular disease(CVD)in metabolic syndrome and diabetes.This dysfunction promotes the production of reactive oxygen species(ROS),which cause oxidative stress and inflammation.Angiotensin II,the main mediator of the renin-angiotensin-aldosterone system,also contributes to CVD by promoting ROS production.Reduced activity of sirtuins(SIRTs),a family of proteins that regulate cellular metabolism,also worsens oxidative stress.Reduction of energy production by mitochondria is a common feature of all metabolic disorders.High SIRT levels and 5’adenosine monophosphate-activated protein kinase signaling stimulate hypoxia-inducible factor 1 beta,which promotes ketosis.Ketosis,in turn,increases autophagy and mitophagy,processes that clear cells of debris and protect against damage.Sodiumglucose cotransporter-2 inhibitors(SGLT2i),a class of drugs used to treat type 2 diabetes,have a beneficial effect on these mechanisms.Randomized clinical trials have shown that SGLT2i improves cardiac function and reduces the rate of cardiovascular and renal events.SGLT2i also increase mitochondrial efficiency,reduce oxidative stress and inflammation,and strengthen tissues.These findings suggest that SGLT2i hold great potential for the treatment of CVD.Furthermore,they are proposed as anti-aging drugs;however,rigorous research is needed to validate these preliminary findings.

Rifaximin on epigenetics and autophagy in animal model of hepatocellular carcinoma secondary to metabolic-dysfunction associated steatotic liver disease

BACKGROUND Prevalence of hepatocellular carcinoma(HCC)is increasing,especially in patients with metabolic dysfunctionassociated steatotic liver disease(MASLD).AIM To investigate rifaximin(RIF)effects on epigenetic/autophagy markers in animals.METHODS Adult Sprague-Dawley rats were randomly assigned(n=8,each)and treated from 5-16 wk:Control[standard diet,water plus gavage with vehicle(Veh)],HCC[high-fat choline deficient diet(HFCD),diethylnitrosamine(DEN)in drinking water and Veh gavage],and RIF[HFCD,DEN and RIF(50 mg/kg/d)gavage].Gene expression of epigenetic/autophagy markers and circulating miRNAs were obtained.RESULTS All HCC and RIF animals developed metabolic-dysfunction associated steatohepatitis fibrosis,and cirrhosis,but three RIF-group did not develop HCC.Comparing animals who developed HCC with those who did not,miR-122,miR-34a,tubulin alpha-1c(Tuba-1c),metalloproteinases-2(Mmp2),and metalloproteinases-9(Mmp9)were significantly higher in the HCC-group.The opposite occurred with Becn1,coactivator associated arginine methyltransferase-1(Carm1),enhancer of zeste homolog-2(Ezh2),autophagy-related factor LC3A/B(Map1 Lc3b),and p62/sequestosome-1(p62/SQSTM1)-protein.Comparing with controls,Map1 Lc3b,Becn1 and Ezh2 were lower in HCC and RIF-groups(P<0.05).Carm1 was lower in HCC compared to RIF(P<0.05).Hepatic expression of Mmp9 was higher in HCC in relation to the control;the opposite was observed for p62/Sqstm1(P<0.05).Expression of p62/SQSTM1 protein was lower in the RIF-group compared to the control(P=0.024).There was no difference among groups for Tuba-1c,Aldolase-B,alpha-fetoprotein,and Mmp2(P>0.05).miR-122 was higher in HCC,and miR-34a in RIF compared to controls(P<0.05).miR-26b was lower in HCC compared to RIF,and the inverse was observed for miR-224(P<0.05).There was no difference among groups regarding miR-33a,miR-143,miR-155,miR-375 and miR-21(P>0.05).CONCLUSION RIF might have a possible beneficial effect on preventing/delaying liver carcinogenesis through epigenetic modulation in a rat model of MASLD-HCC.

The Nikola Tesla Constant and Its Relation to the Circumference Inscribed in a Square

This research work relates the surface of a square and the area circumscribed by a circle, resulting in a value called Nikola Tesla constant. This constant starts with the calculation of the areas of the square and the inscribed circle, giving a ratio of 9/40 and from which a residual area of the area proportions of the geometric figures described is obtained. Plotting smooth curves, particularly those in round shapes, can be represented efficiently with the use of Nikola Tesla constant, reducing complex mathematical calculus.

Distribution and Relation of Primes with Tesla Numbers 3, 6, and 9

This work presents a different approach to twin primes, an approach from the perspective of the Tesla numbers and gives a refresh and new observation of twin primes that could lead us to an answer to the Twin Prime Conjecture problem. We expose a peculiar relation between twin primes and the generation of prime numbers with Tesla numbers. Tesla numbers seem to be present in so many domains like time, vibration and frequency [1], and the space between twin primes is not the exception. Let us say that twin primes are more than just prime numbers plus 2 or minus 2, and Tesla numbers are more involved with twin primes than we think, and hopefully, this approach give us a better understanding of the distribution of the twin pairs.

The first record of dermochelyid turtles in the Eocene of Tierra del Fuego:new insights on the evolution of the Weddellian faunas

The Antarctic Paleogene marine fossil record has been the key to reconstructing the evolution of the Weddellian Sea and final dismemberment of Southern Gondwana.In this context,Eocene marine vertebrates from Seymour(Marambio)Island have provided valuable information.We present the first Eocene record of marine reptiles from the southern Atlantic Coast of South America.This corresponds to several postcranial turtle remains represented by a proximal end of the right humerus,three caudal and one thoracic vertebrae,a fragment of the left pubis,and ten ossicles of the dorsal carapace,coming from the Leticia Formation(late-mid Eocene)at Cabo Tiburones,Tierra del Fuego,Argentina.These materials show severalfeatures such as the size and general morphology of the humerus and vertebrae,and the presence of relatively small,irregular,smooth,and unkeeled ossicles,which allow us to assign them to Dermochelyidae indet.Dermochelyids are a cosmopolitan group ofcryptodiran turtles,registered from the late Cretaceous up to the recent,with some physiological-biological peculiarities(e.g.,endothermy and an exclusive jellyfish-based diet)and characterized by the presence of an osseous carapace formed by ossicles.The new finding from the Leticia Formation is an addition to the scarce and extremely fragmentary record of Eocene dermochelyids from the southern seas like those from the La Meseta and Submeseta formations(Antarctica)and the Waihao and Burnside formations(New Zealand).This new information allows us to discuss the presence of these turtles in such high latitudes in the past and its implication in the evolution of the Weddellian fauna.