Artificial intelligence and high-resolution anoscopy: automatic identification of anal squamous cell carcinoma precursors using a convolutional neural network.

BACKGROUND: High-resolution anoscopy (HRA) is the gold standard for detecting anal squamous cell cancer (ASCC) precursors. Although it is superior to other diagnostic methods, particularly cytology, the visual identification of areas suspected of having high-grade squamous intraepithelial lesions remains difficult. Convolutional neural networks (CNNs) have shown great potential for assessing endoscopic images. The aim of the present study was to develop a CNN-based system for automatic detection and differentiation of HSIL versus LSIL in HRA images. METHODS: A CNN was developed based on 78 HRA exams from a total of 71 patients who underwent HRA at a single high-volume center (GH Paris Saint-Joseph, Paris, France) between January 2021 and January 2022. A total of 5026 images were included, 1517 images containing HSIL and 3509 LSIL. A training dataset comprising 90% of the total pool of images was defined for the development of the network. The performance of the CNN was evaluated using an independent testing dataset comprising the remaining 10%. The sensitivity, specificity, accuracy, positive and negative predictive values, and area under the curve (AUC) were calculated. RESULTS: The algorithm was optimized for the automatic detection of HSIL and its differentiation from LSIL. Our model had an overall accuracy of 90.3%. The CNN had sensitivity, specificity, positive and negative predictive values of 91.4%, 89.7%, 80.9%, and 95.6%, respectively. The area under the curve was 0.97. CONCLUSIONS: The CNN architecture for application to HRA accurately detected precursors of squamous anal cancer. Further development and implementation of these tools in clinical practice may significantly modify the management of these patients.

The effect of agricultural intensification and water-locking on the world's largest coastal lagoonal system.

The palaeolimnological conditions of Mirim Lagoon, a large coastal shallow lagoon under the influence of historical human impacts related to the development of the primary sector of the economy were reconstructed. The first significant human impact consisted of locking the estuarine system to induce the transition from brackish to freshwater conditions. During this transition, the sedimentation rate consistently increased from pre-disturbance values of 0.25 cm yr-1 to >1 cm yr-1. A concomitant increase in nitrogen and carbon values was recorded indicating a related eutrophication process. The highest nutrient levels were achieved during the 1990s after the incorporation of cutting-edge technologies for agricultural production such as high-yielding varieties of rice resistant to climate variability and pests, and the use of inorganic fertilisers, pesticides and water supply controlled by irrigation. After 2011, the soybean production boosted and the area cultivated with this oilseed equalled the area of rice paddies, i.e., 2 × 105 ha. A sharp decrease in δ13C from -19 to -24‰ and in δ15N from 6 to 2‰ were observed in the sedimentary record, indicating a major shift in the composition of the organic matter after the agricultural intensification. Trace elements Cr, Cu, Ni and Zn showed a high positive correlation with Al and Fe, and enrichment factors near 1, indicating a natural and terrigenous source of these elements and also unpolluted conditions. However, the increase of As after 1990 and the positive correlation with Pb was associated with agricultural practices. All elemental ratios (K/Al, Ti/Al and V/Cr) showed constant pre-disturbance trends and a turning point ca. the 1990s. Microplastics were detected from the beginning of the 1990s and increased towards recent sediments, thus corroborating an anthropogenically impacted scenario. Therefore, the development of the primary sector of the economy exerted clear impacts on the environmental quality of the system.

Development and characterization of a carvacrol nanoemulsion and evaluation of its antimicrobial activity against selected food-related pathogens.

Carvacrol has been recognized as an efficient growth inhibitor of food pathogens. However, carvacrol oil is poorly water-soluble and can be oxidized, decomposed or evaporated when exposed to the air, light, or heat. To overcome these limitations, a carvacrol nanoemulsion was developed and its antimicrobial activity against food pathogens evaluated in this study. The nanoemulsion containing 3% carvacrol oil, 9% surfactants (HLB 11) and 88% water, presented good stability over a period of 90 days. In general, the carvacrol nanoemulsion (MIC: 256 µg ml-1 for E. coli and Salmonella spp., 128 µg ml-1 for Staphylococcus aureus and Pseudomonas aeruginosa) exhibited improved antimicrobial activity compared to the free oil. The carvacrol nanoemulsion additionally displayed bactericidal activity against Escherichia coli, P. aeruginosa and Salmonella spp. Therefore, the results of this study indicated that carvacrol oil nanoemulsions can potentially be incorporated into food formulations, wherein their efficacy for the prevention and control of microbial growth could be evaluated.

Diverse mobilome of Dichotomius (Luederwaldtinia) schiffleri (Coleoptera: Scarabaeidae) reveals long-range horizontal transfer events of DNA transposons.

Transposable elements (TEs) are mobile DNA sequences that are able to move from one genomic location to another. These selfish elements are known as genomic parasites, since they hijack the host molecular machinery to generate new copies of themselves. The mobilization of TEs can be seen as a natural mutagen because new TE copies can insert into different loci and impact host genomic structure through different mechanisms. Although our knowledge about TEs is improving with new genomes available, there is still very limited data about the mobilome of species from the Coleoptera order, the most diverse order of insects, including species from the Scarabaeidae family. Therefore, the main goal of this study was to characterize the mobilome of D. (Luederwaldtinia) schiffleri, based on low-coverage genome sequencing, and reconstruct their evolutionary history. We used a combination of four different approaches for TE characterization and maximum likelihood phylogenetic analysis to study their evolution. We found a large and diverse mobilome composed of 38 TE superfamilies, 20 DNA transposon and 18 retrotransposons, accounting for 21% of the genome. Moreover, we found a number of incongruences between the TE and host phylogenetic trees in three DNA transposon TE superfamilies, which represents five TE families, suggesting possible horizontal transfer events between highly divergent taxa. In summary, we found an abundant and diverse mobilome and a number of horizontal transfer events that have shaped the evolutionary history of this species.

Pleural mesothelioma and lung cancer: the role of asbestos exposure and genetic variants in selected iron metabolism and inflammation genes.

Two of the major cancerous diseases associated with asbestos exposure are malignant pleural mesothelioma (MPM) and lung cancer (LC). In addition to asbestos exposure, genetic factors have been suggested to be associated with asbestos-related carcinogenesis and lung genotoxicity. While genetic factors involved in the susceptibility to MPM were reported, to date the influence of individual genetic variations on asbestos-related lung cancer risk is still poorly understood. Since inflammation and disruption of iron (Fe) homeostasis are hallmarks of asbestos exposure affecting the pulmonary tissue, this study aimed at investigating the association between Fe-metabolism and inflammasome gene variants and susceptibility to develop LC or MPM, by comparing an asbestos-exposed population affected by LC with an "asbestos-resistant exposed population". A retrospective approach similar to our previous autopsy-based pilot study was employed in a novel cohort of autoptic samples, thus giving us the possibility to corroborate previous findings obtained on MPM by repeating the analysis in a novel cohort of autoptic samples. The protective role of HEPH coding SNP was further confirmed. In addition, the two non-coding SNPs, either in FTH1 or in TF, emerged to exert a similar protective role in a new cohort of LC exposed individuals from the same geographic area of MPM subjects. No association was found between NLRP1 and NLRP3 polymorphisms with susceptibility to develop MPM and LC. Further research into a specific MPM and LC "genetic signature" may be needed to broaden our knowledge of the genetic landscape attributed to result in MPM and LC.

Elbow Joint Angle Estimation with Surface Electromyography Using Autoregressive Models.

This paper presents a method to estimate the elbow joint angle from surface electromyography (sEMG) measurements of biceps, triceps and brachioradialis. This estimation is of major importance for the design of human robot interfaces based on sEMG. It is also relevant to model the muscular system and to design biomimetic mechanisms. However, the processing and interpretation of electromyographic signals is challenging due to nonlinearities, unmodeled muscle dynamics, noise and interferences. In order to determine an estimation model and a calibration procedure for the model parameters, a set of experiments were carried out with six subjects. The experiments consisted of series of continuous (cyclical) and discrete elbow flexo-extensions with three different loads (i.e. 0 kg, 1.5kg and 3 kg). The sEMG data from the biceps brachii, triceps brachii and brachioradialis and the joint angle were recorded. Four different modeling techniques were evaluated: State Space (SS), Autoregressive with Exogenous Input (ARX), Autoregressive Moving-Average with Exogenous Input (ARMAX), Autoregressive Integrated Moving-Average with Exogenous Input (ARIMAX). After the model was selected, a second experiment was performed in order to validate the estimation procedure. The results show a procedure to estimate the EMG-to-angle relation with high correlation and low meansquare- root errors with respect to the measured angle data.

Curva de crescimento em altura na cernelha de equinos da raça Mangalarga Marchador considerando-se heterocedasticidade / Growth curve for height at withers of Mangalarga Marchador horses with heterocedasticity

Objetivou-se, com este estudo, avaliar o ajuste dos modelos de Brody, Gompertz, Logístico e Von Bertalanffy aos dados de altura na cernelha de equinos Mangalarga Marchador, ponderando pelo inverso da variância, a fim de selecionar o melhor modelo e predizer sobre o crescimento e a maturidade dos animais dessa raça. Foram utilizados dados de 230 equinos dos seis aos 176 meses de idade, os quais foram divididos por sexo e em 16 classes de idade. Os modelos estudados foram comparados segundo os avaliadores de qualidade: coeficiente de determinação (R2); desvio padrão residual (DPR) e critério de informação de Akaike (AIC). A estimação dos parâmetros dos modelos foi realizada pelo método de mínimos quadrados ponderado no software R. Todos os modelos avaliados se mostraram adequados para descrever a curva de crescimento em ambos os sexos. Perante os avaliadores utilizados, o modelo Logístico foi o mais adequado para descrever as curvas de crescimento em altura na cernelha nos dois sexos da raça Mangalarga Marchador. Observou-se também um crescimento acelerado nos primeiros meses de idade. Os animais machos atingiram uma altura adulta maior, porém as fêmeas são mais precoces, pois apresentaram maior estimativa para o índice de maturidade.(AU)

This work aimed to evaluate the fit of models Brody, Gompertz, Logistic and Von Bertalanffy to height at the withers of Mangalarga Marchador horses, weighed by the inverse of variance, in order to select the best model and predict growth and maturity of this breed pf animals. We used data of 230 equines from 06 to 176 months of age who were divided by sex and 16 age classes. The models were compared according to the quality assessors: coefficient of determination (R2); residual standard deviation (RSD) and Akaike information criteria (AIC). The estimation of the parameters from models was performed by the weighted least squares method in Software R. All models evaluated were suitable to describe the growth curve in both sexes. In view of the evaluators used, the logistic model was the most suitable to describe the growth curves in withers height in both sexes for the race Mangalarga Marchador. A strong growth at first age was also observed. The males reached a greater adult height, but females did so sooner, because they presented higher estimates for the maturity index.(AU)

A genetic variant of NLRP1 gene is associated with asbestos body burden in patients with malignant pleural mesothelioma.

The presence of asbestos bodies (ABs) in lung parenchyma is considered a histopathologic hallmark of past exposure to asbestos fibers, of which there was a population of longer fibers. The mechanisms underlying AB formation are complex, involving inflammatory responses and iron (Fe) metabolism. Thus, the responsiveness to AB formation is variable, with some individuals appearing to be poor AB formers. The aim of this study was to disclose the possible role of genetic variants of genes encoding inflammasome and iron metabolism proteins in the ability to form ABs in a population of 81 individuals from North East Italy, who died after having developed malignant pleural mesothelioma (MPM). This study included 86 genetic variants distributed in 10 genes involved in Fe metabolism and 7 genetic variants in two genes encoding for inflammasome molecules. Genotypes/haplotypes were compared according to the number of lung ABs. Data showed that the NLRP1 rs12150220 missense variant (H155L) was significantly correlated with numbers of ABs in MPM patients. Specifically, a low number of ABs was detected in individuals carrying the NLRP1 rs12150220 A/T genotype. Our findings suggest that the NLRP1 inflammasome might contribute in the development of lung ABs. It is postulated that the NLRP1 missense variant may be considered as one of the possible host genetic factors contributing to individual variability in coating efficiency, which needs to be taken when assessing occupational exposure to asbestos.

Synergic effect of oral contraceptives, GSTP1 polymorphisms, and high-risk HPV infection in development of cervical lesions.

Human papillomavirus (HPV) infection is considered a risk factor for cervical cancer. Even if the high-risk HPV (HR-HPV) infection is necessary, environmental co-factors and genetic susceptibility also play an important role in cervical cancer development. In this study, a possible association of rs1695 GSTP1 polymorphisms, HR-HPV infection, and oral contraceptive use with cancer lesion development in women was investigated. The study population comprised 441 Brazilian women from the Northeast region including 98 HPV-infected women with high-grade squamous intraepithelial lesions, 77 HPV-infected women with low-grade squamous intraepithelial lesions, and 266 HPV-negative women with no lesion, used as a control. Our data did not show a significant association between the GSTP1 polymorphism A/G (rs1695) and any HPV-related cervical abnormalities. However, considering the use of oral contraceptives, the GSTP1 rs1695 polymorphism was associated with higher susceptibility to the development of cervical lesions in HR-HPV-infected women. Our study suggests a synergic effect of oral contraceptive use, GSTP1 polymorphisms, and HR-HPV infection in the development of cervical lesions. Together, these risk factors may induce neoplastic transformation of the cervical squamous epithelium, setting conditions for secondary genetic events leading to cervical cancer.

Validação do Nanolipe ® como método para determinar a digestibilidade aparente dos nutrientes pelos equinos / Validation of Nanolipe ® as method to assess the apparent digestibility of nutrients on horses

O NANOLIPE® é o indicador de digestibilidade LIPE® com incorporação de nano partículas que se misturam de forma mais homogênea e rápida na digesta, permitindo redução do período de adaptação e maiores taxas de recuperação daquele quando comparado com outros indicadores usados em equinos. Objetivou-se neste trabalho comparar a digestibilidade dos nutrientes de dieta em equinos obtida pelo método padrão (coleta total de fezes - CTF), estimada por dois indicadores internos (fibra em detergente ácido indigestível - FDAi; lignina Klason - LK) e por indicador externo NANOLIPE®, visando à validação deste último para uso na nutrição equina. Em delineamento de blocos ao acaso, oito éguas Mangalarga Marchador adultas (média de 380kg PV) foram usadas para avaliação dos tratamentos (CTF, FDAi, LK, NANOLIPE®). A dieta foi composta por 1,5% PV de feno de coast cross, 1,0% PV de concentrado comercial com 13% PB, dividido em dois tratos diários fornecidos às oito e às 17h, além de água e sal mineral à vontade. O experimento teve duração de 13 dias, sendo os oito iniciais para adaptação à dieta e ao manejo e os cinco finais para coleta de fezes. O NANOLIPE® foi fornecido no terceiro e quarto dias da coleta de fezes, sendo administrado uma vez por dia, por meio de cápsulas de 0,25g/animal/dia via oral. Houve diferença (P<0,05) entre os valores de produção fecal estimados pela FDAi (0,86kg MS) e LK (0,60kg MS) em comparação aos observados na CTF (2,16kg MS) e NANOLIPE® (2,17kg MS), com sub ou superestimação dos coeficientes de digestibilidade da MS, FDN, FDA, HEM, ED, MO e PB estimados pelos indicadores internos. O NANOLIPE® obteve alta taxa de recuperação (100,46%) e os coeficientes de digestibilidade de todos nutrientes foram semelhantes aos obtidos pela CTF. O indicador NANOLIPE® foi eficiente para estimativa da produção fecal e digestibilidade aparente dos nutrientes da dieta em equinos, quando fornecido por dois dias, sendo uma aplicação diária e com início da coleta de fezes, 24 horas após sua administração.(AU)

NANOLIPE® is the LIPE®digestibility indicator incorporating nano particles that blend more smoothly and quickly in digesta, allowing reduction of the induction period, and higher recovery rates that compared with other indicators used in horses. The objective of this work was to compare the digestibility of the diet of nutrients in horses obtained by standard method (total collection of feces - TCF) and estimated by two internal indicators ( Klason Lignin - KL and indigestible Acid Detergent Fiber.- iADF) ) and external indicator NANOLIPE®, aiming to validate the latter for use in equine nutrition. In a randomized block design, eight Mangalarga Marchador adult mares were used to evaluate treatments (CBC, iADF, LK, NANOLIPE®). The diet was composed of 1.5% PV hay Coast Cross, 1.0% PV of commercial concentrate, divided into two daily treatment.. The trial lasted 13 days, with 8 adaptation to the diet and the handling and 5 for the experimental procedures. In the first five days of the experimental period total feces was collected and in the 3th and 4th day the animals received NANOLIPE® administered once a day through capsules of 0.25 g / animal / day orally. Using the method of TFC as standart, the Klason Lignin and iADF proved inadequate (P<0,05) and NANOLIPE® was considered efficient (P>0,05) for estimating the digestibility of nutrients in the equine species. There were differences (P <0.05) between fecal production values estimated by iADF (0.86 kg DM) and LK (0.60 kg DM) compared to those observed in CTF (2.16 kg DM) and NANOLIPE® (2.17 kg DM) with under- or overestimation of the digestibility of DM, NDF, ADF, HEM, ED, OM and CP estimated by internal indicators. The NANOLIPE® got high recovery rate (100.46%) and the digestibility coefficients of all nutrients were similar to those obtained by the CTF. The NANOLIPE® indicator was efficient to estimate fecal output and apparent digestibility of dietary nutrients in horses when provided for two days, with a daily application and start collecting feces 24 hours after administration.(AU)

Reproductive biology of Haemulon plumierii in the south-western Atlantic Ocean's most extensive reefs: implications for fisheries management.

The reproductive biology of the white grunt Haemulon plumierii was studied from 360 individuals obtained from artisanal fisheries landings in the Abrolhos Bank, Brazil, between August 2010 and March 2012. The overall sex-ratio did not differ significantly from 1:1, although males predominated in larger size classes. ß-Binomial modelling of historical sex-ratio data indicated that the catch rate of females has increased in recent years. Females reached maturity at a smaller total length (LT ; 214 mm) than males (235 mm LT ) and the LT at which 50% of all individuals are mature (L50 ) was 220 mm, corresponding to 41·5% of the maximum recorded LT . Variation in the gonado-somatic index and in the relative frequency of reproductive stages indicates that reproduction occurs year round, with increased activity during the austral spring and summer. Fecundity was not size dependent. The reproductive parameters provided here can support management measures focussed on seasonal closures during spawning peaks (September to November and February to March) and minimum sizes (>L50 ) for the capture of this important artisanal fisheries resource in Abrolhos, the region with the largest and most biodiverse coralline reefs in the South Atlantic Ocean.

Association of interferon-induced helicase C domain (IFIH1) gene polymorphisms with systemic lupus erythematosus and a relevant updated meta-analysis.

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder presenting heterogeneous clinical manifestations. A number of genes involved in SLE susceptibility are related to the type I interferon (IFN) pathway. IFN mediates innate immune responses and its increased levels contribute to the breakdown of peripheral tolerance. Interferon-induced helicase C domain 1 (IFIH1) activates and modulates IFN responses through its caspase recruitment domain. In this study, we analyzed four IFIH1 single nucleotide polymorphisms (SNPs): rs6432714, rs10930046, rs1990760, and rs3747517, in 337 patients with SLE and 373 healthy individuals from southeast and northeast Brazil. Our results did not find an association between IFIH1 SNPs and SLE (P value >0.025 after Bonferroni's adjustment). However, meta-analysis of peer-reviewed articles from 2008 to 2015 and data from this study indicated an association between rs1990760 and SLE onset (P < 0.05). This is the first association analysis on IFIH1 polymorphisms and SLE susceptibility in Brazilian populations.

Detecting multiple DNA human profile from a mosquito blood meal.

Criminal traces commonly found at crime scenes may present mixtures from two or more individuals. The scene of the crime is important for the collection of various types of traces in order to find the perpetrator of the crime. Thus, we propose that hematophagous mosquitoes found at crime scenes can be used to perform genetic testing of human blood and aid in suspect investigation. The aim of the study was to obtain a single Aedes aegypti mosquito profile from a human DNA mixture containing genetic materials of four individuals. We also determined the effect of blood acquisition time by setting time intervals of 24, 48, and 72 h after the blood meal. STR loci and amelogenin were analyzed, and the results showed that human DNA profiles could be obtained from hematophagous mosquitos at 24 h following the blood meal. It is possible that hematophagous mosquitoes can be used as biological remains at the scene of the crime, and can be used to detect human DNA profiles of up to four individuals.

HLA-G genetic variants and hepatocellular carcinoma: a meta-analysis.

Human leukocyte antigen (HLA)-G is a key tolerogenic molecule mainly expressed in the placenta and is crucial for implantation of the embryo and immunological tolerance of the fetus during pregnancy. However, under pathological conditions, such as cancer or viral infections, HLA-G can be expressed in other tissues. The gene coding for HLA-G (HLA-G, chromosome 6p21.3) presents numerous polymorphisms, some of them influencing its expression. One of the most studied, is the 14 bp ins/del (rs371194629) situated at the 3'-UTR of the gene. The insertion is thought to stabilize HLA-G mRNA. Different studies have analyzed the role of rs371194629 in hepatic injury, with either hepatotropic virus infection (i.e., HBV or HCV) or hepatocellular carcinoma (also induced by viral infection). Results from these studies are heterogeneous, differing with ethnicity and population age, and the role of rs371194629 is unclear. For these reasons, we decided to perform a meta-analysis of these results, concluding that the 14-bp ins/del polymorphism does not significantly contribute to hepatic injury.

Mesophotic fishes of the Abrolhos Shelf, the largest reef ecosystem in the South Atlantic.

Fishes inhabiting rhodolith beds and reefs at mesophotic depths on the Abrolhos Shelf, which encompasses the largest and richest coral reef formation in the South Atlantic Ocean, were assessed through technical diving and remotely operated vehicles (ROVs). A total of 74 fish species were recorded, including at least one new species, one new record for the south-western Atlantic and six new records for the Abrolhos region. Overfishing, mining and port activities are already threatening many endangered and commercially important species recorded on the mesophotic reefs of Abrolhos Shelf, and the establishment of marine protected areas and off-reserve fisheries regulations are urgently needed.

Poultry slaughterhouse wastewater treatment plant for high quality effluent.

This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mg N-NH3 and phosphorus concentration of 1.34 ± 0.93 mg PO4(-3)/L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.

Hypothalamic stearoyl-CoA desaturase-2 (SCD2) controls whole-body energy expenditure.

BACKGROUND/OBJECTIVES: Stearoyl-CoA desaturase-2 (SCD2) is the main δ9 desaturase expressed in the central nervous system. Because of its potential involvement in controlling whole-body adiposity, we evaluated the expression and function of SCD2 in the hypothalami of mice. SUBJECTS/METHODS: Male mice of different strains were used in real-time PCR, immunoblot and metabolic experiments. In addition, antisense oligonucleotides and lentiviral vectors were used to reduce and increase the expression of SCD2 in the hypothalamus. RESULTS: The level of SCD2 in the hypothalamus is similar to other regions of the central nervous system and is ~10-fold higher than in any other region of the body. In the arcuate nucleus, SCD2 is expressed in proopiomelanocortin and neuropeptide-Y neurons. Upon high fat feeding, the level of hypothalamic SCD2 increases. Inhibition of hypothalamic SCD2 as accomplished by two distinct approaches, an antisense oligonucleotide or a short-hairpin RNA delivered by a lentivirus, resulted in reduced body mass gain mostly due to increased energy expenditure and increased spontaneous activity. Increasing hypothalamic SCD2 by a lentivirus approach resulted in no change in body mass and food intake. CONCLUSIONS: Thus, SCD2 is highly expressed in the hypothalami of rodents and its knockdown reduces body mass due to increased whole-body energy expenditure.

Physical mapping of 18S and 5S rDNA loci and histone H3 gene in grasshopper species of the subfamily Gomphocerinae (Acrididae).

In this study, fluorescence in situ hybridization (FISH) analysis was used to determine and compare the numbers and chromosomal locations of two multigene families (rDNA and histone H3) in four Neotropical species of gomphocerine grasshoppers. FISH using the 18S rDNA probe identified a single site on the S9 chromosome of Amblytropidia sp and Cauratettix borelli, a single site on chromosome M6 of Compsacris pulcher, and two sites (chromosomes L1 and L2) in Orphulella punctata. By contrast, FISH with a 5S rDNA probe identified dispersion of this sequence in the genomes of the four species, with evidence of intraspecific variations. Amblytropidia sp had six to eight FISH signals on autosomal chromosomes, while C. pulcher exhibited a signal only on the M5 bivalent. The histone H3 gene was less variable and was restricted to a single pair in all species. The conservation of the numbers and locations of 18S rDNA and H3 genes in conjunction with data from the literature was useful for evaluating karyotype evolution in this subfamily. The variation in the number and sizes of 5S rDNA sites indicates a process of recent dispersion that might have been mediated by transposition.