Mercury and selenium in oysters Saccostrea palmula and Crassostrea corteziensis from coastal lagoons of the southeastern Gulf of California: molar ratio and risk assessment on human health.

Total mercury (Hg) and selenium (Se) contents were determined in oysters Saccostrea palmula and Crassostrea corteziensis soft tissues from four coastal lagoons of the southeastern Gulf of California. The annual Hg mean concentrations for S. palmula (0.09 ± 0.04 µg g- 1, wet weight) and C. corteziensis (0.08 ± 0.04 µg g- 1) were similar (p ˃ 0.05) among the lagoons and did not exceed the limit established by the Norma Oficial Mexicana and World Health Organization (< 1.0 µg g- 1 Hg). On the other hand, the annual mean concentrations of Se for S. palmula (3.34 ± 0.96 µg g- 1) and C. corteziensis (2.79 ± 0.89 µg g- 1) were higher (p < 0.05) in El Colorado lagoon. The Se/Hg molar ratios were above 1; the positive selenium health benefit value index suggested that Se load in oysters could reduce the Hg potential toxic effect. The hazard quotient for Hg in both species was below 1. Therefore, the consumption of oysters does not represent a risk due to Hg ingestion.

Histopathological alterations in the gonads of wild white clams Dosinia ponderosa inhabiting a former copper mine locality in the Gulf of California.

OBJECTIVE: Prolonged exposure to heavy metals, such as Pb, Hg, or Cu, has multiple adverse effects on marine organisms at the cellular, physiological, and population levels. Bivalves' histopathology provides a sensitive biomarker of pollutant-induced stress and environmental health. Gonad tissue deterioration is of particular concern, as it affects the reproductive success of a species. This study aimed to examine the histopathological alterations caused by metal exposure in the gonad of the white clam Dosinia ponderosa. METHODS: Organisms were sampled from three locations in the Gulf of California: Santa Rosalia (SR), a former Cu mining town; San Lucas beach (SL), a nearby site influenced by pollution; and Escondida beach (EB), which served as a control site. Histological and histochemical stains were used, and the prevalence and intensity level of each alteration were calculated. RESULT: The prevalence of alterations was higher in the ovaries of SR clams (92% compared to 60% in SL clams and 32.7% in EB clams), during spawning (91.4% compared to 20% in SL clams and 4.7% in EB clams), and in winter (93.5% compared to 30% in SL clams and 17.4% in EB clams). CONCLUSION: These findings suggest a significant deterioration in the gonads of white clams from SR, probably linked to the chronic exposure to high concentrations of Cu and possibly other heavy metals; hence, the reproductive health of the clams is likely compromised.

Variable digestibility of captive northern greater galagos (Otolemur garnettii) fed experimental "frugivorous" and "invertebrate" diets.

Few studies have addressed the nutritional ecology of galagos. Observations of galagos in the wild reveal that they rely on fruits and invertebrates to varying degrees depending on their availability. We conducted a 6-week comparative dietary analysis of a colony of captive-housed northern greater galagos (Otolemur garnettii), which included five females and six males with known life histories. We compared two experimental diets. The first was fruit dominated and the second was invertebrate dominated. For each diet, we examined dietary intake and apparent dry matter digestibility over the course of 6 weeks. We found significant differences between the apparent digestibility of the diets, with the "invertebrate" diet being more digestible than the "frugivorous" diet. The lower apparent digestibility of the "frugivorous" diet was driven by the higher fiber contents of the fruits provided to the colony. However, variation in apparent digestibility of both diets was found among individual galagos. The experimental design used in this study may provide useful dietary data for the management of captive colonies of galagos and other strepsirrhine primates. This study may also be helpful for understanding the nutritional challenges faced by free-ranging galagos through time and across geographic space.

Digital mapping of the soil available water capacity: tool for the resilience of agricultural systems to climate change.

Soil available water capacity (AWC) is a key function for human survival and well-being. However, its direct measurement is laborious and spatial interpretation is complex. Digital soil mapping (DSM) techniques emerge as an alternative to spatial modeling of soil properties. DSM techniques commonly apply machine learning (ML) models, with a high level of complexity. In this context, we aimed to perform a digital mapping of soil AWC and interpret the results of the Random Forest (RF) algorithm and, in a case study, to show that digital AWC maps can support agricultural planning in response to the local effects of climate change. To do so, we divided this research into two approaches: In the first approach, we showed a DSM using 1857 sample points in a southeastern region of Brazil with laboratory-determined soil attributes, together with a pedotransfer function (PTF), remote sensing and DSM techniques. In the second approach, the constructed AWC digital soil map and weather station data were used to calculate climatological soil water balances for the periods between 1917-1946 and 1991-2020. The result showed the selection of covariates using Shapley values as a criterion contributed to the parsimony of the model, obtaining goodness-of-fit metrics of R2 0.72, RMSE 16.72 mm m-1, CCC 0.83, and Bias of 0.53 over the validation set. The highest contributing covariates for soil AWC prediction were the Landsat multitemporal images with bare soil pixels, mean diurnal, and annual temperature range. Under the current climate conditions, soil available water content (AW) increased during the dry period (April to August). May had the highest increase in AW (∼17 mm m-1) and decrease in September (∼14 mm m-1). The used methodology provides support for AWC modeling at 30 m resolution, as well as insight into the adaptation of crop growth periods to the effects of climate change.

The impact of urine collection method on canine urinary microbiota detection: a cross-sectional study.

BACKGROUND: The urinary tract harbors unique microbial communities that play important roles in urogenital health and disease. Dogs naturally suffer from several of the same urological disorders as humans (e.g., urinary tract infections, neoplasia, urolithiasis) and represent a valuable translational model for studying the role of urinary microbiota in various disease states. Urine collection technique represents a critical component of urinary microbiota research study design. However, the impact of collection method on the characterization of the canine urinary microbiota remains unknown. Therefore, the objective of this study was to determine whether urine collection technique alters the microbial populations detected in canine urine samples. Urine was collected from asymptomatic dogs by both cystocentesis and midstream voiding. Microbial DNA was isolated from each sample and submitted for amplicon sequencing of the V4 region of the bacterial 16 S rRNA gene, followed by analyses to compare microbial diversity and composition between urine collection techniques. RESULTS: Samples collected via midstream voiding exhibited significantly higher sequence read counts (P = .036) and observed richness (P = .0024) than cystocentesis urine. Bray Curtis and Unweighted UniFrac measures of beta diversity showed distinct differences in microbial composition by collection method (P = .0050, R2 = 0.06 and P = .010, R2 = 0.07, respectively). Seven taxa were identified as differentially abundant between groups. Pasteurellaceae, Haemophilus, Friedmanniella, two variants of Streptococcus, and Fusobacterium were over-represented in voided urine, while a greater abundance of Burkholderia-Caballeronia-Paraburkholderia characterized cystocentesis samples. Analyses were performed at five thresholds for minimum sequence depth and using three data normalization strategies to validate results; patterns of alpha and beta diversity remained consistent regardless of minimum read count requirements or normalization method. CONCLUSION: Microbial composition differs in canine urine samples collected via cystocentesis as compared to those collected via midstream voiding. Future researchers should select a single urine collection method based on the biological question of interest when designing canine urinary microbiota studies. Additionally, the authors suggest caution when interpreting results across studies that did not utilize identical urine collection methods.

Characterization of the urogenital microbiome in Miniature Schnauzers with and without calcium oxalate urolithiasis.

BACKGROUND: Calcium oxalate (CaOx) uroliths are common in dogs. Humans with CaOx urolithiasis exhibit alterations of the urinary and urogenital microbiomes that might mediate urolith formation. Detection of urogenital microbes associated with CaOx in dogs could inform disease pathophysiology. OBJECTIVE: To identify compositional differences in the urogenital microbiome of Miniature Schnauzers with and without CaOx uroliths. ANIMALS: Nineteen midstream, voided urine samples from Miniature Schnauzers with (n = 9) and without (n = 10) a history of CaOx urolithiasis. METHODS: Analytical cross-sectional study. Microbial DNA was extracted from previously frozen urine samples and sequenced for the bacterial 16S rRNA V3-V4 hypervariable regions. Diversity and composition of microbial populations were compared between urolith formers and controls. RESULTS: Alpha and beta diversity measures were similar between groups. Five individual bacterial taxa differed in abundance (indicator values >0.5 and P < .05): Acinetobacter, 2 Geobacillus variants, and Hydrogenophaga were overrepresented in the urine of urolith formers, and Sphingopyxis was overrepresented in controls. Two distinct subtypes of urine microbial composition were observed based on beta diversity measures, independent of urolith status, and other clinical variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Although we did not detect a difference in the overall urogenital microbial composition between groups, observed differences in individual bacterial taxa might be clinically relevant. For example, Acinetobacter was overrepresented in urolith formers and is associated with CaOx urolithiasis in humans. Two unique clusters of the microbiome were identified, independent of urolith status, which may represent distinct urotypes present in Miniature Schnauzers.

Desove y desarrollo intracapsular del caracol marino Hexaplexnigritus (Neogastropoda: Muricidae) en laboratorio / Spawning and intracapsular development of the marine snail Hexaplex nigritus (Neograstropoda: Muricidae) in the laboratory

Introducción: El caracol marino Hexaplex nigritus es un murícido fuertemente explotado en el Golfo de California para consumo y artesanías. Cuando se reproducen, los adultos se agregan en forma de arrecifes artificiales facilitando su identificación y extracción, lo cual, ha mermado su población en dicha zona. Objetivo: Investigar el desove y desarrollo intracapsular y larvario de esta especie como herramientas para su producción en cautiverio con fines de repoblamiento. Métodos: Se recolectaron 18 progenitores que fueron mantenidos en un sistema cerrado con parámetros y alimentación controladas durante abril 2017 hasta septiembre 2018. Se registró: crecimiento de progenitores, desove de masas ovígeras, cantidad de cápsulas y número de embriones y larvas dentro de las cápsulas. La temperatura de incubación fue de 28.2 ± 1.5 °C. Las principales estructuras morfológicas de embriones y larvas fueron documentadas conforme su desarrollo. Resultados: El desarrollo embrionario intracapsular y de la larva velígera hasta su asentamiento tuvieron una duración de 14-15 y 31-32 días, respectivamente. Cada hembra de 80-88 mm de longitud produjo alrededor de 4 masas ovígeras, 627 cápsulas y 663 993 larvas velígeras extracapsulares por año. Conclusiones: La fácil adaptación y el potencial reproductivo mostrado por H. nigritus en laboratorio se presentan como estrategias promisorias para su repoblación y conservación.

Introduction: The marine snail Hexaplex nigritus is a heavily exploited muricid in the Gulf of California for consumption and handcrafts. When they reproduce, adults aggregated in the form of artificial reefs facilitating their identification and extraction, situation that has reduced their population in that area. Objective: In order to investigate the spawning and intracapsular and larval development of this species as tools for its production in captivity for repopulation purposes. Methods: Eighteen brooders were collected and kept in a closed system with controlled parameters and feeding from April 2017 to September 2018. Growth of parents, spawning of ovigerous masses, number of capsules, and number of embryos and larvae within the capsules, were registered. The main morphological structures of embryos and larvae were documented according to their development. Results: Intracapsular embryonic development and veliger larva until its establishment lasted 14-15 and 31-32 days, respectively. Each 80-88 mm length female produced around 4 ovigerous masses, 627 capsules and 663 993 extracapsular veliger larvae per year. Conclusions: Easy adaptation and reproductive potential shown by H. nigritus in the laboratory are presented as promising strategies for its repopulation and conservation.

Association of Flavonifractor plautii, a Flavonoid-Degrading Bacterium, with the Gut Microbiome of Colorectal Cancer Patients in India.

Recently, dysbiosis in the human gut microbiome and shifts in the relative abundances of several bacterial species have been recognized as important factors in colorectal cancer (CRC). However, these studies have been carried out mainly in developed countries where CRC has a high incidence, and it is unclear whether the host-microbiome relationships deduced from these studies can be generalized to the global population. To test if the documented associations between the microbiome and CRC are conserved in a distinct context, we performed metagenomic and metabolomic association studies on fecal samples from 30 CRC patients and 30 healthy controls from two different locations in India, followed by a comparison of CRC data available from other populations. We confirmed the association of Bacteroides and other bacterial taxa with CRC that have been previously reported in other studies. However, the association of CRC with Flavonifractor plautii in Indian patients emerged as a novel finding. The plausible role of F. plautii appears to be linked with the degradation of beneficial anticarcinogenic flavonoids, which was also found to be significantly correlated with the enzymes and modules involved in flavonoid degradation within Indian CRC samples. Thus, we hypothesize that the degradation of beneficial flavonoids might be playing a role in cancer progression within this Indian cohort. We also identified 20 potential microbial taxonomic markers and 33 potential microbial gene markers that discriminate the Indian CRC from healthy microbiomes with high accuracy based on machine learning approaches.IMPORTANCE This study provides novel insights on the CRC-associated microbiome of a unique cohort in India, reveals the potential role of a new bacterium in CRC, and identifies cohort-specific biomarkers, which can potentially be used in noninvasive diagnosis of CRC. The study gains additional significance, as India is among the countries with a very low incidence of CRC, and the diet and lifestyle in India have been associated with a distinct gut microbiome in healthy Indians compared to other global populations. Thus, in this study, we hypothesize a unique relationship between CRC and the gut microbiome in an Indian population.

Strain Level Streptococcus Colonization Patterns during the First Year of Life.

Pneumococcal pneumonia has decreased significantly since the implementation of the pneumococcal conjugate vaccine (PCV), nevertheless, in many developing countries pneumonia mortality in infants remains high. We have undertaken a study of the nasopharyngeal (NP) microbiome during the first year of life in infants from The Philippines and South Africa. The study entailed the determination of the Streptococcus sp. carriage using a lytA qPCR assay, whole metagenomic sequencing, and in silico serotyping of Streptococcus pneumoniae, as well as 16S rRNA amplicon based community profiling. The lytA carriage in both populations increased with infant age and lytA+ samples ranged from 24 to 85% of the samples at each sampling time point. We next developed informatic tools for determining Streptococcus community composition and pneumococcal serotype from metagenomic sequences derived from a subset of longitudinal lytA-positive Streptococcus enrichment cultures from The Philippines (n = 26 infants, 50% vaccinated) and South African (n = 7 infants, 100% vaccinated). NP samples from infants were passaged in enrichment media, and metagenomic DNA was purified and sequenced. In silico capsular serotyping of these 51 metagenomic assemblies assigned known serotypes in 28 samples, and the co-occurrence of serotypes in 5 samples. Eighteen samples were not typeable using known serotypes but did encode for capsule biosynthetic cluster genes similar to non-encapsulated reference sequences. In addition, we performed metagenomic assembly and 16S rRNA amplicon profiling to understand co-colonization dynamics of Streptococcus sp. and other NP genera, revealing the presence of multiple Streptococcus species as well as potential respiratory pathogens in healthy infants. A range of virulence and drug resistant elements were identified as circulating in the NP microbiomes of these infants. This study revealed the frequent co-occurrence of multiple S. pneumoniae strains along with Streptococcus sp. and other potential pathogens such as S. aureus in the NP microbiome of these infants. In addition, the in silico serotype analysis proved powerful in determining the serotypes in S. pneumoniae carriage, and may lead to developing better targeted vaccines to prevent invasive pneumococcal disease (IPD) in these countries. These findings suggest that NP colonization by S. pneumoniae during the first years of life is a dynamic process involving multiple serotypes and species.

Reproduction of Megapitaria squalida (Bivalvia: Veneridae) in the Southeast Gulf of California, Mexico / Reproducción de la almeja callista Megapitaria squalida (Bivalvia: Veneridae) en el sureste del Golfo de California, México

AbstractBivalves reproductive cycle varies according to the particular environmental conditions where they are found, and these reproductive details represent basic information for their capture, management and conservation strategies. With this objective, the reproductive cycle of the clam Megapitaria squalida, inhabiting the Southeast of the Gulf of California (Altata Bay, Sinaloa, Mexico), was studied using histology and changes in the number and size of oocytes, from June 2013 to June 2014. Histological analysis of the gonads showed spawning activity throughout the year, with two peaks. The first was registered in October and it was accompanied by the highest decrease of weight; the second was in February with the highest percentage of spawning population; besides, a resting period was observed in December. The sex-ratio (female:male) of the clam population was 1.08:1 (χ2 = 5.72, d.f. = 1, P < 0.05). Mean oocyte size and number were different (P < 0.05) among all sampling months and fluctuated from 34.6 ± 5.8 µm in June 2014, to 41.9 ± 6.8 µm in February 2014, and from 443.8 ± 424.5 in February 2014, to 1 214.4 ± 267.6 counted in April, respectively. With these results we suggest a protection season from October to November, when the most intense release of gametes occur in this population. Rev. Biol. Trop. 65 (3): 881-889. Epub 2017 September 01.

ResumenEl ciclo reproductivo de los bivalvos varía de acuerdo a las condiciones ambientales de cada lugar, y representa información importante para su conservación. Se estudió el ciclo reproductivo de la almeja Megapitaria squalida utilizando cortes histológicos de la gónada y cambios en el número y tamaño de los oocitos, en el sur del Golfo de California (Bahía Altata, Sinaloa, México), desde junio 2013 a junio 2014. El análisis histológico de las gónadas, mostró eventos de desove todo el año con dos picos: el primero fue registrado en octubre acompañado con un fuerte decremento en peso de los animales; el segundo en febrero caracterizado por un alto porcentaje de desove en la población. Se observó un periodo de reposo en diciembre. La proporción sexual (hembras:machos) de la población de almejas fue 1.08:1 (χ2 = 5.72, g.l. = 1, P < 0.05). El número y tamaño promedio de los oocitos mostró diferencias (P < 0.05) entre los muestreos mensuales, y fluctuaron de 34.6 ± 5.8 µm en junio 2014 a 41.9 ± 6.8 µm en febrero 2014, y de 443.8 ± 424.5 en febrero 2014, a 1 214.4 ± 267.6 en abril 2014. Se propone una temporada de veda desde octubre a noviembre, ya que en estos meses la liberación de gametos por la población fue más intensa.

Low incidence of spontaneous type 1 diabetes in non-obese diabetic mice raised on gluten-free diets is associated with changes in the intestinal microbiome.

Human and animal studies strongly suggest that dietary gluten could play a causal role in the etiopathogenesis of type 1 diabetes (T1D). However, the mechanisms have not been elucidated. Recent reports indicate that the intestinal microbiome has a major influence on the incidence of T1D. Since diet is known to shape the composition of the intestinal microbiome, we investigated using non-obese diabetic (NOD) mice whether changes in the intestinal microbiome could be attributed to the pro- and anti-diabetogenic effects of gluten-containing and gluten-free diets, respectively. NOD mice were raised on gluten-containing chows (GCC) or gluten-free chows (GFC). The incidence of diabetes was determined by monitoring blood glucose levels biweekly using a glucometer. Intestinal microbiome composition was analyzed by sequencing 16S rRNA amplicons derived from fecal samples. First of all, GCC-fed NOD mice had the expected high incidence of hyperglycemia whereas NOD mice fed with a GFC had significantly reduced incidence of hyperglycemia. Secondly, when the fecal microbiomes were compared, Bifidobacterium, Tannerella, and Barnesiella species were increased (p = 0.03, 0.02, and 0.02, respectively) in the microbiome of GCC mice, where as Akkermansia species was increased (p = 0.02) in the intestinal microbiomes of NOD mice fed GFC. Thirdly, both of the gluten-free chows that were evaluated, either egg white based (EW-GFC) or casein based (C-GFC), significantly reduced the incidence of hyperglycemia. Interestingly, the gut microbiome from EW-GFC mice was similar to C-GFC mice. Finally, adding back gluten to the gluten-free diet reversed its anti-diabetogenic effect, reduced Akkermansia species and increased Bifidobacterium, Tannerella, and Barnesiella suggesting that the presence of gluten is directly responsible for the pro-diabetogenic effects of diets and it determines the gut microflora. Our novel study thus suggests that dietary gluten could modulate the incidence of T1D by changing the gut microbiome.