Gene functions of the Ambystoma altamirani skin microbiome vary across space and time but potential antifungal genes are widespread and prevalent.

Amphibian skin microbiomes can play a critical role in host survival against emerging diseases by protecting their host against pathogens. While a plethora of biotic and abiotic factors have been shown to influence the taxonomic diversity of amphibian skin microbiomes it remains unclear whether functional genomic diversity varies in response to temporal and environmental factors. Here we applied a metagenomic approach to evaluate whether seasonality, distinct elevations/sites, and pathogen presence influenced the functional genomic diversity of the A. altamirani skin microbiome. We obtained a gene catalogue of 92 107 nonredundant annotated genes and a set of 50 unique metagenome assembled genomes (MAGs). Our analysis showed that genes linked to general and potential antifungal traits significantly differed across seasons and sampling locations at different elevations. Moreover, we found that the functional genomic diversity of A. altamirani skin microbiome differed between B. dendrobatidis infected and not infected axolotls only during winter, suggesting an interaction between seasonality and pathogen infection. In addition, we identified the presence of genes and biosynthetic gene clusters (BGCs) linked to potential antifungal functions such as biofilm formation, quorum sensing, secretion systems, secondary metabolite biosynthesis, and chitin degradation. Interestingly genes linked to these potential antifungal traits were mainly identified in Burkholderiales and Chitinophagales MAGs. Overall, our results identified functional traits linked to potential antifungal functions in the A. altamirani skin microbiome regardless of variation in the functional diversity across seasons, elevations/sites, and pathogen presence. Our findings suggest that potential antifungal traits found in Burkholderiales and Chitinophagales taxa could be related to the capacity of A. altamirani to survive in the presence of Bd, although further experimental analyses are required to test this hypothesis.

Characterization of Beta-Lactam Resistome of Escherichia coli Causing Nosocomial Infections.

Nosocomial infections caused by Escherichia coli pose significant therapeutic challenges due to the high expression of genes encoding antimicrobial drug resistance. In this study, we investigated the conformation of the beta-lactam resistome responsible for the specific pattern of resistance against beta-lactam antibiotics. A total of 218 Escherichia coli strains were isolated from in-hospital patients diagnosed with nosocomial infections, obtained from various sources such as urine (n = 49, 22.48%), vaginal discharge (n = 46, 21.10%), catheter tips (n = 14, 6.42%), blood (n = 13, 5.96%), feces (n = 12, 5.50%), sputum (n = 11, 5.05%), biopsies (n = 8, 3.67%), cerebrospinal fluid (n = 2, 0.92%) and other unspecified discharges (n = 63, 28.90%). To characterize the beta-lactam resistome, all strains were subjected to antibiotic dilution tests and grown in beta-lactam antibiotics supplemented with Luria culture medium. Subsequently, multiplex PCR and next-generation sequencing were conducted. The results show a multi-drug-resistance phenotype, particularly against beta-lactam drugs. The primary determinant of this resistance was the expression of the blaTEM gene family, with 209 positive strains (95.87%) expressing it as a single gene (n = 47, 21.6%) or in combination with other genes. Common combinations included blaTEM + blaCTX (n = 42, 19.3%), blaTEM + blaCTX + blaSHV (n = 13, 6%) and blaTEM + blaCTX + blaBIL (n = 12, 5.5%), among others. The beta-lactam resistome of nosocomial Escherichia coli strains isolated from inpatients at the "October first" Regional Hospital of ISSSTE was predominantly composed of members of the blaTEM gene family, expressed in various configurations along with different members of other beta-lactamase gene families.

The skin microbiota of the axolotl Ambystoma altamirani is highly influenced by metamorphosis and seasonality but not by pathogen infection.

BACKGROUND: Microbiomes have been increasingly recognized as major contributors to host health and survival. In amphibians, bacterial members of the skin microbiota protect their hosts by inhibiting the growth of the fungal pathogen Batrachochytrium dendrobatidis (Bd). Even though several studies describe the influence of biotic and abiotic factors over the skin microbiota, it remains unclear how these symbiotic bacterial communities vary across time and development. This is particularly relevant for species that undergo metamorphosis as it has been shown that host physiology and ecology drastically influence diversity of the skin microbiome. RESULTS: We found that the skin bacterial communities of the axolotl A. altamirani are largely influenced by the metamorphic status of the host and by seasonal variation of abiotic factors such as temperature, pH, dissolved oxygen and conductivity. Despite high Bd prevalence in these samples, the bacterial diversity of the skin microbiota did not differ between infected and non-infected axolotls, although relative abundance of particular bacteria were correlated with Bd infection intensity. CONCLUSIONS: Our work shows that metamorphosis is a crucial process that shapes skin bacterial communities and that axolotls under different developmental stages respond differently to environmental seasonal variations. Moreover, this study greatly contributes to a better understanding of the factors that shape amphibian skin microbiota, especially in a largely underexplored group like axolotls (Mexican Ambystoma species).

The fungal pathogen Batrachochytrium salamandrivorans is not detected in wild and captive amphibians from Mexico.

The recent emergence of the pathogen Batrachochytrium salamandrivorans (Bsal) is associated with rapid population declines of salamanders in Europe and its arrival to new areas could cause dramatic negative effects on other amphibian populations and species. Amphibian species, present in areas with high amphibian diversity such as Mexico, could be highly threatened due to the arrival of Bsal, particularly salamander species which are more vulnerable to chytridiomycosis caused by this pathogen. Thus, immediate surveillance is needed as a strategy to efficiently contend with this emerging infectious disease. In this study, we analyzed 490 wild and captive amphibians from 48 species across 76 sites in the North, Central, and South of Mexico to evaluate the presence of Bsal. Amphibians were sampled in sites with variable degrees of amphibian richness and suitability for Bsal according to previous studies. From the 76 sampling sites, 10 of them were located in areas with high amphibian richness and potential moderate to high Bsal habitat suitability. We did not detect Bsal in any of the samples, and no signs of the disease were observed in any individual at the time of sampling. Our results suggest that Bsal has not yet arrived at the sampled sites or could be at low prevalence within populations with low occurrence probability. This is the first study that evaluates the presence of Bsal in different regions and amphibian species in Mexico, which is the second most diverse country in salamander species in the world. We highlight the risk and the importance of continuing surveillance of Bsal in Mexico and discuss control strategies to avoid the introduction and spread of Bsal in the country.

Consumer Preferences and Sensory Profile Related to the Physico-Chemical Properties and Texture of Different Maize Tortillas Types.

Maize tortilla is a basic food in Mexico, and, lately, the food industry has tried to make the manufacturing process easier by using instant flours and specialized machines. The purpose of this study was to investigate consumers' behaviors related to tortillas and to evaluate the sensory, textural, and physico-chemical parameters of tortillas from the Tlazala region, Mexico. The sensory profile revealed that the artisanal ones had better parameters in terms of smell, taste, and appearance compared to the others. These results are consistent with consumers' preferences for tortillas made of maize grain instead of industrial corn flour. The sensory parameters and the physico-chemical and texture profile parameters varied with the maize type and manufacturing process. Our findings showed that the artisanal hand-made ones were more nutritious, followed by those mechanically made using maize grain, and finally by those mechanically made from industrialized corn flour. The results of this study may help processors to better understand the parameters of their products and people's preferences.

Leveraging Citizen Science for Healthier Food Environments: A Pilot Study to Evaluate Corner Stores in Camden, New Jersey.

Over the last 6 years, a coordinated "healthy corner store" network has helped an increasing number of local storeowners stock healthy, affordable foods in Camden, New Jersey, a city with high rates of poverty and unemployment, and where most residents have little or no access to large food retailers. The initiative's funders and stakeholders wanted to directly engage Camden residents in evaluating this effort to increase healthy food access. In a departure from traditional survey- or focus group-based evaluations, we used an evidence-based community-engaged citizen science research model (called Our Voice) that has been deployed in a variety of neighborhood settings to assess how different features of the built environment both affect community health and wellbeing, and empower participants to create change. Employing the Our Voice model, participants documented neighborhood features in and around Camden corner stores through geo-located photos and audio narratives. Eight adult participants who lived and/or worked in a predefined neighborhood of Camden were recruited by convenience sample and visited two corner stores participating in the healthy corner store initiative (one highly-engaged in the initiative and the other less-engaged), as well as an optional third corner store of their choosing. Facilitators then helped participants use their collected data (in total, 134 images and 96 audio recordings) to identify and prioritize issues as a group, and brainstorm and advocate for potential solutions. Three priority themes were selected by participants from the full theme list (n = 9) based on perceived importance and feasibility: healthy product selection and display, store environment, and store outdoor appearance and cleanliness. Participants devised and presented a set of action steps to community leaders, and stakeholders have begun to incorporate these ideas into plans for the future of the healthy corner store network. Key elements of healthy corner stores were identified as positive, and other priorities, such as improvements to safety, exterior facades, and physical accessibility, may find common ground with other community development initiatives in Camden. Ultimately, this pilot study demonstrated the potential of citizen science to provide a systematic and data-driven process for public health stakeholders to authentically engage community residents in program evaluation.

Measurement of single breath-hold carbon monoxide diffusing capacity in healthy infants and toddlers.

We describe a method for measuring carbon monoxide diffusing capacity (DL(CO)) and alveolar volume (V(A)) in sleeping infants, using a single 4-sec breath-hold technique. The breath-hold maneuver is obtained by inducing a respiratory pause of the respiratory system. Several inflations of the respiratory system with room air to a lung volume with an airway pressure of 30 cmH2O (V30) inhibit inspiratory effort. The respiratory system is then inflated with a test gas containing helium and a stable isotope of carbon monoxide (C18O), and a respiratory pause is maintained for 4 sec and followed by passive expiration to functional residual capacity. Concentrations of helium and C18O are continuously measured with a mass spectrometer. Twelve healthy infants between 6-22 months of age were evaluated. For 9 of 12 subjects, duplicate measurements of alveolar volume at 30 cmH2O (V(A30)) and DL(CO) were within 10%, which are the recommendations for older children and adults. Among these 9 subjects, values of V(A30) and DL(CO) increased with increasing body length (r2 = 0.82 and 0.79, respectively). The remaining 3 subjects had two values within 10-15%. Measurement of V(A) and DL(CO) with the single breath-hold technique at an elevated lung volume offers the potential to assess growth and development of the lung parenchyma early in life.

High-resolution computed tomography imaging of airway disease in infants with cystic fibrosis.

RATIONALE: The development of early lung disease in patients with cystic fibrosis (CF) remains poorly defined. OBJECTIVE: Determine whether asymptomatic infants with CF have evidence for changes in airway structure when assessed by high-resolution computed tomography, and whether airway structure correlates with airway function in this age group. METHODS: Thirteen infants with CF (8-33 mo) and 13 control infants (7-25 mo) were evaluated. Airway wall and lumen areas were measured from three 1-mm-thick cross-sectional images obtained from upper, middle, and lower lobes during a respiratory pause with the lungs inflated to an airway pressure of 20 cm H2O. Lung tissue density was measured from images obtained during a respiratory pause at FRC. Forced expiratory flows were measured by the rapid thoracic compression technique in 11 infants with CF. RESULTS: Airway wall area increased more per unit increase in airway size, whereas airway lumen area increased less per unit increase in airway size in the CF than in the control group. Among infants with CF, a greater ratio of wall to lumen area correlated with lower airway function. In addition, lung density at relaxed (passive) FRC was lower for infants with CF than for control infants (0.38 vs. 0.43 g/ml; p < 0.02). CONCLUSIONS: Our results indicate that infants with CF have thickened airway walls, narrowed airway lumens, and air trapping, when assessed by high-resolution computed tomography, and measurements of airway structure correlated with airway function.

Parental smoking and airway reactivity in healthy infants.

Parental tobacco smoking is associated with lower airway function and an increased incidence of wheezy respiratory illnesses in infants. We evaluated in 76 healthy infants whether exposure to parental tobacco smoking was associated with airway hyperreactivity, which could contribute to lower airway function and the increased wheezy illnesses. Airway function was measured using the raised-volume rapid thoracic compression technique, and airway reactivity was assessed by methacholine challenge (0.015-10 mg/ml), which was stopped for a more than 30% decrease in forced expiratory flow (FEF)(75) or the final dose with a less than 30% decrease. Parental tobacco smoking was associated with lower baseline airway function (FEF(50), 600 vs. 676 ml/second, p < 0.04; FEF(25-75), 531 vs. 597 ml/second, p < 0.05). Infants exposed to tobacco smoking were approximately half as likely to develop a more than 30% decline in FEF(75) at any given methacholine dose (hazard ratio = 0.4, p = 0.001). In addition, a history of asthma in an extended family member increased the likelihood that an infant would develop a more than 30% decline in FEF(75) (hazard ratio = 1.7, p = 0.04). We conclude that exposure to parental smoking is associated with lower airway function but not increased airway reactivity; however, family history of asthma is associated with heightened airway reactivity.

[11C]Choline as a PET biomarker for assessment of prostate cancer tumor models.

[(11)C]Choline has been evaluated as a positron emission tomography (PET) biomarker for assessment of established human prostate cancer tumor models. [(11)C]Choline was prepared by the reaction of [(11)C]methyl triflate with 2-dimethylaminoethanol (DMAE) and isolated and purified by solid-phase extraction (SPE) method in 60-85% yield based on [(11)C]CO(2), 15-20 min overall synthesis time from end of bombardment (EOB), 95-99% radiochemical purity and specific activity >0.8 Ci/micromol at end of synthesis (EOS). The biodistribution of [(11)C]choline was determined at 30 min post iv injection in prostate cancer tumor models C4-2, PC-3, CWR22rv, and LNCaP tumor-bearing athymic mice. The results showed the accumulation of [(11)C]choline in these tumors was 1.0% dose/g in C4-2 mouse, 0.4% dose/g in PC-3 mice, 3.2% dose/g in CWR22rv mice, and 1.4% dose/g in LNCaP mice; the ratios of tumor/muscle (T/M) and tumor/blood (T/B) were 2.3 (T/M, C4-2), 1.4 (T/M, PC-3), 2.5 (T/M, CWR22rv), 1.2 (T/M, LNCaP) and 2.6 (T/B, C4-2), 2.6 (T/B, PC-3), 7.8 (T/B, CWR22rv), 3.2 (T/B, LNCaP), respectively. The micro-PET imaging of [(11)C]choline in prostate cancer tumor models was acquired from a C4-2, PC-3, CWR22rv, or LNCaP implanted mouse at 30 min post iv injection of 1 mCi of the tracer using a dedicated high resolution (<3 mm full-width at half-maximum) small FOV (field-of-view) PET imaging system, IndyPET-II scanner, developed in our laboratory, which showed the accumulation of [(11)C]choline in C4-2, PC-3, CWR22rv, or LNCaP tumor implanted in a nude athymic mouse. The initial dynamic micro-PET imaging data indicated the average T/M ratios were approximately 3.0 (C4-2), 2.1 (PC-3), 3.5 (CWR22rv), and 3.3 (LNCaP), respectively, which showed the tumor accumulation of [(11)C]choline in all four tumor models is high. These results suggest that there are significant differences in [(11)C]choline accumulation between these different tumor types, and these differences might offer some useful measure of tumor biological process.

Synthesis, biodistribution and micro-PET imaging of radiolabeled antimitotic agent T138067 analogues.

Radiolabeled antimitotic agents [11C]T138067 and [18F]T138067 have been synthesized for evaluation as new potential positron emission tomography (PET) biomarkers for cancer imaging. In vivo biodistribution and micro-PET imaging of [11C]T138067 were performed in breast cancer animal models MCF-7 transfected with IL-1alpha implanted athymic mice and MDA-MB-435 implanted athymic mice. The results suggest that the uptakes of [11C]T138067 in both MCF-7 transfected with IL-1alpha tumor and MDA-MB-435 tumor are non-specific binding.

Comparative studies of potential cancer biomarkers carbon-11 labeled MMP inhibitors (S)-2-(4'-[11C]methoxybiphenyl-4-sulfonylamino)-3-methylbutyric acid and N-hydroxy-(R)-2-[[(4'-[11C]methoxyphenyl)sulfonyl]benzylamino]-3-methylbutanamide.

(S)-2-(4'-[11C]methoxybiphenyl-4-sulfonylamino)-3-methylbutyric acid ([11C]MSMA) and N-hydroxy-(R)-2-[[(4'-[11C]methoxyphenyl)sulfonyl]benzylamino]-3-methylbutanamide ([11C]CGS 25966), carbon-11 labeled matrix metalloproteinase (MMP) inhibitors, have been synthesized for evaluation as new potential positron emission tomography (PET) cancer biomarkers. [11C]MSMA was prepared by appropriate precursor (S)-2-(4'-hydroxybiphenyl-4-sulfonylamino)-3-methylbutyric acid tert-butyl ester, which was synthesized in eight steps from amino acid (L)-valine in 39.4% chemical yield. This precursor was labeled by [11C]methyl triflate through O-[11C]methylation method at the hydroxyl position of biphenol under basic conditions, followed by a quick acid hydrolysis and isolated by solid-phase extraction (SPE) purification to produce pure target compound [11C]MSMA in 35-55% radiochemical yield, based on 11CO2, decay corrected to end of bombardment (EOB), and 20-25 min synthesis time. [11C]CGS 25966 was prepared in our previous work starting from amino acid (D)-valine. The biodistribution of [11C]MSMA and [11C]CGS 25966 were determined at 45 min post iv injection in breast cancer animal models MCF-7's transfected with IL-1alpha implanted athymic mice and MDA-MB-435 implanted athymic mice. The results showed the uptakes of [11C]MSMA and [11C]CGS 25966 in these tumors were 0.95 and 0.42%dose/g in MCF-7's transfected with IL-1alpha implanted mice, 0.98 and 1.53%dose/g in MDA-MB-435 implanted mice, respectively; the ratios of tumor/muscle (T/M) and tumor/blood (T/B) were 1.21 and 1.09 (T/M, MCF-7's), 0.99 and 0.84 (T/B, MCF-7's), 1.38 and 1.27 (T/M, MDA-MB-435), 1.27 and 1.95 (T/B, MDA-MB-435), respectively. The micro-PET images of [11C]MSMA and [11C]CGS 25966 in both breast cancer athymic mice were acquired for 15 min from a MCF-7's transfected with IL-1alpha and/or MDA-MB-435 implanted mouse at 45 min post iv injection of 1 mCi of the tracer using a dedicated high resolution (<3 mm full-width at half-maximum) small FOV (field-of-view) PET imaging system, Indy-PET II scanner, developed in our laboratory, which showed both tumors were invisible with both tracers. The results were compared. From our results, we concluded that both [11C]MSMA and [11C]CGS 25966 might be unsuitable as PET tracers for cancer imaging.

Synthesis, biodistribution and micro-PET imaging of a potential cancer biomarker carbon-11 labeled MMP inhibitor (2R)-2-[[4-(6-fluorohex-1-ynyl)phenyl]sulfonylamino]-3-methylbutyric acid [11C]methyl ester.

(2R)-2-[[4-(6-fluorohex-1-ynyl)phenyl]sulfonylamino]-3-methylbutyric acid [(11)C]methyl ester ([(11)C]FMAME), a novel carbon-11 labeled matrix metalloproteinase (MMP) inhibitor, has been synthesized for evaluation as new potential positron emission tomography (PET) cancer biomarker. [(11)C]FMAME was prepared by appropriate precursor (2R)-2-[[4-(6-fluorohex-1-ynyl)phenyl]sulfonylamino]-3-methylbutyric acid (FMA), which was synthesized in six steps from (D)-valine in 71% chemical yield. This acid precursor was labeled by [(11)C]methyl triflate through O-[(11)C]methylation method under basic conditions and isolated by solid-phase extraction (SPE) purification to produce pure target compound in 40-55% radiochemical yield, based on (11)CO(2), decay corrected to end of bombardment, and 15-20 min synthesis time. The biodistribution of [(11)C]FMAME was determined at 30 min post IV injection in breast cancer animal models MCF-7 transfected with IL-1 alpha implanted athymic mice and MDA-MB-435 implanted athymic mice. The results showed the uptakes of [(11)C]FMAME in these tumors were 1.13% dose/g in MCF-7 transfected with IL-1 alpha implanted mice and 1.37% dose/g in MDA-MB-435 implanted mice, respectively; the ratios of tumor/muscle (T/M) and tumor/blood (T/B) were 1.05 +/- 0.29 (T/M, MCF-7's), 0.77 +/- 0.20 (T/B, MCF-7's) and 0.99 +/- 0.35 (T/M, MDA-MB-435), 1.44 +/- 0.69 (T/B, MDA-MB-435), respectively. Pretreatment of MCF-7 transfected with IL-1 alpha tumor-bearing mice with MMP inhibitor FMA had no effect on [(11)C]FMAME biodistribution. Likewise, pretreatment of MDA-MB-435 tumor-bearing mice with FMA also showed no effect on [(11)C]FMAME biodistribution. The micro-PET images were acquired for 15 min from a MCF-7 transfected with IL-1 alpha tumor-bearing mouse or a MDA-MB-435 tumor-bearing mouse at 30 min post IV injection of 1 mCi of [(11)C]FMAME using a dedicated high resolution (<3 mm full-width at half-maximum) PET imaging system (Indy-PET II scanner). The initial dynamic micro-PET images of [(11)C]FMAME in a MCF-7 transfected with IL-1 alpha tumor-bearing mouse during different time periods of 0-15, 15-30, 30-45 and 45-60 min were performed by Indy-PET II. The PET images clearly showed both tumors were visible with [(11)C]FMAME. These results suggest that the localization of [(11)C]FMAME in the tumor is mediated by non-specific processes, and the visualization of [(11)C]FMAME on the tumor using the Indy-PET II scanner is related to non-specific binding.

Synthesis and preliminary biological evaluation of MMP inhibitor radiotracers [11C]methyl-halo-CGS 27023A analogs, new potential PET breast cancer imaging agents.

A series of [11C]methyl-halo-CGS 27023A analogs (2-F, 1a; 4-F, 1b; 2-Cl, 1c; 3-Cl, 1d; 4-Cl, 1e; 2-Br, 1f; 3-Br, 1g; 4-Br, 1h; 4-I, 1i), novel radiolabeled matrix metalloproteinase (MMP) inhibitors, have been synthesized for evaluation as new potential positron emission tomography (PET) breast cancer imaging agents. The precursors halo-CGS 27023A analogs (2-F, 6a; 4-F, 6b; 2-Cl, 6c; 3-Cl, 6d; 4-Cl, 6e; 2-Br, 6f; 3-Br, 6g; 4-Br, 6h; 4-I, 6i) for radiolabeling were obtained in four steps from starting material amino acid D-valine with moderate to excellent chemical yields. Precursors were labeled by [11C]methyl triflate through 11C-O-methylation method at the aminohydroxyl position under basic conditions and isolated by solid-phase extraction (SPE) purification to produce pure target compounds in 40-60% radiochemical yields (decay corrected to end of bombardment), in 20-25 min synthesis time.