When chronicity meets cyclicity: The cultivation of embodied knowledge and selfhood by cis-gender women with cystic fibrosis.

This article offers the case of cystic fibrosis (CF), a multi-system disease, to illustrate how individuals with chronic illness cultivate and apply embodied knowledge to optimize their well-being. We identified three interrelated processes that occur when disease chronicity and menstrual cyclicity meet: 1) knowledge production with a period-tracking app; 2) application of embodied knowledge to manage life with menstrual-related CF symptoms; 3) cultivation of the body-self as a menstruating woman with CF. These dynamic processes capture how cis-gender women with CF attune to their bodies, navigate their illness, and situate themselves within their lifeworlds. Genetic conditions like CF are apt for studying these processes because adults have managed their disease for decades, with longitudinal experience that often exceeds that of their clinicians. Our evidence elucidates the co-constitutive nature of chronic disease, gendered subjectivity, and biological processes in flux. We explored the menstrual cyclicity of chronic disease symptoms by having 72 participants track their CF symptoms across 4 menstrual cycles on a customized period-tracking app. We performed semi-structured interviews with 20 participants to understand how they interpreted these cyclical CF symptoms. We learned that digital tracking attuned participants to monthly fluctuations in CF symptoms. They applied this knowledge to manage their lives and shape their sense of self. We argue that women with CF produce distinct embodied knowledge during their reproductive years, shaping their illness experience, disease management, overall health, quality of life, and selfhood. The dynamics we describe may reflect broader patterns by which women with other chronic illnesses experience their bodies and understand themselves in the world.

Prokaryotic microbial ecology as an ecosurveillance tool for eukaryotic pathogen colonisation: Meiothermus and Naegleria fowleri.

Naegleria fowleri has been detected in drinking water distribution systems (DWDS) in Australia, Pakistan and the United States and is the causative agent of the highly fatal disease primary amoebic meningoencephalitis. Previous small scale field studies have shown that Meiothermus may be a potential biomarker for N. fowleri. However, correlations between predictive biomarkers in small sample sizes often breakdown when applied to larger more representative datasets. This study represents one of the largest and most rigorous temporal investigations of Naegleria fowleri colonisation in an operational DWDS in the world and measured the association of Meiothermus and N. fowleri over a significantly larger space and time in the DWDS. A total of 232 samples were collected from five sites over three-years (2016-2018), which contained 29 positive N. fowleri samples. Two specific operational taxonomic units assigned to M. chliarophilus and M. hypogaeus, were significantly associated with N. fowleri presence. Furthermore, inoculation experiments demonstrated that Meiothermus was required to support N. fowleri growth in field-collected biofilms. This validates Meiothermus as prospective biological tool to aid in the identification and surveillance of N. fowleri colonisable sites.

Naegleria fowleri Detected in Grand Teton National Park Hot Springs.

The free-living thermophilic amoeba Naegleria fowleri (N. fowleri) causes the highly fatal disease primary amoebic meningoencephalitis. The environmental conditions that are favorable to the growth and proliferation of N. fowleri are not well-defined, especially in northern regions of the United States. In this study, we used culture-based methods and multiple molecular approaches to detect and analyzeN. fowleri and other Naegleria spp. in water, sediment, and biofilm samples from five hot spring sites in Grand Teton National Park, Wyoming, U.S.A. These results provide the first detections of N. fowleri in Grand Teton National Park and provide new insights into the distribution of pathogenic N. fowleri and other nonpathogenic Naegleria spp. in natural thermal water systems in northern latitudes.

Measuring the longitudinal impact of a transgender and gender diverse curriculum on nurse practitioner students' and nurse practitioners' cultural competence, knowledge, skills, and attitudes.

ABSTRACT: Nurse practitioners (NPs) are well positioned to provide inclusive, person-centered care to patients who are transgender and gender diverse (TGD); however, few NPs have been trained on how to do so. This study demonstrates the longitudinal effect of an educational intervention that used readings, lecture, a patient panel, and a standardized patient encounter on NPs' and nurse practitioner students' cultural competency, knowledge, skills, and attitudes toward patients who are TGD. The study followed participants for 3 months and used the Sexual Orientation Counselor Competency Scale version 3 tool to measure changes across three data points. Significant improvements were demonstrated in cultural competency and clinical skills, with knowledge and attitude increases that did not reach significances. The findings from this study have implications for the inclusion of TGD content in graduate nursing curriculum and continuing education activities and provide educators with best practices to integrate this content into learning activities.

Treatment performance and microbial community structure in an aerobic granular sludge sequencing batch reactor amended with diclofenac, erythromycin, and gemfibrozil.

This study characterizes the effects of three commonly detected pharmaceuticals-diclofenac, erythromycin, and gemfibrozil-on aerobic granular sludge. Approximately 150 µg/L of each pharmaceutical was fed in the influent to a sequencing batch reactor for 80 days, and the performance of the test reactor was compared with that of a control reactor. Wastewater treatment efficacy in the test reactor dropped by approximately 30-40%, and ammonia oxidation was particularly inhibited. The relative abundance of active Rhodocyclaceae, Nitrosomonadaceae, and Nitrospiraceae families declined throughout exposure, likely explaining reductions in wastewater treatment performance. Pharmaceuticals were temporarily removed in the first 12 days of the test via both sorption and degradation; both removal processes declined sharply thereafter. This study demonstrates that aerobic granular sludge may successfully remove pharmaceuticals in the short term, but long-term tests are necessary to confirm if pharmaceutical removal is sustainable.

Managing Prognosis in Precision Medicine: Utility, Imagination, and Communication.

Research on how physicians predict and communicate prognosis focuses primarily on end-of-life care. Unsurprisingly, as genomic technology gains traction as a prognostic tool, the focus has also been on terminality, with research focused on how genetic results may be used to terminate pregnancies or redirect care towards palliation for neonates. However, genomic results also have powerful impacts on how patients who live prepare for their futures. Genomic testing provides broad-reaching and early-albeit complex, uncertain, and shifting-prognostic information. In this essay, we argue that as genomic testing occurs earlier and increasingly in a screening context, researchers and clinicians must strive to understand and manage the prognostic implications of results. While our understanding of the psychosocial and communicational aspects of prognosis in symptomatic populations is incomplete, it has progressed further than our understanding in a screening context and therefore provides useful lessons and feasible opportunities for further research. By providing an interdisciplinary and inter-specialty perspective on the psychosocial and communicational aspects of prognosis in genetics, we discuss prognostication with respect to genetics from the neonatal period through adulthood, highlighting medical specialties and patient populations that are especially informative for considering the longitudinal management of prognostic information in genomic medicine.

Gunther Tulip Filter Strut Penetration: Benign Long-Term Follow-up.

PURPOSE: To describe the natural history of Gunther Tulip filter (GTF) strut penetration based on the computed tomography (CT)-documented distance penetrated over time and any clinical manifestations. MATERIALS AND METHODS: The records of 203 patients (mean age, 59.1 years; 59.4% men) who had had an infrarenal GTF placed for venous thromboembolism (84.2%) with contraindications to anticoagulation (95.1%) and had CT follow-up were reviewed retrospectively for clinical or imaging evidence of complications. Filter strut penetration was measured on axial images from the outer caval wall to the inner edge of the distal end of each strut. Filter strut behavior over time was modeled using a linear mixed model. RESULTS: The extent of penetration correlated positively with filter dwell time (P < .001) but plateaued at 3.3 mm at 10-year follow-up. At median 4.7-year follow-up 79.3% of patients had at least 1 strut that was >0.2 mm and 31% had a strut >3 mm from the inferior vena caval wall. The extent of strut penetration was greater at all time points for women (P = .002). Abutment or entry into an adjacent structure was identified in 183 struts of 105 (52.7%) filters; of the 80 filters with CT follow-up, 47% showed progression and 19% regressed. There were no symptoms referable to filter strut penetration. CONCLUSIONS: GTF struts often penetrate the inferior vena cava progressively; however, this tends to plateau by 10 years. The limited long-term progression and a very low incidence of symptomatic complications together support a noninterventional approach to the finding of an asymptomatic GTF strut penetration.

Development of Martian saline seep models and their implications for planetary protection.

While life on Mars has not been found, Earth-based microorganisms may contaminate the Red Planet during rover expeditions and human exploration. Due to the survival advantages conferred by the biofilm morphology to microorganisms, such as resistance to UV and osmotic stress, biofilms are particularly concerning from a planetary protection perspective. Modeling and data from the NASA Phoenix mission indicate that temporary liquid water might exist on Mars in the form of high salinity brines. These brines could provide colonization opportunities for terrestrial microorganisms brought by spacecraft or humans. To begin testing for potential establishment of microbes, results are presented from a simplified laboratory model of a Martian saline seep inoculated with sediment from Hailstone Basin, a terrestrial saline seep in Montana (USA). The seep was modeled as a sand-packed drip flow reactor at room temperature fed media with either 1 M MgSO4 or 1 M NaCl. Biofilms were established within the first sampling point of each experiment. Endpoint 16S rRNA gene community analysis showed significant selection of halophilic microorganisms by the media. Additionally, we detected 16S rRNA gene sequences highly similar to microorganisms previously detected in two spacecraft assembly cleanrooms. These experimental models provide an important foundation for identifying microbes that could hitch-hike on spacecraft and may be able to colonize Martian saline seeps. Future model optimization will be vital to informing cleanroom sterilization procedures.

Bringing Gender-Affirming Care to Primary Care: Use of a Multimodal Curriculum to Educate Nurse Practitioners and Nurse Practitioner Students.

BACKGROUND: An increasing number of individuals who identify as transgender and gender diverse require informed and compassionate health care, yet there is a dearth of research about which educational strategies are best used to provide nurses and nurse practitioners the foundation upon which to provide appropriate health care. PURPOSE: This study evaluated a multimodal approach that included guided readings, a transgender patient panel, standardized patient simulation, and group discussion. METHODS: The Sexual Orientation Counselor Competency Scale was administered pre- and postintervention. RESULTS: Results demonstrated increases in knowledge, skills, and attitudes among the 16 participants. A high level of satisfaction was expressed for the overall program, but especially for the patient panel and standardized patient encounter. CONCLUSIONS: Nurse educators are encouraged to include information about health care of the transgender patient into curricula.

Prognostic imagination: Genetic counseling amidst therapeutic innovation and evolving futures.

Despite the moniker "precision medicine," genetic diagnoses are often imprecise with respect to prognosis. In a period when prognoses are evolving in lockstep with advances in genetic diagnostics and therapeutics, it is critical that clinicians and researchers consider how prognosis is communicated beyond the moment of diagnosis. Research has shown that genetic diagnoses are described differently in pre- and postnatal contexts, but we know relatively little about how patients and families make sense of prognostic information as affected children grow up. Here, I draw on research and personal narratives to describe how prognostic information impacts individuals' conceptions of the future. A deeper understanding of how patients and families view prognosis is important because parents may need support as prognostic conversations arise and because perceptions of prognosis may influence ideas about the future, psychological health, decisions, and planning. By exploring how specific ideas about an individuals' future take hold, clinicians and researchers may begin to identify the benefits, harms, and accuracy of varied sources of prognostic information, opening new areas of bioethical investigation. In closing, I propose prognostic imagination as a useful concept for considering how patients and families experience prognostic information amidst therapeutic innovations and evolving futures.

Summary of the experiences, knowledge, medical management, and family communication of monoallelic MUTYH carriers.

Germline genetic testing for inherited cancer risk is increasingly being performed with multigene panel testing with MUTYH often included on colorectal cancer- and polyposis-focused panels, as well as on broader pan-cancer panels. With up to 1%-2% of the general population being monoallelic MUTYH carriers, pathogenic/likely pathogenic (P/LP) variants in MUTYH are one of the most common findings on multigene cancer panels. However, little is known about patient experience and understanding of monoallelic MUTYH P/LP variants, nor whether such findings influence medical management recommendations and familial communication, which this study aims to better understand. Monoallelic P/LP MUTYH carriers were recruited from the Prospective Registry of Multiplex Testing (PROMPT) and completed a cross-sectional self-report survey on sociodemographic characteristics, medical and family history, experiences with MUTYH genetic testing, genetics and MUTYH knowledge, perceived cancer risk, and familial communication. Of 115 eligible PROMPT participants, 49 (43%) completed the survey who were primarily female (94%), white (96%), had a history of cancer (61%), and a median age of 51.4 years. Most participants (61%) reported satisfaction with how their healthcare provider managed their genetic test result and care, and 65% of survey participants reported their provider recommended colonoscopy based on their genetic test results. Participants' responses also reflected variable levels of knowledge regarding cancer risks and screening recommendations for MUTYH carriers. The majority (98%) of participants shared their genetic test results with at least some of their relatives; however, only 13% of eligible relatives reportedly underwent cascade testing. Taken together, this study provides needed insight into the overall experiences of monoallelic MUTYH carriers and highlights numerous areas for improvement in clinician education, communication, and management of these individuals.

Using Live-Cell Imaging to Measure the Effects of Pathological Proteins on Axonal Transport in Primary Hippocampal Neurons.

Bidirectional transport of cargos along the axon is critical for maintaining functional synapses, neural connectivity, and healthy neurons. Axonal transport is disrupted in multiple neurodegenerative diseases, and projection neurons are particularly vulnerable because of the need to transport cellular materials over long distances and sustain substantial axonal mass. Pathological modifications of several disease-related proteins negatively affect transport, including tau, amyloid-ß, α-synuclein, superoxide dismutase, and huntingtin, providing a potential common mechanism by which pathological proteins exert toxicity in disease. Methods to study these toxic mechanisms are necessary to understand neurodegenerative disorders and identify potential therapeutic interventions. Here, cultured primary rodent hippocampal neurons are co-transfected with multiple plasmids to study the effects of pathological proteins on fast axonal transport using live-cell confocal imaging of fluorescently-tagged cargo proteins. We begin with the harvest, dissociation, and culturing of primary hippocampal neurons from rodents. Then, we co-transfect the neurons with plasmid DNA constructs to express fluorescent-tagged cargo protein and wild-type or mutant tau (used as an exemplar of pathological proteins). Axons are identified in live cells using an antibody that binds an extracellular domain of neurofascin, an axon initial segment protein, and an axonal region of interest is imaged to measure fluorescent cargo transport. Using KymoAnalyzer, a freely available ImageJ macro, we extensively characterize the velocity, pause frequency, and directional cargo density of axonal transport, all of which may be affected by the presence of pathological proteins. Through this method, we identify a phenotype of increased cargo pause frequency associated with the expression of pathological tau protein. Additionally, gene-silencing shRNA constructs can be added to the transfection mix to test the role of other proteins in mediating transport disruption. This protocol is easily adaptable for use with other neurodegenerative disease-related proteins and is a reproducible method to study the mechanisms of how those proteins disrupt axonal transport.

The Impact of Transmissible Microbes: How the Cystic Fibrosis Community Mobilized Against Cepacia.

Long before COVID-19 made social distancing familiar, people with cystic fibrosis (CF) already practiced such behaviors. CF is held up as a classic example of genetic disease, yet people with CF are also susceptible to bacteria from the environment and from other CF patients. Starting in the 1980s, a bacterial epidemic in the CF population highlighted clashing priorities of connection, physical safety, and environmental protection. Policymakers ultimately called for the physical separation of people with CF from one another via recommendations that reconfigured the CF community. Simultaneously, medical researchers recognized that one highly transmissible CF pathogen called cepacia was being developed for environmental applications and got the EPA to limit cepacia's environmental deployment. Environmental regulations speak to the challenge of useful microbes that harm a minority, but CF cross-infection also involves legal implications for microbial and genetic discrimination, social consequences for CF communities, and ethical questions about balancing autonomy, harms, and benefits. As scientists increasingly study connections between host genetics, microbial genetics, and infectious risks, CF is a vital referent.

Longitudinal analysis of the Five Sisters hot springs in Yellowstone National Park reveals a dynamic thermoalkaline environment.

Research focused on microbial populations of thermoalkaline springs has been driven in a large part by the lure of discovering functional enzymes with industrial applications in high-pH and high temperature environments. While several studies have focused on understanding the fundamental ecology of these springs, the small molecule profiles of thermoalkaline springs have largely been overlooked. To better understand how geochemistry, small molecule composition, and microbial communities are connected, we conducted a three-year study of the Five Sisters (FS) springs that included high-resolution geochemical measurements, 16S rRNA sequencing of the bacterial and archaeal community, and mass spectrometry-based metabolite and extracellular small molecule characterization. Integration of the four datasets facilitated a comprehensive analysis of the interwoven thermoalkaline spring system. Over the course of the study, the microbial population responded to changing environmental conditions, with archaeal populations decreasing in both relative abundance and diversity compared to bacterial populations. Decreases in the relative abundance of Archaea were associated with environmental changes that included decreased availability of specific nitrogen- and sulfur-containing extracellular small molecules and fluctuations in metabolic pathways associated with nitrogen cycling. This multi-factorial analysis demonstrates that the microbial community composition is more closely correlated with pools of extracellular small molecules than with the geochemistry of the thermal springs. This is a novel finding and suggests that a previously overlooked component of thermal springs may have a significant impact on microbial community composition.

Measures of Utility Among Studies of Genomic Medicine for Critically Ill Infants: A Systematic Review.

Importance: Genomic medicine holds promise to revolutionize care for critically ill infants by tailoring treatments for patients and providing additional prognostic information to families. However, measuring the utility of genomic medicine is not straightforward and has important clinical and ethical implications. Objective: To review the ways that researchers measure or neglect to measure the utility of genomic medicine for critically ill infants. Evidence Review: This systematic review included prospective full-text studies of genomic medicine of both whole exome and genome sequencing in critically ill infants younger than 1 year. PubMed, Embase, Scopus, and Cochrane Library databases, the Cochrane Database of Systematic Reviews, and the ClinicalTrials.gov register were searched with an English language restriction for articles published from the inception of each database through May 2022. Search terms included variations of the following: gene, sequencing, intensive care, critical care, and infant. From the included articles, information on how utility was defined and measured was extracted and synthesized. Information was also extracted from patient cases that authors highlighted by providing additional information. Spearman rank-order correlation was used to evaluate the association between study size and utility. Findings: Synthesized data from the 21 included studies reflected results from 1654 patients. A mean of 46% (range, 15%-72%) of patients had a positive genetic test result, and a mean of 37% (range, 13%-61%) met the criteria for experiencing utility. Despite heterogeneity in how studies measured and reported utility, a standardized framework was created with 5 categories of utility: treatment change, redirection of care, prognostic information, reproductive information, and screening or subspecialty referral. Most studies omitted important categories of utility, notably personal utility (patient-reported benefits) (20 studies [95%]), utility of negative or uncertain results (15 [71%]), and disutility (harms) (20 [95%]). Studies disproportionally highlighted patient cases that resulted in treatment change. Larger studies reported substantially lower utility (r = -0.65; P = .002). Conclusions and Relevance: This systematic review found that genomic medicine offered various categories of utility for a substantial proportion of critically ill infants. Studies measured utility in heterogeneous ways and focused more on documenting change than assessing meaningful benefit. Authors' decisions about which cases to highlight suggest that some categories of utility may be more important than others. A more complete definition of utility that is used consistently may improve understanding of potential benefits and harms of genetic medicine.

Root exudate composition reflects drought severity gradient in blue grama (Bouteloua gracilis).

Plant survival during environmental stress greatly affects ecosystem carbon (C) cycling, and plant-microbe interactions are central to plant stress survival. The release of C-rich root exudates is a key mechanism plants use to manage their microbiome, attracting beneficial microbes and/or suppressing harmful microbes to help plants withstand environmental stress. However, a critical knowledge gap is how plants alter root exudate concentration and composition under varying stress levels. In a greenhouse study, we imposed three drought treatments (control, mild, severe) on blue grama (Bouteloua gracilis Kunth Lag. Ex Griffiths), and measured plant physiology and root exudate concentration and composition using GC-MS, NMR, and FTICR. With increasing drought severity, root exudate total C and organic C increased concurrently with declining predawn leaf water potential and photosynthesis. Root exudate composition mirrored the physiological gradient of drought severity treatments. Specific compounds that are known to alter plant drought responses and the rhizosphere microbiome mirrored the drought severity-induced root exudate compositional gradient. Despite reducing C uptake, these plants actively invested C to root exudates with increasing drought severity. Patterns of plant physiology and root exudate concentration and composition co-varied along a gradient of drought severity.

Chickensplash! Exploring the health concerns of washing raw chicken.

The Food and Drug Administration recommends against washing raw chicken due to the risk of transferring dangerous food-borne pathogens through splashed drops of water. Many cooks continue to wash raw chicken despite this warning, however, and there is a lack of scientific research assessing the extent of microbial transmission in splashed droplets. Here, we use large agar plates to confirm that bacteria can be transferred from the surface of raw chicken through splashing. We also identify and create a phylogenetic tree of the bacteria present on the chicken and the bacteria transferred during splashing. While no food-borne pathogens were identified, we note that organisms in the same genera as pathogens were transferred from the chicken surface through these droplets. Additionally, we show that faucet height, flow type, and surface stiffness play a role in splash height and distance. Using high-speed imaging to explore splashing causes, we find that increasing faucet height leads to a flow instability that can increase splashing. Furthermore, splashing from soft materials such as chicken can create a divot in the surface, leading to splashing under flow conditions that would not splash on a curved, hard surface. Thus, we conclude that washing raw chicken does risk pathogen transfer and cross-contamination through droplet ejection, and that changing washing conditions can increase or decrease the risk of splashing.

Isolation and Characterization of Lignocellulose-Degrading Geobacillus thermoleovorans from Yellowstone National Park.

The microbial degradation of lignocellulose in natural ecosystems presents numerous biotechnological opportunities, including biofuel production from agricultural waste and feedstock biomass. To explore the degradation potential of specific thermophiles, we have identified and characterized extremophilic microorganisms isolated from hot springs environments that are capable of biodegrading lignin and cellulose substrates under thermoalkaline conditions, using a combination of culturing, genomics, and metabolomics techniques. Organisms that can use lignin and cellulose as a sole carbon source at 60 to 75°C were isolated from sediment slurry of thermoalkaline hot springs (71 to 81°C and pH 8 to 9) of Yellowstone National Park. Full-length 16S rRNA gene sequencing indicated that these isolates were closely related to Geobacillus thermoleovorans. Interestingly, most of these isolates demonstrated biofilm formation on lignin, a phenotype that is correlated with increased bioconversion. Assessment of metabolite level changes in two Geobacillus isolates from two representative springs were undertaken to characterize the metabolic responses associated with growth on glucose versus lignin carbon source as a function of pH and temperature. Overall, results from this study support that thermoalkaline springs harbor G. thermoleovorans microorganisms with lignocellulosic biomass degradation capabilities and potential downstream biotechnological applications. IMPORTANCE Since lignocellulosic biomass represents a major agro-industrial waste and renewable resource, its potential to replace nonrenewable petroleum-based products for energy production is considerable. Microbial ligninolytic and cellulolytic enzymes are of high interest in biorefineries for the valorization of lignocellulosic biomass, as they can withstand the extreme conditions (e.g., high temperature and high pH) required for processing. Of great interest is the ligninolytic potential of specific Geobacillus thermoleovorans isolates to function at a broad range of pH and temperatures, since lignin is the bottleneck in the bioprocessing of lignocellulose. In this study, results obtained from G. thermoleovorans isolates originating from YNP springs are significant because very few microorganisms from alkaline thermal environments have been discovered to have lignin- and cellulose-biodegrading capabilities, and this work opens new avenues for the biotechnological valorization of lignocellulosic biomass at an industrial scale.

Seasonal variation and potential roles of dark septate fungi in an arid grassland.

High temperatures and extended drought in temperate and tropical arid ecosystems promote the colonization of diverse microenvironments by dark septate fungi (DSF). These fungi contribute to soil nutrient cycling, soil stabilization, and plant survival, but the roles of individual DSF species, their distributions, and their community diversity are poorly understood. The objective of this study was to evaluate the distribution, seasonal variation, and potential roles of DSF on plant growth. We collected biocrust (lichen-, moss-, and cyanobacterium-dominated biocrusts) soils at different depths and rhizosphere soils from two grasses, Bromus tectorum and Pleuraphis jamesii, in an arid grassland near Moab, Utah, USA. Seasonal variation of DSF was evaluated using culture-based approaches and compared with fungal community profiles from next-generation sequencing (NGS). Culturing showed that DSF were 30% more abundant in biocrusts compared with the focal rhizospheres. The abundance of DSF varied seasonally in belowground samples (rhizosphere and below-biocrust), with a significant increase during the summer months. Pleosporales was the dominant order (35%) in both biocrust and rhizosphere soils out of 817 isolated fungi. Dominant DSF genera in culture included Alternaria, Preussia, Cladosporium, Phoma, and an unknown Pleosporales. Similar results were observed in biocrust and rhizosphere soils NGS. Further, seed germination experiments using dominant taxa were conducted to determine their potential roles on germination and seedling growth using maize as a model plant. Cladosporium and unknown Pleosporales isolates showed plant growth-promoting ability. The variation in abundance of DSF, their differential occurrence in different microenvironments, and their ability to grow in a xerotolerant medium reflect adaptations to summer environmental conditions and to changes in the abundance of organic matter, as well as a potential increase in plant investment in these fungi when heat and drought stresses are more severe.