Background: Biosurfactants are amphiphilic surface active compounds that produced by several microorganisms, including, bacteria and fungi. Biodegradability, low toxicity, applications diversity and functionality under extreme conditions are characterized them from chemically biosurfactants. It is found that, Rhodotorula species, read yeasts, have high potency for biosurfactant producing. Recently, antimicrobial activities of biosurfactants have been subjected for new antibiotic therapy. The aim of the present study was to evaluate biosurfactant production by the different strains of Rhodotorula species in laboratory conditions. In addition, antifungal activity of produced biosurfactant was assessed against several saprophytic fungi. In the present study 54 strains of Rhodotorula including, R. glutinis (48 strains), R. minuta (2 strains), R. mucilaginosa (2 strains) and Rhodotorula species (2 strains) were screened for biosurfactant production. The biosurfactant was produced using the Sabouraud dextrose broth medium and confirmed by specific tests. Antifungal assay was also evaluated by disk diffusion method and the serial dilutions of biosurfactant. In the present study, although all tested strains were capable to produce biosurfactant in vitro, the degree of biosurfactant production was varied among stains. 7.4% strains had the highest (+5) biosurfactant activity followed by 16.7%, 29.5%, 25.8% and 20.4% had +4, +3, +2 and +1, respectively. In the present study, all tested fungi were inhibited at 40 µl of biosurfactant. Rhodotorula species are appropriate organisms for the production of biosurfactants and R. glutinis strains have the greatest ability to producing biosurfactant than another species. Furthermore, our results were demonstrated that the produced biosurfactant by R. glutinis presented a valuable potential for biopharmaceutical applications.

A saprophytic soil fungus, Aspergillus flavus, produces aflatoxin (toxigenic strains) in the kernels of corn (Zea mays L.) and seeds of many other crops. Many strains of A. flavus do not produce toxigenic aflatoxin, and soil application of these atoxigenic strains is a suppressive control tactic to assist in controlling toxigenic conspecifics. Effects of atoxigenic A. flavus applications on honey bees (Apis mellifera L.) and other bees are unknown, and basic information on bee occurrences in corn fields treated with and without this biological pesticide is needed to inform integrated pest management in corn. Fields with atoxigenic A. flavus applications were compared to nearby control fields in three counties in corn production regions in eastern Texas. In each corn field, twenty bee bowl traps were deployed along four equal transects located between corn rows, with contents of the bowls (i.e. bees) retrieved after 24 hours. Eleven bee genera from four families were collected from corn fields, with only two honey bees collected and zero honey bees observed in transects. The sweat bee genus Agapostemon (primarily composed of the Texas-striped sweat bee A. texanus) was most abundant in corn fields (44% of the total number of bees collected) followed by long-horned bees (Melissodes spp., 24%). The southernmost county (i.e. San Patricio) produced over 80% of the total number of bees collected. Bee communities occurring in corn production fields with applications of atoxigenic A. flavus applications were not significantly different from nearby control fields. While little is known of bee resource use in corn production systems in Texas, the abundant yet variable bee communities across latitudes in this study suggests a need to investigate the influence of farming practices on bee resources in regional corn production systems.

A total of 281 guano samples were collected from caves (N = 181) in 8 European countries (Bulgaria, Czech Republic, France, Hungary, Italy, Romania, Slovakia and Slovenia) and attics in the Czech R. (N = 100). The correlation of detection of mycobacteria between Ziehl-Neelsen (ZN) microscopy and culture examination and qPCR was strong. ZN microscopy was positive in guano from caves (58.6%) more than double than positivity in guano from attics (21.0%; P <0.01). From 89 mycobacterial isolates (73 isolates from cave guano and 16 isolates from attics’ guano) 68 (76.4%) isolates of 19 sp., ssp. and complex were identified as members of 3 Groups (M. fortuitum, M. chelonae, and M. mucogenicum), and 4 Complexes (M. avium, M. terrae, M. vaccae, and M. smegmatis). A total of 20 isolates (22,5%) belonged to risk group 1 (environmental saprophytes), 48 isolates (53.9%) belonged to risk group 2 (potential pathogens), and none of isolates belonged to risk group 3 (obligatory pathogens). When comparing bat guano collected from caves and attics, differences (P<0.01; Mann-Whitney test) were observed for the electrical conductivity, total carbon, total organic and total inorganic carbon. None difference (P> 0.05; Mann-Whitney test) was found for pH and oxidation-reduction potential parameters.

Pathogens such as bacteria, fungi and viruses are important components of soil and aquatic communities, where they can benefit from decaying and living organic matter, and may opportunistically infect human and animal hosts. One-third of human infectious diseases is constituted by sapronotic disease agents that are natural inhabitants of soil or aquatic ecosystems. They are capable of existing and reproducing in the environment outside of the host for extended periods of time. However, as ecological research on sapronosis is infrequent and epidemiological models are even rarer, very little information is currently available. Their importance is overlooked in medical and veterinary research, as well as the relationships between free environmental forms and those that are pathogenic. Here, using dynamical models in realistic aquatic metacommunity systems, we analyze sapronosis transmission, using the human pathogen Mycobacterium ulcerans that is responsible for Buruli ulcer. Our work constitutes the first set of metacommunity models of sapronotic disease transmission, and is highly flexible for adaptation to other types of sapronosis. The importance of sapronotic agents on animal and human disease burden needs better understanding and new models of sapronosis disease ecology to guide the management and prevention of this important group of pathogens.