RESUMEN
Desert soil hosts many microorganisms, whose activities are essential from an ecological viewpoint. Moreover, they are of great anthropic interest. The knowledge of extreme environments microbiomes may be beneficial for agriculture, technology, and human health. In this study, 11 Arthrobacter strains from topsoil samples collected from the Great Gobi A Strictly Protected Area in the Gobi Desert, were characterized by a combination of different techniques. The phylogenetic analysis, performed using their 16S rDNA sequences and the most similar Arthrobacter sequences found in databases, revealed that most of them were close to A. crystallopoietes, while others joined a sister group to the clade formed by A. humicola, A. pascens, and A. oryzae. The resistance of each strain to different antibiotics, heavy-metals, and NaCl was also tested as well as the inhibitory potential against human pathogens (i.e., Burkholderia ssp., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus ssp.) via cross-streaking, to check the production of metabolites with antimicrobial activity. Data obtained revealed that all strains were resistant to heavy metals and were able to strongly interfere with the growth of many of the human pathogens tested. The volatile organic compounds (VOCs) profile of the 11 Arthrobacter strains was also analyzed. A total of 16 different metabolites were found, some of which were already known for having an inhibitory action against different Gram-positive and Gram-negative bacteria. Isolate MS-3A13, producing the highest quantity of VOCs, is the most efficient against Burkholderia cepacia complex (Bcc), K. pneumoniae, and coagulase-negative Staphylococci (CoNS) strains. This work highlights the importance of understanding microbial populations' phenotypical characteristics and dynamics in extreme environments to uncover the antimicrobial potential of new species and strains.
RESUMEN
Understanding how microbial communities survive in extreme environmental pressure is critical for interpreting ecological patterns and microbial diversity. Great Gobi A Strictly Protected Area represents an intriguing model for studying the bacterial community since it is a protected and intact wild area of the Mongolian desert. In this work, the composition of a bacterial community of the soil from four oases was characterized by extracting total DNA and sequencing through the Illumina NovaSeq platform. In addition, the soil's chemical and physical properties were determined, and their influence on shaping the microbial communities was evaluated. The results showed a high variability of bacterial composition among oases. Moreover, combining specific chemical and physical parameters significantly shapes the bacterial community among oases. Data obtained suggested that the oases were highly variable in physiochemical parameters and bacterial communities despite the similar extreme climate conditions. Moreover, core functional microbiome were constituted by aerobic chemoheterotrophy and chemoheterotrophy, mainly contributed by the most abundant bacteria, such as Actinobacteriota, Pseudomonadota, and Firmicutes. This result supposes a metabolic flexibility for sustaining life in deserts. Furthermore, as the inhabitants of the extreme regions are likely to produce new chemical compounds, isolation of key taxa is thus encouraged.
RESUMEN
The mechanisms of interactions between apex and smaller carnivores may range from competition to facilitation. Conversely, interactions between predators and prey are mainly driven by the prey reducing the likelihood of encounters with predators. In this study, we investigated (1) the spatiotemporal interactions between an apex (the snow leopard) and a meso-predator (the red fox), and (2) the temporal interactions between the snow leopard and its potential prey (Siberian ibex, argali, Asian wild ass, Tolai hare) through camera trapping in the Mongolian Great Gobi-A. The probability of occurrence for the red fox was higher in the presence of the snow leopard than in its absence. Moreover, the red fox activity pattern matched that of the snow leopard, with both species mostly active at sunset. This positive spatiotemporal interaction suggests that the presence of the snow leopard may be beneficial for the red fox in terms of scavenging opportunities. However, other explanations may also be possible. Amongst prey, the Siberian ibex and the argali were mainly active during the day, whereas the Asian wild ass and the Tolai hare were more nocturnal. These findings suggest that potential prey (especially the Siberian ibex and the argali) may shape their behavior to decrease the opportunity for encounters with the snow leopard. Our results have revealed complex interactions between apex and smaller predators and between apex predator and its potential prey.
RESUMEN
Mammalian communities inhabiting temperate grasslands are of conservation concern globally, especially in Central Asia, where livestock numbers have dramatically increased in recent decades, leading to overgrazing and land-use change. Yet, how this pervasive presence of livestock herds affects the community of wild mammals remains largely unstudied. We used systematic camera trapping at 216 sites across remote, mountainous areas of the Mongolian Altai Mountains to assess the spatial and temporal patterns of occurrence and the interspecific relationships within a mammalian community that includes different categories of livestock. By adopting a recently proposed multispecies occupancy model that incorporates interspecific correlation in occupancy, we found several statistically strong correlations in occupancy among species pairs, with the majority involving livestock. The sign of such associations was markedly species-dependent, with larger wild species of conservation concern, namely, snow leopard and Siberian ibex, avoiding livestock presence. As predicted, we found evidence of a positive correlation in occupancy between predators and their respective main prey. Contrary to our expectations, a number of intraguild species pairs also showed positive co-occurrence, with no evidence of spatiotemporal niche partitioning. Overall, our study suggests that livestock encroaching into protected areas influences the whole local community of wild mammals. Though pastoralism has coexisted with wildlife for millennia in central Asian grasslands, our findings suggest that policies and practices to decrease the pressure of livestock husbandry on wildlife are needed, with special attention on large species, such as the snow leopard and its wild prey, which seem to be particularly sensitive to this pervasive livestock presence.