Microbial mat ecosystems: structure types, functional diversity, and biotechnological application

Microbial mats are horizontally stratified microbial communities, exhibiting a structure defined by physiochemical gradients, which models microbial diversity, physiological activities, and their dynamics as a whole system. These ecosystems are commonly associated with aquatic habitats, including hot springs, hypersaline ponds, and intertidal coastal zones and oligotrophic environments, all of them harbour phototrophic mats and other environments such as acidic hot springs or acid mine drainage harbour non-photosynthetic mats. This review analyses the complex structure, diversity, and interactions between the microorganisms that form the framework of different types of microbial mats located around the globe. Furthermore, the many tools that allow studying microbial mats in depth and their potential biotechnological applications are discussed.

Respiratory Function and Symptoms Post Cold Air Exercise in Female High and Low Ventilation Sport Athletes

PURPOSE: Cold weather exercise is common in many regions of the world; however, it is unclear whether respiratory function and symptom worsen progressively with colder air temperatures. Furthermore, it is unclear whether high-ventilation sport background exacerbates dysfunction and symptoms. METHODS: Seventeen active females (measure of the maximum volume of oxygen [VO(2max)]: 49.6±6.6 mL·kg⁻¹·min⁻¹) completed on different days in random order 5 blinded running trials at 0℃, -5℃, -10℃, -15℃, and -20℃ (humidity 40%) in an environmental chamber. Distance, heart rate, and rating of perceived exertion (RPE) were measured within each trial; forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow at 25%-75% (FEF₂₅₋₇₅), and forced expiratory flow at 50% (FEF₅₀) were measured pre- and post-test (3, 6, 10, 15, and 20 minutes). Respiratory symptoms and global effort were measured post-test spirometry. RESULTS: Mean decreases were found in FEV1 (4%-5% at 0℃, -5℃, -10℃, and -15℃; 7% at -20℃). FEF₂₅₋₇₅ and FEF₅₀ decreased 7% and 11% at -15℃ and -20℃, respectively. Post-exertion spirometry results were decreased most at 3 to 6 minutes, recovering back to baseline at 20 minutes. Respiratory symptoms and global effort significantly increased at -15℃ and -20℃ with decreased heart rate. High-ventilation sports decreased function more than low-ventilation participants but had fewer symptoms. CONCLUSIONS: These results indicate that intense exercise at cold air temperatures up to -20℃ is achievable; however, greater effort along with transient acute bronchoconstriction and symptoms of cough after exercising in temperatures colder than -15℃ are likely. It is recommended that individuals cover their mouth and reduce exercise intensity to ameliorate the effects of cold weather exercise.

Extreme environment: Biofilms and microbial diversity

@#Extreme environments have been the interest of numerous studies and scientific publications. For many years, these environmental roles, which are characterised by high or low temperatures, high-pressure, low pH, high salt concentrations and companions of two or more extreme parameters. For many years, these environmental niches have increased in importance due to extreme microorganisms diversity and their potential returns of several industrial production processes concerning the food fields, medical and pharmaceutical. At present, it's possible to detect life in most extreme environments, from the deep sea hot springs, depth of the oceans, deep inside the earth crust, harsh chemical environments, and high radiation environments through metagenomics analysis. In this review, newly identified microorganisms, and their potential uses in several applied fields have been outlined. The microbial development in biofilms form has supported the survival of alkaliphiles, psychrophile, halophile thermophile and extremophile microorganisms; where they flourish due to the adaptation strategies involving complex variation in biofilms structure and behaviours.

STUDIES ON BIOLOGICAL CHARACTERISTICS OF HALOPHILIC ACTINOMYCETES / 微生物学通报

Studies on NaCl concentration, pH tolerance and selectivity to different concent rations of Na +, K +, Mg 2+ and Ca 2+ of 43 isolates from th e saline soils in XinJiang, HeBei and QingHai Provinces of China and 4 type stra ins were performed in this paper Results showed that halotolerant actinomycete s have extensiv e adaptability to Na +, K + and Mg 2+ and only a few of them can grow in low CaCl 2 concentration Halophilic actinomycetes have extensive adaptability to Na +, and for most halophilic actinomycetes, Na + can be substituted by K + , Mg 2+ , but not for Ca 2+ For some halophilic actinomycetes , it is necessary to have Na + for their growth It also showed that the growth of al l halophilic actinomycetes had se lectivity with different concentration of Na +, K +, Mg 2+ So it is pre sumed that only Kaliumphilic or Magnesiumphilic Actinomycetes maybe exist in hig h salt environments In addition, the growth pH range were 6 0～9 0 and the o ptimum pH were 7 0～8 0 not only for halophilic but also for halotolerant acti nomycetes The dis tribution of halophilic actinomycetes also have some relativity to isolation sit es