Because the cytoskeleton integrity is involved in the metabolic regulation of mitochondrial respiration and energy fluxes, microfilaments may be expected to result in altered mitochondrial functions. This correlation occurred in our in vitro model of hyperthermia, as brief but repeated exposures of cells to 43uC concomitantly disrupted selected mitochondrial functions and cytoskeletal organization. The adverse effects of temperature on SC functions shown in this study to occur in cultured SC after relatively brief and widely spaced exposures to moderate hyperthermia may be representative of what occurs in vivo. A SC cytoskeleton in good shape plays key roles in the maintenance of normal spermatogenesis, as it is involved in the anchoring, translocation and guide of germ cells through the multiple and admirably orchestrated stages of their differentiation. Cytoskeletal functions involve intracellular PF-04217903 transport of vesicles and particles, including phagocytized lipid-rich apoptotic and residual bodies released from developing germ cells, displacement on the SC luminal surface of maturing spermatids as the latter become ready to be released as nascent spermatozoa to the seminiferous tubule lumen, and secretion of the luminal fluid required for sperm propulsion out of the testis. All of these functions rely on an adequate supply of ATP, which may be decreased by mitochondrial dysfunction of any cause, including temporary exposures to hyperthermia. That mitochondrial functions are temperature-disturbed in SC is revealed in this study by different criteria, comprising modified lipid homeostasis, reduced levels of fatty acid oxidation and DPG biosynthesis. Because normal spermatogenesis is strictly dependent upon optimal SC functions, these changes could be expected to eventually MK-2206 Akt inhibitor compromise the role of these cells as spermatogenesis supporters, thereby contributing to the temperature-associated germ cell apoptosis and temporal cessation of the spermatogenic activity induced by hyperthermia. Once these temperature-induced perturbations are surmounted, SC may be able to resume their normal functions, including phagocytosis followed by catabolism and disposal of germ cell-derived materials, as shown in the rat some time after cessation of hyperthermia exposures. However small and potentially reversible, the additive damaging consequences on SC of regularly spaced but daily repeated exposures to moderate hyperthermia may become irreversible if not interrupted. Exposures of this type are not impossible in the case of men; they may evidently occur in those daily exposed to heat for occupational reasons but also inadvertently in those with hot water bathing habits, for such exposures may be considered as a factor when evaluating reduced male fertility. In the recent past, microorganisms, associated with multicellular organisms, have been receiving increasing attention as a driving factor in ecosystems. Endophytes in plants can change host growth and shoot production by altering nutrient uptake, secondary metabolite production or defense mechanisms. Moreover, endophytes can be parasites and thereby play a crucial role in ecosystems by controlling the dynamics of host populations, by regulating host abundances and, thus, by contributing to ecosystem stability.