Lipoxins (Lxs) and aspirin-triggered epi-Lxs (15-epi-LxA 4 ) act through the ALX/FPRL1 receptor to block leukocyte trafficking, dampen cytokine/chemokine synthesis, and enhance phagocytic clearance of apoptotic leukocytes-key requisites for inflammatory resolution. Although studies using primarily inbred rodents have highlighted resolution as an active event, little is known about the role resolution pathways play in controlling the duration/profile of inflammatory responses in humans. To examine this, we found two types of responders to cantharidin-induced skin blisters in male healthy volunteers: those with immediate leukocyte accumulation and cytokine/chemokine synthesis followed by early resolution and a second group whose inflammation increased gradually over time followed by delayed resolution. In early resolvers, blister 15-epiLxA 4 and leukocyte ALX were low, but increased as inflammation abated. In contrast, in delayed resolvers, 15-epi-LxA 4 and ALX were high early in the response but waned as inflammation progressed. Elevating 15-epi-LxA 4 in early resolvers using aspirin increased blister leukocyte ALX but reduced cytokines/chemokines as well as polymorphonuclear leukocyte and macrophage numbers. These findings show that two phenotypes exist in humans with respect to inflammation severity/longevity controlled by proresolution mediators, namely 15-epi-LxA 4 . These data have implications for understanding the etiology of chronic inflammation and future directions in antiinflammatory therapy.eicosanoids | inflammation | leukocytes
Mammalian Sterile20-like kinase 1 (Mst1) is a ubiquitously expressed serine/threonine kinase which represents a member of the rapidly expanding family of enzymes related to the yeast Sterile20 kinase. Although the physiological function of Mst1 and its role in intracellular signalling is still unclear, reports to date suggest that Mst1, similar to its yeast homologue, operates in the MAPK (mitogen-activated protein kinase) pathway and, in this capacity, may represent a putative MAPK kinase kinase kinase. Moreover, there is abundant evidence for a role of this enzyme in apoptosis, where not only is it a target for caspases, but may also serve as an activator of these proteases to amplify the apoptotic signalling pathway. This paper reviews the investigations that have led to our current understanding of the mechanisms by which Mst1 may be activated and thereby contribute to apoptosis.
We have examined the role of caspasemediated cleavage of the Ste20-like kinases, mammalian sterile 20-like 1 and 2 (Mst1/Mst2), in the mechanism of human eosinophil and neutrophil apoptosis. Initial measurements of kinase activity, using myelin basic protein (MBP) as a substrate in "in-gel" renaturation assays, showed that constitutive eosinophil and neutrophil apoptosis were associated temporally with the activation of a 36-kd MBP kinase (p36 MBPK) and a 34-kd MBP kinase (p34 MBPK), respectively. A constitutively active 63-kd MBP kinase (p63 MBPK) was also detected in freshly prepared eosinophils but not neutrophils,
A Mucoralean fungus was isolated from Caatinga soil of Pernambuco, Northeast of Brazil, and was identified as Cunninghamella echinulata by morphological, physiological, and biochemical tests. This strain was evaluated for biosurfactant/bioemulsifier production using soybean oil waste (SOW) and corn steep liquor (CSL) as substrates, added to basic saline solution, by measuring surface tension and emulsifier index and activity. The best results showed the surface water tension was reduced from 72 to 36 mN/m, and an emulsification index (E24) of 80% was obtained using engine oil and burnt engine oil, respectively. A new molecule of biosurfactant showed an anionic charge and a polymeric chemical composition consisting of lipids (40.0% w/w), carbohydrates (35.2% w/w) and protein (20.3% w/w). In addition, the biosurfactant solution (1%) demonstrated its ability for an oil displacement area (ODA) of 37.36 cm2, which is quite similar to that for Triton X-100 (38.46 cm2). The stability of the reduction in the surface water tension as well as of the emulsifier index proved to be stable over a wide range of temperatures, in pH, and in salt concentration (4%–6% w/v). The biosurfactant showed an ability to reduce and increase the viscosity of hydrophobic substrates and their molecules, suggesting that it is a suitable candidate for mediated enhanced oil recovery. At the same time, these studies indicate that renewable, relatively inexpensive and easily available resources can be used for important biotechnological processes.
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