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- Anhydrobiosis (Life without Water) (3)
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Articles 1 - 8 of 8
Full-Text Articles in Biology
Seasonal Variation In Mitochondrial Bioenergetics Of The Bluegill Sunfish, Lepomis Macrochirus, From A Shallow Midwest River, Derick Isaac Lamptey
Seasonal Variation In Mitochondrial Bioenergetics Of The Bluegill Sunfish, Lepomis Macrochirus, From A Shallow Midwest River, Derick Isaac Lamptey
Masters Theses
As average global temperature increase, the frequency and magnitude of extreme temperatures in shallow aquatic ecosystems are more ubiquitous. In order to understand how these changing thermal regimes affect aquatic ectotherms, it is essential to develop studies evaluating the response of ectotherms to seasonal fluctuating thermal regimes. Previous studies on fluctuating temperature regimes have reported an increased physiological stress leading to morphological, behavioral and biochemical adaptations. From the latter, the adaptive capacity and seasonal performance associated with optimal function of the oxidative phosphorylation system (OXPHOS) are key for species persistence. However, studies on this matter are scarce. This study explores …
Tradeoffs Of Warm Adaptation In Aquatic Ectotherms: Live Fast, Die Young?, Eloy Martinez, Anthony Porreca, Robert Colombo, Michael Menze
Tradeoffs Of Warm Adaptation In Aquatic Ectotherms: Live Fast, Die Young?, Eloy Martinez, Anthony Porreca, Robert Colombo, Michael Menze
Faculty Research & Creative Activity
In the face of a changing climate, questions regarding sub-lethal effects of elevated habitat temperature on the physiology of ectotherms remain unanswered. In particular, long-term responses of ectotherms to the warming trend in tropical regions are unknown, and understudied due to the difficulties in specimen and community traceability. In freshwater lakes employed as cooling reservoirs for power plants, increased physiological stress from high water temperature can potentially alter the community structure of fishes. We employ this highly tractable system to assess how thermal regimes can alter the physiology and ecology of aquatic species. We documented a significantly reduced lifespan, growth …
Cryopreservation Of Hepatocyte (Hepg2) Cell Monolayers: Impact Of Trehalose, Blake Stokich, Quinn Osgood, David Grimm, Shhyam Moorthy, Nilay Chakraborty, Michael A. Menze
Cryopreservation Of Hepatocyte (Hepg2) Cell Monolayers: Impact Of Trehalose, Blake Stokich, Quinn Osgood, David Grimm, Shhyam Moorthy, Nilay Chakraborty, Michael A. Menze
Faculty Research & Creative Activity
A simple method to cryogenically preserve hepatocyte monolayers is currently not available but such a technique would facilitate numerous applications in the field of biomedical engineering, cell line development, and drug screening. We investigated the effect of trehalose and dimethyl sulfoxide (Me2SO) in cryopreservation of human hepatocellular carcinoma (HepG2) cells in suspension and monolayer formats. HepG2 cell monolayers were incubated for 24 h at varying concentrations of trehalose (50–150 mM) prior to cryopreservation to identify the optimum concentration for such preincubation. When trehalose alone was used as the cryoprotective agent (CPA), cells in monolayer format did not survive freezing while …
Improved Tolerance To Salt And Water Stress In Drosophila Melanogaster Cells Conferred By Late Embryogenesis Abundant Protein, Matthew R. Marunde, Dilini A. Samarajeewa, John Anderson, Shumin Li, Steven C. Hand, Michael A. Menze
Improved Tolerance To Salt And Water Stress In Drosophila Melanogaster Cells Conferred By Late Embryogenesis Abundant Protein, Matthew R. Marunde, Dilini A. Samarajeewa, John Anderson, Shumin Li, Steven C. Hand, Michael A. Menze
Faculty Research & Creative Activity
Mechanisms that govern anhydrobiosis involve the accumulation of highly hydrophilic macromolecules, such as late embryogenesis abundant (LEA) proteins. Group 1 LEA proteins comprised of 181 (AfLEA1.1) and 197 (AfLEA1.3) amino acids were cloned from embryos of Artemia franciscana and expressed in Drosophila melanogaster cells (Kc167). Confocal microscopy revealed a construct composed of green fluorescence protein (GFP) and AfLEA1.3 accumulates in the mitochondria (AfLEA1.3-GFP), while AfLEA1.1-GFP was found in the cytoplasm. In the presence of mixed substrates, oxygen consumption was statistically identical for permeabilized Kc167 control and Kc167-AfLEA1.3 cells. Acute titrations of permeabilized cells with NaCl up to 500 mM led …
Diapause And Anhydrobiosis In Embryos Of Artemia Franciscana: Metabolic Depression, Lea Proteins And Water Stress, Steven C. Handel, Yuvraj Patil, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Leaf C. Boswell, Daniel Moore, Mehmet Toner
Diapause And Anhydrobiosis In Embryos Of Artemia Franciscana: Metabolic Depression, Lea Proteins And Water Stress, Steven C. Handel, Yuvraj Patil, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Leaf C. Boswell, Daniel Moore, Mehmet Toner
Faculty Research & Creative Activity
Metabolic depression is typically correlated with extended survival of environmental challenge and energy-limitation in early life stages of various invertebrates and vertebrates. Diapause is an ontogenetically-programmed reduction of development and often metabolism seen in many invertebrates. When embryos of Artemia franciscana enter the state of diapause, the overall metabolic depression is estimated to be greater than 99%. These embryos also contain trehalose and express multiple isoforms of Late Embryogenesis Abundant (LEA) proteins, constituents often present in a number of such anhydrobiotic animals. The mRNA levels for LEA proteins are highest in diapause and post-diapause embryos that possess desiccation tolerance, but …
Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand
Late Embryogenesis Abundant Proteins Protect Human Hepatoma Cells During Acute Desiccation, Shumin Li, Nilay Chakraborty, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand
Faculty Research & Creative Activity
Expression of late embryogenesis abundant (LEA) proteins is highly correlated with desiccation tolerance in anhydrobiotic animals, selected land plants, and bacteria. Genes encoding two LEA proteins, one localized to the cytoplasm/nucleus (AfrLEA2) and one targeted to mitochondria (AfrLEA3m), were stably transfected into human HepG2 cells. A trehalose transporterwas used for intracellular loading of this disaccharide. Cellswere rapidly and uniformly desiccated to low water content (<0.12 g H2O/g dry weight) with a recently developed spin-drying technique. Immediately on rehydration, control cells without LEA proteins or trehalose exhibited 0% membrane integrity, comparedwith 98% in cells loaded with trehalose and expressing AfrLEA2 or AfrLEA3m; surprisingly, AfrLEA3m without trehalose conferred 94% protection. Cell proliferation across 7 d showed an 18-fold increase for cells dried with AfrLEA3m and trehalose, compared with 27-fold for nondried controls. LEA proteins dramatically enhance desiccation tolerance in mammalian cells and offer the opportunity for engineering biostability in the dried state.
Metabolic Preconditioning Of Mammalian Cells: Mimetic Agents For Hypoxia Lack Fidelity In Promoting Phosphorylation Of Pyruvate Dehydrogenase, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand
Metabolic Preconditioning Of Mammalian Cells: Mimetic Agents For Hypoxia Lack Fidelity In Promoting Phosphorylation Of Pyruvate Dehydrogenase, Apurva Borcar, Michael A. Menze, Mehmet Toner, Steven C. Hand
Faculty Research & Creative Activity
Induction of HIF-1α by oxygen limitation promotes increased phosphorylation and catalytic depression of mitochondrial pyruvate dehydrogenase (PDH) and an enhanced glycolytic poise in cells. Cobalt chloride and desferrioxamine are widely used as mimics for hypoxia because they increase the levels of HIF-1α. We evaluated the ability of these agents to elicit selected physiological responses to hypoxia as a means to metabolically precondition mammalian cells, but without the detrimental effects of hypoxia. We show that, while CoCl2 does increase HIF-1α in a dose-dependent manner, it unexpectedly and strikingly decreases PDH phosphorylation at E1α sites 1, 2, and 3 (Ser293, Ser300, and …
Long-Term Survival Of Anoxia Despite Rapid Atp Decline In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Jason E. Podrabsky, Michael A. Menze, Steven C. Hand
Long-Term Survival Of Anoxia Despite Rapid Atp Decline In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Jason E. Podrabsky, Michael A. Menze, Steven C. Hand
Faculty Research & Creative Activity
Embryos of the annual killifish Austrofundulus limnaeus can survive for months in the complete absence of oxygen. Survival of anoxia is associated with entry into a state of metabolic dormancy known as diapause. However, extreme tolerance of anoxia is retained for several days of post-diapause development. Rates of heat dissipation in diapause II and 4 days post-diapause II embryos were measured under aerobic conditions and during the transition into anoxia. Phosphorylated adenylate compounds were quantified in embryos during entry into anoxia and after 12 hr of aerobic recovery. Rates of heat dissipation were not affected by exposure to anoxia in …