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Full-Text Articles in Biology

Cryopreservation Of Spin-Dried Mammalian Cells, Nilay Chakraborty, Michael A. Menze, Jason Malsam, Alptekin Aksan, Steven C. Hand, Mehmet Toner Sep 2011

Cryopreservation Of Spin-Dried Mammalian Cells, Nilay Chakraborty, Michael A. Menze, Jason Malsam, Alptekin Aksan, Steven C. Hand, Mehmet Toner

Michael Menze

This study reports an alternative approach to achieve vitrification where cells are pre-desiccated prior to cooling to cryogenic temperatures for storage. Chinese Hamster Ovary (CHO) cells suspended in a trehalose solution were rapidly and uniformly desiccated to a low moisture content (<0.12 g of water per g of dry weight) using a spin-drying technique. Trehalose was also introduced into the cells using a high-capacity trehalose transporter (TRET1). Fourier Transform Infrared Spectroscopy (FTIR) was used to examine the uniformity of water concentration distribution in the spin-dried samples. 62% of the cells were shown to survive spin-drying in the presence of trehalose following immediate rehydration. The spin-dried samples were stored in liquid nitrogen (LN2) at a vitrified state. It was shown that following re-warming to room temperature and re-hydration with a fully complemented cell culture medium, 51% of the spin-dried and vitrified cells survived and demonstrated normal growth characteristics. Spin-drying is a novel strategy that can be used to improve cryopreservation outcome by promoting rapid vitrification.


Metabolic Restructuring During Energy-Limited States: Insights From Artemia Franciscana Embryos And Other Animals, Steven C. Hand, Michael A. Menze, Apu Borcar, Yuvraj Patil, Joseph A. Covi, Julie A. Reynolds, Mehmet Toner Jan 2011

Metabolic Restructuring During Energy-Limited States: Insights From Artemia Franciscana Embryos And Other Animals, Steven C. Hand, Michael A. Menze, Apu Borcar, Yuvraj Patil, Joseph A. Covi, Julie A. Reynolds, Mehmet Toner

Michael Menze

Many life history stages of animals that experience environmental insults enter developmental arrested states that are characterized by reduced cellular proliferation, with or without a concurrent reduction in overall metabolism. In the case of the most profound metabolic arrest reported in invertebrates, i.e., anaerobic quiescence in Artemia franciscana embryos, acidification of the intracellular milieu is a major factor governing catabolic and anabolic downregulation. Release of ion gradients from intracellular compartments is the source for approximately 50% of the proton equivalents needed for the 1.5 unit acidification that is observed. Recovery from the metabolic arrest requires re-sequestration of the protons with …


Lea Proteins During Water Stress: Not Just For Plants Anymore, Steven C. Hand, Michael A. Menze, Mehmet Toner, Leaf Boswell, Daniel Moore Jan 2011

Lea Proteins During Water Stress: Not Just For Plants Anymore, Steven C. Hand, Michael A. Menze, Mehmet Toner, Leaf Boswell, Daniel Moore

Michael Menze

Late embryogenesis abundant (LEA) proteins are extremely hydrophilic proteins that were first identified in land plants. Intracellular accumulation is tightly correlated with acquisition of desiccation tolerance, and data support their capacity to stabilize other proteins and membranes during drying, especially in the presence of sugars like trehalose. Exciting reports now show LEA proteins are not restricted to plants; multiple forms are expressed in desiccation-tolerant animals from at least four phyla. We evaluate here the expression, subcellular localization, biochemical properties and potential functions of LEA proteins in animal species during water stress. LEA proteins are intrinsically unstructured in aqueous solution, but …