Previous work from the laboratory has shown by immunochemical assay that vitamin A deficiency cau... more Previous work from the laboratory has shown by immunochemical assay that vitamin A deficiency caused a greatly increased plasma level of fibronectin (FN), a high molecular-weight glycoprotein involved in cell adhesion and found in plasma. The authors determined that primary hepatocytes of vitamin A-deficient rats secreted more FN into the medium than those of pair-fed controls, synthesized more FN (as
Recent work from our laboratory (Kim and Wolf, J Biol Chem 262:365-371, 1987) has shown increased... more Recent work from our laboratory (Kim and Wolf, J Biol Chem 262:365-371, 1987) has shown increased uptake of labeled amino acids into fibronectin (FN), increased net synthesis of FN and increased levels of FN-mRNA in primary cultures of hepatocytes from vitamin A-deficient rats compared to controls. We now find, surprisingly, decreased uptake of labeled sugars into the oligosaccharide chains of FN from vitamin A-deficient hepatocytes. This decrease could be reversed by added retinoic acid at physiological concentration. At the same time, FN from deficient hepatocytes (-A.FN) was more susceptible to proteolytic degradation. Decreased uptake of the core sugar mannose into -A.FN was similar to that of glucosamine, yet the percent of label in sialic acid was the same as in + A.FN, suggesting a smaller number of oligosaccharide chains per molecule of -A.FN. Upon enzymatic removal of oligosaccharide and labeling with sodium borotritide, it was found that both -A.FN and +A.FN had biantennary oligosaccharide structures. Selective enzymatic removal of sialic acid showed that +A.FN had both sialic acids in an alpha 2----3 linkage, whereas -A.FN apparently had one alpha 2----3 and one alpha 2----6-linked sialic acid. The borotritide experiments allowed us to calculate that +A.FN appeared to have 5 oligosaccharide chains per FN monomer, whereas the -A.FN showed only 4 chains. These results would account for the decreased glycosylation and increased susceptibility to proteolysis of the -A.FN. We conclude that vitamin A controls both the rate of synthesis of the polypeptide chain of FN via its mRNA, as well as the rate of its glycosylation.
I. INTRODUCTION There are multiple pathways of intracellular proteolysis in eukaryotic cells (Dic... more I. INTRODUCTION There are multiple pathways of intracellular proteolysis in eukaryotic cells (Dice 1987; Hershko and Ciechanover 1992; Olson et al. 1992). The best studied cytosolic pathway is dependent on ATP and ubiquitin and is responsible for the degradation of many abnormal proteins as well as many short-lived normal proteins (Rechsteiner 1991; Hershko and Ciechanover 1992). Other cytosolic proteolytic pathways are independent of ubiquitin, and still others are not cytosolic but are contained within organelles such as the endoplasmic reticulum and mitochondrion (Olson et al. 1992). It is also well established that lysosomes have an important role in overall proteolysis (Mortimore 1987), and lysosomes appear to be able to internalize intracellular proteins in a variety of ways. For example, degradation of many plasma membrane proteins, as well as certain other intracellular membrane proteins, is through endocytosis and delivery to lysosomes (Fig. 1) (Hare 1990). In well-nourishe...
The Space Station Biological Research Project is developing habitats to accommodate long duration... more The Space Station Biological Research Project is developing habitats to accommodate long duration experiments for a variety of research organisms on the International Space Station. An Insect Habitat will house Drosophila melanogaster, and in the future will ...
... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks,... more ... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks, M.; Ceballos, M.; Taylor, L.; Bell, B ... in astrobiology by the Minority Serving Institutions include the first direct detection of an extrasolar planet and a MSI graduate, LaTasha Taylor, featured in ...
Gravitational and space biology bulletin : publication of the American Society for Gravitational and Space Biology, 2005
To support the study of the effects of microgravity on biological systems, our group is developin... more To support the study of the effects of microgravity on biological systems, our group is developing and testing methods that allow the cultivation of C. elegans and S. cerevisiae in microgravity. Our aim is to develop the experimental means by which investigators may conduct peer reviewed biological experiments with C. elegans or S. cerevisiae in microgravity. Our protocols are aimed at enabling investigators to grow these organisms for extended periods during which samples may be sub-cultured, collected, preserved, frozen, and/or returned to earth for analysis. Data presented include characterization of the growth phenotype of these organisms in liquid medium in OptiCells(TM) (Biocrystal, LTD).
Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2004
The CCU and Incubator are habitats under development by SSBRP for gravitational biology research ... more The CCU and Incubator are habitats under development by SSBRP for gravitational biology research on ISS. They will accommodate multiple specimen types and reside in either Habitat Holding Racks, or the Centrifuge Rotor, which provides selectable gravity levels of up to 2 g. The CCU can support multiple Cell Specimen Chambers, CSCs (18, 9 or 6 CSCs; 3, 10 or 30 mL in volume, respectively). CSCs are temperature controlled from 4-39 degrees C, with heat shock to 45 degrees C. CCU provides automated nutrient supply, magnetic stirring, pH/O2 monitoring, gas supply, specimen lighting, and video microscopy. Sixty sample containers holding up to 2 mL each, stored at 4-39 degrees C, are available for automated cell sampling, subculture, and injection of additives and fixatives. CSCs, sample containers, and fresh/spent media bags are crew-replaceable for long-term experiments. The Incubator provides a 4-45 degrees C controlled environment for life science experiments or storage of experimenta...
2001 Conference and Exhibit on International Space Station Utilization, 2001
The Space Station Biological Research Project is developing habitats to accommodate long duration... more The Space Station Biological Research Project is developing habitats to accommodate long duration experiments for a variety of research organisms on the International Space Station. An Insect Habitat will house Drosophila melanogaster, and in the future will ...
... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks,... more ... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks, M.; Ceballos, M.; Taylor, L.; Bell, B ... in astrobiology by the Minority Serving Institutions include the first direct detection of an extrasolar planet and a MSI graduate, LaTasha Taylor, featured in ...
Previous work from the laboratory has shown by immunochemical assay that vitamin A deficiency cau... more Previous work from the laboratory has shown by immunochemical assay that vitamin A deficiency caused a greatly increased plasma level of fibronectin (FN), a high molecular-weight glycoprotein involved in cell adhesion and found in plasma. The authors determined that primary hepatocytes of vitamin A-deficient rats secreted more FN into the medium than those of pair-fed controls, synthesized more FN (as
Recent work from our laboratory (Kim and Wolf, J Biol Chem 262:365-371, 1987) has shown increased... more Recent work from our laboratory (Kim and Wolf, J Biol Chem 262:365-371, 1987) has shown increased uptake of labeled amino acids into fibronectin (FN), increased net synthesis of FN and increased levels of FN-mRNA in primary cultures of hepatocytes from vitamin A-deficient rats compared to controls. We now find, surprisingly, decreased uptake of labeled sugars into the oligosaccharide chains of FN from vitamin A-deficient hepatocytes. This decrease could be reversed by added retinoic acid at physiological concentration. At the same time, FN from deficient hepatocytes (-A.FN) was more susceptible to proteolytic degradation. Decreased uptake of the core sugar mannose into -A.FN was similar to that of glucosamine, yet the percent of label in sialic acid was the same as in + A.FN, suggesting a smaller number of oligosaccharide chains per molecule of -A.FN. Upon enzymatic removal of oligosaccharide and labeling with sodium borotritide, it was found that both -A.FN and +A.FN had biantennary oligosaccharide structures. Selective enzymatic removal of sialic acid showed that +A.FN had both sialic acids in an alpha 2----3 linkage, whereas -A.FN apparently had one alpha 2----3 and one alpha 2----6-linked sialic acid. The borotritide experiments allowed us to calculate that +A.FN appeared to have 5 oligosaccharide chains per FN monomer, whereas the -A.FN showed only 4 chains. These results would account for the decreased glycosylation and increased susceptibility to proteolysis of the -A.FN. We conclude that vitamin A controls both the rate of synthesis of the polypeptide chain of FN via its mRNA, as well as the rate of its glycosylation.
I. INTRODUCTION There are multiple pathways of intracellular proteolysis in eukaryotic cells (Dic... more I. INTRODUCTION There are multiple pathways of intracellular proteolysis in eukaryotic cells (Dice 1987; Hershko and Ciechanover 1992; Olson et al. 1992). The best studied cytosolic pathway is dependent on ATP and ubiquitin and is responsible for the degradation of many abnormal proteins as well as many short-lived normal proteins (Rechsteiner 1991; Hershko and Ciechanover 1992). Other cytosolic proteolytic pathways are independent of ubiquitin, and still others are not cytosolic but are contained within organelles such as the endoplasmic reticulum and mitochondrion (Olson et al. 1992). It is also well established that lysosomes have an important role in overall proteolysis (Mortimore 1987), and lysosomes appear to be able to internalize intracellular proteins in a variety of ways. For example, degradation of many plasma membrane proteins, as well as certain other intracellular membrane proteins, is through endocytosis and delivery to lysosomes (Fig. 1) (Hare 1990). In well-nourishe...
The Space Station Biological Research Project is developing habitats to accommodate long duration... more The Space Station Biological Research Project is developing habitats to accommodate long duration experiments for a variety of research organisms on the International Space Station. An Insect Habitat will house Drosophila melanogaster, and in the future will ...
... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks,... more ... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks, M.; Ceballos, M.; Taylor, L.; Bell, B ... in astrobiology by the Minority Serving Institutions include the first direct detection of an extrasolar planet and a MSI graduate, LaTasha Taylor, featured in ...
Gravitational and space biology bulletin : publication of the American Society for Gravitational and Space Biology, 2005
To support the study of the effects of microgravity on biological systems, our group is developin... more To support the study of the effects of microgravity on biological systems, our group is developing and testing methods that allow the cultivation of C. elegans and S. cerevisiae in microgravity. Our aim is to develop the experimental means by which investigators may conduct peer reviewed biological experiments with C. elegans or S. cerevisiae in microgravity. Our protocols are aimed at enabling investigators to grow these organisms for extended periods during which samples may be sub-cultured, collected, preserved, frozen, and/or returned to earth for analysis. Data presented include characterization of the growth phenotype of these organisms in liquid medium in OptiCells(TM) (Biocrystal, LTD).
Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 2004
The CCU and Incubator are habitats under development by SSBRP for gravitational biology research ... more The CCU and Incubator are habitats under development by SSBRP for gravitational biology research on ISS. They will accommodate multiple specimen types and reside in either Habitat Holding Racks, or the Centrifuge Rotor, which provides selectable gravity levels of up to 2 g. The CCU can support multiple Cell Specimen Chambers, CSCs (18, 9 or 6 CSCs; 3, 10 or 30 mL in volume, respectively). CSCs are temperature controlled from 4-39 degrees C, with heat shock to 45 degrees C. CCU provides automated nutrient supply, magnetic stirring, pH/O2 monitoring, gas supply, specimen lighting, and video microscopy. Sixty sample containers holding up to 2 mL each, stored at 4-39 degrees C, are available for automated cell sampling, subculture, and injection of additives and fixatives. CSCs, sample containers, and fresh/spent media bags are crew-replaceable for long-term experiments. The Incubator provides a 4-45 degrees C controlled environment for life science experiments or storage of experimenta...
2001 Conference and Exhibit on International Space Station Utilization, 2001
The Space Station Biological Research Project is developing habitats to accommodate long duration... more The Space Station Biological Research Project is developing habitats to accommodate long duration experiments for a variety of research organisms on the International Space Station. An Insect Habitat will house Drosophila melanogaster, and in the future will ...
... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks,... more ... Authors: Gary, T.; Butler, J.; Arino de La Rubia, L.; Myles, EL; Bradford, K.; Kirven-Brooks, M.; Ceballos, M.; Taylor, L.; Bell, B ... in astrobiology by the Minority Serving Institutions include the first direct detection of an extrasolar planet and a MSI graduate, LaTasha Taylor, featured in ...
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Papers by Melissa Kirven-Brooks