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Full-Text Articles in Physiology

Type Ii Protein Arginine Methyltransferase 5 (Prmt5) Is Required For Circadian Pperiod Determination In Arabidopsis Thaliana, Sunghyun Hong, Hae-Ryoung Song, Kerry Lutz, Randall A. Kerstetter, Todd P. Michael, C. Robertson Mcclung Dec 2010

Type Ii Protein Arginine Methyltransferase 5 (Prmt5) Is Required For Circadian Pperiod Determination In Arabidopsis Thaliana, Sunghyun Hong, Hae-Ryoung Song, Kerry Lutz, Randall A. Kerstetter, Todd P. Michael, C. Robertson Mcclung

Dartmouth Scholarship

Posttranslational modification is an important element in circadian clock function from cyanobacteria through plants and mammals. For example, a number of key clock components are phosphorylated and thereby marked for subsequent ubiquitination and degradation. Through forward genetic analysis we demonstrate that protein arginine methyltransferase 5 (PRMT5; At4g31120) is a critical determinant of circadian period in Arabidopsis. PRMT5 is coregulated with a set of 1,253 genes that shows alterations in phase of expression in response to entrainment to thermocycles versus photocycles in constant temperature. PRMT5 encodes a type II protein arginine methyltransferase that catalyzes the symmetric dimethylation of arginine residues (Rsme2). …


Flank Gland-Secreted Putative Chemosignals Pertaining To Photoperiod, Endocrine States, And Sociosexual Behavior In Golden Hamsters, Ying-Juan Liu, Da-Wei Wang, Lixing Sun, Jin-Hua Zhang, Jian-Xu Zhang Dec 2010

Flank Gland-Secreted Putative Chemosignals Pertaining To Photoperiod, Endocrine States, And Sociosexual Behavior In Golden Hamsters, Ying-Juan Liu, Da-Wei Wang, Lixing Sun, Jin-Hua Zhang, Jian-Xu Zhang

All Faculty Scholarship for the College of the Sciences

Behavioral studies have shown that flank glands are involved in chemical communication in golden hamsters Mesocricetus auratus but little chemical analysis has been conducted on volatiles arising from these glands. Using gas chromatography- mass spectrometry, we detected compounds from the flank glands of males, only eight of which were also produced in females. Based on these chemical data we performed a number of further experiments. By manipulating light we found that males exposed to short-photoperiods developed smaller flank glands than those exposed to long-photoperiods. Six flank gland volatiles reduced in relative abundance, which possibly coded for reproductive status of males …


Cloning Of A Chlamydomonas Reinhardtii Marker Into A Rna Interference Construct To Test Whether The Photoreceptor Chlamyrhodopsin Is Involved In Circadian Clock Resetting, Shravya Reddy Maddi Dec 2010

Cloning Of A Chlamydomonas Reinhardtii Marker Into A Rna Interference Construct To Test Whether The Photoreceptor Chlamyrhodopsin Is Involved In Circadian Clock Resetting, Shravya Reddy Maddi

Masters Theses & Specialist Projects

Chlamydomonas reinhardtii, a unicellular eukaryotic green alga, serves as a model organism to study the circadian clock in plants and animals. Rhodopsins are blue/green-light photoreceptors also found in C. reinhardtii. Chlamyrhodopsin (COP), the most abundant eyespot protein, was reported to have no role in the phototactic and photophobic responses in C. reinhardtii. Its function is yet unknown.
In the present study, we hypothesized that the function of COP is to mediate entrainment of the circadian clock by light. In order to test this hypothesis, a C. reinhardtii selection marker conferring resistance to the antibiotic paromomycin was cloned …


Kinematic Evidence For Superfast Locomotory Muscle In Two Species Of Teneriffiid Mites, Grace C. Wu, Jonathan C. Wright, Dwight L. Whitaker, Anna N. Ahn Aug 2010

Kinematic Evidence For Superfast Locomotory Muscle In Two Species Of Teneriffiid Mites, Grace C. Wu, Jonathan C. Wright, Dwight L. Whitaker, Anna N. Ahn

All HMC Faculty Publications and Research

Locomotory muscles typically operate over a narrow range of contraction frequencies, characterized by the predominant fiber types and functional roles. The highest documented frequencies in the synchronous sound-producing muscles of insects (550 Hz) and toadfish (200 Hz) far exceed the contraction frequencies observed in weight-bearing locomotory muscles, which have maximum documented frequencies below 15-30 Hz. Laws of scaling, however, predict that smaller arthropods may employ stride frequencies exceeding this range. In this study we measured running speed and stride frequency in two undescribed species of teneriffiid mites from the coastal sage scrub of southern California. Relative speeds of both species …


Avoidance Of Skeletal Muscle Atrophy In Spontaneous And Facultative Hibernators, Clark Cotton, Henry J. Harlow May 2010

Avoidance Of Skeletal Muscle Atrophy In Spontaneous And Facultative Hibernators, Clark Cotton, Henry J. Harlow

Biology Faculty Publications

Smooth and skeletal muscle changes were compared from overwintering white-tailed prairie dogs, spontaneous hibernators that undergo regular, low-temperature torpor bouts, and black-tailed prairie dogs, facultative hibernators that use sporadic, moderate-temperature torpor bouts. The objectives were to assess the abilities of these two species with dramatically different torpor patterns (1) to conserve skeletal muscle morphology, protein, and strength and (2) to use labile protein in the small intestine and liver during the winter season of reduced activity and food intake. Mass and protein concentration of the extensor digitorum longus (EDL), soleus, liver, and small intestine, as well as skeletal muscle strength …


Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifsh Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeff Duerr, Jason E. Podrabsky Jan 2010

Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifsh Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeff Duerr, Jason E. Podrabsky

Faculty Publications - Department of Biological & Molecular Science

Diapausing embryos of the annual killiWsh Austrofundulus limnaeus have the highest reported anoxia tolerance of any vertebrate and previous studies indicate modified mitochondrial physiology likely supports anoxic metabolism. Functional mitochondria isolated from diapausing and developing embryos of the annual killifish exhibited VO2, respiratory control ratios (RCR), and P:O ratios consistent with those obtained from other ectothermic vertebrate species. Reduced oxygen consumption associated with dormancy in whole animal respiration rates are correlated with maximal respiration rates of mitochondria isolated from diapausing versus developing embryos. P:O ratios for developing embryos were similar to those obtained from adult liver, but were diminished in …


Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeffrey M. Duerr, Jason E. Podrabsky Jan 2010

Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeffrey M. Duerr, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Diapausing embryos of the annual killifish Austrofundulus limnaeus have the highest reported anoxia tolerance of any vertebrate and previous studies indicate modified mitochondrial physiology likely supports anoxic metabolism. Functional mitochondria isolated from diapausing and developing embryos of the annual killifish exhibited VO2, respiratory control ratios (RCR), and P:O ratios consistent with those obtained from other ectothermic vertebrate species. Reduced oxygen consumption associated with dormancy in whole animal respiration rates are correlated with maximal respiration rates of mitochondria isolated from diapausing versus developing embryos. P:O ratios for developing embryos were similar to those obtained from adult liver, but were diminished in …