An Atlas of the Thioredoxin Fold Class Reveals the Complexity of Function-Enabling Adaptations

The group of proteins that contain a thioredoxin (Trx) fold is huge and diverse. Assessment of the variation in catalytic machinery of Trx fold proteins is essential in providing a foundation for understanding their functional diversity and predicting the function of the many uncharacterized members of the class. The proteins of the Trx fold class retain common features—including variations on a dithiol CxxC active site motif—that lead to delivery of function. We use protein similarity networks to guide an analysis of how structural and sequence motifs track with catalytic function and taxonomic categories for 4,082 representative sequences spanning the known superfamilies of the Trx fold. Domain structure in the fold class is varied and modular, with 2.8% of sequences containing more than one Trx fold domain. Most member proteins are bacterial. The fold class exhibits many modifications to the CxxC active site motif—only 56.8% of proteins have both cysteines, and no functional groupings have absolute conservation of the expected catalytic motif. Only a small fraction of Trx fold sequences have been functionally characterized. This work provides a global view of the complex distribution of domains and catalytic machinery throughout the fold class, showing that each superfamily contains remnants of the CxxC active site. The unifying context provided by this work can guide the comparison of members of different Trx fold superfamilies to gain insight about their structure-function relationships, illustrated here with the thioredoxins and peroxiredoxins

The effect of β-amyloid injection on different remembered aspects of the Morris Water Maze in rats

This experiment sought to further examine the specific memory deficits of Alzheimer\u27s disease, a disease commonly associated with memory loss. Lab rats were injected with β-amyloid, a protein known to have degenerative effects on structures within the brain that mimics Alzheimer\u27s disease, and were then required to locate a platform in a water maze task. Four rats were trained using the traditional water maze task and were then tested when the start location was manipulated or the global cues surrounding the maze were manipulated. The rats\u27 times and distances taken to locate the platform in the tests were compared to those in training. There was no significant difference between the times and distances for both manipulation tasks compared to the training. However, when the data of three out of the four rats were examined, the manipulation of global versus local cue produced a significant deficit. These data demonstrate that the rats\u27 ability to use global cues may be distorted when Alzheimer\u27s disease is mimicked

Behavioral Consequences of the Attribution of Competence in a Group Sequential Response Task

63 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1975.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Dual gradient-echo MRI of post-contraction changes in skeletal muscle blood volume and oxygenation

Analysis of post-contraction MRI signal intensity transients may allow non-invasive studies of microvascular reactivity and blood oxygenation recovery. The purpose of this study was to determine the physiological basis for post-contraction changes in short- (6 ms) and long- (46 ms) echo gradient-echo MRI signals (S(6) and S(46), respectively). Six healthy subjects were studied using dual gradient-echo MRI and near-infrared spectroscopy. S(6), S(46), total hemoglobin concentration ([THb]), and oxyhemoglobin saturation (%HbO(2)) were measured before, during, and after 1) 2 and 8 s dorsiflexion maximal voluntary contractions and 2) 5 min. of proximal arterial occlusion. Changes in S(6) and [THb] after 2 s contractions were similar to those following 8 s contractions, but changes in %HbO(2) and S(46) were greater following 8 s contractions than following 2 s contractions. [THb] and S(6) did not change during and following 5 minutes of arterial occlusion, but %HbO(2) and S(46) were both significantly depressed at similar occlusion durations. Also, distance measures indicated similarity between S(6) and [THb] and between S(46) and %HbO(2). We conclude that following brief human skeletal muscle contractions, changes in S(6) primarily reflect changes in blood volume and changes in S(46) primarily reflect changes in blood oxygenation