Investigation of the function of branching enzymes I, IIa, and IIb in the determination of amylopectin structure and regulation of starch biosynthesis

Starch is one of the most abundant carbohydrates on earth serving vital roles as the primary energy reserve of plants, a significant source of calories in the human diet, and a renewable resource for other industrial applications. The multiplicity of starch biosynthetic enzymes is evolutionarily conserved in plants suggesting their functions are essential in starch biosynthesis. The overall goal of this research is to determine the specific molecular functions of the multiple starch branching enzyme (BE) isoforms in maize.;This dissertation first addresses what, if any, are the differences in enzymatic properties of BEIIa and BEIIb. Two polyclonal antisera were produced, alphaBEI and alphaBEIIab which specifically identify BEI and both BEII isoforms, respectively. Chromatographic purification techniques separated native BEIIa or BEIIb from the other two branching enzymes. The capacities to modify the structure of amylose were compared between native BEIIa and BEIIb and recombinant BEIIa (rIIa). The evolutionary conservation of BEIIa and BEIIb is not accounted for by their enzymatic differences. Differences in the glucan chain length distribution created by native BEIIa and rIIa suggest that in vivo there are factors affecting the activity of BEs.;This dissertation next addresses are branching enzymes involved in multi-subunit complexes (MSCs)? This research provides direct evidence BEIIa and SSI interact with each other in MSC and that SSIII may be a component of the MSCs. Indirect evidence from GPC analysis of BEIIb and multiple electrophoretic mobility forms of BEI suggests that they may be involved in MSCs. Pleiotropic effects in branching enzyme mutants on starch synthase (SS) activity revealed at least three SS band activities are affected when BEIIa was mutated. Further research is needed to investigate the functional significance of the complexes involving BEIIa, SSI and possibly SSIII.;This dissertation addresses what branching enzyme isoforms exist in leaves as compared to endosperm. The same BEI polypeptide present in maize endosperm was found to be present in maize leaves. Leaf BEI was found to be similar to endosperm BEI in predicted molecular weight, approximately 80 kDa, in molecule size, a monomeric protein, and also possesses multiple electrophoretic mobility forms

Southeastern Association of Law Libraries Annual Meeting

The 2009 SEAALL Annual Meeting was held in Athens Georgia, April 16-18, 2009

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Southeastern Association of Law Libraries Annual Meeting

The 2009 SEAALL Annual Meeting was held in Athens Georgia, April 16-18, 2009