A role for mechanosensitive channels in chloroplast and bacterial fission.

The division site in both chloroplasts and bacteria is established by the medial placement of the FtsZ ring, a process that is in part regulated by the evolutionarily conserved components of the Min system. We recently showed that mechanosensitive ion channels influence FtsZ ring assembly in both Arabidopsis thaliana chloroplasts and in Escherichia coli; in chloroplasts they do so through the same genetic pathway as the Min system. Here we describe the effect of heterologous expression of the Arabidopsis MS channel homolog MSL2 on FtsZ ring placement in E. coli. We also discuss possible molecular mechanisms by which MS channels might influence chloroplast or bacterial division

Comparison of objective and subjective evaluations of tenderness of beef

This bulletin is a report on School of Home Economics project 349, 'Improving the Acceptability of Meat'--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 15-16)

RNA Sequencing Analysis of the msl2msl3, crl, and ggps1 Mutants Indicates that Diverse Sources of Plastid Dysfunction Do Not Alter Leaf Morphology Through a Common Signaling Pathway

Determining whether individual genes function in the same or in different pathways is an important aspect of genetic analysis. As an alternative to the construction of higher-order mutants, we used contemporary expression profiling methods to perform pathway analysis on several Arabidopsis thaliana mutants, including the mscS-like (msl)2msl3 double mutant. MSL2 and MSL3 are implicated in plastid ion homeostasis, and msl2msl3 double mutants exhibit leaves with a lobed periphery, a rumpled surface, and disturbed mesophyll cell organization. Similar developmental phenotypes are also observed in other mutants with defects in a range of other chloroplast or mitochondrial functions, including biogenesis, gene expression, and metabolism. We wished to test the hypothesis that the common leaf morphology phenotypes of these mutants are the result of a characteristic nuclear expression pattern that is generated in response to organelle dysfunction. RNA-Sequencing was performed on aerial tissue of msl2msl3 geranylgeranyl diphosphate synthase 1 (ggps1), and crumpled leaf (crl) mutants. While large groups of co-expressed genes were identified in pairwise comparisons between genotypes, we were only able to identify a small set of genes that showed similar expression profiles in all three genotypes. Subsequent comparison to the previously published gene expression profiles of two other mutants, yellow variegated 2 (var2) and scabra3 (sca3), failed to reveal a common pattern of gene expression associated with superficially similar leaf morphology defects. Nor did we observe overlap between genes differentially expressed in msl2msl3, crl, and ggps1 and a previously identified retrograde core response module. These data suggest that a common retrograde signaling pathway initiated by organelle dysfunction either does not exist in these mutants or cannot be identified through transcriptomic methods. Instead, the leaf developmental defects observed in these mutants may be achieved through a number of independent pathways

The Joint Effects of Interactions between Data Display and Task Variables on Task Performance

Recent studies of data presentation focus on dependencies that exist between data displays and specific tasks. We propose that joint interactions between data display and key task variables contribute to these dependencies. This paper reports the findings of an experiment which investigates the effects of interactions between display fonnat and two task variables: question type and question complexity. We find that both interactions significantly influence task performance

Two mechanosensitive channel homologs influence division ring placement in Arabidopsis chloroplasts

Chloroplasts must divide repeatedly to maintain their population during plant growth and development. A number of proteins required for chloroplast division have been identified, and the functional relationships between them are beginning to be elucidated. In both chloroplasts and bacteria, the future site of division is specified by placement of the Filamentous temperature sensitive Z (FtsZ) ring, and the Min system serves to restrict FtsZ ring formation to mid-chloroplast or mid-cell. How the Min system is regulated in response to environmental and developmental factors is largely unstudied. Here, we investigated the role in chloroplast division played by two Arabidopsis thaliana homologs of the bacterial mechanosensitive (MS) channel MscS: MscS-Like 2 (MSL2) and MSL3. Immunofluorescence microscopy and live imaging approaches demonstrated that msl2 msl3 double mutants have enlarged chloroplasts containing multiple FtsZ rings. Genetic analyses indicate that MSL2, MSL3, and components of the Min system function in the same pathway to regulate chloroplast size and FtsZ ring formation. In addition, an Escherichia coli strain lacking MS channels also showed aberrant FtsZ ring assembly. These results establish MS channels as components of the chloroplast division machinery and suggest that their role is evolutionarily conserved

Plastid osmotic stress influences cell differentiation at the plant shoot apex

The balance between proliferation and differentiation in the plant shoot apical meristem is controlled by regulatory loops involving the phytohormone cytokinin and stem cell identity genes. Concurrently, cellular differentiation in the developing shoot is coordinated with the environmental and developmental status of plastids within those cells. Here, we employ an Arabidopsis thaliana mutant exhibiting constitutive plastid osmotic stress to investigate the molecular and genetic pathways connecting plastid osmotic stress with cell differentiation at the shoot apex. msl2 msl3 mutants exhibit dramatically enlarged and deformed plastids in the shoot apical meristem, and develop a mass of callus tissue at the shoot apex. Callus production in this mutant requires the cytokinin receptor AHK2 and is characterized by increased cytokinin levels, downregulation of cytokinin signaling inhibitors ARR7 and ARR15, and induction of the stem cell identity gene WUSCHEL. Furthermore, plastid stress-induced apical callus production requires elevated plastidic reactive oxygen species, ABA biosynthesis, the retrograde signaling protein GUN1, and ABI4. These results are consistent with a model wherein the cytokinin/WUS pathway and retrograde signaling control cell differentiation at the shoot apex

Reduced selenium concentrations and glutathione peroxidase activity in preeclamptic pregnancies

Preeclampsia is a pregnancy-specific condition affecting 2-7% of women and a leading cause of perinatal and maternal morbidity and mortality. Preeclampsia may also predispose the fetus to increased risks of adult cardiovascular disease. Selenium, acting through the selenoprotein glutathione peroxidases, has critical roles in regulating antioxidant status. Recent reports implicate poor maternal selenium status as a nutritional factor predisposing the mother to preeclampsia but the fetus and placenta have not been studied in tandem. Measurement of selenium concentrations, expression and activity levels of glutathione peroxidase and markers of oxidative stress were performed on maternal and umbilical venous blood samples or the placenta from 27 normal pregnant, 25 preeclamptic and 22 healthy age-matched non-pregnant women. The results of this study revealed highly significant reductions in serum selenium concentrations and plasma glutathione peroxidase activity in pregnancy per se compared to non-pregnant controls. Moreover, these levels were further decreased in the preeclamptic mothers and babies compared to normal pregnancies. Umbilical venous selenium was particularly low (42.1±11.8 and 29.0 ± 9.9 mug/L; mean ±s.d.; P<0.05). Both mother and baby had significantly increased levels of markers for oxidative stress in the preeclamptic group. The placental glutathione peroxidase activity and immunohistochemical staining were also reduced in the preeclampsia placentae. Oxidative stress associated with preeclampsia may be a consequence of reduced antioxidant defence pathways specifically involving glutathione peroxidases, perhaps linked to reduced selenium availability. Reduced glutathione peroxidases could be associated with increased generation of toxic lipid peroxides contributing to the endothelial dysfunction and hypertension of preeclampsia

Nurses\u27 Alumnae Association Bulletin, June 1964

President\u27s Message Officers and Committee Chairmen Financial Report Hospital and School of Nursing Report Student Activities Jefferson Expansion Program Resume of Alumnae Meetings Staff Nurses Private Duty Social Committee Reports Program Scholarship Bulletin Committee Report Annual Luncheon Notes Membership and Dues Units in Jefferson Expansion Program Center Annual Giving Drive 1963 Report of Ways and Means Committee Jefferson Building Fund Contributions Annual Giving Contributions 1964 Jefferson Building Fund Report Help the Building Fund Committee! Vital Statistics Class News Notice

Albumin enhanced morphometric image analysis in CLL.

BACKGROUND: The heterogeneity of lymphocytes from patients with chronic lymphocytic leukemia (CLL) and blood film artifacts make morphologic subclassification of this disease difficult. METHODS: We reviewed paired blood films prepared from ethylene-diamine-tetraacetic acid (ETDA) samples with and without bovine serum albumin (BSA) from 82 CLL patients. Group 1 adhered to NCCLS specifications for the preparations of EDTA blood films. Group 2 consisted of blood films containing EDTA and a 1:12 dilution of 22% BSA. Eight patients were selected for digital photomicroscopy and statistical analysis. Approximately 100 lymphocytes from each slide were digitally captured. RESULTS: The mean cell area +/- standard error was 127.8 microm(2) +/- 1.42 for (n = 793) for group 1 versus 100.7 microm(2) +/- 1.39 (n = 831) for group 2. The nuclear area was 88.9 microm(2) +/- 0.85 for group 1 versus 76.4 microm(2) +/- 0.83 for group 2. For the nuclear transmittance, the values were 97.6 +/- 0.85 for group 1 and 104.1 +/- 0.83 for group 2. The nuclear:cytoplasmic ratios were 0.71 +/- 0.003 for group 1 and 0.78 +/- 0.003 for group 2. All differences were statistically significant (P \u3c 0.001). CONCLUSIONS: BSA addition results in the reduction of atypical lymphocytes and a decrease in smudge cells. BSA also decreases the lymphocyte area and nuclear area, whereas nuclear transmittance and nuclear:cytoplasmic ratio are increased. A standardized method of slide preparation would allow accurate interlaboratory comparison. The use of BSA may permit better implementation of the blood film-based subclassification of CLL and lead to a better correlation of morphology with cytogenetics and immunophenotyping. Published 2003 Wiley-Liss, Inc

Acetylseco hemicholinium-3, a new choline acetyltransferase inhibitor useful in neuropharmacological studies

Described are the synthesis and some aspects of the pharmacology of acetylseco hemicholinium-3 (acetylseco HC-3), the acetylated open ring analogue of hemicholinium-3 (HC-3). The effects of both compounds were determined in vivo on rat brain acetylcholine (ACh), 14C-eholine (14C-Ch) incorporation into 14C-acetylcholine (14C-ACh) and on one way jump box avoidance and escape behavior in naive and trained rats. In addition, the in vitro effects of both drugs were determined on choline acetyltransferase activity (ChAc) in rat brain.When given intraventricularly in doses of 1-20 [mu]g both compounds reduced total ACh content in the brain to a maximum of 50% of normal in 30-60 min. In doses of 20 [mu]g intraventricularly, both drugs also reduced 14C-Ch incorporation into 14C-ACh by 84.5% for acetylseco HC-3 and by 52% for HC-3.The in vivo changes of ACh in the brain were correlated with the behavioral deficits induced in one way shuttle box acquisition and retention. In doses of 20 [mu]g total intraventricularly, both compounds produced behavioral deficits which were greater in naive than in trained animals. In vitro, acetylseco HC-3 inhibited ChAc activity with an I50 of 1 x 10-5 with Ch 10-2 and acetyl CoA 6.4 x 10-4 , while HC-3 had no inhibitory effects. Using rat brain homogenate as the enzyme source and commercial acetyl CoA for kinetic studies, acetylseco HC-3 was shown to be a mixed inhibitor of acetyl CoA and a competitive inhibitor of Ch.The in vivo actions of acetylseco HC-3 are consistent with those of a ChAc inhibitor. However, it is necessary to rule out the possibility that the drug may also compete with Ch for its transport across biological membranes like its deacetylated derivative HC-3.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33873/1/0000134.pd