Fall applications of MCPA to improve tiller synchrony and reduce lodging in winter wheat

Poor developmental spike synchrony in wheat (Triticum aestivum L.) can reduce the effectiveness of chemical treatments keyed on reproductive events. The broadleaf herbicide (2-methyl-4-chlorophenoxy) acetic acid (MCPA) can be used to retard the development of wheat tillers if applied to winter wheat in the fall prior to the initiation of tiller primordia. Fall applications of 0.5 kg ha^–1 MCPA were sufficient to reduce the tillering rate by 20–30% while providing a slight, but statistically non-significant, increase in yield. Significant increases in kernels spike^–1 were observed in the MCPA treatments. The effect of MCPA on kernels spike ^–1 could be modulated by nitrogen fertility and planting density. A linear relationship between spike number m^–2 and planting density could be observed with MCPA treatments. Reductions in total number of spikes m^–2, but an increase in kernels spike^–1, resulted in significant improvements in tiller synchrony. Improved tiller synchrony is important in optimizing chemical treatments where applications are based on the developmental stages of the spike. Significant reductions in plant height and subsequent reductions in lodging under high nitrogen fertility and high plant populations were observed with MCPA treatments.     

Glucose-Modified Low Density Lipoprotein Enhances Human Monocyte Chemotaxis

In diabetes mellitus the progression of atherosclerosis is accelerated. The interaction of glucose with athero-genic lipoproteins may be relevant to the mechanisms responsible for this vascular damage. The aim of this study was to examine the effect of glucose-modified low density lipoprotein (LDL) on human monocyte chemotaxis and to investigate the roles of oxidation and glycation in the generation of chemotactic LDL. Cu(II)-mediated LDL oxidation was potentiated by glucose in a dose-dependent manner and increased its chemotactic activity. Incubation with glucose alone, under conditions where very little oxidation was observed, also increased the chemotactic property of LDL. Neither diethylenetriamine pentaacetic acid (DETAPAC) nor aminoguanidine, which both inhibited LDL oxidation, completely inhibited the chemotactic activity of glycated oxidised LDL. The results suggest that both oxidation and glycation contribute to increased chemotactic activity.     

Plasma variations of pituitary hormones during extracorporeal circulation

In this research we have determined the behaviour of hypophisary hormones determined by radioimmunoassay. We have noted a constant increase of GH and HPrL. In one case we have seen also the decrease of LH and FSH. This changes are determined by the large dose of heparin necessary during C.E.C.     

Effect of membrane voltage on the plasma membrane H(+)-ATPase of Saccharomyces cerevisiae

A novel system for generating large interior positive membrane potentials in proteoliposomes was used to examine the effects of membrane voltage on reconstituted plasma membrane H(+)-ATPase from Saccharomyces cerevisiae. The membrane potential-generating system was dependent upon the lipophilic electron carrier tetracyanoquinodimethane, located within the bilayer, to mediate electron flow from vesicle entrapped ascorbate to external K3Fe(CN)6. Membrane potential formation was followed by the potential-dependent probe oxonol V and was found to rapidly reach a steady-state which lasted at least 90 s. A membrane potential of approximately 254 mV was determined under optimal conditions and ATP hydrolysis by wild-type H(+)-ATPase was inhibited from 34 to 46% under these conditions. In contrast, membrane potential had little effect on pma1-105 mutant enzyme suggesting that it is defective in electrogenic proton translocation. Applied membrane voltage was also found to alter the sensitivity of wild-type enzyme to vanadate at concentrations less than 50 microM. These data suggest a coupling between the charge-transfer and ATP hydrolysis domains and establish a solid basis for future probing of the electrogenic properties of the yeast H(+)-ATPase.     

Continuous multiplication of rabbit tracheal epithelial cells in a defined,hormone-supplemented medium

Summary An improved Ham’s F12 nutrient medium supplemented with epidermal growth factor (EGF), insulin (INS), and transferrin (TF) was developed for continuous proliferation and clonal growth of primary rabbit tracheal epithelial (TE) cells in culture. The addition of small quantities of fetal bovine serum (FBS) (0.01 to 0.1%) to cultures had little measurable stimulation on TE cell growth and plating efficiency. However, serum levels higher than 0.1% inhibited cell growth and also masked the growth stimulating activities of EGF and INS despite an increase in cell attachment. Under this defined, hormone-supplemented medium, and in the presence of a trace amount of serum (0.01%), 10 to 20% of the protease-dissociated TE cells attached to the culture dish followed by at least four population doublings during 7 to 10 d of culture. Clonal growth occurred at a seeding density of 17 cells/cm² with a plating efficiency of 6 to 8%. Confluent primary cultures could be passaged two to four times by treatment with a 0.1% trypsin-1 mM EDTA solution and a total of 10 to 30 population doublings of in vitro life span were obtained. The epithelial nature of cultured cells was confirmed by indirect immunofluorescent staining with antikeratin antibody as well as by transmission electron microscopy. This study shows that using this improved hormone-supplemented medium, rabbit TE cells can be maintained in culture for extended periods of time without the aid of a fibroblast feeder layer or explant tissue. This system could be useful for the study of cell differentiation of tracheal epithelium.     

Agarose-acrylamide gradient gel electrophoresis of proteins

A new agarose-acrylamide gradient slab gel electrophoresis system is described. The preparation of this new gel has been facilitated by the use of agarose with a relatively low gelation temperature. Fractionation of marker proteins and crosslinked proteins from a subcellular cytoskeletal preparation on agarose-acrylamide gradient gels is compared to that found using other acrylamide gel electrophoresis systems.     

Actions of a nicotinic agonist,DMPP, on intestinal ion transport invitro

High-dose carbachol (10^?3 M) has previously been shown to cause NaCl absorption in short-circuited rabbit ileum. The mechanism of this effect may be norepinephrine release induced by carbachol activation of presynaptic nicotinic receptors on adrenergic neurons. Norepinephrine then interacts with postsynaptic α-adrenergic receptors on intestinal mucosal cells to stimulate neutral NaCl absorption and inhibit electrogenic bicarbonate secretion. The present paper examines the $\text{in vitro}$ intestinal ion transport effects of DMPP an agent which is more specific than carbachol on nicotinic cholinergic receptors. DMPP (10^?5 M) caused a transient increase followed by prolonged depression of the short-circuit current, increased NaCl absorption and increased tissue conductance. This effect was antagonized by hexamethonium and phentolamine. It is concluded that nicotinic cholinergic agents stimulate norepinephrine release from adrenergic nerves and effect intestinal ion transport just as norepinephrine does.     

Plasmodium berghei: Glycolytic enzymes of the infected mouse erythrocyte

This paper documents the maximal activities of the glycolytic enzymes in the red blood cells of normal mice and mice infected with Plasmodium berghei. There appears to be sufficient parasite-related activity of each glycolytic enzyme to support the increased glycolytic rate, i.e., increased glucose consumption, of the parasite-infected red blood cell. The relative proportions of glycolytic enzyme activities in parasite-infected red cells are different from the proportions in either normal or reticulocyte-rich blood, indicating that the increased enzyme activities associated with infected cells are not due to contaminating host red cells or reticulocytes. A comparison of maximal enzyme activities to the rate of whole cell glucose consumption indicates that different glycolytic control mechanisms are operating in the infected RBC from those in the uninfected cells.     

Cerebrospinal fluid and serum oligoclonal IgG bands in rabbits with experimental allergic encephalomyelitis

Rabbits sensitized with whole nervous tissue or myelin basic protein (MBP) plus adjuvant and developing experimental allergic encephalomyelitis (EAE) were studied for the presence of oligoclonal immunoglobulin (Ig) bands in spinal fluid and serum. Samples obtained prior to sensitization and at the time of sacrifice were concentrated and subjected to agar gel electrophoresis. Of 11 rabbits receiving whole nervous tissue and developing severe clinical signs of EAE, 7 showed new oligoclonal Ig bands in spinal fluid and in serum obtained 19 days or more after sensitization. With MBP sensitization, 2 of 6 rabbits exhibited new spinal fluid bands, while all 6 rabbits studied demonstrated serum banding. The bands were identified as IgG by immunochemical studies using peroxidase-labeled antisera and byStaph. protein A absorption. The majority of animals showed no banding in presensitization samples. The finding of oligoclonal IgG in EAE reveals yet another immunologic correlation between EAE and the human demyelinating disease, multiple sclerosis.