First Report of Bacterial Leaf Spot of Swiss Chard Caused by Pseudomonas syringae pv. aptata in California.

From 1999 through 2003, a previously unreported disease was found on commercial Swiss chard (Beta vulgaris subsp. cicla) in the Salinas Valley, (Monterey County) California. Each year the disease occurred sporadically throughout the long growing season from April through September. Initial symptoms were water-soaked leaf spots that measured 2 to 3 mm in diameter. As disease developed, spots became circular to ellipsoid, 3 to 8 mm in diameter, and tan with distinct brown-to-black borders. Spots were visible from the adaxial and abaxial sides. Cream-colored bacterial colonies were consistently isolated from spots. Strains were fluorescent on King's medium B, levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction on tobacco (Nicotiana tabacum cv. Turk). The isolates, therefore, belong in LOPAT group 1 (1). Fatty acid methyl esters (FAME) analysis (MIS-TSBA version 4.10, MIDI Inc., Newark, DE) gave variable results that included Pseudomonas syringae, P. cichorii, and P. viridiflava with similarity indices ranging from 0.91 to 0.95. BOX-polymerase chain reaction (PCR) analysis gave identical banding patterns for the chard isolates and for known P. syringae pv. aptata strains, including the pathotype strain CFBP1617 (2). The bacteria were identified as P. syringae. Pathogenicity of 11 strains was tested by growing inoculum in nutrient broth shake cultures for 48 h, diluting to 10 × 6 CFU/ml, and spraying onto 5-week-old plants of Swiss chard cvs. Red, White, Silverado, and CXS2547. Untreated control plants were sprayed with sterile nutrient broth. After 7 to 10 days in a greenhouse (24 to 26°C), leaf spots similar to those observed in the field developed on all inoculated plants. Strains were reisolated from the spots and identified as P. syringae. Control plants remained symptomless. To investigate the host range of this pathogen, the same procedures were used to inoculate three strains onto other Chenopodiaceae plants: five cultivars of sugar beet (B. vulgaris), and one cultivar each of spinach (Spinacia oleracea) and Swiss chard. In addition, five chard strains and strain CFBP1617 were inoculated onto two cultivars of sunflower (Helianthus annuus), and one cultivar each of cantaloupe (Cucumis melo), sugar beet, spinach, and Swiss chard. All Swiss chard, cantaloupe, sunflower, and sugar beet plants developed leaf spots after 7 days. The pathogen was reisolated from spots and confirmed to be the same bacterium using BOX-PCR analysis. Spinach and untreated controls failed to show symptoms. All inoculation experiments were done at least twice and the results were the same. The phenotypic data, fatty acid and genetic analyses, and pathogenicity tests indicated that these strains are P. syringae pv. aptata. To our knowledge this is the first report of bacterial leaf spot of commercially grown Swiss chard in California caused by P. syringae pv. aptata. The disease was particularly damaging when it developed in Swiss chard fields planted for "baby leaf" fresh market products. Such crops are placed on 2-m wide beds, planted with high seed densities, and are sprinkler irrigated. This disease has been reported from Asia, Australia, Europe, and other U.S. states. References: (1) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966. (2) J. L. W. Rademaker et al. Mol. Microbiol. Ecol. Man. 3.4.3:1-27, 1998.

Studies on avian erythrocyte metabolism. XVII. Kinetics and transport properties of myo-inositol in chicken reticulocytes.

The uptake of myo-inositol was determined in a reticulocyte-enriched fraction prepared from chicken blood and compared with uptake in mature erythrocytes. While reticulocytes accumulated inositol at levels more than threefold that of the plasma concentration, erythrocyte levels were only slightly higher than that of the plasma concentration. The rate of uptake in reticulocytes was approximately 66 mumol/ml rbc/h compared to 5 mumol/ml rbc/h in mature erythrocytes when measured at an inositol medium concentration of 250 microM. The kinetic analysis of inositol influx by reticulocytes reveals a two component system: saturable and nonsaturable. The saturable component, which has a Km for inositol of approximately 222 microM, is Na-dependent. This Na-dependent saturable component, which presumably reflects active transport of inositol, accounts for 30-35% of the transport process. The saturable component is completely inhibited by amiloride but to a lesser extent by ouabain and bumetanide. Moreover, in the course of reticulocyte maturation, the saturable component is lost concomitantly with the completion of the synthesis of myo-inositol pentakisphosphate and the drastic decrease in the membrane permeability to inositol. In addition, phloretin and cytochalasin B, which bind to hexose carriers and inhibit hexose sugar transport, also inhibited inositol transport. The uptake of inositol was not affected by excesses of 3-O-methylglucose (100 mM) or by physiological concentrations of D-glucose. Thus, the transport mechanism of myo-inositol appears distinct from that of D-glucose.

Studies on avian erythrocyte metabolism. XVI. Accumulation of 2,3-bisphosphoglycerate with shifts in oxygen affinity of chicken erythrocytes.

The ability of the chicken erythrocyte to accumulate 2,3-bisphosphoglycerate (2,3-P2-glycerate) and its effect upon the oxygen affinity (P50) of the cell suspensions have been determined. Erythrocytes from chick embryos, which contain 4-6 mM 2,3-P2-glycerate, and from chickens at various ages, which contain 3-4 mM inositol pentakisphosphate but no 2,3-P2-glycerate, were incubated with inosine, pyruvate, and inorganic phosphate. Red blood cells from 20-day chick embryos incubated in Krebs-Ringer, pH 7.45, containing 20 mM inosine and 20 mM pyruvate had an increase in 2,3-P2-glycerate from 4.3 to 11.9 mM after 4 h. Importantly, as 2,3-P2-glycerate concentration increased there was a corresponding increase in P50 of the cell suspension. Further, erythrocytes from 9- and 11-week, and 7-, 14-, 24-, and 28-month-old chickens when incubated similarly with inosine and pyruvate accumulated 2,3-P2-glycerate with corresponding increases in P50 of the cell suspensions. The ability of the red cell to accumulate this compound under the incubation conditions used apparently decreases with age of the bird (e.g., 11.9 mM in the 20-day embryo to 1.1 mM in the 28-month-old chicken after 4 h incubation). Despite the presence of significant amounts of inositol-P5, the accumulation of 2,3-P2-glycerate markedly decreases oxygen affinity of the cell suspensions. The delta P50/mumol increase in 2,3-P2-glycerate in the red cells of the 20-day chick embryo after 4 h incubation is 1.5 Torr; conversely, the delta P50/mumol decrease in 2,3-P2-glycerate in the red cells of the 17-day embryo after 6 h incubation in the presence of sodium bisulfite is 2.8 Torr. The demonstrated ability of the chicken erythrocyte to accumulate 2,3-P2-glycerate in response to certain substrates suggests that regulation of concentration of this compound could contribute significantly to regulation of blood oxygen affinity in birds.

Studies on avian erythrocyte metabolism. XII. The synthesis and degradation of inositol pentakis (dihydrogen phosphate).

The pathway(s) of synthesis and degradation of inositol 1, 3, 4, 5, 6 pentakis (dihydrogen phosphate) (inositol-P5), found predominantly in the avian erythrocyte, are unknown. Myo-inositol (inositol), D-glucose, inosine, and phosphate have been studied as potential precursors of inositol-P5 synthesis in chicken erythrocytes. Whole blood from chickens at several ages has been incubated for prolonged periods and the concentration of inositol-P5 measured to determine the ability of the avian erythrocyte to catabolize inositol-P5. Incubation of erythrocyte suspensions from 5-day chicks with [U-14 C]myo-inositol (inositol) for 17 hr lead to the appearance of 19.8% of the radioactivity in the aqueous acid-soluble extract of the erythrocytes (RBC). Fractionation of this extract on an anion exchange column yielded five major radioactive peaks, three of which represent 1) free myo-inositol, accounting for 63.5% of the radioactivity; 2) myo-inositol monokis (dihydrogen phosphate) (inositol-P), representing 1.6% of the radioactivity; and 3) inositol 1, 3, 4, 5, 6 pentakis (dihydrogen phosphate) (inositol-P5), representing 27.0% of the label in the erythrocyte. Sodium fluoride did not inhibit the incorporation of [U-14 C]myo-inositol into inositol-P5. Similar incubations with D-[U-14 C]-glucose and [U-14 C]-inosine yielded no incorporation of radioactivity into inositol-P5. These data are consistent with the interpretation that inositol is the major precursor for synthesis of inositol-P5 in chick red cells. Incubation of whole blood from 1-, 5-, and 42-day chicks and mature birds at 40 C for as long as 72 hr resulted in increases in RBC inorganic phosphate (Pi) thought due primarily to depletion of adenosine triphosphate (ATP). Inositol-P5 content of RBC of 5- and 42-day birds decreased 28 and 20%, respectively, after 72 hr, but no change was noted in inositol-P5 levels of RBC from mature birds. The red cells of the mature bird appear to be unable to catabolize inositol-P5 at significant rates. The apparent inability of the chicken erythrocyte to alter readily its concentration of inositol-P5 suggests that the hemoglobin oxygen delivery system of birds may be less adaptable to changing oxygen requirements by regulating the concentration of hemoglobin modulator than is that of the mammals.

A reexamination of the potential comedogenicity of sulfur.

The present study was designed to reexamine the question of the potential comedogenicity of topical sulfur. Studies were done by two different investigators in two separate institutions with groups of 12 and 40 subjects, respectively. Biopsy specimens were obtained from the occluded test sites before and after a six-week period of treatment. Each subject received a patch test of 5% sulfur in either an octoxynol 9 (Triton X-100) or a carbomer 934P (Carbopol 934P) vehicle and one of two controls consisting of the Triton X-100 vehicle or a dry patch test. We conclude that no trend or correlation was noted between the presence or absence of sulfur in the formulation and the appearance of comedones. The Triton X-100 vehicle itself appeared to be comedogenic under the experimental conditions.

Studies on avian erythrocyte metabolism. VII. Effect of inositol pentaphosphate and other organic phosphates on oxygen affinity of the embryonic and adult-type hemoglobins of the turkey embryo.

The effects of 2, 3-diphosphoglyceric acid (2, 3-DPG), adenosine triphosphate (ATP), inositol tetraphosphate (ITP), inositol pentaphosphate (IPP), and inositol hexaphosphate (IHP) on oxygen affinity of whole stripped hemoglobin (WSH), hemoglobin H (Hb-H; hatching hemoglobin), hemoglobin A (Hb-A), and hemoglobin D (Hb-D) isolated from erythrocytes (RBC) of the 25-day turkey embryo have been studied. The order of the decrease in oxygen affinity induced by these organic phosphates, at molar ratios of phosphate compound to hemoglobin (tetramer) between 2 and 4, is 2, 3-DPG less than ATP less than ITP less than IPP less than IHP. 2, 3-DPG shows a slightly greater effect on reducing oxygen affinity of Hb-H than on either adult-type hemoglobin. The effect of IPP upon lowering the oxygen affinity of either WSH, Hb-H, Hb-A, or Hb-D is approximately 20 percent less than IHP. The effects of the various organic phosphates upon the Hill constant, n, of these purified hemoglobins is variable but appears to reach a maximum when the molar ratio of organic phosphate to hemoglobin (tetramer) is 2 or greater. None of the physiologically occurring organic phosphates has a significant preferential interaction with any specific hemoglobin. These experiments strengthen and support our earlier conclusion, that the changes in whole blood oxygen affinity which occur during avian development result from the changes in composition of the intraerythrocytic organic phosphates.

Studies on avian erythrocyte metabolism. 5. Relationship between the major phosphorylated metabolic intermediates and while blood oxygen affinity in embryols and poults of the domestic turkey (Meleagris gallopavo).

The changes in organic phosphates of turkey erythrocytes (RBC) have been determined in relation to the changes in oxygen affinity of whole blood during growth of the embryo and poult. On a molar basis, 2,3 diphosphoglyceric acid (2,3-DPG) is the predominant organic phosphate of erythrocytes from turkey embryos during the last week of incubation. However, on the basis of relative % phosphate, 2,3-DPG is the major organic phosphate of the erythrocytes from turkey embryos on day 23 and 25 of incubation only. With the exception of day 23 and 25 incubation, adenosine triphosphate (ATP) represents the major organic phosphate of the erythrocytes of the turkey embryo and poult during the last week of embryonic development and through the first 29 days after hatching. The whole blood P50 during the last week of incubation and the first 8 days after hatching correlates best with the amount of ATP in the erythrocytes. The effects of inositol pentaphosphate on P50 of the whole blood is much more gradual and appears to become of major influence after 2-3 weeks post-hatching.