Genetic markers in inbred clones of cultivated diploid potatoes

Summary Selfing 24-chromosome hybrids derived by crossing groups Phureja and Stenotomum with the group Tuberosum haploid US-W 4 has produced progenies segregating for many traits. Monogenic segregation ratios of previously described marker genes were confirmed and the inheritance of two new trats was determined. The previously reported linkage between factors for tuber shape and tuber pigmentation was confirmed. The genotypes for several marker genes have been established on the basis of progeny tests for 31 self-compatible diploid clones. These cultivated diploid stocks with known genotypes for marker genes have great potential value for future genetic investigations in potatoes.

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Zusammenfassung Der Mangel an geeigneten, gut definierten Markierungsgenen hat genetische Untersuchungen an Kartoffeln gehemmt. Eine Fülle potentiell m?glicher genetischer Variation ist in den selbstunvertr?glichen kultivierten diploiden Formen vonSolanum tuberosum L., Gruppe Phureja und Gruppe Stenotomum, vorhanden. Diese Variation kann in den selbst-vertr?glichen, 24-chromosomigen Hybriden, die aus der Kreuzung dieser kultivierten Diploiden mit der Gruppe Tuberosum haploid US-W 4 stammen, ausgenützt werden. Nachkommenschaften geselbsteter 24-chromosomiger Hybrid-Klone wurden auf Aufspaltung der früher beschriebenen MarkierungsgeneP, R, Ac, B, I undF und potentiell wertvoller, neuer Markierungsgene untersucht. Die Bonitierung wurde sowohl visuell als auch durch Dünnschicht-Chromatographie der Blüten- und Knollenschalenpigmente vorgenommen. Es wurde ein neues Merkmal gefunden, das die Verteilung von Pigmenten auf der Fruchtknotenwand kontrolliert. Diese Eigenschaft scheint monogenetisch dominant vererbt zu werden, und es wurde ihr das Gen-SymbolOw gegeben. Im Pflanzenmaterial, das für diese Arbeit verwendet wurde, warOw mitI in der Kopplungsphase verbunden und mitF in der Repulsionsphase (Tabellen 1 und 2). Ein die Knollenform kontrollierendes Hauptgen scheint ebenfalls mit dieser Gruppe verbunden zu sein (Tabelle 3). Ein chemogenetischer Markierer wurde in Chromatogrammen entdeckt. Unter ultraviolettem Licht erscheint er als ein gl?nzendes, fluoreszierendes, blaues Band, im Aussehen sehr ?hnlich der Chlorogens?ure, aber mit einem niedrigeren Rf-Wert bei gleichem Laufmittel. Dieses Band scheint durch ein einzelnes dominantes Gen vererbt zu sein (Tabelle 4). Auf Grund der aus der visuellen Beurteilung und der Laboruntersuchung der Nachkommenschaften erhaltenen Information wurden die Genotypen von 31 selbstvertr?glichen Klonen für einige einfach vererbte Merkmale bestimmt. Zum Beispiel konnte nach der Analyse der durch Selbstung des Klons US-W 8775-34 erhaltenen Nachkommenschaft der Genotyppp. RR. FF. ii. owow. Acac bestimmt werden. Klone, wie dieser, mit bekannten Genotypen für einzelne Markierungsgene haben grossen potentiellen Wert für zukünftige genetische Untersuchungen an Kartoffeln.

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Résumé La rareté de marqueurs génétiques appropriés, bien définis, a handicapé les études génétiques chez la pomme de terre. Il existe une abondante variation génétique, potentiellement utilisable dans les diplo?des cultivés auto-incompatibles,Solanum tuberosum L. groupe Phureja et groupe Stenotomum. Cette variation peut être exploitée dans les hybrides auto-compatibles à 24 chromosomes dérivés de croisements de ces diplo?des cultivés avec le haplo?de US-W4 du groupe Tuberosum. On a retenu les descendances issues de l'autofécondation de clones hybrides à 24 chromosomes pour la ségrégation de gènes marqueurs précédemment décrits,P, R, Ac, B, I etF et de nouveaux gènes potentiellement utilisables. Le classement a été fait à la fois d'après examen visuel et d'après l'analyse chromatographique en couche mince de pigments de fleur et de la peau du tubercule. On a découvert un caractère nouveau qui règle l'apparition des pigments sur la paroi ovarienne. Ce caractère para?t être hérité comme un simple gène dominant, et on lui a attribué le symboleOw. Dans le matériel ‘plante’ utilisé dans la présente étudeOw est lié àI dans la phase d'accouplement et avecF dans la phase de séparation (Tableaux 1 et 2). Un gène majeur qui règle la forme du tubercule para?t également associé avec de groupe de liaison (linkage) (Tableau 3). On détecte un marqueur chimiogénétique dans les chromatogrammes. Sous lumière ultraviolette, il appara?t comme une bande d'un bleu brillant fluorescent très sensible en apparence à l'acide chlorogénique, mais avec une valeur inférieure Rf dans le même solvant de développement. L'hérédité de cette bande est semblable à celle d'un simple gène dominant (tableau 4). On a déterminé les génotypes de 31 clones auto-compatibles pour plusieurs caractères à hérédité simple, en se basant sur le comptage visuel et l'examen au laboratoire des descandances. Par exemple, d'après l'analyse de la descendance d'autofécondation du clone US-W 8775-43, on peut attribuer à celui-ci le génotypepp. RR. FF. ii. owow. Acac. Des clones tels que celui-ci, de génotypes connus pour plusieurs gènes marqueurs, possèdent une grande valeur potentielle pour les futures études génétiques chez la pomme de terre.

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Cooperative investigations of the Plant Science Research Division, Agricultural Research Service, U.S. Department of Agriculture, and the Wisconsin Agricultural Experiment Station.     

Allelopathy in the rhizosphere and amended soil of Chenopodium murale L.

Soil infested with Chenopodium murale and amended with it were investigated to verify their allelopathic effects on seedling emergence and some growth and physiological parameters of five test species, Trifolium alexandrinum, Triticum aestivum, Melilotus indicus, lycopersicum esculentum and Cucumus sativus. The two types of soil exhibited phytotoxic effects on the seedling emergence of the test species. Growth and physiological parameters were significantly inhibited when the soil was amended with a high concentration of C. murale tissues. Soil amended with shoot tissue had more inhibitory effects than soil amended with root tissue, at the same concentration. M. indicus was more inhibited than the other species in relation to leaf area, dry matter, pigment, carbohydrates and protein contents.     

Pharmacokinetics of ceftiofur crystalline free acid after single subcutaneous administration in lactating and nonlactating domestic goats (Capra aegagrus hircus)

Doré, E., Angelos, J. A., Rowe, J. D., Carlson, J. L., Wetzlich, S. E., Kieu, H. T., Tell, L. A. Pharmacokinetics of ceftiofur crystalline free acid after single subcutaneous administration in lactating and nonlactating domestic goats (Capra aegagrus hircus). J. vet. Pharmacol. Therap. 34 , 25–30. Six nonlactating and six lactating adult female goats received a single subcutaneous injection of ceftiofur crystalline free acid (CCFA) at a dosage of 6.6 mg/kg. Blood samples were collected from the jugular vein before and at multiple time points after CCFA administration. Milk samples were collected twice daily. Concentrations of ceftiofur and desfuroylceftiofur‐related metabolites were measured using high‐performance liquid chromatography. Data were analyzed using compartmental and noncompartmental approaches. The pharmacokinetics of CCFA in the domestic goat was best described by a one compartment model. Mean (±SD) pharmacokinetic parameters were as follows for the nonlactating goats: area under the concentration time curve_0–∞ (159 h·μg/mL ± 19), maximum observed serum concentration (2.3 μg/mL ± 1.1), time of maximal observed serum concentration (26.7 h ± 16.5) and terminal elimination half life (36.9 h; harmonic). For the lactating goats, the pharmacokinetic parameters were as follows: area under the concentration time curve_0–∞ (156 h·μg/mL ± 14), maximum observed serum concentration (1.5 μg/mL ± 0.4), time of maximal observed serum concentration (46 h ± 15.9) and terminal elimination half life (37.3 h; harmonic). Ceftiofur and desfuroylceftiofur‐related metabolites were only detectable in one milk sample at 36 h following treatment. There were no significant differences in the pharmacokinetic parameter between the nonlactating and lactating goats.     

Influence of early postmortem protein oxidation on beef quality

The objective of this study was to examine the effect of early postmortem protein oxidation on the color and tenderness of beef steaks. To obtain a range of oxidation levels, the longissimus lumborum muscles (LM) from both strip loins of 20 steers fed either a finishing diet with vitamin E (1,000 IU per steer daily, minimum of 126 d [VITE]; n = 10 steers) or fed the same finishing diet without vitamin E (CON; n = 10 steers) were used. Within 24 h after slaughter, the LM muscle from each carcass was cut into 2.54-cm-thick steaks and individually vacuum packaged. Steaks from each steer were assigned to a nonirradiated group or an irradiated group. Steaks were irradiated within 26 h postmortem, and were aged at 4 degrees C for 0, 1, 3, 7, and 14 d after irradiation. Steaks from each diet/irradiation/aging time treatment were used to determine color, shear force, and degree of protein oxidation (carbonyl content). Steaks from steers fed the VITE diet had higher (P < 0.01) alpha-tocopherol contents than steaks from steers fed the CON diet. Immediately following irradiation, steaks that had been irradiated had lower (P < 0.05) L* values regardless of diet. Irradiated steaks, regardless of diet, had lower a* (P < 0.05) and b* (P < 0.01) values than nonirradiated steaks at all aging times. Carbonyl concentration was higher (P < 0.05) in proteins from irradiated steaks compared to nonirradiated steaks at 0, 1, 3, and 7 d postirradiation. Immunoblot analysis showed that vitamin E supplementation decreased the number and extent of oxidized sarcoplasmic proteins. Protein carbonyl content was positively correlated with Warner-Bratzler shear force values. These results indicate that increased oxidation of muscle proteins early postmortem could have negative effects on fresh meat color and tenderness.     

Effect of pH and ionic strength on mu- and m-calpain inhibition by calpastatin

The objectives of this study were to determine the extent to which pH and ionic strength influence mu- and m-calpain activity and the inhibition of calpains by calpastatin. Calpastatin, mu-calpain, and m-calpain were purified from at-death porcine semimembranosus. Mu-calpain or m-calpain (0.45 U) were incubated with the calpain substrate Suc-Leu-Leu-Val-Tyr-7-amino-4-methyl coumarin in the presence of calpastatin (0, 0.15, or 0.30 U of calpain inhibitory activity) under the following pH and ionic strength conditions: pH 7.5 and 165 mM NaCl or 295 mM NaCl; pH 6.5 and 165 mM NaCl or 295 mM NaCl; and pH 6.0 and 165 mM NaCl or 295 mM NaCl. The reactions were initiated with addition of 100 microM (mu-calpain) or 1 mM CaCl2 (m-calpain), and calpain activity was recorded at 30 and 60 min. Mu-calpain had the greatest (P < 0.01) activity at pH 6.5 at each ionic strength. Higher ionic strength decreased mu-calpain activity (P < 0.01) at all pH conditions. Inhibition percent of mu-calpain by calpastatin was not affected by pH; however, it was influenced by ionic strength. Inhibition of mu-calpain by calpastatin was higher (P < 0.01) at 295 mM NaCl than at 165 mM NaCl when 0.3 units of calpastatin were included in the assay. Activity of m-calpain was greater (P < 0.01) at pH 7.5 than at pH 6.5. m-Calpain activity was not detected at pH 6.0. Inhibition of m-calpain was greater (P < 0.01) when 0.15 and 0.3 U calpastatin were added at pH 6.5 than 7.5 at 165 mM NaCl, whereas percentage inhibition of m-calpain was greater (P < 0.01) at 295 mM than 165 mM NaCl at pH 7.5 and 6.5. These observations provide new evidence that defines further the influence of pH decline and increased ionic strength on mu-calpain, m-calpain, and calpastatin activity, thereby helping to more accurately define a role for these enzymes in the process of postmortem tenderization.     

Assessing Degree of Cook During Corn Nixtamalization: Impact of Processing Variables

Nixtamalization involves cooking and steeping corn in a lime solution, washing the corn (nixtamal), and stone grinding nixtamal to form a corn dough or masa. Masa is used to produce nixtamalized products (corn tortillas, tortilla chips, corn chips, taco shells, etc.) by forming and baking or deepfat frying. The degree of corn kernel cook determines the quality and texture of masa. Response surface methodology (RSM) was used as an experimental design to study the impact of process variables (cook temperature, cook time, initial steep temperature, and steep time) on the degree of cook measured using a Rapid Visco Analyser (RVA) and differential scanning calorimetry (DSC). RSM data exhibited significant (P < 0.005), although not predictive, linear models for RVA peak viscosity (r² = 0.63), setback (r² = 0.61), final viscosity (r² = 0.61), and peak time (r² = 0.57), indicating a dependence of these parameters on nixtamalization conditions. Peak viscosity, setback, and final viscosity increased linearly with steep time. DSC enthalpy (r² = 0.83) and peak temperature (r² = 0.89) of freezedried masa also exhibited significant (P < 0.0001) linear regression models with processing variables. DSC enthalpy increased with an increase in steep time, suggesting that starch is annealed during steeping. This study demonstrated that fundamental starch properties were altered on extended steeping during nixtamalization.