The effect of moisture potential on growth and survival of root nodule bacteria in peat culture and on seed

Peat from three sources was dried, milled and packed separately in polyethylene bags and sterilized by irradiation. The carrier was impregnated with broth cultures of either Rhizobium leguminosarum bv. trifolii strain WU95, Bradyrhizobium japonicum strain CB1809 or B. lupini strain WU425 and sterile water to provide five moisture potentials in the range > - 1 × 10⁴ - 1 × 10⁶ Pa. The packets were stored at 26°C under conditions which restricted moisture loss. Numbers of root nodule bacteria were counted at intervals up to 12 weeks. No single moisture potential was optimum for all strains in all carriers because of a significant ( P < 0.05) interaction between moisture potential × strain × carrier × time. Where direct comparisons could be made, all strains survived best at - 1 × 10⁴ and/or −3.2 × 10⁴ Pa. Seeds of Trifolium subterraneum and polypropylene beads (used to avoid seed coat toxicity), were inoculated with WU95 prepared in two sources of peat and at each of the above moisture potentials and stored at 15°C. Seed coat toxicity significantly effected the log death rate ( k ) of WU95 on subterraneum clover seed for the period 0–0.25 d ( k 1.796) compared with k - 0.399 for polypropylene beads. In the first 24 h moisture did not affect survival but by 28 d rhizobia grown in Badenoch peat survived best at −3.2 × 10⁴ Pa. In Millicent peat, survival was equally as good at −3.2 × 10⁴ and −1 × 10⁴ Pa.     

Effects of boundary layer conductance on substomatal pressures of carbon dioxide

Abstract. Gas exchange measurements were made on single leaves of three C₃ and one C₄ species at air speeds of 0.4 and 4.0 m s⁻¹ to determine if boundary layer conductance substantially affected the substomatal pressure of carbon dioxide. Boundary layer conductances to water vapour were 0.4 to 0.5 mol m⁻² s⁻¹ at the lower air speed, and 1.2 to 1.5 mol m⁻² s⁻¹ at the higher air speed. Substomatal carbon dioxide pressures were about 5 Pa lower at low boundary layer conductance in the C₃ species, and about 3 Pa lower in the C₄ species when measurements were made at high and moderate photosynthetic photon flux densities. No evidence of stomatal adjustment to altered boundary layer conductance was found. Photosynthetic rates at high photon flux densities were reduced by about 20% at the low air speed in the C₃ species. The commonly reported values of substomatal carbon dioxide pressure for C₃ and C₄ species were found to occur only when measurements were made at the higher air speed.     

Electrophoretic types of leucine aminopeptidase in sheep serum

Leucine aminopeptidase in sheep serum was studied by starch gel electrophoresis. Two phenotypes, A and B, were observed, of which the former was present in 70–90 % of all the sheep examined. These two phenotypes have been shown to be controlled by a single autosomal locus, with two alleles Lay^A and Lap^B . The Lap^A allele is dominant. The frequencies of Lap phenotypes and alleles were determined in eleven Spanish and two foreign breeds. Serum alkaline phospatase and serum leucine aminopeptidase are electrophoretically distinct.     

Oxygen-dependent stomatal opening in Zea mays leaves. Effect of Light and carbon dioxide

The oxygen requirement for stomatal opening in maize plants ( Zea mays L. hybrid INRA 508) was studied at different CO₂ concentrations and light intensities. In the absence of CO₂, stomatal opening always required O₂, but this requirement decreased with increasing light intensity. In darkness, the lowest O₂ partial pressure needed to obtain a weak stomatal movement was about 50 Pa. This value was lowered to ca 10 Pa in light (320 μmol m⁻² s⁻¹).
On the other hand. in the absence of O₂, CO₂enabled stomatal opening to occur in the light, presumably due to the evolved photosynthetic O₂. Thus, CO₂, which generally reduced stomatal aperture, could induce stomatal movement in anoxia and light. The effect of CO₂ on stomatal opening was closely dependent on O₂ concentration and light intensity. Stomatal aperture appeared CO₂-independent at an O₂ partial pressure which was dependent on light intensity and was about 25 Pa at 320 umol m⁻² s⁻¹.
The presence of a plasmalemma oxidase, in addition to mitochondrial oxidase, might explain the differences in the O² requirement at various light intensities. The possible involvement of such a system in relation to the effect of CO₂ is discussed.     

Studies on strong and weak killer phenotypes of wine yeasts: production, activity of toxin in must, and its effect in mixed culture fermentation

R.A. MUSMANNO, T. DI MAGGIO and G. CORATZA.1999.Two different killer phenotypes were detected among K⁺ (killer) yeasts isolated from spontaneous wine fermentations using a plate bioassay. The two phenotypes differed in their degree of killer activity, and were designated as SK⁺(strong killer) and WK⁺(weak killer). Strains showing either phenotype were assayed for expression of killer activity under different growth conditions. Growth in must negatively affected expression of the killer activity of both phenotypes. The supernatant fluids from must cultures showed a lower killing effect than those from yeast phosphate dextrose broth (YPDB) cultures. The ability of the two K⁺ phenotypes to prevail on K-sensitive yeasts was studied in mixed-culture fermentation experiments. Under these conditions, only strains showing SK⁺ phenotype were able to prevail on the K-sensitive yeasts. These results suggest that the K⁺ phenotype could play a relevant role in spontaneous fermentations provided that the strain exhibits an SK⁺ phenotype, and that the latter phenotype should be preferred when selected K + strains are to be used as fermentation starters.     

Bovine plasma alkaline phosphatase activity in relation to age, J substance and β-lactoglobulin phenotypes

In Jersey cattle the plasma alkaline phosphatase (AP) activity was found to be markedly age-dependent. Among animals grouped with regard to age a marked decrease in the average plasma AP activity was shown to take place until an age of 2¹/₂ to 3 years. For the J substance and β-lactoglobulin phenotypes a dependency of age was not observed in the material studied.
Excluding animals less than 3 years old and thus eliminating variation in AP activity due to age, a significant association (P<0.01) between AP activity and J phenotypes was observed among 91 animals. The J^cs phenotype was associated with low AP activity and the j^a phenotype with high AP activity. On the average the J substance phenotypes, J^cs, J^s and j^a, exhibit an increasing plasma AP activity of 3.6, 4.2 and 6.8 King Armstrong Units, respectively, and a corresponding decrease in J substance.
In a similar comparison of the β-lactoglobulin phenotypes and plasma AP activity involving 82 lactating cows, an excess of the β-lactoglobulin BB phenotypes with high AP activity just at P = 0.05 was observed.     

Effects of manganese toxicity on photosynthesis of white birch (Betula platyphylla var. japonica) seedlings

The effects of manganese (Mn) toxicity on photosynthesis in white birch ( Betula platyphylla var. japonica ) leaves were examined by the measurement of gas exchange and chlorophyll fluorescence in hydroponically cultured plants. The net photosynthetic rate at saturating light and ambient CO₂ (C_a) of 35 Pa decreased with increasing leaf Mn concentrations. The carboxylation efficiency, derived from the difference in CO₂ assimilation rate at intercellular CO₂ pressures attained at C_a of 13 Pa and O Pa, decreased with greater leaf Mn accumulation. Net photosynthetic rate at saturating light and saturating CO₂ (5%) also declined with leaf Mn accumulation while the maximum quantum yield of O₂ evolution at saturating CO₂ was not affected. The maximum efficiency of PSII photochemistry (F_v/F_m) was little affected by Mn accumulation in white birch leaves over a wide range of leaf Mn concentrations (2–17 mg g₋₁ dry weight). When measured in the steady state of photosynthesis under ambient air at 430 μmol quanta m₋₂ s₋₁, the levels of photochemical quenching (qP) and the excitation capture efficiency of open PSII (F'^v/F'^m) declined with Mn accumulation in leaves. The present results suggest that excess Mn in leaves affects the activities of the CO² reduction cycle rather than the potential efficiency of photochemistry, leading to increases in Q_A reduction state and thermal energy dissipation, and a decrease in quantum yield of PSII in the steady state.     

Studies on the transferrins of goats. 3. Evidence for a third transferrin allele

A new allele Tf ^c in serum transferrin of goats is postulated. It was considered that serum transferrins in goats classified into six phenotypes are genetically controlled by three codominant alleles, Tf ^A, Tf ^B and Tf ^c. Frequencies of Tf ^c were low in native goats in Korea, Philipines and Thailand, and this allele is yet to be observed in other breeds of goats.     

The evidence of erythrocyte acid phosphatase by starch gel electrophoresis in the pig

Up to now no polymorphism of acid phosphatase in pigs has been reported. According to the method of Radam & Strauch (1971) 3 phenotypes of acid phosphatase, A, AB and B, were identified in haemolysates from 284 German Landrace boars. The corresponding gene frequencies¹ were found: 0.74 for P ^A and 0.26 for P^B.     

Polymorphism of red cell acid phosphatase in dogs

In fresh red cell haemolysates from Labrador retriever dogs three acid phosphatase (Pac) phenotypes were found by starch gel electrophoresis. Family data were consistent with the theory that the Pac phenotypes are controlled by two codominant, autosomal alleles, designated Pac ^F and Pac ^S.     

Polymorphism of alkaline ribonuclease in the leucocytes of Black-and-White cattle

Studies were carried out on the polymorphism of alkaline ribonuclease in Black-and-White cattle in the north-eastern region of Poland. Leucocytes isolated from peripheral blood were used. Three phenotypes were defined, consisting of the combination of two alleles. The gene frequency was: q⁴= 0,7082, q^B= 0,2918. In calves the frequency of allele RNA-ase^B and number of RNA-ase^A/ RNA -ase^B heterozygotes were higher than in adult animals.     

Autoaggregation and adhesion ability in a Bifidobacterium suis strain

On the basis of autoaggregation ability, two different phenotypes (Agg⁺ and Agg⁻) were selected from a strain (BSu895) of Bifidobacterium suis . The relationship between autoaggregation and adhesion of bacteria to intestinal tissue was investigated by observing the adhesivity of the two phenotypic variants to ileum and colon tissue pieces collected from six new-born piglets. The results suggest that there is a good relationship between autoaggregation and adhesion as variant Agg⁺ (autoaggregating) has a stronger adhesion ability than Agg⁻ (non-autoaggregating).     

Polymorphism of phosphoglucomutase in a German breed cattle

Haemolysates from cattle belonging to the Hochfleckvieh breed (N = 42), were studied for electrophoretic variation of phosphoglucomutase. Three phenotypes were observed which could be explained on the basis of two alleles PGMi^A and PGMi^B. The PGM'^B frequency of 0.7325 is comparatively lower than in other breeds.     

Segregational and structural instability of recombinant plasmid carrying genes for naphthalene degrading pathway

The stability of recombinant plasmid carrying genes for naphthalene mineralization was determined. A strain of Pseudomonas putida capable of mineralizing naphthalene (Nap⁺) via salicylate (Sal⁺) was isolated, and all regulatory and structural genes for the whole pathway were found to be encoded on a 25 kb Eco RI fragment of an approximately 83 kb plasmid present in this strain. The 25 kb Eco RI fragment was cloned into a tetracycline-resistant (Tc^R) cloning vector pLAFR3 and the recombinant plasmid, pRKJ3 (Nap⁺, Sal⁺, Tc^R), thus obtained was transferred into the plasmid-free strain Pseudomonas putida KT2442 in order to test the stability of the plasmid. Plasmid pRKJ3 was found to be segregationally and/or structurally unstable, depending on the growth conditions. Two types of novel derivative strains having the phenotypes Nap⁻, Sal⁺, Tc^R and Nap⁻, Sal⁻, Tc^R with specific deletions of approximately 2 kb and 18 kb, respectively, were obtained.     

Genetic variants of phosvitin in egg yolk of the Japanese quail, Coturnix coturnix japonica

Summary. Phosvitin polymorphism in egg yolk of the Japanese quail was found by horizontal polyacrylamide gradient gel electrophoresis. Six phenotypes of yolk phosvitin designated A, B, C, AB, AC, and BC were observed in a population of 281 birds. Analysis of family data revealed that the phenotypic variation of quail yolk phosvitins was controlled by an autosomal Pv locus with three codominant alleles, Pv^a, Pv^b and Pv^c. The gene frequencies of Pv^a, Pv^b and Pv^c were 0.064, 0.824 and 0.112, respectively.     

NADH diaphorase as a genetic marker for sheep red cells

Three NADH diaphorase phenotypes were observed in the red cells of sheep. Breeding data indicated that this polymorphism was under the control of two autosomal co-dominant alleles, designated Dia^F and Dia^s. Phenotype Dia F had significantly lower NADH diaphorase activity than phenotype Dia S. The frzquency of Dia^F and Dia^S was determined in 9 different breeds.     

The pha gene cluster of Rhizobium meliloti involved in pH adaptation and symbiosis encodes a novel type of K+ efflux system

The fix-2 mutant of Rhizobium meliloti affected in the invasion of alfalfa root nodules (Inf⁻/Fix⁻) is K⁺ sensitive and unable to adapt to alkaline pH in the presence of K⁺. Using directed Tn 5 mutagenesis, we delimited a 6 kb genomic region in which mutations resulted in both Inf⁻/Fix⁻ and K⁺-sensitive phenotypes. In this DNA region, seven open reading frames (ORFs) were identified and the corresponding genes were designated phaA , B , C , D , E , F and G . The putative PhaABC proteins exhibit homology to the subunits of a Na⁺/H⁺ antiporter from an alkalophilic Bacillus strain. Moreover, PhaA and PhaD also show similarity to the ND5 and ND4 subunits of the proton-pumping NADH:ubiquinone oxidoreductase respectively. Computer analysis suggests that all seven proteins are highly hydrophobic with several possible transmembrane domains. Some of these domains were confirmed by generating active alkaline phosphatase fusions. Ion transport studies on phaA mutant cells revealed a defect in K⁺ efflux at alkaline pH after the addition of a membrane-permeable amine. These results suggest that the pha genes of R. meliloti encode for a novel type of K⁺ efflux system that is involved in pH adaptation and is required for the adaptation to the altered environment inside the plant.     

Polymorphism of postalbumins in the serum of pigs and the ovarian follicular fluid of sows

By means of starch-gel electrophoresis blood serum postalbumins of pigs were separated into two polymorphic regions. The first region forms a genetic system determined by two codominant alleles, Pa ₁^A and PA ₁^B. Segregation data are presented which support this hypothesis. It was found that neither sex nor age of the animal have any influence on the mobility of fractions. Identical types of blood serum postalbumins were also found in the ovarian follicle fluid.     

An additional locus controlling liver esterases of chickens

Starch gel electrophoresis of liver extracts of chickens revealed six regions, designated I to VI, of esterase activity. Three phenotypes, A, B and AB, were found in esterases in region I. These phenotypes were shown to be controlled by a pair of codominant autosomal alleles, Es -5^A and Es -5^B.