The Electrical Conductivity of Bovine Milk in Mastitis Diagnosis

The electrical conductivity (EC) of milk is mainly a function of the electrolyte concentration in the milk and therefore raised in mastitis. The present investigation was aimed at elaborating, if possible, a diagnostic model for screening purposes based on EC determinations and consistent with the diagnostic procedures and interpretations commonly used in laboratory milk diagnosis in the Nordic countries (Klastrup 1975). According to this diagnosis (here called reference diagnosis) cell numbers above 300,000/ml (cell count or the corresponding CMT-score) in foremilk quarter samples during the main part of the lactation period and significantly above the lowest value on within-udder comparison during late lactation are considered indicative of mastitis and bacteriological examinations are made when called for.     

Autophosphorylation of type 2 casein kinase TS at both its α- and β-subunits: Influence of different effectors

Rat liver casein kinase TS (Ck-TS) having quarternary structure α₂β₂, autophosphorylates at its 25 kDa, β-subunits, incorporating up to 1.2 mol P/mol enzyme. According to their effects on the autophosphorylation pattern the effectors of Ck-TS activity can be grouped into 3 classes: (i) inhibitors, like heparin, which also prevent the autophosphorylation of the β-subunit; (ii) stimulators possessing several amino groups (like spermine) which increase the autophosphorylation at the β-subunit; (iii) stimulators possessing several guanido groups, like protamines and related peptides, which prevent the phosphorylation of the β-subunit, while promoting the autophosphorylation of the 38 kDa α-subunit. In the presence of such polyarginyl effectors the 130 kDa Ck-TS is converted into forms with higher sedimentation coefficient.     

Morphological variation of Keratella cochlearis (Gosse) in Lake Biwa,Japan

The length of the lorica (LL) of Keratella cochlearis cochlearis and of K. cochlearis tecta and the length of posterior spine (PSL) of the latter morphotype were measured in the strongly eutrophic basin and also in the mesotrophic basin of Lake Biwa, Japan, from September to December, 1980. In the population from the mesotrophic basin, the individuals with longer PSL prevail and the tecta forms are extremely rare. The LL values of both morphotypes from one sample do not differ. In December the LL increased to 95 µm in both morphotypes from 80 µm observed in September, while the PSL values decreased abrubtly in both basins in the middle of this period. It is suggested that the observed increase of LL could be related to the thermic factor, i.e. a steady decrease of water temperature, and the changes of PSL are correlated with the increase of nannoplankton and detritus aggregates noted in November. In this month an increase in fecundity and in the total numbers of rotifers took place as well (Hillbricht-Ilkowska, in press).     

Comparison of various atmospheric conditions for isolation and subcultivation of Mycoplasma hyorhinis from cell cultures

The efficiency of aerobic incubation was compared with incubation under various oxygen and carbon dioxide conditions for the isolation and subcultivation of three strains of Mycoplasma hyorhinis from VERO-cell cultures and subcultivation of three laboratory strains. Under anaerobic conditions with a low oxidation-reduction potential (at or below -115 mV) as obtained in jars, with catalysts, containing mixtures of 5%-10% CO2 in H2, very poor or no growth of any of the six M. hyorhinis strains was observed. When traces of oxygen were present (that is, under conditions with higher oxidation-reduction potentials, e.g. when omitting the catalyst in the above gas mixtures or in 5% CO2 + 95% N2) isolation from cell cultures was successful in most tests, but subcultivation of these primary isolates was seldom possible under these semi-anaerobic conditions. However, in most cases these primary isolates could be subcultivated aerobically, although aerobic conditions were unsatisfactory for isolation in about half of the experiments. Isolation of M. hyorhinis was optimal in 5% O2 + 95% N2, under which condition the isolates could also always be subcultivated. Isolation failed occasionally when 5% O2 + 5% CO2 + 90% N2 was used, thus indicating that 5% CO2 was slightly inhibitory. 5% CO2 in air and 10% CO2 either in air, H2 or N2 were also inadequate for isolation from cell cultures. In contrast to the findings with these cell culture-adapted M. hyorhinis strains, the laboratory strains could be subcultivated easily under all conditions tested except those with an oxidation-reduction potential at or below -115 mV; 100% CO2 was inhibitory for all 6 strains. Our findings may partly explain why M. hyorhinis is often considered "non-cultivable" on artificial media once adapted to cell cultures. The findings emphasize the need to employ also a micro-aerophilic condition (5% O2 in 95% N2) in the examination of cell cultures for mycoplasma.     

Different structure of polytene chromosomes ofPhaseolus coccineus suspensors during early embryogenesis

Summary The pattern of DNA and RNA puffs in pair VII of polytene chromosomes has been investigated in the suspensor ofPhaseolus coccineus during early embryo development. The pattern of³H-TdR and³H-U incorporation has been also detected. Collected data indicate that: 1. both heterochromatic regions, p₁₁ and q_(111+112), of chromosome pair VII, organize large DNA puffs; 2. DNA puffs of both regions are specific of different embryo differentiation steps; 3. a seasonal influence on the DNA puffing seems also to be present, as demonstrated by the comparison of the results collected in two different crops; 4. the incorporation experiment by³H-TdR evidences that not all DNA puffs show clustered labeling; 5. the RNA puffing of the two regions seems also to be specific of determined embryo stages.     

Action of two juvenile hormone antagonists on lepidopteran epidermis

The juvenile hormone antagonist ETB (ethyl-4-2(t-butylcarbonyloxy)-butoxybenzoate) caused formation of precocious larval-pupal intermediates after the 4th (penultimate)-larval instar of the tobacco hornworm, Manduca sexta, when 50 μg were applied to any 3rd stage larvae or to 4th stage larvae within 12 hr after ecdysis. This dose was most effective within 12 hr after ecdysis to the 3rd stage. In the black mutant larval assay for juvenile hormone, ETB had activity, 0.75 μg per larva giving half-maximal score. In vitro ETB acted as a juvenile hormone to prevent the ecdysteroid-induced change in commitment at concentrations above 0.1 μg/ml with an ED₅₀ at 2.8 μg/ml and as a partial juvenile hormone antagonist to 0.1 μg/ml juvenile hormone I at concentrations between 10^?3 and 10^?2 μg/ml. By contrast, EMD (ethyl-E-3-methyl-2-dodecenoate) had little juvenile hormone-like activity in vitro up to its limits of solubility (100 μg/ml) and exhibited sporadic partial juvenile hormone antagonistic activity in vitro at concentrations between 1 and 100 μg/ml. Since these concentrations were 10–1000 times that of juvenile hormone I in the medium, EMD apparently is not an efficient competitor.     

Translation of poly(U) on ribosomes from Streptomyces aureofaciens

Slowly cooled cells of Streptomyces aureofaciens contained mainly tight-couple ribosomes. Maximum rate of polyphenylalanine synthesis on ribosomes of S. aureofaciens was observed at 40°C, while cultures grew optimally at 28°C. Ribosomes of S. aureofaciens differed from those of E. coli in the amount of poly(U) required for maximum synthetic activity. The polyphenylalanine-synthesizing activity of E. coli ribosomes was about 3-times higher than that of S. aureofaciens ribosomes. The addition of protein S1 of E. coli or the homologous protein from S. aureofaciens had no stimulatory effect on the translation of poly(U). In order to localize alteration(s) of S. aureofaciens ribosomes in the elongation step of polypeptide synthesis we developed an in vitro system derived from purified elongation factors and ribosomal subunits. The enzymatic binding of Phe-tRNA to ribosomes of S. aureofaciens was significantly lower than the binding to ribosomes of E. coli. This alteration was mainly connected with the function of S. aureofaciens 50 S subunits. These subunits were not deficient in their ability to associate with 30 S subunits or with protein SL5 which is homologous to L7/L12 of E. coli.     

Bemerkungen zur Taxonomie vonVicia sepium L.

In der ArtVicia sepium L. kann man in Mitteleuropa und in südlichen Teilen von Nordeuropa drei Varietäten unterscheiden: 1. var.sepium mit breiten Blättchen und einem kahlen bis angedrückt behaarten Kelch, 2. var.montana Koch mit schmalen Blättchen und einem kahlen oder zerstreut angedrückt behaarten Kelch, und 3. var.eriocalyx ?elak. mit breiten bis mittelbreiten Blättchen und einem abstehend langbehaarten Kelch, noch mit einer niedrigen und einer hohen Wuchsform. Bei allen Proben wurde die Chromosomezahl 2n=14 festgestellt.