Expression of the β-subunit of β-conglycinin in seeds of transgenic plants

Soybean (Glycine max (L.) Merr.) seeds contain the storage protein -conglycinin, encoded by a multigene family. -Conglycinin consists of three subunits; , , and . A genomic clone for a -subunit of -conglycinin has been characterized by restriction-enzyme mapping and hybrid selected in-vitro translation followed by immunoprecipitation. In order to determine the developmental regulation of this -subunit gene, its expression was studied in seeds of transgenic petunia (Petunia hybrida) and tobacco (Nicotiana tabacum L.) plants. The -subunit expressed in seeds of petunia and tobacco was recognized by anti--conglycinin serum at a relative molecular mass of 53 000, equivalent to that of the native protein. Separation of the petunia-seed proteins by isoelectric focusing followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis showed that multiple isoelectric forms of the -subunit were produced. There was approximately a twofold variation in the accumulation of the -subunit protein in the mature seeds of transgenic petunia plants, each containing a single -subunit gene. However, the level of protein accumulation in mature seeds and the amount of -subunit mRNA in developing seeds was not correlated. Accumulation of the -subunit protein in transgenic seeds was less than the -subunit protein that accumulated in transgenic petunia seeds containing a single -subunit gene and less than the amount of the -subunit in mature soybean seeds which contain 8–13 -subunit genes. In transgenic tobacco plants, the accumulation of the -subunit protein in seeds was generally well correlated with the number of genes that were incorporated in the different transformants.Abbreviations kb kilobase - kDa kilodalton - M_r relative molecular mass - SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresis     

Factors Involved in Hydrolysis of Microcrystalline Cellulose by Acetivibrio cellulolyticus

Acetivibrio cellulolyticus cellulase obtained by the water elution of residual cellulose from the growth medium was compared with the cellulase activity present in culture supernatants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that water elution released most of the protein bands which adhered to undigested cellulose from the culture medium. The enzyme in the culture supernatant and that eluted from residual cellulose had specific activities for Avicel hydrolysis that were 20- to 40-fold greater than that of Trichoderma reesei cellulase. However, Ca²⁺ and a reducing agent such as dithiothreitol were required for maximum Avicel hydrolysis rates by these A. cellulolyticus enzyme preparations. The effect of these agents on p-nitrophenyl lactopyranoside hydrolysis suggested that they were required by an exoglucanase component. Supernatant enzyme preparations contained large amounts of carbohydrate which was separated from most of the cellulase protein by phenyl-Sepharose chromatography. Removal of this carbohydrate, which interfered with protein fractionations, allowed for an activity stain analysis of the supernatant enzyme.     

On the mountain top with Mr. Osterhout

George E. Osterhout, an amateur botanist, collected mainly in Colorado between 1893 and 1936. A brief account of his career and character; a list of his proposed new species and new combinations; and his bibliography.     

The metabolism of deoxyguanosine in mitochondria. Characterization of the uptake process

Summary The uptake of deoxyguanosine by rat liver mitochondria was characterized. The process required an intact mitochondrial membrane and exhibited a dependence on added phosphate. Deoxyguanosine uptake was minimally influenced by Mg²⁺ or Mn²⁺, but Ca²⁺ at concentrations above 0.5 mM were detrimental. Of the deoxynucleosides tested, only deoxyinosine inhibited the uptake of deoxyguanosine. The ribonucleoside guanosine was not observed to compete with its deoxynucleoside analog. Known inhibitors of nucleoside transport, cytochalasin B and NBMPR, did not block deoxyguanosine uptake, but the sulfhydryl reagents NEM and pCMB were both inhibitory. The uptake of deoxyguanosine was shown to be a saturable process and an apparent Km of 0.64 M was calculated from a Hanes plot.     

Depressed natural cytotoxicity but normal natural killer cytotoxic factor (NKCF) production by mononuclear cells derived from patients with hepatocellular carcinoma

Summary This study investigated the relation between the production of natural killer cytotoxic factors (NKCF) and the phenomenon of natural killing (NK) activity against target K562 cells. Two different models of defective NK cell activity were employed. In the first instance, cytotoxic activity of mononuclear cells (MN) derived from patients with hepatocellular carcinoma was compared to the ability of these cells to produce NKCF. Although direct cytotoxicity was considerably impaired in these patients, the ability of their MN to produce NKCF when stimulated with K562 cells was found to be normal. In the second model, MN treated with the lysosomotropic drug monensin showed considerably reduced direct cytotoxic activity, although they were capable of producing normal amounts of NKCF when activated by K562 cells. These results therefore indicate that there is no correlation between NK activity and corresponding NKCF release, and suggest that NKCF production and activity is independent of direct NK cytotoxic activity.     

Plant feeding of yellow baboons (Papio cynocephalus) in Mikumi national park,Tanzania, and the relationship between seasonal feeding and immature survival

Focal-animal feeding data obtained from 64 adult baboons during a 3-year period were used together with equivalent data from 46 infants to evaluate hypotheses predicting selection for a birth peak and to study the baboon’s eclectic/selective feeding adaptation, with emphasis on differential feeding by sex, developmental trends, and seasonal use of food classes (fruit, leaf, flower, grass, etc.). The findings suggest that feeding conditions are better in the wet season than in the dry season. Despite large sexual dimorphism, estimates of total amounts eaten were virtually identical for males and females. Infants used all of the same plant-food classes as adults, but proportional differences occurred for some food classes in amounts eaten. Foods eaten proportionately less by infants were probably harder for them to obtain and process or were chosen through inexperience or for exploration. There was considerable between-year variation in amounts of food classes eaten, but the within-year standard deviations were similar, as were also the mean amounts eaten per year. An eclectic/selective feeding adaptation has the advantage of permitting long-run acquisition of adequate nutrition within a context of high feeding variation from season to season and year to year. Mixed results were obtained from hypotheses about selection for a birth peak. Although a peak occurred in the early dry season, this was not the optimal time of birth for survival. Survival was highest for individuals born in the late wet season, when the availability and probably the quality of food for lactating mothers were greatest.     

Obligation and the new naturalism

Although it has become increasingly evident that an adequate theory of obligation must rest on evolutionary biology and human ethology, attempts toward this end need to explore the full range of personal, cultural, and political obligations observed in our species. The new naturalism reveals the complexity of social behavior and the defects of reductionist models that oversimplify the foundations of human duties and rights. Ultimately, this approach suggest a return to the Aristotelian concept of natural justice.     

Purinergic modulation of cardiac activity in the flounder during hypoxic stress

Summary The interaction of adrenaline and adenosine was examined in cardiac tissue of the flounderPlatichthys flesus.When applied alone both agents increased contractility in both auricular and ventricular myocardial strips. This positive inotropic effect was associated with a small depolarization in the tissues examined by the sucrose gap technique. Simultaneous application of adrenaline and adenosine gave an inhibition of the control responses seen with either agent alone in both auricle and ventricle.Radiocalcium flux studies on ventricular tissue showed that influx was increased by adrenaline or adenosine alone above control values, but when applied together radiocalcium influx was reduced. Radiocalcium efflux from cardiac microsomes was stimulated by challenge with adrenaline or adenosine alone. This stimulation was not seen following simultaneous challenge by both agents.The effect of adrenaline on responses of hypoxic flounder hearts was less than that seen in normoxic hearts. This situation was reversed by pretreatment with the purine receptor blocker caffeine. Caffeine pretreatment also reduced the positive inotropic effect seen in normoxic hearts challenged with adenosine.TLC studies gave strong evidence that hearts perfused with hypoxic salines produced both adenosine and adrenaline.The results are discussed as evidence for a mechanism of heart regulation which the flounder may use as a defence against severe acute hypoxic stress.