Production and characterization of polyclonal and monoclonal antibodies against Aflatoxin B1 oxime-BSA in an enzyme-linked immunosorbent assay

From a single aflatoxin B₁ oxime — bovine serum albumin conjugate, polyclonal and monoclonal antibody preparations were produced. The four rabbit polyclonal antisera were specific for aflatoxin Bi in a microtitration plate enzyme — linked immunosorbent assay. The monoclonal antibodies showed a wide range of differing specificities, recognizing, for example, aflatoxins B₁, B₂, G₁ and G₂; B₁ and B₂; B₁ and G₁; and G₁ alone. No antibody preparations reacted with aflatoxin M₁. The significance of these results to the strategy of anti-aflatoxin antibody production for use in quantitative enzyme immunoassays is discussed.     

Direct embryogenesis from single mesophyll protoplasts in alfalfa (Medicago sativa L.)

Summary We used a tetraploid clone derived from an anther culture operation of Ladak alfalfa to study the pathway of direct embryogenesis from leaf-mesophyll protoplasts. About 72% of the protoplasts divided, and 7% of those produced proembryos. Approximately 38% of the proembryos developed into green embryos, and 33% initiated calluses. Other proembryos dedifferentiated into calluses which later redifferentiated embryos. Sixteen percent of the embryos developed directly into plants, whereas 81% produced plants indirectly via secondary embryos. The remaining 3% of the primary embryos failed to develop into plants. The lowest plating efficiency for direct embryogenesis was 0.3%. The high percentage of direct embryogenesis observed was related to the genetic nature of the clone, low density of liquid medium, low protoplast culture density, and the composition of culture media.Contribution no. 90-61-J from the Kansas Agricultural Experiment Station.     

Report and characterization of a new variant, EB, of human red cell acid phosphatase.

A new variant phenotype of human red cell acid phosphatase, designated EB, was discovered in a male during a survey of blood donors from Copenhagen, Denmark. Electrophoretically, the variant revealed the two isozymes corresponding to the B type as well as two fast moving anodic isozymes. The enzyme activity and thermostability were found to be higher than in any earlier reported type. Isoelectric focusing of the variant type indicated that the isoelectric point of the variant enzyme is lower than in the common types.     

Identification of glutathione S-transferase Yb1 mRNA as the androgen-repressed mRNA by cDNA cloning and sequence analysis

Androgens, while stimulating the growth of the rat ventral prostate, can also repress the levels of a limited number of mRNAs. The cDNA for one of the androgen-repressed mRNAs has been identified by nucleotide sequence analysis as coding for the glutathione S-transferase Yb1 subunit. The prostate cDNA is 1071 nucleotides long, and only 2 or 4 bases of this sequence do not match the two published sequences of the cDNA for the Yb1 subunit of rat liver glutathione S-transferase. The amino acids in the protein encoded by the prostate cDNA matched completely with that for one of the liver cDNAs and differ with the other cDNA only in two of 218 amino acids. The identification of the androgen-repressed mRNA as a glutathione S-transferase subunit may indicate that some of the cellular actions of the enzyme may be important in the control of androgen-dependent growth of the prostate. Since Yb forms of the transferases have been colocalized with uridylic acid-rich small nuclear RNAs at interchromatinic regions of the cell nucleus, autoregulation of prostate growth by androgens may be carried out through the modulation of RNA production or processing in this target organ.     

Taste aversion and frugivore preference

Summary I tested the hypothesis that thrushes avoid certain species of fruits because of their taste. It was found that thrushes had significant preferences and aversions for the flavours of certain species of fruit. Several species of fruit which thrushes avoided contained identified toxins. It is speculated that some species of plants have evolved fruit toxins to prevent thrushes from consuming fruits and dispersing seeds to unfavourable habitats.     

Lymphocyte responses of human neonates to bacterial antigens

Human lymphoid lines derived from normal or neoplastic B cells were assayed for insulin binding. ¹²⁵I-Labeled insulin was allowed to bind to cells. Bound radioactivity which was inhibited with unlabeled insulin was regarded as specific binding. Among 46 lines tested, 43 bound more insulin than normal peripheral B lymphocytes. The majority of the lines resembled activated lymphocytes, with regard to their insulin binding. More mature cells represented by EBV-transformed lines of normal origin, bound more insulin than the less differentiated Burkitt lymphoma lines. However, even the latter bound significantly more insulin than peripheral blood lymphocytes.     

The induction of maturation and ovulation in American eels, Anguilla rostrata (LeSueur), and the relevance of chemical and visual cues to male spawning behaviour

Female American eels, Anguilla rostrata (LeSueur), were artificially matured with injections of salmon and carp pituitary and human chorionic gonadotropin. In vivo ovulation was induced with 4-pregnene-17α,20β-diol-3-one and eggs were spontaneously released. Eggs were fertilized in vitro and survived to the gastrula stage. Males were matured with injections of human chorionic gonadotropin. They were attracted by the sight and odour of maturing and mature females. Ovulated females released a sex pheromone which was especially attractive to mature males and triggered the release of sperm.