Murray S. Blum

10-Hydroxy-Δ2-Decenoic Acid, an Antibiotic Found in Royal Jelly

10-Hydroxy-Δ2-decenoic acid, the major component of the lipide fraction of royal jelly, exhibits antibiotic activity against many bacteria and fungi. This fatty acid is less than one-fourth as active as penicillin against Micrococcus pyogenes and less than one-fifth as active as chlortetracycline against Escherichia coli. It also slows the growth rate of Neurospora sitophila and some unidentified molds. The salt of this compound is considerably less active than the free acid.

Trail Marking Substance of the Texas Leaf-Cutting Ant: Source and Potency

The trail-marking substance of Atta texana (Buckley) is formed in the true poison gland and deposited by the sting. This attractant is initially produced by teneral workers. The substance obtained from mature, large workers is the most potent.

Chemical releasers of social behaviour—V. Source, specificity, and properties of the odour trail pheromone of Tetramorium guineense (F.) (Formicidae: Myrmicinae)☆

Abstract The source of the odour trail pheromones of Tetramorium guineense (F.) and T. caespitum (L.) is the true poison gland. Neither species of Tetramorium will follow each others artificial odour trails. On the other hand, T. guineense follows artificial odour trails prepared from the poison glands of two attines, Trachymyrmex septentrionalis (McCook) and Atta texana (Buckley) and vice versa. The poison gland of T. guineense is a rich source of free amino acids, and the odour trail pheromone is a trace constitutent of the venom. This pheromone is a relatively stable compound with a low vapour pressure. Based on its solubility characteristics, it appears to be a fairly short-chain mono-functional compound whose chemical properties would not be inconsistent with those of an alcohol. The ability of different myrmicine genera to draw from the common constituents of the poison gland for their odour trail pheromones probably explains why the myrmicine poison gland extracts lack species specificity.

Secretion of Benzaldehyde and Hydrogen Cyanide by the Millipede Pachydesmus crassicutis (Wood)

The millipede Pachydesmus crassicutis (Wood) secretes a mixture of benzaldehyde and hydrogen cyanide when it is disturbed. These compounds are secreted through paired glands located on 11 of the notal projections of adult millipedes. Experiments with the imported fire ant demonstrate that these natural products serve a defensive function.

Preservation of Honey Bee Semen

Fertilized eggs have been obtained from queen honey bees (Apis mellifera L.) inseminated with sperm that had been stored in vitro at above-freezing temperatures for up to 68 days. The effects of various experimental storage treatments on semen are described. Semen shipped by ordinary mail has been successfully used for artificial insemination.

Chemical releasers of social behaviour—VI. The relation of structure to activity of ketones as releasers of alarm for Iridomyrmex pruinosus (Roger)☆

Abstract 2-Heptanone, the alarm pheromone produced by Iridomyrmex pruinosus, is a powerful attractant for workers of this dolichoderine species. I. pruinosus also appears to employ this alarm pheromone for defense. The possible origin of alarm pheromones from defensive secretions is discussed. The abilities of 49 ketones to produce typical alarm behaviour in I. pruinosus were determined in order to establish the relationship between chemical structure and alarm-releasing activity. Ketones in the range C3 to C13 were tested on both laboratory and strong field colonies. In the series of 2-alkanones, activity was present in the C5 to C10 ketones, the most pronounced activity occurring in the range C6 to C9. The corresponding cycloalkanones showed no activity. In general, movement of the carbonyl group toward the centre of the hydrocarbon chain caused at least a slight diminution in activity. The introduction of a second carbonyl group either had no effect or produced a slight drop in the ability of the compound to release alarm. Unsaturation in the aliphatic chain either slightly increased or did not alter the activity of the synthetic pheromones. Branched methyl groups produced compounds which were generally less active than their unbranched isomeric counterparts, although this relationship was not absolute, especially in the C7 to C9 ketones. Activity was also present in some phenyl alkyl ketones, which suggests that the aromatic ring can correspond to an aliphatic portion of an alkanone. These results are discussed in terms of the absolute structural requirements of a maximally active alarm pheromone for I. pruinosus. The data demonstrate that alarm releasers, in common with other types of pheromones, require a degree of structural specificity in order to manifest maximum activity.

Composition and possible significance of fatty acids in the lipid classes in honey bee semen

Abstract Phospholipids constitute the major fraction present in the lipids of honey bee semen. The neutral lipids appear to be composed primarily of triglycerides, sterols, sterol esters, and free fatty acids. The extractable seminal lipids are virtually restricted to the spermatozoa, the plasma containing only traces of detectable lipid. In all lipid classes, C16:0 and C18:0 are the main saturated fatty acids. Among the unsaturates, C18:1 is a major component in all classes and C16:1 is one of the main constituents in all fractions except the phospholipids in which it occurs in trace amounts. In the triglycerides, C18:2 is the major unsaturate. The phospholipids contain no appreciable quantities of short-chain fatty acids and C16:0 (23 per cent) and C18:1 (56 per cent) account for 80 per cent of the total fatty acids. The C18 fatty acids constitute about 50 per cent of the total fatty acids present in the triglycerides. The free fatty acid fraction contains about 27 per cent short-chain fatty acids up to C14:1. The sterol ester fraction is almost totally lacking in short-chain fatty acids but is distinguished from all other lipid classes in containing a large percentage of fatty acids with a chain length greater than C18:3. The spermatozoa of the honey bee are highly motile for several hours in the absence of added oxidizable substrate, and the concentration of phospholipids decreases during aerobic incubation. The implications of these results are discussed.

Chemical releasers of social behaviour—I. Methyl-n-amyl ketone in Iridomyrmex pruinosus (Roger) (Formicidae: Dolichoderinae)

Abstract The secretion from the anal glands of the dolichoderine Iridomyrmex pruinosus (Roger) consists primarily of methyl- n -amyl ketone. This carbonyl compound functions as a releaser of alarm in this species.

n-Tridecane and trans-2-Heptenal in Scent Gland of the Rice Stink Bug Oebalus pugnax (F.)

The scent-gland secretion of the rice stink bug Oebalus pugnax (F.) is composed of a liquid two-phase system. The saturated hydrocarbon n-tridecane accounts for 60 percent of the secretion. In the other phase, the major organoleptic compound is the trans form of 2-heptenal.

Chemistry of the drone honey bee reproductive system—III. Dehydrogenases in washed spermatozoa

Abstract The activities of thirteen dehydrogenases in washed honey bee spermatozoa from individual ejaculates were determined by employing three tetrazolum salts as artificial electron acceptors. Virtually all endogenous activity could be removed by freezing the spermatozoa in tris buffer prior to incubating the sperm cells in a reaction mixture fortified with added substrates. Honey bee spermatozoa contain high titres of the pyridine nucleotide diaphorases, NADH 2 dehydrogenase, and NADPH 2 dehydrogenase. The Krebs cycle is highly functional in the washed sperm cells, as evidenced by the active utilization of three intermediates of this energy-yielding pathway. A high titre of succinate dehydrogenase is present, whereas malate dehydrogenase is less active. The activities of both NADP- and NAD-linked isocitrate dehydrogenases are demonstrable, the former enzyme being the more active of the two. Glycolysis is very well developed in the spermatozoa as reflected by the presence of a very high level of α-glycerophosphate dehydrogenase, as well as lactate and alcohol dehydrogenases. A highly active α-glycerophosphate dehydrogenase flavoprotein is also present. Glutamate dehydrogenase is present at an intermediate activity level. No utilization of β-hydroxybutyrate occurred and glucose-6-phosphate was only slightly oxidized by the spermatozoa. The results with specific inhibitors demonstrated that the dehydrogenases of honey bee spermatozoa were generally typical in their responses with the exception of succinate dehydrogenase which was not inhibited by iodoacetate. The significance of the demonstrated dehydrogenases is discussed especially with reference to metabolic pathways which may be stressed during the long term storage of the spermatozoa in the spermatheca.