An Integrated Technique for the Analysis of Skin Bite Marks

The high number of murder, rape, and child abuse cases in South Africa has led to increased numbers of bite mark cases being heard in high courts. Objective analysis to match perpetrators to bite marks at crime scenes must be able to withstand vigorous cross-examination to be of value in conviction of perpetrators. An analysis technique is described in four stages, namely determination of the mark to be a human bite mark, pattern association analysis, metric analysis and comparison with the population data, and illustrated by a real case study. New and accepted techniques are combined to determine the likelihood ratio of guilt expressed as one of a range of conclusions described in the paper. Each stage of the analysis adds to the confirmation (or rejection) of concordance between the dental features present on the victim and the dentition of the suspect. The results illustrate identification to a high degree of certainty

N-(18-hydroxylinolenoyl)-L-glutamine: a newly discovered analog of volicitin in Manduca sexta and its elicitor activity in plants.

Plants attacked by insect herbivores release a blend of volatile organic compounds (VOCs) that serve as chemical cues for host location by parasitic wasps, natural enemies of the herbivores. Volicitin, N-(17-hydroxylinolenoyl)-L-glutamine, is one of the most active VOC elicitors found in herbivore regurgitants. Our previous study revealed that hydroxylation on the 17th position of the linolenic acid moiety of N-linolenoyl-L-glutamine increases by more than three times the elicitor activity in corn plants. Here, we identified N-(18-hydroxylinolenoyl)-L-glutamine (18OH-volicitin) from larval gut contents of tobacco hornworm (THW), Manduca sexta. Eggplant and tobacco, two solanaceous host plants of THW larvae, and corn, a non-host plant, responded differently to this new elicitor. Eggplant and tobacco seedlings emitted twice the amount of VOCs when 18OH-volicitin was applied to damaged leaf surfaces compared to N-linolenoyl-L-glutamine, while both these fatty acid amino acid conjugates (FACs) elicited a similar response in corn seedlings. In both solanaceous plants, there was no significant difference in the elicitor activity of 17OH- and 18OH-volicitin. Interestingly, other lepidopteran species that have 17OH-type volicitin also attack solanaceous plants. These data suggest that plants have developed herbivory-detection systems customized to their herbivorous enemies

Plant volatile eliciting FACs in lepidopteran caterpillars, fruit flies, and crickets: a convergent evolution or phylogenetic inheritance?

Fatty acid amino acid conjugates (FACs), first identified in lepidopteran caterpillar spit as elicitors of plant volatile emission, also have been reported as major components in gut tracts of Drosophila melanogaster and cricket Teleogryllus taiwanemma. The profile of FAC analogs in these two insects was similar to that of tobacco hornworm Manduca sexta, showing glutamic acid conjugates predominantly over glutamine conjugates. The physiological function of FACs is presumably to enhance nitrogen assimilation in Spodoptera litura larvae, but in other insects it is totally unknown. Whether these insects share a common synthetic mechanism of FACs is also unclear. In this study, the biosynthesis of FACs was examined in vitro in five lepidopteran species (M. sexta, Cephonodes hylas, silkworm, S. litura, and Mythimna separata), fruit fly larvae and T. taiwanemma. The fresh midgut tissues of all of the tested insects showed the ability to synthesize glutamine conjugates in vitro when incubated with glutamine and sodium linolenate. Such direct conjugation was also observed for glutamic acid conjugates in all the insects but the product amount was very small and did not reflect the in vivo FAC patterns in each species. In fruit fly larvae, the predominance of glutamic acid conjugates could be explained by a shortage of substrate glutamine in midgut tissues, and in M. sexta, a rapid hydrolysis of glutamine conjugates has been reported. In crickets, we found an additional unique biosynthetic pathway for glutamic acid conjugates. T. taiwanemma converted glutamine conjugates to glutamic acid conjugates by deaminating the side chain of the glutamine moiety. Considering these findings together with previous results, a possibility that FACs in these insects are results of convergent evolution cannot be ruled out, but it is more likely that the ancestral insects had the glutamine conjugates and crickets and other insects developed glutamic acid conjugates in a different way

Dental arch form in three Pacific populations: a comparison with Japanese and Australian Aboriginal samples

The purpose of this study was to provide information about arch shape variations among South Pacific populations. The application of Fourier transforms, Y(øi) = ao/2 + Ʃ(aicos øi + bisin øi) was used to separate two components of variation; size and shape. Dental arch size can be described by one coefficient (ao), while the shape can be summarized by the first three harmonics (amp1-3) in the Fourier series. The materials used in this study were dental casts of South Pacific populations (Fiji, Western Samoa and Kiribati), Australian Aboriginals and Japanese. Fijians, Western Samoans and Kiribati people have larger upper and lower dental arches than that of Japanese. These populations were separated by the arch size and first Fourier amplitudes which showed the arch depth/width ratio. The Fijian upper and lower dental arches were significantly larger than those found in other populations and was characterised by a wide posterior arch breadth. The Western Samoan and Kiribati arch shape was more similar to the Japanese arch shape than the Fijian. Distribution patterns of arch shape characteristics in these populations showed the same tendencies in the upper and lower arches

Active role of fatty acid amino acid conjugates in nitrogen metabolism in Spodoptera litura larvae

Since the first fatty acid amino acid conjugate (FAC) was isolated from regurgitant of Spodoptera exigua larvae in 1997 [volicitin: N-(17-hydroxylinolenoyl)-l-glutamine], their role as elicitors of induced responses in plants has been well documented. However, studies of the biosyntheses and the physiological role of FACs in the insect have been minimal. By using 14C-labeled glutamine, glutamic acid, and linolenic acid in feeding studies of Spodoptera litura larvae, combined with tissue analyses, we found glutamine in the midgut cells to be a major source for biosynthesis of FACs. Furthermore, 20% of the glutamine moiety of FACs was derived from glutamic acid and ammonia through enzymatic reaction of glutamine synthetase (GS). To determine whether FACs improve GS productivity, we studied nitrogen assimilation efficiency of S. litura larvae fed on artificial diets containing 15NH4Cl and glutamic acid. When the diet was enriched with linolenic acid, the nitrogen assimilation efficiency improved from 40% to >60%. In the lumen, the biosynthesized FACs are hydrolyzed to fatty acids and glutamine, which are reabsorbed into tissues and hemolymph. These results strongly suggested that FACs play an active role in nitrogen assimilation in Lepidoptera larva and that glutamine containing FACs in the gut lumen may function as a form of storage of glutamine, a key compound of nitrogen metabolism