Description of the immatures of Linepithema humile Mayr (Hymenoptera: Formicidae)

Linepithema humile Mayr is an ant species originally native to South America that has been spread accidently throughout the globe through international trade. It is a serious urban and crop pest. Despite its economic importance, little is known about the larvae of this species apart from a brief description based on a few specimens. The present investigation is aimed at describing every immature stage of L. humile. Three larval instars were determined through the frequency distribution of the maximum width of head capsules from a sample of 525 larvae. The morphological descriptions were based on 150 eggs, 70 larvae, and 90 pupae examined by light and scanning electron microscopy. Some morphological characteristics reported to be typical of Linepithema Mayr larvae were confirmed--dolichoderoid body shape, presence of dorsal protuberance, sparse simple body hairs, presence of nine pairs of spiracles and dolichoderoid mandibles. We concluded that an earlier published description was based on queen larvae, and that the protuberance is only present in worker larvae. The information provided in this study may aid ant systematics and phylogenetics, as well provide a better understanding of the biology of this species.

New Nicoletiidae (Zygentoma: Insecta) from Brazil living in fire-ant (Hymenoptera: Insecta) nests

A new myrmecophilous silverfish (Zygentoma: Nicoletiidae: Subnicoletiinae) from Rio de Janeiro, Brazil, found living in fire ant (Solenopsis saevissima, Formicidae: Myrmicinae) nests is described: Allotrichotriura saevissima gen. nov. sp. nov. is compared with the other genera and subgenera known in the subfamily. The main diagnostic features would include the combination of body shape, body and head setation, morphology of praetarsus, and number of abdominal stylets and vesicles. Although further quests were attempted at the type-locality, only the original described material, exclusively composed of females, remains known.

HLA Is Not Predictive of Posttransplant Diabetes Mellitus

AIMS

New-onset posttransplant diabetes mellitus (PTDM) is a frequent complication of kidney transplantation. The goal of this study was to identify if the tendency to develop PTDM was associated to the HLA, as is seen in the general population.

METHODS

A retrospective study was made of 525 patients who underwent renal transplantation between 1997 and 2004. They were divided into three categories depending on the diabetic status before and after kidney transplantation. The HLA profile of each patient was identified for class 1 and class 2 antigens including HLA-A, HLA-B, and DR-R. Antigen frequencies were calculated and gene frequencies derived. These were compared among the three groups and with the published data for the Puerto Rico population. Other variables studied included weight, age, gender, and family history.

RESULTS

Seventy-two of 526 (13.7%) were diabetic before transplantation; 92/453 (20.3%) developed PTDM after kidney transplantation. Pretransplant diabetics showed a higher incidence of A3 (0.1102 vs 0.0869 vs 0.0361), DR4 (0.3334 vs 0.1932 vs 0.2124), and DR-13 (0.1835 vs 0.1115 vs 0.1175) than nondiabetics and the normal Puerto Rican population. Posttransplant diabetics showed a higher A3 (0.1154) and a higher DR3 (0.0675 vs 0.0295 vs 0.0022) than nondiabetics and normal population.

CONCLUSION

PTDM was not associated statistically with the HLA in this group of transplant recipients, although A3 and DR3 were higher. Patients with the phenotype that is related to diabetes in the normal population did not have a higher incidence of diabetes in this series.

Effect of low-dose gamma irradiation on Staphylococcus aureus and product packaging in ready-to-eat ham and cheese sandwiches

Staphylococcus aureus is a common pathogen that causes foodborne illness. Traditional methods for controlling S. aureus do not address postprocess contamination. Low-dose gamma irradiation is effective in reducing pathogens in a variety of foods and may be effective in reducing S. aureus in ready-to-eat foods. The effects of gamma irradiation on product packaging should also be considered. The objective of this study was to determine the effects of gamna irradiation on product packaging and on S. aureus in ready-to-eat ham and cheese sandwiches. The effects of refrigerated storage on irradiated and nonirradiated sandwiches were also investigated. Ham and cheese sandwiches were inoculated with 10(6) or 10(7) CFU of S. aureus per g, frozen, irradiated, and analyzed by a standard plate count method. D10-values, the amount of irradiation needed to elicit a 1-log10 reduction of bacteria, were calculated. In addition, irradiated sandwiches were analyzed after 1, 13, 27, and 39 days of storage at 4 degrees C. The integrity of postirradiated packaging material was analyzed using Fourier transform infrared (FTIR) spectroscopy. Two experiments yielded D10-values of 0.62 and 0.63. During refrigerated storage, sandwiches irradiated with 5.9 kGy showed no S. aureus growth at any time; sandwiches irradiated with 3.85 kGy showed a 6.18-log reduction in S. aureus after 13 days; and nonirradiated sandwiches showed a 0.53-log increase in S. aureus after 39 days. FTIR spectroscopy showed that the label side and the bulge side were composed of polyethylene terephthalate and nylon 6, respectively. No significant change in the packaging due to irradiation was detected. In this study, low-dose gamma irradiation was shown to be an effective method for reducing S. aureus in ready-to-eat ham and cheese sandwiches and proved to be more efficacious than refrigeration alone. Additionally, package integrity was not adversely affected by gamma irradiation.