Increased allocation of adult-acquired carbohydrate to egg production results in its decreased allocation to sex pheromone production in mated females of the moth Heliothis virescens.

Females of most species of moths produce a volatile sex pheromone that attracts conspecific males over distance. In females of the polyandrous moth Heliothis virescens, feeding on carbohydrate (e.g. nectar) supplies precursor, via hemolymph trehalose, for both sex pheromone and egg production. With limited carbohydrate acquisition these two reproductive physiologies might compete for hemolymph trehalose, resulting in an allocation deficit to either sex pheromone or egg production. Using virgin and mated females, which have low and high egg maturation rates, respectively, we fed females a limited diet of (13)C-labeled glucose daily and, using mass isotopomer distribution analysis, determined allocations of adult-acquired carbohydrate (AAC) to newly synthesized pheromone and ovarian and egg fats, our proxies for allocation to egg production. With increased number of feeds, AAC enrichment of hemolymph trehalose increased, as expected. This led to mated females increasing their proportional allocation of AAC to ovarian and egg fats, but decreasing their proportional allocation of AAC to pheromone production. By contrast, virgins increased their proportional allocation of AAC to pheromone production with increased feeds, consistent with increasing AAC enrichment of hemolymph trehalose. These results show that with limited AAC intake, enhanced egg maturation in mated females results in reduced AAC allocation to pheromone production; this does not occur in virgins because of their lower egg maturation rate. This physiological competition for AAC corresponded with decreased pheromone production in mated moths to levels unlikely to attract mates. Therefore, the availability and/or allocation of AAC may be a proximate mechanism underlying the incidence of polyandry in this and other species of moths.

Factors contributing to the poor performance of a soybean aphid parasitoid Binodoxys communis (Hymenoptera: Braconidae) on an herbivore resistant soybean cultivar.

Host plant resistance and biological control are important components of integrated pest management programs. However, plants expressing resistance to herbivores may also have direct or indirect negative effects on natural enemies simultaneously providing pest suppression. Soybean aphids (Aphis glycines Matsumura) are invasive and serious pests of soybean (Glycine max L.) in the United States. Several soybean lines with aphid resistance have been identified, but the long-term impact of these resistant plants on soybean aphid biological control agents is uncertain. In a previous study, we reported that a soybean aphid parasitoid, Binodoxys communis (Gahan) had lower mummy production on resistant plants compared with a near isogenic susceptible soybean line, but the reason for this was unclear. Therefore, we examined three possible mechanisms to explain these findings: 1) resistant plants directly impact wasp emergence and longevity, 2) varying aphid density influences parasitism rates, and 3) resistant plants indirectly affect wasp development through reduced aphid longevity. We found that parasitoids in this study were not directly influenced by resistant cultivars, as there was no difference in wasp adult emergence or longevity between resistant and susceptible plants. There was also no significant effect of aphid density on mummy production over the range of aphid densities we tested. However, aphids on resistant plants had significantly shorter lifespans and were unable to survive long enough to develop into mummies compared with aphids on susceptible plants. We discuss these results and possible implications for integrating biological control and host plant resistance within soybean aphid integrated pest management programs.

In-situ synthesis and performance of titanium oxide/poly(methyl methacrylate) nanocomposites.

Polymer nanocomposites have elicited extensive research efforts due to their potential to exhibit spectacular properties. They have immense potential and are befitting materials to serve as an ideal and futuristic alternative for varied applications. Poly(methyl methacrylate) (PMMA) and titanium oxide (TiO2) nanocomposites used in this study were fabricated by an in-situ free radical polymerization process. Three point bend tests were conducted with a modified universal microtribometer to evaluate fracture toughness. The results indicated that the stress intensity values increase as the concentration of titanium oxide increases up to 1 vol% and subsequently decrease at higher concentrations. Scanning electron microscopy (SEM) images of fracture surfaces afforded clues as to the possible deformation mechanism. Ultraviolet-visible spectroscopy (UV-vis) evaluated the degree of transparency of the nanocomposites. It was observed that samples became opaque as the concentration was increased beyond 0.01% volume fraction. X-ray diffraction characterized the TiO2 crystalline phase and Scherrer's equation was used to calculate the crystallite size. Among the concentrations considered the 3% volume fraction sample had the largest crystallite size. Finally, microhardness measurements further characterized the mechanical properties of the composites.

Vascular embolization of benign granulosa cells.

OBJECTIVE(S): Most conditions involving sex cord-stromal cells can be diagnosed on morphologic criteria alone. We describe a case of vascular embolization of benign granulosa cells in which immunohistochemistry was of value as a diagnostic tool. METHODS: We reviewed the clinical history and gross pathologic findings from a 48-year-old patient who presented with abdominal pain and fullness. Formalin-fixed paraffin-embedded sections were examined by routine H&E and immunohistochemical stains. RESULTS: Histologic examination of a grossly enlarged and cystic ovary revealed nests of cells within angiolymphatic spaces. Although the cells were cohesive and atypical, they were morphologically similar to the nearby graafian follicle. Immunohistochemistry showed positive labeling with antibodies to inhibin-alpha and cytokeratin in a pattern consistent with benign granulosa cells. CONCLUSION(S): Immunohistochemical stains for inhibin-alpha and cytokeratin are useful tools to help confirm granulosa cell origin, as demonstrated in this case involving an atypical histomorphologic picture of "embolization."

Enzyme-catalyzed ring-opening copolymerization of 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (MBC) with trimethylene carbonate (TMC): synthesis and characterization.

Enzymatic ring-opening copolymerization of 5-methyl-5-benzyloxycarbonyl-1,3-dioxan-2-one (MBC) with trimethylene carbonate (TMC) was investigated. A route to aliphatic polycarbonates decorated with pendent carboxylic acid groups is demonstrated. Lipase from Pseudomonas fluorescens (AK) was selected to perform the copolymerization at various monomers feed ratios. Copolymers with different composition were prepared by varying the monomer feed ratio from 10% to 80% MBC. 1H, 13C, and 1H-13C HETCOR NMR spectra were used to analyze the microstructure of the copolymers. The 1H NMR spectra indicated lower incorporation of TMC in the copolymer than was expected from the monomer feed ratio. Analysis of the 13C spectra did not indicate an ordered structure but instead suggested the formation of random polymers. This was further confirmed by the thermal data obtained for representative samples. The thermal properties at different feed ratios of poly[MBC-co-TMC] copolymers were investigated by differential scanning calorimetry (DSC). No melting temperature (Tm) for either homopolymers or copolymers was observed. A plot of 1/Tg(K) vs the weight composition of MBC in the copolymers was constructed and was consistent with copolymers that tend toward random distribution; this was confirmed from the NMR data.

Coleomegilla maculata (Coleoptera: Coccinellidae) predation on pea aphids promoted by proximity to dandelions.

The impact of a predator on its prey may depend on the presence of other species in the community. In particular, if predators are attracted to areas containing one prey species, another prey species may suffer greater predation if it occurs in the same areas. If the predator is omnivorous, this may occur even if one prey species is an animal and the other is a plant. We investigated the role of local dandelion densities on the impact of the predator Coleomegilla maculata on pea aphids in alfalfa fields. At small spatial scales, increased dandelion densities were associated with high C. maculata densities, presumably because these omnivorous ladybird beetles aggregated to pollen resources. In turn, the high C. maculata densities were associated with low aphid densities, presumably because of increased predation. We used laboratory cages to simulate C. maculata foraging in two adjacent patches of alfalfa, one with dandelions and one without. As in the field, the laboratory experiment showed that C. maculata aggregated to alfalfa interspersed with dandelions, which resulted in increased predation on aphids on alfalfa. This study demonstrates that a pollen-producing plant can indirectly decrease nearby herbivore densities by attracting an omnivorous predator.

Cancer-associated retinopathy in a patient with advanced epithelial ovarian carcinoma.

BACKGROUND: Paraneoplastic phenomena, such as retinopathy, may herald an unsuspected gynecologic malignancy. CASE: A 75-year-old woman presented to a neuro-ophthalmologist with abrupt onset of unilateral visual loss. A diagnosis of branch retinal artery occlusion was made and she was treated with aspirin. An echocardiogram subsequently revealed atrial dilation and she was placed on coumadin therapy. Her vision worsened and a cancer-associated retinopathy was entertained. A serum cancer-associated retinopathy antibody was detected; subsequent computed tomographies of the abdomen and pelvis revealed findings consistent with a primary ovarian carcinoma. CONCLUSION: Patients with unexplained ophthalmologic symptoms may harbor an underlying gynecologic cancer.

Prenatal ultrasound detection of isolated neural tube defects: is cytogenetic evaluation warranted?

OBJECTIVE: To determine the value of cytogenetic evaluation in fetuses with isolated neural tube defects diagnosed by prenatal ultrasound. METHODS: Fifty-five thousand two hundred sixty obstetric ultrasounds performed for various indications at the Indiana University Prenatal Diagnostic Center from July 1988 to March 1994 were reviewed using a computerized data base. Excluding all cases of anencephaly, fetuses with isolated neural tube defects were identified. Maternal demographic data, pregnancy outcomes, level of defect, and fetal karyotype when available were obtained. Statistical analysis was performed using the chi 2 test, when appropriate. P < or = .05 was considered statistically significant. RESULTS: Seventy-seven medical record charts of women with prenatally diagnosed isolated fetal neural tube defects were reviewed. Nineteen pregnancies were terminated, 42 pregnancies were delivered, and 16 pregnancies were lost to follow-up. Karyotypes were available in 43 of the 77 cases (55.8%). The theoretical risk of chromosomal anomalies in this sample population based solely on maternal age was 0.3%. Of the 43 documented karyotypes, seven chromosomal anomalies were discovered (16.3%). The difference was statistically significant (P = .012). Detected chromosomal anomalies included two trisomy 18, two triploid 69,XXX, one triploid 69,XXY, one balanced Robertsonian translocation t(13q,14q), and one inversion in the q arm of the X chromosome. CONCLUSION: The prevalence of karyotypic abnormalities is significantly increased in fetuses with isolated neural tube defects; therefore, prompt antenatal genetic evaluation should be considered in such cases.

Neural tube defects and omphalocele in trisomy 18.

A trisomy 18 fetus with severe congenital anomalies including craniorachischisis, large omphalocele, and bilateral cleft lip and palate is reported. The occurrence of neural tube defects and/or omphalocele in reported cases of trisomy 18 is discussed and the frequency of these anomalies in 85 trisomy 18 patients evaluated at Indiana University School of Medicine from 1963 to 1986 is reviewed. In this series of patients the frequency of neural tube defects was 7.0% and the frequency of omphaloceles was 5.9%. The percentage of these findings in our cases supports the premise that neural tube defects and omphaloceles are part of the trisomy 18 phenotype. Since fetuses with trisomy 18 are subject to early fetal loss or premature birth, the more subtle physical features of this condition may not be apparent. Thus, karyotyping of fetuses and premature infants with either neural tube defect or omphalocele should be considered.

Acephalus-acardia in twins with aneuploidy.

Since 1963, 11 cases have been reported in which both the acardiac twin and the "normal" co-twin were studied cytogenetically. Aneuploidy or polyploidy was clearly identified in the acardiac twin in 7 cases and in the co-twin in 1 case. We report on 2 additional twin pairs in which aneuploidy was associated with acephalus-acardia. In both cases the "normal" co-twin had a Klinefelter (47,XXY) karyotype. Chromosome analysis in the 2 acardiac twins documented a 47,XXY constitution in one and 94,XXXXYY anomaly in the other. One of the "normal" co-twins also had the VATER association. Given these data we would recommend chromosome analysis of both members of a twin pair when one has acephalus-acardia.