Effect of Aloe vera preparations on the human bioavailability of vitamins C and E

There are no literature references describing the effect of consumption of Aloe vera liquid preparations on the absorption of water- or fat-soluble vitamins. There is a very large population worldwide which consume vitamins and many people also consume Aloe. Thus we report the effect of Aloe on the human absorption of vitamins C and E, the most popular vitamin supplements. The plasma bioavailability of vitamins C and E were determined in normal fasting subjects, with eight subjects for vitamin C and ten subjects for vitamin E. In a random crossover design, the subjects consumed either 500 mg of ascorbic acid or 420 mg of vitamin E acetate alone (control), or combined with 2 oz of two different Aloe preparations (a whole leaf extract, or an inner fillet gel). Blood was collected periodically up to 24 h after consumption. Plasma was analyzed for ascorbate and tocopherol by HPLC with UV detection. There was no significant difference in the areas under the plasma ascorbate–time curves among the groups sincerely due to large differences within the groups. For comparative purposes the control area was 100%. The Aloe Gel area was 304%, and Aloe Whole Leaf 80%. Only Aloe Gel caused a significant increase in plasma ascorbate after 8 and 24 h. For vitamin E, the results for the relative areas were control 100%, Gel 369%, and Leaf (198%). Only the Aloes produced a significant increase in plasma tocopherol after 6 and 8 h. Both Aloes were significantly different from the control after 8 h. Aloe Gel was significantly different from the baseline after 24 h. The Aloes slowed down the absorption of both vitamins with maximum concentrations 2–4 h later than the control. There was no difference between the two types of Aloe. The results indicate that the Aloes improve the absorption of both vitamins C and E. The absorption is slower and the vitamins last longer in the plasma with the Aloes. Aloe is the only known supplement to increase the absorption of both of these vitamins and should be considered as a complement to them.     

High levels of genetic differentiation and selfing in the Brazilian cerrado fruit tree Dipteryx alata Vog. (Fabaceae)

Dipteryx alata is a native fruit tree species of the cerrado (Brazilian savanna) that has great economic potential because of its multiple uses. Knowledge of how the genetic variability of this species is organized within and among populations would be useful for genetic conservation and breeding programs. We used nine simple sequence repeat (SSR) primers developed for Dipteryx odorata to evaluate the genetic structure of three populations of D. alata located in central Brazil based on a leaf sample analysis from 101 adults. The outcrossing rate was evaluated using 300 open-pollinated offspring from 25 seed-trees. Pollen dispersal was measured by parentage analysis. We used spatial genetic structure (SGS) to test the minimal distance for harvesting seeds in conservation and breeding programs. Our data indicate that the populations studied had a high degree of genetic diversity and population structure, as suggested by the high level of divergence among populations . The estimated outcrossing rate suggested a mixed mating system, and the intrapopulation fixation index was influenced by SGS. We conclude that seed harvesting for genetic conservation and breeding programs requires a minimum distance between trees of 196 m to avoid collecting seeds from related seed-trees.     

Characterization of a cDNA encoding a putative chitinase from teratocytes of the endoparasitoid Toxoneuron nigriceps

Females of insect endoparasitoids inject substances along with the egg at oviposition, which can regulate or induce changes in a number of host physiological processes to benefit the developing parasitoid. These changes can be caused by substances such as venoms, calyx fluids, or symbiotic‐associated virus particles (polydnavirus), which are injected by females along with their eggs, and by substances secreted by parasitoid‐derived tissues (teratocytes) or the developing parasitoid larvae. Teratocytes (dissociated cells of the serosal membrane after parasitoid eclosion) release substances that have roles (i) in parasitoid nutrition, (ii) in the digestion of host tissues, and (iii) in the regulation of host development. Teratocytes of Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae) have been implicated in the arrestment of the host development and in the regulation of circulating levels of host ecdysteroids. Here we describe the cDNA of a teratocyte‐secreted chitinase and its expression during parasitoid development, and discuss its putative role in this host–parasitoid association.     

Substrate selectivity of squalene synthetase.

Six 1-3H-labeled analogues of farnesyl pyrophosphate have been studied as potential substrates for yeast and rat liver squalene synthetases: 2-methylfarnesyl pyrophosphate (4), 3-demethylfarnesyl pyrophosphate (5), 7,11-dimethyl-3-ethyl-2,6,10-dodecatrienyl pyrophosphate (6), 6,7,10,11-tetrahydrofarnesyl pyrophosphate (7), 4-methylthiofarnesyl pyrophosphate (8), and 4-fluorofarnesyl pyrophosphate (9). Analogues 4 and 5 are enzymatically incorporated into 11-methylsqualene (10) and 10-demethylsqualene (11), respectively, even if no farnesyl pyrophosphate is added to the incubations. None of the other analogues gives nonpolar products with either the yeast or liver enzymes. No tritium is enzymatically released to the medium from any of the analogues, indicating that they are not accepted at the first (proton exchanging) site. The data rule out formation of dead-end presqualene pyrophosphate products with analogues as first, but not as second, substrates. Implications of these results for the enzyme active-site topology and mechanism are discussed.     

The development and application of a radioimmunoassay for 18-hydroxy-corticosterone.

A sensitive and specific radioimmunoassay has been developed for 18-hydroxy-corticosterone (18-OH-B) and applied to the measurement of this steroid in peripheral plasma. High specific activity label (3H-18-OH-B) was prepared using the incubation of 3H-corticosterone with duck adrenal mitochondria. Antisera were produced by immunisation with 18-OH-B gamma-lactone 3-oxime conjugated to bovine serum albumin. The antibodies examined showed 100% cross-reactivity with 18-hydroxy-deoxycorticosterone gamma-lactone (18-OH-DOC gamma-lactone), but minimal cross-reactivity with other steroids. Paper chromatography was used to separate 18-OH-DOC gamma-lactone from 18-OH-B gamma-lactone. The interassay precision was 7.6% and the intra-assay precision 11.0%. The accuracy of the method was confirmed by showing a linear relationship between amounts of 18-OH-B added and amounts of 18-OH-B gamma-lactone measured (y = 0.854 X +15.1, r = 0.9. p less than 0.001). The mean plasma level in normal subjects on an ad libitum sodium intake was 225 +/- 92.7 (SD) pg/ml (n = 17) when standing, and 99 +/- 38.3 (SD) pg/ml (n = 6) after lying down for 30 minutes.     

Nuclear secretory particles associated with the calyx cells of the ichneumonid parasitoid Campoletis sonorensis (Cameron)

Summary The present study is an ultrastructural investigation of the calyx region of the ichneumonid endoparasitoid Campoletis sonorensis. It appears that synthesis of electrondense secretory particles occurs within nuclei of calyx cells. The particles consist of an ovocylindrical electron-dense inner core and a surrounding unit membrane. After their formation the particles pass from the nucleus by budding through both membranes of the nuclear envelope. The particles, along with fully developed parasitoid eggs concentrate within the lateral oviduct lumen. Feulgen histochemical studies suggest the presence of DNA within the calyx fluid. The possible function of the particles is discussed.Approved for publication as TA 11744 by the Director, Texas Agricultural Experiment Station. Conducted in cooperation with the USDA and supported in part by Cotton, Inc. Grant CI—199 with funds made available through the USDA. Appreciation is also expressed to Sigma Xi for its contribution of funds during this study.     

Isolation, identification and synthesis of host-seeking stimulants for Cardiochiles nigriceps, a parasitoid of tobacco budworm

Several methyl-branched saturated C₃₂, C₃₃, and C₃₄ hydrocarbons have been identified from larvae and mandibular glands of Heliothis virescens (F.) (Lepidoptera, Noctuidae) that trigger a short-range host-seeking response of its parasitoid, Cardiochiles nigriceps, Viereck (Hymenoptera: Branconidae). Although the individual components elicited a response, a mixture of the most active C₃₂, C₃₃, and C₃₄ hydrocarbons was significantly more active than the individual components; some mixtures were as active as the contents of the mandibular gland of the host.

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Zusammenfassung Isomere Monomethylalkane in den Larven und in der Mandibeldrüse von Heliothis virescens, die bei ihrem Parasitoid, Cardiochiles nigriceps, nach Kontakt eine wirtsuchende Wirkung besitzen, wurden identifiziert. Mischungen mehrerer, als aktiv erkannter Substanzen (z.B. 12-Methyl C₃₁+12-Methyl C₃₂+13-Methyl C₃₃, optimal zusammen 500 ng) wirkten stärker als die einzelnen Komponenten und konnten die Wirkung des Mandibulardrüseninhalts erreichen.