Peeled Oat Research Articles

Life history of Trogoderma granarium Everts (Coleoptera: Dermestidae) on peeled barley, peeled oats and triticale

The life history of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), was investigated on cracked peeled barley, cracked peeled oats and cracked triticale. The results suggest that the biological and demographic parameters of T. granarium are affected by the tested commodities. The developmental time of total immature period of T. granarium was significantly lower on barley (35.06 days) than on oats (42.87 days) and triticale (43.58 days). Mean longevities of adult females were 7.00, 7.89 and 8.24 days, and for adult males were 5.79, 6.05 and 5.49 days when T. granarium fed on barley, oats and triticale, respectively. The highest fecundity recorded when T. granarium fed on barley (39.0 eggs/female) or triticale (35.2 eggs/female), but it was significantly lower when this species fed on oats (25.4 eggs/female). While the net reproductive rate did not differ significantly when T. granarium fed on barley (14.6 females/female), oats 10.2 (females/female) and triticale (11.0 females/female), the mean generation time was significantly lower when fed on barley (40.5 days) than on oats (48.7 days) and triticale (46.1 days). The intrinsic rate of increase of T. granarium did not differ significantly when fed on barley and triticale (0.066 and 0.052 females/female/day, respectively), but it was significantly lower when fed on oats (0.047 females/female/day). The biological and demographic parameters of T. granarium may be incorporated in population models that evaluate the population dynamics aiming to the optimization of management strategies against this noxious species.

Influence of commodity on the population growth of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae)

In this study, we compared different amylaceous commodities for their suitability for population growth of the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), which is an important pest of stored maize in the tropics. In this context, we conducted three different series of tests. In the first test, we compared whole grains: whole barley, peeled barley, maize, whole oats, peeled oats, peeled rice, rough rice, rye, triticale, and wheat. Only maize was found suitable for P. trunctatus to reproduce and significantly increase its population, but there were certain commodities where surviving adults were found. In the second series of tests, we evaluated the percentage of cracked maize kernels on P. truncatus population growth. In this test, we found that the numbers of alive P. truncatus adults in the vials that contained 100% cracked kernels was higher than these with lower percentages of cracked kernels (5–50%) or no cracked kernels (0%). Finally, in the third series of tests, we compared eleven different types of amylaceous commodities with maize. These commodities were: whole maize (whole kernels), whole oat flakes, maize flour, whole barley flour, pasta, white soft wheat flour, whole soft wheat flour, white hard wheat flour, whole hard wheat flour, whole rye flour, and semolina. The results indicated that only whole maize and maize flour were suitable for P. truncatus population growth. Nevertheless, in some of the other commodities tested, there was a low number of adults and immatures that were able to survive 60 days after the incorporation of the parental adults. The results of the present study indicate that from the commodity range tested here, only maize was suitable for P. truncatus population growth. Nevertheless, the marginal numbers of surviving individuals in the non-maize commodities and the role of these substrates as potential “non-preferred food vehicles” that may contribute to further spread of this species should be tested in more detail.

Population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on different commodities

We evaluated the population growth of the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on different grains, cracked wheat containment categories and amylaceous materials by conducting three series of laboratory bioassays. In the first series, peeled barley, whole (raw) barley, peeled oats, whole (raw) oats, peeled rice, rough rice, rye, triticale and hard wheat were tested. In the second series, six cracked wheat containment categories were tested: wheat containing intact kernels only (0% cracked kernels), wheat containing 5% cracked kernels and 95% intact kernels, wheat containing 10% cracked kernels and 90% intact kernels, wheat containing 25% cracked kernels and 75% intact kernels, wheat containing 50% cracked kernels and 50% intact kernels and wheat containing 100% cracked kernels. In the third series, the following amylaceous commodities were tested: hard wheat (intact kernels), whole oat flakes, maize flour, whole barley flour, pasta, white soft wheat flour, whole soft wheat flour, white hard wheat flour, whole hard wheat flour, whole rye flour and semolina. Significantly more dead adults were found on wheat than on peeled barley, maize, whole oats, rough rice and rye. Significantly more larvae alive were found on wheat and triticale, than on the other grains, with the exception of oats, both whole and peeled. The increase of the percentage of cracked wheat kernels increased population growth, except in the case of 10% cracked wheat kernels. In vials that contained 100% cracked wheat kernels, 584.1 individuals per vial were found, which was 3.7 times more than the respective number of larvae alive in vials with intact wheat kernels only. Significantly more dead adults were found on whole barley flour than on the other commodities. More than 1213 larvae per vial were recorded on whole barley flour, which was 1.3–15 times higher than the other commodities. The lowest number of larvae alive was found on pasta, followed by the white soft wheat flour. The findings of the present work show that some commodities are more prone to spread T. granarium than others, a fact which should be seriously taken into account in international trade of grains and related amylaceous products.

INCLUSÃO DE DIFERENTES FONTES DE AMIDO NA DIETA DE JUNDIÁS (Rhamdia quelen): PARÂMETROS METABÓLICOS E BIOQUÍMICOS

This study was conducted to evaluate the influence of ingestion of different sources of starch on enzymatic and metabolic indicators in blood and liver of Rhamdia quelen. The experiment was conducted during 20 days in water recirculation system. Sixty fishes (initial average weight 60g) were used and divided into three treatments composed of the following diets: inclusion of peeled oats, defatted rice bran and control diet, all with 36% crude protein and 3,200 Kcal DE/Kg. There was no significant difference in growth parameters. The analysis demonstrated a reduction in liver glycogen content for the treatment with oats; however, no apparent changes in the activity of the enzymes alanine-aminotransferase and glucose-6-phosphatase were observed, raising the possibility that the fishes did not use gluconeogenesis. The blood analysis, showed no significant differences in the determinations of total cholesterol, HDL cholesterol and albumin; however, serum levels of total protein were higher for treatment with defatted rice bran, and triglyceride levels were lower in animals that received diet containing oat as starch source. It can be concluded that Rhamdia quelen is able to metabolize various sources of carbohydrate, without the need to use either diet or body protein as an energy source.KEYWORDS: carbohydrate; fish nutrition; intermediary metabolism.

Insecticidal Effect of NeemAzal Against Three Stored-Product Beetle Species on Rye and Oats

The insecticidal effect of the azadirachtin-based insecticide, NeemAzal, was examined against adults of Rhyzopertha dominica (F.), Sitophilus oryzae (L.), and Tribolium confusum Jacquelin du Val in rye, whole oats, and peeled oats. The insecticide was applied at three dose rates, which were equivalent to 50, 100, and 200 ppm of azadirachtin A. Adults of the above-mentioned species were exposed to the treated grains at 25 degrees C and 65% RH, and mortality was assessed after 24 h, 48 h, 7 d, and 14 d of exposure. Then, all adults were removed, and the treated substrate remained at the same conditions for an additional 45 d. After this interval, the grains were checked for progeny production. In all species and commodities tested, mortality increased with the increase of dose and exposure interval, except for T. confusum on whole and peeled oats. For R. dominica, NeemAzal was more effective on oats than on rye and peeled oats. In contrast, at rates > or = 100 ppm, azadirachtin was equally effective against S. oryzae on whole rye and oats, where mortality was 100% after 7 and 14 d of exposure, respectively. NeemAzal was not very effective against T. confusum where adult mortality was low, even after 14 d of exposure at the highest rate. For all species, significantly less progeny were recorded in the treated grains than in the untreated grains, with the exception of T. confusum on oats where offspring was significantly reduced only at the highest rate.

Osmoregulation by Oat Coleoptile Protoplasts (Effect of Auxin).

The effect of auxin on the physiology of protoplasts from growing oat (Avena sativa L.) coleoptiles was investigated. Protoplasts, isolated iso-osmotically from peeled oat coleoptile segments, were found to swell steadily over many hours. Incubated in 1 mM CaCl2, 10 mM KCl, 10 mM 2-(morpholino)ethanesulfonic acid/1,3-bis-[tris(hydroxymethyl)methylamino]propane, pH 6.5, and mannitol to 300 milliosmolal, protoplasts swelled 28.9% [plus or minus] 2.0 (standard error) after 6 h. Addition of 10 [mu]M indoleacetic acid (IAA) increased swelling to 41.1% [plus or minus] 2.1 (standard error) after 6 h. Swelling (in the absence of IAA) was partially dependent on K+ in the bath medium, whereas auxin-induced swelling was entirely dependent on K+. Replacement of mannitol in the bath by Glc increased swelling (in the absence of IAA) and eliminated auxin-induced swelling. Swelling with or without IAA was inhibited by osmotic shock and was completely reversed by 0.1 mM NaN3. Sodium orthovanadate, applied at 0.5 mM, only gradually inhibited swelling under various conditions but was most effective with protoplasts prepared from tissue preincubated in vanadate. Our data are interpreted to suggest that IAA increases the conductance of the plasma membrane to K+.

Contamination of oat mesophyll protoplasts by apoplastic polyamine oxidase

Mesophyll protoplasts isolated from peeled oat (Avena sativa L. cv Victory) leaves with 1% (w/v) Cellulysin in 20 mM KPO4, pH 5.5 and 0.6 M sorbitol retain about 6% of the polyamine oxidase (PAO, EC 1.4.3.4) activity of the whole peeled leaf. However, more than 99% of the oat leaf PAO activity is apoplastic and can be extracted by vacuum infiltration with 200 mM NaCl and this procedure extracts no activity for the cytoplasmic marker enzyme glucose‐6‐phosphate dehydrogenase (G6PD, EC 1.1.1.49). By these criteria we consider PAO in oat leaves to be totally apoplastic and PAO found in the isolated protoplast to be contamination. The degree of protoplast contamination by PAO depends on the pH and ionic strength of the isolating and washing medium. It can be eliminated by washing protoplasts in 0.6 M sorbitol with 100 mM KPO4, pH 6.5. Pellets of lysed protoplasts incubated with dialyzed apoplastic enzymes in 5 mM KPO4, pH 5.5 adsorb about 87% of the added PAO activity but only about 25% of the added peroxidase (EC 1.11.1.7) activity. The adsorbed activity can be solubilized from the pellet by extraction with 1 M NaCl. The results demonstrate that weakly ionically bound cell wall enzymes may contaminate protoplasts isolated and purified by conventional techniques.

The Spread of Food Producing Techniques in a Captive Flock of Jackdaws

The spread of techniques to get peeled oats from a food dispenser was observed in a captive flock of 28 jackdaws (Corvus monedula) in two replicates. It was hypothesized that the quality of the social relationship between two jackdaws could affect the probability of social learning within that dyad. Therefore technique acquisition of socially bonded dyads (pairs) and socially indifferent dyads (non-pairs) was compared. The results can not falsify the hypothesis of individual learning regardless of the partner's knowledge about a successful technique. Pair members did not learn faster from each other than members of non-pair dyads. Pair members did not preferentially acquire the same technique. There was no indication that the rate of technique acquisition within the flock increased with the number of established technicians. Qualitative observations support the explanation of individual trial-and-error learning.

Phytotoxic effects of cadmium in leaf segments ofAvena sativa L., and the protective role of calcium

It is shown that ethylene production can be stimulated in peeled oat leaf segments in the dark by cadmiun at concentrations below 0.01 mM, and that cadmium-stimulated stress ethylene accelerates senescence processes. Higher cadmium concentrations cause membrane deterioration and inhibit ethylene production and senescence. These effects of cadmium are antagonized by calcium. This indicates a possible protection of plant cell against cadmium toxicity by calcium.

Putrescine and Acid Stress

Incubation of peeled oat Avena sativa L. var Victory leaf segments on media of pH 5.0 or below leads to a rapid and massive increase in the titer of putrescine while incubation at pH values above 5.0 causes little or no change. The low pH effect is independent of the buffer system employed. Putrescine levels rise within 3 hours and reach their peak 8 to 9 hours after acidification. At this time, putrescine titer is eight times greater at pH 3.5 than at 6.0. None of the other polyamines shows a response to changes in external pH. The increase in putrescine is blocked by the addition of cycloheximide or dl-alpha-difluoromethylarginine, a specific inhibitor of the putrescine biosynthetic enzyme, arginine decarboxylase. In one experiment, arginine decarboxylase activity was 110% greater at pH 4.0 than at 6.0 after a 4-hour incubation, although the average increase over many experiments was 47%. The activity of the other possible putrescine biosynthetic enzyme, ornithine decarboxylase, falls throughout the incubation period and is virtually equal at pH 4.0 and 6.0.

Regulation of H+ Excretion

When the protoplasts of peeled oat leaf segments (Avena sativa L.) expand after a brief plasmolysis (osmotic shock), fusicoccin-enhanced H(+) excretion is reduced and protein is released to the rehydration medium. This shock protein seems to arise from the cell surface, not from the interior of leaky cells or from broken cells, because (a) the protein differs quantitatively and qualitatively from protein of cell homogenates as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; (b) peroxidase, phosphatase, and malate dehydrogenase activities, which are associated with the cell surface, are detected in the shock fluids; (c) the specific activities of enzymes in shock fluids are different than those of cell homogenates; (d) the amount of protein released is correlated with tissue mass, not number of cut surfaces and is not diminished by pre-washing the tissue.Some of the shock protein may arise from plasmodesmata; this suggestion is based on (a) the cell surface origin of the protein; (b) the presence in the shock fluid of NADPH-cytochrome c reductase activity, usually associated with the endoplasmic reticulum which traverses plasmodesmata; (c) on the release of smaller amounts of protein after plasmolysis with polyethylene glycol 4000, an osmoticum which may tend to preserve plasmodesmata.The amount of protein released by osmotic shock is correlated with the extent of inhibition of fusicoccin-enhanced H(+) excretion. A specific function for the shock protein is implied by the presence of a component which specifically binds fusicoccin.

Effect of cycloheximide and kinetin on yield, integrity and metabolic activity of oat leaf protoplasts

The yield of protoplasts from cellulase-treated peeled oat leaf segments is increased if the leaves have previously been floated on cycloheximide (CH), rather than on water. The optimal CH level is 0.5 to 1.0 μg/ml. No effects are produced by pre-incubation times less than 6 h, and the optimal pretreatment time is about 18 h. Protoplasts from CH-pretreated leaves are more resistant to spontaneous lysis, and are more active in incorporating labeled l-leucine, uridine and thymidine into trichloroacetic acid (TCA)-insoluble materials than are protoplasts from leaves floated on water. Kinetin (Kn) acts like CH in almost all respects.