A strategy to provide long‐term control of weedy rice while mitigating herbicide resistance transgene flow,and its potential use for other crops with related weeds

Transgenic herbicide‐resistant rice is needed to control weeds that have evolved herbicide resistance, as well as for the weedy (feral, red) rice problem, which has been exacerbated by shifting to direct seeding throughout the world—firstly in Europe and the Americas, and now in Asia, as well as in parts of Africa. Transplanting had been the major method of weedy rice control. Experience with imidazolinone‐resistant rice shows that gene flow to weedy rice is rapid, negating the utility of the technology. Transgenic technologies are available that can contain herbicide resistance within the crop (cleistogamy, male sterility, targeting to chloroplast genome, etc.), but such technologies are leaky. Mitigation technologies tandemly couple (genetically link) the gene of choice (herbicide resistance) with mitigation genes that are neutral or good for the crop, but render hybrids with weedy rice and their offspring unfit to compete. Mitigation genes confer traits such as non‐shattering, dwarfism, no secondary dormancy and herbicide sensitivity. It is proposed to use glyphosate and glufosinate resistances separately as genes of choice, and glufosinate, glyphosate and bentazone susceptibilities as mitigating genes, with a six‐season rotation where each stage kills transgenic crop volunteers and transgenic crop × weed hybrids from the previous season. Copyright © 2009 Society of Chemical Industry     

Novel edible coating based on aloe vera gel to maintain table grape quality and safety

A novel edible coating based on Aloe vera gel obtained according to SP Patent Filed 200302937 has been used as a means of preservation to maintain the quality and safety of cv. Crimson Seedless table grapes during cold storage and subsequent shelf life. Table grapes have a crucial economic value as a dessert fruit, but once harvested show a reduction of shelf life due to a rapid loss of quality. Uncoated clusters showed a rapid deterioration with an estimated shelf life period of 7 days at 1 degrees C plus 4 days at 20 degrees C, based on the fast weight loss, color changes, accelerated softening and ripening, rachis browning, and high incidence of berry decay. On the contrary, those clusters treated with A. vera gel significantly delayed the above parameters related to postharvest quality losses, and storability could be extended up to 35 days at 1 degrees C. Interestingly, this edible coating was able to reduce the initial microbial counts for both mesophillic aerobic and yeast and molds, which significantly increased in uncoated berries over storage. Moreover, the sensory analyses revealed beneficial effects in terms of delaying rachis browning and dehydration and maintenance of the visual aspect of the berry without any detrimental effect on taste, aroma, or flavors. To the authors' knowledge, this is the first time A. vera gel has been used as an edible coating in fruits, which would be an innovative and interesting means for commercial application and an alternative to the use of postharvest chemical treatments.     

Antioxidant and Antihypertensive Potential of Protein Fractions from Flour and Milk Substitutes from Canary Seeds (<Emphasis Type="Italic">Phalaris canariensis</Emphasis> L.)

Canary seed (Phalaris canariensis) is used to feed birds but it has been recently considered a promising cereal with nutraceutical potential for humans. The aim of this work was to analyze the protein fractions from canary seed flour and from milk substitutes (prepared by soaking the seeds in water 12 and 24 h), and to evaluate antioxidant and antihypertensive capacity of peptides obtained after in vitro digestion. Prolamins were the major protein fraction, followed by glutelins. After digestion, albumins and prolamins fractions from milks presented higher levels of peptides than flour, globulins showed more peptides in flour and glutelins were found in similar concentrations in all samples; 24 h milk prolamins had the highest concentration of peptides. Purification by high performance liquid chromatography (HPLC), sequencing of peptides, in vitro antioxidant ABTS (2,2′-azino-bis, 3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, and antihypertensive capacity (angiotensin converting enzyme (ACE) assay), indicated that peptides from canary seed prolamins were the most efficient compounds with antioxidant and antihypertensive activity. Canary seeds may be considered an accessible and cheap source to prepare milk substitutes with high contents of bioactive peptides with remarkable functional properties to promote better human health and healthy ageing.     

Chemical Composition and Ruminal Degradability of Spineless Cactus Grown in Northeastern Brazil

A study was conducted to determine chemical composition and ruminal nutrient degradability of eight spineless cactus cultivars grown in northeastern Brazil. Results showed that neutral detergent fiber was similar for all cultivars and averaged 249 g · kg^-1 ± 7.3 SEM. Acid detergent fiber ranged between 148 g · kg^-1 and 207 g · kg^-1 with some significant differences between cultivars. Starch and water-soluble carbohydrates were similar for all cultivars and averaged 198 g · kg^-1 ± 6.3 SEM and 155 g · kg^-1 ± 9.0 SEM, respectively. Protein content was less than 50 g · kg^-1 with some significant differences between cultivars. Calcium was the mineral with the highest concentration followed by potassium and magnesium with no differences between cultivars. Effective ruminal degradability of dry matter and neutral detergent fiber were unaffected by cultivar and averaged 701 g · kg^-1 ± 8.4 SEM and 503 g · kg^-1 ± 5.8 SEM, respectively. It was concluded that cultivars had little impact on chemical composition and ruminal degradability of spineless cactus. Based on chemical composition and in situ ruminal degradability, spineless cactus can be considered an excellent source of fermentable carbohydrates for grazing and nongrazing ruminants. Because of its high carbohydrate quality, spineless cactus can be used an emergency feed or as part of a complete diet providing that the diet contains an adequate amount of degradable protein.     

Photoreceptor regulation of CONSTANS protein in photoperiodic flowering

Many plants flower in response to seasonal fluctuations in day length. The CONSTANS (CO) gene of Arabidopsis promotes flowering in long days. Flowering is induced when CO messenger RNA expression coincides with the exposure of plants to light. However, how this promotes CO activity is unknown. We show that light stabilizes nuclear CO protein in the evening, whereas in the morning or in darkness the protein is degraded by the proteasome. Photoreceptors regulate CO stability and act antagonistically to generate daily rhythms in CO abundance. This layer of regulation refines the circadian rhythm in CO messenger RNA and is central to the mechanism by which day length controls flowering.     

Histomorphometric changes of the fore-stomach of lambs fed with diets containing spineless cactus genotypes resistant to Dactylopius sp.

Tropical Animal Health and Production - The histomorphometric parameters of the fore-stomach epithelium of lambs fed with spineless cactus genotypes resistant to Dactylopius sp. were evaluated....     

Phytopythium chamaehyphon causing corm and root rot of uncultivated taro (Colocasia esculenta)

European Journal of Plant Pathology - Taro (Colocasia esculenta) is a food crop cultivated in tropical areas of the world. However, when uncultivated, taro is considered an invasive plant species...     

Validation of the MAC technique in dogs and rabbits

Minimum alveolar concentrations (MAC) are determined using one of the different noxious stimuli (clamping, electrical stimulation, or surgical incision), based on a study conducted in the 1960s with three dogs. This study compares different noxious stimuli applied in a randomized order in dogs (n = 10) anesthetized with isoflurane (I) and halothane (H), and in rabbits (n = 10) anesthetized with I. Anesthesia was induced with the anesthetic in oxygen and maintained with mechanical ventilation. End‐tidal anesthetic (Fe ′A) and CO₂ (Pe ′CO₂) concentrations were monitored with a calibrated infrared gas analyzer. Pe ′CO₂ and body temperature were maintained within normal limits. Noxious stimuli included skin incision on the lateral chest (SI), clamping of the tail (TC), fore‐ (FC) and hindlimb paw (HC), and electrical current (50 V at 50 cycles second for 10 msecond pulses) applied to the fore‐ (FE) and hindlimb (HE), and oral mucosa (OE) (except rabbits). SI was applied first and only for the first two consecutive measurements using the up–down method for sequential sampling of quantal‐response data. After an initial equilibration period of at least 20 minutes at an Fe ′A of 1.4% (H) or 1.7% (I), the Fe ′A was decreased in the first animal to 0.85% of H (dog) or 1% of I (dog and rabbit) and maintained for at least 20 minutes before the noxious stimuli. If the animal responded or did not respond, the stimuli were then tested at an Fe ′A 0.1% higher or lower, respectively. The new Fe ′A was kept constant for at least 20 minutes and the noxious stimuli repeated until purposeful movement ceased or returned, respectively. MAC was defined as the Fe ′A mid‐way between the value permitting and preventing purposeful movement. Data were analyzed using an anova . MAC for I in dogs was 1.27 ± 0.047 (mean ± SEM) for TC, FC, and HC; 1.36 ± 0.035 for OE; 1.35 ± 0.040 for FE and HE; and 0.99 for SI. MAC for H in dogs was 0.97 ± 0.028 for TC; 0.96 ± 0.032 for FC and HC; 1.04 ± 0.033 for OE, FE, and HE; and 0.73 for SI. MAC for I in rabbits was 2.08 ± 0.021 for TC, FC, and HC; 2.04 ± 0.023 for FE and HE; and 0.90 for SI. MAC for SI was significantly lower than the other methods. In conclusion, electrical current and clamping resulted in similar MAC values.     

Oxygen Consumption Response to Gradual Hypoxia in Spider Crab,Maja brachydactyla: Critical and Lethal Oxygen Saturations and Recovery Ability

Spider crab, Maja brachydactyla, is a crustacean with interesting biological characteristics for intensive aquaculture. However, physiological studies are needed to establish the optimal conditions for its culture and maintenance. We analyzed the oxygen consumption response of spider crab to gradual hypoxia in relation to animal weight (W: 0.42–1.62 kg) and water temperature (T: 17.8–26.3 C), along with its ability to recover. Spider crab behaved as an oxygen regulator, maintaining its oxygen consumption constant until it reached critical oxygen saturation. This value varied between 24.1 and 53.3% oxygen saturation (42.4 ± 7.4% Sat.; 2.95 ± 0.43 mgO₂/L), and significantly depended on the temperature (P < 0.01). The lethal oxygen saturation varied from 6.8 to 19.3% Sat. (12.57 ± 4.25% Sat.; 0.88 ± 0.29 mgO₂/L) depending on temperature and body weight (P < 0.05). When oxygen levels were re‐established after exposure to acute hypoxia, the animals recovered, oxygen consumption remaining above the routine value for up to 15–20 h. We suggest survival oxygen saturation levels for spider crab of between 100 and 65% in the experimental conditions of this study.     

Spatiotemporal dynamics of bacterial wilt in Eucalyptus

Bacterial wilt (caused by Ralstonia spp.) is one of the most damaging diseases of Eucalyptus species, and is responsible for substantial losses to producers. For efficient, scientifically-based management of this disease, it is necessary to understand the various factors involved in its development, including greater knowledge of the epidemiology of the pathogen on Eucalyptus spp. This study aimed to determine the spatialtemporal dynamics of bacterial wilt in Eucalyptus under natural infection conditions. An experiment was conducted in a commercial plantation in the municipality of Itinga, state of Maranhão, Brazil, using the clone FGCA0385 (Eucalyptus urophylla var. platyphylla). The study comprised of four plots composed of 450 plants each, subdivided into nine rows with 50 plants per row with a spacing of 3 × 3 m. Disease incidence was quantified over 1 year. The spatial dynamics of the disease was determined using the dispersion index, a modified Taylor law, and the analysis of the dynamics and structure of foci. For temporal dynamics, the curve of the disease incidence progress was plotted, and the data were analysed by simple linear regression analysis fitted to three empirical models: logistic, monomolecular, and Gompertz. The distribution pattern of Eucalyptus bacterial wilt was random, as confirmed by the Index of dispersion. Analysis of the dynamics and structure of the foci, showed that 69 disease foci occurred, 44 of which were unitary, with an average number of plants per focus of 1.63. Foci had greater length in the direction of the planting line. The epidemics were best described by the monomolecular model, with an estimated incidence of Eucalyptus bacterial wilt of 27.77% in the fourth year of the study. According to the spatiotemporal dynamics of this work, management strategies such as eliminating symptomatic plants and crop renovation can be used based on economic viability.