Detection of molecular markers linked to the durable adult plant stripe rust resistance gene Yr18 in bread wheat (Triticum aestivum L.)

Stripe rust of wheat caused by Puccinia striiformis West. f. sp. tritici presents a serious problem for wheat production worldwide, and identification and deployment of resistance sources to it are key objectives for many wheat breeders. Here we report the detection of simple sequence repeat (SSR) markers linked to the durable adult plant resistance of cv. ‘Otane’, which has conferred this resistance since its release in New Zealand in 1984. A double haploid population from a cross between ‘Otane’ and the susceptible cv. Tiritea’ was visually assessed for adult plant infection types (IT) in the glasshouse and field, and for final disease severity in the field against stripe rust pathotype 106E139A⁺. At least three resistance loci controlled adult plant resistance to stripe rust in this population. Quantitative trait loci (QTL) mapping results revealed that two of these, one on chromosome 7DS corresponds to the durable adult plant resistance gene Yr18 and other on chromosome 5DL were contributed from ‘Otane’; while the remaining one on chromosome 7BL, was contributed from the susceptible ‘Tiritea’. Interval mapping placed the ‘Otane’‐resistant segment near the centromere of chromosome 7DS at a distance of 7 cM from the SSR marker gwm44. The stability of QTL in the two environments is discussed. SSR gwm44 is potentially a candidate marker for identifying the durable resistance gene Yr18 in breeding programmes.     

Breeding oats for high yield and for resistance to crown rust in India

Summary The progenies of the crosses Landhafer × Punjab local, ag 331 × Punjab local and Gopher × Curt were studied in relation to their resistance against the most virulent race 227 of crown rust and their yield performance. Landhafer was found to possess one dominant gene for resistance to this race, while the oat cultivar ag 331 had two, Gopher had only one gene for resistance, the expression of which was suppressed by an inherent inhibitory factor. The few selected fixed lines of these crosses were put into multilocational yield trials. All the lines (cultures) of cross ag 331 × Punjab local were resistant to rust. They were superior to Kent by 4–46% in fodder and 2–35% in grain yield. The cultures of the cross Gopher × Curt were superior by 23–49% in fodder and by 9–35% in grain yield to Kent besides being resistant to rust.     

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC₉₀ of cinnamaldehyde against different Candida isolates ranged 100–500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H⁺-ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.     

Promising genetic resources for resistance to wheat streak mosaic virus and the wheat curl mite in wheat-<Emphasis Type="Italic">Thinopyrum</Emphasis> partial amphiploids and their derivatives

Wheat streak mosaic virus (WSMV), vectored by the wheat curl mite (WCM),Aceria tosichella Keifer, is one of the most destructive viral diseases of wheat found in many wheat producing areas of the world. Host resistance is the most effective method for controlling this disease and its vector. Symptomatological analysis and enzyme-linked immunosorbent assay (ELISA) were used to characterize WSMV-resistance in wheat-alien partial amphiploid lines and their derivatives. The results showed that most of partial amphiploids derived fromThinopyrum ponticum andTh. intermedium were free of systemic symptoms with very low ELISA readings that were similar to that of the non-inoculated Chinese Spring control. While the partial amphiploid lines 693 and PWM706 were identified as new genetic resources of resistance to WSMV. The present study demonstrated that both symptomatological and ELISA methods efficiently assessed WSMV-resistance in the wheat-alien hybrids and systemic symptom incidence and ELISA absorbance readings were highly correlated (r ₂ = 0.8658–0.9323) over time following inoculation. The ELISA results also indicated that the virus did not buildup in the plant tissues of these virus-resistant partial amphiploids. Similar results were observed in chromosome translocation and substitution lines that have the geneWsm1 conferring WSMV resistance. However, the lines containing the geneWsm1 and all the partial amphiploid lines, except Agrotana, were susceptible to the WCM. One line derived from a cross of wheat and Agrotana, was effective in controlling the spread of WSMV and was highly resistant to the WCM. Another line and an accession ofTriticum dicoccoides (Koern.) Schweinf. were highly susceptible to WSMV and WCM. Early disease development was delayed in a new hard red winter cultivar McClintock. The partial WSMV-resistance of McClintock was demonstrated by initially low ELISA readings, and a lower percentage of infected plants than other WSMV-susceptible wheat. The use of the identified promising sources of resistance to WSMV and the WCM in wheat breeding is discussed.LRC Contribution No. 387-01061.     

DNA topoisomerase I--targeted chemotherapy of human colon cancer in xenografts

Drug development is needed to improve chemotherapy of patients with locally advanced or metastatic colon carcinoma, who otherwise have an unfavorable prognosis. DNA topoisomerase I, a nuclear enzyme important for solving topological problems arising during DNA replication and for other cellular functions, has been identified as a principal target of a plant alkaloid 20(S)-camptothecin. Significantly increased concentrations of this enzyme, compared to that in normal colonic mucosa, were found in advanced stages of human colon adenocarcinoma and in xenografts of colon cancer carried by immunodeficient mice. Several synthetic analogs of camptothecin, selected by tests with the purified enzyme and tissue-culture screens, were evaluated in the xenograft model. Unlike other anticancer drugs tested, 20(RS)-9-amino-camptothecin (9-AC) induced disease-free remissions. The overall drug toxicity was low and allowed for repeated courses of treatment.     

A dog model to study ovary, ovarian ligament and visceral pain

Objective A dog model was developed to study visceral pain by stimulating the ovarian ligament. Study design Prospective experimental trial. Animals Twelve 1‐year old female hound dogs weighing 25.7 ± 3.6 kg. Methods Dogs were anesthetized with sevoflurane. The right ovary was accessed via laparoscopy. A suture was placed around the ovarian ligament and exteriorized through the abdominal wall for stimulation. The noxious stimulus consisted of pulling the ovary and ovarian ligament with a force transducer. The response to noxious stimulation was determined using the anesthetic minimum alveolar concentration requirement (MAC) for sevoflurane. The ovarian MAC was compared to the standardized somatic noxious stimulation tail clamp MAC. The results are depicted as mean ± SD and corrected to sea‐level. Results The stimulus–response curve during ovarian stimulation in three dogs was hyperbolic and best represented by a three‐parameter logistic growth curve model. The curve plateaued at 7.12 ± 4.19 N. From the stimulus‐response curve, we chose 6.61 N to test the consistency and repeatability of the model in nine dogs. The ovarian stimulation MAC for sevoflurane in these dogs was 2.16 ± 0.46%. The ovarian stimulation confidence interval and limits are comparable to the results from tail stimulation MAC. The tail stimulation MACs before and after laparoscopy surgery were not different (1.86 ± 0.28% and 1.77 ± 0.38% respectively; p > 0.05) but lower when compared to the ovarian MAC (p < 0.01). The dogs recovered from anesthesia without complications. Conclusions and clinical relevance The ovarian stimulation model is an adequate and repeatable means of producing visceral stimulation to determine MAC. The model may provide a humane mechanism to study the effectiveness of analgesics for acute ovarian pain.     

Egg production forecasting: Determining efficient modeling approaches

Several mathematical or statistical and artificial intelligence models were developed to compare egg production forecasts in commercial layers. Initial data for these models were collected from a comparative layer trial on commercial strains conducted at the Poultry Research Farms, Auburn University. Simulated data were produced to represent new scenarios by using means and SD of egg production of the 22 commercial strains. From the simulated data, random examples were generated for neural network training and testing for the weekly egg production prediction from wk 22 to 36. Three neural network architectures-back-propagation-3, Ward-5, and the general regression neural network-were compared for their efficiency to forecast egg production, along with other traditional models. The general regression neural network gave the best-fitting line, which almost overlapped with the commercial egg production data, with an R(2) of 0.71. The general regression neural network-predicted curve was compared with original egg production data, the average curves of white-shelled and brown-shelled strains, linear regression predictions, and the Gompertz nonlinear model. The general regression neural network was superior in all these comparisons and may be the model of choice if the initial overprediction is managed efficiently. In general, neural network models are efficient, are easy to use, require fewer data, and are practical under farm management conditions to forecast egg production.     

Sawdust: Cost Effective Scavenger for the Removal of Chromium(III) Ions from Aqueous Solutions

Cr(III) ions sorption onto sawdust of spruce (Picea smithiana) has been studied thoroughly using radiotracer technique. Maximum sorption (94%) of Cr(III) ions (8.98×10^?5 M) onto sorbent surface is achieved from deionized water in 20 min agitation time using 200 mg of sawdust. The sorption data followed the Freundlich, Dubinin-Radushkevich (D-R) and Langmuir isotherms. Freundlich constants l/n = 0.86 ± 0.07 and C _e = 85.0 ± 25.8 mmole g^?1 have been estimated. Sorption capacity, X _m = 0.82± 0.3 mmole g^?1, β = ?0.00356± 0.00017 kJ² mole^?2 and energy, E = 11.9± 0.3 kJ mole^?1 have been evaluated using D-R isotherm. The Langmuir constants Q = 5.8± 0.2 μmole g^?1 and b = (7.4± 0.5)×10⁴ dm³ mole^?1 have been calculated. The variation of sorption with temperature yields thermodynamic parameters Δ H = ?11.6± 0.3 kJ mole^?1, Δ S = ?16.2± 0.9 J mole^?1 K^?1 and Δ G = ?6.8± 0.3 kJ mole^?1 at 298 K. The negative value of enthalpy and free energy reflect the exothermic and spontaneous nature of sorption respectively. Among the anions studied oxalate, citrate, carbonate and borate have reduced the sorption. The cations Y(III), Ce(II) and Ca(II) suppressed sorption. The sawdust column can be used to separate Cr(III) ion from Cs(I), I(I),Tc (VII) and Se (IV).     

Development of Empirical Formulae to Determine Emission Rate from Various Opencast Coal Mining Operations

All major mining activities, particularly opencast coal mining,directly or indirectly contribute to the problem of air pollution.Therefore, air quality assessment and prediction arerequired to prevent and minimize the air quality deteriorationdue to various opencast coal mining operations. Determination ofemission rates for these activities is the first and foremostconcern. In view of the above, this study was undertaken to determinate emission rates and to develop empericalformulae to calculate emission rates of various opencast coalmining activities.To achieve the objectives, seven coal mining sites were selectedto generate site-specific emission data by considering miningpractices, method of working, geographical location,accessibility and above all resourceavailability. The study covers various mining activities andlocations including drilling, overburden loading and unloading,coal loading and unloading, the coal handling plant, the exposedoverburden dump, the stock yard, the workshop, the exposed pit surface roadsand haul roads.Based on the study, a set of twelve emperical formulae have beendeveloped for calculation of suspended particulate matter (SPM)emission rates from various opencast coal mining activities. Theemission of gaseous pollutants (sulphur dioxide and nitrogenoxide) has been found negligible for various mining activities.Therefore, observation for gaseous pollutants has been consideredfor overall mine activities and empirical formulae have subsequently beendeveloped.The developed empirical formulae were calculatedby a field study at another coal mine. The measured andcalculated values of emission rate were compared for eachactivity. Average correlation between the measured andcalculated values for different activities was estimated to be 85.6–99.9%, which indicates fairly good accuracy.Validation of the study was also carried out by means of thefugitive dust model (FDM) using the calculated emissionrate data from the empirical formulae for each mining activity of amine, meteorological data and other details as input.The average accuracy between measured and predictedvalues of concentration of SPM at certain receptor locations wasfound to be 79%. A user-friendly emission software called`EmissCalc' was developed to calculate emission rate, whichcan be used as input for different air quality models.     

Thiamine (vitamin B1) seed treatment enhances germination and seedling growth of bean (Phaseolus vulgaris L.) exposed to soaking injury

Seed treatment with thiamine mononitrate significantly increased germination rate of bean (Phasenius vulgaris L.) seedlings germinated at high soil moisture levels and low night-temperature (5° C). Beneficial effects of thiamine applications on germination were also observed in soil-free germination tests when the seeds were submerged in water for 1–4 d at 18°C. Optimum response was achieved at thiamine concentrations of 3 mM, applied during the first 24 h of imbibition. As an early response to the thiamine treatment, vital staining with triphenyltetrazolium chloride revealed a lower proportion of damaged tissue of the embryonic axes. In later stages of seedling development, thiamine seed treatment resulted in a lower proportion of abnormal seedlings with malformations of the shoot apex and of the primary leaves. The beneficial effect of thiamine was more pronounced when the temperature during submergence was kept at 25° C compared to 5° C. There was no response to thiamine applications when the germinating seeds were exposed to low temperature treatments only. The thiamine effect could be mimicked by raising the osmotic potential of the incubation medium, indicating a relationship to soaking injuries. The results suggest that normal seedling development may be impaired by thiamine deficiency in the embryonic tissue induced by soaking injury, whereas low temperatures are not involved as a stress-factor.