VARIATION IN SUMMER DORMANCY AMONG COLLECTIONS OF PHALARIS TUBEROSA AT DAVIS, CALIFORNIA

The summer-donnancy period among collections of Phalaris tuberosa L. from the eastern Mediterranean region when grown at Davis, California, ranged from 30 to 127 days. Plants from the more arid sites of origin tended to exhibit the longer dormancy. There were exceptions, however, and these, together with the diversity of behaviour in this material, suggest that genotypes with a potential for increased summer growth may be selected for use on rangelands.     

Tail Muscle Free Amino Acid Concentration of Pacific White Shrimp,Litopenaeus vannamei,Fed Diets Containing Protein‐bound versus Crystalline Amino Acids

Tail muscle tissue free amino acids (FAA) concentration is reported for subadult (4.3 g) Litopenaeus vannamei fed diets containing only protein‐bound amino acids, crystalline lysine as a supplement to protein‐bound lysine, and only crystalline amino acids (CAA). FAA were determined in shrimp at 0.00, 0.25, 0.5, 1, 2, 4, and 8 h postfeeding. Highest total tissue concentrations of essential amino acids and individual amino acids were typically observed 4 h postfeeding for shrimp fed intact and crystalline lysine‐supplemented feeds. Those shrimp offered diets containing only CAA showed no tissue maxima. Similar uptake patterns for lysine shown by shrimp fed the intact and crystalline lysine‐supplemented diet indicate the potential use of small amounts of crystalline lysine in shrimp feeds.     

Correlation of fluridone and dye concentrations in water following concurrent application

Herbicide residue samples are expensive and time-consuming to collect and analyze. To test whether Rhodamine WT dye could simulate the dissipation of fluridone, concurrent applications of the chemicals were made in the weed-infested Three Sisters tidal canals (Citrus Co. Fl) and a shallow lake in the Upper St Johns River, Florida. Dye concentrations were measured using a field fluorometer and fluridone concentrations were analyzed by an HPLC method. The coefficient of correlation between dye and herbicide was 0.99 in the canals and 0.93 in Lake Hell ‘n’ Blazes (Upper St Johns River) over 340 and 93 h respectively. Half-lives of the chemicals were not significantly different for either site. The importance of these data in relation to herbicide registration is discussed.     

Effects of preemptive atropine administration on incidence of medetomidine-induced bradycardia in dogs

OBJECTIVE: To determine the cardiorespiratory effects of preemptive atropine administration in dogs sedated with medetomidine. DESIGN: Randomized crossover trial. ANIMALS: 12 healthy adult dogs. PROCEDURES: Dogs underwent 6 treatments. Each treatment consisted of administration of atropine (0.04 mg/kg [0.018 mg/lb] of body weight, IM) or saline solution (0.9% NaCl, 1 ml, IM) and administration of medetomidine (10, 20, or 40 microg/kg [4.5, 9.1, or 18.2 microg/lb], IM) 10 minutes later. Treatments were administered in random order, with a minimum of 1 week between treatments. Cardiorespiratory effects before and after atropine and medetomidine administration were assessed. Duration of lateral recumbency and quality of sedation and recovery were assessed. RESULTS: Bradycardia (heart rate < 60 beats/min) was seen in all dogs when saline solution was administered followed by medetomidine, and the dose of medetomidine was not associated with severity or frequency of bradycardia or second-degree heart block. However, a medetomidine dose-dependent increase in mean and diastolic blood pressures was observed, regardless of whether dogs received saline solution or atropine. Preemptive atropine administration effectively prevented bradycardia and second-degree heart block but induced pulsus alternans and hypertension. The protective effects of atropine against bradycardia lasted 50 minutes. Blood gas values were within reference limits during all treatments and were not significantly different from baseline values. Higher doses of medetomidine resulted in a longer duration of lateral recumbency. CONCLUSIONS AND CLINICAL RELEVANCE: Preemptive administration of atropine in dogs sedated with medetomidine effectively prevents bradycardia for 50 minutes but induces hypertension and pulsus alternans.     

Intraosseous approach to the nasolacrimal duct for removal of a foreign body in a dog

A Labrador retriever was evaluated because of chronic mucopurulent discharge from the left eye. A foreign body was identified in the nasolacrimal duct by use of dacryocystorhinography. Attempts to alleviate the inflammation by use of flushing and administration of antimicrobials were unsuccessful. At surgery, the infraorbital foramen was used as a landmark for a skin incision, because the nasolacrimal duct courses dorsal and parallel to the infraorbital canal. An air drill was used to remove the portion of the maxillary bone overlying the nasolacrimal duct, which exposed the intraosseous portion of the duct and allowed removal of a plant-material foreign body. The incision in the duct was allowed to heal by second intention, and the dog recovered without complications.     

The amino acid profiles of the whole plant and of four plant residues from temperate and tropical forages

This study compared the amino acid (AA) profile of five residues (original forage, borate-phosphate buffer residue (BPR), neutral detergent fiber residue with (NDF+) and without (NDF-) sodium sulfite, and acid detergent fiber residue (ADF). Fourteen grasses and legumes from tropical and temperate regions were used in this study. The use of sodium sulfite did not affect the NDF concentration, but the NDF insoluble protein was lower (P < 0.05) in the NDF+ than in the NDF- (3.9 vs 4.5% DM, respectively). For all of the amino acids tested, the amino acid content, expressed as a percentage of CP, was lower in the ADF residue than in the original forage. There were no differences in the amino acid concentrations of the NDF- and NDF+ extracts (P > 0.05). Only in the case of methionine was there a difference in the amount of amino acid when the original forage was compared with the BPR (1.84 vs 1.45 % CP). When the AA profile of each residue was corrected for the AA content of the ADF, no difference was observed between the AA profile of the original forage and of the BPR (P > 0.05). Similar to the result without correction for the amino acids in ADF, the AA profiles of the NDF+ and NDF- fractions were similar (P > 0.05). From this result, we infer that the sodium sulfite had similar effects on all AA in the NDF residue that we tested. There were differences in amino acid concentrations in the original forage and the NDF residues for several amino acids (Met, Cys, Lys, Thr, Arg, Ile, Leu, and Phe) (P < 0.05). When the amino acid values of the original forage and the BPR were used with animal data in the Cornell Net Carbohydrate and Protein System model, few differences in animal predicted performance were evident. These findings suggest that the AA profile of the original forage can be used to predict the AA profile of the undegraded intake protein instead of using the borate-phosphate buffer residue for amino acid analyses. This would simplify obtaining feed amino acid values for use in the Cornell Net Carbohydrate and Protein System.     

核盘菌在亚麻上侵染致病的微观过程

 第1次利用电子显微镜对核盘菌在亚麻叶片上侵染致病的微观过程进行深入细致的观察。结果表明,该菌在侵入叶表面之前可能产生某些酶类物质来软化溶解亚麻叶表面角质层,以帮助该菌对叶表面的侵入。本文还对菌丝和子囊孢子侵染过程的异同进行了比较。     

Diversity of microbial products—discovery and application

Natural products derived from micro-organisms, plants and animals possess inherent biological properties and are, therefore, an excellent source of lead chemicals on which to base synthesis programmes employing rational design techniques. Only a fraction of the fungal kingdom has been screened systematically for novel metabolites despite their suspected potential. Moreover, the fungi are generally manipulable in laboratory culture systems and, because of their developmental versatility, they offer tremendous potential as sources of novel metabolites. Primary assay systems based on biochemical targets provide an effective means of screening microbial products; such assay systems also efficiently support chemical purification of lead activities and rapid elucidation of new chemical templates.