Phosphorus and molybdenum interaction effects during accumulation of molybdenum by burley tobacco 1

Greenhouse experiments were conducted to study the P and Mo interactions during uptake by burley tobacco (Nicotiana tabacum L., cv. ‘Ky 14') and the effect of their interactions on plant dry matter and Mo concentration. In Experiment 1, plants were grown in an intermittently irrigated gravel culture system. The nutrient variables were Mo (0–0.63 μeq/L) and P (0 to 1.8 meq/L). Experiment 2 was conducted in soil‐sand mixtures. The soil types used were Shelbyville silt loam (Mollic Hapludalf) and Baxter silt loam (Typic Paleudalf) each containing, respectively, 36 and 368 kg P/ha by the Bray 1 soil test. Treatments consisted of four rates of P (0, 84, 168, and 336 kg/ha) and five rates of Na₂MoO₄‐2H₂O (0, 0.56, 1.12, 2.24, and 4.48 kg Mo/ha).

In gravel culture a significant synergistic Mo × P interaction occurred for dry weight, but singly the effect of P was greater than Mo. Similarly, significant positive Mo × P interactions occurred for Mo concentrations in both gravel and soil culture. As contrasted to adding no P or Mo, adding the highest levels of P and Mo together increased Mo concentrations in leaves four, five, and 10 fold, respectively, in gravel culture, Shelbyville, and Baxter soils. The rate of accumulation of Mo was much greater at plant Mo concentrations above 1 μg Mo/g tissue than below, suggesting two mechanisms of Mo × P interaction were involved.     

The absorption of molybdenum by excised tobacco (nicotiana tabacum L.) roots 1

The absorption of 99‐Mo by excised tobacco, Nicotiana tabacum L. c.v. KY‐14, roots was examined. Lowered temperature, anaerobic conditions and various inhibitors of oxidative phosphorylation decreased the absorption of Mo, suggesting that the absorption of Mo was metabolism‐dependent. Similar results were obtained with the absorption of 86‐Rb. The absorption of 99‐Mo decreased exponentially with an increase in pH. The apparent Km for the absorption of Mo was 15 μM, although at high concentrations of Mo, the absorption of Mo occurs primarily by passive processes.     

Surgical removal of an abscess associated with Fusarium solani from a Kemp's ridley sea turtle (Lepidochelys kempii)

A cold-stunned Kemp's ridley sea turtle, Lepidochelys kempii, developed an abscess associated with Fusarium solani, Vibrio alginolyticus, and a Shewenalla species after receiving a bite wound to the front flipper during rehabilitation. The lesion failed to respond to medical therapy and was treated successfully with surgery. Histopathology of the excised tissue demonstrated septic heterophilic inflammation with necrosis and granulation tissue, fungal elements, and bacteria, despite appropriate antimicrobial therapy. Variably thick bands of dense collagenous tissue partially surrounded affected areas which might have limited drug penetration into the tissue. Postoperative healing and eventual releases were uneventful. This is the first report of surgical treatment of cutaneous Fusarium infection in a sea turtle and supports surgery as an effective treatment for a fungal abscess in a reptile.     

Genetic screening of FecB,FecXG and FecXI mutations and their linkage with litter size in Barki and Rahmani sheep breeds

Characterization of fecundity genes offers the opportunity to improve production efficiency, and the consequent increase in litter size in livestock industry, through utilizing them in breeding programs. The main objective of this study was to detect the BMPR‐IB, BMP15 and GDF9 gene mutations and to investigate whether these mutations are associated with litter size in Egyptian sheep breeds. To achieve this goal, 73 adult ewes representing Barki (n = 33) and Rahmani (n = 40) breeds were used. Polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) screening approach was used to detect the presence of FecB, FecX^G and FecX^I mutations in the two selected breeds. Results of this study showed that the three different candidate gene mutations, namely FecB, FecX^G and FecX^I are not present among these selected populations of the Egyptian breeds. Further studies regarding other mutations and/or other genes, which may influence ovulation rate, should be carried out to determine the type and mode of inheritance of such genes in Egyptian sheep breeds.     

Efficacy of levamisole and netobimin against Haemonchus contortus in lambs in Louisiana

Efficacy of levamisole was evaluated in a suspected levamisole-resistant population of Haemonchus contortus in the Louisiana State University sheep flock. The efficacy of netobimin also was evaluated against this population of Haemonchus. In trial 1, 5 lambs naturally infected with H contortus were given 8 mg of levamisole/kg of body weight as a drench, and 5 lambs were not treated (controls). Nematode recovery after slaughter indicated 0% efficacy against H contortus. In trial 2, 30 nematode-free lambs were each given 8,300 F1 generation infective larvae of H contortus, which were derived from parent H contortus that survived 2 levamisole treatments in lambs being maintained in a nematode-free environment. Ten lambs were treated with 8 mg of levamisole/kg as a drench, 10 were treated with 20 mg of netobimin/kg as a drench, and 10 were not treated (control). Nematode recovery after slaughter revealed 62.3% and 99.8% efficacy for levamisole and netobimin, respectively, against H contortus.     

Mastitis-metritis-agalactia complex in sows: effect of the dosage of oxytocin on intramammary pressure in lactating healthy sows

The dose-response and time-response relationships between injected oxytocin and intramammary pressure were investigated in normal lactating sows. In less than 39 s after 20, 40, or 80 U of oxytocin was given (IM injection), there was a rapid initial increase in intramammary pressure (15 to 27 mm of Hg) which lasted 22 to 32 s. After this initial response, there were secondary oscillations in pressure which lasted approximately 40 minutes (20 U) and up to 60 minutes (40 or 80 U). Changes in intramammary pressure during each oscillation varied between 1 and 5 mm of Hg. Mean values for frequency and amplitude of oscillations and total work (area under the trace) were measured. Compared with response obtained after 20 U of oxytocin was given, responses obtained at the 40-U or 80-U dose level had an increased frequency (150.0% and 249.0%, respectively) and total work (36.6% and 104.4%, respectively), but not amplitude. Thus, there may be some clinical advantage in milk let-down effect when sows are given the larger doses of oxytocin (40 or 80 U). These results indicate that newborn pigs should be allowed to nurse at the same time in which oxytocin is injected.     

Differences in composition of avian bone collagen following genetic selection for resistance to osteoporosis

1. Collagen characteristics were compared in the tibiotarsus and humerus from 103 females and 38 males aged 68 to 72 weeks from the G6 generation of lines of laying hen selected for resistance or susceptibility to osteoporosis (high and low bone index (BI) lines). 2. Selection over the latest generation resulted in further divergence in the breaking strengths of humerus (from 12.3 to 21.8%) and tibia (from 22.3 to 37.3%) in hens. Males also showed line differences in bone strengths. 3. Plasma pyridinoline concentration was higher in hens in the low BI line, suggesting a greater rate of bone resorption in this line. 4. There were few differences between the lines in collagen and calcium concentrations in humerus and tibiotarsus cortical bone. 5. There were no differences between the lines in either sex in reduced immature collagen cross-link content of humerus or tibiotarsus. 6. Mature collagen cross-link content was higher in the high BI line in the male humerus but this effect was not apparent in the male tibiotarsus nor in either bone in the females. 7. Pyrrolic cross-link contents were higher in the high BI line in the female humerus and tibiotarsus and in the male tibiotarsus. 8. Over both lines combined, there were positive correlations between humeral and tibiotarsal pyrrole contents and strengths in females and between tibiotarsal pyrrole content and strength in males. 9. It is concluded that an increase in cross-linking, particularly pyrrolic cross-linking, in the collagen matrix contributes in part to the improvement in bone strength in the high BI line.     

The role of learning in shark behaviour

The role of learning in behaviour is well known for many animal taxa, including teleost fishes, insects, birds and mammals. However, its importance to sharks in everyday behavioural processes has rarely been considered. Almost 50 years ago the first learning experiments on sharks were conducted; our first section discusses these studies and places them in a framework of associative and non‐associative learning. These experiments showed that sharks were capable of different forms of learning, such as operant and classical conditioning and habituation. Sharks could learn associations as rapidly as other vertebrates and also remember training regimes for several months. However, much of this experimental evidence was based on small sample sizes and few shark orders, such as Carcharhiniformes and Orectobliformes, leaving large gaps in our knowledge of the general learning capabilities of other shark orders. We also examine recent research that has tested for, or inferred learning in behavioural processes. This section reveals that sharks, like teleost fishes use learning to improve prey search and capture to potentially navigate and orientate in their home range and recognize conspecifics, heterospecifics and mates. Learning is also discussed in relation to ecotourism and fisheries. Findings indicated that these activities may lead to conditioning of sharks and that considerable effort should go into investigating what impact this could have on the shark species involved. Finally, we discuss the importance of combining laboratory experiments with field studies, the use of new experimental techniques, the role of model species and research priorities for future work.     

化脓棒状杆菌的分离与坚定

北京动物园的2头斑羚和1头岩羊相继发病死亡。剖检发现肺部均有淤血和化脓灶。经取其肺组织作细菌培养,均分离到纯粹的杆菌。经细菌形态、培养特性和生化特性分析,鉴定为化脓棒状杆菌。