Impacts of soil moisture level and organic matter content on growth of two Juncus species and Poa pratensis grown under acid soil conditions

The abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) has increased in coastal grasslands in Norway over recent decades, and their spread has coincided with increased precipitation in the region. Especially in water‐saturated, peaty soils, it appears from field observations that productive grasses cannot compete effectively with such rapidly growing rush plants. In autumn–winters of 2012–2013 and 2013–2014, a four‐factor, randomised block greenhouse experiment was performed to investigate the effect of different soil moisture regimes and organic matter contents on competition between these rush species and smooth meadow‐grass (Poa pratensis). The rush species were grown in monoculture and in competition with the meadow‐grass, using the equivalent of full and half the recommended seed rate for the latter. After about three months, above‐ and below‐ground dry matter was measured. J. effusus had more vigorous growth, producing on average 23–40% greater biomass in both fractions than J. conglomeratus. The competitive ability of both rush species declined with decreasing soil moisture; at the lowest levels of soil moisture, growth reductions were up to 93% in J. conglomeratus and 74% in J. effusus. Increasing water level in peat–sand mixture decreased competivitiveness of meadow‐grass, while pure peat, when moist, completely impeded its below‐ground development. These results show that control of rush plants through management may only be achieved if basic soil limitations have been resolved.     

鹿蹄草等中草药对油桃采后褐腐病抑制效果研究

在离体和活体条件下,测定鹿蹄草、厚朴等中草药单剂及鹿蹄草为主的各中草药复配组合对油桃采后褐腐病菌的抑制效果。结果表明:11号(鹿蹄草+厚朴+大黄),14号(鹿蹄草+高良姜+虎杖)复配组合在离体试验中抑菌效果最好,10 mg/mL浓度的抑制率分别达到89.77%,85.50%;两种组合的最小抑菌浓度(MIC)分别是1.25,2.5 mg/mL;最小杀菌浓度(MBC)分别是2.5,5.0 mg/mL。活体抑菌测定结果表明,11号和14号复配组合对油桃褐腐病菌有不同程度延缓侵染和抑制作用,但不能完全防治;0.05 mg/mL扑海因与11号组合20 mg/mL,0.10 mg/mL扑海因与11号组合10 mg/mL均能完全抑制褐腐病菌在油桃果实上的发生和蔓延。     

Influence of age and testosterone levels on masculine development in rams

Fifty wethers and 51 spring-born rams were divided into five groups and slaughtered at different seasons of the year at average ages of 271, 361, 459, 557 or 652 d to determine the age and season at which differences in secondary sex characteristics could be detected. Serum testosterone concentrations and testes weights were low in January when the rams were 271 d of age and again in April at 361 d of age. By July, at 459 d of age, testosterone concentrations and testes weights had peaked and then decreased the following November at 557 d and February at 652 d. In contrast with plasma testosterone concentrations and testes weights, buckiness scores, splenius to semimembranosus or semitendinosus muscle ratios, splenius muscle weights and neck and shoulder percentages were not seasonal. All of these measures increased significantly up to July and continued to increase slowly, but not significantly, thereafter. Muscle color and texture scores and rib eye color scores tended to increase in a linear manner for both rams and wethers as age increased. Subcutaneous fat from rams was yellower and softer than that from wethers over all age groups. Ram fat firmness did not change (P greater than .05) with age, and the only significant change in ram fat color was between the groups at 271 and 361 d of age. Overall, season of year coupled with higher levels of serum testosterone was related to initial development of secondary sex characteristics in ram lambs.     

Inducible Flavone in Oats (Avena sativa) Is a Novel Defense Against Plant-Parasitic Nematodes

ABSTRACT The induction of defense compounds in oats (Avena sativa) in response to invasion by parasitic nematodes and to application of the wound hormone methyl jasmonate was examined. Oats cv. Quoll seedlings were challenged with Pratylenchus neglectus, Heterodera avenae, and Ditylenchus dipsaci and treated with 1 x 10(-4) M methyl jasmonate. Three compounds, isolated in methanolic root and shoot extracts of oats, exhibiting an absorbance spectrum typical of flavone glycosides, were induced by nematode invasion and methyl jasmonate. These were identified as flavone-C-glycosides by mass spectrometry. The effect of the flavone-C-glycosides on the invasion by and development of cereal cyst nematode H. avenae was assessed using methanolic extracts of shoots and roots from methyl jasmonate-treated plants. Both extracts impaired nematode invasion and development. When the extracts were fractionated by high voltage paper electrophoresis, only one flavone-C-glycoside, O-methyl-apigenin-C-deoxyhexoside-O-hexoside, inhibited nematode invasion. The protective effect of the induction of flavone-C-glycosides in oats by methyl jasmonate was evaluated against H. avenae and P. neglectus. Treatment with methyl jasmonate reduced invasion of both nematodes and increased plant mass, compensating for damage caused by the nematodes, and is attributed to the active flavone-C-glycoside. The active compound, O-methyl-apigenin-C-deoxyhexoside-O-hexoside, has not been implicated previously in plant defense against any pest or pathogen, and appears to provide protection against the major cereal nematodes Heterodera and Pratylenchus.     

Detection of cell detachment activity induced by Moraxella bovis

OBJECTIVE: To characterize the effect that filtrate obtained from cultures of Moraxella bovis has on cultured corneal epithelial cells and other types of cultured mammalian cells. SAMPLE POPULATION: Cultured hamster corneal epithelial cells, bovine epithelial cells, and several transformed cell lines exposed to culture filtrate from a pathogenic isolate of M bovis. PROCEDURE: Moraxella bovis was cultured, and bacteria were removed by filtration. The resulting bacterial culture filtrate was incubated with various types of cultured cells, and effects of the filtrate on detachment of various mammalian cell types was quantified by the use of neutral red dye. Additionally, bacterial culture filtrate was treated with protease inhibitors as well as trypsin and heat prior to incubation with cultured mammalian cells. RESULTS: Bacterial culture filtrate of M bovis caused all types of cultured cells to detach from each other and from the substrate, with the maximal effect evident 2 hours after initiating incubation. Detached cells were alive, and detachment was reversible. Serine protease inhibitors (phenylmethylsulfonylfluoride and alpha2-macroglobulin) inhibited cell detachment attributable to bacterial culture filtrate. Heating and treatment with trypsin also inhibited cell detachment. CONCLUSIONS AND CLINICAL RELEVANCE: Moraxella bovis produces a soluble factor that causes reversible detachment of cultured cells. This activity may play a role in the pathogenesis of infectious bovine keratoconjunctivitis.     

Uptake and distribution of tritium-labeled polysulfated glycosaminoglycan in serum, urine, and superficial digital flexor tendon of rabbits after intramuscular administration

OBJECTIVE: To determine concentrations of tritiated polysulfated glycosaminoglycans (3H-PSGAG) in serum, urine, and the superficial digital flexor tendon (SDFT) of rabbits after IM administration and molecular weight of 3H-PSGAG recovered from the SDFT. ANIMALS: Twenty-five 12-week-old New Zealand White rabbits. PROCEDURE: Rabbits were given a single dose of 3H-PSGAG (1.1 mg/kg [70 mCi of specific activity/kg] of body weight) IM. At each of 5 sample times (2, 24, 48, 96, and 192 hours), 5 rabbits were randomly selected and sedated, and blood and urine samples were collected. Rabbits were then euthanatized, and the SDFT were immediately harvested from the hind limbs. Scintillation spectrometry was used to detect concentration of 3H-PSGAG in fluid and tissue samples. Gel-filtration chromatography was used to determine molecular weight of recovered 3H-PSGAG. RESULTS: Mean concentrations of 3H-PSGAG in SDFT, serum, and urine were greatest 2 hours after administration. Tritiated PSGAG could be detected in all samples collected 192 hours after administration. Gel-filtration chromatography confirmed that 3H-PSGAG detected in SDFT samples was high molecular weight PSGAG. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that PSGAG is distributed to the SDFT, serum, and urine after IM administration in rabbits. Further study is needed to determine whether the same is true in horses and to determine what effect, if any, PSGAG has on inflammation of the SDFT.