Effect of antagonistic<Emphasis Type="Italic">Fusarium</Emphasis> spp. and of different commercial biofungicide formulations on Fusarium wilt of lettuce

Five experimental trials were carried out to test different biological control agents against Fusarium wilt of lettuce, cause byFusarium oxysporum f.sp.lactucae. In the presence of a very high disease incidence, the best results in terms of disease control as well as increased growth response were shown byTrichoderma harzianum T 22 (RootShield), which, at 3 gl ⁻¹ of substrate, provided very consistent results.F. oxysporum IF 23 gave good disease control but in two out of five trials reduced the biomass produced. Less consistent, but still significant results were provided byF oxysporium MSA 25, at 3 gl ⁻¹ of substrate, and byTrichoderma viride TV 1. The twoF. oxysporum agents Fo 251/2 and Fo 47 and the mixture ofT. harzianum + T. viride (Remedier) partially reduced disease incidence but were less effective than the above mentioned. Less interesting results were offered byStreptomyces griseoviridis (Mycostop). The results obtained show that biological control can play a role in the management of Fusarium wilt of lettuce.     

The hymenopteran parasitoids of some elm bark beetles in Serbia

The parasitoids of the elm bark beetlesScolytus ensifer, S. kirschi, S. multistriatus, S. pygmaeus andPteleobius vittatus were studied in ten localities in Serbia. Eleven species of parasitoids ofS. ensifer, 10 ofS. kirschi, 13 ofS. multistriatus, 12 ofS. pygmaeus, and four ofP. vittatus were found. The most abundant wereEcphylus silesiacus, Dendrosoter protuberans, Cheiropachus quadrum andRhaphitelus maculatus. Acrocormus semifasciatus, Cerocephala eccoptogastri, Mesopolobus typographi andDoryctes pomarius were found in some samples. http://www.phytoparasitica.org posting May 4, 2007     

额济纳绿洲柽柳灌丛辐射特征与热量平衡研究

根据黑河下游额济纳绿洲柽柳灌丛波文比-能量平衡法的实测资料,分析了该地区的辐射特征,研究了热量平衡各分量的变化特征及热量平衡规律。在绿洲内部,其太阳辐射、净辐射具有明显的日进程和季节变化规律;太阳辐射月总量最大值(2133325.0kW.m-2)出现在6月份,最小值(133325.0kW.m-2)出现在10月份;在柽柳灌丛生态系统的热量平衡中潜热通量占能量支出量的62.85%,感热通量占32.85%,土壤热通量占4.44%。在日变化中,潜热在上午大于感热,在下午,由于湍流加剧,感热交换大于潜热。     

Photosynthetic and growth responses of juvenile Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) to waterlogging and water deficit

Chinese kale (Brassica oleracea var. alboglabra) and Caisin (Brassica rapa subsp. parachinensis) are leafy vegetable crops grown in south-east Asian countries where rainfall varies dramatically from excess to deficit within and between seasons. We investigated the physiological and growth responses of these plants to waterlogging and water deficit in a controlled experiment in a glasshouse. Juvenile plants were subjected to waterlogging or water deficit for 19 days in case of Chinese kale and 14 days in case of Caisin and compared with well-watered controls. Caisin tolerated waterlogging better than Chinese kale because it produced hypocotyl roots and gas spaces developed at the stem base. In Chinese kale, waterlogging reduced plant fresh weight (90%), leaf area (86%), dry weight (80%) and leaf number (38%). In contrast, waterlogging had no impact on leaf number in Caisin and reduced plant fresh and dry weights and leaf area by 60–70%. Water deficit reduced leaf area, fresh weight and dry weight of both species by more than half. Leaf number in Chinese kale was reduced by 38% but no effect occurred in Caisin. Water deficit increased the concentration of nitrogen in the leaf dry matter by more than 60% in both species and the leaf colour of water deficient plants was dark green compared with the leaf colour of well-watered plants. Soil water deficit delayed flowering of Caisin while waterlogging accelerated it. Thickening and whitening of the cuticle on the leaves of Chinese kale probably increased its ability to retain water under drought while Caisin adjusted osmotically and Chinese kale did not. Waterlogging and water deficit had strong effects on leaf gas exchange of both Brassica species. Water deficit closed the stomata in both species and this was associated with a leaf water content of 9 g g⁻¹ DW. In contrast, waterlogging reduced conductance from 1.0 to 0.1 mol H₂O m⁻² s⁻¹ in direct proportion to changes in leaf water content, which fell from 11 to 5 g g⁻¹ DW. This separation of the effects of water deficit and waterlogging on conductance was reflected in transpiration, internal CO₂ concentration and net photosynthesis. In conclusion, Chinese kale and Caisin showed rather different adaptations in response to waterlogging and water deficit. Caisin was more tolerant of waterlogging than Chinese kale and also showed evidence of tolerance of drought. There is genetic variation to waterlogging within the Brassica genus among the leafy vegetables that could be used for cultivar improvement.     

Assessment of genetic diversity of Highland bananas from the National Banana Germplasm Collection at Rubona,Rwanda using RAPD markers

The genetic similarities of 49 accessions of bananas from The National Banana Collection at Rubona were investigated using random amplified polymorphic DNA markers. A total of 120 primers were screened for their usefulness in amplifying DNA fragments of four cultivars belonging to the subgroup Mutika–Lujugira. Fifteen random primers were selected for more detailed analysis, on the basis of providing reproducible amplification and revealing a high level of variation between the four cultivars. The genetic similarity was estimated using a simple matching coefficient which showed the lowest value of 0.46 between ‘Ingumba’ and ‘Ishika’ and the highest value of 0.85 between ‘Kirayenda’ and ‘Inyabukuwe’. The data of matrix of coefficient of similarity was subjected to cluster analysis using the unweighted pair group method with arithmetic average (UPGMA). Each accession was clearly separated. The results of this study are important for the curation of the banana germplasm collection in Eastern Central Africa and for future breeding of this crop.     

越橘基因组DNA的快速提取及分析

为了从富含多酚、多糖及色素的越橘叶片中提取适用于分子生物学研究的高质量基因组DNA。以越橘幼叶为实验材料,比较了CTAB、SDS、高盐低pH值3种提取方法,获得了一种以CTAB法为基础的分离高质量完整DNA的简便、快速方法。用紫外分光光度计、琼脂糖凝胶电泳、RAPD-PCR、酶切等方法对获得的DNA进行了分析,结果表明,快速CTAB法所提取的DNA产量高、质量好,完全能够满足RAPD、PCR等分子生物学实验的要求。     

Screening of two probiotic products for use in fermented liquid feed

In this trial two commercial probiotic products (Bactocell® and Adjulact® Pro) were investigated in vitro for their use as microbial inoculum for the production of fermented liquid feed (FLF) for pigs. Bactocell® was applied at a dose of 9 and 10 log₁₀ CFU/kg and Adjulact® Pro at a level of 9 log₁₀ CFU/kg. The FLF (control and treatments) was prepared with a water to feed ratio of 4:1 and run in batch for 72 h at 30 °C. The microbial population was followed with plate countings and the lactic acid, acetic acid and ethanol concentration was determined at different time points in the FLF. After 24 h, significant differences (P < 0.05) were found between the control and the Adjulact® Pro FLF for pH (4.7 vs 4.3), lactic acid (57.9 vs 91.5 mmol/L), acetic acid (23.1 vs 6.8 mmol/L), ethanol (24.5 vs 1.1 mmol/L), coliforms (7.2 vs 4.3 log₁₀ CFU/mL) and E. coli (6.2 vs 4.4 log₁₀ CFU/mL). Bactocell® addition did not alter the fermentation characteristics compared to the control FLF. After 72 h no significant differences between treatments were noted, except for the yeast count which was higher in the FLF inoculated with Adjulact® Pro.     

Dissemination and tracking of Salmonella spp. in integrated broiler operation

Controlling Salmonella in integrated broiler operation is complicated because there are numerous potential sources of Salmonella contamination, including chicks, feed, rodents, wild poultry operations, and the processing plant. The objective of this study was to investigate the distribution of Salmonella through all phases of two integrated broiler operations and to determine the key areas related to the control of all known sources of infection. Two different Salmonella serotypes were observed at integrated broiler chicken company A. S. enteritidis, the predominant company A isolate, was consistently found in the breeder farm, hatcheries, broiler farms, and chicken slaughterhouse. At company B, a total of six different serotypes, S. heidelberg, S. senftenberg, S. enteritidis, S. blockley, S. gallinarum, and S. virchow, were detected. Although S. heidelberg was not found in the broiler farms, it was consistently found in the breeder farm, hatcheries, and chicken slaughterhouse. In addition, S. enteritidis was found in the hatcheries, broiler farm, and chicken slaughterhouse. In order to obtain the genetic clonality, 22 S. enteritidis isolates were digested with XbaI and analyzed by pulsed-field gel electrohporesis (PFGE). A difference in the PFGE pattern was found to be related to the origin of the integrated broiler operation. These data support the critical need to control Salmonella in breeder farms and hatcheries, and demonstrate important points related to the control of infection in large-scale poultry operations of Korea.     

An overview of potentially life-threatening poisonous plants in dogs and cats

Objectives: This article discusses the toxicity of the most common poisonous plants known to cause life‐threatening systemic effects or death in dogs and cats as reported to the ASPCA Animal Poison Control Center (APCC). Data sources: The article presents an overview of geographic distribution, toxic principle, clinical signs, clinical chemistry alterations, and treatment of intoxication as reported in the literature and based upon data retrieved from the APCC between January 2001 and December 2003. Summary: Most plant exposures in dogs or cats result in mild to moderate signs of vomiting and diarrhea while liver, kidney, central nervous system, or cardiovascular effects are rare. Some garden or household plants can cause serious systemic effects or death when a small amount of plant material has been ingested. Based on APCC records, the most frequently reported poisonous plants causing serious systemic effects include Lily (Lilium and Hemerocallis spp.), Azalea (Rhododendron spp.), Oleander (Nerium oleander), Sago palm (Cycas spp.), Castor bean (Ricinus communis), Kalanchoe (Kalanchoe spp.), and Autumn Crocus (Colchicum autumnale). Conclusion: Despite the variety of toxins present in the plants listed above, early clinical signs of toxicosis in dogs and cats can be nonspecific and can include vomiting, lethargy, anorexia, salivation, or diarrhea. Cardiac arrhythmias may be present with oleander, azalea, or kalanchoe ingestion. Evidence of liver or kidney damage (Cycas, Lilium, Hemerocallis spp., Ricinus communis) may occur 1–2 days after the exposure. Treatment consists of early decontamination and supportive care and may vary according to the type of plant involved and clinical signs present.     

A comparison of two dose levels of antibiotics for intramammary treatment of clinical mastitis in cows

A clinical trial was conducted in Nordre Valdres, Norway, to examine the effect of a low-level vs. a high-level intramammary antibiotic treatment of clinical mastitis. It was also of interest to identify significant risk factors and to estimate the probability of no recovery for given defined levels of risk factors. Quarter milk samples from 166 cows with clinical mastitis were examined before and after treatment, at 3 weeks interval. The two treatment levels did not differ significantly with respect to recovery rate. The probability of no recovery could be estimated by using information on the severity of general clinical signs, lactation number, bacteriological findings, and quarter location.