接种茄病镰刀菌(Fusarium solani f.sp.glycines)对不同基因型大豆植株和须根的影响

摘要：茄病镰刀菌（Fusarium solani f．sp．glydne）是一种土生细菌,通过侵染大豆根系引发猝死综合症。利用温室盆栽试验和须根培养试验研究了接种茄孢镰刀菌对13个不同基因型大豆的影响。结果表明：接种后所有盆栽大豆主根都有明显深褐色的侵染病斑;移植后21d测定了盆栽植株叶部发病程度,Peking表现最为严重,然后依次为Spencer,Ripley,P3981,Williams82,Essex,Forrest,Iroquois,PI520733,Hartwig,PI567650B,Jack,和PI567374。叶部发病程度与冠高（r=-0．422,P=0．0018）、冠重（r=-0．857,P〈0．0001）和根重（r=-0．732,P〈0．0001）呈显著负相关。主根病斑长度与叶部发病程度没有相关性,表明大豆对病原菌的抗性不能仅通过根系得到充分控制。对培养的大豆须根接种茄病镰刀菌菌丝体10d后,不同基因型大豆的菌落直径的变化范围为17—40mm,差异显著（P=0．05）,其中Spencer和Peking须根上的菌落直径显著（P=0．05）大于PI567374和PI520733。对Spencer和PI567374的须根接种10灿茄病镰刀菌常量成分悬浮液,10d后菌落直径分别为50和38mm,差异显著（P=0．05）。通常,不同基因型大豆间茄病镰刀菌在培养须根上的生长与整株的症状间有一定的相关性,但不总是这样,这是因为即使根系对毒素产生抗性来减少叶部病害症状,但并不是所有的大豆都表现出明显的根系抗性。     

Multiplex real-time PCR for the detection and differentiation of equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4)

A multiplex real-time PCR was designed to detect and differentiate equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4). The PCR targets the glycoprotein B gene of EHV-1 and EHV-4. Primers and probes were specific to each equine herpesvirus type and can be used in monoplex or multiplex PCRs, allowing the differentiation of these two closely related members of the Alphaherpesvirinae. The two probes were minor-groove binding probes (MGB) labelled with 6-carboxy-fluorescein (FAM) and VIC for detection of EHV-1 and EHV-4, respectively. Ten EHV-1 isolates, six EHV-1 positive clinical samples, one EHV-1 reference strain (EHV-1.438/77), three EHV-4 positive clinical samples, two EHV-4 isolates and one EHV-4 reference strain (EHV-4 405/76) were included in this study. EHV-1 isolates, clinical samples and the reference strain reacted in the EHV-1 real-time PCR but not in the EHV-4 real-time PCR and similarly EHV-4 clinical samples, isolates and the reference strain were positive in the EHV-4 real-time PCR but not in the EHV-1 real-time PCR. Other herpesviruses, such as EHV-2, EHV-3 and EHV-5 were all negative when tested using the multiplex real-time PCR. When bacterial pathogens and opportunistic pathogens were tested in the multiplex real-time PCR they did not react with either system. The multiplex PCR was shown to be sensitive and specific and is a useful tool for detection and differentiation of EHV-1 and EHV-4 in a single reaction. A comprehensive equine herpesvirus disease investigation procedure used in our laboratory is also outlined. This procedure describes the combination of alphaherpesvirus multiplex real-time PCR along with existing gel-based PCRs described by other authors.     

Are cell redox or lactate dehydrogenase kinetics responsible for the absence of gluconeogenesis from lactate in sea raven,hepatocytes?

Previous studies have reported very low rates of gluconeogenesis from lactate in sea raven (Hemitripterus americanus) hepatocytes compared to other teleosts studied. This study examines whether hepatic cell redox or lactate dehydrogenase (LDH) characteristics may explain this observation. Sea raven hepatic optimal LDH activities (pyruvate reductase direction) were more than 40 times less compared with rainbow trout liver values (40 vs 1914 μmol·min⁻¹·g⁻¹ protein). The Km(lactate) was 9.24 and 0.86 mM for sea raven and trout hepatic LDH, but the Km(pyruvate) was similar between the two species (0.11 and 0.21 mM, respectively). These results suggested that sea raven liver LDH did not favour lactate use and was more indicative of the mammalian M-isozyme. Gel electrophoresis showed a predominant intermediate isozyme, with a small amount of the M-type LDH. Phosphoenolpyruvate carboxykinase (PEPCK) was localized to the mitochondrial compartment, while there was no apparent mitochondrial glutamate-oxaloacetate transaminase (GOT) activity. No in vitro lactate flux to glucose was found in untreated, 10 mM ethanol-treated, or 3 mM NH₄Cl-treated sea raven hepatocytes, although CO₂ production from lactate was decreased by ethanol and increased by NH₄Cl. These results provide evidence that cell redox does not limit gluconeogenesis from lactate, while low activities and the kinetic characteristics of LDH may partially explain the low lactate gluconeogenesis reported in sea raven hepatocytes. To whom correspondence should be addressed at University of Ottawa.     

Identification of genetic regions associated with black point in barley

Black point (BP) can cause severe losses to the barley industry through downgrading and discounting of malting barley. The genetic improvement in BP resistance of barley is complex, requiring reliable screening tools, an understanding of genotype by environment interactions and an understanding of the biochemical mechanisms of melanisation involved in BP development. Thus the application of molecular markers for resistance to BP may be a useful tool for plant breeders. We have investigated the genetic regions associated with BP resistance in the barley F₂ population, Valier/Binalong. Quantitative trait loci (QTLs) contributed by the resistant parent Valier, were detected on chromosomes 2HS, 2HC, 3HL, 4HL and a QTL contributed by the susceptible parent, Binalong was detected on 5HL. Three of the four QTLs were detected in two distinctly different environments. The differences observed in BP resistance between these two environments and the implications for accelerated screening are discussed. Identified SSR markers in these regions may be useful for selecting black point resistance in related breeding materials.     

Treatment of dogs with oral melanoma by hypofractionated radiation therapy and platinum-based chemotherapy (1987-1997)

This retrospective study in 39 dogs with incompletely resected oral melanoma examined the efficacy of hypofractionated radiation therapy and platinum-containing chemotherapy. All dogs were completely staged, with the majority of dogs classified as stage 1. Dogs received 6 weekly fractions of 6-gray (Gy) megavoltage irradiation with a cobalt-60 unit or a 4-MeV (megaelectron volts) linear accelerator. Dogs received cisplatin (10-30 mg/m2 IV) or carboplatin (90 mg/m2 IV) chemotherapy 60 minutes before radiation delivery. Durations of local control, metastasis-free survival time, and overall survival time were recorded. By the Kaplan-Meier method, 15% of the dogs had local recurrence within a median time of 139 days. Fifty-one percent of the dogs developed metastatic disease within a median time of 311 days (range, 24-2, 163 days). Median survival time for all 39 dogs was 363 days. The combined use of chemotherapy and radiation therapy in this protocol provided local control consistent with previous studies. Low-dose chemotherapy was used with the intent of enhancing radiation therapy for the local control of an incompletely excised tumor. Survival times were longer than previously reported for dogs with oral malignant melanoma. Additional studies are required to determine whether these results were due to the effects of chemotherapy on microscopic disease or the enhanced local control provided by chemoradiation therapy.     

Physiological Responses of Rainbow Trout Oncorhynchus mykiss to Crowding and Anesthesia with AQUI-S™

Abstract.— Following exposure to the anesthetic AQUI-S™, plasma cortisol concentration in immature rainbow trout was measured as (mean) 293 ± 48 ng/ mL, which was significantly ( P > 0.05) higher than the mean concentration in resting fish. Cortisol concentrations remained significantly ( P > 0.05) elevated for at least 24 h after treatment. This was accompanied by a significant increase and decrease in hematocrit and plasma potassium, respectively. These perturbations continued for at least 48 h following recovery from anesthesia. Plasma concentrations of total protein and sodium remained unchanged following anesthesia with AQUI-S™. Crowding stress is commonly encountered by fish during manipulation in aquaculture situations. Anesthetising fish prior to, and during, manipulation may reduce the associated stress. Changes in cortisol values resulting from crowding (30 min; 0.1 kg/L) during anesthesia with AQUI-S™ were not appreciably different from those in fish crowded without anesthesia. Thus, anesthesia with AQUI-S™ at the recommended dose of 17 mg/L did not appear to be effective for alleviating the stress of crowding under the conditions of our experiments.     

Soybean mosaic virus Helper Component-Protease Alters Leaf Morphology and Reduces Seed Production in Transgenic Soybean Plants

ABSTRACT Transgenic soybean (Glycine max) plants expressing Soybean mosaic virus (SMV) helper component-protease (HC-Pro) showed altered vegetative and reproductive phenotypes and responses to SMV infection. When inoculated with SMV, transgenic plants expressing the lowest level of HC-Pro mRNA and those transformed with the vector alone initially showed mild SMV symptoms. Plants that accumulated the highest level of SMV HC-Pro mRNA showed very severe SMV symptoms initially, but after 2 weeks symptoms disappeared, and SMV titers were greatly reduced. Analysis of SMV RNA abundance over time with region-specific probes showed that the HC-Pro region of the SMV genome was degraded before the coat protein region. Transgenic soybean plants that expressed SMV HC-Pro showed dose-dependent alterations in unifoliate leaf morphologies and seed production where plants expressing the highest levels of HC-Pro had the most deformed leaves and the lowest seed production. Accumulation of microRNAs (miRNAs) and mRNAs putatively targeted by miRNAs was analyzed in leaves and flowers of healthy, HC-Pro-transgenic, and SMV-infected plants. Neither expression of SMV HC-Pro nor SMV infection produced greater than twofold changes in accumulation of six miRNAs. In contrast, SMV infection was associated with twofold or greater increases in the accumulation of four of seven miRNA-targeted mRNAs tested.