Molecular detection of Fusarium solani f. sp. glycines in soybean roots and soil   总被引：5，自引：0，他引：5  

S. Li †  G. L. Hartman 《Plant pathology》2003,52(1):74-83

A polymerase chain reaction (PCR)-based method was developed to detect DNA of Fusarium solani f. sp. glycines , the cause of soybean sudden death syndrome. Two pairs of primers, Fsg1/Fsg2 designed from the mitochondrial small subunit ribosomal RNA gene, and FsgEF1/FsgEF2 designed from the translation elongation factor 1-α gene, produced PCR products of 438 and 237 bp, respectively. Primer specificity was tested with DNA from 82 F. solani f. sp. glycines , 55 F. solani non-SDS isolates, 43 isolates of 17 soybean fungal pathogens and the oomycete Phytophthora sojae , and soybean. The sensitivity of primer Fsg1/Fsg2 was 10 pg while that of FsgEF1/FsgEF2 was 1 ng when using F. solani f. sp. glycines total genomic DNA or down to 10³ macroconidia g⁻¹ soil. Nested PCR increased the sensitivity of the PCR assay 1000-fold to 10 fg using primers Fsg1/Fsg2, and 1 pg using primers FsgEF1/FsgEF2. F. solani f. sp. glycines DNA was detected in field-grown soybean roots and soil by PCR using either single pairs of primers or the combination of two pairs of primers. The occurrence of F. solani f. sp. glycines was determined using nested PCR for 47 soil samples collected from soybean fields in 20 counties of Illinois in 1999. F. solani f. sp. glycines was detected in soil samples from all five Illinois Agricultural Statistic Districts including 100, 89, 50, 92 and 50% of the samples from East, Central, North-east and West Districts, respectively.  相似文献   

Evaluation of the rostral projection of the sacral lamina as a component of degenerative lumbosacral stenosis in German shepherd dogs          下载免费PDF全文

Harvey Saunders BVSc  Andrew J. Worth BVSc  PhD  FANZCVS  Janis P. Bridges BSc  GradDip Appl Stat  Angela Hartman DVM  DipACVR 《Veterinary surgery : VS》2018,47(5):654-663

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Death of a neonatal lamb due to Clostridium perfringens type B in New Zealand     

JS Munday  H Bentall  D Aberdein  M Navarro  FA Uzal  S Brown 《New Zealand veterinary journal》2020,68(4):242-246

ABSTRACT

Case history and clinical findings: A flock of 20 sheep was kept within three paddocks on a single property. None of the animals in the flock had been vaccinated against any disease for at least three years. Abdominal bloating and haemorrhagic diarrhoea were observed in Lamb 1 at 24 hours-of-age. The lamb subsequently died within an hour of the onset of clinical signs. Lamb 2 was 3-days-old when observed to be recumbent with opisthotonus. The lamb was treated with dextrose, vitamins B1 and B12, and penicillin G, but died 4 hours later.

Pathological findings: Examination of Lamb 1 revealed markedly increased gas within the peritoneum and within dilated loops of intestine. The intestines were dark red and contained large quantities of haemorrhagic fluid. Histology of the intestines revealed peracute mucosal necrosis with minimal accompanying inflammation. The intestinal lumen contained cell debris, haemorrhage, and myriad large Gram-positive bacilli. The intestines of Lamb 2 did not appear bloated or reddened. However, multiple fibrin clots were visible within the pericardial sac. Histopathological examination revealed small foci of necrosis within the mucosa of the distal intestine. The necrotic foci were often associated with large numbers of large Gram-positive bacilli.

Immunohistochemsitry and molecular biology: Intestinal samples from Lamb 1 were processed for Clostridium perfringens immunohistochemistry, which revealed large numbers of intralesional, positively immunostained rods. Fragments corresponding to the expected sizes for genes encoding alpha, beta, and epsilon C. perfringens typing toxins were amplified by PCR from DNA extracted from formalin-fixed sections of intestine.

Diagnosis: Lamb dysentery due to C. perfringens type B.

Clinical relevance: C. perfringens bacteria have a worldwide distribution, but disease due to C. perfringens type B has only been diagnosed in a small number of countries and has never been reported in New Zealand or Australia. C. perfringens type B produce both beta toxin and epsilon toxins, therefore both haemorrhagic enteritis and systemic vascular damage can develop. As many animals are exposed to C. perfringens without developing disease, there must be additional unknown factors that resulted in disease in these particular sheep. Vaccines that specifically protect against C. perfringens type B are available and may be recommended for use in smaller non-commercial flocks, as in the present case.  相似文献   

Carbon Depletion by Plowing and its Restoration by No‐Till Cropping Systems in Oxisols of Subtropical and Tropical Agro‐Ecoregions in Brazil     

Joo Carlos de Moraes S  Lucien Sguy  Florent Tivet  Rattan Lal  Serge Bouzinac  Paulo Rogrio Borszowskei  Clever Briedis  Josiane Burkner dos Santos  Daiani da Cruz Hartman  Clayton Giani Bertoloni  Jadir Rosa  Theodor Friedrich 《Land Degradation \u0026amp; Development》2015,26(6):531-543

The continuous use of plowing for grain production has been the principal cause of soil degradation. This project was formulated on the hypothesis that the intensification of cropping systems by increasing biomass‐C input and its biodiversity under no‐till (NT) drives soil restoration of degraded agro‐ecosystem. The present study conducted at subtropical [Ponta Grossa (PG) site] and tropical regions [Lucas do Rio Verde, MT (LRV) site] in Brazil aimed to (i) assess the impact of the continuous plow‐based conventional tillage (CT) on soil organic carbon (SOC) stock vis‐à‐vis native vegetation (NV) as baseline; (ii) compare SOC balance among CT, NT cropping systems, and NV; and (iii) evaluate the redistribution of SOC stock in soil profile in relation to soil resilience. The continuous CT decreased the SOC stock by 0·58 and 0·67 Mg C ha⁻¹ y⁻¹ in the 0‐ to 20‐cm depth at the PG and LRV sites, respectively, and the rate of SOC sequestration was 0·59 for the PG site and ranged from 0·48 to 1·30 Mg C ha⁻¹ y⁻¹ for the LRV site. The fraction of C input by crop residues converted into SOC stock was ~14·2% at the PG site and ~20·5% at the LRV site. The SOC resilience index ranged from 0·29 to 0·79, and it increased with the increase in the C input among the NT systems and the SOC sequestration rates at the LRV site. These data support the hypothesis that NT cropping systems with high C input have a large potential to reverse the process of soil degradation and SOC decline. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

种间关系对中条山油松人工林天然更新及群落稳定性的影响          下载免费PDF全文

裴顺祥  法蕾  杜满义  郭嘉  辛学兵 《林业科学研究》2022,35(1):150-157

[目的]为了揭示种间关系对中条山油松人工林天然更新及群落稳定性的影响,为油松人工林经营管理提供理论依据.[方法]基于中条山油松人工林群落样地调查数据,分析油松人工林下主要植物的种间关联性、生态位重叠及群落稳定性,并在此基础上探讨种间关联和生态位理论在油松人工林天然更新障碍及群落稳定性形成机制中的作用.[结果]中条山油松...  相似文献   

Effect of preculture freezing and incubation on bacteriological isolation from subclinical mastitis samples     

Sol J  Sampimon OC  Hartman E  Barkema HW 《Veterinary microbiology》2002,85(3):241-249

In this study the sensitivity of three methods of isolation of udder pathogens from milk samples from subclinical mastitis cases was compared. For analysis 1827 quarter milk samples were selected. Milk was cultured using a standard culture technique (0.01 ml of fresh milk streaked on a sheep blood agar plate and on Edward's medium). In addition, an inoculum of 0.01 ml of the original milk sample was incubated for 24h at 37 degrees C in broth, followed by culture using the standard culture technique. In the third method, the whole milk sample was frozen for 24h, and then incubated for 24h at 37 degrees C, followed by culture using standard culture technique. The isolation percentage of Staphylococcus aureus was 4.7% for standard culture technique, 14.2% for incubation in broth, and 21.5% for the combination of freezing plus incubation. Isolation percentage of Streptococcus dysgalactiae and Streptococcus agalactiae was highest using the standard culture technique, while isolation rate of Streptococcus uberis was not different among the three methods used. With increasing somatic cell count, the likelihood of S. aureus, S. dysgalactiae and S. uberis isolation increased.Based on the relative sensitivity, defined as the isolation rate using a single technique compared to the isolation rate of the three techniques together, a combination of standard culture technique and freezing plus incubation was most attractive for achieving a high isolation rate of S. agalactiae and S. dysgalactiae. Relative sensitivity of S. uberis isolation was highest using the standard culture technique and incubation in broth, while S. aureus was most often isolated using a combination of incubation in broth and freezing plus incubation. A combination of the three methods increased the isolation rate for S. dysgalactiae, S. uberis and S. aureus. The standard culture technique, together with the combination of freezing plus incubation, can be recommended for isolating major udder pathogens. If S. aureus is the pathogen of main interest, using incubation in broth together with the combination of freezing plus incubation performed best.  相似文献   

Molecular Identification and Phylogenetic Grouping of Diaporthe phaseolorum and Phomopsis longicolla Isolates from Soybean     

Zhang AW  Riccioni L  Pedersen WL  Kollipara KP  Hartman GL 《Phytopathology》1998,88(12):1306-1314

ABSTRACT Diaporthe phaseolorum and Phomopsis longicolla isolates from soybean were examined using traditional mycological characteristics and molecular methods. Cultural characteristics including types of fruiting bodies and conidia were assessed for isolates collected from soybean stems and seeds. Cultures were identified as P. longicolla, D. phaseolorum var. caulivora, D. phaseolorum var. meridionalis, or D. phaseolorum var. sojae. Molecular markers for these groups were developed and analyzed using polymerase chain reaction restriction fragment length polymorphisms (PCR-RFLP) and DNA sequencing in the internal transcribed spacer (ITS) and the 5.8S ribosomal DNA. The ITS(4) and ITS(5) primers amplified PCR products for all isolates studied. Gel electrophoresis of undigested PCR products and DNA sequencing produced various fragment lengths including 604 bp for P. longicolla, 602 and 603 bp for D. phaseolorum var. caulivora, 603 bp for D. phaseolorum var. meridionalis, and from 597 to 609 bp for D. phaseolorum var. sojae. Digestion of these PCR products with enzymes AluI, HhaI, MseI, RsaI, and ScrFI resulted in distinct bands for identification of P. longicolla and the varieties of D. phaseolorum I. All P. longicolla, D. phaseolorum var. caulivora, and D. phaseolorum var. meridionalis isolates were distinguished using AluI and HhaI with RsaI or ScrFI. The banding patterns of D. phaseolorum var. sojae isolates were complex and were separated into 11 subgroups after digestion with AluI, HhaI, MseI, RsaI, and ScrFI. Phylogenetic analysis of 20 isolates of D. phaseolorum and P. longicolla based on the DNA sequence of the ITS region resolved six clades termed A, B, C, D, E, and F. Clade A included all sequenced D. phaseolorum var. caulivora isolates, two from Italy and one from the United States. Isolates in clade B were exclusively associated with D. phaseolorum var. meridionalis. Clades A and B formed a well-supported monophyletic group. Isolates in clades C, D, E, and F were morphologically defined as isolates of P. longicolla, D. phaseolorum var. sojae, and Diaporthe spp. The ITS sequences similarity of seven geographically diverse P. longi-colla isolates illustrated that P. longicolla isolates have a similar genetic background, with some affiliations to some D. phaseolorum var. sojae isolates. Morphological characteristics of the isolates along with the terminal clades of the ITS phylogeny suggest that P. longicolla is an individual species, D. phaseolorum var. caulivora and D. phaseolorum var. meridionalis are varieties of D. phaseolorum, and D. phaseolorum var. sojae is either several varieties of D. phaseolorum or possibly several distinct species.  相似文献   

国有苗圃所有制结构调整之我见     

周国平  李发凯 《江西林业科技》2001,(Z1)

所有制结构的调整是国有苗圃发展壮大的出路所在.笔者从必要性,战略方向,基本途径等三个方面阐述了看法.  相似文献   

3种阔叶树育苗技术及苗木生长规律研究初探   总被引：2，自引：0，他引：2  

刘志强  肖水清  邹元熹  肖才发 《江西林业科技》2001,(3):14-15

通过对闽楠，蓝果树，东京野茉莉的育苗试验，研究苗木生长规律，掌握生理生物学特性。  相似文献   

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

Lim HS  Ko TS  Hobbs HA  Lambert KN  Yu JM  McCoppin NK  Korban SS  Hartman GL  Domier LL 《Phytopathology》2007,97(3):366-372

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.  相似文献