Vitis Methods to Understand and Develop Strategies for Diagnosis and Sustainable Control of Grapevine Trunk Diseases

Vitis vinifera is affected by many diseases every year, depending on causal agents, susceptibility of cultivars, and climate region. Some are caused by a single agent, such as gray mold caused by Botrytis cinerea or powdery mildew caused by Erysiphe necator. Others result from the actions of a complex of pathogens such as grapevine trunk diseases (GTDs). GTDs are presently among the most devastating diseases in viticulture worldwide because both the economic losses and the long-term sustainability of vineyards are strongly affected. The complexity of GTDs results from the diversity of associated fungi, the undetermined period of latency within the vine (asymptomatic status), the erratic foliar symptom expression from one year to the next, and, probably correlated with all of these points, the lack of efficient strategies to control them. Distinct methods can be beneficial to improve our knowledge of GTDs. In vitro bioassays with cell suspensions, calli, foliar discs, full leaves, or plantlets, and in vivo natural bioassays with cuttings, grafted plants in the greenhouse, or artificially infected ones in the vineyard, can be applied by using progressive integrative levels of in vitro and in vivo, depending on the information searched. In this review, the methods available to understand GTDs are described in terms of experimental procedures, main obtained results, and deliverable prospects. The advantages and disadvantages of each model are also discussed.

Secreted proteins produced by fungi associated with Botryosphaeria dieback trigger distinct defense responses in Vitis vinifera and Vitis rupestris cells

Grapevine trunk diseases (Eutypa dieback, esca and Botryosphaeria dieback) are caused by a complex of xylem-inhabiting fungi, which severely reduce yields in vineyards. Botryosphaeria dieback is associated with Botryosphaeriaceae. In order to develop effective strategies against Botryosphaeria dieback, we investigated the molecular basis of grapevine interactions with a virulent species, Neofusicoccum parvum, and a weak pathogen, Diplodia seriata. We investigated defenses induced by purified secreted fungal proteins within suspension cells of Vitis (Vitis rupestris and Vitis vinifera cv. Gewurztraminer) with putative different susceptibility to Botryosphaeria dieback. Our results show that Vitis cells are able to detect secreted proteins produced by Botryosphaeriaceae, resulting in a rapid alkalinization of the extracellular medium and the production of reactive oxygen species. Concerning early defense responses, N. parvum proteins induced a more intense response compared to D. seriata. Early and late defense responses, i.e., extracellular medium alkalinization, cell death, and expression of PR defense genes were stronger in V. rupestris compared to V. vinifera, except for stilbene production. Secreted Botryosphaeriaceae proteins triggered a high accumulation of δ-viniferin in V. vinifera suspension cells. Artificial inoculation assays on detached canes with N. parvum and D. seriata showed that the development of necrosis is reduced in V. rupestris compared to V. vinifera cv. Gewurztraminer. This may be related to a more efficient induction of defense responses in V. rupestris, although not sufficient to completely inhibit fungal colonization. Overall, our work shows a specific signature of defense responses depending on the grapevine genotype and the fungal species.

Phytotoxic metabolites from Neofusicoccum parvum, a pathogen of Botryosphaeria dieback of grapevine

Liquid chromatography-diode array screening of the organic extract of the cultures of 13 isolates of the fungus Neofusicoccum parvum, the main causal agent of botryosphaeria dieback of grapevine, showed similar metabolites. One strain was selected for further chemical studies and led to the isolation and characterisation of 13 metabolites. Structures were elucidated through spectroscopic analyses, including one- and two-dimensional NMR and mass spectrometry, and through comparison to literature data. The isolated compounds belong to four different chemical families: five metabolites, namely, (-)-terremutin (1), (+)-terremutin hydrate (2), (+)-epi-sphaeropsidone (3) (-)-4-chloro-terremutin hydrate (4) and(+)-4-hydroxysuccinate-terremutin hydrate (5), belong to the family of dihydrotoluquinones; two metabolites, namely, (6S,7R) asperlin (6) and (6R,7S)-dia-asperlin (7), belong to the family of epoxylactones; four metabolites, namely, (R)-(-)-mellein (8), (3R,4R)-4-hydroxymellein (9), (3R,4S)-4-hydroxymellein (10) (R)(-)-3-hydroxymellein (11), belong to the family of dihydroisocoumarins; and two of the metabolites, namely, 6-methyl-salicylic acid (12) and 2-hydroxypropyl salicylic acid (13), belong to the family of hydroxybenzoic acids. We determined the phytotoxic activity of the isolated metabolites through a leaf disc assay and the expression of defence-related genes in Vitis vinifera cells cv. Chardonnay cultured with (-)-terremutin (1), the most abundant metabolite. Finally, analysis of the brown stripes of grapevine wood from plants showing botryosphaeria dieback symptoms revealed the presence of two of the isolated phytotoxins.

Toxicity of extracellular proteins from Diplodia seriata and Neofusicoccum parvum involved in grapevine Botryosphaeria dieback

Botryosphaeria dieback, esca and Eutypa dieback are three economic major grapevine trunk diseases that cause severe yield reduction in vineyards worldwide. The frequency of disease symptoms has increased considerably over the past decade, and no efficient treatment is currently available to control these diseases. The different fungi associated with grapevine trunk diseases mainly induce necrotic wood and characteristic foliar symptoms. In this context, fungi virulence factors and host invasion are not well understood. We hypothesise that extracellular proteins produced by Diplodia seriata and Neofusicoccum parvum, two causal agents associated with Botryosphaeria dieback, are virulence factors responsible for the pathogenicity. In our previous work, we demonstrated that the total extracellular compounds produced by N. parvum induced more necrosis on Chardonnay calli and triggered a different defence gene expression pattern than those produced by D. seriata. Furthermore, this aggressiveness was not clearly correlated with the production of mellein, a characteristic phytotoxin of Botryosphaeriaceae, in our in vitro calli model. To characterise other potential virulence factors and to understand the mechanisms of host invasion by the fungus, we evaluated the profile, quantity and the impact of extracellular proteins produced by these fungi on Vitis vinifera calli necrosis and defence gene expression. Our results reveal that, under the same conditions, N. parvum produces more extracellular proteins and in higher concentrations than D. seriata. With Vitis vinifera cv. Chardonnay cells, we showed that equivalent concentrations of proteins secreted by N. parvum were more aggressive than those of D. seriata in producing necrosis and that they clearly induced more grapevine defence genes.

Extracellular compounds produced by fungi associated with Botryosphaeria dieback induce differential defence gene expression patterns and necrosis in Vitis vinifera cv. Chardonnay cells

Three major grapevine trunk diseases, esca, botryosphaeria dieback and eutypa dieback, pose important economic problems for vineyards worldwide, and currently, no efficient treatment is available to control these diseases. The different fungi associated with grapevine trunk diseases can be isolated in the necrotic wood, but not in the symptomatic leaves. Other factors seem to be responsible for the foliar symptoms and may represent the link between wood and foliar symptoms. One hypothesis is that the extracellular compounds produced by the fungi associated with grapevine trunk diseases are responsible for pathogenicity.In the present work, we used Vitis vinifera cv. Chardonnay cells to test the aggressiveness of total extracellular compounds produced by Diplodia seriata and Neofusicoccum parvum, two causal agents associated with botryosphaeria dieback. Additionally, the toxicity of purified mellein, a characteristic toxin present in the extracellular compounds of Botryosphaeriaceae, was assessed.Our results show that the total extracellular compounds produced by N. parvum induce more necrosis on Chardonnay calli and induce a different defence gene expression pattern than those of D. seriata. Mellein was produced by both fungi in amounts proportional to its aggressiveness. However, when purified mellein was added to the culture medium of calli, only a delayed necrosis and a lower-level expression of defence genes were observed. Extracellular compounds seem to be involved in the pathogenicity of the fungi associated with botryosphaeria dieback. However, the doses of mellein used in this study are 100 times higher than those found in the liquid fungal cultures: therefore, the possible function of this toxin is discussed.

[Early clinical outcome after navigated total knee arthroplasty. Comparison with conventional implantation in TKA: a controlled and prospective analysis]

BACKGROUND

Navigated implantation of total knee prostheses has become more and more popular within the last decade in orthopaedic surgery. Although improved alignment after navigated knee surgery has been reported previously in the literature, only a few studies meet the criteria of a level-1 evidence-based medicine study. We present the results of a controlled and prospective study comparing early clinical outcomes after computer-assisted versus conventional implantation in total knee arthroplasty (TKA).

METHODS

Within a 15-month period, all patients admitted for primary TKA were followed prospectively. Each patient was evaluated using the Knee Society Score (KSS) preoperatively, 10 days after surgery, and 3 months after surgery. The patients were divided into two groups, and the implantation technique altered between the two treatment options: each conventional implantation was strictly followed by a computer-assisted procedure and vice versa.

RESULTS

From March 2003 to June 2004, we did 34 computer-assisted (group A) and 35 conventional knee arthroplasties (group B) in 62 patients. There was no difference in the preoperative status of the patients. Surgeries in group A took significantly longer than in group B. The average deviation from correct alignment was significantly reduced in group A. 66 of 69 of the TKAs were available for follow-up examinations after 10 days and after 3 months. No significant differences were found in the overall KSS scores or in the subgroups.

CONCLUSIONS

The intraoperative use of a computer-assisted navigation system during implantation of a total knee prosthesis reduced the average varus/valgus deviation from the anatomical long leg axis. A disadvantage of the computer-assisted surgical procedure may be the longer operating time. Long-term follow-up of the presented data is needed in order to show whether the improved average alignment is advantageous for patients and/or results in a longer service life of the TKA.

Regression and correlation analysis of preoperative versus intraoperative assessment of axes during navigated total knee arthroplasty

OBJECTIVE

Modern computer assisted surgery (CAS) systems allow accurate positioning of the implants in navigated Total Knee Arthroplasty (TKA). However, when an operation is performed with a navigation system, it is important to know if the anatomical situation of the knee is reflected equally in both the preoperative image (e.g., CT) and the intraoperative navigation setup. In this study, we compared the preoperative anatomical situation to the virtual intraoperative situation of the navigation setup.

MATERIAL AND METHODS

We analyzed 24 navigated operations. Intraoperatively, the condylar twist angle (CTA) was documented with the navigation system by measuring the angle between the transepicondylar axis (TEA) and posterior condyle axis (PCA). This data was compared with the preoperative data from the CT scan.

RESULTS

Statistical analysis revealed that there was no correlation between the pre- and intraoperative data (r = 0.095).

CONCLUSIONS

Statistically, there is no possibility of collecting the same angles and axes when using the two different methods (CT and navigation) on the same knee. It is not possible to copy the preoperative anatomical situation exactly with the virtual intraoperative data. Reasons for this include systematic errors, as well as inter- and intraobserver errors in both methods.

[CT analysis of leg alignment after conventional vs. navigated knee prosthesis implantation. Initial results of a controlled, prospective and randomized study]

INTRODUCTION

Correct alignment of the leg is one of the significant factors for the outcome after TKA. Previous studies have shown that the use of a navigation system can improve the alignment. However, for the positioning of the femoral component no validated data are available. This article presents the first results of a controlled, prospective and randomised trial comparing navigation versus free-hand implantation in TKA with special reference to the rotation of the femoral component.

METHODS

Since January 2003, all patients with primary arthrosis of the knee admitted to our hospital for TKA have been followed prospectively. For this first analysis, data were collected over a period of 5 months. Apart from the usual clinical evaluations, all patients had CT of the leg prior to the operation and 1 week postoperatively. Measurement of axis and rotation was performed by staff members of the X-ray department who had no knowledge of the operation technique (navigation vs. free-hand).

RESULTS

Twenty five sets of CT scans have been analysed, from 12 navigated operations and 13 freehand procedures. All 12 of the navigated knees were within the interval of +/-3 degrees varus/valgus deviation, but only 8 of the 13 non-navigated knees met this criteria. The analysis of the rotation position of the femoral component revealed no difference between the two groups.

CONCLUSION

By using an intraoperative navigation system, the accuracy of the alignment in TKA can be improved. Long-term studies will have to be carried out to verify whether this will lead to a lasting benefit for the patient. Concerning the rotation position of the femoral implant, no conclusion can be made regarding the recommended rotation position at this point of the study.

Reconstruction of the lateral ligaments: do the anatomical procedures restore physiologic ankle kinematics?

BACKGROUND

If conservative therapy fails, the standard treatment for chronic ankle instability is surgical reconstruction of the lateral ligaments. For the last seventy years, the tenodesis principles have been used for reconstruction. Recently however, surgical reconstructions--respecting the intact joint anatomy--have been developed, thus called "anatomical reconstruction principles".

METHODS

This study focused on the investigation of the range of motion of the ankle and the subtalar joint following anatomical reconstruction surgery. Three different types of anatomical reconstruction procedures were compared: Direct ligament repair, tendon graft and carbon-fiber implant.

RESULTS

All procedures restored the original range of motion of the subtalar joint, except for the plantarflexed/dorsiflexed positions. As for the talocrural joint, the tendon graft and the carbon fiber implant left a small laxity for movements of inversion/eversion and internal/external rotation. The direct repair procedure achieved a more accurate result and restored the physiologic kinematics almost completely. During each procedure the insertion points and the direction of the original ligaments were maintained. However, the different results for the procedure of direct ligament repair compared to the other two anatomical reconstruction procedures showed that this condition alone is not sufficient to perfectly restore the kinematics of the talocrural and subtalar joints. It is important to note that none of the procedures caused a restriction of the range of motion.

CONCLUSIONS

The maintenance of the range of hindfoot motion decreases the risk of osteoarthritis as well as chronic pain or problems for the patient to walk on uneven surface. Therefore, we believe that standard therapy for chronic instability of the ankle should include direct surgical reconstruction of the ligaments. If this direct procedure cannot be performed because of poor quality of the ligaments an alternative anatomical reconstruction procedure should be considered.

Properties of a chimeric simian-human immunodeficiency virus expressing an hybrid HIV-1 Nef/SIVmac Nef protein

The nef genes of human and simian immunodeficiency viruses code for a membrane associated protein critical for AIDS development. SIVmac Nef presents C-terminal a 27 amino acid extension absent of HIV-1 Nef. To estimate the influence of this C-terminal domain on virus properties, we constructed viruses derived from SIVmac239 by replacing SIV nef with HIV-1 Lai nef gene (SHIV NefLai4) or with a sequence encoding a Nef fusion protein: HIV-1 Lai Nef/SIV Nef-Cterm (SHIV-Cterm). The recombinant viruses replicated efficiently in vitro in CEMx174 cells and in activated macaque PBMCs. The addition of SIV Nef C-terminal domain to HIV-1 Nef in SHIVNefLai4 did not change the in vitro properties of the chimeric virus, both viruses being more infectious than a nef deleted virus. Although the half-life of Nef fusion protein was augmented, SHIV-Cterm remained slightly less infectious than SIVmac239.

Revision hip arthroplasty in a patient with a hip rotationplasty (type B III b)

We report for the first time a patient who underwent a revision hip arthroplasty after a hip rotationplasty (Winkelmann type B III b) because of a chondrosarcoma in 1988. The clinical symptoms and radiographic findings (X-ray, bone scintigraphy, arthrography) of the aseptic loosening of the acetabular component are presented in detail. Furthermore, we present the functional results after hip revision.

[Intra-articular and plantar pressure distribution of the ankle joint complex in relation to foot position]

Ankle injuries are often followed by degenerative changes in the hindfoot joints. Knowledge about the pressure distribution of the intact ankle joint may help to understand the mechanisms leading to cartilage damage. Therefore, we determined the intraarticular and plantar pressure distribution of the ankle joint complex and the Chopart joints with varying foot positions. 12 human lower leg specimens were axially loaded in a foot-loading simulator with full body weight (600 N). A capacitive pressure distribution platform was used to determine plantar pressure patterns. The intraarticular loading situation was measured with Fuji Prescale film. 3 different foot positions (neutral, 10 degrees dorsiflexion, 10 degrees plantarflexion) were investigated. Dorsiflexion led to an increase of the intraarticular contact area, force and mean pressure in the hindfoot. Plantarflexion instead increased loading in the Chopart joints. In the plantar pressure distribution force and peak pressure under the hindfoot increased with dorsiflexion. With plantarflexion area, force and peak pressure under mid- and forefoot increased. With our study we could demonstrate that the loading situation of the ankle joint complex is significantly influenced by the foot position. These findings may help to understand the development and localisation of arthritic changes due to posttraumatic changes of the joint loading characteristics.

NOVEL Award 1996: 2nd prize Tenodeses do not fully restore ankle joint loading characteristics: a biomechanical in vitro investigation in the hind foot

OBJECTIVE: In order to understand the biomechanical consequences of ligament injuries and surgical reconstruction procedures, their effects on intra-articular loading in the ankle joint complex and Chopart joint line and on the plantar pressure patterns were investigated in vitro. METHODS: Twelve fresh-frozen lower leg specimens were freed of soft tissue down to the malleoli and prepared for accessing the talocrural, subtalar, talonavicular and calcaneocuboid joints. The specimens were fixed in a loading simulator and axially loaded with 600 N in six experimental conditions: intact; after cutting the anterior talofibular ligament; after additionally cutting the calcaneofibular ligament; after performing three common types of tenodeses, the Evans, Watson-Jones and Chrisman-Snook procedures. The intra-articular loading characteristics were determined with pressure sensitive film. Plantar loading patterns were measured with a capacitive EMED pressure distribution platform. RESULTS: Average intra-articular pressures were increased and were related either to decreased contact areas or to increased contact forces found in all joints after ligament resections and tenodeses. Plantar loading was increased under the medial aspect of the foot and decreased under the midfoot region. CONCLUSIONS: The results indicate that ankle ligament injuries, as well as surgical reconstructions by tenodeses, affect joint loading characteristics and may exacerbate joint degeneration. RELEVANCE: Excessive laxity of the ankle joint is considered a pre-arthrotic condition and is treated with various surgical procedures. Some of these procedures that utilize the tendon of the peroneus brevis have been shown to change joint kinematics. The aim was to evaluate joint loading characteristics and the potential danger of developing arthritis as a consequence of various tenodeses techniques. For this purpose, in vitro investigations are needed to directly determine intra-articular pressure measurements.

[Foot stress simulator for biomechanical in vitro studies of lower leg segments]

In this paper we describe a foot-loading simulator that permits in vitro studies on human lower leg and foot specimens. The specimens are fixed in a jig and loaded axially with the aid of a pneumatic cylinder. The resulting transfer of forces through the ankle joint complex and Chopart's articulation (line) can be demonstrated on a pressure-sensitive film. Plantar pressure measurements obtained in patients or normal subjects can be used to ensure the comparability of in vivo and in vitro measurements. The supporting platform can be tilted in such a manner as to provide a range of foot positions up to 20 degrees in plantar- or dorsiflexion, eversion or inversion. The system is used for investigating the effects on the intra-articular pressures and plantar pressure patterns of physiological muscle activity and pathological conditions following fracture of the calcaneum or damage to the lateral ligament. By way of an example, the effects of muscle forces on plantar pressure distribution are presented.

CREST syndrome: a variant of systemic sclerosis

A variant of systemic sclerosis (scleroderma), CREST syndrome affects a relatively small number of patients. CREST (also called limited cutaneous scleroderma) has a more favorable prognosis than the diffuse form of scleroderma. However, as with most of the connective tissue diseases, the daily issues faced by patients are frequently difficult to manage and require diligent support from the health care team. This article summarizes the clinical manifestations and potential management plan to help the patient cope with this little-understood syndrome. The nursing care model follows a problem-oriented approach for nursing management.