Transcriptome analysis of enriched Golovinomyces orontii haustoria by deep 454 pyrosequencing

Powdery mildews are phytopathogenic ascomycetes that have an obligate biotrophic lifestyle and establish intimate relationships with their plant hosts. A crucial aspect of this plant-fungus interaction is the formation of specialized fungal infection structures termed haustoria. Although located within the cell boundaries of plant epidermal cells, haustoria remain separated from the plant cytoplasm by a host plasma membrane derivative, the extrahaustorial membrane. Haustoria are thought to represent pivotal sites of nutrient uptake and effector protein delivery. We enriched haustorial complexes from Arabidopsis thaliana plants infected with the powdery mildew fungus Golovinomyces orontii and performed in-depth transcriptome analysis by 454-based pyrosequencing of haustorial cDNAs. We assembled 7077 expressed sequence tag (EST) contigs with greater than 5-fold average coverage and analyzed these with regard to the respective predicted protein functions. We found that transcripts coding for gene products with roles in protein turnover, detoxification of reactive oxygen species and fungal pathogenesis are abundant in the haustorial EST contigs, while surprisingly transcripts encoding presumptive nutrient transporters were not highly represented in the haustorial cDNA library. A substantial proportion (∼38%) of transcripts coding for predicted secreted proteins comprises effector candidates. Our data provide valuable insights into the transcriptome of the key infection structure of a model obligate biotrophic phytopathogen.

Sequential delivery of host-induced virulence effectors by appressoria and intracellular hyphae of the phytopathogen Colletotrichum higginsianum

Phytopathogens secrete effector proteins to manipulate their hosts for effective colonization. Hemibiotrophic fungi must maintain host viability during initial biotrophic growth and elicit host death for subsequent necrotrophic growth. To identify effectors mediating these opposing processes, we deeply sequenced the transcriptome of Colletotrichum higginsianum infecting Arabidopsis. Most effector genes are host-induced and expressed in consecutive waves associated with pathogenic transitions, indicating distinct effector suites are deployed at each stage. Using fluorescent protein tagging and transmission electron microscopy-immunogold labelling, we found effectors localised to stage-specific compartments at the host-pathogen interface. In particular, we show effectors are focally secreted from appressorial penetration pores before host invasion, revealing new levels of functional complexity for this fungal organ. Furthermore, we demonstrate that antagonistic effectors either induce or suppress plant cell death. Based on these results we conclude that hemibiotrophy in Colletotrichum is orchestrated through the coordinated expression of antagonistic effectors supporting either cell viability or cell death.

Biogenesis of a specialized plant-fungal interface during host cell internalization of Golovinomyces orontii haustoria

Powdery mildew fungi are biotrophic pathogens that require living plant cells for their growth and reproduction. Elaboration of a specialized cell called a haustorium is essential for their pathogenesis, providing a portal into host cells for nutrient uptake and delivery of virulence effectors. Haustoria are enveloped by a modified plant plasma membrane, the extrahaustorial membrane (EHM), and an extrahaustorial matrix (EHMx), across which molecular exchange must occur, but the origin and composition of this interfacial zone remains obscure. Here we present a method for isolating Golovinomyces orontii haustoria from Arabidopsis leaves and an ultrastructural characterization of the haustorial interface. Haustoria were progressively encased by deposits of plant cell wall polymers, delivered by secretory vesicles and multivesicular bodies (MVBs) that ultimately become entrapped within the encasement. The EHM and EHMx were not labelled by antibodies recognizing eight plant cell wall and plasma membrane antigens. However, plant resistance protein RPW8.2 was specifically recruited to the EHMs of mature haustoria. Fungal cell wall-associated molecular patterns such as chitin and β-1,3-glucans were exposed at the surface of haustoria. Fungal MVBs were abundant in haustoria and putative exosome vesicles were detected in the paramural space and EHMx, suggesting the existence of an exosome-mediated secretion pathway.

[Conventional reparation of parastomal hernia]

The reparation of parastomal hernias and their recurrence remain problematic although the implementation of mesh techniques has lowered recurrences rates. Conventional surgical techniques include suture repair, relocation of the stoma as well as diverse hernia repair procedures with mesh implantation. Suture repair has been abandoned due to its high recurrence rate. Simple relocation is not recommended because of high rates of recurrent parastomal hernias. Conventional hernia repair using mesh implants is classified according to the mesh position into epifascial (onlay), retromuscular (sublay) and intraperitoneal (IPOM) techniques. Furthermore, a combination of relocation with additional mesh enforcement is also possible. The value of the different mesh techniques and of new biological mesh prostheses must be evaluated in randomized controlled studies.

External iliac artery ligation due to late postoperative rupture after radical lymphadenectomy for advanced ovarian cancer--two case reports

According to the present guidelines for advanced epithelial ovarian cancer (EOC), bulky lymph nodes should be removed as part of the routine surgical staging and the primary goal being removal of all macroscopic tumor residuals. Furthermore, EOC-patients with bulky lymph node relapse seem to benefit from lymphadenectomy in terms of recurrence and overall survival.We present two cases of severe postoperative hemorrhage due to external iliac artery rupture ten and 12 days after radical bulky lymph node removal in primary and recurrent EOC-patients. Both cases were successfully managed by ligation of the two arms of the external iliac artery achieving immediate hemostasis. No crossover bypass was required to maintain lower extremity perfusion. Late rupture of the iliac vessels is a rare complication of systematic lymphadenectomy in EOC. This complication can be managed by unilateral external iliac artery ligation without mandatory subsequent graft interposition or crossover bypass.

Results of liver resection in combination with radiofrequency ablation for hepatic malignancies

INTRODUCTION

Liver tumors should be surgically treated whenever possible. In the case of bilobar disease or coexisting liver cirrhosis, surgical options are limited. Radiofrequency ablation (RFA) has been successfully used for irresectable liver tumors. The combination of hepatic resection and RFA extends the feasibility of open surgical procedures in patients with liver metastases and hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

RFA was performed with two different monopolar devices using ultrasound guidance. Intraoperative use of RFA for the treatment of liver metastases or HCC was limited to otherwise irresectable tumors during open surgical procedures including hepatic resections. Irresectability was considered if bilobar disease was treated, the functional hepatic reserve was impaired or appraised marginal for allowing further resection.

RESULTS

Ten patients with both liver metastases and HCC, and two patients with cholangiocellular carcinoma were treated. Complete initial tumor clearance was achieved in all patients. Two patients of the metastases group and five patients of the HCC group suffered from local recurrence after a median of 12 months (1-26) (local recurrence rate 32%). Five patients of the metastases group and six patients of the HCC group developed recurrent tumors in different areas of the ablation site after a median time of 4 months (2-18) (distant intrahepatic recurrence in 55%). Survival at 31 months was 36%.

CONCLUSION

RFA extends the scope of surgery in some candidates with intraoperatively found irresectability.

Do patients with recurrent ovarian cancer benefit from relative tumor reduction? Results from a prospective study

e16541

Background: Primary cytoreduction is the cornerstone in the management of epithelial ovarian cancer (OC). However, the roles of salvage surgery and of tumor reduction are still discussed controversially. The present study was conducted to assess the impact of secondary tumor reduction surgery on progression-free survival and on overall survival. Methods: Between September 2000 and April 2006, 177 consecutive patients (pts) with a first relapse of OC underwent secondary tumor reduction surgery at our department. The achieved tumor reduction was categorized as 1/5 (20% tumor debulked), 2/5 (40%), 3/5 (60%), 4/5 (80%), or 5/5 (macroscopic tumor-free) and the maximal tumor diameter was also denoted (tumor free, < 1cm, ≥ 1cm). Results: The median age was 56 years (95% CI: 23–83), median follow-up was 10.8 months (95% CI: 1–65). In 79 pts (44.6%) complete macroscopic tumor resection was achieved (median overall survival (OAS) 60.6 months, 21.3–99.8 and median progression-free survival (PFS) 14.9 months, 11.7–18, p < 0.001). In 56 pts (31.6%) 4/5 of the tumor was removed (OAS 15.6 months, 10.3–20.8 and PFS 9 months, 7.2–10.7, p < 0.001), in 13 (7.3%) 3/5 (OAS 21.7 months, no interval and PFS 12 months, 0.0–24.5, p < 0.001) and in 7 (4%) each 2/5 tumor reduction (OAS was 14.2 months, 4.1–24.2 and PFS 11 months, 5.9–16, p < 0.001) and if 1/5 tumor reduction was achieved OAS was 11.1 months, 2–20.1 and PFS 7 months, 2.5–11.4, p < 0.001. Fifteen pts (8.5%) had a bulky unresected disease (OAS 4.7 months, 1.0–8.3 and PFS of 3.7 months, 0–7.6, p < 0.001). From these 98 (55.4%) pts without complete macroscopic tumor resection, 46 were left with <1cm tumor diameter (OAS 17.2 months, 13–21.4 and PFS 9 months, 7.4–10.6 p < 0.001) and 52 with ≥1cm tumor diameter (OAS 8.7 months, 4.2–13.2 and PFS 7 months, 5.8–8.2 p < 0.001). All in all, the median postoperative survival for pts with tumor residuals and any tumor reduction (4/5, 3/5, 2/5. and 1/5 tumor reduction) were better when compared to pts with no tumor reduction (24.8 months vs. 4.7, p < 0.001). Conclusions: Our data demonstrate a significant benefit for salvage surgery if a macroscopic complete tumor resection can be achieved. We could not see any effect of relative tumor reduction on PFS or OAS.

No significant financial relationships to disclose.

Comparative analysis of the sialic acid binding activity and the tropism for the respiratory epithelium of four different strains of avian infectious bronchitis virus

Avian infectious bronchitis virus (IBV) is a major pathogen in commercial poultry flocks. We recently demonstrated that sialic acid serves as a receptor determinant for IBV on the tracheal epithelium. Here we compared the IBV strains Beaudette, 4/91, Italy02, and QX for their sialic acid-binding properties. We demonstrate that sialic acid binding is important for the infection of primary chicken kidney cells and the tracheal epithelium by all four strains. There were only slight differences between the four strains, indicating the universal usage of sialic acids as receptor determinants by IBV. In addition, we analysed the primary target cells in the respiratory epithelium of the four different strains and found that all of them infected ciliated cells and goblet cells.

Evaluation of bone strength, keel bone deformity and egg quality of laying hens housed in small group housing systems and furnished cages in comparison to an aviary housing system

Abstract. The objective of the study was to assess bone breaking strength, keel bone status and egg quality parameters of Lohmann Silver (LS) and Lohmann Tradition (LT) layers housed in small group systems (SG) and furnished cages (FC) in comparison to an aviary system. At the end of the 3rd, 6th, 9th and 11th laying month, approximately 40 hens were randomly chosen from each housing system and slaughtered (478 hens in total). Humerus and tibia strengths were analysed using a three-point-bending machine. Keel bone status was evaluated on a scale from 1 (severe) to 4 (no deformity). Shell breaking strength was measured every four weeks, totalling 4,887 eggs. Statistical analyses were performed using the MIXED procedure of SAS. Humerus and tibia strengths of LS layers housed in SG were significantly higher compared to LS hens kept in FC. Bone breaking strengths of humerus and tibia in LS and LT layers were highest in the aviary system and the differences to the other housing systems were significant. No significant differences in tibia and humerus bone breaking strengths were found between SG and FC for LT hens. Keel bone status was not significantly influenced by housing system or laying strain. For both hybrids, shell breaking strength was significantly lower in SG compared to FC and aviary system. The results showed that SG systems can significantly enhance bone breaking strength for LS layers in comparison to hens kept in FC. The lower shell breaking strength of eggs in SG might slightly impair economic aspects.

[New approaches to early detection, estimation of prognosis and therapy for malignant tumours of the gastrointestinal tract]

Tumours of the gastrointestinal tract are the single largest group of malignant tumours of humans accounting for approximately 2 million new cases and over 1.2 million deaths annually. They are most commonly a disease of the elderly, and their relative and absolute frequency will rise continuously due to an ageing population. This explains why the prevalence of gastric cancer increases in spite of a decreasing incidence. Gastrointestinal tumours will remain a major clinical and health economical challenge. The prognosis is often dismal. Most of these cancers are diagnosed in an advanced stage, which prohibits curative treatment and limits treatment options. In order to circumvent these problems, we need to develop strategies that allow identification of at-risk patients and tumours at an early stage, and raise the compliance in the general population for screening programmes. There is a great need in clinics for prognostic and predictive biomarkers that are able to tailor patient treatment at different stages of the disease.

[Composting of poultry carcasses as an alternative method for disposal in case of an outbreak of an epizootic disease: first results]

Composting of poultry carcasses represents an alternative method for disposal in case of an outbreak of an epizootic disease. Two composting experiments, each with a different construction of the compost pile, were carried out in a stable. In the first experiment two layers of turkey carcasses were formed. This compost pile covered with straw was directly built on the ground. In the second experiment no layers of carcasses were formed, and it was assembled on straw bales covered with plastic foil. One part of this compost pile was covered with straw, the other one was additionally covered with plastic foil. In the first experiment in the upper layers of the compost pile temperatures of up to 54.9 degrees C were reached and the decomposition of carcasses was very advanced with no soft tissues remaining after 30 days. In contrast temperatures of only 45.2 degrees C were reached in the lower layers and decomposition was far less advanced. This difference in decomposition was most likely caused by the temperature difference observed. In the second experiment the near complete decomposition seen in the upper layers of the compost pile at the first trial, was not achieved. Decomposition was more advanced in the straw covered part of this compost pile than in the part covered with straw and plastic foil. On the other hand, higher temperatures of up to 48.4 degrees C were measured in the lower layers of this compost pile most likely as a result of the increased heat insulation in particular to the ground.

Surgical techniques for resectable pancreatic cancer

Pancreatic cancer is a highly aggressive cancer with a rising incidence in most European countries. Due to both the aggressive biology of the disease and the late diagnosis in many cases, pancreatic duct carcinoma is still a disease with a poor prognosis. Today, surgical resection of localized tumor remains the only potentially curative option available for these patients. Advances in surgical techniques and perioperative care has improved significantly in the last 20 years, causing an extension of indications for surgical intervention. However, despite new diagnostic techniques, the surgical exploration still plays the key role for the finally assessment of resectability. For evaluation of local resectability, laparoscopy alone cannot generally be recommended today and explorative laparotomy is required. Contraindications for pancreatic resection are liver metastasis, peritoneal metastasis, and tumor infiltration of visceral arteries. The surgical management of pancreatic cancer consists of two phases: first, assessment of tumor resectability and second, if resectability is given, the pancreaticoduodenectomy with consecutive reconstruction. Standard surgical strategies are the classic pancreaticoduodenectomy including a distal gastrectomy and the pylorus-preserving pancreaticoduodenectomy (PPPD) preserving antral and pyloric function, respectively. Both surgical procedures are equally effective for the treatment of pancreatic carcinoma. Delicate lymphadenectomy during pancreaticoduodenectomy is important for radical oncological enforcement. An extended lymphadenectomy showed no benefit in several trials. Despite the encouraging advances in surgical treatment, actuarial 5-year survival rates after pancreatic resection are only at about 20%.

Liver resection for metastases from renal cell carcinoma

BACKGROUND

This study was conducted to evaluate the safety and efficacy of liver resection in patients with hepatic metastases from renal cell carcinoma and to identify selection criteria for patients suitable for resection.

METHODS

Between January 1988 and March 2006, 31 patients underwent liver resection for metastases from renal cell carcinoma. Patients were identified from a prospective database and retrospectively reviewed. Patient, tumor, and operative parameters were analyzed for their influence on long-term survival.

RESULTS

The overall 1-, 3- and 5-year survival rates were 82.2%, 54.3%, and 38.9%, respectively. One patient was deceased and 4 developed complications during the postoperative course. In the univariate analysis, site of the primary tumor (P = 0.013), disease-free interval (P = 0.012), and resection margins (P = 0.008) showed significant influence on long-term survival. In the multivariate analysis, only the resection margins were identified as an independent prognostic factor after liver resection.

CONCLUSIONS

Liver resection is effective and safe in the treatment of patients with hepatic metastases from renal cell carcinoma and offers the chance of long-term survival and cure. Achieving a margin-negative resection is the most important criterion in the selection of suitable patients for liver resection. However, the number of patients in the present study was small, and investigations of larger series may provide further prognostic parameters in these patients.