A toolbox to analyze collective cell migration, proliferation and cellular organization simultaneously

BACKGROUND

Analyses of collective cell migration and orientation phenomena are needed to assess the behavior of multicellular clusters. While some tools to the authors' knowledge none is capable to analyze collective migration, cellular orientation and proliferation in phase contrast images simultaneously.

METHODS

We provide a tool based to analyze phase contrast images of dense cell layers. PIV is used to calculatevelocity fields, while the structure tensor provides cellular orientation. An artificial neural network is used to identify cell division events, allowing to correlate migratory and organizational phenomena with cell density.

CONCLUSION

The presented tool allows the simultaneous analysis of collective cell behavior from phase contrast images in terms of migration, (self-)organization and proliferation.

Elucidation of GPR55-Associated Signaling behind THC and LPI Reducing Effects on Ki67-Immunoreactive Nuclei in Patient-Derived Glioblastoma Cells

GPR55 is involved in many physiological and pathological processes. In cancer, GPR55 has been described to show accelerating and decelerating effects in tumor progression resulting from distinct intracellular signaling pathways. GPR55 becomes activated by LPI and various plant-derived, endogenous, and synthetic cannabinoids. Cannabinoids such as THC exerted antitumor effects by inhibiting tumor cell proliferation or inducing apoptosis. Besides its effects through CB1 and CB2 receptors, THC modulates cellular responses among others via GPR55. Previously, we reported a reduction in Ki67-immunoreactive nuclei of human glioblastoma cells after GPR55 activation in general by THC and in particular by LPI. In the present study, we investigated intracellular mechanisms leading to an altered number of Ki67+ nuclei after stimulation of GPR55 by LPI and THC. Pharmacological analyses revealed a strongly involved PLC-IP3 signaling and cell-type-specific differences in Gα-, Gβγ-, RhoA-ROCK, and calcineurin signaling. Furthermore, immunochemical visualization of the calcineurin-dependent transcription factor NFAT revealed an unchanged subcellular localization after THC or LPI treatment. The data underline the cell-type-specific diversity of GPR55-associated signaling pathways in coupling to intracellular G proteins. Furthermore, this diversity might determine the outcome and the individual responsiveness of tumor cells to GPR55 stimulation by cannabin oids.

MACC1-induced migration in tumors: Current state and perspective

Malignant tumors are still a global, heavy health burden. Many tumor types cannot be treated curatively, underlining the need for new treatment targets. In recent years, metastasis associated in colon cancer 1 (MACC1) was identified as a promising biomarker and drug target, as it is promoting tumor migration, initiation, proliferation, and others in a multitude of solid cancers. Here, we will summarize the current knowledge about MACC1-induced tumor cell migration with a special focus on the cytoskeletal and adhesive systems. In addition, a brief overview of several in vitro models used for the analysis of cell migration is given. In this context, we will point to issues with the currently most prevalent models used to study MACC1-dependent migration. Lastly, open questions about MACC1-dependent effects on tumor cell migration will be addressed.

Jamming Transitions in Astrocytes and Glioblastoma Are Induced by Cell Density and Tension

Collective behavior of cells emerges from coordination of cell-cell-interactions and is important to wound healing, embryonic and tumor development. Depending on cell density and cell-cell interactions, a transition from a migratory, fluid-like unjammed state to a more static and solid-like jammed state or vice versa can occur. Here, we analyze collective migration dynamics of astrocytes and glioblastoma cells using live cell imaging. Furthermore, atomic force microscopy, traction force microscopy and spheroid generation assays were used to study cell adhesion, traction and mechanics. Perturbations of traction and adhesion were induced via ROCK or myosin II inhibition. Whereas astrocytes resided within a non-migratory, jammed state, glioblastoma were migratory and unjammed. Furthermore, we demonstrated that a switch from an unjammed to a jammed state was induced upon alteration of the equilibrium between cell-cell-adhesion and tension from adhesion to tension dominated, via inhibition of ROCK or myosin II. Such behavior has implications for understanding the infiltration of the brain by glioblastoma cells and may help to identify new strategies to develop anti-migratory drugs and strategies for glioblastoma-treatment.

MACC1-Induced Collective Migration Is Promoted by Proliferation Rather Than Single Cell Biomechanics

Metastasis-associated in colon cancer 1 (MACC1) is a marker for metastasis, tumor cell migration, and increased proliferation in colorectal cancer (CRC). Tumors with high MACC1 expression show a worse prognosis and higher invasion into neighboring structures. Yet, many facets of the pro-migratory effects are not fully understood. Atomic force microscopy and single cell live imaging were used to quantify biomechanical and migratory properties in low- and high-MACC1-expressing CRC cells. Furthermore, collective migration and expansion of small, cohesive cell colonies were analyzed using live cell imaging and particle image velocimetry. Lastly, the impact of proliferation on collective migration was determined by inhibition of proliferation using mitomycin. MACC1 did not affect elasticity, cortex tension, and single cell migration of CRC cells but promoted collective migration and colony expansion in vitro. Measurements of the local velocities in the dense cell layers revealed proliferation events as regions of high local speeds. Inhibition of proliferation via mitomycin abrogated the MACC1-associated effects on the collective migration speeds. A simple simulation revealed that the expansion of cell clusters without proliferation appeared to be determined mostly by single cell properties. MACC1 overexpression does not influence single cell biomechanics and migration but only collective migration in a proliferation-dependent manner. Thus, targeting proliferation in high-MACC1-expressing tumors may offer additional effects on cell migration.

Microglia-Dependent and Independent Brain Cytoprotective Effects of Mycophenolate Mofetil During Neuronal Damage

Acute lesions of the central nervous system often lead to permanent limiting deficits. In addition to the initial primary damage, accompanying neuroinflammation is responsible for progression of damage. Mycophenolate mofetil (MMF) as a selective inhibitor of inosine 5-monophosphate dehydrogenase (IMPDH) was shown to modulate the inflammatory response and promote neuronal survival when applied in specific time windows after neuronal injury. The application of brain cytoprotective therapeutics early after neuronal damage is a fundamental requirement for a successful immunomodulation approach. This study was designed to evaluate whether MMF can still mediate brain cytoprotection when applied in predefined short time intervals following CNS injury. Furthermore, the role of microglia and changes in IMPDH2 protein expression were assessed. Organotypic hippocampal slice cultures (OHSC) were used as an in vitro model and excitotoxically lesioned with N-methyl-aspartate (NMDA). Clodronate (Clo) was used to deplete microglia and analyze MMF mediated microglia independent effects. The temporal expression of IMPDH2 was studied in primary glial cell cultures treated with lipopolysaccharide (LPS). In excitotoxically lesioned OHSC a significant brain cytoprotective effect was observed between 8 and 36 h but not within 8 and 24 h after the NMDA damage. MMF mediated effects were mainly microglia dependent at 24, 36, 48 h after injury. However, further targets like astrocytes seem to be involved in protective effects 72 h post-injury. IMPDH2 expression was detected in primary microglia and astrocyte cell cultures. Our data indicate that MMF treatment in OHSC should still be started no later than 8–12 h after injury and should continue at least until 36 h post-injury. Microglia seem to be an essential mediator of the observed brain cytoprotective effects. However, a microglia-independent effect was also found, indicating involvement of astrocytes.

Nimodipine Exerts Time-Dependent Neuroprotective Effect after Excitotoxical Damage in Organotypic Slice Cultures

During injuries in the central nervous system, intrinsic protective processes become activated. However, cellular reactions, especially those of glia cells, are frequently unsatisfactory, and further exogenous protective mechanisms are necessary. Nimodipine, a lipophilic L-type calcium channel blocking agent is clinically used in the treatment of aneurysmal subarachnoid haemorrhage with neuroprotective effects in different models. Direct effects of nimodipine on neurons amongst others were observed in the hippocampus as well as its influence on both microglia and astrocytes. Earlier studies proposed that nimodipine protective actions occur not only via calcium channel-mediated vasodilatation but also via further time-dependent mechanisms. In this study, the effect of nimodipine application was investigated in different time frames on neuronal damage in excitotoxically lesioned organotypic hippocampal slice cultures. Nimodipine, but not nifedipine if pre-incubated for 4 h or co-applied with NMDA, was protective, indicating time dependency. Since blood vessels play no significant role in our model, intrinsic brain cell-dependent mechanisms seems to strongly be involved. We also examined the effect of nimodipine and nifedipine on microglia survival. Nimodipine seem to be a promising agent to reduce secondary damage and reduce excitotoxic damage.

Assessment of Neuronal Damage in Brain Slice Cultures Using Machine Learning Based on Spatial Features

Neuronal damage presents a major health issue necessitating extensive research to identify mechanisms of neuronal cell death and potential therapeutic targets. Commonly used models are slice cultures out of different brain regions extracted from mice or rats, excitotoxically, ischemic, or traumatically lesioned and subsequently treated with potential neuroprotective agents. Thereby cell death is regularly assessed by measuring the propidium iodide (PI) uptake or counting of PI-positive nuclei. The applied methods have a limited applicability, either in terms of objectivity and time consumption or regarding its applicability. Consequently, new tools for analysis are needed. Here, we present a framework to mimic manual counting using machine learning algorithms as tools for semantic segmentation of PI-positive dead cells in hippocampal slice cultures. Therefore, we trained a support vector machine (SVM) to classify images into either “high” or “low” neuronal damage and used naïve Bayes, discriminant analysis, random forest, and a multilayer perceptron (MLP) as classifiers for segmentation of dead cells. In our final models, pixel-wise accuracies of up to 0.97 were achieved using the MLP classifier. Furthermore, a SVM-based post-processing step was introduced to differentiate between false-positive and false-negative detections using morphological features. As only very few false-positive objects and thus training data remained when using the final model, this approach only mildly improved the results. A final object splitting step using Hough transformations was used to account for overlap, leading to a recall of up to 97.6% of the manually assigned PI-positive dead cells. Taken together, we present an analysis tool that can help to objectively and reproducibly analyze neuronal damage in brain-derived slice cultures, taking advantage of the morphology of pycnotic cells for segmentation, object splitting, and identification of false positives.

THC Reduces Ki67-Immunoreactive Cells Derived from Human Primary Glioblastoma in a GPR55-Dependent Manner

Glioblastoma (GBM) is the most frequent malignant tumor of the central nervous system in humans with a median survival time of less than 15 months. ∆⁹-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best-characterized components of Cannabis sativa plants with modulating effects on cannabinoid receptors 1 and 2 (CB₁ and CB₂) and on orphan receptors such as GPR18 or GPR55. Previous studies have demonstrated anti-tumorigenic effects of THC and CBD in several tumor entities including GBM, mostly mediated via CB₁ or CB₂. In this study, we investigated the non-CB₁/CB₂ effects of THC on the cell cycle of GBM cells isolated from human tumor samples. Cell cycle entry was measured after 24 h upon exposure by immunocytochemical analysis of Ki67 as proliferation marker. The Ki67-reducing effect of THC was abolished in the presence of CBD, whereas CBD alone did not cause any changes. To identify the responsible receptor for THC effects, we first characterized the cells regarding their expression of different cannabinoid receptors: CB₁, CB₂, GPR18, and GPR55. Secondly, the receptors were pharmacologically blocked by application of their selective antagonists AM281, AM630, O-1918, and CID16020046 (CID), respectively. All examined cells expressed the receptors, but only in presence of the GPR55 antagonist CID was the THC effect diminished. Stimulation with the GPR55 agonist lysophosphatidylinositol (LPI) revealed similar effects as obtained for THC. The LPI effects were also inhibited by CBD and CID, confirming a participation of GPR55 and suggesting its involvement in modifying the cell cycle of patient-derived GBM cells.

MACC1 driven alterations in cellular biomechanics facilitate cell motility in glioblastoma

Background

Metastasis-associated in colon cancer 1 (MACC1) is an established marker for metastasis and tumor cell migration in a multitude of tumor entities, including glioblastoma (GBM). Nevertheless, the mechanism underlying the increased migratory capacity in GBM is not comprehensively explored.

Methods

We performed live cell and atomic force microscopy measurements to assess cell migration and mechanical properties of MACC1 overexpressing GBM cells. We quantified MACC1 dependent dynamics of 3D aggregate formation. For mechanistic studies we measured the expression of key adhesion molecules using qRT-PCR, and MACC1 dependent changes in short term adhesion to fibronectin and laminin. We then determined changes in sub-cellular distribution of integrins and actin in dependence of MACC1, but also in microtubule and intermediate filament organization.

Results

MACC1 increased the migratory speed and elastic modulus of GBM cells, but decreased cell-cell adhesion and inhibited the formation of 3D aggregates. These effects were not associated with altered mRNA expression of several key adhesion molecules or altered short-term affinity to laminin and fibronectin. MACC1 did neither change the organization of the microtubule nor intermediate filament cytoskeleton, but resulted in increased amounts of protrusive actin on laminin.

Conclusion

MACC1 overexpression increases elastic modulus and migration and reduces adhesion of GBM cells thereby impeding 3D aggregate formation. The underlying molecular mechanism is independent on the organization of microtubules, intermediate filaments and several key adhesion molecules, but depends on adhesion to laminin. Thus, targeting re-organization of the cytoskeleton and cell motility via MACC1 may offer a treatment option to impede GBM spreading.

Opposite Effects of Neuroprotective Cannabinoids, Palmitoylethanolamide, and 2-Arachidonoylglycerol on Function and Morphology of Microglia

Various studies performed in cultured cells and in in vivo models of neuronal damage showed that cannabinoids exert a neuroprotective effect. The increase in cannabinoids and cannabinoid like substances after stroke has been postulated to limit the content of neuronal injury. As well-accepted, inflammation, and neuronal damage are coupled processes and microglial cells as the main intrinsic immunological effector within the brain play a central role in their regulation. Treatment with the endocannabinoid, 2-arachidonoylglycerol (2-AG) or the endocannabinoid-like substance, palmitoylethanolamide (PEA) affected microglial cells and led to a decrease in the number of damaged neurons after excitotoxical lesion in organotypic hippocampal slice cultures (OHSC). 2-AG activated abnormal cannabidiol (abn-CBD) receptor, PEA was shown to mediate neuroprotection via peroxisome proliferator-activated receptor (PPAR)α. Despite the known neuroprotective and anti-inflammatory properties, the potential synergistic effect, namely possible entourage effect after treatment with the combination of these two protective cannabinoids has not been examined yet. After excitotoxical lesion OHSC were treated with PEA, 2-AG or a combination of both and the number of damaged neurons was evaluated. To investigate the role of microglial cells in PEA and 2-AG mediated protection, primary microglial cell cultures were treated with lipopolysaccharide (LPS) and 2-AG, PEA or a combination of those. Thereafter, we measured NO production, ramification index, proliferation and PPARα distribution in microglial cells. While PEA or 2-AG alone were neuroprotective, their co-application vanished the protective effect. This behavior was independent of microglial cells. Furthermore, PEA and 2-AG had contrary effects on ramification index and on NO production. No significant changes were observed in the proliferation rate of microglial cells after treatment. The expression of PPARα was not changed upon stimulation with PEA or 2-AG, but the distribution was significantly altered. 2-AG and PEA mediated neuroprotection was abolished when co-applied. Both cannabinoids exert contrary effects on morphology and function of microglial cells. Co-application of both cannabinoids with different targets did not lead to a positive additive effect as expected, presumably due to the contrary polarization of microglial cells.

Aerial ungulate surveys with a combination of infrared and high–resolution natural colour images

Information on animal population sizes is crucial for wildlife management. In aerial surveys, we used a silent light aircraft (microlight) and a combination of a computer–linked thermal infrared camera (640 x 480 pixels) to detect ungulates and high–resolution visual images (5,616 x 3,744 pixels) to identify specific species. From winter 2008/2009 to winter 2010/2011, we flew 48 missions over three German national parks and a German/ French biosphere reserve. Within each study area, we followed non–overlapping linear transects with a flying altitude ~450 m above ground level and scanned 1,500–2,000 ha every two hours of flight time. Animals best detected and identified were red deer and fallow deer. Detection rates with respect to the type and density of vegetation cover ranged from 0% (young spruce) to 75% (young defoliated beech) to 100% (open land). This non–invasive method is cost–effective and suitable for many landscapes.

Non-invasive genetic approaches for estimation of ungulate population size: a study on roe deer (Capreolus capreolus) based on faeces

Estimating population size is particularly difficult for animal species living in concealing habitats with dense vegetation. This is the case for roe deer as for many other ungulates. Our objective was to develop a non–invasive genetic capture–mark–recapture approach based on roe deer faeces collected along transects. In a pilot study, we collected 1,790 roe deer faeces during five sampling days in a forested study area in south western Germany. We extracted DNA from 410 of these samples and carried out microsatellite analysis using seven dinucleotide markers. The analyses resulted in 328 useable consensus genotypes which were assigned to 174 individuals. The population size estimated using a Bayesian approach was 94 (82–111) male and 136 (121–156) female roe deer. Our study shows that non–invasive genetic methods are a valuable management tool for roe deer.

Molecular cytogenetic analysis of Agropyron chromatin specifying resistance to barley yellow dwarf virus in wheat

Nine families of bread wheat (TC5, TC6, TC7, TC8, TC9, TC10, TC14, 5395-(243AA), and 5395) with resistance to barley yellow dwarf virus and containing putative translocations between wheat and a group 7 chromosome of Agropyron intermedium (L1 disomic addition line, 7Ai#1 chromosome) induced by homoeologous pairing or tissue culture were analyzed. C-banding, genomic in situ hybridization (GISH), and restriction fragment length polymorphism (RFLP) in combination with repetitive Agropyron-specific sequences and deletion mapping in wheat were used to determine the relative locations of the translocation breakpoints and the size of the transferred alien chromatin segments in hexaploid wheat-Agropyron translocation lines. All homoeologous compensating lines had complete 7Ai#1 or translocated 7Ai#1-7D chromosomes that substitute for chromosome 7D. Two complete 7Ai#1 (7D) substitution lines (5395-(243AA) and 5395), one T1BS-7Ai#1S∙7Ai#1L addition line (TC7), and two different translocation types, T7DS-7Ai#1S∙7Ai#1L (TC5, TC6, TC8, TC9, and TC10) and T7DS∙7DL-7Ai#1L (TC14), substituting for chromosome 7D were identified. The substitution line 5395-(243AA) had a reciprocal T1BS∙1BL-4BS/T1BL-4BS∙4BL translocation. TC14 has a 6G (6B) substitution. The RFLP data from deletion mapping studies in wheat using 37 group 7 clones provided 10 molecular tagged chromosome regions for homoeologous and syntenic group 7 wheat or Agropyron chromosomes. Together with GISH we identified three different sizes of the transferred Agropyron chromosome segments with approximate breakpoints at fraction length (FL) 0.33 in the short arm of chromosome T7DS-7Ai#1S∙7Ai#1L (TC5, TC6, TC8, TC9, and TC10) and another at FL 0.37 of the nonhomoeologous translocated chromosome T1BS-7Ai#1S∙7Ai#1L (TC7). One breakpoint was identified in the long arm of chromosome T7DS∙7DL-7Ai#1L (TC14) at FL 0.56. We detected some nonreciprocal translocations for the most proximal region of the chromosome arm of 7DL, which resulted in small duplications. Key words : C-banding, genomic in situ hybridization (GISH), physical mapping, translocation mapping, RFLP analysis.

[PCO syndrome--is it an indication for bariatric surgery?]

BACKGROUND

The polycystic ovary syndrome (PCOS) is the most frequent cause of female infertility with an estimated prevalence of 6-10% in premenopausal women. Due to its long-term metabolic and cardiovascular consequences, it poses a severe health problem. Visceral obesity and subsequent insulin resistance represent the core pathophysiology of PCOS, clearly suggesting that measures to reduce abdominal obesity should be pursued.

METHODS

Between February 1995 and October 2006, 204 patients underwent bariatric surgery in the SRH Hospital of Gera. 75% of the patients were female and three of them were suffering preoperatively from polycystic ovary syndrome and metabolic syndrome.

RESULTS

104 months after laparoscopic adjustable gastric banding, the excess body weight loss (EBWL) was 49, 67 and 41% in these three patients, respectively. Glucose levels normalised completely. One patient became pregnant after weight reduction.

CONCLUSIONS

In PCOS with metabolic syndrome, bariatric surgery is an option to reduce weight and to treat associated metabolic disorders. Surgery should be performed based on the body mass index, the metabolic disorders, and the wish of the patient to become pregnant.

Experiences of two centers of bariatric surgery in the treatment of intragastrale band migration after gastric banding-the importance of the German multicenter observational study for quality assurance in obesity surgery 2005 and 2006

BACKGROUND

Adjustable silicone gastric banding (ASGB) is an effective treatment in morbid obesity. Band migration is a long-term complication. Causes, clinical symptoms, timing and incidence are investigated in single centres only. In Germany, since January 1st, 2005, practice in bariatric surgery has been investigated in German prospective multicenter trial for quality assurance in obesity surgery.

MATERIALS AND METHODS

All patients underwent ASGB in two centres of bariatric surgery in Germany were prospectively registered using a computer-based data form. Patients with band migration were retrospectively evaluated, in particular, causes and characteristics of its management. The results were correlated with data obtained from the German prospective multicentre trial.

RESULTS

In total, 493 patients were enrolled in the study from February 1995 to February 2007. The follow-up rate was 79.9% (mean follow-up time period, 78.7 months; range, 2-148 months). Fifteen patients (3.0%) developed migration. In 14 cases, migration occurred within the range of 30-86 months after implantation. In one case, migration occurred 10 months after repositioning of the band. In the German multicentre trial, 629 patients underwent surgery during 2005 and 827 patients in 2006. In both periods, 74.4% of the patients were female and 25.6% male. The most frequently performed operation was ASGB (46.8%) followed by Roux-en-Y gastric bypass (38.5%).

CONCLUSION

Band migration requires band removal. Different symptoms and complications influence the kind of band removal. Multicentre data were evident in the case of high long-term complication rate after ASGB. Data of the German multicentre trial show the trend from restrictive bariatric procedures to malabsorptive approach.

Epiphrenic Esophageal Diverticulum after Laparoscopic Placement of an Adjustable Gastric Band

A morbidly obese woman (BMI 56 kg/m2) in 1998 underwent laparoscopic placement of an adjustable gastric band by the perigastric approach. 5 years later, she complained of reflux and weight regain. X-ray with contrast revealed pouch dilatation. She subsequently underwent a laparoscopic revision including retrocardia band replacement using the pars flaccida technique. During the further course, an epiphrenic diverticulum was diagnosed. Because of danger of perforation of the large thin-walled diverticulum and the esophageal motility disorder, the band was laparoscopically removed and the diverticulum was resected via a transhiatal approach. This case presents a very rare complication after placement of a gastric band and its successful management.

Rhabdomyolysis after biliopancreatic diversion with duodenal switch

Rhabdomyolysis is an uncommon event in bariatric surgery. It can be caused by ischemia, crush injury, alcohol ingestion and drug intake, and as a consequence renal failure can develop. A few reports indicate that patients undergoing bariatric surgical intervention are at risk for rhabdomyolysis. A super-obese male (BMI 52 kg/m2) is reported, who underwent laparoscopic biliopancreatic diversion with duodenal switch (BPD/DS). Operative time was 265 minutes, and the BPD/DS operation was uneventful. Post-operatively, the patient complained of pain in both hips and the left shoulder, and suffered oliguria. He was treated with fluids (isotonic saline), bicarbonate, and mannitol. Despite this, he developed renal failure, which subsequently required hemodialysis. The patient died from arrhythmia and cardiac arrest on the 8th postoperative day. Obese patients undergoing bariatric surgery are at risk of rhabdomyolysis. Prolonged compression of the muscles during the surgical intervention, in long laparoscopic procedures, predisposes to this complication.

[Long-term results after gastric banding]

BACKGROUND

Adjustable gastric banding is a popular bariatric operation in Europe. The rate of long-term complications like pouch dilatation, slippage and band migration and the long-term effect of weight loss are reported in meta-analysis and few studies for a period of more than five years. We report on experiences after gastric banding.

METHODS

Over a period of 10 years 168 patients with morbid obesity were treated with gastric banding. Preoperative data, postoperative weight loss and long-term complications were prospectively obtained and retrospectively analyzed.

RESULTS

Mean age of the patients was 41.7 years with a mean preoperative BMI of 49.6 kg/m2. No intraoperative or postoperative death occurred in the first 30 postoperative days. Intraoperative conversion rate was 7.1 %. 79.8 % of the patients (n = 134) were available for follow up (mean follow-up time 66.7 months). Long-term complications occurred in 22.5 % of the patients. 30 complications (17.8 %) were related to the band and 8 (4.7 %) to the access-port or to the tube. Mean excess weight loss was 39.6, 47.3, 44.2, 43.4 and 32 % after 1, 2, 4, 5 and 8 years.

CONCLUSIONS

Laparoscopic gastric banding can achieve an effective weight loss. However band-related and functional complications will influence the late outcome. Pathways to choose the best surgical method for the individual patient are necessary to reduce failures after gastric banding.

[Band migration. A late complication of gastric banding]

BACKGROUND

Adjustable silicone gastric banding is an effective and safe treatment for morbid obesity. Migration of the band through the stomach wall is a long-term complication. The causes, clinical symptoms, timing, and incidence of band migration have not yet been investigated.

METHODS

We report our experience over 9 years. Between February 1995 and February 2004, we performed adjustable silicone gastric banding in 161 patients, with follow-up of about 90.5% of cases. Mean follow-up time was 60.4 months. Cases of erosion were studied retrospectively.

RESULTS

Eight patients (4.9%) developed band migration. In seven, the migration occurred between 30 and 86 months after band implantation. In one case, the migration occurred 10 months after laparoscopic repositioning of the band to avoid pouch dilatation. In all cases, the bands were removed.

CONCLUSION

Band migration is a late complication after gastric banding that requires band removal. Various symptoms and complications of band migration influence the kind of band removal. The causes of band migration and its treatment are discussed.

Bacterial artificial chromosome-derived molecular markers for early bolting in sugar beet

Early bolting in sugar beet (Beta vulgaris L.) is controlled by the dominant gene B. From an incomplete physical map around the B gene, 18 bacterial artificial chromosomes (BACs) were selected for marker development. Three BACs were shotgun-sequenced, and 61 open reading frames (ORFs) were identified. Together with 104 BAC ends from 54 BACs, a total number of 55,464 nucleotides were sequenced. Of these, 37 BAC ends and 12 ORFs were selected for marker development. Thirty-one percent of the sequences were found to be single copy and 24%, low copy. From these sequences, 15 markers from ten different BACs were developed. Ten polymorphisms were determined by simple agarose gel electrophoresis of either restricted or non-restricted PCR products. Another five markers were determined by tetra-primer amplification refractory mutation system-PCR. In order to select candidate BACs for cloning the gene, genetic linkage between seven markers and the bolting gene was calculated using 1,617 plants from an F2 population segregating for early bolting. The recombination values ranged between 0.0033 and 0.0201. In addition, a set of 41 wild and cultivated Beta accessions differing in their early bolting character was genotyped with seven markers. A common haplotype encompassing two marker loci and the b allele was found in all sugar beet varieties, indicating complete linkage disequilibrium between these loci. This suggests that the bolting gene is located in close vicinity to these markers, and the corresponding BACs can be used for cloning the gene.

Ultrastructural analysis of chromatin in meiosis I + II of rye (Secale cereale L.)

Scanning electron microscopy (SEM) proves to be an appropriate technique for imaging chromatin organization in meiosis I and II of rye (Secale cereale) down to a resolution of a few nanometers. It could be shown for the first time that organization of basic structural elements (coiled and parallel fibers, chromomeres) changes dramatically during the progression to metaphase I and II. Controlled loosening with proteinase K (after fixation with glutaraldehyde) provides an enhanced insight into chromosome architecture even of highly condensed stages of meiosis. By selective staining with platinum blue, DNA content and distribution can be visualized within compact chromosomes as well as in a complex arrangement of fibers. Chromatin interconnecting threads, which are typically observed in prophase I between homologous and non-homologous chromosomes, stain clearly for DNA. In zygotene transversion of chromatid strands to their homologous counterparts becomes evident. In pachytene segments of synapsed and non-synapsed homologs alternate. At synapsed regions pairing is so intimate that homologous chromosomes form one filament of structural entity. Chiasmata are characterized by chromatid strands which traverse from one homolog to its counterpart. Bivalents are characteristically fused at their telomeric regions. In metaphase I and II there is no structural evidence for primary and secondary constrictions.

[Rare tumors of the pancreas]

From 1984 to 2001, 486 operations were carried out at the surgical clinic in Gera for pancreatic neoplasms, including 49 patients with rare neoplasms of the pancreas. In 23 patients malignant pancreatic tumors were present (9 solitary metastases, 9 endocrine carcinomas, 2 cystadenocarcinomas, 2 schwannomas and one non-Hodgkin's lymphoma). In 28 benign lesions a resection of the tumor was performed, concerning 8 insulinomas, 8 serous cystadenomas, 3 mucinous cystadenomas and 4 rare cystic tumors. A sarcoidosis, an autoimmune pancreatitis and a radiation fibrosis were diagnosed in 3 patients operated under the suspicion of a malignant pancreatic tumor. By means of own case examples and data from the literature these rare entities are described with their diagnostic and therapeutic special features.

[Lesions of the spleen in chronic pancreatitis by thrombophlebetic splenomegaly and cyst penetration]

Chronic pancreatitis leads to changes of nearby organs with possible acute and chronic complications including lesions of the spleen. Among 341 patients operated upon between January 1981 and June 2002 in the surgical department Gera, we found 7 spontaneous spleen ruptures or such after minimal trauma and 4 pseudocysts, which expanded to the splenic hilus. In all cases splenectomy was carried out with resection of the tail of the pancreas with or without drainage of the pancreas. 2 patients with a history of splenectomy after minimal trauma underwent duodenum-preserving resection of the pancreatic head to Frey, and distal pancreatectomy, resp.

CONCLUSIONS

Lesions of the spleen belong to the rare complications of chronic pancreatitis. With known case history and mostly delayed course, the operative concept must be concentrated not only on the splenic lesion but also on the therapy of the chronic pancreatitis.

A bacterial artificial chromosome (BAC) library of sugar beet and a physical map of the region encompassing the bolting gene B

In sugar beet (Beta vulgaris L.), early bolting is caused by a single dominant gene, designated B. Twenty AFLP markers selected from a 7.8-cM segment of the B region on chromosome 2 were used to screen a YAC library, and a first-generation physical map including the B gene, made up of 11 YACs, was established. Because the genome coverage of the YAC library was low, a BAC library was constructed in the vector pBeloBAC11. This library consists of 57,600 clones with an average insert size of 116 kb, corresponding to 8.8 genome equivalents. Screening of the BAC library with chloroplast and mitochondrial DNA probes indicated that less than 0.1% of the clones contained organelle-derived DNA. To fill the gaps in the physical map around the B gene, the BAC library was screened with four AFLP markers and 10 YAC-derived probes. In total, 54 different BACs were identified. Overlaps between BACs were detected by using BAC termini amplified by PCR as probes, and by RFLP fingerprinting. In this way, a minimal tiling path of the central 4.6-cM region was constructed, which consists of 14 BACs. The B locus was localized to a 360-kb contig, a size which makes positional cloning of the gene feasible.

C-to-U conversion in the intercistronic ndhI/ ndhG RNA of plastids from monocot plants: conventional editing in an unconventional small reading frame?

Editing of plastid RNAs proceeds by C-to-U, in hornwort species also by extensive U-to-C, transitions, which predominantly lead to the restoration of codons for structurally and/or functionally important, conserved amino acid residues. So far, only one instance of editing outside coding regions has been reported - in the psbL/ psbF intergenic region of Ginkgo biloba. This site was proposed to have no functional importance. Here we present an evaluation of an editing site in the ndhI/ ndhG intergenic region in a related group of monocot plants. Efficient editing of this site, as well as the phylogenetic conservation of the resulting uridine residue, point at an important role for the sequence restored by editing. Two potential functions can be envisaged. (1) RNA secondary structure predictions suggest that the C-to-U conversion at this site can lead to a modified stem/loop structure of the ndhG 5' UTR, which could influence ndhG expression. (2) Alternatively, editing of the ndhI/ ndhG intergenic region may tag a so far unidentified small (12-codon) ORF, and lead to the restoration of a conserved phenylalanine codon. A screen with specific antibodies elicited against the putative peptide failed to detect such a peptide in chloroplast fractions. However, this failure may be attributable to its low and/or development-specific expression.

Comparative genomic in situ hybridization (cGISH) analysis on plant chromosomes revealed by labelled Arabidopsis DNA

A new approach for comparative cytogenetic banding analysis of plant chromosomes has been established. The comparative GISH (cGISH) technique is universally applicable to various complex genomes of Monocotyledonae (Triticum aestivum, Agropyron elongatum, Secale cereale, Hordeum vulgare, Allium cepa, Muscari armenaticum and Lilium longiflorum) and Dicotyledonae (Vicia faba, Beta vulgaris, Arabidopsis thaliana). Labelled total genomic DNA of A. thaliana generates signals at conserved chromosome regions. The nucleolus organizing regions (NORs) containing the majority of tandemly repeated rDNA sequences, N-band regions containing satellite DNA, conserved homologous sequences at telomeres and additional chromosome-characteristic markers were detected in heterologous FISH experiments. Multicolour FISH analysis with repetitive DNA probes simultaneously revealed the chromosome assignment of 56 cGISH signals in rye and 61 cGISH signals in barley. Further advantages of this technique are: (1) the fast and straightforward preparation of the probe; (2) the generation of signals with high intensity and reproducibility even without signal amplification; and (3) no requirement of species-specific sequences suitable for molecular karyotype analysis. Hybridization can be performed without competitive DNA. Signal detection without significant background is possible under low stringency conditions. The universal application of this fast and simple one-step fluorescence banding technique for plant cytogenetic and plant genome evolution is discussed.

[Intraoperative diagnosis of pheochromocytoma preoperative symptoms in a case of Recklinghausen's disease]

Phaechromocytoma is a rare catecholamine secreting tumor, which occasionally presents as a life threatening crisis in association with surgery and anesthesia. We report a 58-year-old women with known Recklinghausen's disease who was admitted for elective resection of a pancreas tail cystadenoma. A cystadenocarcinoma was taken into account differential diagnostically. No clinical symtoms or signs pointing to a hormone active tumor were found preoperatively. After opening of the abdomen and palpation of the tumor, a hypertensive crisis occurred accompanied by considerable tachycardia, leading to the tentative diagnosis of a phaeochromocytoma in connection to the known phacomatosis. The hypertensive crisis was treated with nitroglycerin and esmolol. The putative tumor of the pancreas represented itself as an adrenal tumor without relationship to the pancreas. Following ligature of the suprarenal vein, antihypertensive therapy could be finished. For stabilization of blood pressure a noradrenaline application was necessary in descending dosage over a period of two days. The further postoperative course was without complications. The results of the urine catecholamine measurements and histological examinations confirmed the intraoperative diagnosis. An unidentified phaeochromocytoma is a vital threat for patients during surgery and anesthesia. Phaeochromocytomas are observed in patients suffering from Recklinghausen's disease (and other phacomatoses) in an above average incidence. Therefore, such a tumor should be excluded in these patients before elective surgery even if the patient does not show symptoms (asymptomatic phaeochromocytomas occur). The determination of catecholamines in 24 hour urine collections is an easy and specific diagnostic procedure and should be used in patients suffering from phacomatoses before elective surgery.

[The upside-down stomach. Laparoscopic treatment is possible]

An upside-down-stomach, usually occurring in eldery patients describes an extreme case of paraesophageal hernia. Due to the possibility of life threatening complications there is an urgent need for surgical intervention. In 1998 three patients suffering from complete upside-down-stomach were treated by laparoscopic surgery at our hospital. Two of them received a hiatoplastic with fundo- and corpophrenicopexy. In one case we did a 360 degrees-floppy Nissen's-fundoplication. Perioperatively, one patient developed a left sided pneumothorax Long-term follow-up 6 months postoperatively in our out-patient department revealed unconspicuous clinical and gastroscopical findings and high patient satisfaction with postoperative outcome. Our case reports show the possibility of adequate operating on upside-down-stomach by means of laparoscopic surgery. Minimal invasive methods provide a good overlock on the operating field and are poor in complications when done by an experienced surgeon, so that patients may profit from comfort of laparoscopic surgery.

[Acute cholecystitis--primary laparoscopic procedure]

The role of laparoscopic cholecystectomy on patients with histologically confirmed acute cholecystitis is still controversial. From January 1992 to December 1996, 228 cholecystectomies were performed for acute cholecystitis and a total of 104 patients were operated on conventionally and 124 patients underwent laparoscopic surgery. In a prospective study we compared the conventional with the laparoscopic technique. The results indicated that in 19 patients (15.3%) treated initially with the laparoscopic technique, a switch to laparotomy was required. The operating duration was lower for conventional cholecystectomy (75 min versus 95 min). However, surgical and nonsurgical complication rates were similar in both groups. The period of hospitalization was shorter in laparoscopic operations. According to these results we believe that laparoscopic cholecystectomy in patients with acute cholecystitis is a safe and effective procedure. The patients will benefit from the advantages of laparoscopic surgery without increased morbidity.

[Preoperative diagnosis in laparoscopic cholecystectomy: is intravenous cholangiography currently still justified?]

Laparocopic cholecystectomy requires essentially the safe exclusion of choledocholithias. The aim of this study was to compare the intravenous cholangiography and ERCP in addition to a basic program (case history, laboratory results ultrasound) with references to the diagnostic ability and therapeutic consequences in patients with choledocholithiasis. The results show, that the intravenous cholangiography not provides extra important informations after the case history, ultrasound and laboratory findings and therefore its general use is not justified. Instead of the intravenous cholangiography the preoperative ERCP should be performed generously if choledocholithiasis is suspected, especially because the ERCP offers the possibility to extract the stone.

Repeated DNA sequences isolated by microdissection. II. Comparative analysis in Hordeum vulgare and Triticum aestivum

The genomic organization of two satellite DNA sequences, pHvMWG2314 and pHvMWG2315, of barley (Hordeum vulgare, 2n=14, HH) was studied by comparative in situ hybridization (ISH) and PCR analysis. Both sequences are members of different RsaI families. The sequence pHvMWG2314 is a new satellite element with a monomer unit of 73 bp which is moderately amplified in different grasses and occurs in interstitial clusters on D-genome chromosomes of hexaploid wheat (Triticum aestivum, 2n=42, AABBDD). The 331-bp monomer pHvMWG2315 belongs to a tandemly amplified repetitive sequence family that is present in the Poaceae and preferentially amplified in Aegilops squarrosa (2n=14, DD), H. vulgare and Agropyron elongatum. (2n=14, EE). The first described representative of this family was pAs 1 from Ae. squarrosa. Different sequences of one satellite DNA family were amplified from Ae. squarrosa, A. elongatum and H. vulgare using PCR. Characteristic differences between members of the D and H genome occurred in a variable region which is flanked by two conserved segments. The heterogeneity within this element was exploited for the cytogenetic analysis of Triticeae genomes and chromosomes. Comparative ISH with pHvMWG2315 identified individual wheat and barley chromosomes under low (75%) and high (85%) hybridization stringency in homologous and heterologous systems. We propose the designation Tas330 for the Triticeae amplified sequence (Tas) satellite family with a 330 bp average monomer length.

Physical and topographical mapping among Triticeae chromosomes

Three principal approaches have been used in our laboratory to analyze Triticeae genomes. (i) Synteny analysis: synteny among different Gramineae genomes was studied employing the elegant system of the Agropyron chromosome-induced deletion lines of wheat. Deletion mapping, predominantly of the homoeologous group 7 chromosomes, has led to the construction of a high density physical consensus map of wheat. The integration of wheat, barley and oat RFLP markers proves the colinearity between the wheat A-, B- and D-genomes, the H-genome of barley, and the E-genome of Agropyron. (ii) Light microscopic in situ techniques: the recent improvement of a drop technique for plant protoplasts was crucial for the sensitivity enhancement of fluorescence in situ hybridization (FISH), the efficient preparation of plant chromosomes for high resolution scanning electron microscopy, mapping of low-copy sequences, and comparative in situ hybridization. A tandemly amplified repetitive sequence element from microdissected barley chromosomes has enabled the karyotyping of Gramineae genomes in a single step. We have isolated and characterized members of this element family from other Triticeae species using PCR. The significant interspecific sequence differences were useful to identify single plant genomes, chromosomes and chromosome segments via post-hybridization washes under different stringency conditions. These sequences are also useful for simultaneous double or triple hybridization experiments in an attempt to localize new sequences on specific chromosomes or chromosome segments. The physical mapping of the Sec-1 locus has been refined on the satellite of chromosome 1R of rye, and the syntenic locus on barley chromosome 1H was identified. (iii) Physical mapping of rDNA sequences by high resolution electron microscopy: a method was developed for in situ hybridization and signal detection using high resolution field emission scanning electron microscopy and a backscattered electron detector. Colloidal gold particles were localized on chromosome structures resembling the 30 nm fibre. An rDNA probe was located in the secondary constriction and the highly compact adjacent regions of barley chromosomes.

Repeated DNA sequences isolated by microdissection. I. Karyotyping of barley (Hordeum vulgare L.)

We report on microdissection, cloning and sequence, and Southern and fluorescence in situ hybridization (FISH) analysis of one moderately and one highly amplified repetitive DNA element, pHvMWG2314 and pHvMWG2315, respectively, isolated from barley (Hordeum vulgare L.) chromosome arm 3HL. The pHvMWG2315 sequence hybridizes to all 14 telomeric or subtelomeric regions of the barley chromosomes as determined by FISH. The 50 different hybridization sites that include intercalary signals allow the discrimination of all 14 chromosome arms and the construction of a kariotype of barley. The tandemly repeated subtelomeric element of 331 bp exists in all Triticeae species tested (H. vulgare, Agropyron elongatum, Secale cereale, Triticum tauschii, T. turgidum, and T. aestivum). It is AT rich (66%), exibits 84% sequence homology to subfragments of the D genome ¿specific¿ 1-kb element pAs1 of T. tauscii and 75% homology to interspersed genome-specific DNA sequence pHcKB6 from H. chilence. The repetitive sequence pHvMWG2314 is moderately amplified in barley and highly amplified in hexaploid wheat. The in situ experiments revealed no distinct signals on barley chromosomes, indicating a dispersed character for the sequence. The significance of the results for the identification of chromosomes and chromosome aberrations in FISH experiments are discussed.

Comparison of wheat physical maps with barley linkage maps for group 7 chromosomes

Comparative genetic maps among the Triticeae or Gramineae provide the possibility for combining the genetics, mapping information and molecular-marker resources between different species. Dense genetic linkage maps of wheat and barley, which have a common array of molecular markers, along with deletion-based chromosome maps of Triticum aestivum L. will facilitate the construction of an integrated molecular marker-based map for the Triticeae. A set of 21 cDNA and genomic DNA clones, which had previously been used to map barley chromosome 1 (7H), were used to physically map wheat chromosomes 7A, 7B and 7D. A comparative map was constructed to estimate the degree of linkage conservation and synteny of chromosome segments between the group 7 chromosomes of the two species. The results reveal extensive homoeologies between these chromosomes, and the first evidence for an interstitial inversion on the short arm of a barley chromosome compared to the wheat homoeologue has been obtained. In a cytogenetically-based physical map of group 7 chromosomes that contain restriction-fragment-length polymorphic DNA (RFLP) and random amplified polymorphic DNA (RAPD) markers, the marker density in the most distal third of the chromosome arms was two-times higher than in the proximal region. The recombination rate in the distal third of each arm appears to be 8-15 times greater than in the proximal third of each arm where recombination of wheat chromosomes is suppressed.

Characterization of deletions in common wheat induced by an Aegilops cylindrica chromosome: detection of multiple chromosome rearrangements

An Aegilops cylindrica chromosome induces terminal deletions of chromosomes in wheat as identified by C-banding. We are constructing high-density physical maps of wheat chromosomes and have detected additional chromosome rearrangements. Among 63 lines with chromosomal subarm deletions in group 7 chromosomes, 7 lines (11.1%) were shown to harbor additional chromosome rearrangements. Two other lines were also omitted from the physical mapping because of the nature of the breakpoint calculations. The presence or absence of chromosome-specific restriction fragment length polymorphism (RFLP) or random amplified polymorphic DNA (RAPD) markers indicated that additional interstitial deletions are present in 3 lines (4.8%) with deletions in the short chromosome arms and in 4 lines (6.3%) with deletions in the long chromosome arms. We also used chromosome pairing analysis of F1 plants of deletion lines with double ditelosomic lines of 'Chinese Spring' wheat to detect small terminal deletions. The deletion of the most distal 1% of chromosome arm 7AL was associated with a pairing reduction of 60%.

Comparison of genetic and physical maps of group 7 chromosomes from Triticum aestivum L

We present a high density physical map of homoeologous group 7 chromosomes from Triticum aestivum L. using a series of 54 deletion lines, 6 random amplified polymorphic DNA (RAPD) markers and 91 cDNA or genomic DNA clones from wheat, barley and oat. So far, 51 chromosome segments have been distinguished by molecular markers, and 54 homoeoloci have been allocated among chromosomes 7A, 7B and 7D. The linear order of molecular markers along the chromosomes is almost identical in the A- B- and D-genome of wheat. In addition, there is colinearity between the physical and genetic maps of chromosomes 7A, 7B and 7D from T. aestivum, indicating gene synteny among the Triticeae. However, comparison of the physical map of chromosome 7D from T. aestivum with the genetic map from Triticum tauschii some markers have been shown to be physically allocated with distortion in more distal chromosome regions. The integration of genetic and physical maps could assist in estimating the frequency and distribution of recombination in defined regions along the chromosome. Physical distance did not correlate with genetic distance. A dense map facilitates the detection of multiple rearrangements. We present the first evidence for an interstitial inversion either on chromosome arm 7AS or 7DS of Chinese Spring. Molecularly tagged chromosome regions (MTCRs) provide landmarks for long-range mapping of DNA fragments.

Amplification of DNA sequences in wheat and its relatives: the Dgas44 and R350 families of repetitive sequences

The sequence of a Triticum tauschii genomic clone representing a family of D-genome amplified DNA sequences, designated Dgas44, is reported. The Dgas44 sequence occurs on all chromosomes of the D genome of wheat, Triticum aestivum, and in situ hybridization revealed it to be evenly dispersed on all seven chromosome pairs. An internal HindIII fragment of Dgas44, designated Dgas44-3, defines the highly amplified region that is specific to the D genome. The polymerase chain reaction was used to amplify a 236-bp fragment within Dgas44-3 from chromosomes 1D, 2D, 3D, 4D, 5D, and 7D, and identical copies of this region of the Dgas44-3 sequence were found among the isolates from each of the chromosomes. The Dgas44-3 sequence population from specific chromosomes differed on average by 0.22% from the original Dgas44 sequence. The Dgas44 sequence was found to differentiate between the D genome present in T. aestivum, T. tauschii, hexaploid T. crassum, T. cylindricum, T. ventricosum, in which the sequence was present in a highly amplified form and T. juvenale, T. syriacum, and tetraploid T. crassum where the sequence family was difficult to detect. Another class of amplified sequences previously considered to be rye "specific." R350, was isolated from tetraploid wheat and its dispersed distribution on chromosomes was similar to the Dgas44 family in T. tauschii. In contrast with the Dgas44 sequence family, genome specificity for the remnant R350 sequence family was not evident since it was present on all wheat chromosomes.

C-banding polymorphism and linkage of nonhomoeologous RFLP loci in the D genome progenitor of wheat

Chromosomes from four different accessions of Triticum tauschii, used as parents in generating F2 populations for RFLP genetic linkage map construction, were analyzed by C-banding. The accessions consist of the varietal taxa strangulata (AUS 21929) and meyeri (AUS 18911), and two genotypes of var. typica (AUS 18902 and CPI 110730 from Iran and Afghanistan, respectively). Chromosomes 1D and 7D of T. tauschii var. typica AUS 18902 are involved in a reciprocal interchange forming translocated chromosomes, T1DS.7DL and T7DS.1DL, with tbe breakpoints being located within the centrometric region. The formation of quadrivalent configuration in F1 hybrids provided further confirmation of the reciprocal translocation. Genetic linkage mapping of additional RFLP markers located on homoeologous group 1 and 7 chromosomes showed consistent linkage to a composite group of proximal markers on chromosomes 1D and 7D of a previously published map derived from the F2 progeny of AUS 18902 x AUS 18911. A high frequency of RFLP genotypes transmitted by the translocation parent was prevalent in the proximal regions of chromosomes 1D and 7D. Genotypic frequencies expected of the nontranslocated parental RFLP markers was evident only in the distal regions of these chromosomes.

Stabilization of tetraploid triticale with chromosomes from Triticum aestivum (ABD)(ABD)RR (2n = 28)

F1 hybrids with the genome constitution ABDERR (2n = 6x = 42) or ABDE(AB)RR (2n = 7x = 49), selected from crosses between either an octoploid Triticum aestivum/Thinopyrum elongatun amphiploid and tetraploid Secale cereale (AABBDDEE x RRRR) or autoallohexaploid triticale [AABBDDEE x (AB)(AB)RRRR], were backcrossed to tetraploid triticale (AB)(AB)RR and selfed for six generations. Thirty-three different tetraploid F6 progenies were karyotyped using C-banding. The aneuploidy frequency was 6.6% with 4.0% hypoploids and 2.6% hyperploids. Among 71 plants with 28 chromosomes, 53.5% had a stabilized karyotype while 46.5% were unstabilized with at least one homoeologous group segregating for A-, B-, or D-genome chromosomes. The stabilized plants represent 19 different tetraploid karyotypes with six of them not containing any detectable D-genome chromosomes from T. aestivum or E-genome chromosome from Th. elongatum. Thirteen lines were (ABD)(ABD)RR tetraploids with one-to-three disomic substitutions of D-genome chromosomes for A or B-genome chromosomes. No disomic substitution of E-genome chromosomes was identified. On average 0.58 D substitutions per line were determined. Of the seven D-genome chromosomes only four, 1D, 2D, 5D, and 7D, were present in their disomic state. In unstabilized karyotypes, chromosomes 3D, 4D, and 6D were present in their monosomic state. Among all 30 viable plants (42.3%), the order of decreasing frequency of Dgenome chromosomes was 5D (25.0%), 1D (20.0%), 2D (10.0%), 6D (5.0%), and 3D (1.7%). Plants with 4D and 7D chromosomes were not viable. An increase in the number of D-genome chromosomes in the (ABD) genome is associated with a decrease in viability and fertility. Minor differences in the C-banding of chromosomes in homoeologous groups 1, 5, and 6 indicate the possibility of translocations between A-, B-, D-, and E-genome chromosomes. Evolutionary and breeding aspects of tetraploid triticale with mixed genomes are discussed.

Introduction of D-genome chromosomes from Aegilops squarrosa L. into tetraploid triticale (AB)(AB)RR (2n=28)

Tetraploid triticale with the genome constitution (ABD) (ABD)RR (2n=4x=28) selected from the progenies of DDRR x (AB)(AB)RR hybrids (D(AB)RR) were karyotyped using C-banding. The aneuploidy frequency was 10.7% with 4.4% hypoploids and 6.3% hyperploids in the F5. Among 67 plants having 28 chromosomes, 41.8% had a stabilized karyotype, while 58.2% were unstabilized with at least one homoeologous group segregating for A-, B- or D-genome chromosomes. The stabilized plants represented ten different karyotypes that contained one to five disome substitutions of D-genome chromosomes for A- or B-genome chromosomes. Two (BD) (BD)RR tetraploids had no A-genome chromosomes. The average number of D substitutions was 3.0 per line. Of the seven substitutions possible only one, 4D(4B), was not present. In the progeny of plants selected for fertility a selection pressure acted against wheat chromosomes 1B, 3B, 4D and 7D. The most favoured chromosome constitution of the (ABD) mixed genome was 1D, 2A, 3D, 4B, 5B, 6A and 7B. Plants of that karyotype but with a heterologous pair of chromosomes 5B and 5D had the best seed set. Evolutionary and breeding aspects of tetraploid triticale are discussed.