Transcriptome-Wide Prediction and Measurement of Combined Effects Induced by Chemical Mixture Exposure in Zebrafish Embryos.

BACKGROUND: Humans and environmental organisms are constantly exposed to complex mixtures of chemicals. Extending our knowledge about the combined effects of chemicals is thus essential for assessing the potential consequences of these exposures. In this context, comprehensive molecular readouts as retrieved by omics techniques are advancing our understanding of the diversity of effects upon chemical exposure. This is especially true for effects induced by chemical concentrations that do not instantaneously lead to mortality, as is commonly the case for environmental exposures. However, omics profiles induced by chemical exposures have rarely been systematically considered in mixture contexts. OBJECTIVES: In this study, we aimed to investigate the predictability of chemical mixture effects on the whole-transcriptome scale. METHODS: We predicted and measured the toxicogenomic effects of a synthetic mixture on zebrafish embryos. The mixture contained the compounds diuron, diclofenac, and naproxen. To predict concentration- and time-resolved whole-transcriptome responses to the mixture exposure, we adopted the mixture concept of concentration addition. Predictions were based on the transcriptome profiles obtained for the individual mixture components in a previous study. Finally, concentration- and time-resolved mixture exposures and subsequent toxicogenomic measurements were performed and the results were compared with the predictions. RESULTS: This comparison of the predictions with the observations showed that the concept of concentration addition provided reasonable estimates for the effects induced by the mixture exposure on the whole transcriptome. Although nonadditive effects were observed only occasionally, combined, that is, multicomponent-driven, effects were found for mixture components with anticipated similar, as well as dissimilar, modes of action. DISCUSSION: Overall, this study demonstrates that using a concentration- and time-resolved approach, the occurrence and size of combined effects of chemicals may be predicted at the whole-transcriptome scale. This allows improving effect assessment of mixture exposures on the molecular scale that might not only be of relevance in terms of risk assessment but also for pharmacological applications. https://doi.org/10.1289/EHP7773.

An ecotoxicological view on neurotoxicity assessment.

The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.

Germline Mutations in RASA1 Are Not Found in Patients with Klippel-Trenaunay Syndrome or Capillary Malformation with Limb Overgrowth.

The RASA1 gene encodes p120RASGAP, a multidomain cytoplasmic protein that acts as a negative regulator of the RAS signalling pathway. Heterozygous loss-of-function RASA1 mutations were identified in patients with Parkes Weber syndrome and multifocal capillary malformations. This syndrome is characterised by a capillary blush on an extremity, arteriovenous microfistulas, and bony and soft tissue hypertrophy. The aim of this study was to test RASA1 in 2 disorders characterised by asymmetric limb enlargement and vascular malformations, namely Klippel-Trenaunay syndrome and regional capillary malformation with overgrowth. We did not identify any clear pathogenic change in these patients. Thus, besides clinical and radiological criteria, RASA1 testing constitutes an additional tool to differentiate Parkes Weber syndrome of capillary malformation-arteriovenous malformation (CM-AVM) from overlapping disorders.

Spatiotemporal regulation of cell-cycle genes by SHORTROOT links patterning and growth.

The development of multicellular organisms relies on the coordinated control of cell divisions leading to proper patterning and growth. The molecular mechanisms underlying pattern formation, particularly the regulation of formative cell divisions, remain poorly understood. In Arabidopsis, formative divisions generating the root ground tissue are controlled by SHORTROOT (SHR) and SCARECROW (SCR). Here we show, using cell-type-specific transcriptional effects of SHR and SCR combined with data from chromatin immunoprecipitation-based microarray experiments, that SHR regulates the spatiotemporal activation of specific genes involved in cell division. Coincident with the onset of a specific formative division, SHR and SCR directly activate a D-type cyclin; furthermore, altering the expression of this cyclin resulted in formative division defects. Our results indicate that proper pattern formation is achieved through transcriptional regulation of specific cell-cycle genes in a cell-type- and developmental-stage-specific context. Taken together, we provide evidence for a direct link between developmental regulators, specific components of the cell-cycle machinery and organ patterning.

Moxifloxacin in acute exacerbations of chronic bronchitis: clinical evaluation and assessment by patients.

The clinical success of a 5-day course of oral moxifloxacin (administered once daily at a dose of 400 mg) was evaluated in 328 patients with acute exacerbations of chronic bronchitis (Anthonisen type 1) in a non-comparative study conducted by chest physicians in private practice. Results were assessed on the basis of clinical parameters and, for the first time in a trial involving oral moxifloxacin, by the surrogate marker of patient satisfaction. Improvement in (and severity of) cough, dyspnoea, chest pain and sputum were scored daily by patients. Cough, chest pain and purulent sputum production improved rapidly within the first 5 days of treatment. At least 90% of patients were satisfied with the antibiotic. The clinical success rate (cure and improvement) for all patients involved (intent-to-treat analysis) was 90.5%. The most commonly experienced adverse events were gastrointestinal related, with diarrhoea the most frequent of these (2.7% of all patients).

Monotherapy with intravenous followed by oral high-dose ciprofloxacin versus combination therapy with ceftazidime plus amikacin as initial empiric therapy for granulocytopenic patients with fever.

The aim of the present study was to obtain clinical experience with the use of high-dose ciprofloxacin as monotherapy for the treatment of febrile neutropenia episodes (granulocyte count, <500/mm(3)) compared to a standard regimen and to clarify whether ciprofloxacin administration may be switched to the oral route. In a prospective randomized study ciprofloxacin was given at 400 mg three times a day (t.i.d.) for at least 72 h followed by oral administration at 750 mg twice a day (b.i.d). That regimen was compared with ceftazidime given intravenously at 2 g t.i.d. plus amikacin given intravenously at 500 mg b.i.d. The frequency of successful clinical response without modification at the end of therapy was almost identical for ciprofloxacin (50% [62 of 124 patients]) compared with that for ceftazidime plus amikacin (50.8% [62 of 122 patients]) in an intent-to-treat analysis; the frequencies were 48.3% (57 of 118 patients) versus 49.6% (56 of 113 patients), respectively, in a per-protocol analysis (P values for one-sided equivalence, 0.0485 and 0.0516, respectively; delta = 10%), with no significant differences among patients with bacteremia and other microbiologically or clinically documented infections and fever of unknown origin. For 82 (66.1%) patients, it was possible to switch from parenteral ciprofloxacin to the oral ciprofloxacin, and the response was successful for 61 (74.4%) patients. The efficacies of the regimens against streptococcal bacteremias were 16.6% (one of six patients) for the ciprofloxacin group and 33.3% (one of three patients) for the combination group (it was not statistically significant), with one breakthrough streptococcal bacteremia observed among the ciprofloxacin-treated patients. Adverse events were mostly self-limited and were observed in 27 (20.6%) ciprofloxacin-treated patients and 26 (19.7%) patients who were receiving the combination. This study demonstrates that high-dose ciprofloxacin given intravenously for at least 3 days and then by the oral route is therapeutically equivalent to the routine regimen of intraveneous ceftazidime plus amikacin even in febrile patients with severe neutropenia (polymorphonuclear leukocyte count, <100 mm(3)). However, it is very important that before an empirical therapy is chosen each hospital determine bacteriologic predominance and perform resistance surveillance.

[Oromaxillofacial surgery in Europe]. / Mund-Kiefer-Gesichts-Chirurgie im europäischen Umfeld.

The recognition of a medical discipline on a European level as an independent specialty depends on its registration in the medical directives of the European Union. With supreme effort, the oral and maxillofacial surgeons of the EU reached this goal in 1989. The UEMS--Section of Stomatology and Oromaxillofacial Surgery--became the forum for discussion of the relevant problems with representatives of the member states and officials of the European Commission. Thanks to its activities, oral and maxillofacial surgery is now recognized as an independent specialty with about 3800 specialists in 11 European countries.

Ciprofloxacin in the treatment of chronic bacterial prostatitis: a prospective, non-comparative multicentre clinical trial with long-term follow-up. The German Prostatitis Study Group.

The efficacy and safety of ciprofloxacin 500 mg bd for 28 days were assessed in 65 adult males with symptomatic bacterial prostatitis, from eight centres in Germany. Urine and prostatic secretions were obtained for culture. Clinical signs and symptoms were evaluated at 12-18 days during treatment, end of treatment (4-9 days post-treatment), and 1, 3, 6 and 9 months post-treatment. Safety was monitored during and at the end of treatment. E. coli was the most frequent pathogen causing infection (35/62) and Enterococcus faecalis the second most frequent (13/62). The combined bacteriological response by patient determined at return visits 4-9 days post and 1 month post-treatment, respectively, was eradication 48/54 (88.9%), persistence 3/54 (5.6%), eradication with recurrence 1/54 (1.9%) and eradication with reinfection 2/54 (3.7%). The clinical response at 1 month post-treatment was resolution 53/54 (98. 1%) and 1/54 (1.9%) failure. The rates for continued eradication in the extended follow-up were 32/39 (82.1%) after 3 months, 26/34 (76. 4%) after 6 months and 13/22 (59.1%) after 9 months. Nineteen patients experienced at least one adverse event. In two patients the trial was prematurely discontinued due to adverse events.

[Moxifloxacin in the treatment of chronic bronchitis--clinical evaluation and assessment by patients]. / Moxifloxacin bei akuter Exazerbation der chronischen Bronchitis. Klinische Bewertung und Beurteilung durch Patienten.

BACKGROUND AND METHOD: The aim of this trial conducted in the offices of pneumologists was to evaluate the clinical success of a 5-day course of oral moxifloxacin administered once daily at a dose of 400 mg in 328 patients with acute exacerbation of chronic bronchitis (Anthonisen type 1). In this non-comparative study, the results of treatment were assessed not merely on the basis of the clinical parameters, but also, for the first time, by the surrogate marker of patient satisfaction and the improvement in cough, dyspnea, chest pain and sputum, the severity of which was scored daily by the patient himself. RESULTS: Cough, chest pain and the purulence of the sputum improved rapidly within the first five days of treatment. At least 90% of the patients reported their satisfaction with the antibiotic. The clinical success rate (cure and improvement) for all the patients involved (ITT analysis) was 90.5%. The most common side effect was diarrhea, while the other side effects showed no specific pattern.

[Behavioral response of cows after intrauterine application of disinfectants for treatment of endometritis]. / Das Verhalten von Kühen nach intrauteriner Applikation von Desinfizienzien zur Behandlung der Endometritis.

Seventy-five animals were investigated in an attempt to study the chronological process of response to vaginal irritation by application of disinfectants for endometritis therapy. Aqueous peracetic acid solutions and Lugol solution were used. Cows reacted to intrauterine application of disinfectant drugs with tail lifting, pressing and sometimes groaning as expression of pain. We tried to quantify this response by registration of these different signs longer than two hours after treatment. The responses are caused by reflux of solution from the uterus into the vagina. They were different and depending on reflux volume, used drugs and their concentration. In comparison to peracetic acid solutions, the application of Lugol with 0.5% iodine seemed to induce a more intensive response to application.

[Experimental studies of the effect of peracetic acid on the endometrium of cattle]. / Experimentelle Untersuchungen zur Wirkung der Peressigsäure auf das Endometrium des Rindes.

Histological investigations were made on uteri of 61 cattle (27 of them after intrauterine treatment). The response activated by 0.2% peracetic acid in the bovine endometrium was a primary inflammatory process, however, necrotising within clearly pronounced limits. Degenerative alterations were the major histological findings 35 minutes from application of 0.2% peracetic acid. They were recordable from the epithelium but at that point in time could easily affect the entire cellular stratum. Histopathological phenomena on the fourth day from application of 0.2% peracetic acid were clearly less strongly pronounced than on the third day. Histiocyte infiltrates of moderate and rarely high intensity reflected increased phagocytosis in the process of endometrial regeneration.

Randomised controlled comparison of single-dose ciprofloxacin and doxycycline for cholera caused by Vibrio cholerae 01 or 0139.

BACKGROUND: Effective antimicrobial therapy can reduce the duration and volume of cholera diarrhoea by half. However, such treatment is currently limited by Vibrio cholerae resistance to the drugs commonly prescribed for cholera, and by the difficulties involved in the administration of multi-drug doses under field conditions. Because of its favourable pharmacokinetics we thought it likely that single-dose ciprofloxacin would be effective in the treatment of cholera. METHODS: In this double-blind study treatment was either a single 1 g oral dose of ciprofloxacin plus doxycycline placebo, or a single 300 mg oral dose of doxycycline plus ciprofloxacine placebo. 130 moderately or severely dehydrated men infected with V cholerae 01 and 130 infected with V cholerae 0139 were randomly assigned treatment. Patients stayed in hospital for 5 days. We measured fluid intake and stool volume every 6 h, and a sample of stool for culture was obtained daily. The primary outcome measures were clinical success--the cessation of watery stool within 48 h; and bacteriological success--absence of V cholerae from cultures of stool after study day 2. FINDINGS: Among patients infected with V cholerae 01, treatment was clinically successful in 62 (94%) of 66 patients who received ciprofloxacin and in 47 (73%) of 64 who receive doxycycline (difference 21% [95% Cl 8-33]); the corresponding proportions with bacteriological success were 63 (95%) and 44 (69%) (27% [14-39]). Among patients infected with V cholerae 0139, treatment was clinically successful in 54 (92%) of 59 patients who received ciprofloxacin and in 65 (92%) of 71 who received doxycycline (< 1% [-9 to 9]), and bacteriologically successful in 58 (98%) and 56 (79%), respectively (19% [9-30]). Total volume of watery stool did not differ significantly between ciprofloxacin-group and doxycycline-group patients infected with either V cholerae 01 or 0139. All but one of the V cholerae 01 and all of the 0139 isolates were susceptible in vitro to doxycycline, whereas 48 (37%) of the V cholerae 01 isolates and none of the 0139 isolates were resistant to tetracycline. Treatment clinically failed in 14 (52%) of 27 doxycycline-treated patients infected with a tetracycline-resistant V cholerae 01 strain, compared with three (8%) of 37 patients infected with a tetracycline-susceptible strain (44% [23-65]). INTERPRETATION: Single-dose ciprofloxacin is effective in the treatment of cholera caused by V cholerae 01 or 0139 and is better than single-dose doxycycline in the eradication of V cholerae from stool. Single-dose ciprofloxacin may also be the preferred treatment in areas where tetracycline-resistant V cholerae are common. In V cholerae, in-vitro doxycycline susceptibilities are not a useful indicator of the in-vivo efficacy of the drug.

[Evaluation of environmental factors on the fertility of heifers]. / Untersuchungen zur Ermittlung von Einflussfaktoren auf die Fruchtbarkeit von Färsen.

The investigations had the aim to find out the environmental influences upon the fertility performance of 8100 heifers in a big heifers farm. The different reproductive parameters were evaluated by the help of biostatistical methods. The evaluation of the different influences showed no effect in the relation of fertility and nutrition and fertility and seasonality. The check up by the help of the regression analysis and the analysis of variance informed about significant influences by the number of animals per group, by the keeping conditions and by the induction of ovulation. The induction of ovulation by GnRH is able to terminize the time of ovulation. Therefore it is possible to concretisize the insemination time followed by an increasing conception rate.

Changes in chromosomal ultrastructure during the cell cycle.

The surface structure of mitotic barley and rye chromosomes was studied by high-resolution scanning electron microscopy. Chromosomes with various degrees of chromatin condensation were prepared from untreated meristematic tissue of root tips. At lower magnifications the highly condensed chromosomes in metaphase and anaphase showed a compact structure with a smooth surface. The condensation starts from the centromeric region and the chromatids are often discernible in the still uncondensed telomeric region. Decondensation begins at the telomeric region during telophase. Parallel arrangement of fibres is a characteristic feature predominately seen in prophase and telophase chromosomes. Chromatin structures that resemble tiles on a roof or braided strands were often observed. Prophase and telophase chromosomes are particularly suitable for further studies of chromatin arrangement and organization in plant chromosomes.

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.

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. 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.

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.

Refined physical mapping of the Sec-1 locus on the satellite of chromosome 1R of rye (Secale cereale).

The Sec-1 locus (ω-secalin) of rye (Secale cereale L.) was mapped in the satellite of the short arm of chromosome 1R using fluorescence in situ hybridization and a genomic probe called pSec2B. Sec-1 is located in the middle of the satellite at the junction of the proximal euchromatic and the distal heterochromatic regions. Double hybridization experiments using rDNA and pSec2B showed that the NOR spans over the secondary constriction of the short arm of chromosome 1R and that there is a clearly visible gap between the NOR and Sec-1. Heterologous hybridization of pSec2B to barley visualized the B-hordein locus on chromosome 1H.