Shoot histogenesis in tobacco callus cultures

Summary The earliest histological event observed in light-grown shoot-forming tobacco (Nicotiana tabacum L. cv. Wisconsin 38) callus was the deposition of safranin-stainable substances (probably suberin) on cut, exposed cell surfaces. This was followed by the initiation of cell files and the appearance of starch granules. Nodules with lignified tracheary elements also were observed in the upper part of the callus. Pronounced starch accumulation occurred in the lower part of the callus in which protrusions of tissue into the medium occurred. Meristemoids were found in these protrusions as well as elsewhere. In between meristemoids, parenchyma cells with starch granules of varying sizes were observed. Cell strands that connected with the meristemoids also were observed. These strands often terminated at the surface of the protrusion at which point shoot apices originated. The earliest shoots were formed in these protrusions. With time, additiional shoots were formed in other parts of the bottom of the callus and finally in the top part of the callus on prolonged culture. The determination of the loci at which shoot primordia were formed sequentially, was interpreted in relation to the physiological gradient concept. This work was carried out while E. M. was a Visiting Scientist at the University of Calgary under the Scientific Exchange Program between the National Research Council of Canada and the Japan Society for the Promotion of Science. Support for this study was provided by N.R.C. (Canada) Grant A-6467 to T. A. T.     

Ureide biogenesis and the enzymes of ammonia assimilation and ureide biosynthesis in nitrogen fixing pigeonpea (Cajanus cajan) nodules

Allantoic acid production from IMP, XMP, inosine, xanthosine, hypoxanthine, xanthine, uric acid and allantoin was investigated by incubating each of these substrates withCajanus cajan cytosol and bacteroid fractions separately in the presence and absence of NAD+ and allopurinol. Allantoic acid synthesis by bacteroid fraction could only be observed with uric acid and allantoin as substrates. Addition of NAD⁺ or allopurinol to the reaction mixtures had no effect. However, with cytosol fraction, allantoic acid was produced by each of these substrates, with maximum rate with allantoin. With NAD⁺ or with allopurinol, allantoic acid was produced only with uric acid and allantoin as substrates. NADH production with cytosol fraction could again be observed with all the substrates. Except with uric acid and allantoin, allopurinol completely inhibited NADH formation. Regardless of the presence or absence of allopurinol, none of the substrates exhibited significant activity with bacteroid fraction. Based on the activities of glutamine synthetase, glutamate synthase, glutamate dehydrogenase, aspartate aminotransferase, asparagine synthetase, nucleotidase, nucleosidase, xanthine de-hydrogenase, uricase and allantoinase and their intracellular localisation in various nodule fractions, a probable pathway for the biogenesis of ureides in pigeonpea nodules has been proposed     

Nodule bacteria from the cultured legume Phaseolus dumosus (belonging to the Phaseolus vulgaris cross-inoculation group) with common tropici phenotypic characteristics and symbiovar but distinctive phylogenomic position and chromid

Phaseolus dumosus is an endemic species from mountain tops in Mexico that was found in traditional agriculture areas in Veracruz, Mexico. P. dumosus plants were identified by ITS sequences and their nodules were collected from agricultural fields or from trap plant experiments in the laboratory. Bacteria from P. dumosus nodules were identified as belonging to the phaseoli-etli-leguminosarum (PEL) or to the tropici group by 16S rRNA gene sequences. We obtained complete closed genomes from two P. dumosus isolates CCGE531 and CCGE532 that were phylogenetically placed within the tropici group but with a distinctive phylogenomic position and low average nucleotide identity (ANI). CCGE531 and CCGE532 had common phenotypic characteristics with tropici type B rhizobial symbionts. Genome synteny analysis and ANI showed that P. dumosus isolates had different chromids and our analysis suggests that chromids have independently evolved in different lineages of the Rhizobium genus. Finally, we considered that P. dumosus and Phaseolus vulgaris plants belong to the same cross-inoculation group since they have conserved symbiotic affinites for rhizobia.     

Agreement Between American and European Thyroid Imaging,Reporting, and Data System (TIRADS) in the Diagnosis of 473 Thyroid Nodules From a Single Center in Brazil

ObjectiveTo compare 2 ultrasound-based risk stratification systems in malignancy risk assessment of thyroid nodules and the clinical applicability of these guidelines in Brazil.MethodsWe retrospectively reviewed the ultrasound findings of 314 patients (473 thyroid nodules) who underwent fine-needle aspiration (FNA) biopsy and/or surgery between February 2018 and March 2019. All nodules were classified using 2 systems: the Thyroid Imaging, Reporting, and Data System (TIRADS) of the American College of Radiology (ACR-TIRADS) and the TIRADS of the European Thyroid Association (EU-TIRADS). Both risk stratification systems were analyzed. We identified the diagnostic predictive values that yielded optimal sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.ResultsOf the 473 nodules, all underwent FNA, and histopathology was performed for 332 nodules. The agreement between the ACR-TIRADS and EU-TIRADS results and that between cytology and histopathology findings was 92.6% (kappa = 0.84) and 86.7% (kappa = 0.73), respectively. The area under the curve for the ACR-TIRADS and EU-TIRADS was 0.871 and 0.828, respectively (P < .001). The EU-TIRADS had the best sensitivity and negative predictive value, whereas the ACR-TIRADS had the best specificity, positive predictive value, and accuracy. Of the 473 nodules studied, only 158 (33.4%) followed the FNA size criteria suggested by the ACR-TIRADS.ConclusionACR-TIRADS and EU-TIRADS had good diagnostic performances. However, most aspirated nodules did not follow the TIRADS indication; thus, the overuse of FNA as a diagnostic tool was observed.     

A possible case of melorheostosis from antiquity

An unusual case of discontinuous hard tissue hyperostosis is described in a 25-30–year-old female dating between 4000 and 5500 BP from northern Chile. This specimen was one of 104 individuals examined from the Morro-1 site, which is known to represent the Chinchorro culture. The only other reported case from antiquity dates to 500 AD (Lester [1969] J. Bone Joint Surg. [Am.] 49:142–143). A review and comparison of this case to the medical literature supports a diagnosis of melorheostosis. Differential diagnosis is presented with the ruling out of nonspecific manifestations of osteomyelitis/periostitis as the most likely alternative diagnosis. © 1995 Wiley-Liss, Inc.     

Update on: proteome analysis in thyroid pathology – part II: overview of technical and clinical enhancement of proteomic investigation of the thyroid lesions

ABSTRACT

Introduction: An accurate diagnostic classification of thyroid lesions remains an important clinical aspect that needs to be addressed in order to avoid ‘diagnostic’ thyroidectomies. Among the several ‘omics’ techniques, proteomics is playing a pivotal role in the search for diagnostic markers. In recent years, different approaches have been used, taking advantage of the technical improvements related to mass spectrometry that have occurred.

Areas covered: The review provides an update of the recent findings in diagnostic classification, in genetic definition and in the investigation of thyroid lesions based on different proteomics approaches and on different type of specimens: cytological, surgical and biofluid samples. A brief section will discuss how these findings can be integrated with those obtained by metabolomics investigations.

Expert commentary: Among the several proteomics approaches able to deepen our knowledge of the molecular alterations of the different thyroid lesions, MALDI-MSI is strongly emerging above all. In fact, MS-imaging has also been demonstrated to be capable of distinguishing thyroid lesions, based on their different molecular signatures, using cytological specimens. The possibility to use the material obtained by the fine needle aspiration makes MALDI-MSI a highly promising technology that could be implemented into the clinical and pathological units.     

Effect of substrate nitrogen on the performance ofin vitro propagatedAlnus glutinosa clones inoculated with Sp+ and Sp− Frankia strains

The addition of combined nitrogen to substrate at an appropriate rate can stimulate N₂-fixation thus inreasing the efficiency of the Alnus-Frankia symbiosis. To examine how nitrogen additions can effect the peformance of different pairs of symbionts, growth and time course of N₂-fixation were studied in plants supplied with NH₄NO₃. Two cloned ofAlnus glutinosa (L.) Gaertn., propagatedin vitro, were inoculated with two strains ofFrankia (AVP3d and ACN14a) and grown in a greenhouse. Calcined montmorillonite (Totfaice^R) was used as growth substrate. Six N treatments were made up of varied amounts of NH₄NO₃ supplied in one single addition shortly before inoculation. Weekly measurements of shoot height and repeated measurements of nitrogenase activity (acetylene reduction) performed on intact root systems were used to monitor the development of the symbioses. Nitrogen treatments containing from 0.10 to 0.68 mg N g⁻¹ dry substrate stimulated N₂-fixation as well as growth. The relative performance of the two clones was different according to N treatment; one clone showed a greater benefit from the nitrogen input. Our results support the recommendation that selection of symbionts according to performance should be carried out with an input of combined nitrogen. This can provide optimum conditions for the development of each pair of symbionts.     

Epithelial cell line and subline established from premalignant mouse mammary tissue

Summary A cell line and subline with epithelial characteristics were established from mouse mammary hyperplastic alveolar nodules (HAN). The cells do not grow in suspension cultures in vitro or form tumors in vivo. The cells do produce significant amounts of C-type and A-type virus and low amounts of plasminogen activator. This work was supported by ACS Postdoctoral Fellowship PF-1473, and Grant 5-ROI-CA-16392-05 and Contract NO1-CB-63986 from the National Institutes of Health.