FISH results support the close taxonomic interrelationship between M. arborea and M. strasseri. In these tetraploid species, NOR loci have experienced a diploidization event through physical loss of sequences, a cytogenetic feature so far not reported in other species of the genus. The high number of rDNA loci and GISH results support the specific status for the hexaploid M. citrina, and it is suggested that this species is not an autopolyploid derivative of M. arborea or M. strasseri. Further, molecular cytogenetic data do not suggest the hypothesis that M. arborea and M. strasseri were involved in the origin of M. citrina. FISH mapping can be used as an efficient tool to determine the genomic contribution of M. citrina in somatic hybrids with other medic species.

A comparative genetic analysis of 42 clinical Klebsiella pneumoniae isolates, resistant to two or more antibiotics belonging to the broad-spectrum ␤-lactam group, sourced from Sydney, Australia, and three South American countries is presented. The study focuses on the genetic contexts of class 1 integrons, mobilizable genetic elements best known for their role in the rapid evolution of antibiotic resistance among Gram-negative pathogens. It was found that the class 1 integrons in this cohort were located in a number of different genetic contexts with clear regional differences. In Sydney, IS26-associated Tn21-like transposons on IncL/M plasmids contribute greatly to the dispersal of integron-associated multiple-drug-resistant (MDR) loci. In contrast, in the South American countries, Tn1696-like transposons on an IncA/C plasmid(s) appeared to be disseminating a characteristic MDR region. A range of mobile genetic elements is clearly being recruited by clinically important mobile class 1 integrons, and these elements appear to be becoming more common with time. This in turn is driving the evolution of complex and laterally mobile MDR units and may further complicate antibiotic therapy.

Somatic chromosome numbers, conventional karyotype features and idiograms are reported for 27 Limonium species inhabiting the Western Mediterranean basin (Iberian Peninsula and the Balearic Islands). The chromosome numbers of Limonium barceloi (2n = 36), L. ejulabilis (2n = 24), L. inexpectans (2n = 26), L. interjectum (2n = 24), and L. scopulorum (2n = 25) were determined for the first time. In addition, new aneuploid and/or polyploid cytotypes are reported in L. alcudianum (2n = 26), L. bonafei (2n = 26), L. camposanum (2n = 26), L. companyonis (2n = 26), L. dufourii (2n = 26), L. geronense (2n = 36), L. marisolii (2n = 54), L. migjornense (2n = 50), and L. pseudodictyocladon (2n = 16). A group of polyploid species showed karyotypes comprising homologous chromosomes in groups of three (L. antonii-llorensii, L. ejulabilis, L. interjectum, L. virgatum, and L. wiedmanii), four (L. geronense), or six (L. marisolii), which suggests an autopolyploid origin. Other polyploid species were characterized by the presence of two different chromosome sets (x = 8 and x = 9) in the genome. The species L . alcudianum, L. bonafei, L. camposanum, L. companyonis, L. dufourii, L. gibertii, L. girardianum, L. inexpectans, L. leonardi-llorensii, L. magallufianum, L. migjornense, L. minoricense, and L. scopulorum showed various combinations of paired and unpaired x = 8 and x = 9 chromosome sets, suggesting that they are allopolyploids.

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Mitotic chromosome numbers are reported from 35 vascular plant taxa endemic to the Balearic Islands that are poorly known cytogenetically. The chromosome numbers of Chaenorhinum rodriguezii (2 n = 14), Coristospermum huteri (2 n = 22), Carduus ibicensis (2 n = 26), Filago petro-ianii (2 n = 26), Ononis crispa ssp. zschackei (2 n = 30), and Ophrys bertolonii ssp. balearica (2 n = 36) were determined for the first time. New chromosome numbers are reported in Pimpinella bicknellii (2 n = 22), Calamintha rouyana (2 n = 46), Vicia bifoliolata (2 n = 14), and Teucrium asiaticum (2 n = 30). A new diploid cytotype (2 n = 16) was found in Ranunculus paludosus ssp. barceloi , which is restricted to populations from the western Balearics (Eivissa and Formentera), whereas tetraploid plants are known from the eastern Balearics (Mallorca). It is suggested that the tetraploid cytotype arose from the diploid cytotype through autopolyploidy. The idiograms of Coristospermum huteri , Pastinaca lucida , Pimpinella bicknellii , Carduus ibicensis , Helianthemum scopulicolum , Helichrysum crassifolium , Vicia bifoliolata , P aeonia cambessedesii , Helleborus lividus , Ranunculus paludosus ssp. barceloi , and Linaria aeruginea ssp. pruinosa are determined for the first time.

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Anatomy of the vegetative organs of two species of Atriplex (Chenopodiaceae) from Venezuela. In Venezuela, Atriplex is represented by A. cristata and A. oestophora, the latter being endemic; they inhabit coastal areas with high temperatures, high solar radiation and sandy soils with high salt content. This work aimed to provide information to facilitate and clarify these species taxonomic delimitation, throughout the study of the anatomy of their vegetative organs; this may also clarify our understanding of their adaptability to soil and climatic conditions prevailing in areas they inhabit. The plant material was collected from at least three individuals of each species in Punta Taima Taima and Capatárida, Falcon. Segments of roots, located near the neck and towards the apex, apical, middle and basal internodes of stems, were taken; and of leaves, located in the middle portion of plants. This material was fixed in FAA (formaldehyde, acetic acid, 70% ethanol) until processing. Semipermanent and permanent microscope slides were prepared with transverse or longitudinal sections, made using a razor (free-hand) or a rotation microtome, in this latter case, after paraffin embedding; besides, additional plates were mounted with portions of leaf epidermis, obtained by the maceration technique. The sections were stained with aqueous toluidine blue (1%) or safranin-fast-green, and mounted in water-glycerin or in Canada balsam. In order to calculate the vulnerability index, the vessel diameter in the vascular rings of roots, as well as their density, were quantified. Our results revealed structural features in the different organs, that resulted of taxonomic value and allowed the distinction of the species: in the leaf, the presence of aquifer tissue, the number of vascular bundles and their organization in the midrib, and the collenchyma differentiation in this part of the leaf; in the roots, the xylem and phloem arrangement in the growth rings, the nature of conjunctive tissue, and the presence of included phloem in one species. In addition, the species showed typical anatomical features of halophytes and xerophytes, such as: high density of trichomes on leaves and young stems which act as salt secreting glands, abundant sclerenchyma in stems and roots, water storage tissue and Kranz anatomy in leaves, narrow cortical region in young roots, presence of cambial variants in stems and roots, as well as short and narrow xylem vessels. Vulnerability index calculations indicated that both species tend to assure conduction but not the efficiency of the system. Atriplex species have anatomical characters which facilitate their adaptation to the special conditions prevailing in their habitats and that may be used for taxonomic delimitation. Rev. Biol. Trop. 62 (4): 1625-1636. Epub 2014 December 01.

Mitotic chromosome numbers are reported from 16 Hieracium and two Pilosella species from the Iberian Peninsula and the Balearic Islands that are little known cytogenetically. The chromosome numbers of Hieracium aragonense Scheele (2 n = 27, 36), H. compositum Lapeyr. (2 n = 27), H. murcandidum G. Mateo (2 n = 27), H. spathulatum Scheele (2 n = 27), H. segurae Mateo (2 n = 27), H. teruelanum Mateo (2 n = 27), H. valentinum Pau (2 n = 27), Pilosella pseudovahlii (De Retz) Mateo (2 n = 18), and P. tardans (Peter) Sójak (2 n = 36) were determined for the first time. New cytotypes were detected in H. cordifolium Lapeyr. (2 n = 27) and H. loscosianum Scheele (2 n = 36). The karyotype of the studied species was similar in overall morphology and comprised metacentric and submetacentric chromosomes; secondary constrictions (up to two) were detected in the chromosome complements of some species.