Microsympatry in cryptic lowland salamanders (Caudata: Plethodontidae: Bolitoglossa subgenus Nanotriton) from north‐western Honduras: implications for taxonomy and regional biogeography

The taxonomy of the diminutive bolitoglossine salamanders of the subgenus Nanotriton has previously been a source of confusion among specialists. At various times, at least three different species of Nanotriton have been reported to occur in Honduras: Bolitoglossa nympha, B. occidentalis and B. rufescens. Phylogenetic analysis of 16S and cyt b from samples from three localities in Honduras (departments of Yoro, Copán and Cortés) confirms that most populations are assignable to B. nympha. Nine samples collected from a single locality on the northern slope of the Sierra de Omoa, between 120 and 190 m in elevation, were found to represent two distinct taxa: B. nympha and B. rufescens. Field examination of these nine specimens found them to be morphologically indistinguishable, including a lack of maxillary teeth in all specimens. As such, in situ identification of the two species in north‐western Honduras is problematic given the occurrence of the two taxa in microsympatry in at least one locality. The discovery of yet another divergent lineage of B. rufescens highlights the need for a taxonomic reassessment within this species complex.     

Founding Amerindian mitochondrial DNA lineages in ancient Maya from Xcaret, Quintana Roo

Ancient DNA from the bone remains of 25 out of 28 pre-Columbian individuals from the Late Classic-Postclassic Maya site of Xcaret, Quintana Roo, was recovered, and mitochondrial DNA (mtDNA) was amplified by using the polymerase chain reaction. The presence of the four founding Amerindian mtDNA lineages was investigated by restriction analysis and by direct sequencing in selected individuals. The mtDNA lineages A, B, and C were found in this population. Eighty-four percent of the individuals were lineage A, whereas lineages B and C were present at low frequencies, 4% and 8%, respectively. Lineage D was absent from our sample. One individual did not possess any of the four lineages. Six skeletons out of 7 dated from the Late Classic period were haplotype A, whereas 11 skeletons out of 16 dated from the Postclassic period were also haplotype A. The distribution of mtDNA lineages in the Xcaret population contrasts sharply with that found in ancient Maya from Copán, which lack lineages A and B. On the other hand, our results resemble more closely the frequencies of mtDNA lineages found in contemporary Maya from the Yucatán Peninsula and in other Native American contemporary populations of Mesoamerican origin.     

The ethnobotany of Chaya (Cnidoscolus aconitifolius SSP.Aconitifolius breckon): A nutritious Maya Vegetable

Chaya (Cnidoscolus aconitifolius ssp. aconitifolius Breckon) is a domesticated leafy green vegetable of the Maya region of Guatemala, Belize, southeast Mexico and the Yucatán Peninsula, and parts of Honduras. Though relatively unknown outside of this area, evidence suggests that chaya was of significant importance to ancient peoples of the Yucatán Peninsula and perhaps elsewhere within the Maya region. Here we review what little research has been done on this impressive plant, as well as recount our own ethnobotanical investigation into its use as a food plant and medicine, and discuss its botany, nomenclature, and agricultural use. Due to its ease of cultivation, potential productivity, and above all its substantial nutritional value, we propose chaya as a potential crop for areas outside Mesoamerica.

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La Etnobotanica de Chaya (Cnidoscolus aconitifolius ssp.aconitifolius Breckon): Una Verdura Nutritiva Maya

Resumen  La chaya (Cnidoscolus aconitifolius ssp.aconitifolius Breckon) es una verdura domesticada de la región Maya de Guatemala, Belice, el Sureste de México y la península de Yucatán, y partes de Honduras. Aunque es poco conocida afuera de esta región, la evidencia sugiere que la chaya era una planta importante para los antiguos Mayas de la peninsula de Yucatan, y tal vez en otras partes de la región Maya. A continuatión presentamos la poca investigation realizada sobre esta sorprendente planta, a la vez presentamos resultados de nuestra investigatión etnobotánica acerca de su uso como verdura y medicina, y discutimos su botdnica, nomenclatura, y su agricultura. Dada la facilidad de cultivarla, su productividad potential, y sobre todo su alto valor nutritivo, proponemos la chaya como cultivo potential para regiones afuera de Mesoamérica.

     

Morphological events in cultures of mechanically isolated maize mcirospores

Summary In tis androgenic response, maize is considered to be a recalcitrant plant. We used mechanically isolated microspores of maize genotype A18 to establish a responsive microspore culture of maize. Morphological events occurring during the first days of maize androgenesis in a microspore culture were observed and described, and some morphological markers for distinguishing between embryogenic microspores and nonembryogenic microspores were identified. It was found that the enlargement of microspores during the first days in culture and the ‘star-like’ organization of the cytoplasm inside the microspore are connected with reprogramming of the developmental pathway in maize microspores. Some differences were also found in the surface wall architecture of embryogenic microspores. Fertile plants were successfully recovered from microspore-originated structures.     

Endophytic bacterial flora in the stem tissue of a tropical maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) genotype: isolation,identification and enumeration

The genotypic diversity of indigenous bacterial endophytes within stem of tropical maize (Zea mays L.) was determined in field and greenhouse experiments. Strains were isolated from stem tissues of a tropical maize cultivar (PEHM-1) by trituration and surface disinfestation and their population dynamics was determined. Endophytes were found in most of the growing season at populations ranging from 1.36–6.12 × 10⁵ colony-forming units per gram fresh weight (c.f.u./gm fw) of stem. Analysis of these bacterial endophytes using Gas Chromatography—Fatty Acid Methyl Ester (GC-FAME) led to the identification of Bacillus pumilus, B. subtilis, Pseudomonas aeruginosa and P. fluorescens as the relatively more predominant group of bacterial species residing in maize stem. When the maize seedlings grown in a greenhouse were inoculated with these four isolates individually, their population densities decreased (1.6–3.1 × 10⁵ c.f.u./gm fw of stem) as compared to the field-grown maize (1.8–3.8 × 10⁵ c.f.u./gm fw of stem). The highest persistence, however, was recovered in the case of B. subtilis with a population density of 3.1 × 10⁵ c.f.u./gm fw of stem tissue on 28 days after emergence (DAE). This is the first report on population dynamics of bacterial endophytes from tropical maize and the results establish that symptomless populations of bacteria exist in the maize stem.     

A pair of species of Tauschia Schltdl. (Umbelliferae/Apiaceae) from Mexico

Two species of Tauschia—T. spellenbergii from Chihuahua and T. beruloides from Michoacán and México—are described as new.     

Studies in the Capparaceae XXIII: Capparis coimbrana, a new species from Bolivia

Capparis coimbrana, a tree of the Bolivian and adjoining Brazilian subtropical to warm-temperate seasonal dry forests and savannas, is segregated fromC. petiolaris of the Pacific slope of Ecuador and northern Peru by its subcylindrical fruits (vs. spherical), white pulp (vs. yellow), sepals 3–5 mm (vs.1–3 mm), leaves with 13–24 (vs. 8–15) lateral veins per side, and by 1000 km of geographic isolation. The new species has edible fruits, but is not domesticated. The specific epithet celebrates Germán Coimbra S., eminent Bolivian ethnobotanist.

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Resumen   Capparis coimbrana es un árbol del bosque seco y sabanas subtropicales y cálidas de Bolivia y la parte adyacente de Brasil, segregada deCapparis petiolaris, que se encuentra distribuida en la región del Pacífico de Ecuador y norte de Perú, por sus frutos subcilíndricos (vs. esféricos), pulpa blanca (vs. amarilla), sépalos 3–5 mm (vs. 1–3 mm), hojas con 13–24 (vs. 8–15) pares de venas laterales, y aislada geográficamente 1000 km. Esta nueva especie posee frutos comestibles, pero no está domesticada. Su cpíteto específico honra a Germán Coimbra S., eminente etnobotánico boliviano.

     

Genetic transformation of cork oak (Quercus suber L.) for herbicide resistance

The bar gene was introduced into the cork oak genome. Cork oak embryogenic masses were transformed using the Agrobacterium strain AGL1 which carried the plasmid pBINUbiBar. This vector harbours the genes, nptII and bar, the latter under control of the maize ubiquitin promoter. The transgenic embryogenic lines were cryopreserved. Varying activities of phosphinothricin acetyl transferase were detected among the lines, which carried 1–4 copies of the insert. Molecular and biochemical assays confirmed the stability and expression of the transgenes 3 months after thawing the cultures. These results demonstrate genetic engineering of herbicide tolerance in Quercus spp. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Rubén álvarez, Ricardo J. Ordás are contributed equally.     

Cytological and molecular characterization of oat x maize partial hybrids

In cereals, interspecific and intergeneric hybridizations (wide crosses) which yield karyotypically stable hybrid plants have been used as starting points to widen the genetic base of a crop and to construct stocks for genetic analysis. Also, uniparental genome elimination in karyotypically unstable hybrids has been utilized for cereal haploid production. We have crossed hexaploid oat (2n=6x=42, Avena sativa L.) and maize (2n=2x=20, Zea mays L.) and recovered 90 progenies through embryo rescue. Fifty-two plants (58%) produced from oatxmaize hybridization were oat haploids (2n=3x=21) following maize chromosome elimination. Twenty-eight plants (31%) were found to be stable partial hybrids with 1–4 maize chromosomes in addition to a haploid set of 21 oat chromosomes (2n=21+1 to 2n=21+4). Ten of the ninety plants produced were found to be apparent chromosomal chimeras, where some tissues in a given plant contained maize chromosomes while other tissues did not, or else different tissues contained a different number of maize chromosomes. DNA restriction fragment length polymorphisms (RFLPs) were used to identify the maize chromosome(s) present in the various oat-maize progenies. Maize chromosomes 2, 3, 4, 5, 6, 7, 8, and 9 were detected in partial hybrids and chromosomal chimeras. Maize chromosomes 1 and 10 were not detected in the plants analyzed to-date. Furthermore, partial self-fertility, which is common in oat haploids, was also observed in some oat-maize hybrids. Upon selfing, partial hybrids with one or two maize chromosomes showed nearly complete transmission of the maize chromosome to give self-fertile maize-chromosome-addition oat plants. Fertile lines were recovered that contained an added maize chromosome or chromosome pair representing six of the ten maize chromosomes. Four independently derived disomic maize chromosome addition lines contained chromosome 4, one line carried chromosome 7, two lines had chromosome 9, one had chromosome 2, and one had chromosome 3. One maize chromosome-8 monosomic addition line was also identified. We also identified a double disomic addition line containing both maize chromosomes 4 and 7. This constitutes the first report of the production of karyotypically stable partial hybrids involving highly unrelated species from two subfamilies of the Gramineae (Pooideae — oat, and Panicoideae — maize) and the subsequent recovery of fertile oat-maize chromosome addition lines. These represent novel material for gene/ marker mapping, maize chromosome manipulation, the study of maize gene expression in oat, and the transfer of maize DNA, genes, or active transposons to oat.Joint contribution of the Minnesota Agricultural Experiment Station and USDA-ARS. Scientific journal series paper No. 21 859 of the Minnesota Agricultural Experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the USDA-ARS or the University of Minnesota and does not imply approval over other products that also may be suitable     

Genetic and morphometric differentiation among island populations of two Norops lizards (Reptilia: Sauria: Polychrotidae) on independently colonized islands of the Islas de Bahia (Honduras)

Aim Anole lizards (Reptilia: Sauria: Polychrotidae) display remarkable morphological and genetic differentiation between island populations. Morphological differences between islands are probably due to both adaptive (e.g. differential resource exploitation and intra‐ or interspecific competition) and non‐adaptive differentiation in allopatry. Anoles are well known for their extreme diversity and rapid adaptive speciation on islands. The main aim of this study was to use tests of morphological and genetic differentiation to investigate the population structure and colonization history of islands of the Islas de Bahia, off the coast of Honduras. Location Five populations of Norops bicaorum and Norops lemurinus were sampled, four from islands of the Islas de Bahia and one from the mainland of Honduras. Methods Body size and weight differentiation were measured in order to test for significant differences between sexes and populations. In addition, individuals were genotyped using the amplified fragment length polymorphism technique. Bayesian model‐based and assignment/exclusion methods were used to study genetic differentiation between island and mainland populations and to test colonization hypotheses. Results Assignment tests suggested migration from the mainland to the Cayos Cochinos, and from there independently to both Utila and Roatán, whereas migration between Utila and Roatán was lacking. Migration from the mainland to Utila was inferred, but was much less frequent. Morphologically, individuals from Utila appeared to be significantly different in comparison with all other localities. Significant differentiation between males of Roatán and the mainland was found in body size, whereas no significant difference was detected between the mainland and the Cayos Cochinos. Main conclusions Significant genetic and morphological differentiation was found among populations. A stepping‐stone model for colonization, in combination with an independent migration to Utila and Roatán, was suggested by assignment tests and was compatible with the observed morphological differentiation.     

Astragalus mario-sousae (Fabaceae: Galegeae), a new species from northeastern Mexico

Astragalus mario-sousae is described from the central part of state of Nuevo León, Mexico. It differs fromAstragalus esperanzae by its habit, peduncles, pedicels, and fruits.

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Resumen   Astragalus mario-sousae (Fabaceae: Galegeae), a new species from northeastern Mexico. Brittonia 57: 314–319. 2005.—Astragalus mario-sousae es propuesta como especie nueva. Se conoce solo de la porción central del estado mexicano de Nuevo León. Se presentan una descripción e ilustración. Difiere deAstragalus esperanzae por su hábito erecto, pedúnculos, pedicelos y frutos más cortos.

     

Effect of maize plants on colonisation of cowpea plants by bean flower thrips,Megalurothrips sjostedti

The effect of non-host maize plants on colonisation of cowpea byMegalurothrips sjostedti (Trybom) (Thysanoptera; Thripidae) was investigated. There were no differences in population density and activity ofM. sjostedti on sole cowpea crop and mixed cowpea/maize crop during the colonisation phase (i.e. 10–30 days after emergence of the plants. However, subsequentlyM. sjostedti numbers were lower in the mixed than in the sole crop, suggesting that maize did not interfere with colonisation of cowpea crop by thrips. In a choice situation, higher numbers ofM. sjostedti oriented towards, and settled on, sole cowpea plants than on those mixed with maize. Olfactory tests indicated that fewer thrips oriented towards a cowpea/maize mixed odour source. When equal numbers of thrips were introduced into the centre of sole- and mixed-cropped cowpea plots, the thrips became randomly distributed in each plot. Fewer thrips were recovered from the mixture than from the sole crop. It is concluded that, although non-host plant odours do not reduce thrips colonisation they interfere with host plant utilisation.     

Taxonomic status of the hominid mandible KNM-ER TI 13150 from the middle pliocene of tabarin,in Kenya

A partial mandible with two molars intact was recovered between 1981 and 1984 from deposits of the Middle Pliocene at Tabarin, in Kenya. It has been described and assigned toAustralopithecus cf.afarensis Johanson, White, andCoppens, 1978, with the condition that if ‘A. afarensis’ is revised, then the attribution may change. The taxon ‘A. afarensis’ was found to be invalid and was revised. The smaller specimens of ‘A. afarensis,’ to which the Tabarin mandible was said to be similar, were redescribed asHomo antiquus Ferguson, 1984. Since the Tabarin mandible andH. antiquus are successive transients of the same gens and are allopatric, the Tabarin hominid population is described as an earlier chronosubspecies,Homo antiquus praegens ssp. n.     

Crossing maize with sorghum,Tripsacum and millet: the products and their level of development following pollination

Summary Maize was crossed with sorghum, Tripsacum and millet with the aim of introgressing desirable alien characteristics into maize. The products of crosses were analyzed as to their level of differentiation following pollination; their further development on artificial culture medium was compared. In spite of a stimulation rate close to 5%, no evidence of hybridization between maize and sorghum or millet could be obtained. The plants recovered proved to be of maternal origin. However, with an appreciable frequency, stimulation leading to hypertrophic growth of nucellar tissue was observed. This phenomenon is bound to pollination, never occurring in non-pollinated ears. In crosses involving Tripsacum, more than 140 true hybrids were isolated. The influence of the genotypes used as well as factors such as climatic conditions or in vitro techniques are discussed. Except for one haploid maize plant, all the plants recovered proved to be classical hybrids, most of them showing the expected complement of chromosomes from each parent (10 + 36 chromosomes), a few others being slightly hyperploid (2n = 47 to 50 chromosomes). No non-classical hybrids constituted by a nonreduced female gamete and a reduced male gamete were obtained.     

Improved Agrobacterium-mediated transformation of three maize inbred lines using MS salts

Transformation technology as a research or breeding tool to improve maize is routinely used in most industrial and some specialized public laboratories. However, transformation of many inbred lines remains a challenging task, especially when using Agrobacterium tumefaciens as the delivery method. Here we report success in generating transgenic plants and progeny from three maize inbred lines using an Agrobacterium-mediated standard binary vector system to target maize immature embryos. Eleven maize inbred lines were pre-screened for transformation frequency using N6 salts. A subset of three maize inbred lines was then systematically evaluated for frequency of post-infection embryogenic callus induction and transformation on four media regimes: N6 or MS salts in each of two distinct media backgrounds. Transgenic plants recovered from inbred lines B104, B114, and Ky21 were analyzed for transgene integration, expression, and transmission. Average transformation frequencies of 6.4% (for B104), 2.8% (for B114), and 8% (for Ky21) were achieved using MS salts. Availability of Agrobacterium-mediated maize inbred line transformation will improve future opportunities for maize genetic and functional genomic studies.     

Molecular analysis of crosses between Tripsacum dactyloides and Zea diploperennis (Poaceae)

 DNA fingerprinting verified hybrid plants obtained by crossing Eastern gamagrass, Tripsacum dactyloides L., and perennial teosinte, Zea diploperennis Iltis, Doebley & R. Guzmán. Pistillate inflorescences on these hybrids exhibit characteristics intermediate to the key morphological traits that differentiate domesticated maize from its wild relatives: (1) a pair of female spikelets in each cupule; (2) exposed kernels not completely covered by the cupule and outer glumes; (3) a rigid, non-shattering rachis; (4) a polystichous ear. RFLP analysis was employed to investigate the possibility that traits of domesticated maize were derived from hybridization between perennial teosinte and Tripsacum. Southern blots of restriction digested genomic DNA of parent plants, F₁, and F₂ progeny from two different crosses were probed with RFLP markers specifically associated with changes in pistillate inflorescence architecture that signal maize domestication. Pairwise analysis of restriction patterns showed traits considered missing links in the origin of maize correlate with alleles derived from Tripsacum, and the same alleles are stably inherited in second generation progeny from crosses between Tripsacum and perennial teosinte. Received: 11 October 1996/Accepted:8 November 1996     

Kármán vortex street detection by the lateral line

Fish use the lateral line system for prey detection, predator avoidance, schooling behavior, intraspecific communication and spatial orientation. In addition the lateral line may be important for station holding and for the detection of the hydrodynamic trails (vortex streets) generated by swimming fish. We investigated the responses of anterior lateral line nerve fibers of goldfish, Carassius auratus, to unidirectional water flow (10 cm s⁻¹) and to running water that contained a Kármán vortex street. Compared to still water conditions, both unidirectional water flow and Kármán vortex streets caused a similar increase in the discharge rate of anterior lateral line nerve fibers. If exposed to a Kármán vortex street, the amplitude of spike train frequency spectra increased at the vortex shedding frequency. This increase was especially pronounced if the fish intercepted the edge of a Kármán vortex street. Our data show that the vortex shedding frequency can be retrieved from the responses of anterior lateral line nerve fibers.     

Chromosome polymorphism of teosinte

Florida teosinte from Honduras and Guanajuato teosinte have most of their knobs internally located and a common inversion in the short arm of chromosome 8. Teosintes from northern Guatemala, Huixta and Monajil, have all their knobs terminally located and do not have any inversions. Therefore, Florida teosinte from Honduras appears to be phylogenetically closer to Guanajuato teosinte than it is to Guatemalan teosintes.——The presence of B chromosomes and an In 8 in Guanajuato teosinte and Florida teosinte from Honduras may constitute evidence of introgression between maize and teosinte.     

Purification and characterization of proteolytic enzymes from normal and opaque-2Zea mays L. developing endosperms

Purification and characterization of proteases from developing normal maize endosperm and high lysine opaque-2 maize endosperm have been carried out with a view to understand their role in storage protein modification. At day 15, normal maize endosperm had two types of proteolytic enzymes, namely, protease I and protease II, while at day 25 protease n disappeared and in place protease III appeared. However, in opaque-2 maize endosperm at both the stages only one type of enzyme (protease I) was present. These proteases had many properties in common-optimum pH and temperature were respectively, 5.7and 40°C; their activity was inhibited to the extent of 75 –93 % by p-chloromercuribenzoate; trypsin inhibitor inhibited the activity more at early stages of endosperm development; all proteases cleaved synthetic substrates p-tosyl-L-arginine methylesler and N-benzoyl-L-tyrosine ethyl ester and poly-L-glutamic acid. TheKm values of day 15 and 25 normal maize endosperm proteases ranged from 2.73–3.30, while for opaque-2 maize endosperm protease I it was 3.33 mg azocasein per ml assay medium. These enzymes, however, differed with respect to proteolytic activity towards poly-L-lysine. Only normal maize endosperm protease III at day 25 followed by protease II at day 15 showed high activity towards this homopolypeptide suggesting thereby their role in determining the quality of normal maize endosperm protein. Part of Ph.D. thesis submitted by the first author