The generic placement of a morphologically enigmatic species in Asteraceae: evidence from ITS sequences

 Bidens cordylocarpa is a high polyploid species restricted in distribution to stream sides in the mountains of Jalisco, Mexico. The morphologically enigmatic species was originally described as a member of the genus Coreopsis, but later transferred to Bidens, largely because the involucral bracts appear most similar to Bidens. Characters of the cypselae, often useful in generic placement, are of no value for this species because the fruits have features not detected in either Bidens or Coreopsis. Sequences from the internal transcribed spacer region of nuclear ribosomal DNA (ITS) were used to assess the relationships of Bidens cordylocarpa. The molecular phylogeny places B. cordylocarpa in a strongly supported clade of Mexican and South American Bidens, and provides more definitive evidence of relationships than morphology, chromosome number, or secondary chemistry. Molecular, morphological, and chromosomal data suggest that B. cordylocarpa is an ancient polyploid, perhaps the remnant of a polyploid complex. Received August 28, 2000 Accepted February 11, 2001     

Evolution of the genome size inAkodon (Rodentia,Cricetidae)

Nuclear DNA contents were estimated by microdensitometry in five species of Akodon rodents: Arodon molinae, A. dolores, A. mollis, A. azarae, Bolomys obscurus) and in three chromosomal varieties of A. molinae (2n = 42; 2n = 43, 2n = 22). The data obtained showed that the species with the highest DNA content was B. obscurus, followed in order of decreasing genome size by A. molinae, A. mollis, A. dolores and A. azarae. In A. molinae the forms with 2n = 42 chromosomes had the lowest and the forms with 2n = 44 the highest amount of DNA, while the forms with 2n = 43 had intermediate DNA contents. The variation in DNA amount detected in A. molinae was interpreted as a phenomenon of amplification occurring in the chromosomal areas involved in the chromosomal rearrangement giving rise to the polymorphism exhibited by this species. The DNA contents of shared chromosomes (chromosomes with similar size, morphology and G banding pattern, which are found in two or more phylogenetically related species), were compared and correlated with values of total nuclear DNA. The information obtained indicates that: (a) shared chromosomes have variable amounts of DNA: (b) in a given species there is a correlation between the amount of nuclear and chromosomal DNA in most shared chromosomes (and perhaps in most of the chromosomal complement), e.g., the higher the amount of nuclear DNA, the higher the content of DNA in shared chromosomes; (c) some chromosomes may undergo processes of amplification or deletion restricted to certain regions and usually related with mechanisms of chromosomal rearrangements.(ABSTRACT TRUNCATED AT 250 WORDS)     

A systematic study of the Vernonia leopoldi complex (Compositae — Vernonieae)

A systematic study of the Vernonia leopoldi complex was undertaken with the objective of determining the taxonomic status of the species involved within this group. TWo species, i.e. Vernonia leopoldi and V. bipontini have been recognized as distinct based on evidence from morphological studies accompanied by field observations and anatomical studies (particularly trichomes and petioles). Both species have 2n = 36 (first reports). Three new varieties have been recognized within V. bipontini , namely var. bipontini , var. gonderensis and var. caccaensis . A lectotype is selected for V. leopoldi .     

Comparative capitular morphology and anatomy of Coreopsis L. and bidens L. (compositae), including a review of generic boundaries

The capitular and floral morphology and anatomy ofBidens L. andCoreopsis L. were studied. All the North American species ofCoreopsis were studied. Selected species ofBidens from North and South America andCoreopsis from South America were included. The results were compared with previous observations on African species ofBidens (incl.Coreopsis). Emphasis was given to character states of the ray florets, paleae, stylearm apices, outer phyllaries, achenes, and pollen grains. Some of the character states are unique features ofCoreopsis, e.g., globular and elongately conical receptacles, deltoid outer phyllaries, truncate and indistinctly 3–5-dentate, 3–4-lobed ray florets, narrowly spathulate paleae, subulate paleae with linear-filiform upper half, hairy and apically 3-cleft paleae, truncate, convex or shallowly conical stylearm apices with the sweeping hairs limited to the area above the stigmatic surfaces and the orbicular to circular achenes. The cylindric setaceous pappus bristles so commonly encountered inBidens are unknown inCoreopsis. The pappus bristles inCoreopsis are paleaceous but similar, though thicker ones are also found in African species ofBidens (incl.Coreopsis) with winged achenes. Twin-celled hairs (setulae) with differing degrees of wall thickness are found on the achenes ofCoreopsis sect.Pseudoagarista (Mexico and South America),Coreopsis sect.Pugiopappus (California), AfricanBidens with winged achenes (e.g.,B. prestinaria, B. macroptera) and some North AmericanBidens (e.g.,B. aristosa). Similar sclerotic parenchyma make up the achenial wings of species in both genera. These may be interpreted as homologous structures, indicating the underlying similarity of these taxa and their derivation from a common ancestral stock.     

The life cycle of Eimeria falciformis var. pragensis (Sporozoa: Coccidia) in the mouse, Mus musculus

The life cycle of Eimeria falciformis var. pragensis, established from a single oocyst, is described in experimentally infected mice (Mus musculus). The coccidium had a prepatent period of 7 days and a patent period of 10--16 days. Oocysts were spherical to ellipsoidal in shape and measured 21.2 x 18.3 micron. Sporulation time was 3 to 3.5 days. Sporocysts measured 12.2 x 7.2 micron and contained a circular to avoid granular sporocyst residuum measuring 5.5 X 5.0 micron. One, 2 or 3 circular to rectangular polar granules were observed within each sporulated oocyst. The endogenous stages developed primarily in the cecum and colon and only occasionally in the lower ileum. Four generations of schizonts were found. Mature 1st-generation schizonts, first observed 48 hr postinfection (PI), measured 17.8 x 12.3 micron and had 12 merozoites that measured 13.3 x 2.0 micron. Mature 2nd-generation schizonts appeared 78 hr PI. They measured 10.2 x 9.3 micron and had 8 merozoites measuring 5.0 x 1.6 micron. Mature 3rd-generation schizonts appeared first at 114 hr PI and measured 17.5 x 10.2 micron and had 10 merozoites that measured 12.4 x 1.8 micron. Mature 4th-generation schizonts appeared first at 144 hr PI. They measured 18.2 x 15.3 micron and had 18 merozoites. The merozoites of the 4th-generation schizont were 4.5 x 1.2 micron. Mature macrogamonts and microgamonts developed simultaneously appearing at 156 hr PI. Macrogamonts measured 16 x 14.5 micron and microgamonts were 18.2 x 15.3 micron. In experimentally infected rats (Rattus norvegicus), development of E. falciformis var. pragensis progressed only as far as mature 1st-generation schizonts.     

Robertsonian karyotype variation in wild house mice from Rhaeto-Lombardia

The European longtailed house mouse (M. m. brevirostris and domesticus) in the Rhaetian Alps and Lombardia presents a complex system of Robertsonian (Rb) variation and karyotype diversity, several adjoining populations homozygous for multiple Rb metacentric chromosomes, sites of coexistence of different Rb types, and zones of hybridization with non-Rb populations. The original "tobacco mouse" is just one of many local Rb variants, such as those from other Alpine areas (e.g., Orobian Alps) or from Central Lombardia, where a relatively large region within which the population is homogeneous for multi-Rb metacentrics is found. The present study is based strictly on material in which the chromosome arms were identified by G-banding, so that karyotypes within the areas under investigation could be compared. Altogether 111 mice were studied.     

Bidens burundiensis, a new species of Bidens (Compositae–Heliantheae) from Burundi

Bidens burundiensis M. Tadesse, a new species of Bidens L. belonging to the tribe Heliantheae O. Hoffm., subtribe Coreopsidinae Less is described from the highlands of Burundi.     

The analysis of chromatin organisation allows selection of mouse antral oocytes competent for development to blastocyst

Mouse antral oocytes can be classified in two different types termed SN or NSN oocytes, depending on the presence or absence, respectively, of a ring of Hoechst 33342-positive chromatin surrounding the nucleolus. The aim of the present study was to test the developmental competence to blastocyst of the two types of oocytes. Here we show that following isolation, classification and culture of cumulus-free antral oocytes, 14.7% and 74.5% of NSN and SN oocytes, respectively, reached the metaphase II stage. When fertilised and further cultured none of the metaphase II NSN oocytes developed beyond the 2-cell stage whilst 47.4% of the metaphase II SN oocytes reached the 4-cell stage and 18.4% developed to blastocyst. The findings reported in this paper may contribute to improved procedures of female gamete selection for in vitro fertilisation of humans and farm animals. Furthermore, the selection of oocytes with better developmental potential may be of interest for studies on nuclear/cytoplasm interaction, particularly in nuclear-transfer experiments.     

Reproductive and Developmental Toxicity of Orally Administered Botanical Composition,UP446‐Part III: Effects on Fertility and Early Embryonic Development to Implantation in Sprague Dawley Rats

In recent years, high prevalence of adverse effects associated to the use of traditional medicines during pregnancy is becoming alarming due to the self‐medication of oral supplements by expecting mothers without supervision. Many expectant mothers use alternative and complementary medicines as a supplement to conventional pregnancy management with an inherent belief of considering herbal remedies as harmless. To the contrary, herbal remedies could incur a potential teratogenic risk both to the child bearing mother and the developing fetuses when consumed before or at the time of gestation. Here, we describe the potential adverse effects of orally administered UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, on fertility and early embryonic development to implantation in Sprague Dawley rats at doses of 250, 500, and 1000 mg/kg. Besides body weight and food consumption, reproductive functions, sperm motility and morphology, estrus cycle, and fertility rate were monitored. There were no statistically significant differences in reproductive function in all UP446 treated groups in both genders. Test substance impacts on reproductive parameters were very minimal. Neither sperm motility nor morphology was affected as a result of oral UP446 administrations in males. There were no treatment‐related effects on estrus cycle stages in females. No significant changes in necropsy or histopathology were observed for all the groups. Therefore, the no observed adverse effect level (NOAEL) of UP446 was considered to be 1000 mg/kg, the highest dose tested, in both genders