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PubMed2005

Distribution of genetic diversity among disjunct populations of the rare forest understory herb, Trillium reliquum.

We assessed genetic diversity and its distribution in the rare southeastern US forest understory species, Trillium reliquum. In all, 21 loci were polymorphic (PS=95.5%) and the mean number of alleles per polymorphic locus was 3.05. However, genetic diversity was relatively low (Hes=0.120) considering the level of polymorphism observed for this outcrossing species. A relatively high portion of the genetic diversity (29.7%) was distributed among populations. There was no relationship between population size and genetic diversity, and we did not detect significant inbreeding. These results are best explained by the apparent self-incompatibility of this species, its longevity and clonal reproduction. To address questions regarding the history of T. reliquum's rarity, we compared results for T. reliquum with that of its more common and partially sympatric congener, T. cuneatum. Despite shared life history traits and history of land use, we observed significant genetic differences between the two species. Although T. cuneatum contains slightly lower polymorphism (Ps=85%), we detected significantly higher genetic diversity (Hes=0.217); most of its genetic diversity is contained within its populations (GST=0.092). Our results suggest that not only is there little gene flow among extant T. reliquum populations, but that rarity and population isolation in this species is of ancient origins, rather than due to more recent anthropogenic fragmentation following European colonization. The Chattahoochee River was identified as a major barrier to gene exchange.

Cluster Analysis↗

PubMed1963

SYNTHESIS OF MESSENGER-LIKE RIBONUCLEIC ACID AND PROTEIN DURING MEIOSIS IN ISOLATED CELLS OF TRILLIUM ERECTUM.

The synthesis of RNA and protein by cultures of isolated microsporocytes has been demonstrated. The variation in capacities of such cultures to perform syntheses is a function of meiotic stage and parallels the pattern of changes observed for microsporocytes in situ. A principal feature of this pattern is the induction of syntheses during pachytene and diplotene, stages at which the chromosomes are partly contracted. By use of Actinomycin D, chloramphenicol, pulse-labeling with P(32)-phosphate, and nucleotide analyses of RNA digests, part of the RNA synthesized has been shown to correspond to messenger RNA. Analysis of reaction rates and the overlappings of protein and RNA synthesis indicates that the spread of cytological events in Trillium is not purely a function of the low temperature at which it occurs but, presumably, arises from a complement of regulatory devices which govern the periodic onset of reactions within the cells. The main conclusion drawn from the whole of these studies is that the sequence of morphological changes associated with chromosome contraction and movement during meiosis is accompanied by a set of gene transcriptions. Although comparatively few genes are presumed to be active during meiosis, the action of such genes may be essential to a translation of some of the information embodying the meiotic sequence which has been stored in the genome in the course of evolution.

Cell Division↗

PubMed2003

Steroids from the underground parts of Trillium kamtschaticum.

Two 18-norspirostanol glycosides and an 18-norspirostanol, which were new compounds as natural products, have been isolated from the underground parts of Trillium kamtschaticum PALL. along with eight known steroidal glycosides. Their chemical structures were determined on the basis of spectroscopic data.

Magnetic Resonance Spectroscopy↗

PubMedDate not supplied

Antifungal activity of Trillium grandiflorum constituents.

EtOH extracts of the rhizomes and aboveground portion of Trillium grandiflorum showed significant antifungal activity. Bioassay directed fractionation has led to the identification of the active components as the saponin glycosides 1 and 3.

Animals↗

PubMed2001

Spatial population genetic structure in Trillium grandiflorum: the roles of dispersal, mating, history, and selection.

The roles of the various potential ecological and evolutionary causes of spatial population genetic structure (SPGS) cannot in general be inferred from the extant structure alone. However, a stage-specific analysis can provide clues as to the causes of SPGS. We conducted a stage-specific SPGS analysis of a mapped population of about 2000 Trillium grandiflorum (Liliaceae), a long-lived perennial herb. We compared SPGS for juvenile (J), nonreproductive (NR), and reproductive (R) stages. Fisher's exact test showed that genotypes had Hardy-Weinberg frequencies at all loci and stage classes. Allele frequencies did not differ between stages. Bootstrapped 99% confidence intervals (99%CI) indicate that F-statistic values are indistinguishable from zero, (except for a slightly negative FIT for the R stage). Spatial autocorrelation was used to calculate f the average kinship coefficient between individuals within distance intervals. Null hypothesis 99%CIs for f were constructed by repeatedly randomizing genotypic locations. Significant positive fine-scale genetic structure was detected in the R and NR stages, but not in the J stage. This structure was most pronounced in the R stage, and declined by about half in each remaining stage: near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively. For R and NR, the near-neighbor f lies outside the null hypothesis 99%CI, indicating kinship at approximately the level of half-sibs and first cousins, respectively. We also simulated the expected SPGS of juveniles post dispersal, based on measured R-stage SPGS, the mating system, and measured pollen and seed dispersal properties. This provides a null hypothesis expectation (as a 99%CI) for the J-stage correlogram, against which to test the likelihood that post-dispersal events have influenced J-stage SPGS. The actual J correlogram lies within the null hypothesis 99%CI for the shortest distance interval and nearly all other distance intervals indicating that the observed low recruitment, random mating and seed dispersal patterns are sufficient to account for the disappearance of SPSG between the R and the J stages. The observed increase in SPGS between J and R stages has two potential explanations: history and local selection. The observed low total allelic diversity is consistent with a past bottleneck: a possible historical explanation. Only a longitudinal stage-specific study of SPGS structure can distinguish between historical events and local selection as causes of increased structure with increasing life history stage.

Genetics, Population↗

PubMed1966

DNA content of a chromosome of Trillium erectum: effect of cold treatment.

The DNA (Feulgen) contents of a specific cold-treated (3 degrees C) chromosome and of a control (25 degrees C) were measured by means of photographic-plate microdensitometry. Despite marked morphological alterations in the cold-treated B chromosome of Trillium erectum, its DNA content was unchanged from that of the control.

Chromosomes↗

PubMed2000

Trillium biopassive surface: a new biocompatible treatment for extracorporeal circulation circuits.

139 patients undergoing cardiac surgery were included in a prospective, randomized trial. Patients were randomly allocated to receive cardiopulmonary bypass (CPB) with Trillium Biopassive Surface (TBS Group) coated oxygenators or conventional circuits (control group). 112 patients were studied with respect to postoperative biochemical profile; a subgroup of 27 patients was studied with respect to perioperative complement (C3a) activation. Patients in the TBS group demonstrated a significantly lower white blood cell count at the end of the operation (p=0.036) and a significantly higher platelet count the day after the operation (p=0.023) when compared to the control group. C3a was significantly higher (p=0.02) in the TBS group after 30 minutes of CPB, but the C3a increase after protamine administration was significantly less pronounced in the TBS group vs. the control group. Further studies involving platelet and leukocyte activation are required to better elucidate the action of this new coating in the setting of routine CPB.

Biocompatible Materials↗

PubMed1951