The intersectional hybrid between Weigela hortensis and W. maximowiczii (Caprifoliaceae)

Morphologically intermediate plants between Weigela hortensis (Siebold & Zucc.) K.Koch and W. maximowiczii (S.Moore) Rehder have been found in Miyagi and Yamagata Pref., northern Japan. Quantitative character analyses of flowers, pollen stainability and molecular analyses indicated that the intermediate plants were hybrids of those two species. This is the first record of an intersectional hybrid with W. maximowiczii (sect. Weigelastrum ) as one of the parent species. The morphological differences among hybrid individuals imply the possibility of backcrosses or formation of second or later generations of hybrids, although those may be quite rare because of a low frequency of viable pollen grains. Causes of hybridization between two distantly-related species in Weigela are discussed. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 369–380.     

Evaluation of acute and chronic toxicity of selected compounds in higher plants using cell culture

Summary The feasibility of using plant cell culture to measure toxicity was determined by investigating the toxicological effects of three chemical compounds, allyl alcohol, propargylglycine, and cadmium chloride, on cell cultures ofCatharanthus roseus G. Don (Madagascar periwinkle). Suspension cultures ofC. roseus were maintained in modified B5 medium and transferred every 5 d. Five-day-old cell cultures were exposed to various concentrations (10,3,1,0.3,0.1,0.03,0.01,0.003,0.001,0.0003,0.0001, 0.00003, and 0.0 mM) of the toxicants in both acute and chronic toxicity tests. In the acute test, cells were exposed to the toxicant for 24 h, washed three times with sterile medium, and plated in petri plates with an equal volume of 1.4% agar medium. Cells in the chronic test were plated with an equal volume of 1.4% agar medium containing various concentrations of the toxicant. Cells were incubated 28 d at 30°C in the dark. The colonies were counted and the results plotted as percent survival versus toxicant concentration. The results indicate, at the concentrations tested, thatC. roseus assay may be feasible in that it fulfills the criteria for a practical assay (e.g., rapid, simple, quantifiable, and reproducible). This work was submitted to the faculty of Miami University in partial fulfillment of the requirements for the degree of Master of Environmental Science, Institute of Environmental Sciences.     

Thermal inhibition of repair of methylmethane sulfonate-damaged DNA in chick embryo fibroblasts

Chick embryo fibroblasts were treated with the monofunctional alkylating agent methylmethane sulfonate at various concentrations for 1 h at 42°C, rinsed and then incubated post-treatment at various temperatures at which the kinetics of alkali-labile bond disappearance was followed. Growth experiments showed that these cells grew similarly at temperatures of either 37°C or 42°C. Repair as assessed by removal of alkali-labile bond was also similar for postincubation in the temperature range 37–42°C for damage due to methylmethane sulfonate treatment at concentrations less than 1.5 mM. When the postincubation temperature was raised higher than 42.5–43°C, this type of repair was stopped. The normal internal body temperature of adult chickens is about 41.6°C. Hence the present finding indicates that chick cells are much more severely restricted in DNA repair at temperatures above normal than are mammalian cells, which can function in this respect for several deg. C above 37°C.     

Effects of detergents on catalytic activity of human endometase/matrilysin 2, a putative cancer biomarker

Matrix metalloproteinases (MMPs) are a family of hydrolytic enzymes that play significant roles in development, morphogenesis, inflammation, and cancer invasion. Endometase (matrilysin 2 or MMP-26) is a putative early biomarker for human carcinomas. The effects of the ionic and nonionic detergents on catalytic activity of endometase were investigated. The hydrolytic activity of endometase was detergent concentration dependent, exhibiting a bell-shaped curve with its maximum activity near the critical micelle concentration (CMC) of nonionic detergents tested. The effect of Brij-35 on human gelatinase B (MMP-9), matrilysin (MMP-7), and membrane-type 1 MMP (MT1-MMP) was further explored. Their maximum catalysis was observed near the CMC of Brij-35 (∼ 90 μM). Their IC₅₀ values were above the CMC. The inhibition mechanism of MMP-7, MMP-9, and MT1-MMP by Brij-35 was a mixed type as determined by Dixon’s plot; however, the inhibition mechanism of endometase was noncompetitive with a K_i value of 240 μM. The catalytic activities of MMPs are influenced by detergents. Monomer of detergents may activate and stabilize MMPs to enhance catalysis, but micelle of detergents may sequester enzyme and block the substrate binding site to impede catalysis. Under physiological conditions, a lipid or membrane microenvironment may regulate enzymatic activity.     

Detection of genetic variants affecting cattle behaviour and their impact on milk production: a genome‐wide association study

Behaviour traits of cattle have been reported to affect important production traits, such as meat quality and milk performance as well as reproduction and health. Genetic predisposition is, together with environmental stimuli, undoubtedly involved in the development of behaviour phenotypes. Underlying molecular mechanisms affecting behaviour in general and behaviour and productions traits in particular still have to be studied in detail. Therefore, we performed a genome‐wide association study in an F₂ Charolais × German Holstein cross‐breed population to identify genetic variants that affect behaviour‐related traits assessed in an open‐field and novel‐object test and analysed their putative impact on milk performance. Of 37 201 tested single nucleotide polymorphism (SNPs), four showed a genome‐wide and 37 a chromosome‐wide significant association with behaviour traits assessed in both tests. Nine of the SNPs that were associated with behaviour traits likewise showed a nominal significant association with milk performance traits. On chromosomes 14 and 29, six SNPs were identified to be associated with exploratory behaviour and inactivity during the novel‐object test as well as with milk yield traits. Least squares means for behaviour and milk performance traits for these SNPs revealed that genotypes associated with higher inactivity and less exploratory behaviour promote higher milk yields. Whether these results are due to molecular mechanisms simultaneously affecting behaviour and milk performance or due to a behaviour predisposition, which causes indirect effects on milk performance by influencing individual reactivity, needs further investigation.     

Measurement of 7-dehydrocholesterol and cholesterol in hair can be used in the diagnosis of Smith-Lemli-Opitz syndrome

7-dehydrocholesterol (7-DHC) and cholesterol (CHOL) are biomarkers of Smith-Lemli-Opitz Syndrome (SLOS), a congenital autosomal recessive disorder characterized by elevated 7-DHC level in patients. Hair samples have been shown to have great diagnostic and research value, which has long been neglected in the SLOS field. In this study, we sought to investigate the feasibility of using hair for SLOS diagnosis. In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), hair samples were completely pulverized and extracted by micro-pulverized extraction in alkaline solution or in n-hexane. After microwave-assisted derivatization with N,O-Bis(trimethylsilyl)trifluoroacetamide, the analytes were measured by GC-MS. We found that the limits of determination for 7-DHC and CHOL were 10 ng/mg and 8 ng/mg, respectively. In addition, good linearity was obtained in the range of 50–4000 ng/mg and 30–6000 ng/mg for 7-DHC and CHOL, respectively, which fully meets the requirement for SLOS diagnosis and related research. Finally, by applying the proposed method to real hair samples collected from 14 healthy infants and two suspected SLOS patients, we confirmed the feasibility of hair analysis as a diagnostic tool for SLOS. In conclusion, we present an optimized and validated analytical method for the simultaneous determination of two SLOS biomarkers using human hair.     

Antiretroviral (HIV-1) activity of azulene derivatives

The antiretroviral activity of azulene derivatives was detected for the first time. A series of eighteen diversely substituted azulenes was synthesized and tested in vitro using HIV-1 based virus-like particles (VLPs) and infectious HIV-1 virus in U2OS and TZM-bl cell lines. Among the compounds tested, the 2-hydroxyazulenes demonstrated the most significant activity by inhibiting HIV-1 replication with IC₅₀ of 2–10 and 8–20 μM for the VLPs and the infectious virus, respectively. These results indicate that azulene derivatives may be potentially useful candidates for the development of antiretroviral agents.     

Stress integrated tests and cytological analyses reveal Brassica villosa subsp. drepanensis seed quality decrease upon long-term storage

Under stress integrated germination test (SIGT), seeds undergo osmo-saline stresses, which enable to detect differences in vigour of long-term stored seeds with high germination percentage (G%). The quality of Brassica villosa subsp. drepanensis seeds stored in a genebank (at ? 20°C for 16 years) was compared with seeds at harvest by standard germination tests (GT), SIGT and cytogenetic analysis. No differences were detected in G% and mean germination time under GT. Conversely, SIGT performed with NaCl ? 0.9 MPa osmotic potential did not influence G% at harvest but reduced that of stored seeds, SIGT at ? 1.4 MPa reduced G% of both. Cytogenetic analysis showed reduction of mitotic index, appearance of chromosomal aberrations and smaller nucleoli in stored seeds compared with harvest seeds germinated in water. SIGT at ? 0.9 MPa had no effect on mitotic index, but increased chromosome aberrations and nucleoli number. SIGT at ? 1.4 MPa inhibited G% of harvest and stored seeds, reduced mitoses in harvest and completely prevented it in stored seeds. The results indicate that GT does not faithfully reflect the quality of stored seeds, with misinterpretation of their vigour, whereas SIGT and cytogenetical parameters are sensitive, reliable and inexpensive methods for early prediction of genetic erosion in germplasm banks.     

Modulation of Coordinated Activity across Cortical Layers by Plasticity of Inhibitory Synapses

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Female and male Texas cichlids (Herichthys cyanoguttatum) do not fight by the same rules

Selection usually acts differently on males and females duringintrasexual competition for resources and/or mates. Nevertheless,agonistic behavior has been examined both theoretically andempirically mostly in males. Our research questions whethermales and females follow the same rules of engagement in intrasexualcontests as predicted by the sequential assessment model (SAM).The SAM predicts negative correlations between contest intensityand duration and the magnitude of asymmetry in resource holdingpower (RHP) between the contestants, such that the most escalatedcontests are those between similarly endowed individuals. Westaged male and female intrasexual contests with varying degreesof body size asymmetry under a round robin design using themonogamous Texas cichlid fish (Herichthys cyanoguttatum) asa study case. We used Mantel's matrix analysis to compare howthe behavioral content, duration, structure, and outcome ofmale and female contests were affected by the relative bodysize of the contestants. In the case of males, relative sizein each contest predicted outcome, duration, and frequency ofconventional and escalated behaviors according to prevailingtheory. Female contest structure and outcome, however, werenot predicted by the relative size of contestants. We discussour results in terms of other asymmetries that might be importantin structuring female contests, and we propose potential approachesto study female–female aggression.