Smoke Solutions and Temperature Influence the Germination and Seedling Growth of South African Mesic Grassland Species

Fire, natural or of anthropologic origin, is a recurrent phenomenon in South African mesic grassland. The species composition of these grasslands is sensitive to fire, particularly fire frequency. However, the mechanisms involved in influencing species composition are not fully understood. Currently there is a general suggestion that plant-derived smoke and smoke-isolated biologically active butenolide compound provide an important germination cue for a range of Poaceae species. Studies also show that these smoke solutions play a role in vegetative growth of many plants. We examined if this fire-response syndrome is related to the effect of plant-derived smoke-water (1:500 v/v) and smoke-derived butenolide compound (10^-8 M) on seed germination and seedling growth of six major constituent species of the grassland. In addition, the interaction of the smoke solutions with temperature was examined by incubating seeds at a range of temperatures. Treating seeds with smoke-water and butenolide, the germination rate and final germination percentage were greater in three of the six species. Themeda triandra Forssk. and Tristachya leucothrix Trin. ex Nees showed the greatest response, with final germination increased from 43% to 67% and 35% to 63%, respectively. With increasing temperature (> 30°C), Aristida junciformis Trin. & Rupr., Hyparrhenia hirta (L.) Staph, and Panicum maximum Jacq. responded positively to the test solutions. In nearly all the species tested, smoke-water–treated seeds produced significantly longer shoots or roots. However, the degree of response varied from species to species and across different temperatures. Findings from this study suggest that plant-derived smoke and its interaction with temperature may significantly influence the germination and seedling growth of the South African mesic grassland species, which can further alter the grassland composition.     

Honeycomb and simple mass selection for herb yield and inflorescence to leaf + stem ratio in palmarosa grass

Summary Honeycomb and simple mass selection for herb yield and inflorescence to leaf + stem ratio were studied in a population of palmarosa (Cymbopogon martini Stapf. var. motia) grown at a plant spacing of 90 cm. The inflorescence to leaf + stem ratio was studied for indirect selection for oil content. The effects of selection were evaluated at high (30×30 cm) and low (45×45 cm) plant densities. Honeycomb selection was effective in improving herb yield at both plant densities while simple mass selection was effective only at low plant density. Both selection methods were equally effective in improving inflorescence to leaf + stem ratio but only when the populations were grown at low plant density. Increases in oil content were obtained even when selection for an increased inflorescence to leaf + stem ratio was ineffective. Improvements in each of the three studied traits did not affect any other studied trait.     

The mechanism and inheritance of intraflower self-pollination in self-pollinating variant strains of periwinkle

The mechanism and inheritance of intraflower self‐pollination in self‐pollinating variant strains of periwinkle was studied using three self‐pollinating and two non‐self‐pollinating but fully self‐fertile strains. Intraflower self‐pollination in self‐pollinating strains occurred due to the continued growth of the gynoecium beyond the base of the anthers, even after anthesis, resulting in intraflower self‐pollination. In non‐self‐pollinating strains, the stigma remained below the base of the anthers and did not come into contact with the pollen up to flower drop. Intraflower self‐pollination was found to be governed by duplicate recessive genes. The utility of the intraflower self‐pollination trait in the breeding of periwinkle cultivars is discussed.     

Molecular Basis of Gene-for-Gene Specificity in Bacterial Speck Disease of Tomato

Transient expression of the Pseudomonas syringae avirulence gene avrPto in plant cells resulted in a Pto-dependent necrosis. The AvrPto avirulence protein was observed to interact directly with the Pto resistance protein in the yeast two-hybrid system. Mutations in the Pto and avrPto genes which reduce in vivo activity had parallel effects on association in the two-hybrid assay. These data suggest that during infection the pathogen delivers AvrPto into the plant host cell and that resistance is specified by direct interaction of Pto with AvrPto.     

Smoke‐water and karrikinolide (KAR1) foliar applications promote seedling growth and photosynthetic pigments of the biofuel seed crop Jatropha curcas L.

This greenhouse study tested the effect of smoke‐water and the smoke‐isolated biologically active compound karrikinolide (KAR₁) on growth and photosynthetic pigments of Jatropha curcas L. seedlings. Fifteen‐day‐old seedlings were sprayed once weekly for 5 weeks with three dilutions of smoke‐water (1 : 250, 1 : 500, and 1 : 1000 v/v) or KAR₁ (10^–7, 10^–8, and 10^–9 M). Growth parameters and photosynthetic pigment concentrations of 75‐d‐old seedlings were measured. Foliar application of both smoke‐water and KAR₁ on J. curcas seedlings showed significant increases in stem width, shoot length, chlorophyll a, chlorophyll b, total chlorophyll, and total carotenoid concentrations compared to the untreated control. KAR₁ significantly improved leaf area, shoot and root dry mass, seedling‐vigor index, and photosynthetic pigments as compared to control treatments. These results suggest the possible use of smoke‐water and KAR₁ to achieve a vigorous and well established crop of J. curcas.     

Nano-Bio-Genesis: tracing the rise of nanotechnology and nanobiotechnology as 'big science'

Nanotechnology research has lately been of intense interest because of its perceived potential for many diverse fields of science. Nanotechnology's tools have found application in diverse fields, from biology to device physics. By the 1990s, there was a concerted effort in the United States to develop a national initiative to promote such research. The success of this effort led to a significant influx of resources and interest in nanotechnology and nanobiotechnology and to the establishment of centralized research programs and facilities. Further government initiatives (at federal, state, and local levels) have firmly cemented these disciplines as 'big science,' with efforts increasingly concentrated at select laboratories and centers. In many respects, these trends mirror certain changes in academic science over the past twenty years, with a greater emphasis on applied science and research that can be more directly utilized for commercial applications.We also compare the National Nanotechnology Initiative and its successors to the Human Genome Project, another large-scale, government funded initiative. These precedents made acceptance of shifts in nanotechnology easier for researchers to accept, as they followed trends already established within most fields of science. Finally, these trends are examined in the design of technologies for detection and treatment of cancer, through the Alliance for Nanotechnology in Cancer initiative of the National Cancer Institute. Federal funding of these nanotechnology initiatives has allowed for expansion into diverse fields and the impetus for expanding the scope of research of several fields, especially biomedicine, though the ultimate utility and impact of all these efforts remains to be seen.     

Cilia and cilia-related disorders

Abstract

Extract

Among the puzzling aspects of the recently described autosomal recessive polycystic kidney disease (ARPKD) of sheep (Johnstone et al 2005 Johnstone, AC, Davidson, BI, Roe, AR, Eccles, MR and Jolly, RD. 2005. Congenital polycystic kidney disease in lambs. New Zealand Veterinary Journal, 53: 307–314. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) is the multiplicity of organ systems affected and the phenotypic variations that occur between the various animal species. It has been shown in studies of other inherited polycystic kidney disease syndromes that the normal gene products of a mutant are likely to be involved in ciliary structure and function. The studies that have led to this recognition can be expected to eventually provide the basis for a better understanding of the functioning of this organelle, and the pathogenesis of lesions in the related diseases.

It is well known that cilia are important in the perception of light, olfactory stimuli and sound and that motile cilia provide cell motility (e.g. sperm) and transport of mucus and other fluids. Recent research has indicated that the involvement of the primary cili-um/basal body complex is of central importance in the detection and cellular response to extracellular movement of fluid, critical phases of embryonic development, cell cycle regulation and maintenance of cell polarity.

Confocal microscopic studies of renal cyst epithelium in ovine ARPKD have shown that only 30% of cells have a cilium and that these are often truncated (McGlashan et al 2005 McGlashan, SR, Poole, CA, Stayner, C, Johnstone, AC, Eccles, MR and Jensen, CG. 2005. “Primary cilia in fibrosis associated with two models of polycystic kidney disease”. In Proceedings of the 45th Annual Conference of the American Society for Cell Biology December 10–14 [Google Scholar]). The observation, although preliminary, strongly supports the argument that the mutant gene in this disease of sheep normally encodes for a protein essential for primary ciliary function.     

Assessment of 2 Salmonella enterica serovar Typhimurium-based vaccines against necrotic enteritis in reducing colonization of chickens by Salmonella serovars of different serogroups

This study assessed the protective efficacy of oral vaccination with 2 experimental attenuated Salmonella Typhimurium-vectored vaccines for necrotic enteritis in protecting chickens against intestinal colonization by common serovars of Salmonella belonging to the 4 major serogroups affecting chickens. Birds were vaccinated orally with 1 × 10⁸ colony-forming units (CFU) of 1 of the vaccine strains χ9241 and χ9352, which express a plasmid-encoded partial recombinant hypothetical protein gene (tHP) of Clostridium perfringens, at days 1 and 7 of age, and then were challenged at 14 d of age with 10⁶ CFU of Salmonella serovars Anatum, Enteritidis, Heidelberg, Kentucky, or Typhimurium (representative serovars of serogroups B, C, D, and E). Birds were necropsied at 4 wk of age, and samples were collected to determine reduction in tissue and intestinal colonization. The chickens vaccinated with χ9241-tHP showed reduced colonization by Salmonella Enteritidis (serogroup D) and by Salmonella Heidelberg and Salmonella Typhimurium (serogroup B) compared with the control birds. No reduction in colonization was observed in the chickens vaccinated with χ9352-tHP. There was an association between the efficacy of these vaccine strains in protecting against necrotic enteritis, assessed on an earlier occasion, and their efficacy in protecting against Salmonella colonization. Thus, the choice of an attenuated Salmonella Typhimurium vaccine vector for delivery of heterologous antigens to chickens should be based partly on the vaccine’s value in protecting against colonization by serovars within serogroups B and D. Such vectors would have the additional benefit of reducing colonization of important Salmonella serovars.     

Effects of Gonadotropins on In Vitro Maturation and of Electrical Stimulation on Parthenogenesis of Canine Oocytes

The objective of this study was to determine the effects of gonadotropins on in vitro maturation (IVM) and electrical stimulation on the parthenogenesis of canine oocytes. In experiment I, cumulus oocyte complexes were collected from ovaries at a random phase of the oestrus cycle and cultured on maturation medium treated with hCG or eCG for 48 or 72 h. There were no significant differences in the effects on the metaphase II (MII) rate between the hCG and eCG treatment groups over 48 h (5.4% vs 5.5%). The MII rate in the co-treatment group of hCG and eCG for 48 h was higher than in each hormone treated group (15.5%, p < 0.05). In experiment 2, the parthenogenetic effect on oocyte development, at various electrical field strengths (1.0, 1.5, 2.0 kV/cm DC) for 60 or 80 μs with a single DC pulse after IVM on the co-treatment of hCG and eCG, was examined. The rate of pronuclear formation (37.1%) in electrical activation at 1.5 kV/60 μs without cytochalasin B (CB) was higher than that of oocytes activated in the other groups (p < 0.05). However, we did not observe the cleavage stages. Also, CB did not influence parthenogenesis of canine oocytes. The results showed that the pronucleus formation rate, indicative of the parthenogenesis start point, could be increased by electrical stimulation. Therefore, these results can provide important data for the parthenogenesis of canine oocytes and suggest the probability of parthenogenesis in canines.