Every rose has its thorn: Infants' responses to pointed shapes in naturalistic contexts

Plants produce dangerous chemical and physical defenses that have shaped the physiology and behavior of the herbivorous predators that feed on them. Here we explore the impact that these plant defenses may have had on humans by testing infants' responses to plants with and without sharp-looking thorns. To do this, we presented 8- to 18-month-olds with plants and control stimuli and measured their initial reaching behavior and subsequent object exploration behavior. Half of the stimuli had sharp-looking thorns or pointed parts while the other half did not. We found that infants exhibited both an initial reluctance to touch and minimized subsequent physical contact with plants compared to other object types. Further, infants treated all plants as potentially dangerous, whether or not they possessed sharp-looking thorns. These results reveal novel dimensions of a behavioral avoidance strategy in infancy that would mitigate potential harm from plants.     

No Dog Left Behind: A Hedonic Pricing Model for Animal Shelters

Companion animal overpopulation is a growing problem in the United States. In addition to strays, an average of 324,500 nonhuman animals are relinquished to shelters yearly by their caregivers due to family disruption (divorce, death), foreclosure, economic problems, or minor behavioral issues. As a result, estimates of animals in shelters range from 3 million to 8 million, and due to overcrowding, euthanasia is common. This analysis seeks to determine the appropriate pricing mechanisms to clear animal shelters of dogs in the manner most desirable—that is, through adoption. Based on a survey of Michigan residents, it is clear there are a number of correlations between the traits of dogs and the individuals who care for them. Hedonic pricing models indicate that animal shelters need to proactively vary their pricing systems to discount particular traits, specifically for mixed-breed, older, and black dogs. Premiums can be charged for puppies, purebred dogs, and those who have received specific services such as microchipping.     

Production of plant secondary metabolites without plants: a perspective

Efforts to commercially exploit native plant secondary metabolite production patterns in cell culture systems have been largely thwarted by the repression of secondary metabolism under growth-oriented culture conditions. Where expression can be obtained by selection or elicitation, the difficulties of large scale cultivation/processing still make the cost effectiveness of cell culture systems dubious except where a very high value market niche can be identified.

The long range prospect for efficiently utilizing the catalytic genius of higher plants resides in the transfer of appropriate genetic information to microbial systems for whom the fermentation expertise and industrial facilities already exist.     

Certainly can't live without this: SIRT6

Cellular metabolic rates might regulate aging by impinging on genomic stability through the DNA repair pathways. A new study published in Cell (Mostoslavsky et al., 2006) reports that deficiency in one of the mammalian Sir2 homologs, SIRT6, results in genome instability through the DNA base excision repair pathway and leads to aging-associated degenerative phenotypes.     

Weapon (thorn) automimicry and mimicry of aposematic colorful thorns in plants

In order to further characterize the function of coloration in plants as defense against herbivory, two types of thorn mimicry are described: (1) A unique type of weapon (thorn) automimicry (within the same individual) that was previously known only in animals, and (2) mimicry of aposematic colorful thorns, by colorful elongated and pointed plant organs (buds, leaves and fruit) that, despite their appearance, are not sharp. Some thorny plants including dozens of species of Agave, one species of Aloe and a palm species have thorn-like imprints or colorations on their leaves, constituting thorn automimicry by giving the impression of more extensive thorns. The mimicry of aposematic colorful thorns is a typical case of Batesian mimicry, but the thorn automimicry is a special intra-organismic Batesian mimicry. I propose that both types of mimicry serve as anti-herbivore mechanisms.     

Somatic embryogenesis and regeneration of flowering plants in rose

Summary Somatic embryos of the cut rose cultivars Domingo and Vickey Brown were obtained from callus derived from leaf explants on half strength Murashige and Skoog medium with low concentrations of kinetin and 1-naphthyl acetic acid or 2-naphthyloxyacetic acid. Somatic embryos were first observed after 6 to 12 weeks of culture on callus formed at the basis or midrib of the leaf. Embryos could be grown to phenotypically true to type greenhouse plants.Abbreviations IAA 3-indole-acetic acid - IBA indole-3-butyric acid - NAA 1-naphthylacetic acid - NOA 2-naphthyloxyacetic acid - BAP 6-benzylaminopurine - KIN 6-furfurylaminopurine - MS Murashige and Skoog     

Effects of sodium on mineral nutrition in rose plants

The effects of sodium (Na⁺) ion concentration on shoot elongation, uptake of ammonium (NH₄⁺) and nitrate (NO₃^?) and the activities of nitrate reductase (NR) and glutamine synthetase (GS) were studied in rose plants (Rosa hybrida cv. “Lambada”). The results showed that shoot elongation was negatively correlated with sodium concentration, although no external symptoms of toxicity were observed. Nitrate uptake decreased at high sodium levels, specifically at 30 meq litre4 of sodium. As flower development was normal under high saline conditions, this could suggest that nitrogen was being mobilised from shoot and leaf reserves. Ammonium uptake was not affected by any of the salt treatments applied probably because it diffuses through the cell membrane at low concentrations. Nitrate reductase activity was reduced by 50% at 30 meq litre 1 compared with control treatment, probably due to a decrease in the free nitrate related to nitrate uptake pattern. None of the salt treatments used affected total leaf GS activity (both chloroplastic and cytosolic isoforms) or leaf NPK mineral contents. Nitrate reductase activity in leaves increased at 10 meq litre^?1 of sodium and GS activity in roots (cytosolic isoform only) followed the same pattern as NR. It is suggested that the activation of both enzymes at low salt level could be attributed to the beneficial effect of increased sulphur in the nutrient solutions.     

Plant programmed cell death: can't live with it; can't live without it

The decision of whether a cell should live or die is fundamental for the wellbeing of all organisms. Despite intense investigation into cell growth and proliferation, only recently has the essential and equally important idea that cells control/programme their own demise for proper maintenance of cellular homeostasis gained recognition. Furthermore, even though research into programmed cell death (PCD) has been an extremely active area of research there are significant gaps in our understanding of the process in plants. In this review, we discuss PCD during plant development and pathogenesis, and compare/contrast this with mammalian apoptosis.     

Growth interactions between calli and explants of rose plants in vitro

Growth of explants or calli of two rose cultivars ‘Sonia’ and ‘Golden Times’, was extensively promoted when they were grown on agar together with calli of rose rootstocks Rosa indica or Rosa canina, while growth of callus of a miniature rose cultivar was either not affected or inhibited. The growth of R. indica callus was inhibited when accompanied by explants of ‘Sonia’ or ‘Golden Times’. Promotion or inhibition of explants or callus growth was also observed when the agar medium was supplemented with conditioned liquid medium from cell suspension cultures of cv. Sonia or R. indica. Autoclaved conditioned medium from R. indica lost its promoting effect, while that from Sonia lost its inhibiting effect after autoclaving. The possible interaction between the rootstock and scion tissues is discussed.     

Nitrogen exchanges: testing the hypothesis of a country without agricultural production

Today, finding data on agricultural nitrogen balances is quite easy. Calculations of such balances are carried out by most of the European countries as an indicator of environmental pollution attributable to the agricultural sector. In France, average values of agricultural nitrogen balances show an excess of 1.5 to 2 million tons of nitrogen. This excess is enormous. What would the balance of a country be if agricultural activity were stopped? In the following article, a country (France is used as an example) without agriculture is studied in order to assess its nitrogen balance. Using a previously published model describing nitrogen input and output of a given country, nitrogen flows are identified. Inputs include deposition, fixation, and products not intended for agricultural use. Outputs are reduced to zero if agriculture disappears (in France, agriculture is the only sector exporting products containing nitrogen). All flows are calculated considering the hypothesis of disappearance of agriculture. Nitrogen requirements to feed people and pets in France are estimated based on medical and veterinary data (recommended daily amounts for proteins and/or usual average consumption). Indeed, most of the food that nourishes the French population is produced nationally. If agriculture stops, it will be necessary to import food from foreign countries. Results show an unexpectedly high excess (for a country without agriculture having a structure similar to France: number of human beings and pets) of 1.5 million tons of nitrogen. An attempt to calculate an agricultural balance with the same data gives a result close to 3 million tons. Differences in French agricultural balances found in the literature can mainly be explained by values taken into account for deposition and fixation (values used here are at least 300,000 tons higher than values used by the Organisation for Economic Co-operation and Development). In conclusion, nitrogen excess in agriculture is partly due to social demand; agriculture does not only produce food but also includes many other functions (landscape management, employment, and preservation of culture, for example). As a consequence, efforts that do not involve suppressing agriculture should be made to figure out alternative ways of production.     

Effects on chemical surface properties of tuff by growing rose plants

The desorption and solubilization characteristics of scoria tuff, a volcanic material used as growth substrate under protected environments and in the open fields were determined following two years of rose growing, and compared with uncropped fertigated tuff and with original, unfertigated tuff. Rose growing in the tuff increased the tuff's water-soluble P, Ca and Mg concentrations and decreased the Al and Si concentrations, compared with plantless and intact tuff sources. It is suggested that these changes stemmed from accumulation of soluble organic compounds exuded by roots or released from decomposing dead roots in the cultivated tuff.     

Unravelling developmental dynamics: transient intervention and live imaging in plants

Plant development is dynamic in nature. This is exemplified in developmental patterning, in which roots and shoots rapidly elongate while simultaneously giving rise to precisely positioned new organs over a time course of minutes to hours. In this Review, we emphasize the insights gained from simultaneous use of live imaging and transient perturbation technologies to capture the dynamic properties of plant processes.     

Smart plants: Memory and communication without brains

The immobility of plants is consistent with their principal function: collecting light to provide photosynthetic substrate for the biological system. Their immobility does impose limitations on some basic requirements, such as the need for pollination, for seed dispersal, and for protection against herbivores. Meeting these 3 needs will logically necessitate some ability for plant communication – at least a capability for beneficial adaptive behavior. Three types of plant behavior provide evidence of memory and communication abilities: a capability for memory, a capability for measuring time, and extensive evidence of chemical signaling systems. These may provide benefits for genetic outcrossing, seed dispersal and protection – beneficial adaptive behaviors. The chemical signaling system constitutes a wireless communication network that draws mobile animals into assisting plant functions that require mobility. Plants share their chemical signaling systems most frequently with insects and birds. These beneficial adaptable behaviors may be interpreted as some type of consciousness.     

Can’t live without them, can live with them: roles of caspases during vital cellular processes

Since the pioneering discovery that the genetic cell death program in C. elegans is executed by the cysteine-aspartate protease (caspase) CED3, caspase activation has become nearly synonymous with apoptosis. A critical mass of data accumulated in the past few years, have clearly established that apoptotic caspases can also participate in a variety of non-apoptotic processes. The roles of caspases during these processes and the regulatory mechanisms that prevent unrestrained caspase activity remain to be fully investigated, and may vary in different cellular contexts. Significantly, some of these processes, such as terminal differentiation of vertebrate lens fiber cells and red blood cells, as well as spermatid terminal differentiation and dendritic pruning of sensory neurons in Drosophila, all involve proteolytic degradation of major cellular compartments, and are conceptually, molecularly, biochemically, and morphologically reminiscent of apoptosis. Moreover, some of these model systems bear added values for the study of caspase activation/apoptosis. For example, the Drosophila sperm differentiation is the only system known in invertebrate which absolutely requires the mitochondrial pathway (i.e. Cyt c). The existence of testis-specific genes for many of the components in the electron transport chain, including Cyt c, facilitates the use of the Drosophila sperm system to investigate possible roles of these otherwise essential proteins in caspase activation. Caspases are also involved in a wide range of other vital processes of non-degenerative nature, indicating that these proteases play much more diverse roles than previously assumed. In this essay, we review genetic, cytological, and molecular studies conducted in Drosophila, vertebrate, and cultured cells, which underlie the foundations of this newly emerging field.