Environmental and chemical control of growth and flowering of Chamelaucium uncinatum Schauer

The main factor affecting floral initiation of Geraldton Wax-Flower (Chamelaucium uncinatum) is the photoperiod, while temperature is the major factor affecting flower development. Four weeks of short days (SD) are generally required for obtaining full flowering. The number of flowers produced per plant increases with increasing the number of SD. Under mild temperatures of $\text{20}\text{14°}\text{C}$ (day/night), plants initiated flowers even in long days (LD). However, fewer flowers were produced and on higher nodes as compared to SD plants. Chlormequat promoted flowering under prevailing summer conditions of high temperatures and LD. Under prevailing autumn conditions favourable for flower initiation, LD treatment or weekly sprays with gibberellic acid (GA) reduced the number of flowers per plant. Combined treatment of LD and GA reduced both the flowering percentage and the number of flowers per plant. Discontinuing the LD or the GA treatments caused a resumption of full flower initiation.     

Pattern-oriented modeling of agent-based complex systems: lessons from ecology

Agent-based complex systems are dynamic networks of many interacting agents; examples include ecosystems, financial markets, and cities. The search for general principles underlying the internal organization of such systems often uses bottom-up simulation models such as cellular automata and agent-based models. No general framework for designing, testing, and analyzing bottom-up models has yet been established, but recent advances in ecological modeling have come together in a general strategy we call pattern-oriented modeling. This strategy provides a unifying framework for decoding the internal organization of agent-based complex systems and may lead toward unifying algorithmic theories of the relation between adaptive behavior and system complexity.     

Intercalation of sea urchin proteins in calcite: study of a crystalline composite material

Sea urchin skeletal elements are composed of single crystals of calcite. Unlike their synthetic counterparts, these crystals do not have well-developed cleavage and are consequently much more resistant to fracture. This phenomenon is due in part to the presence of acidic glycoproteins occluded within the crystals. By means of x-ray diffraction with synchrotron radiation, it is shown that the presence of the protein in synthetic calcite only slightly decreases the coherence length but significantly increases the angular spread of perfect domains of the crystals. In biogenic calcite, the coherence length is 1/3 to 1/4 as much as that in synthetic calcite and the angular spread is 20 to 50 times as wide. It is proposed that the presence of macromolecules concentrated at mosaic boundaries that are oblique to deavage planes is responsible for the change in fracture properties. These results may be important in the material sciences, because of the unusual nature of this material, namely, a composite based on the controlled intercalation of macromolecules inside single-crystal lattices.     

Innate lymphoid cells promote anatomical containment of lymphoid-resident commensal bacteria

The mammalian intestinal tract is colonized by trillions of beneficial commensal bacteria that are anatomically restricted to specific niches. However, the mechanisms that regulate anatomical containment remain unclear. Here, we show that interleukin-22 (IL-22)-producing innate lymphoid cells (ILCs) are present in intestinal tissues of healthy mammals. Depletion of ILCs resulted in peripheral dissemination of commensal bacteria and systemic inflammation, which was prevented by administration of IL-22. Disseminating bacteria were identified as Alcaligenes species originating from host lymphoid tissues. Alcaligenes was sufficient to promote systemic inflammation after ILC depletion in mice, and Alcaligenes-specific systemic immune responses were associated with Crohn's disease and progressive hepatitis C virus infection in patients. Collectively, these data indicate that ILCs regulate selective containment of lymphoid-resident bacteria to prevent systemic inflammation associated with chronic diseases.