Low‐temperature physiology of climatically distinct south African populations of the biological control agent Neochetina eichhorniae

1. Neochetina eichhorniae is the most widely established biocontrol agent on water hyacinth populations around South Africa. However, some N. eichhorniae populations have failed to adequately control their host population, specifically those exposed to cold conditions.
2. The aim of this study was to determine whether two climatically distinct populations of N. eichhorniae in South Africa differ in their low‐temperature physiology, which tests whether local‐climate adaptation has occurred.
3. We estimated weevil CT_min, LLT₅₀, SCP, and SCP mortality using standard approaches. Contrary to expectation based on climatic thermal profiles at the two sites, weevils from the warm locality ((mean ± SE) CT_min = 5.0 °C ± 0.2, LLT₅₀ = ?11.3 °C ± 0.03, SCP = ?15.8 °C ± 0.6) were able to maintain activity and tolerate colder temperatures than the weevils from the colder site (CT_min = 6.0 °C ± 0.5, LLT₅₀ = ?10.1 °C ± 0.1, SCP = ?12.9 °C ± 0.8).
4. These contradictory outcomes are likely explained by the poor nutrient quality of the plants at the cold site, driving low‐temperature performance variation that overrode any macroclimate variation among sites. The cold site weevils may also have adapted to survive wide‐temperature variability, rather than perform well under very cold conditions. In contrast, the mass‐reared population of insects from the warm site has likely adapted to the consistent conditions that they experience over many years in confinement.

     

Interactions of phytochrome and exogenous gibberellic acid on germination of Lamium amplexicaule L. seeds

Summary In henbit (Lamium amplexicaule L.) seeds, micromolar levels of gibberellic acid (GA₃) introduced at the onset of imbibition markedly stimulated germination. Sensitivity to GA₃ stimulation is rapidly lost if the seeds are pretreated in darkness at 15° for 1 day or more on a water substrate. Loss in responsiveness to GA₃ is hastened by pretreatment in far-red or by dark pretreatment at higher (25°) temperatures and is reduced by pretreatments at 5°. A portion of the lost responsiveness to GA₃ at 15° or higher is attributable to onset of a secondary dormancy, but the results of far-red treatment at 5°, where secondary dormancy is not a factor, clearly indicate that some phytochrome in the far-red absorbing form increased the effectiveness of gibberellic acid action.Abbreviations GA gibberellin - GA₃ gibberellic acid - R red light - FR far-red - P_r red-absorbing form of phytochrome - P_fr far-red-absorbing form of phytochrome Mention of a trade name or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable     

Engineering a synthesis-friendly serum responsive promoter for antibiotic selection of genomic integration in cell-based therapy

Biotechnology Letters - For clinical cell-based therapies (e.g. CAR-T cells), the genomic integration of therapeutic genes into cells are selected using inefficient resistance genes of host origin...     

The Role of Thermal Regime in Tundra Plant Community Restoration

Mineral extraction activities in the Arctic regions of the world produce long-lasting ecological disturbances. Assisted recovery from such disturbances may require restoration of the tundra thermal regime. We transplanted plugs of entire root zone and live tundra plants to a disturbed site in Alaska oil fields. The dominant species were Carex aquatilis, Eriophorum angustifolium, Dupontia fisheri, Poa glauca, Festuca rubra, Salix ovalifolia, S. reticulata, and Sphagnum spp. We studied plant responses in the plugs to thermal regime manipulations by means of greenhouse and of single- or double-plug treatments. All plugs continued to produce new plants with time and expanded in area and canopy volume. Plants responded differently to treatments and generally reversed those responses when we reversed the greenhouse treatment the third year after transplant. Our small-scale experiment showed that the native thermal regime of a plant community is vital in revegetating a disturbed tundra. But large-scale restoration using transplants requires resources of modern extraction technology, engineering, and planning to salvage the extensive live tundra mats now routinely destroyed under gravel fills of roads, structures, and mine-site stockpiles.