Soft‐Bodied Fossils Are Not Simply Rotten Carcasses – Toward a Holistic Understanding of Exceptional Fossil Preservation

Exceptionally preserved fossils are the product of complex interplays of biological and geological processes including burial, autolysis and microbial decay, authigenic mineralization, diagenesis, metamorphism, and finally weathering and exhumation. Determining which tissues are preserved and how biases affect their preservation pathways is important for interpreting fossils in phylogenetic, ecological, and evolutionary frameworks. Although laboratory decay experiments reveal important aspects of fossilization, applying the results directly to the interpretation of exceptionally preserved fossils may overlook the impact of other key processes that remove or preserve morphological information. Investigations of fossils preserving non‐biomineralized tissues suggest that certain structures that are decay resistant (e.g., the notochord) are rarely preserved (even where carbonaceous components survive), and decay‐prone structures (e.g., nervous systems) can fossilize, albeit rarely. As we review here, decay resistance is an imperfect indicator of fossilization potential, and a suite of biological and geological processes account for the features preserved in exceptional fossils.     

Engineering of cell membrane to enhance heterologous production of hyaluronic acid in Bacillus subtilis

Hyaluronic acid (HA) is a high‐value biopolymer used in the biomedical, pharmaceutical, cosmetic, and food industries. Current methods of HA production, including extraction from animal sources and streptococcal cultivations, are associated with high costs and health risks. Accordingly, the development of bioprocesses for HA production centered on robust “Generally Recognized as Safe (GRAS)” organisms such as Bacillus subtilis is highly attractive. Here, we report the development of novel strains of B. subtilis in which the membrane cardiolipin (CL) content and distribution has been engineered to enhance the functional expression of heterologously expressed hyaluronan synthase (HAS) of Streptococcus equisimilis (SeHAS), in turn, improving the culture performance for HA production. Elevation of membrane CL levels via overexpressing components involved in the CL biosynthesis pathway, and redistribution of CL along the lateral membrane via repression of the cell division initiator protein FtsZ resulted in increases to the HA titer of up to 204% and peak molecular weight of up to 2.2 MDa. Moreover, removal of phosphatidylethanolamine and neutral glycolipids from the membrane of HA‐producing B. subtilis via inactivation of pssA and ugtP, respectively, has suggested the lipid dependence for functional expression of SeHAS. Our study demonstrates successful application of membrane engineering strategies to develop an effective platform for biomanufacturing of HA with B. subtilis strains expressing Class I streptococcal HAS.     

Sesquiterpene Lactones with COX‐2 Inhibition Activity from Artemisia lavandulaefolia

Two new sesquiterpene lactones, artelavanolides A ( 1 ) and B ( 2 ), and four known sesquiterpene lactones ( 3 – 6 ) were isolated from the leaves of Artemisia lavandulaefolia. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D‐NMR and HR‐ESI‐MS). The absolute configuration of 1 was determined by the analysis of single‐crystal X‐ray diffraction data. Artelavanolide A ( 1 ) is a rare sesquiterpene lactone possessing an unusual skeleton with the linkage of Me(14)–C(1) that is probably formed through a rearrangement of the guaiane‐type sesquiterpenoids. Artelavanolide B ( 2 ) is a new highly unsaturated guaianolide. Compounds 1 – 6 were tested for activities on the inhibition of COX‐2 enzyme in vitro. All of compounds exhibited inhibitory activity against COX‐2 with IC₅₀ values ranging from 43.29 to 287.07 μm compared with the positive control, celecoxib (IC₅₀ = 18.10 μm ). Among them, 3 showed the best COX‐2 inhibitory activity with an IC₅₀ value of 43.29 μm .     

Nature versus nurture? Consequences of short captivity in early stages

Biological changes occurring as a consequence of domestication and/or captivity are not still deeply known. In Atlantic salmon (Salmo salar), endangered (Southern Europe) populations are enhanced by supportive breeding, which involves only 6 months of captive rearing following artificial spawning of wild‐collected adults. In this work, we assess whether several fitness‐correlated life‐history traits (migratory behavior, straying rate, age at maturity, and growth) are affected by early exposure to the captive environment within a generation, before reproduction thus before genetic selection. Results showed significant differences in growth and migratory behavior (including straying), associated with this very short period of captivity in natural fish populations, changing even genetic variability (decreased in hatchery‐reared adults) and the native population structure within and between rivers of the species. These changes appeared within a single generation, suggesting very short time of captivity is enough for initiating changes normally attributed to domestication. These results may have potential implications for the long‐term population stability/viability of species subjected to restoration and enhancement processes and could be also considered for the management of zoo populations.     

Simplifying understory complexity in oil palm plantations is associated with a reduction in the density of a cleptoparasitic spider,Argyrodes miniaceus (Araneae: Theridiidae), in host (Araneae: Nephilinae) webs

Expansion of oil palm agriculture is currently one of the main drivers of habitat modification in Southeast Asia. Habitat modification can have significant effects on biodiversity, ecosystem function, and interactions between species by altering species abundances or the available resources in an ecosystem. Increasing complexity within modified habitats has the potential to maintain biodiversity and preserve species interactions. We investigated trophic interactions between Argyrodes miniaceus, a cleptoparasitic spider, and its Nephila spp. spider hosts in mature oil palm plantations in Sumatra, Indonesia. A. miniaceus co‐occupy the webs of Nephila spp. females and survive by stealing prey items caught in the web. We examined the effects of experimentally manipulated understory vegetation complexity on the density and abundance of A. miniaceus in Nephila spp. webs. Experimental understory treatments included enhanced complexity, standard complexity, and reduced complexity understory vegetation, which had been established as part of the ongoing Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Project. A. miniaceus density ranged from 14.4 to 31.4 spiders per square meter of web, with significantly lower densities found in reduced vegetation complexity treatments compared with both enhanced and standard treatment plots. A. miniaceus abundance per plot was also significantly lower in reduced complexity than in standard and enhanced complexity plots. Synthesis and applications: Maintenance of understory vegetation complexity contributes to the preservation of spider host–cleptoparasite relationships in oil palm plantations. Understory structural complexity in these simplified agroecosystems therefore helps to support abundant spider populations, a functionally important taxon in agricultural landscapes. In addition, management for more structurally complex agricultural habitats can support more complex trophic interactions in tropical agroecosystems.     

Long‐term regeneration of a tropical plant community after sand mining

Sandy coastal plant communities in tropical regions have been historically under strong anthropic pressure. In Brazil, these systems shelter communities with highly plastic plant species. However, the potential of these systems to regenerate without human assistance after disturbances has hardly been examined. We determined the natural regeneration of a coastal sandy plain vegetation (restinga) in Brazil, 16 years after the end of sand removal. We inventoried 38 plots: 20 within a sand‐mined site and 18 in an adjacent undisturbed site. We expected lower diversity values in the sand‐mined site compared to the undisturbed site, but similar species composition between the two sites due to the spatial proximity of the two sites and the high plasticity of restinga species. Species were ranked using abundance and importance value index in both sites, and comparisons were performed using Rényi entropy profiles, rarefaction curves, principal component analysis, and redundancy analysis. Species composition and dominant species differed markedly between the two sites. Bromeliads and Clusia hilariana, well‐known nurse plants, dominated the undisturbed site but were almost absent in the regenerating site. Species richness did not differ between both sites, but diversity was higher in the undisturbed site. Within‐site composition differences in the mined area were associated with field characteristics. Interestingly, species classified as subordinate or rare in the undisturbed site became dominants in the regenerating site. These newer dominants in the sand‐mined site are not those known as nurse plants in other restingas, thus yielding strong implications for restoration.     

Using antagonistic soil bacteria and their cell‐free filtrates to control the black rot pathogen Xanthomonas campestris pv. campestris

Xanthomonas campestris pv. campestris (Xcc) is a phytopathogenic bacteria, and it is the causative agent of black rot in crucifers. Recent studies have shown that Bacillus species have strong biological control on Xanthomonas. One of the mechanisms of this control is secondary metabolites production. A collection of 257 bacteria isolated from a suppressive soil was evaluated for in vitro antagonistic activity against X. campestris, and 92 isolates (44.6%) were able to inhibit its growth. Among the 92 isolates evaluated in the double‐layer technique, 51 (55.43%) inhibited Xcc growth on the inhibition tests with cell‐free filtrates (CFF) in liquid medium. Thirteen of these isolates presented 50% or more growth inhibition, and five isolates presented 100% growth inhibition of Xcc. The CFF of the isolate TCDT‐08, which belongs to the Paenibacillus genus, was used for in vivo tests with kale crops. The artificial inoculation of kale with Xcc‐629IBSBF pretreated with CFF from the isolate TCDT‐08 demonstrated that the bacterium loses the ability of colonizing kale and of causing black rot. A Paenibacillus sp. isolate has strong inhibitory activity against X. campestris pv. campestris, and further studies can result in the use of this isolate to protect kale from Xcc infection.     

Bothriospermum longistylum sp. nov. (Boraginaceae) from north China

Based on field investigations as well as morphological and molecular systematic studies we found a new species of Bothriospermum which can be easily distinguished from all other known congeneric species by its unlobed faucal appendages and very long styles. We conducted molecular phylogenetic analyses based on a combined dataset from nrITS, plastid rps16, trnL‐trnF and trnG‐trnS regions. The results indicated that the new species indeed belongs in Bothriospermum and that it is well separated from other congeneric clusters, but that the genus Bothriospermum is paraphyletic with Nihon and Thyrocarpus clusetered within it. As a result, Bothriospermum longistylum sp. nov. is described and illustrated here. A revised key to species of Bothriospermum and a distributional map are also presented.