Understanding 3D structural complexity of individual Scots pine trees with different management history

Tree functional traits together with processes such as forest regeneration, growth, and mortality affect forest and tree structure. Forest management inherently impacts these processes. Moreover, forest structure, biodiversity, resilience, and carbon uptake can be sustained and enhanced with forest management activities. To assess structural complexity of individual trees, comprehensive and quantitative measures are needed, and they are often lacking for current forest management practices. Here, we utilized 3D information from individual Scots pine (Pinus sylvestris L.) trees obtained with terrestrial laser scanning to, first, assess effects of forest management on structural complexity of individual trees and, second, understand relationship between several tree attributes and structural complexity. We studied structural complexity of individual trees represented by a single scale‐independent metric called “box dimension.” This study aimed at identifying drivers affecting structural complexity of individual Scots pine trees in boreal forest conditions. The results showed that thinning increased structural complexity of individual Scots pine trees. Furthermore, we found a relationship between structural complexity and stem and crown size and shape as well as tree growth. Thus, it can be concluded that forest management affected structural complexity of individual Scots pine trees in managed boreal forests, and stem, crown, and growth attributes were identified as drivers of it.     

Structure and phospholipid transfer activity of human PLTP: analysis by molecular modeling and site-directed mutagenesis.

The plasma phospholipid transfer protein (PLTP) is an important regulator of high density lipoprotein (HDL) metabolism. We have here, based on sequence alignments of the plasma LPS-binding/lipid transfer protein family and the X-ray structure of the bactericidal/permeability increasing protein (BPI), modeled the structure of PLTP. The model predicts a two-domain architecture with conserved lipid-binding pockets consisting of apolar residues in each domain. By site-directed mutagenesis of selected amino acid residues and transient expression of the protein variants in HeLa cells, the pockets are shown to be essential for PLTP-mediated phospholipid transfer. A solid phase ligand binding assay was used to determine the HDL-binding ability of the mutants. The results suggest that the observed decreases in phospholipid transfer activity of the N-terminal pocket mutants cannot be attributed to altered HDL-binding, but the C-terminal lipid-binding pocket may be involved in the association of PLTP with HDL. Further, the essential structural role of a disulfide bridge between cysteine residues 146 and 185 is demonstrated. The structural model and the mutants characterized here provide powerful tools for the detailed analysis of the mechanisms of PLTP function.     

Evaluation of trichothecene and nontrichothecene mycotoxins produced byFusarium in soybeans

Each of 12 cultures ofFusarium, comprising four species, isolated from moldy soybeans suspected of being involved in illness of wild geese, were grown separately in autoclaved moist rice, in autoclaved moist soybeans, and in surface sterilized-disinfected soybeans, assayed for various mycotoxins, and fed to rats. Four additional cultures that produced known toxins on rice were also grown on soybeans as controls. All isolates, except one ofF moniliforme, grown in rice resulted in weight loss of rats, and that one resulted in weight gain; 12 of the isolates caused death. One isolate ofF poae grown in soybeans caused death when consumed by rats, but none of the other 15 resulted in weight loss or overt injury. Much larger amounts of zearalenone, deoxynivalenol (DON), T-2 toxin, neosolaniol, T-2 tetraol, wortmannin, and moniliformin were produced by the cultures on rice than on soybeans, but more HT-2 toxin was produced by one isolate ofF poae grown on soybeans than when grown on rice. Soybeans appear to be a poor substrate for elaboration of most of the toxins produced by the isolates tested.