Intraspecific genetic variation of a Fagus sylvatica population in a temperate forest derived from airborne imaging spectroscopy time series

1. The growing pace of environmental change has increased the need for large‐scale monitoring of biodiversity. Declining intraspecific genetic variation is likely a critical factor in biodiversity loss, but is especially difficult to monitor: assessments of genetic variation are commonly based on measuring allele pools, which requires sampling of individuals and extensive sample processing, limiting spatial coverage. Alternatively, imaging spectroscopy data from remote platforms may hold the potential to reveal genetic structure of populations. In this study, we investigated how differences detected in an airborne imaging spectroscopy time series correspond to genetic variation within a population of Fagus sylvatica under natural conditions.
2. We used multi‐annual APEX (Airborne Prism Experiment) imaging spectrometer data from a temperate forest located in the Swiss midlands (Laegern, 47°28'N, 8°21'E), along with microsatellite data from F. sylvatica individuals collected at the site. We identified variation in foliar reflectance independent of annual and seasonal changes which we hypothesize is more likely to correspond to stable genetic differences. We established a direct connection between the spectroscopy and genetics data by using partial least squares (PLS) regression to predict the probability of belonging to a genetic cluster from spectral data.
3. We achieved the best genetic structure prediction by using derivatives of reflectance and a subset of wavebands rather than full‐analyzed spectra. Our model indicates that spectral regions related to leaf water content, phenols, pigments, and wax composition contribute most to the ability of this approach to predict genetic structure of F. sylvatica population in natural conditions.
4. This study advances the use of airborne imaging spectroscopy to assess tree genetic diversity at canopy level under natural conditions, which could overcome current spatiotemporal limitations on monitoring, understanding, and preventing genetic biodiversity loss imposed by requirements for extensive in situ sampling.

     

The distribution of living benthic foraminifera on the continental slope and rise off southwest Norway

Surface sediment samples taken by ? corer from 45 stations on the Norwegian continental margin and in the Norway Basin have been investigated for their benthic foraminiferal content. Unlike previous studies, the living benthic foraminiferal fauna was differentiated from empty tests comprising the foraminiferal death assemblage. Factor analysis of both the living and dead faunal data reveals six living species assemblages and five corresponding dead assemblages. The additional living assemblage is characterized by the arenaceous speciesCribrostomoides subglobosum that dominates between 1400 and 2000 m water depth, but is rare in the dead faunal data.Trifarina angulosa and, to a lesser extent,Cibicides lobatulus characterize the shallowest foraminiferal assemblage from 200 to 600 m water depth, where it is associated with strong bottom currents and warm, saline Atlantic water of the North Atlantic Drift. On the slope between 600 and 1200 m water depth, theMelonis zaandami Species Assemblage dominates, particularly in areas characterized today by rapid sedimentation of terrigeneous material. Between 1000 and 1400 m depth, where the slope is covered by fine grained, organic-rich, terrigeneous mud, the living foraminiferal assemblage is characterized byCassidulina teretis andPullenia bulloides. Below 1400 m, three foraminiferal assemblages are found:C. subglobosum is found from 1400 to 2000 m,Cibicidoides wuellerstorfi andEpistominella exigua predominantly live from 2000 to 3000 m water depth, and below 3000 m,Oridorsalis umbonatus andTriloculina frigida dominate the fauna.All of theElphidium excavatum tests found in this study and theCassidulina reniforme tests found above 500 m water depth were found to be reworked.Analysis of the sediment grain-size distribution and the organic carbon content in surface samples from the deepest stations suggest that the abundance ofC. wuellerstorfi andE. exigua is positively correlated to relatively coarse (caused by planktic foraminifera) and organic-rich sediments, whereas high frequencies ofO. umbonatus andT. frigida coincide with low organic carbon content. We suggest thatC. wuellerstorfi is adapted to deep-sea environments with relatively high food supply, tolerating relatively low interstitial water oxygen content, whereasO. umbonatus may tolerate lower food supply prefering well-oxygenated interstitial waters.     

Growth-related expression of a double-stranded RNA-dependent protein kinase in 3T3 cells

Cultured mouse 3T3-F442A and 3T3-C2 fibroblasts exhibit a transient double-stranded RNA (dsRNA)-dependent phosphorylation of a 67,000-dalton protein (67K) without prior treatment with interferon (IFN). This phosphoprotein is similar but not identical to the dsRNA-dependent eukaryotic initiation factor-2 (eIF-2) alpha protein kinase (dsI), which regulates protein synthesis in rabbit reticulocytes. We have studied the relationship between cell growth and phosphorylation of the 67K protein (designated 3T3-dsRNA-dependent eIF-2 alpha kinase). A low level of dsRNA-dependent phosphorylation of 3T3-dsI was detectable in extracts prepared from cells not treated with IFN and grown at a low cell density. The phosphorylation of dsI and the phosphorylation of a 38K protein identified as the alpha-subunit (38K) of 3T3-eIF-2 (eIF-2 alpha) occurred concomitantly; the levels of these phosphorylations confluent and thereafter decreased markedly. Treatment of cells with IFN at all stages of growth resulted in an increase in phosphorylation of dsI. 3T3-F442A and 3T3-C2 fibroblasts were found to produce and secrete IFN at levels sufficient to induce an elevated dsI activity.     

Raman and infrared spectra of toxin gamma from the venom of the scorpion Tityus serrulatus

Toxin gamma is a basic, low-molecular-weight, neurotoxic protein, isolated from the venom of the Brazilian scorpion, Tityus serrulatus. Raman spectra (400-1800 cm-1 region) of this toxin in both the lyophilized state and in 0.1 M acetate buffer (pH 4.5) and the infrared spectrum (700-4000 cm-1 region) of a solid film were investigated. From the vibrational spectra, it can be concluded that the polypeptide backbone of toxin gamma consists of a mixture of the different secondary structures, with predominance of beta-sheet, followed by unordered structure and alpha-helix, with some evidence of beta-turn structures. The four disulfide bridges assume the gauche-gauche-gauche conformation of the CCSSCC fragments. The intensity ratio of the doublet at 853 and 828 cm-1 suggests that four out of the five tyrosine residues are exposed. The three tryptophan residues are exposed on the surface, and the single methionine residue assume the gauche-gauche conformation. Toxin gamma retains full activity in the pH 4.5-7.5 range, but is almost completely inactivated at pH 11.5.     

The inhibition of phospholipase A2 by manoalide and manoalide analogues

Manoalide, a natural product from sponge, displays anti-inflammatory activity in vivo. Previous work has shown that manoalide is also a potent covalent inhibitor of the extracellular phospholipase A2 from cobra venom and that the inhibition correlated with a pH-dependent change in manoalide (Lombardo and Dennis (1985) J. Biol. Chem. 260, 7234-7240). Manoalide contains two rings and the opening of either would produce an alpha,beta-unsaturated aldehyde. The cobra venom phospholipase A2 may be able to catalyze the opening or isomerization of one of these rings, raising the possibility that manoalide is acting as a suicide substrate. To ascertain the role of the gamma-lactone ring in the inhibition, we have now investigated a synthetic manoalide analogue, 3(cis,cis-7,10)-hexadecadienyl-4-hydroxy-2-butenolide (HDHB) which contains only the alpha,beta-unsaturated gamma-lactone ring. We have found that the closed and open forms are in rapid equilibrium between pH 4 and 9 with the cyclic form being preferred at acidic pH values and the open cis form preferred at pH 9.5. When the pH is raised above 12, the alpha,beta double bond isomerizes to form trans-HDHB. Once the trans compound is formed, it is stable at all pH values and does not recyclize to the gamma-lactone ring. The observed pKa of 7.7 found for the inhibition of manoalide agrees well with the transition of the closed to the cis form of the gamma-lactone ring. Kinetic experiments with the HDHB compound show that under conditions in which the cis and closed form of the inhibitor are present in equal molar ratios, HDHB is not an irreversible inhibitor, but reversibly competes with substrate. However, the kinetics of this inhibition are complex and do not follow either pure competitive or non-competitive inhibition. The trans-HDHB exhibits similar complex kinetic but is several times more potent. The distinct differences between the behavior of manoalide and HDHB clearly indicate that while the gamma-lactone ring may play an important role in manoalide inhibition, it alone does not produce irreversible inhibition.     

Immunological characterization of cytochrome H-450 in rat tissues

Rabbit antiserum produced against rat liver cytochrome H-450 was specific for cytochrome H-450. The antiserum did not react with hemolysate, microsomal and mitochondrial fractions of liver, and tissue extracts from heart, lung skeletal muscle, and testis of rat. With the monospecific antiserum, a rocket immunoelectrophoretic assay method was developed for the quantitation of the antigen with a sensitivity of 25 ng. By using rocket immunoelectrophoresis, the total amounts of the antigen found in liver, kidney, and brain of 20 rats were 33.6, 3.6, and 1.3 mg, respectively. It appears that the antigens in liver, kidney, and brain are immunologically identical. From immunological studies with subcellular fractions of rat liver, the antigen was found only in the postmicrosomal fraction. This indicates that the antigen is not a precursor or a proteolytic product of known cytochromes in mitochondria or microsomes. Therefore, cytochrome H-450 is a unique cytosolic protein found in brain, kidney, and liver.     

Potent inhibitory effects of the 5'-triphosphates of (E)-5-(2-bromovinyl)-2'-deoxyuridine and (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil on DNA polymerase gamma

(E)-5-(2-Bromovinyl)-2'-deoxyuridine 5'-triphosphate (BrVdUTP) and (E)-5-(2-bromovinyl)-1-beta-D-arabinofuranosyluracil 5'-triphosphate (BrVarafUTP), which are known as specific inhibitors of herpes simplex viral (type 1 and 2) DNA polymerase, were found to be strong inhibitors of DNA polymerase gamma from human KB and murine myeloma cells. In fact BrVdUTP and BrVarafUTP were found to be stronger inhibitors of DNA polymerase gamma than of other DNA polymerases having viral (herpes simplex virus or retrovirus) origin or cellular (eukaryotic alpha and beta, or prokaryotic) origin. The mode of inhibition of DNA polymerase gamma by BrVdUTP and BrVarafUTP was competitive with respect to dTTP, the normal substrate. Whereas BrVdUTP was an efficient substrate for DNA polymerase gamma and other DNA polymerases that were examined, BrVarafUTP failed to serve as a substrate for DNA synthesis. Ki values for BrVdUTP (40 nM) and BrVarafUTP (7 nM) with DNA polymerase gamma, as determined with (rA)n.(dT) as the template.primer, were much smaller than the Km values for dTTP (0.16 microM and 0.71 microM for murine and human DNA polymerase gamma, respectively). Thus, the affinity of BrVdUTP or BrVarafUTP for DNA polymerase gamma was much stronger than that of dTTP.     

Organic-solvent water pollution and low birth weight in Michigan.

This pilot study explored the association between a measure of water pollution caused by benzene or chlorinated solvents and the incidence of low birth weights for white residents of Michigan counties. A positive relationship between water pollution by these contaminants and the per cent of low-weight births (less than 2,500 grams, or about 5.5 pounds) resulted despite controls for the incidence of teenaged childbearing, infrequent prenatal care, and mean household income from wages or salaries. Water pollution showed an association with the incidence of low birth weight that was as strong as that between low birth weight and low prenatal care. While correlation cannot prove causation, the finding suggests that impure water may impair fetal growth in Michigan.