Changes in the anatomical structure of tree rings of the rootstock and scion in the heterografts of Siberian pine

The analysis of the anatomical characteristics of tree rings of the Pinus sibirica scions and Pinus sylvestris rootstocks is presented. The main anatomical features maintain the seasonal dynamics characteristic of the reference (ungrafted) trees of scion and rootstock, pointing to the stability of the genetic control of the xylem differentiation. However, various anatomical characteristics are reduced for rootstocks and increased for scions relative to the reference trees. A mechanism consistent with our results is that the graft union zone creates a barrier for the ascending and descending transport of substances, including phytohormones. The reaction of the scion and rootstock to climatic factors is weakened relative to the reaction of the reference trees. Thus, the presumed shift towards phytohormone disbalance reduces the influence of external factors on xylem differentiation. The interannual variation of the individual characteristics of the scions and rootstocks is increased relative to the reference trees, reflecting either the influence of the graft partners on each other or the non-uniform distribution of the growth regulators across the graft union. Thus, heterografts can be used to evaluate the interaction of the internal and external mechanisms of xylem differentiation.     

The influence of sodium nitrite on the osmoresistance of Chinese hamster cells

We have previously demonstrated that incubation of V-79 cells in the medium containing the nitric oxide donor, NaNO2, increases cell resistance to damaging effect of gamma-rays, UV radiation and hyperthermia. In the present study, we investigated the effects of the nitric oxide donor on the sensitivity of V-79 cells to changes in osmomolarity of the medium by adding different amounts of sodium chloride or water. We found that pretreatment of the cells with NaNO2 resulted in a significant increase in the number of growing cells in 48 h after the treatment. The osmomolarity-dependent morphological changes in cultured cells were also substantially diminished following NaNO2 treatment. This effect could be observed under both hyper- and hypoosmosis, and was dependent on concentration of sodium chloride in hypertonic medium (being maximal under 0.17 M NaCl) and on the amount of water in hypotonic medium (being maximal under 1.1 times the dilution with water). In the experiments with increased osmomolarity, we found that the observed increase in the number of growing cells following NaNO2 treatment was accompanied with a significant increase of the mitotic index. These findings indicate that nitric oxide increases cell resistance to the damaging effects of osmotic shock in the way which is similar to the protective effect of these molecules against radiation and hyperthermia. Similarities in the effects of NaNO2 under different conditions leading to cell damage suggest that nitric oxide might serve as the universal factor participating in recovery of damaged cells and mediating increased cellular resistance to the damaging conditions.     

Fungicidal activity of cellobiose lipids from cultural fluid of yeast Cryptococcus humicola and Pseudozyma fusiformata

Cellobiose lipids of yeast fungi Cryptococcus humicola and Pseudozyma fusiformata have similar fungicidal activities against different yeast, including pathogenic Cryptococcus and Candida species. Basidiomycetic yeast reveals maximum sensitivity to these preparations; e.g., cells of cryptococcus Filobasidiella neoformans almost completely die after 30-min incubation in a glycolipid solution at a concentration of 0.02 mg/ml. The same effect toward ascomycetous yeast, including pathogenic Candida species, is achieved only at five to eight times higher concentrations of glycolipids. The cellobiose lipid from P. fusiformata, which, unlike glycolipid from Cr. humicola, has hydroxycaproic acid residue as O-subtituent of cellobiose and additional 15-hydroxy group in aglycone, inhibits the growth of the studied mycelial fungi more efficiently than the cellobiose lipid from Cr. humicola.     

Polysaccharides of algae: 60. Fucoidan from the pacific brown alga <Emphasis Type="Italic">Analipus japonicus</Emphasis> (Harv.) winne (Ectocarpales,Scytosiphonaceae)

A fucoidan containing L-fucose, sulfate, and O-acetyl groups at a molar ratio 3:2:1, as well as minor amounts of xylose, galactose, and uronic acids was isolated from the brown alga Analipus japonicus collected in the Sea of Japan. The structures of the native polysaccharide and the products of its desulfation and deacetylation were studied by the methods of methylation, periodate oxidation, and NMR spectroscopy. It was shown that a polysaccharide molecule mainly consists of a linear carbohydrate chain of (1→3)-linked α-L-fucopyranose residues, which bears numerous branches in the form of single α-L-fucopyranose residues (three branches at position 4 and one branch at position 2 per each ten residues of the main chain). Sulfate groups occupy positions 2 and (to a lesser extent) 4, most of the terminal nonreducing fucose residues being sulfated twice. The acetyl groups are located predominantly at positions 4. The structural role of minor monosaccharides was not established.     

A new subfamily LIP of the major intrinsic proteins

Background

Proteins of the major intrinsic protein (MIP) family, or aquaporins, have been detected in almost all organisms. These proteins are important in cells and organisms because they allow for passive transmembrane transport of water and other small, uncharged polar molecules.

Results

We compared the predicted amino acid sequences of 20 MIPs from several algae species of the phylum Heterokontophyta (Kingdom Chromista) with the sequences of MIPs from other organisms. Multiple sequence alignments revealed motifs that were homologous to functionally important NPA motifs and the so-called ar/R-selective filter of glyceroporins and aquaporins. The MIP sequences of the studied chromists fell into several clusters that belonged to different groups of MIPs from a wide variety of organisms from different Kingdoms. Two of these proteins belong to Plasma membrane intrinsic proteins (PIPs), four of them belong to GlpF-like intrinsic proteins (GIPs), and one of them belongs to a specific MIPE subfamily from green algae. Three proteins belong to the unclassified MIPs, two of which are of bacterial origin. Eight of the studied MIPs contain an NPM-motif in place of the second conserved NPA-motif typical of the majority of MIPs. The MIPs of heterokonts within all detected clusters can differ from other MIPs in the same cluster regarding the structure of the ar/R-selective filter and other generally conserved motifs.

Conclusions

We proposed placing nine MIPs from heterokonts into a new group, which we have named the LIPs (large intrinsic proteins). The possible substrate specificities of the studied MIPs are discussed.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-173) contains supplementary material, which is available to authorized users.     

Silicon nanotechnologies of pigmented heterokonts

Many pigmented heterokonts are able to synthesize elements of their cell walls (the frustules) of dense biogenic silica. These include diatom algae, which occupy a significant place in the biosphere. The siliceous frustules of diatoms have species-specific patterns of surface structures between 10 and a few hundred nanometers. The present review considers possible mechanisms of uptake of silicic acid from the aquatic environment, its transport across the plasmalemma, and intracellular transport and deposition of silica inside the specialized Silica Deposition Vesicle (SDV) where elements of the new frustule are formed. It is proposed that a complex of silicic acid with positively charged proteins silaffins and polypropylamines remains a homogeneous solution during the intracellular transport to SDV, where biogenic silica precipitates. The high density of the deposited biogenic silica may be due to removal of water from the SDV by aquaporins followed by syneresis--a process during which pore water is expelled from the network of the contracting gel. The pattern of aquaporins in the silicalemma, the membrane embracing the SDV, can determine the pattern of species-specific siliceous nanostructures.     

Quantifying how acquired interactions with native and invasive insects influence population growth rates of a non-indigenous plant

Non-native species often acquire novel interspecific interactions, which are central to several hypotheses of invasion success, including biotic resistance and invasional meltdown. However, the outcome of these interactions is not often linked with the demographic evidence based on the full life cycle of the species. The Philippine Ground Orchid (Spathoglottis plicata) has invaded Puerto Rico and has acquired both negative and positive interspecific interactions involving the native weevil Stethobaris polita and the invasive red fire ant Solenopsis invicta, respectively. We studied a population in the Rio Abajo Forest, and asked how these interactions affect population demography by using a combination of field, experimental and modelling approaches. Stage-structured matrix population models based on four years of field observations showed that the population of S. plicata is growing at a rate (λ) of 1.05 under natural conditions. When we modified fecundity values based on experimental exclusion of weevils and ants, the control treatment showed a similar λ. Excluding weevils increased λ to 1.20, whereas the exclusion of ants decreased λ to 1.03. When we incorporate demographic and environmental stochasticity in our models, exclusion of invasive red fire ants significantly reduces the orchid abundance over time. Although weevils offer some biotic resistance to S. plicata, these effects do not prevent orchid population growth and expansion. On the other hand, invasive red fire ants have a positive effect on the invasive orchid’s λ, partially supporting the invasional meltdown hypothesis. This study presents a method that allows one to combine opposing mechanisms of species interactions within the same quantitative framework, and the results highlight the importance of considering acquired plant–animal interactions and stochastic processes when evaluating the population growth rates and dynamics of invasive plants.