Effect of concanavalin a on ganglioside metabolism of human lymphocytes

The effect of Con-A on the incorporation of radioactivity from [¹⁴C]-glucosamine into gangliosides of human lymphocytes was investigated. Compared with non-stimulated lymphocytes there was increased incorporation into gangliosides and total lipids within the first 24 hours of exposure to Con-A. Ganglioside synthesis also occurred in later time intervals within the 96 hour incubation period. GM3 accounted for 80% of the labeled ganglioside in Con-A stimulated cells at all times studied. Thus ganglioside synthesis is not only associated with cellular division, but also occurs within a few hours of lymphocyte activation representing an extremely early prereplicative event.     

Saprobic sequence within the genus euglena

In total 73 species of Euglena were ordered according to their saprobic index (S) and saprobic valency starting with species tolerating a heavy organic pollution and ending with those from most clean water. This paper is meant as an addition to the Ergebnisse der Limnologie, Heft 7 (Sládeek, 1973).     

The Effect of Temperature on the Fatty Acid Composition of Tetrahymena pyriformis WH-14

SYNOPSIS. A reduction in the growth temperature of Tetrahymena pyriformis strain WH-14 from 35 C to 15 C resulted in distinct alterations in the fatty acid composition of the glycerophospholipids. The proportion of normal saturated acids declined from 26 to 19%; palmitoleic acid increased by 6%, and the composition of the polyunsaturated fatty acids increased in 18:2 Δ^6,11(n) and decreased in 18:2 Δ^9,12(n) and 18:3 Δ^6,9,12(n). The unsaturation index (the average number of double bonds/100 molecules) did not change with a shift in temperature.
Two biosynthetic pathways exist in Tetrahymena for the formation of unsaturated fatty acids. The observed changes in fatty acid composition that accompany a lowering of the environmental temperature can be accounted for by a reduction in the accumulation of products of the fatty acid pathway leading to the formation of γ-linolenic acid [16:0(n) → 18:0(n) → 18:1 Δ⁹(n) → 18:2 Δ^9,12(n) → 18:3 Δ^6,9,12(n)] and an increase in the components of the pathway leading to the formation of 18:2 Δ^6,11(n) [16:0(n) → 16:1 Δ⁹(n) → 18:1 Δ¹¹(n) → 18:2 Δ^6,11(n)]. The data suggest that the regulatory mechanism in Tetrahymena differs from that found in some bacteria where a simple substitution of unsaturated fatty acids for saturated fatty acids occurs at low culture temperatures.     

Localization in the cell cycle of the antimitotic action of the pyrrolizidine alkaloid,lasiocarpine and of its metabolite,dehydroheliotridine

The antimitotic action of the pyrrolizidine alkaloid lasiocarpine on rat liver parenchyma was investigated using as the experimental model the wave of mitosis produced in liver by a single dose of thioacetamide. A single low dose of lasiocarpine administered two weeks before the thioacetamide, almost completely inhibited the mitotic wave without inhibiting to the same extent the preceding wave of DNA synthesis. By the use of selective inhibitors and radioisotope labelling, the location of the mitotic block was found to be either in the latter half of the DNA synthetic phase, S, or early in G₂, the post-synthetic phase. The mitotic wave was similarly inhibited by pretreatment of the rats with a single injection of dehydroheliotridine, a pyrrolic metabolite of heliotridine-based pyrrolizidine alkaloids.     

Comparison of species ordinations resulting from alternative indices of interspecific association and different numbers of included species

Summary Several measures of interspecific association are compared. Dispersion and covariance are limited in value because they respond to the commonness of the species compared. Correlation is not so limited but it responds to discrepancies in commonness among the species. The practical result of these relationships between commonness and association is that only the most common species can occupy periferal positions in a species ordination. Rare species are relegated to positions near the center not on the basis of their phytosociological pattern but simply because of their rarity. Both Cole's index of association and the tetrachoric correlation overcome the problem imposed by the relationship between ordination position and species commonness and they both produce very similar results. The effect of differing numbers of species on the ordination configuration is examined using both Pearson's correlation and Cole's index. The basic pattern of the ordination is set with the first few species when Cole's index is used, however, since rare species are given more weight in the analysis with this index, the addition of several very rare species can change the configuration of the ordination.Nomenclature of species is given in Table 1.Research supported by the Eastern Deciduous Forest Biome Project, US-IBP, funded by the National Science Foundation under Interagency Agreement AG-199, BMS69-01147 A09 with the Energy Research and Development Administration — Oak Ridge National Laboratory. Research also supported by the U.S. Energy Research and Development Administration under contract with the Union Carbide Corporation. Contribution No. 240 from the EDFB, US-IBP. Publication No. 790. Environmental Sciences Division, ORNL.     

Sex and side differences and correlations between quantitative palmar characteristics in a sample Sardinian population

Differences between the sexes and between the sides and the correlations between four quantitative characteristics of palmar dermatoglyphics in a sample population of 809 individuals (418 males and 391 females) from the city of Cagliari, Sardinia, are tested. Males have a greater number of ridges than females, shown by a greater a-b ridge count and A-d ridge count, and a more transverse slope of the main lines, shown by a greater main line index and papillary number. The left palm shows a greater number of ridges than the right palm between the A line and the triradius d and between the triradii a and b, with a lower main line index and papillary number. The a-b ridge count has a negative correlation with the main line index and with the papillary number and a positive one with the A-d ridge count; these correlations are greater in the left palms, especially in the males.     

Integrative assessment of Western Himalayas streams using multimeric index

Multimeric index based on fish composition was used to assess integrity of shallow and wadeable streams of lower Himalayas in temperate and subtropical ecoregions. Streams were surveyed for biotic and abiotic sampling during base flow periods in pre and post monsoon seasons in 2007 and 2008. Twenty three metrics were computed based on taxonomic richness, trophic composition, habitat preferences, abundance, stress tolerance and species origin attributes of 19 fish species. Candidate metrics were analyzed for efficiency to discriminate degraded sites from non-degraded and redundancy analysis, which sorted 71% of omnivore individuals (excluding intolerant species), 40% of intolerant individuals, 44% of herbivore individuals (excluding benthic species), abundance and 44.5% of non-native individuals as potential metrics. IBI values at forest, agriculture and urban zones were ranged between (max–min) 9.9–3.22, 6.18–2.49 and 4.43–0.69 respectively. Results suggested that poor ecological conditions in streams were generally related to drainage of urban sewage and habitat fragmentation while agriculture land use seems to have moderate impact on ecological integrity of the streams. Less urbanized upstream with grasslands and forests as land use, showed excellent to good ecological integrity of the streams. Proposed index was able to distinguish varying degrees of human impact on ecological integrity of streams and thus index could be used as valuable tool for bioassessment of regional flowing water resources.     

Modeling grassland aboveground biomass using a pure vegetation index

Remote sensing can be the most effective means of scaling up grassland aboveground biomass (AGB) from the sample scale to the regional scale. Among the remote-sensing approaches, statistical models based on the vegetation index (VI) are frequently used to retrieve grassland AGB because of their simplicity and reliability. However, these types of models have never been comprehensively optimized to overcome VI insensitivity and soil effects. Because grassland AGB is related to grassland type, in our research the integrated orderly classification system for grassland (IOCSG) was used to differentiate grassland types. The study area, located in Inner Mongolia, China, included desert steppe, typical steppe and meadow steppe. A pure VI (PVI) was extracted from the normal VI using spectral mixture analysis (SMA). Using a proportional relationship, PVI models were then constructed based on grassland type. The results demonstrated that the PVI models can have clear advantages over the more commonly used VI models. They simplify the parameterization of VI models and thus enhance models constructed for different regions with different remote sensing data sources. Notably, detailed differentiation of grassland types can improve the accuracy of AGB estimates. The methodology proposed in this study is particularly beneficial for AGB estimates at a national scale, especially for countries such as China with many grassland types.     

Condition and brightness of structural blue‐green: motmot tail‐racket brightness is related to speed of feather growth in males,but not in females

Coloration plays an important role in sexual and social communication, and in many avian species both males and females maintain elaborate colours. Recent research has provided strong support for the hypothesis that elaborate female traits can be maintained by sexual or social selection; however, most research on female ornamentation has focused on pigment‐based colours, and less is known about how structural colours are maintained. Both sexes of the turquoise‐browed motmot (Eumomota superciliosa) have a blue‐green racket‐tipped tail, and it remains unknown if tail coloration serves as a sexual or social signal in one or both sexes. Here, we describe sexual dichromatism in the blue‐green portion of the tail racket, and we test for a relationship between coloration and condition, as indicated by growth bars. Tail colour of both sexes has a similar spectral shape, and there is significant, although moderate, sexual dichromatism: males are brighter than females, and males have marginally greater blue‐green saturation than females. The length of feather grown per day is positively related to overall feather brightness, but this relationship is only present in males. The relationship between male coloration and condition suggests that tail colour has the potential to convey information about individual quality during mate choice or contest competition. The lack of a similar relationship in females suggests that female tail colour does not convey the same condition‐dependent information that we suggest may be reflected by male colour. Female tail colour may therefore reflect other aspects of condition, be involved in other (non‐condition‐dependent) forms of communication, or be expressed as a non‐functional byproduct of genetic correlation between the sexes. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 673–681.