Analysis of primary food sources and trophic relationships of aquatic animals in a mangrove-fringed estuary,Khung Krabaen Bay (Thailand) using dual stable isotope techniques

Stable carbon (¹³C) and nitrogen (¹⁵N) isotopes were used to elucidate primary food sources and trophic relationships of organisms in Khung Krabaen Bay and adjacent offshore waters. The three separate sampling sites were mangroves, inner bay and offshore. The ¹³C values of mangrove leaves were –28.2 to –29.4, seagrass –10.5, macroalgae –14.9 to –18.2, plankton –20.0 to –21.8, benthic detritus –15.1 to –26.3, invertebrates –16.5 to –26.0, and fishes –13.4 to –26.3. The ¹⁵N values of mangrove leaves were 4.3 to 5.7, seagrass 4.3, macroalgae 2.2 to 4.4, plankton 5.7 to 6.4 , benthic detritus 5.1 to 5.3, invertebrates 7.2 to 12.2 , and fishes 6.3 to 15.9. The primary producers had distinct ¹³C values. The ¹³C values of animals collected from mangroves were more negative than those of animals collected far from shore. The primary carbon sources that support food webs clearly depended on location. The contribution of mangroves to food webs was confined only to mangroves, but a mixture of macroalgae and plankton was a major carbon source for organisms in the inner bay area. Offshore organisms clearly derived their carbon through the planktonic food web. The ¹⁵N values of consumers were enriched by 3–4 relative to their diets. The ¹⁵N data suggests that some of aquatic animals had capacity to change their feeding habits according to places and availability of foods and as a result, individuals of the same species could be assigned to different trophic levels at different places.     

Carotenoids from plankton and photosynthetic bacteria in sediments as indicators of trophic changes in Lake Lobsigen during the last 14000 years

Previous examination of drilling cores showed that the majority of the carotenes and carotenoids originally present in the various planktonic organisms and phototrophic bacteria are preserved in sediments. The indicator pigments for algae phyla are: Lutein for Chlorophyta, Myxoxanthophylls and their derivatives for Cyanophyta, Fucoxanthin for Chrysophyta, and Alloxanthin for Cryptophyta.The pigments in the deepest sediment sample (late glacial time, clay, 12.83 m) consists primarily of Alloxanthin, secondly of Lutein and -carotene and thirdly of traces of Okenone, Speroidenone and other such bacterial carotenoids. The first plankton organisms were thus Cryptophyta and some Chlorophyta. The presence of the phototrophic bacteria pigments indicates that at the time of sediment formation, anaerobic conditions prevailed at the lake bottom.The Holocene era commences at a depth of 8.55 m and is characterized by the first occurrence of Myxoxanthophyll and Echinenone from Cyanophyta, as well as by a rapid increase of -carotene, Lutein and Alloxanthin. The pronounced occurrence of Oscillatoria rubescens (blood of the Burgundies), characterized by Oscillaxanthin at 8.21 m must be considered for Swiss lakes as a very surprising discovery.The intensive plankton production again lead to stringent anaerobic conditions. Predominant among phototrophic bacteria pigments were Okenone, Spheroidene and Rhodopin.     

Evaluation of community indices in seasonal assemblages of butterflies (Lepidoptera) at different frequency of transect count

Community indices were evaluated at different frequency of transect counts of butterflies by randomization. Randomized samples were obtained by re-arranging 1, 3, 6, 12 and 18 counts from 18 counts at a study site (Hiraoka), and 1, 2, 3, 5 and 15 from 15 at another site (Narukawa), in 1994. Morisita's new estimate of species richness, QM gave a good estimate when the number of counts was five or more. QM estimated from the sum of both assemblages (58 species) was 70.7, while 73 species were recorded at least once from 1990 to 1994. The Octave method always resulted in an underestimation. Diversity indices, Shannon's H, Simpson's D and , Hurlbert's E(Sn), Itow's b, and Morisita's H gave good estimates when the number of counts was five or more. Temporariness of univoltine species in flight period made a bias in the estimates. We concluded that the count is needed at least six times (once a month) and the estimates were improved by separating the multivoltine species from the univoltine species. Intensive counting during the flight period of the univoltine species was recommended.     

The reduction of tetrazolium salts by plant mitochondria

Summary Data has been obtained concerning the reduction of tetrazolium salts by mitochondria isolated from Jerusalem artichoke tubers with succinate as the substrate using a direct recording spectrophotometric method of assay. ATP was found to increase the rate of reduction of the tetrazolium salts, this being independent of the effect ATP had on the rate of oxygen uptake. The magnitude of the stimulation by ATP depended on the concentration of tetrazolium salts present and under certain circumstances was suppressed by the addition of azide and cyanide. The sites at which the tetrazolium salts were reduced along the electron transport chain were investigated. The role of ATP has been discussed in relation to the mechanism of tetrazolium reduction.Abbreviations TTC 2,3,5-triphenyl-2,1,3,4-tetrazolium chloride - BT 5,5-diphenyl-3,3-(3,3-dimethoxy-4,4-diphenylene)-ditetrazolium chloride - NT 2,2,5,5-tetraphenyl-3,3-(p-diphenylene)-ditetrazolium chloride - MTT 3-(4,5-dimethyl thiozolyl-2)-2,5-diphenyl tetrazolium bromide - INT 2-(p-iodophenyl)-3-p-dinitrophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride - NBT 2,2-dinitrophenyl-5,5-diphenyl-3,3-dimethoxy-4,4-diphenylene)-ditetrazolium chloride - TNBT 2,2-5,5-tetra-p-nitrophenyl-3,3-dimethoxy-4,4-diphenylene) ditetrazolium chloride     

The plankton of the tropical western Indian ocean as a biomass indirectly supporting surface tunas (yellowfin,Thunnus albacares and skipjack,Katsuwonus pelamis)

Synopsis The biomass of available forage is a key factor in controlling the abundance and distribution of surface tropical tunas, as they have high energy demands and live in a poor environment. The direct estimate of this forage biomass is not possible with existing techniques. Thus we have investigated the lower link, i.e. the plankton organisms which are the food of fishes preyed upon by tunas. In a previous study, this fraction of the zooplankton has been identified, both by taxa and by size, by analysing the stomach contents of the fishes which are the preys of tunas. In this paper, we use 331 plankton samples from tuna fishing grounds of the tropical Indian ocean, to define the characteristics of the planktonic fraction actually participating in the tuna food chain. Main results are as follows: (1) Only 15–27 % of the total zooplanktonic biomass (> 1 mm) is actually accessible for the fishes preyed upon by surface tunas. This useful part of the zooplankton is a well defined fraction of the planktonic population which remains in the 0–170 meters water layer during daylight hours. This part of the zooplankton accounts for a variable percentage of its total biomass the different geographic areas and represents the most relevant parameter to assess the potential richness of a given area for surface tunas. (2) From areas where fishing for surface tunas is poor to those where fishing is successful, it is observed that the total zooplankton biomass increases by a factor of 4 whereas the biomass of the useful fraction increases by a factor of 7. This disproportionate increase is due to the facts that the potential preys of fishes preyed upon by tunas represent a growing fraction of the zooplankton and that a growing proportion of this fraction remains by day in the 0–170 meter water layer, therefore becoming available for the day-feeders which comprise most of the prey-fishes of surface tunas.     

Tit-For-Tat in guppies (Poecilia reticulata): the relative nature of cooperation and defection during predator inspection

Summary The introduction of game-theoretical thinking into evolutionary biology has laid the groundwork for a heuristic view of animal behaviour in which individuals employ strategies — rules that instruct them how to behave in a given circumstance to maximize relative fitness. Axelrod and Hamilton (1981) found that a strategy called Tit-For-Tat (TFT) is one robust cooperative solution to the iterated Prisoner's Dilemma game. There exists, however, little empirical evidence that animals employ TFT. Predator inspection in fish provides one ecological context in which to examine the use of the TFT strategy.Here we describe a study in which guppies were tested in multiple predator inspection trials. An individual was tested with its mirror images as well as a series of live conspecifics. Results indicate that guppies are capable of recognizing and remembering their partner's behaviour and seem to employ TFT-like strategies over the course of many inspection visits. In addition, significant differences exist between individuals in the degree to which they will inspect a predator, suggesting that cooperator and defector may be relative terms rather than discrete categories of behaviour.     

Genetic studies of frost resistance in wheat

Summary Genetic studies of frost resistance were performed on various wheat varieties using diallel, F₂ monosomic and substitution analysis.A six-parental cross including reciprocals was carried out, and F₁ hybrids and their parents were used for the freezing tests under controlled conditions. Both the general combining ability (GCA) and the specific combining ability (SCA) were significant, indicating additive and non-additive gene action in the inheritance of frost resistance. The high GCASCA ratio revealed a preponderance of additive genetic variance. No significant reciprocal differences were found between the reciprocal crosses. The variance/covariance graphical analysis indicated the partial dominance of frost sensitivity. Frost sensitive varieties had the largest number of dominant genes, while frost resistant varieties had the highest proportion of recessive genes. The magnitude of the additive component of variation was higher than that of the dominance component, and the overall measure of the degree of dominance was smaller than one, so average dominance is incomplete. The increasing and decreasing alleles are not equally frequent at all loci. In this set of wheat varieties the values of narrow and broad heritability are relatively high.F₂ monosomic analysis of the winter wheat variety Arthur crossed with the monosomics of Chinese Spring revealed that the average frost resistance of all the 21 monosomics was lower than that of the disomic. F₂ monosomic hybrids 5A, 2B, 4B and 5D proved to be relatively frost resistant, while monosomics 3A, 3B and 6D were the most sensitive.The control of frost resistance in the set of chromosome substitution lines of the variety Cheyenne into Chinese Spring (with the exception of 2B) indicated that the genes responsible for the frost resistance of Cheyenne are localised in chromosomes 5A, 7A, 4B, 5B, 4D and 5D.The genetic basis of frost resistance and problems of analysis are discussed.     

Possible complex translocation t(9; 14; 13)(q12;pl?;q31) in mother of a child with 9p-trisomy syndrome

Summary A mentally retarded boy with trisomy 9p is described. This trisomy arose through aberrant segregation of translocation chromosome during meiosis in his mother, who has a complex translocation involving chromosomes 9, 13, and 14. Based on both G-, Q-banding, and DNA replication patterns, the patient's karyotype was identified as 47,XY,-13, +(9;13) (9pter9q12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter). We suppose his mother's karyotype to be 46,XX,-9,-13,-14,+t(9;13) (9pterq12::13q3113qter), +t(13;14) (13pter13q31::14pl?14pter), +t(9;14) (9qter9q12::14pl?14qter). His phenotypically normal brother and sister are also carriers, having the same translocation chromosome as their mother. Clinical findings of the patient included peculiar face with hypertelorism, prominent nasal bridge and deformed helix, marked delay of osseous development, hypoplastic phalangia in fingers and toes, dysplastic nails and absence of digital triradii.     

The dynamic effects of inputs to spinal motoneurones of different type upon the outputs of γ-motoneurones mediated via recurrent inhibition

A previous dynamic model of the spinal motoneurone-Renshaw cell system has been extended by integrating -motoneurones (-MNs), which are also supposed to represent Ia inhibitory interneurones mediating reciprocal inhibition. For the recurrent inhibition of -MNs, two cases are considered: -MNs inhibiting themselves via Renshaw cells (RCs), and -MNs not subjected to self-inhibition. Two input systems are taken into account: monosynaptic Ia input distributed inhomogeneously to the three types of -MNs (S, FR, and FF), and spinally descending input from the lateral vestibular nucleus distributed inhomogeneously to the three -MN types and to -MNs. Dynamic input-output relations have been calculated in form of Bode or polar plots. The main results are: Input signals (Ia and VST) to -MNs are transmitted via RCs to -MNs with high-pass characteristics (lower cut-off around 1 Hz). The relatively high gains at high frequencies are attenuated more or less strongly by recurrent self-inhibition of -MNs depending on the overall strength of recurrent inhibition. The phase lags of -MNs with respect to the input are not frequency-independent, but vary between about-90° and-180° (at times up to-200°). To preserve in-phase activation of -and -MNs, certain criteria have to be met which are discussed in terms of additional input systems to -MNs and RCs.     

Association of acid-producing thiobacilli with degradation of concrete: analysis by ‘signature’ fatty acids from the polar lipids and lipopolysaccharide

Summary The acid-producing thiobacilli contain fatty acid components in the polar lipids and lipopolysaccharide lipid A that are sufficiently unusual that they can be utilized as signature lipid biomarkers for these organisms in environmental samples. Studies in microcosms have shown correlations between activity of these organisms, measured by recovery and viable counting, and the degradation of concrete. The signature lipid analysis provides a detection assay requiring neither separation of the organisms from the substratum nor growth prior to determination. The presence of acid-producing thiobacilli was demonstrated in microcosm samples and degenerating concrete from the Hamburg (F.R.G.) sewer system.     

“It Ain’t Over ‘til it’s Over”: Rethinking the Darwinian Revolution

This paper attempts a critical examination of scholarly understanding of the historical event referred to as the Darwinian Revolution. In particular, it concentrates on some of the major scholarly works that have appeared since the publication in 1979 of Michael Ruses The Darwinian Revolution: Nature Red in Tooth and Claw. The paper closes by arguing that fruitful critical perspectives on what counts as this event can be gained by locating it in a range of historiographic and disciplinary contexts that include the emergence of the discipline of evolutionary biology (following the evolutionary synthesis), the 1959 Darwin centenary, and the maturation of the discipline of the history of science. Broader perspectives on something called the Darwinian Revolution are called for that include recognizing that it does not map a one-to-one correspondence with the history of evolution, broadly construed.     

Biochemical identification and immunological localization of two non-keratin polypeptides associated with the terminal differentiation of avian scale epidermis

Summary The expression of two previously uncharacterized polypeptides produced in epidermal cells of chick reticulate and scutate scales during late embryonic scale histogenesis and in hatchling birds has been studied biochemically and immunologically. These polypeptides have been identified by two-dimensional pH gradient gel electrophoresis as basic in charge, with apparent molecular weights of 20 and 23 kD, and they have been characterized immunologically and by amino acid analysis as non-keratin in nature. Monoclonal antibodies which react with both polypeptides have been used for immunohistochemical and immunogold electron-microscopic localization. Immunoreactivity was observed in suprabasal cells of reticulate scale epidermis, where it codistributed with bundles of -type cytokeratins in the -keratin-rich layers of epidermis known as the alpha stratum and in suprabasal cells of the outer epidermal surface of scutate scales, where it codistributed with -and -type keratin filament bundles in the -keratin-rich layers of epidermis known as the beta stratum.     

The long,the short and the stalled: on the attributes of phytoplankton selected by physical mixing in lakes and rivers

Paradoxically, although turbulence characterises the open water environments of planktonic organisms in lakes, rivers and seas, most species of phytoplankton are smaller than the size of the smallest eddies dissipating the energy and, so, must function in an immediate medium which is inherently viscous. Intensively mixed systems, such as wind-stirred shallow lakes, rivers and estuaries, however, constantly readjust the vertical position of suspended algae and, often, other non-living, light-absorbing particles with the effect that the light field to which the algae are subject is erratic and the received day-time light dose is aggregately depressed: cells need to photoadapt accordingly. In fluvial environments the additional constraint of rapid, horizontal, supposedly unidirectional, transport is applied, requiring the attribute of rapid processing of primary products and cell replication. Significant downstream recruitment, however, is benefitted by the presence of so-called dead-zones which retain water (and suspended plankton) sufficiently to accommodate additional cell divisions.     

Trophic interactions of Antarctic seals as determined by stable isotope signatures

The diets and trophic interactions among Weddell, crabeater, Ross, and leopard seals in the eastern Ross Sea, Antarctica, were investigated by the use of stable isotope techniques during the 1999–2000 summer seasons. The ¹³C and ¹⁵N values in seal serum clearly distinguished the three Antarctic pack-ice seal species at different trophic positions (Weddell>Ross>crabeater). These patterns appeared to reflect a close linkage to their known foraging ecology and diving behaviors, and agreed well with their presumed dietary diversity. The more enriched ¹³C and ¹⁵N values in male Weddell seals than those in females suggested differences in foraging preferences between them. Significant differences in ¹⁵N were also found among different age groups of Weddell seals. A strong correlation between the C:N ratios and serum cholesterol was probably due to extremely high cholesterol levels in phocids. Comparisons of isotope data with harbor seals revealed distinct differences between Antarctic phocids and the northern seal species.     

SSCP detection of a Gly565Val substitution in the proα(I) collagen chain resulting in osteogenesis imperfecta type II

A patient with perinatal lethal osteogenesis imperfecta (OI) type II has been studied in order to identify the causative mutation. By analysis of the type I collagen produced by cultured fibroblasts from the patient, the defect was mapped to 1 cyanogen bromide peptide 7, a region corresponding to 271 amino acid residues of either the 1(I) or 2(I) collagen chains. Polymerase chain reaction (PCR) amplification of the corresponding region of the 1(I) mRNA followed by single-strand conformation polymorphism analysis of restriction enzyme digestions of the PCR products allowed further mapping of the mutation to a small region of COL1A1. A heterozygous transversion of G to T within the last glycine codon of exon 32 was identified by DNA sequence analysis. This resulted in the substitution of glycine-565 by a valine residue, disrupting the repeating Gly-Xaa-Yaa sequence that is obligatory for correct formation of the collagen molecule. The mutation was shown to have occurred de novo and is thought to result in the OI phenotype.     

The role of knowledge and spatial contexts in biodiversity policies: a sociological perspective

In policy processes, biodiversity has been broadened into a holistic notion uniting a variety of cultural, social and economic issues with the biological conservation issue. Therefore, the formation of biodiversity conservation into concrete policy goals appears rather difficult. In this paper, we aim to explore the political implications and consequences of the strong dependency on science of the biodiversity issue. Concentrating especially on environmental policy options, we also examine the globalization and localization processes in the case of biodiversity. In spite of several controversial features and of an evident lack of knowledge on biological diversity, the issue undoubtedly has significant political strengths. However, from the viewpoint of research on environmental policies, the role of scientific knowledge in decision making should be recognized as an open empirical question depending on the concrete contexts of the decision-making process. Further, it is concluded that the concepts relating to global environment are objects of a continuous localization. Thus, any moral-technocratic solutions emphasizing simply universal interests as the basis for global biodiversity management must be met with caution. In future research there is a need for concrete case studies in order to clarify the local conditions and opportunities of biodiversity policies.     

Complete protection against melanoma in absence of autoimmune depigmentation after rejection of melanoma cells expressing α(1,3)galactosyl epitopes

The major barrier for xenotransplantation in humans is the presence of (1–3) Galactosyl epitopes (Gal) in xenogeneic tissue and the vast quantities of natural antibodies (Ab) produced by humans against this epitope. The binding of anti-Gal Ab to cells expressing Gal triggers a complement-mediated hyperacute rejection of target cells. The hyperacute rejection of whole cancer cells, modified to express Gal epitopes, could be exploited as a new cancer vaccine to treat human cancers. We tested this hypothesis in Galactosyltransferase knockout (GT KO) mice which, like humans, do not express Gal on their cell surfaces and can produce anti-Gal Ab. Forty-five percent of mice with preexisting anti-Gal Ab rejected Gal positive melanoma cells (B16Gal). These mice remained tumor-free for more than 90 days. The majority of control mice injected with B16Null, Gal negative cells succumbed to melanoma. The rejection of B16Gal induced strong long-lasting antitumor immunity against B16Null measured by the expansion of cytotoxic T lymphocytes. In addition, mice rejecting B16Gal were protected against melanoma since they survived a second rechallenge with B16Null. Protected mice developed antitumor immunity in the absence of autoimmune depigmentation (vitiligo). These results show that rejection of Gal positive melanoma cells can efficiently boost the immune response to other tumor associated antigens present in Gal negative melanoma cells. This study supports the concept of a novel anticancer vaccine to treat human malignancies.     

Empirical relationships between cladoceran fauna and trophic state in thirteen northern German lakes: analysis of surficial sediments

The cladoceran faunas from 13 northern German lakes (the Plön district) of different trophic levels were analysed using the bosminid and chydorid remains in the surficial sediment as an integrated sample of the total lake fauna. In the dimictic lakes, a shift occurred in the composition of planktonic Cladocera from Bosmina coregoni, including morphs with a mucro, to predominance of Chydorus sphaericus and Bosmina c. thersites as trophic state increased. In the benthic Cladocera (Chydoridae), there was a decrease in species diversity, in the percentages of phytophilous species and in the portion of species that are typical of clear water lakes, but there was an increase both in the number of mud dwellers and species that are typical of polluted lakes. No positive correlation was found between mean depth of the lakes and the planktonic/littoral ratio.     

Inversion of ‘fluorescent’ segment in chromosome 3: A polymorphic trait

Summary The frequency of the inversion of fluorescent constitutive heterochromatin in chromosome 3 was the same in a sample of 370 retarded persons as in a sample of 222 mentally normal men. It can be concluded that this inversion is not associated with mental retardation. This variant is more common (4%) in the Canadian population we studied than in samples reported by most other authors (0–1.7%). Possibly the founder effect could play a role in the differences. Two cases of homozygotes for this inversion were identified.     

Conformational dynamics of the anticodon loop in yeast tRNAPhe as sensed by the fluorescence of wybutine

Conformational and dynamic properties of the anticodon loop of yeast tRNA^Phe were investigated by analyzing the time resolved fluorescence of wybutine serving as a local structural probe adjacent to the anticodon GmAA on its 3 side. The influence of Mg²⁺, important for stabilizing the tertiary structure of tRNA, and of the complementary anticodon s²UUC of E. coli tRNA ₂ ^Glu were investigated.Fluorescence lifetimes and anisotropies were measured with ps time resolution using time correlated single photon counting and a mode locked synchronously pumped and frequency doubled dye laser as excitation source. From the analysis of lifetimes () and rotational relaxation times ( _R ) we conclude that wybutine occurs in various structural states: (i) one stacked conformation where the base has no free mobility and the only rotational motion reflects the mobility of the whole tRNA molecule (=6 ns, _R =19 ns), (ii) an unstacked conformation where the base can freely rotate (=100 ps, _R = 370 ps) and (iii) an intermediary state (=2 ns, _R = 1.6 ns).Under biological conditions, i. e. in the presence of Mg²⁺ and neutral salts, wybutine is found in a stacked and immobile state which is consistent with the crystallographic picture. In the presence of the complementary codon however, as exemplified by the E. coli-tRNA ₂ ^Glu anticodon, our analysis indicates that the codon-anticodon complex exists in an equilibrium of structural states with different rotational mobility of wybutine. The conformation with wybutine freely mobile is the predominant one and suggests that this conformation of the codon-anticodon structure differs from the canonical 3–5 stack.