Macromutations and evolution: fixation of Goldschmidt's macromutations as species and genus characters. Papillomatosis and appearance of macrovilli in the rodent stomach

The cardiac portion of the stomach is lined with macrovilli in a few rodent genera. These are Mystromys (Cricetinae, Cricetidae), Myospalax (Myospalacinae, Cricetidae), Tachyoryctes (Tachyoryctinae, Cricetidae), and Cryptomys (Bathyergidae). The macrovilli favor the development of symbiotic flora and are called symbiovilli. Growth of the corneal epithelium of the cardiac portion of the stomach serves as a morphological basis of symbiovilli. Cases of a hereditary malignant neoplasm giving rise to the formation of multiple macrovilli in the cardiac portion of the stomach have been found in Microtus abbreviatus (Microtinae, Cricetidae), a vole endemic to St. Matthew Island in the Bering Sea. The macrovilli resulting from the papillomatosis mutation are morphologically and histologically identical to the macrovilli of the stomach of the four aforementioned genera. The voles affected with papillomatosis still survive long enough to reproduce. Therefore, the macromutation that leads to death in adult and old voles has been fixed as a species character in some rodent genera. At the early stages of papillomatosis, the pathogenic morphogenesis creates favorable conditions for the development of symbiotic microflora, which gives a selective advantage to the affected animals. It is assumed that mutations with pathogenic effects have been fixed as a species character as a result of heterochrony. The pathogenic neoplasm serves as a preadaptation for the growth of symbiotic flora in the stomach. The mechanisms of the fixation of Goldschmidt's "systemic mutations" during phylogeny are discussed.     

Different demography of friends and strangers: an experiment on the impact of kinship and familiarity in Clethrionomys glareolus

Summary We examined demographic effects of familiarity and relatedness in the bank vole Clethrionomys glareolus (Schreber) in four 0.5-ha enclosures in Central Finland. In two enclosures were mature voles which had overwintered together and some of their mature off-spring (hereafter referred to as Friends), and in the other two individuals of the same species captured from different localities near the study area (Strangers). The experiment lasted from June to September. The populations of Friends reached densities twice as high as those of Strangers with a significantly higher rate of recruitment and survival of the young. This may have been due to mutual familiarity decreasing antagonism towards the juveniles. The conflicting results obtained from studies of Clethrionomys and Microtus are discussed. We believe that these genera represent behavioural adaptations to different habitats and ways of life. Most behavioural population regulation hypotheses are based on studies of Microtus. We conclude that these results should be applied with great caution to other rodent genera.     

Uptake of phosphate by symbiotic and free-living dinoflagellates

Uptake of phosphate in the light by Amphidinium carterae, Amphidinium klebsii, cultured and symbiotic Gymnodinium microadriaticum conformed to Michaelis-Menten type saturation kinetics with all organisms showing similar K _m values, namely 0.005 to 0.016 M phosphorus. V _max values were 0.009–0.32 nmol phosphorus · 10⁵ cells^-1 · 10 min^-1. Phosphate uptake by all the dinoflagellates was greater in the dark than in the light. The metabolic inhibitor 3-(3,4-dichlorophenyl) 1,1-dimethylurea stimulated phosphate uptake in the light by A. carterae and A. klebsii, but inhibited uptake by cultured and symbiotic G. microadriaticum. Carbonylcyanide 3-chlorophenylhydrazone (CCCP) inhibited phosphate uptake by A. carterae and A. klebsii under both light and dark conditions. Uptake of phosphate by cultured and symbiotic G. microadriaticum in the light, but not in the dark, was inhibited by CCCP. Low concentrations of arsenate (5 g As · l^-1) stimulated phosphate by A. carterae and A. klebsii, but inhibited uptake by cultured and symbiotic G. microadriaticum. High concentrations of arsenate (100 g As · l^-1) did not affect uptake of phosphate by A. carterae and A. klebsii.     

Diversity,metabolic types and δ13C carbon isotope ratios in the grass flora of Namibia in relation to growth form,precipitation and habitat conditions

The grass flora of Namibia (374 species in 110 genera) shows surprisingly little variation in ¹³C values along a rainfall gradient (50–600 mm) and in different habitat conditions. However, there are significant differences in the ¹³C values between the metabolic types of the C4 photosynthetic pathway. NADP-ME-type C4 species exhibit the highest ¹³C values (–11.7 ) and occur mainly in regions with high rainfall. NAD-ME-type C4 species have significantly lower ¹³C values (–13.4 ) and dominate in the most arid part of the precipitation regime. PCK-type C4 species play an intermediate role (–12.5 ) and reach a maximum abundance in areas of intermediate precipitation. This pattern is also evident in genera containing species of different metabolic types. Within the same genus NAD species reach more negative ¹³C values than PCK species and ¹³C values decreased with rainfall. Also in Aristida, with NADP-ME-type photosynthesis, ¹³C values decreased from –11 in the inland region (600 mm precipitation) to –15 near the coast (150 mm precipitation), which is a change in discrimination which is otherwise associated by a change in metabolism. The exceptional C3 species Eragrostis walteri and Panicum heterostachyum are coastal species experiencing 50 mm precipitation only. Many of the rare species and monotypic genera grow in moist habitats rather than in the desert, and they are not different in their carbon isotope ratios from the more common flora. The role of species diversity with respect to habitat occupation and carbon metabolism is discussed.     

Arctic Small Rodents Have Diverse Diets and Flexible Food Selection

The ecology of small rodent food selection is poorly understood, as mammalian herbivore food selection theory has mainly been developed by studying ungulates. Especially, the effect of food availability on food selection in natural habitats where a range of food items are available is unknown. We studied diets and selectivity of grey-sided voles (Myodes rufocanus) and tundra voles (Microtus oeconomus), key herbivores in European tundra ecosystems, using DNA metabarcoding, a novel method enabling taxonomically detailed diet studies. In order to cover the range of food availabilities present in the wild, we employed a large-scale study design for sampling data on food availability and vole diets. Both vole species had ingested a range of plant species and selected particularly forbs and grasses. Grey-sided voles also selected ericoid shrubs and tundra voles willows. Availability of a food item rarely affected its utilization directly, although seasonal changes of diets and selection suggest that these are positively correlated with availability. Moreover, diets and selectivity were affected by availability of alternative food items. These results show that the focal sub-arctic voles have diverse diets and flexible food preferences and rarely compensate low availability of a food item with increased searching effort. Diet diversity itself is likely to be an important trait and has previously been underrated owing to methodological constraints. We suggest that the roles of alternative food item availability and search time limitations for small rodent feeding ecology should be investigated.

Nomenclature

Annotated Checklist of the Panarctic Flora (PAF), Vascular plants. Available at: http://nhm2.uio.no/paf/, accessed 15.6.2012.     

A unique surface membrane anchored purine-salvage enzyme is conserved among a group of primitive eukaryotic human pathogens

Previously, we isolated and characterized the gene encoding the 3-Nucleotidase/Nuclease (Ld3NT/NU) from the human pathogen, Leishmania donovani. This unique cell surface enzyme has been shown to be involved in the salvage of host-derived purines, which are essential for the survival of this important protozoan parasite. In this report, we assessed whether the 3-Nucleotidase/Nuclease was conserved amongst other pathogenic Leishmania and related trypanosomatid parasites. Results of pulsed field gel electrophoresis and Southern blotting showed that a Ld3NT/NU gene homolog was present in each of the visceral and cutaneous Leishmania species tested (i.e. isolates of L. donovani, L. infantum, L. tropica, L. major and L. mexicana, respectively). Further, results of colorimetric assays using 3-adenosine monophosphate as substrate demonstrated that each of these organisms also expressed significant levels of 3-nucleotidase enzyme activity. In addition, we showed that a Ld3NT/NU gene homolog was expressed in each of these Leishmania species as a > 40 kDa 3-nucleotidase enzyme activity. A Ld3NT/NU gene homolog was also identified in two Crithidia species (C. fasciculata and C. luciliae) and Leptomonas seymouri but was only marginally detectable in Trypanosoma brucei, Trypanosoma cruzi and Phytomonas serpens. Cumulatively, results of this study showed that an Ld3NT/NU homolog was conserved amongst pathogenic Leishmania sp. which suggests that this enzyme must play an critical role in purine salvage for all members of this group of human pathogens.     

Cell wall teichoic acids of actinomycetes of three genera of the order actinomycetales

The structures of cell wall teichoic acids of the members of newly recognized genera of the order Actinomycetales were studied. Planotetraspora mira VKM Ac-2000^T contains two types of teichoic acids: 2,3-poly(glycerol phosphate) substituted with -D-Galp at C-1 of glycerol and 1,3-poly(glycerol phosphate) substituted with -L-Rhap at OH-2 of glycerol (60%). Herbidospora cretacea VKM Ac-1997^T contains the chains of 1,3-poly(glycerol phosphate) partially substituted with -D-Galp and -D-GalpNAc at C-2 of glycerol. The majority of -D-galactopyranosyl residues are substituted at OH-3 with a sulfate. The aforementioned teichoic acids have not been found in bacteria thus far. Actinocorallia herbida VKM Ac-1994^T contains poly(galactosylglycerol phosphate), with the -Galp-(12)-Gro-P repeating units being linked via the phosphodiester bonds between the OH-3 of glycerol and OH-6 of galactose. Earlier, this structure was found in the cell wall of Actinomadura madura. The polymer structures were determined by chemical analysis and using ¹³C-NMR spectroscopy. The results show that teichoic acids are widespread in the order Actinomycetales.     

Fungal endophytes of grasses and their effects on an insect herbivore

Summary The effects of endophytic fungi (Tribe Balansiae, Clavicipitaceae, Ascomycetes) of grasses on an insect herbivore were studied by feeding paired groups of larvae of the fall armyworm (Spodoptera frugiperda, Noctuidae, Lepidoptera) leaves from either infected or uninfected individuals. Perennial ryegrass infected by the Lolium endophyte, tall fescue infected by Epichloe typhina, dallisgrass infected by Myriogenospora atramentosa, Texas wintergrass infected by Atkinsonella hypoxylon, and sandbur infected by Balansia obtecta were utilized. The endophytes of ryegrass and fescue previously have been shown to be toxic to mammalian herbivores and to deter feeding of some insect herbivores. In this study we extend the antiherbivore properties of those endophytes to the fall armyworm and demonstrate that fungal endophytes in three other genera have similar antiherbivore properties. For most grasses, survival and weights of fall armyworm larvae fed infected leaves were significantly lower and larval duration was significantly longer compared to larvae fed uninfected leaves. Resistance to herbivores may provide a selective advantage to endophyte-infected grasses in natural populations.     

Cryphodera kalesari,a new heteroderid nematode species from Haryana,India

Cryphodera kalesari n. sp., recorded on Colebrookea oppositifolia Sm. from the Kalesar forests (Haryana), India, is described. Females: swollen, saccate, with two to three lip annules, with vulval lips protruding. Second stage juveniles: length 384±19 m, spear=26.5±1 m, tail 46.5±6 m, hyaline portion 21.5±2.5 m, en face dorsal and ventral arcs of head skeleton bifurcate. Males: not found.     

A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

A Study of Nucleotide Sequences of nifH Genes of Some Methanotrophic Bacteria

Using a previously developed primer system, nifH gene fragments 450 nucleotides long were amplified, cloned, and sequenced for representatives of nitrogen-fixing methanotrophic bacteria of the genera Methylococcus, Methylocystis, and Methylosinus. Fragments of nifH genes were also detected and sequenced in representatives of the genera Methylomonas and Methylobacter, which were not considered diazotrophs until recently. Phylogenetic analysis revealed the remoteness of nifH gene sequences of methanotroph types I and II. At the same time, a close relationship was found between nifH of type I methanotrophs and representatives of -proteobacteria and between nifH genes of type II methanotrophs and representatives of -proteobacteria. The results obtained in this study are in good accordance with the data of phylogenetic analysis based on 16S rRNA sequence comparison with the only exception being Methylococcus capsulatus strains, whose nifH genes proved to be closely related to nifH genes of Methylocystis and Methylosinus representatives. Our findings extend the database of primary sequences of nifH genes and allow the contribution of methanotrophs to the process of nitrogen fixation to be estimated.     

Cytological characterization,powdery mildew resistance and storage protein composition of tetraploid and hexaploid 1BL/1RS wheat-rye translocation lines

Summary Progenies of a tetraploid 1BL/1RS wheat-rye translocation line, CV 256, selected from the cross Cando x Veery, were analyzed by means of Giemsa C-banding. CV 256 is cytologically stable for the presence of the 1BL/1RS translocation but still segregating for A- and B-genome chromosomes of Cando and Veery. In CV 256, nucleolar activity of the 1RS NOR locus is suppressed, as judged by the absence of a secondary constriction in that rye segment and the capability of organizing nucleoli. PAGE analysis of prolamins confirmed the presence of two 1RS secalins in all single seeds analyzed. SDS-PAGE analysis of reduced glutenins of single seeds indicated that some seeds contained the Cando Glu-B1 locus (subunits 6+8), some contained the Veery Glu-B1 locus (subunits 7+9) while others contained all four subunits, indicating that the material was heterozygous. Pm8 resistance is expressed in the tetraploid 1BL/1RS translocation line based on the reactions of six well-defined powdery mildew isolates. However, Pm8 resistance is not expressed in the hexaploid wheat cultivars Olymp, Heinrich and Florida, which also contain the 1BL/1RS translocation. Obviously, the existence of the 1BL/1RS translocation is not a proof for the expression of the associated genes. PAGE results did not show a clear linkage between powdery mildew resistance and the presence of 1RS secalins.     

Yeasts associated with pollinating bees and flower nectar

A study of the yeast flora of 328 honey stomachs from 7 different pollinating bee species, and 342 flower nectar samples of 9 different flower species yielded 766 yeast isolates composed of 16 genera and 47 species. Most of the yeast species from both the sources belonged to the genusCandida, while the most frequently isolated yeasts wereDekkera intermedia from honey stomach andCandida blankii from flower nectar. Among the honey bees,Xylocopa sp., and among flowers,Citrus medica, yielded the highest number of yeast species. Nineteen species of yeasts belonging to 9 genera were common to both the sources.     

A comparative assessment of TLC overlay technique and microwell adsorption assay in the examination of influenza A and Sendai virus specificities towards oligosaccharides and sialic acid linkages of gangliosides

Influenza A and Sendai viruses bind toneolacto-series gangliosides isolated from human granulocytes. Differences in receptor specificity of influenza viruses A/PR/8/34 (H1N1), A/X-31 (H3N2), and parainfluenza Sendai virus (HNF1, Z-strain) were determined by two direct solid phase binding assays: the overlay technique, which combines high-resolution in the separation of gangliosides on thin-layer chromatograms with direct binding; and the microwell adsorption assay as a convenient binding assay which is performed in microtitre wells to estimate the avidity of binding to an isolated ganglioside. Both methods were applied for comparative binding studies. Viruses were found to exhibit specificity for oligosaccharides and sialic acids as well as for chain length of the neutral carbohydrate backbone, whereas differing fatty acids (C_24:1 and C_16:0) in the ceramide portion had no impact on virus adsorption. Terminal sialyloligosaccharides Neu5Ac2-3Gal1-4Glc-R of G_M3, and Neu5Ac2-3Gal1-4GlcNAc-R as well as Neu5Ac2-6Gal1-4GlcNAc-R ofneolacto-series gangliosides with nLcOse₄Cer and nLcOse₆Cer backbone, exhibited significant specific receptor activity towards the different viruses. To compare the data revealed from both test systems, values of virus binding were ascertained by a non-parametric statistical approach based on rank correlation. The rank correlation coefficientr _s was calculated according to Spearman from each virus binding towards G_M3, IV³Neu5Ac-nLcOse₄Cer, IV⁶Neu5Ac-nLcOse₄Cer and VI³Neu5Ac-nLcOse₆SCer. The rank correlation coefficients 0.74, 0.95 and 0.92, which were determined for A/PR/8/34 (H1N1), A/X-31 (H3N2) and Sendai virus (HNF1, Z-strain), respectively, indicated that both assays generate highly correlated experimental data. Based on these results, analyses of virus binding on thin-layer chromatograms as well as in microwells were found equivalent tools for ganglioside receptor studies. Abbreviations: BSA, bovine serum albumin; GSL(s), glycosphingolipids; HPTLC, high performance thin-layer chromatography; PBS, phosphate buffered saline; Neu5Ac,N-acetylneuraminic acid [35];r _s = rank correlation coefficient according to Spearman. The designation of the glycosphingolipids follows the IUPAC-IUB recommendations [36]. LacCer or lactosylceramide, Gal1-4Glc1-1Cer; lacto-N-neotetraosylceramide or nLcOse₄Cer, Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; lacto-N-norhexaosylceramide or nLcOse₆Cer, Gal1-4GlcNAc1-3Gal1-4GlcNAc1-3Gal1-4Glc1-1Cer; G_M3 (according to Svennerholm [37]) or II³Neu5AcLacCer.     

Neisseria gonorrhoeae IgA protease. Secretion and implications for pathogenesis

A cloned 5 bk DNA fragment from Neisseria gonorrhoeae strain MS11 promotes expression and excretion of IgA protease in E. coli and other Gram-negative hosts. DNA sequencing reveals a large open reading frame coding for a prcursor molecule of 169 kd. The 106 kd mature IgA protease is released from the bacteria in conjunction with a 15 kd soluble precursor segment, the -protein. In contrast, the carboxy terminal portion of the precursor, the -protein (45 kd), remains associated with the outer bacterial membrane. The three proteins result form autoproteolytic cleavage at sites in the precursor which are similar to the target site in IgA1. Consensus sequences of the specific cleavage sites are found in a number of relevant human proteins. IgA protease may therefore have other natural substrates besides IgA1. The soluble -protein as well as the membrane bound -protein, both associated with IgA protease, may confer additional virulence functions to the gonococcus.     

Characterization of the tea fungus metabolites

Summary The tea fungus (commonly designed as kombucha) is a symbiotic culture of at least three microorganisms: the acetic acid bacteria Acetobacter xylinum and two yeasts Zygosaccharomyces rouxii and Candida sp. in sugared tea (Hesseltine, 1965; Anonymous, 1983). These microorganisms were cultured in their traditional medium and several metabolites were identified and quantified : ethanol, lactic, acetic, gluconic and glucuronic acids. The antibacterial product known as usnic acid was also searched.     

Zooplankton community changes in Lake Kinneret (Israel) during 1969–1985

Long-term records (1969–1985) of zooplankton density in Lake Kinneret indicated significant reduction of biomass (Copepods, Cladocera, Rotifera) and production (Copepods, Cladocera). Nauplius and adult copepod densities decreased but those of copepodites did not change. Mesocyclops was suppressed more than the smaller Thermocyclops and males of both genera became more abundant relative to the larger females. Ratios of small/large Cladocera densities became higher. Numbers of total cladocerans were stable, and therefore reduction of Cladocera grazing capacity is assumed. The abundant Keratella spp. were reduced. It is likely that intensification of fish visual-attack-predation pressure shifted the size-class structure towards smaller adult copepods and cladocerans. Reduction of Keratella spp. and copepod nauplii was probably affected by increasing pressure of fish filter-feeders. Data on fish food consumption, feeding behaviour and fisheries management suggested their direct impact on long-term changes of zooplankton in Lake Kinneret.     

Hypoxia Tolerance of Two Haplochromine Cichlids: Swamp Leakage and Potential for Interlacustrine Dispersal

The ability to tolerate hypoxia in some haplochromine cichlid fishes contributes to the richness of habitats occupied by the lineage and may be important in interlacustrine dispersal through swampy channels. Lacustrine members of the genus Astatotilapia tend to be ecologically plastic but are rarely encountered in the interior of dense swamps. A notable exception is seen in the swamp corridor that joins Lake Kabaleka with Lake George, Uganda, where one species (Astatotilapia wrought-iron) is abundant, and a second species, A. aeneocolor, is rare. Both species are abundant in the open waters of the main lake. In this paper, we compare physiological (oxygen consumption) and behavioral indicators of hypoxia tolerance between A. wrought-iron from swamp and open-water habitats and between the two species of Astatotilapia. When exposed to progressive hypoxia, all fish used aquatic surface respiration (ASR); however, swamp-dwelling A. wrought-iron showed lower gill ventilation rates prior to the initiation of ASR, higher pre-ASR aggression rates, higher swimming speed during ASR, and a higher rate of bubble exchange than both the open-water group of A. wrought-iron and A. aeneocolor. These differences may reflect interpopulational variation in selection pressure for low-oxygen tolerance between swamp and open-water habitats. Several lines of evidence suggest that A. wrought-iron was in general more hypoxia tolerant than A. aeneocolor. These include a lower ASR₉₀ threshold, a drop in gill ventilation rate with the onset of ASR, and lower rate of equilibrium loss under extreme hypoxia in A. wrought-iron. The routine metabolic rate and critical oxygen tension did not differ between swamp-dwelling and open-water A. wrought-iron, or between A. wrought-iron and A. aeneocolor. Comparative data on the ASR thresholds and critical oxygen tensions of the Astatotilapia species from Lake Kabaleka and other East African cichlids suggest intermediate hypoxia tolerance. Nevertheless, our study suggests that some generalized lacustrine haplochromines may leak through swamp corridors even under relatively extreme conditions.