New records of the rare North American endemic <Emphasis Type="Italic">Chara brittonii</Emphasis> (Characeae), with comments on its distribution

Characeae is a family of freshwater green algal macrophytes found on every continent except Antarctica. Although some species are thought to be cosmopolitan, others appear to be restricted to relatively small geographic areas. Chara brittonii is a North American endemic previously reported from eight scattered populations in Indiana, Michigan, New Jersey, and Ohio. Given that few extant populations were known, basic questions about its distribution, habitat preference, morphology, and phylogenetic placement remained unanswered. We have surveyed every reported locality for C. brittonii except the New Jersey locality, because the collection details are vague, and also surveyed numerous additional waterbodies in Indiana, Michigan, and Wisconsin. We have found extant populations in nine localities in three states. These include one newly reported site in Indiana and five newly reported sites in Wisconsin, the first known populations in that state. Chara brittonii seems to have been extirpated from several historical sites in recent decades. We expanded both the range and the number of known extant populations for C. brittonii and hypothesize that C. brittonii may be more widespread in the Midwest than previously thought. Factors contributing to the actual and apparent rarity of this species are discussed including its preferred habitat and small size. We observed that the number of antheridial scute cells of C. brittonii varied from 4–8 with both triangular and elongate scutes produced on the same thallus, an unusual condition for the family. Phylogenetic analyses using three plastid-encoded markers placed C. brittonii among a paraphyletic grade of C. foliolosa sensu lato strains in the monophyletic subsection Willdenowia. We propose that C. foliolosa, as currently recognized, represents a species complex of several phylogenetically distinct lineages, and conclude that C. brittonii is a structurally and phylogenetically distinct species worthy of conservation.     

Cophylogenetic assessment of New World warblers (Parulidae) and their symbiotic feather mites (Proctophyllodidae)

Host–symbiont relationships are ubiquitous in nature, yet evolutionary and ecological processes that shape these intricate associations are often poorly understood. All orders of birds engage in symbioses with feather mites, which are ectosymbiotic arthropods that spend their entire life on hosts. Due to their permanent obligatory association with hosts, limited dispersal and primarily vertical transmission, we hypothesized that the cospeciation between feather mites and hosts within one avian family (Parulidae) would be perfect (strict cospeciation). We assessed cophylogenetic patterns and tested for congruence between species in two confamiliar feather mite genera (Proctophyllodidae: Proctophyllodes, Amerodectes) found on 13 species of migratory warblers (and one other closely related migratory species) in the eastern United States. Based on COI sequence data, we found three Proctophyllodes lineages and six Amerodectes lineages. Distance‐ and event‐based cophylogenetic analyses suggested different cophylogenetic trajectories of the two mite genera, and although some associations were significant, there was little overall evidence supporting strict cospeciation. Host switching is likely responsible for incongruent phylogenies. In one case, we documented prairie warblers Setophaga discolor harboring two mite species of the same genus. Most interestingly, we found strong evidence that host ecology may influence the likelihood of host switching occurring. For example, we documented relatively distantly related ground‐nesting hosts (ovenbird Seiurus aurocapilla and Kentucky warbler Geothlypis formosa) sharing a single mite species, while other birds are shrub/canopy or cavity nesters. Overall, our results suggest that cospeciation is not the case for feather mites and parulid hosts at this fine phylogenetic scale, and raise the question if cospeciation applies for other symbiotic systems involving hosts that have complex life histories. We also provide preliminary evidence that incorporating host ecological traits into cophylogenetic analyses may be useful for understanding how symbiotic systems have evolved.     

Microbial and plant-derived compounds both contribute to persistent soil organic carbon in temperate soils

Our study tests the emerging paradigm that biochemical recalcitrance does not affect substantially long-term (50 years) SOC persistence. We analyzed the molecular composition of SOC in archived soils originating from four European long-term bare fallow experiments (Askov, Rothamsted, Versailles and Ultuna). The soils had been collected after various periods (up to 53 years) under bare fallow. With increasing duration of bare fallow without new organic inputs, the relative abundance of cutin- and suberin-derived compounds declined substantially, and the abundance of lignin-derived compounds was close to zero. Conversely, the relative abundance of plant-derived long-chain alkanes remained almost constant or increased during the bare fallow period. The relative abundance of N-containing compounds, considered to be abundant in SOC derived from microbial activity, increased consistently illustrating that microbial turnover of SOC continues even when plant inputs are stopped. The persistence of the different families of plant-derived compounds differed markedly over the scale of half a century, which may be ascribed to their contrasting chemical characteristics and recalcitrance, or to differences in their interactions with the soil mineral matrix, and likely some combination since chemical composition drives the degree of mineral association. Using soil from this unique set of long-term bare fallow experiments, we provide direct evidence that multi-decadal scale persistent SOC is enriched in microbe-derived compounds but also includes a substantial fraction of plant-derived compounds.     

Alcohol withdrawal-induced changes in brain biogenic amines in mice: Influence of the genotype

Alterations in striatal and hippocampal dopamine (DA) and serotonin (5HT) activities were investigated in two inbred strains of mice (C57B1 and Balb/c) after 3 withdrawal periods following 5 months chronic ethanol administration. Two groups of animals with different levels of ethanol administration (15% and 30%, v/v) were examined. A striking strain dependency has been noted. Striatal dopaminergic mechanisms of the Balb/c strain are profoundly disturbed in both groups. In contrast no changes were noted for either transmitter activities in C57B1 mice at any withdrawal time studied. Strain dependency has also been noted for hippocampal serotonin neurotransmission, since only Balb/c mice showed a progressive decrease in 5HT levels. These impairments observed in striatum and hippocampus could be involved in motor incoordinations and convulsions often associated with the withdrawal syndrome. The differences in withdrawal effects we noted between the two strains may be linked to the specific chemical neuroanatomy of the strains. Such specificities could be implied in the well known variability of withdrawal induced behavior in man.     

Demonstration of an interferon alpha receptor in human colonic cancer cells in culture

The IFN-alpha 2 receptor present in human cancerous colonic cells in culture has a capacity of 1,800 sites per cell with a kd of 0.5 nM. The molecular mass of the interferon alpha 2 (IFN-alpha 2) receptor complex is 134 kd. The IFN-alpha 2 induces the activity of the 2'5' oligoadenylate (2'5' A) synthetase activity in these cells and partly inhibits their growth.     

Transforming Global Health by Improving the Science of Scale-Up

In its report Global Health 2035, the Commission on Investing in Health proposed that health investments can reduce mortality in nearly all low- and middle-income countries to very low levels, thereby averting 10 million deaths per year from 2035 onward. Many of these gains could be achieved through scale-up of existing technologies and health services. A key instrument to close this gap is policy and implementation research (PIR) that aims to produce generalizable evidence on what works to implement successful interventions at scale. Rigorously designed PIR promotes global learning and local accountability. Much greater national and global investments in PIR capacity will be required to enable the scaling of effective approaches and to prevent the recycling of failed ideas. Sample questions for the PIR research agenda include how to close the gap in the delivery of essential services to the poor, which population interventions for non-communicable diseases are most applicable in different contexts, and how to engage non-state actors in equitable provision of health services in the context of universal health coverage.     

Early evolution of the chromosomal structure of Triticum turgidum–Aegilops ovata amphiploids carrying and lacking the Ph1 gene

After two selfing generations of two different Triticum turgidum –Aegilops ovata amphiploids carrying the Ph1 gene, or lacking it (ph1c mutant), karyotypes of their offspring were scored by GISH (genomic in situ hybridization). On average, the chromosome number was lower than expected (56 chromosomes) on the basis of the parental constitutions (T. turgidum, AABB, 2n=4x=28; Ae. ovata, M^oM^oU^oU^o, 2n=4x=28). The lost chromosomes belonged to the wild Aegilops species. The two families differed greatly by their number of intergenomic translocations, also detected by GISH. The ph1c family showed nine translocations over 12 plants while only one translocation was observed in the Ph1 family. All exchanges involved either the M^o and U^o chromosomes or the M^o and wheat chromosomes, the size of the exchanged segment ranging from 3% to 36% of the total chromosome length. The results suggest an epistatic effect of the ph1c deletion over the genetic diploidizing system that operates in Ae. ovata since translocated chromosomes are most-likely derived from homoeologous recombination. The potential of these results for wheat breeding programmes is also considered. Received: 28 November 2000 / Accepted: 20 March 2001     

Bacteriophage PhiX174's Ecological Niche and the Flexibility of Its Escherichia coli Lipopolysaccharide Receptor

To determine bacteriophage PhiX174''s ecological niche, 783 Escherichia coli isolates were screened for susceptibility. Sensitive strains are diverse regarding their phylogenies and core lipopolysaccharides (LPS), but all have rough phenotypes. Further analysis of E. coli K-12 LPS mutants revealed that PhiX174 can use a wide diversity of LPS structures to initiate its infectious process.PhiX174 belongs to the Microviridae family of bacteriophages (12). It is a small, icosahedral, nontailed virus with a circular single-stranded DNA. From its isolation in 1935 up to now, PhiX174 has been used in many landmark experiments because of its small genome size (5,386 nucleotides [nt]) and nonpathogenic status. Furthermore, since PhiX174 is a coliphage, it can be used as an indicator of viral or fecal contamination in aquatic environments (International Organization for Standardization, ISO 10705-2) (5).In 1974, Suzuki et al. found that while phage adsorption is restricted to bacteria which possess a specific receptor, the replication of PhiX174 DNA can be supported by different Escherichia coli strains and distantly related bacteria, such as Pseudomonas aeruginosa (28). These findings imply that the limiting step for PhiX174 infection is entry and not replication or lysis. The commonly used PhiX174 host is the laboratory-derived strain E. coli C, which has a specific rough lipopolysaccharide (LPS) recognized as the receptor (13).The LPS is a major component of the outer membrane of Gram-negative enterobacteria, which is involved in interactions with both biotic and abiotic factors in the environment. It is composed of a lipid A anchored in the membrane and an oligosaccharide core and can have a polysaccharide (O antigen) bound to this core. The inner part of the core LPS is highly conserved within the Gram-negative bacteria (1), whereas the outer-core biochemical structure of the LPS is more diverse. In the E. coli species, five outer-core types have been described: R1, R2, R3, R4, and K-12 (1). E. coli C exhibits an R1 core type. The study of its recently published sequence reveals that its core LPS is fully functional but that the O antigen is affected by an IS insertion in the rfb locus that generates its rough phenotype (GenBank accession number {"type":"entrez-nucleotide","attrs":{"text":"CP000946","term_id":"169752989","term_text":"CP000946"}}CP000946). Interestingly, a similar IS insertion is found in K-12 (4), creating a rough phenotype, but the bacterium is still resistant to PhiX174, which suggests that the exposed R1 core might be critical for PhiX174 infection. Among the E. coli Reference Collection (ECOR), which is representative of the genetic diversity of the entire E. coli species (1, 20), up to 70% of isolates are of the R1 type (1). However, only 3% (8/291) of E. coli strains isolated from sewage, stools, drinking water, or the laboratory have been found to be sensitive to PhiX174 (19).To better define the molecular determinants affecting the ecological niche of the model virus PhiX174, we did the following: (i) screened a large collection of natural E. coli isolates for PhiX174 susceptibility, (ii) characterized the identified sensitive strains based on their phylogenetic group, serotype, and LPS core type, and (iii) studied the susceptibility to PhiX174 of LPS mutants of E. coli K-12. Our analysis revealed that PhiX174 sensitivity is a phenotypic convergence with diverse molecular origins.     

The CRH family coding for cell wall glycosylphosphatidylinositol proteins with a predicted transglycosidase domain affects cell wall organization and virulence of Candida albicans

In Candida albicans UTR2 (CSF4), CRH11, and CRH12 are members of a gene family (the CRH family) that encode glycosylphosphatidylinositol-dependent cell wall proteins with putative transglycosidase activity. Deletion of genes of this family resulted in additive sensitivity to compounds interfering with normal cell wall formation (Congo red, calcofluor white, SDS, and high Ca(2+) concentrations), suggesting that these genes contribute to cell wall organization. A triple mutant lacking UTR2, CRH11, and CRH12 produced a defective cell wall, as inferred from increased sensitivity to cell wall-degrading enzymes, decreased ability of protoplasts to regenerate a new wall, constitutive activation of Mkc1p, the mitogen-activated protein kinase of the cell wall integrity pathway, and an increased chitin content of the cell wall. Importantly, this was accompanied by a decrease in alkali-insoluble 1,3-beta-glucan but not total glucan content, suggesting that formation of the linkage between 1,3-beta-glucan and chitin might be affected. In support of this idea, localization of a Utr2p-GFP fusion protein largely coincided with areas of chitin incorporation in C. albicans.As UTR2 and CRH11 expression is regulated by calcineurin, a serine/threonine protein phosphatase involved in tolerance to antifungal drugs, cell wall morphogenesis, and virulence, this points to a possible relationship between calcineurin and the CRH family. Deletion of UTR2, CRH11, and CRH12 resulted in only a partial overlap with calcineurin-dependent phenotypes, suggesting that calcineurin has additional targets. Interestingly, cells deleted for UTR2, CRH11, and CRH12 were, like a calcineurin mutant, avirulent in a mouse model of systemic infection but retained the capacity to colonize target organs (kidneys) as the wild type. In conclusion, this work establishes the role of UTR2, CRH11, and CRH12 in cell wall organization and integrity.     

Kant on epigenesis, monogenesis and human nature: the biological premises of anthropology

The aim of this paper is to show that for Kant, a combination of epigenesis and monogenesis is the condition of possibility of anthropology as he conceives of it and that moreover, this has crucial implications for the biological dimension of his account of human nature. More precisely, I begin by arguing that Kant's conception of mankind as a natural species is based on two premises: firstly the biological unity of the human species (monogenesis of the human races); and secondly the existence of 'seeds' which may or may not develop depending on the environment (epigenesis of human natural predispositions). I then turn to Kant's account of man's natural predispositions and show that far from being limited to the issue of races, it encompasses unexpected human features such as gender, temperaments and nations. These predispositions, I argue, are means to the realisation of Nature's overall purpose for the human species. This allows me to conclude that man's biological determinism leads to the species' preservation, cultivation and civilisation.