Fucus distichus L. and related species in the British Isles in relation to sea temperature change

Seawater temperature rise may have adverse effects on Fucus species in the British Isles with changes in distribution, abundance or loss of northern species. The use of the F. distichus complex as an indicator of sea temperature rise is investigated. Plants were cultured at 5, 10 and 15ºC to investigate the temperature tolerances in both juvenile and adult life stages of various Fucus species and taxa from different geographic locations. Head, rhizoid and total length of germlings were measured. Surface area, wet (fresh) weight, photosynthesis and respiration measurements were taken for apical tips of adult plants. Extra growth, regeneration and formation of receptacles was noted. Phenotypic variations between populations of the subspecies anceps from Scotland and Ireland were examined. Germlings of Orkney species F. distichus subsp. anceps, F. serratus, F. spiralis and F. vesiculosus grew best at 15ºC; F. vesiculosus var. linearis initially best at 15ºC, changing thereafter to 10ºC; F. spiralis f. nanus grew best at 5ºC. F. distichus subsp. anceps from Ireland grew best at 10ºC. In Orkney adult plants optimum temperature for growth was 15ºC for anceps and serratus, 10ºC and 15ºC for spiralis, vesiculosus, nanus and linearis. In Ireland populations, adult plants of anceps and linearis showed a similar response to temperature with no optimum temperature preference for growth. F. distichus subsp. edentatus from Moray Firth grew best at 5ºC. No temperature preference was noted for edentatus from Shetland. In serratus, spiralis and vesiculosus from South Queensferry, Firth of Forth, only spiralis showed a temperature preference, at 10ºC. Formation of receptacles, new growth and regeneration was present on apical tips of Orkney anceps cultivated at 5ºC. Reproductive tips were noted at temperatures of 5, 10, 15ºC in Ireland anceps. Key findings were: The effects of different temperatures on growth rates of head, rhizoid or both and total length varied between Fucus species and within species. Ecophysiological preferences may be different between the geographically different populations of anceps and linearis from Orkney and Ireland. Populations of anceps from Scotland and Ireland showed no evidence of two discrete phenotypic entities. However differences were seen with respect to size and form and aspects of reproduction with smaller oogonia in anceps from Ireland. The use of the subsp. anceps from Ireland as an indicator of climate change and sea temperature rise in the British Isles seems appropriate. In Britain, increased sea temperatures may not directly determine the distribution of the subsp. edentatus, distribution possibly determined by nutrient enrichment in seawater and/or daylength. There is little evidence to suggest that sea temperature rise and climate change will have any immediate effect on the distribution of the other Fucus species investigated

Renal connective tissue growth factor induction in experimental diabetes is prevented by aminoguanidine

The aim of this study was to determine whether aminoguanidine (AG), an inhibitor of advanced glycation, prevents expression of the profibrotic cytokine, connective tissue growth factor (CTGF), as well as accumulation of the previously reported CTGF-dependent matrix protein, fibronectin, in a model of experimental diabetic nephropathy. Diabetic animals were randomly allocated into groups receiving 32 wk of AG or vehicle. Diabetic rats showed increases in CTGF mRNA and protein expression as well as in advanced glycation end-product (AGE) and fibronectin immunostaining, compared with nondiabetic rats. In the diabetic kidney, the increase in CTGF gene and protein expression as well as expression of the extracellular matrix protein fibronectin were prevented by AG. To further explore the relationship between AGEs and mesangial CTGF and fibronectin production, cultured human mesangial cells were exposed in vitro to soluble AGE-BSA and carboxymethyl lysine-BSA, and this led to induction of both CTGF and fibronectin. On the basis of our in vitro findings in mesangial cells linking AGEs to CTGF expression, the known prosclerotic effects of CTGF, and the ability of AG to attenuate mesangial expansion, it is postulated that the antifibrotic effects of AG in this animal model may be partially mediated by CTGF

Widespread colonization of the lung by Tropheryma whipplei in HIV infection.

RationaleLung infections caused by opportunistic or virulent pathogens are a principal cause of morbidity and mortality in HIV infection. It is unknown whether HIV infection leads to changes in basal lung microflora, which may contribute to chronic pulmonary complications that increasingly are being recognized in individuals infected with HIV.ObjectivesTo determine whether the immunodeficiency associated with HIV infection resulted in alteration of the lung microbiota.MethodsWe used 16S ribosomal RNA targeted pyrosequencing and shotgun metagenomic sequencing to analyze bacterial gene sequences in bronchoalveolar lavage (BAL) and mouths of 82 HIV-positive and 77 HIV-negative subjects.Measurements and main resultsSequences representing Tropheryma whipplei, the etiologic agent of Whipple's disease, were significantly more frequent in BAL of HIV-positive compared with HIV-negative individuals. T. whipplei dominated the community (>50% of sequence reads) in 11 HIV-positive subjects, but only 1 HIV-negative individual (13.4 versus 1.3%; P = 0.0018). In 30 HIV-positive individuals sampled longitudinally, antiretroviral therapy resulted in a significantly reduced relative abundance of T. whipplei in the lung. Shotgun metagenomic sequencing was performed on eight BAL samples dominated by T. whipplei 16S ribosomal RNA. Whole genome assembly of pooled reads showed that uncultured lung-derived T. whipplei had similar gene content to two isolates obtained from subjects with Whipple's disease.ConclusionsAsymptomatic subjects with HIV infection have unexpected colonization of the lung by T. whipplei, which is reduced by effective antiretroviral therapy and merits further study for a potential pathogenic role in chronic pulmonary complications of HIV infection

Widespread colonization of the lung by Tropheryma whipplei in HIV infection.

RationaleLung infections caused by opportunistic or virulent pathogens are a principal cause of morbidity and mortality in HIV infection. It is unknown whether HIV infection leads to changes in basal lung microflora, which may contribute to chronic pulmonary complications that increasingly are being recognized in individuals infected with HIV.ObjectivesTo determine whether the immunodeficiency associated with HIV infection resulted in alteration of the lung microbiota.MethodsWe used 16S ribosomal RNA targeted pyrosequencing and shotgun metagenomic sequencing to analyze bacterial gene sequences in bronchoalveolar lavage (BAL) and mouths of 82 HIV-positive and 77 HIV-negative subjects.Measurements and main resultsSequences representing Tropheryma whipplei, the etiologic agent of Whipple's disease, were significantly more frequent in BAL of HIV-positive compared with HIV-negative individuals. T. whipplei dominated the community (>50% of sequence reads) in 11 HIV-positive subjects, but only 1 HIV-negative individual (13.4 versus 1.3%; P = 0.0018). In 30 HIV-positive individuals sampled longitudinally, antiretroviral therapy resulted in a significantly reduced relative abundance of T. whipplei in the lung. Shotgun metagenomic sequencing was performed on eight BAL samples dominated by T. whipplei 16S ribosomal RNA. Whole genome assembly of pooled reads showed that uncultured lung-derived T. whipplei had similar gene content to two isolates obtained from subjects with Whipple's disease.ConclusionsAsymptomatic subjects with HIV infection have unexpected colonization of the lung by T. whipplei, which is reduced by effective antiretroviral therapy and merits further study for a potential pathogenic role in chronic pulmonary complications of HIV infection