Reassessing Neotropical angiosperm distribution patterns based on monographic data: a geometric interpolation approach

Monographic data rely on specimens deposited in herbaria and museums, which have been thoroughly revised by experts. However, monographic data have been rarely used to map species richness at large scale, mainly because of the difficulties caused by spatially heterogeneous sampling effort. In this paper we estimate patterns of species richness and narrow endemism, based on monographic data of 4,055 Neotropical angiosperm species. We propose a geometric interpolation method to derive species ranges at a 1° grid resolution. To this we apply an inverse distance-weighted summation scheme to derive maps of species richness and endemism. In the latter we also adjust for heterogeneous sampling effort. Finally, we test the robustness of the interpolated species ranges and derived species richness by applying the same method but using a leave-one-out-cross-validation (LOOCV). The derived map shows four distinct regions of elevated species richness: (1) Central America, (2) the Northern Andes, (3) Amazonia and (4) the Brazilian Atlantic coast (‘Mata Atlantica’). The region with the highest estimated species richness is Amazonia, with Central America following closely behind. Centers of narrow endemism are located over the entire Neotropics, several of them coinciding with regions of elevated species richness. Sampling effort has a minor influence on the interpolation of overall species richness, but it substantially influences the estimation of regions of narrow endemism. Thus, in order to improve maps of narrow endemism and resulting conservation efforts, more collection and identification activity is required.     

Cytogenetic analysis of mouse metaphase II oocytes following exposure to tritiated water

Female mice were given different dosages (0, 3.0, 7.5, 15.0, or 30 muCi/ml) of tritium in their drinking water continuously from 3 to 7 weeks of age to assess the effects on germ cell chromosomes. At 8-9 weeks of age, mice were superovulated and metaphase II oocytes were processed and C-banded for cytogenetic analyses. Chromatid acentric fragments were the only type of structural aberration detected, and their incidence was higher in controls than in any of the tritiated water (HTO) groups. Analysis of numerical chromosomal aberrations revealed that the incidence of hypoploid (N = 19) oocytes was higher in oocytes from mice who drank HTO as compared with controls. However, the effects of HTO upon aneuploidy induction was not definitive due to the increase the incidence of aberrations in mouse oocytes can be related to the low dose rate resulting from chronic HTO exposure and possibly death of tritium-damaged cells.     

Seasonal variation in food allergy to apple

The aim of the study was to investigate the possibility of a seasonal variation in reactivity to apples in 27 birch pollen allergic patients. Before and during the birch pollen season 1998, the patients were subjected to double-blind, placebo-controlled food challenges (DBPCFCs) with grated fresh Golden Delicious apple followed by an open food challenge with whole fresh apple. The clinical reactions elicited during the challenges were evaluated both by the patients and the investigators. Moreover, the skin reactivity and the in vitro reactivity to apple were evaluated by skin prick test (SPT), leukocyte histamine release (HR), measurement of specific IgE, and immunoblotting experiments. The sensitivity of the DBPCFC, when compared with the result of the open challenge, was 0.74 (14/19) before the season and 0.80 (16/20) during the season. None of the patients reacted to the blinded challenge without a subsequent reaction to the open challenge. One placebo reaction was registered both before and in season, but not in the same patient. The patient scores of the first positive challenges, and the maximal scores of each combined blinded and open challenge session, were significantly increased during the pollen season (P<0.05). The scores of the open challenge were significantly higher than the scores of the DBPCFC both before the season and during the in-season challenges (P<0.05). Specific IgE against Golden Delicious increased during season (P<0.05), while neither SPT, HR, nor immunoblotting experiments could confirm an increase in reactivity. In conclusion, the results of the oral challenge tests indicated an increase in clinical reactivity to apples during the birch pollen season in birch pollen allergic individuals.     

Novel α-L-Fucosidases from a Soil Metagenome for Production of Fucosylated Human Milk Oligosaccharides

This paper describes the discovery of novel α-L-fucosidases and evaluation of their potential to catalyse the transglycosylation reaction leading to production of fucosylated human milk oligosaccharides. Seven novel α-L-fucosidase-encoding genes were identified by functional screening of a soil-derived metagenome library and expressed in E. coli as recombinant 6xHis-tagged proteins. All seven fucosidases belong to glycosyl hydrolase family 29 (GH 29). Six of the seven α-L-fucosidases were substrate-inhibited, moderately thermostable and most hydrolytically active in the pH range 6–7, when tested with para-nitrophenyl-α-L-fucopyranoside (pNP-Fuc) as the substrate. In contrast, one fucosidase (Mfuc6) exhibited a high pH optimum and an unusual sigmoidal kinetics towards pNP-Fuc substrate. When tested for trans-fucosylation activity using pNP-Fuc as donor, most of the enzymes were able to transfer fucose to pNP-Fuc (self-condensation) or to lactose. With the α-L-fucosidase from Thermotoga maritima and the metagenome-derived Mfuc5, different fucosyllactose variants including the principal fucosylated HMO 2’-fucosyllactose were synthesised in yields of up to ~6.4%. Mfuc5 was able to release fucose from xyloglucan and could also use it as a fucosyl-donor for synthesis of fucosyllactose. This is the first study describing the use of glycosyl hydrolases for the synthesis of genuine fucosylated human milk oligosaccharides.     

Linking micromorphism,brooding, and hermaphroditism in brachiopods: Insights from Caribbean Argyrotheca (Brachiopoda)

In extant brachiopods, parental brooding of the larvae occurs exclusively within Rhynchonelliformea. Methods of larval protection range from simple retention of the larvae within the mantle cavity, to sophisticated brood care within highly specialized brood pouches found in Argyrotheca and Joania (Terebratulida, Megathyridoidea), Gwynia (Terebratulida, Gwynioidea), and all Thecideoidea (Thecideida). Previous studies on the reproductive biology of Argyrotheca yielded contrasting results on the epithelial origin of the brood pouches in this genus. Here, representatives of different species of Argyrotheca from the Belize Barrier Reef were examined using histological section series. Brood pouches of four species, A. cf. schrammi and Argyrotheca sp. 1–3, are of the same basic structure, formed by invaginations of the anterior body wall and connected to the visceral cavity via the metanephridia. The same four species are simultaneously hermaphroditic, suggesting that fertilization is achieved, at least partly, through selfing. One species, Argyrotheca rubrocostata, differs significantly from all others as it has no brood pouch and gonochoric gonads. Thus, the presence of brood pouches and simultaneous hermaphroditism are concluded to be correlated within Megathyridoidea and proposed to be homologous traits of Joania and several but not all species of Argyrotheca, questioning the monophyletic status of both genera. In contrast to the brood pouches of Thecideoidea, lophophoral epithelium is not involved in the formation of the pouches of Argyrotheca and Joania. Therefore, megathyridoid and thecideoid brood pouches are not homologous but evolved independently within rhynchonelliform brachiopods. All brachiopods with brood pouches share a micromorphic form and a short life span, limiting the space and time available for gamete and larval development. We suggest that the brood pouches and the hermaphroditic gonads of Argyrotheca spp. and Joania compensate these limitations by minimizing the loss of gametes and larvae, and by maximizing the chances of successful fertilization. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc.     

MPTP, MPP+ and mitochondrial function

1-Methyl-4-phenylpyridinium (MPP+), the putative toxic metabolite of the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), inhibited NAD(H)-linked mitochondrial oxidation at the level of Complex I of the electron transport system. MPTP and MPP+ inhibited aerobic glycolysis in mouse striatal slices, as measured by increased lactate production; MPTP-induced effects were prevented by inhibition of monoamine oxidase B activity. Several neurotoxic analogs of MPTP also form pyridinium metabolites via MAO; these MPP+ analogs were all inhibitors of NAD(H)-linked oxidation by isolated mitochondria. 2'-Methyl-MPTP, a more potent neurotoxin in mice than MPTP, was also more potent than MPTP in inducing lactate accumulation in mouse brain striatal slices. Overall, the studies support the hypothesis that compromise of mitochondrial oxidative capacity is an important factor in the mechanisms underlying the toxicity of MPTP and similar compounds.     

The structure of toxic protein, the mistletoe lectin, at different pH: the study using intrinsic fluorescence method

The effects of pH on the conformation of mistletoe lectin I and its isolated A- and B-subunits has been investigated by using the methods of intrinsic fluorescence. By the denaturating action of guanidine hydrochloride and the influence of the quenchers (I-, Cs+, acrylamide) the structural stability of the native protein and its isolated subunits was estimated. Treatment of the protein with the denaturant and quenchers revealed its different structure at pH 7.0 and 4.0. At pH 4.0 tryptophan residues become more accessible to quenchers, positive charge of the surrounding area increases and the protein becomes more stable to the action of denaturant. The structure of the isolated A- and B-chains of mistletoe lectin I differs considerably from that of the whole protein: a) its stability to the action of guanidine hydrochloride is lower; b) it depends on the ionic strength of the solvent; c) it is characterized by increased accessibility of tryptophan residues to quenchers (for B-chain). Differences between the conformations of the isolated chains at pH 7.0 and 4.0 are marked more strongly; moreover, at pH 4.5 the B-chain undergoes structural transition. The possible relationship between structural peculiarities of mistletoe lectin I and the mechanism of its transmembrane transfer is discussed.     

Allergy against chironomids (non biting midges) in adult atopic patients

Summary The aim of this investigation was to evaluate the prevalence of atopic sensitization to chironomids (CHI) in patients with asthma and/or rhinitis (A/R), and to study concomitant sensitization to CHI and other allergens. Skin prick tests were performed with 3 different CHI extracts as well as with common inhalant allergens in 600 consecutive patients, 495 of which had A/R. Allergen specific IgE antibodies in the sera against CHI, shell fish and cockroaches were analyzed with Magic Lite.59 (12%) of the patients with A/R had a positive skin test with CHI. Positive skin tests with house dust mites and a storage mite were more common in CHI allergic patients than in other atopic patients. Nasal or conjunctival provocation tests, performed on 23 of the patients with positive skin test with CHI, were clearly positive in 7 cases (30%), questionable in 8 (35%) and negative in 8 cases (35%).Magic Lite, performed on sera from 50 of the patients with positive skin test against CHI, was positive with CHI in 39 cases (78%), with crayfish in 33 (66%), shrimp 20 (40%), cockroach 21 (40%) and with crab in 3 cases (6%).It is concluded that sensitization against CHI is common in patients with A/R. The clinical relevance of the positive test results is, however, unknown. Concomitant sensitization with CHI, crustaceans and cockroach is common.     

A variable region gene subfamily encoding T cell receptor beta-chains is selectively conserved among mammals

Studies of murine T cell receptor genes indicate that the VT beta repertoire, in contrast to the large VT alpha, VH, and VK repertoires, is limited to approximately 21 genes. Large differences between the various VT beta sequences allow classification into distinct subfamilies consisting of one or few members. The VT beta sequence of a gene, RTB92, expressed in a rabbit T cell line is most closely related to a VT beta gene expressed in the human cell line Molt-4. Genomic blots with RTB92 VT beta region used as probe indicated conservation of related VT beta gene subfamilies in man and pig, but no related sequences were seen in rat, mouse, or hamster. The relationship among these VT beta genes mirrors similarities and differences in MHC genes of the compared species and suggests coordinate evolution of these functionally related gene families. The constant region of RTB92 was shown to be rabbit CT beta 2 by reference to genomic clones. Comparisons with constant region sequences of human and murine CT beta 1 and CT beta 2 chains reveal no similarities in amino acid or nucleic acid sequence in the coding region characteristic of the respective isotypes. Intraspecies homologies between CT beta 1 and CT beta 2 sequences were much greater than those between CT beta 1 or CT beta 2 from other species. By contrast, comparisons of JT beta and 3' untranslated region sequences showed significant interspecies conservation of sequences in the beta 1 and in the beta 2 regions.