Diversity of Rhizobia Nodulating Phaseolus vulgaris L. in Two Kenyan Soils with Contrasting pHs

Rhizobia were isolated from two Kenyan soils with pHs of 4.5 and 6.8 and characterized on the basis of their host ranges for nodulation and nitrogen fixation, colony morphologies, restriction fragment fingerprints, and hybridization with a nifH probe. The populations of rhizobia nodulating Phaseolus vulgaris in the two soils were similar in numbers and in effectiveness of N(inf2) fixation but were markedly different in composition. The population in the Naivasha soil (pH 6.8) was dominated by isolates specific in host range for nodulation to P. vulgaris; these all had multiple copies, in most cases four, of the structural nitrogenase gene nifH. Only one of the isolates from this soil formed effective nodules on Leucaena leucocephala, and this isolate had only a single copy of nifH. By contrast, the population in the acid Daka-ini soil (pH 4.5) was composed largely of broad-host-range isolates which had single copies of nifH. The isolates from the Daka-ini soil which were specific to P. vulgaris generally had three copies of nifH, although one isolate had only two copies. These rhizobial isolates are indigenous to Kenyan soils and yet have marked similarities to previously described Rhizobium species from other continents.     

Individualized Exercise Training at Maximal Fat Oxidation Combined with Fruit and Vegetable-Rich Diet in Overweight or Obese Women: The LIPOXmax-Réunion Randomized Controlled Trial

Objectives

Lifestyle combined interventions are a key strategy for preventing type-2 diabetes (T2DM) in overweight or obese subjects. In this framework, LIPOXmax individualized training, based on maximal fat oxidation [MFO], may be a promising intervention to promote fat mass (FM) reduction and prevent T2DM. Our primary objective was to compare three training programs of physical activity combined with a fruit- and vegetable-rich diet in reducing FM in overweight or obese women.

Design and setting

A five months non-blinded randomized controlled trial (RCT) with three parallel groups in La Réunion Island, a region where metabolic diseases are highly prevalent.

Subjects

One hundred and thirty-six non-diabetic obese (body mass index [BMI]: 27–40 kg/m²) young women (aged 20–40) were randomized (G1: MFO intensity; G2: 60% of VO₂-peak intensity; G3: free moderate-intensity at-home exercise following good physical practices).

Outcomes

Anthropometry (BMI, bodyweight, FM, fat-free mass), glucose (fasting plasma glucose, insulin, HOMA-IR) and lipid (cholesterol and triglycerides) profiles, and MFO values were measured at month-0, month-3 and month-5.

Results

At month-5, among 109 women assessed on body composition, the three groups exhibited a significant FM reduction over time (G1: -4.1±0.54 kg; G2: -4.7±0.53 kg; G3: -3.5±0.78 kg, p<0.001, respectively) without inter-group differences (p = 0.135). All groups exhibited significant reductions in insulin levels or HOMA-IR index, and higher MFO values over time (p<0.001, respectively) but glucose control improvement was higher in G1 than in G3 while MFO values were higher in G1 than in G2 and G3. Changes in other outcome measures and inter-group differences were not significant.

Conclusion

In our RCT the LIPOXmax intervention did not show a superiority in reducing FM in overweight or obese women but is associated with higher MFO and better glucose control improvements. Other studies are required before proposing LIPOXmax training for the prevention of T2DM in overweight or obese women.

Trial Registration

ClincialTrials.gov NCT01464073     

Simulation of potential range expansion of oak disease caused by Phytophthora cinnamomi under climate change

This study examines the effects of climate warming on one of the most widely distributed and destructive forest pathogens, Phytophthora cinnamomi. In Europe, the winter survival of the pathogen is the dominant cue for the development of the disease it causes to oaks, especially Quercus robur and Q. rubra. The potential pathogen and disease geographic ranges were compared in France between two reference periods, 1968–1998 and 2070–2099. Simulations were obtained by combining a physiologically based approach predicting the pathogen winter survival in relation to microhabitat temperature (in the phloem of infected trees) with a regionalized climatic scenario derived from a global circulation model. Positive anomalies in winter temperatures calculated with this scenario were in the range 0.5–5°C between the periods 2070–2099 and the 1968–1998, according to sites and months. As a consequence, higher annual rates of P. cinnamomi survival were predicted, resulting in a potential range expansion of the disease of one to a few hundred kilometers eastward from the Atlantic coast within one century. Based on this example, the study emphasizes the need of a better understanding of the impacts of global change on the biotic constraint constituted by plant pathogens.     

Solid phase synthesis and antiprotozoal evaluation of di- and trisubstituted 5'-carboxamidoadenosine analogues

The rapid increase of resistance to drugs commonly used in the treatment of tropical diseases such as malaria and African sleeping sickness calls for the prompt development of new safe and efficacious drugs. The pathogenic protozoan parasites lack the capability of synthesising purines de novo and they take up preformed purines from their host through various transmembrane transporters. Adenosine derivatives constitute a class of potential therapeutics due to their selective internalisation by these transporters. Automated solid-phase synthesis can speed up the process of lead finding and we pursued the solid-phase synthesis of di- and trisubstituted 5'-carboxamidoadenosine derivatives by using a safety-catch approach. While efforts with Kenner's sulfonamide linker remained fruitless, successful application of the hydrazide safety-catch linker allowed the construction of two representative combinatorial libraries. Their antiprotozoal evaluation identified two compounds with promising activity: N(6)-benzyl-5'-N-phenylcarboxamidoadenosine with an IC(50) value of 0.91 microM against Trypanosoma brucei rhodesiense and N(6)-diphenylethyl-5'-phenylcarboxamidoadenosine with an IC(50) value of 1.8 microM against chloroquine resistant Plasmodium falciparum.     

NMR-detected order in core residues of denatured bovine pancreatic trypsin inhibitor

The NMR characteristics of [14-38]Abu, a synthetic variant of BPTI that is partially folded in aqueous buffer near neutral pH, support a model of early folding events which begin with stabilization of the nativelike, slow exchange core [Barbar, E., Hare, M., Daragan, V., Barany, G., and Woodward, C. (1998) Biochemistry 37, 7822-7833 (1)]. In partially folded [14-38]Abu, urea denaturation profiles for representative amide protons show that global unfolding is non-two-state and that core residues require a higher concentration of urea to unfold. Dynamic properties of pH-denatured [14-38]Abu and fully reduced and unfolded BPTI analogue were determined from heteronuclear NMR relaxation measurements at similar solution conditions. Differences at various sites in the polypeptide chain were evaluated from spectral density functions determined from T1, T2, and steady-state heteronuclear NOE data. Although denatured [14-38]Abu contains no persistent secondary structure, its most ordered residues are those that, in native BPTI, fold into the slow exchange core. The fully reduced analogue is significantly more mobile and shows less heterogeneous dynamics, but at 1 degree C, restricted motion is observed for residues in the central segments of the polypeptide chain. These observations indicate that there is a developing core or cores even in highly unfolded species. Apparently the effect of 14-38 disulfide on unfolded     

Estrogen receptor alpha, but not beta, is required for optimal dendritic cell differentiation and [corrected] CD40-induced cytokine production

Dendritic cells (DC) are critical actors in the initiation of primary immune responses and regulation of self-tolerance. The steroid sex hormone 17beta-estradiol (E(2)) has been shown to promote the differentiation of DCs from bone marrow (BM) precursors in vitro. However, the estrogen receptor (ER) involved in this effect has not yet been characterized. Using recently generated ERalpha- or ERbeta-deficient mice, we investigated the role of ER isotypes in DC differentiation and acquisition of effector functions. We report that estrogen-dependent activation of ERalpha, but not ERbeta, is required for normal DC development from BM precursors cultured with GM-CSF. We show that reduced numbers of DCs were generated in the absence of ERalpha activation and provide evidence for a cell-autonomous function of ERalpha signaling in DC differentiation. ERalpha-deficient DCs were phenotypically and functionally distinct from wild-type DCs generated in the presence of estrogens. In response to microbial components, ERalpha-deficient DCs failed to up-regulate MHC class II and CD86 molecules, which could account for their reduced capacity to prime naive CD4(+) T lymphocytes. Although they retained the ability to express CD40 and to produce proinflammatory cytokines (e.g., IL-12, IL-6) upon TLR engagement, ERalpha-deficient DCs were defective in their ability to secrete such cytokines in response to CD40-CD40L interactions. Taken together, these results provide the first genetic evidence that ERalpha is the main receptor regulating estrogen-dependent DC differentiation in vitro and acquisition of their effector functions.     

Fine mapping of a major locus on Chromosome 10 for exploratory and fear-like behavior in mice

Advanced intercross lines (AIL) and interval–specific congenic strains (ISCS) were used to fine map previously coarsely defined quantitative trait loci (QTL) on Chromosomes 1,10, and 19, influencing behaviors in the open Field (OF) and light–dark (LD) paradigms in mice. F₁₂(A × B) AIL mice (N = 1130) were phenotyped, genotyped, and mapped. The ISCS were studied only in the telomeric Chromosome 10 region of interest, containing the exploratory and excitability QTL1 (Exq1). The Chromosome 10 Exq1 and Chromosome 19 Exq4 loci mapped robustly in the AIL. The most significant QTL findings (2.0 LOD score intervals; peak; LOD score) came from the TD15 and LD transitions traits, yielding estimated intervals of 2.2 cM for Exq1 (71.3–73.5 cM; peak 72.3 cM; LOD 11.9) and 9.0 cM for Exq4 (29.0–38.2 cM; peak 34 cM; LOD 4.2). The replicated QTLs on Chromosome 1 failed to map in this AIL population. The ISCS data confirmed Exq1 loci in general. However, the ISCS data were complex and less definitive for localizing the Exq1 loci. These exploratory and fear-like behaviors result from inheriting “many small things,” namely, QTL explaining 2%–7% of the phenotypic variance. These results highlight the challenges of positionally cloning loci of small effect for complex traits. In particular, fine-mapping success may depend on the genetic architecture underlying complex traits.Shumin Zhang, Yigong Lou and Howard Gershenfeld contributed equally to this work. Abbreviations: ROI, Region of Interest; RI, recombinant inbred; AIL, advanced intercross line; ISCS, Interval-specific congenic strains; Sqrt, square root; QTL, quantitative trait loci; OF, open field; LOD, likelihood of the odds ratio score; Tde1, traveled distance epoch 1; TDe3, traveled distance epoch 3; TD15, traveled distance during 15 min; VM15, vertical movements during 15 min ; LD, light–dark transitions; AvgCtrT, average center time; Chr, chromosome; Exq, exploratory and excitability QTL.