Vitamin B12 Status in Pregnancy among Immigrants to Britain

Haemoglobin, serum vitamin B₁₂, and serum and red cell folate levels have been measured in 322 pregnant immigrant women in London at their first booking and in a proportion at 34 weeks of gestation and postnatally. The Indian, East-African Indian, and Pakistani and Bangladeshi patients showed significantly lower initial mean serum vitamin B₁₂ levels than the European group, the levels being lower in Hindu and Sikh patients than in Moslems. The patients of West Indian, Indian, and East-African Indian origin showed significantly lower initial mean haemoglobin levels than the immigrants from European countries. Though there was no overall correlation between haemoglobin and serum vitamin B₁₂ level the incidence of hypersegmented polymorphs and macrocytosis in the peripheral blood was highest in the Indian and East-African Indian patients, and both these features were particularly frequent in patients with subnormal serum vitamin B₁₂ levels. Only one patient, however, had overt megaloblastic anaemia due to vitamin B₁₂ deficiency. The Indian patients whose red cell folate levels were less than 200 ng/ml also had a lower mean serum vitamin B₁₂ level than those with red cell folate levels greater than 200 ng/ml. The Indian patients had smaller babies than the Europeans but this was not related to the differences in vitamin B₁₂ status between the two groups. However, out of 39 babies of the Indian group 5 (13%) showed subnormal serum vitamin B₁₂ levels in the first 10 days of life, the lowest level being 120 pg/ml.Though there was an overall statistically significant fall in serum vitamin B₁₂ between first booking and 34 weeks of pregnancy there was no significant fall in serum vitamin B₁₂ in those who initially had subnormal levels. Thus many Indian women are vitamin B₁₂ deficient in pregnancy, and this is associated with morphological blood abnormalities in many cases, but megaloblastic anaemia due to this deficiency is relatively infrequent.     

Chaetomium elatum (Kunze: Chaetomiaceae) as a root-colonizing fungus in avocado: is it a mutualist, cheater, commensalistic associate, or pathogen?

Plants support numerous root colonists that may share morphological characteristics with mycorrhizal fungi but may play different roles in the rhizosphere. To determine the function of one such root-colonizing fungus, Chaetomium elatum, the infectivity and composition of inoculum containing C. elatum were varied independently of and in association with the known mutualist Glomus intraradices under two light intensities. Maximum plant benefit occurred with mixtures of both G. intraradices and C. elatum and under high light intensity. Under low light intensity and in monoculture, C. elatum functioned as a weak pathogen that was able to kill host plants. Here, maximum plant mortality was associated with the highest levels of C. elatum infectivity. When G. intraradices was present, no negative impact of C. elatum was detected. Intraspecific interactions were important in predicting sporulation rates for both fungi, whereas no interspecific fungal interactions were detected. In the presence of G. intraradices, C. elatum appears to function as a "commensalistic associate," neither impacting plant growth nor sporulation by G. intraradices. Overall, C. elatum appears to be multifunctional, serving as both a rhizoplane and rhizophere fungus, opportunistically colonizing plant roots and only becoming pathogenic when resources are severely limited and intraspecific competition is high. This multifunctional strategy may be shared with other fungi that form similar structures in roots.     

Over‐expression of specific HvCslF cellulose synthase‐like genes in transgenic barley increases the levels of cell wall (1,3;1,4)‐β‐d‐glucans and alters their fine structure

Cell walls in commercially important cereals and grasses are characterized by the presence of (1,3;1,4)‐β‐d ‐glucans. These polysaccharides are beneficial constituents of human diets, where they can reduce the risk of hypercholesterolemia, type II diabetes, obesity and colorectal cancer. The biosynthesis of cell wall (1,3;1,4)‐β‐d ‐glucans in the Poaceae is mediated, in part at least, by the cellulose synthase‐like CslF family of genes. Over‐expression of the barley CslF6 gene under the control of an endosperm‐specific oat globulin promoter results in increases of more than 80% in (1,3;1,4)‐β‐d ‐glucan content in grain of transgenic barley. Analyses of (1,3;1,4)‐β‐d ‐glucan fine structure indicate that individual CslF enzymes might direct the synthesis of (1,3;1,4)‐β‐d ‐glucans with different structures. When expression of the CslF6 transgene is driven by the Pro35S promoter, the transgenic lines have up to sixfold higher levels of (1,3;1,4)‐β‐d ‐glucan in leaves, but similar levels as controls in the grain. Some transgenic lines of Pro35S:CslF4 also show increased levels of (1,3;1,4)‐β‐d ‐glucans in grain, but not in leaves. Thus, the effects of CslF genes on (1,3;1,4)‐β‐d ‐glucan levels are dependent not only on the promoter used, but also on the specific member of the CslF gene family that is inserted into the transgenic barley lines. Altering (1,3;1,4)‐β‐d ‐glucan levels in grain and vegetative tissues will have potential applications in human health, where (1,3;1,4)‐β‐d ‐glucans contribute to dietary fibre, and in tailoring the composition of biomass cell walls for the production of bioethanol from cereal crop residues and grasses.     

Gene expression changes in phosphorus deficient potato (Solanum tuberosum L.) leaves and the potential for diagnostic gene expression markers

Background

There are compelling economic and environmental reasons to reduce our reliance on inorganic phosphate (Pi) fertilisers. Better management of Pi fertiliser applications is one option to improve the efficiency of Pi fertiliser use, whilst maintaining crop yields. Application rates of Pi fertilisers are traditionally determined from analyses of soil or plant tissues. Alternatively, diagnostic genes with altered expression under Pi limiting conditions that suggest a physiological requirement for Pi fertilisation, could be used to manage Pifertiliser applications, and might be more precise than indirect measurements of soil or tissue samples.

Results

We grew potato (Solanum tuberosum L.) plants hydroponically, under glasshouse conditions, to control their nutrient status accurately. Samples of total leaf RNA taken periodically after Pi was removed from the nutrient solution were labelled and hybridised to potato oligonucleotide arrays. A total of 1,659 genes were significantly differentially expressed following Pi withdrawal. These included genes that encode proteins involved in lipid, protein, and carbohydrate metabolism, characteristic of Pi deficient leaves and included potential novel roles for genes encoding patatin like proteins in potatoes. The array data were analysed using a support vector machine algorithm to identify groups of genes that could predict the Pi status of the crop. These groups of diagnostic genes were tested using field grown potatoes that had either been fertilised or unfertilised. A group of 200 genes could correctly predict the Pi status of field grown potatoes.

Conclusions

This paper provides a proof-of-concept demonstration for using microarrays and class prediction tools to predict the Pi status of a field grown potato crop. There is potential to develop this technology for other biotic and abiotic stresses in field grown crops. Ultimately, a better understanding of crop stresses may improve our management of the crop, improving the sustainability of agriculture.     

Autism and intellectual disability are differentially related to sociodemographic background at birth

Background

Research findings investigating the sociodemographics of autism spectrum disorder (ASD) have been inconsistent and rarely considered the presence of intellectual disability (ID).

Methods

We used population data on Western Australian singletons born from 1984 to 1999 (n = 398,353) to examine the sociodemographic characteristics of children diagnosed with ASD with or without ID, or ID without ASD compared with non-affected children.

Results

The profiles for the four categories examined, mild-moderate ID, severe ID, ASD without ID and ASD with ID varied considerably and we often identified a gradient effect where the risk factors for mild-moderate ID and ASD without ID were at opposite extremes while those for ASD with ID were intermediary. This was demonstrated clearly with increased odds of ASD without ID amongst older mothers aged 35 years and over (odds ratio (OR) = 1.69 [CI: 1.18, 2.43]), first born infants (OR = 2.78; [CI: 1.67, 4.54]), male infants (OR = 6.57 [CI: 4.87, 8.87]) and increasing socioeconomic advantage. In contrast, mild-moderate ID was associated with younger mothers aged less than 20 years (OR = 1.88 [CI: 1.57, 2.25]), paternal age greater than 40 years (OR = 1.59 [CI: 1.36, 1.86]), Australian-born and Aboriginal mothers (OR = 1.60 [CI: 1.41, 1.82]), increasing birth order and increasing social disadvantage (OR = 2.56 [CI: 2.27, 2.97]). Mothers of infants residing in regional or remote areas had consistently lower risk of ASD or ID and may be linked to reduced access to services or under-ascertainment rather than a protective effect of location.

Conclusions

The different risk profiles observed between groups may be related to aetiological differences or ascertainment factors or both. Untangling these pathways is challenging but an urgent public health priority in view of the supposed autism epidemic.     

Regulatory hotspots are associated with plant gene expression under varying soil phosphorus supply in Brassica rapa

Gene expression is a quantitative trait that can be mapped genetically in structured populations to identify expression quantitative trait loci (eQTL). Genes and regulatory networks underlying complex traits can subsequently be inferred. Using a recently released genome sequence, we have defined cis- and trans-eQTL and their environmental response to low phosphorus (P) availability within a complex plant genome and found hotspots of trans-eQTL within the genome. Interval mapping, using P supply as a covariate, revealed 18,876 eQTL. trans-eQTL hotspots occurred on chromosomes A06 and A01 within Brassica rapa; these were enriched with P metabolism-related Gene Ontology terms (A06) as well as chloroplast- and photosynthesis-related terms (A01). We have also attributed heritability components to measures of gene expression across environments, allowing the identification of novel gene expression markers and gene expression changes associated with low P availability. Informative gene expression markers were used to map eQTL and P use efficiency-related QTL. Genes responsive to P supply had large environmental and heritable variance components. Regulatory loci and genes associated with P use efficiency identified through eQTL analysis are potential targets for further characterization and may have potential for crop improvement.     

Enzymatic synthesis of chiral amino‐alcohols by coupling transketolase and transaminase‐catalyzed reactions in a cascading continuous‐flow microreactor system

Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino‐alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)‐2‐amino‐1,3,4‐butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non‐chiral starting materials, by coupling a transketolase‐ and a transaminase‐catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor‐based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous‐flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase‐catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml^?1. Following optimization of the transaminase‐catalyzed reaction, a volumetric activity of 10.8 U ml^?1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous‐flow microreactors can be applied for the design and optimization of biocatalytic processes.

     

Indoleamine 2,3-dioxygenase 2 (IDO2) and the kynurenine pathway: characteristics and potential roles in health and disease

The kynurenine pathway is the major route for the oxidative degradation of the amino acid tryptophan. Activity of the pathway is involved in several disease conditions, both in the periphery and the central nervous system, including cancer, inflammatory disorders, neurological conditions, psychiatric disorders and neurodegenerative diseases. Three enzymes are now known to catalyze the first and rate-limiting step in the catabolism of tryptophan along this pathway: tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO, subsequently named IDO1), both of which have been extensively studied, and a third enzyme, indoleamine 2,3-dioxygenase 2 (IDO2), a relative newcomer to the kynurenine pathway field. The adjuvant chemotherapeutic agent, 1-methyl-d-tryptophan, was intially suggested to target IDO2, implying involvement of IDO2 in tumorigenesis. Subsequently this compound has been suggested to have alternative actions and the physiological and pathophysiological roles of IDO2 are unclear. Targeted genetic interventions and selective inhibitors provide approaches for investigating the biology of IDO2. This review focuses on the current knowledge of IDO2 biology and discusses tools that will assist in further characterizing the enzymes of the kynurenine pathway.     

Seasonal fluctuations of zooplankton biomass in Lake Xolotlán (Managua)

Seasonal fluctuations of zooplankton biomass (dry weight) were determined during a year in two localities of Lake Xolotlán (Managua). Biomass estimations of the most common species of rotifers, cladocerans and copepods were made. The maximal zooplankton biomass was observed in February–April (dry season) in coincidence with the period of highest phytoplankton abundance. Copepods contributed with 78% and 84% to the mean zooplankton biomass at points 1 and 7, respectively. Cladocera biomass was lowest during most of the year, and it was probably controlled by fish predation. Development of rotifer biomass was more intense during the rainy season, when detritus particles were more abundant. Daily fluctuations of zooplankton biomass were not pronounced.