A physical map of the 1-gigabase bread wheat chromosome 3B

As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17-billion-base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)-based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach.     

Megaparks for metapopulations: Addressing the causes of locally high elephant numbers in southern Africa

Conservation management options for southern African elephants range from local to regional scales. Here we review these options and argue in favour of actions that will deal with the causes rather than symptoms of elephant numbers that are locally high. Metapopulation theory ensures population persistence, while our approach extends this in order to stabilise elephant numbers regionally. By allowing for the development and maintenance of regional sinks, we may also limit numbers in sources. This application of the metapopulation metaphor is a powerful ecological platform from which to manage elephant numbers and impact through southern Africa. Our approach engages the causes of the apparently high abundance of elephants in parts of southern Africa. It moves away from the practice of dealing only with numbers (symptoms) when managing the impact of elephants on other species. While providing an ecological basis for the development of elephant management options, this needs to be melded with social, political and economic realities through southern Africa. In this regard we are encouraged by the ongoing development of several Transfrontier Conservation programmes and Peace Parks across the region.     

Classification of the parenchymal cells in Fasciola gigantica based on ultrastructure and their expression of fatty acid binding proteins (FABPs)

Parenchymal cells in adult Fasciola gigantica can be classified into three types based on their ultrastructural features and different quantities of fatty acid binding protein (FABP) being stored. Parenchymal cell type 1 (Pc1) has pale cytoplasm consisting largely of a loose network of fine fibers, and it contains few mitochondria but numerous glycogen particles. This cell type may be specialized in the storage and metabolism of glycogen and glucose. Parenchymal cell type 2 (Pc2) has similar cytoplasmic features as Pc1 but contains more numerous mitochondria, and high concentration of FABP as reflected by high density of immunostaining and immunogold labeling using specific monoclonal antibody (MoAb) to FABP as probe. Pc2 may, thus, specialize in the storage and metabolism of fatty acids and other lipids. Parenchymal cell type 3 (Pc3) has dense cytoplasm containing large amount of rough endoplasmic reticulum, Golgi complex and mitochondria, which is typical of a secretory cell. Furthermore, Pc3 has very little glycogen particles and is not stained by MoAb against FABP. It could, thus, be concerned with the synthesis of fibers, which form the scaffold of the parenchyma.     

Matrix transformation alters species-area relationships in fragmented coastal forests

Context

Ecological theory suggests that large habitat fragments should harbour more species than small fragments. However, this may depend on the surrounding matrix. Matrices in fragmented landscapes may either amplify or reduce area effects, which could influence predicted extinctions based on species-area relationships (SARs).

Objective

To determine the influence of matrix type on SARs.

Methods

We surveyed birds within 59 coastal forest fragments in two matrix types, anthropogenic (South Africa) and natural (Mozambique). We classified species as forest specialists or habitat generalists and fitted species-area models to compare how SAR slopes differed among matrix types. We also calculated nestedness and evenness to determine if these varied among matrix type and used logistic regressions to identify species-specific responses to matrix type.

Results

For habitat generalists, SARs were weak within both matrices, while for forest specialists it was strong in the anthropogenic but weak in the natural matrix. In the former, the SAR was similar to those recorded for real islands within archipelagos. Forest specialist assemblages were nested by area within anthropogenic, but not natural matrices. Matrix type did not influence evenness. Area only affected the occurrence of one species when the matrix was natural, compared to 11 species when it was anthropogenic.

Conclusions

Forest specialist bird species conformed to island biogeographic predictions of species loss in forest fragments embedded in anthropogenic, but not natural matrices. Extinctions from small forest fragments might be prevented by conserving natural- or restoring anthropogenic matrices, as well as by increasing forest area.

     

Preparation and Characterization of Microcrystalline Cellulose from Sacred Bali Bamboo as Reinforcing Filler in Seaweed-based Composite Film

Microcrystalline cellulose (MCC) isolated from cheap, fast-growing and abundant accessible Sacred Bali bamboo (Schizostachyum brachycladum) was utilized as reinforcement material in the seaweed-based composite film. Isolation of MCC was carried out by using a combination of pulping, bleaching and acid hydrolysis process. This study emphasized on the feasibility of MCC production from Sacred Bali bamboo by studying its properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The commercial-MCC (CMCC) was used as reference material. Results showed that the production yield, moisture content (MC) and fiber length of bamboo-MCC (BMCC) were 83.37±1.48 %, 4.50±0.5 %, and 0.47±0.02 mm, respectively. According to the chemical analysis by FTIR, both lignin and hemicellulose were completely removed from BMCC, and thus, improved the crystallinity (78 %) and thermal stability (≈325 °C) of BMCC. This study also revealed that MCC produced from Sacred Bali bamboo demonstrated strong mechanical reinforcement effect in the seaweed-based film. Hence, Sacred Bali bamboo-MCC could be used as reinforcement material in the polymer.     

Vernalization gene combination to maximize grain yield in bread wheat (Triticum aestivum L.) in diverse environments

The major vernalisation genes of VRN1 are well understood at the molecular level. However, their quantitative contributions to flowering time and grain yield related traits are not clear. In this study, we used a double haploid population (225 lines) of Westonia × Kauz in which the Vrn-A1a (Westonia), Vrn-B1a (Westonia) and Vrn-D1a (Kauz) were segregating, and a high resolution genetic map of 1,159 loci, to determine the quantitative contributions of Vrn-A1a, Vrn-B1a and Vrn-D1a for the days to anthesis and grain yield related traits in diverse environments. The major quantitative trait loci (QTL) of spikelet number per spike and days to anthesis were contributed by the winter alleles of VRN1. The QTL of the time of grain filling were contributed by the spring alleles of VRN1. The wild genotype (vrn-A1vrn-B1vrn-D1) showed the latest flowering, the highest spikelet number per spike, lowest peduncle proportion and thousand grain weight in three environmental analyses, and the largest spikelet number per spike, which resulted in high kernel number per spike (KN) and grain weight (GW) in well-watered environments. One QTL of KN was located on 5B, contributed by winter allele of vrn-B1 in three environmental analyses, and one GW QTL was detected on 5A, contributed by the spring allele of Vrn-A1a in a drought environment. The results indicated that the genotype Vrn-A1avrn-B1Vrn-D1a would shorten the time to anthesis and give high GW and KN in drought environments. The early anthesis associated phenotype, peduncle proportion would provide an indicator in breeding programs.     

Elephant seasonal vegetation preferences across dry and wet savannas

As African savanna elephants (Loxodonta africana) become increasingly confined to smaller fragmented landscapes, concern over their potential detrimental impacts on vegetation and biodiversity has increased. Understanding elephant vegetation preferences across relevant spatial and temporal scales is a critical step towards managing protected areas for the persistence of both elephants and biodiversity. To better understand elephant vegetation selection, we fitted 68 elephants with GPS collars across a strong rainfall gradient spanning seven southern African countries over a period of 6 years. We compared elephant locations with remotely-sensed environmental data that measure bi-monthly vegetation greenness across the study area. Elephants consistently seek out greener than expected vegetation throughout the year. Interestingly, they do so by utilizing vegetation with different phenologies and by selecting landscapes when they are greener than their surroundings. We found no differences between dry and wet savannas. These patterns persist even when elephants are constrained by seasonally available water. In the wet season, elephants select seasonally variable landscapes such as open woodlands, shrublands, and grasslands. These landscapes have a lower average annual greenness but become very green for a few months in the wet season. In the dry season, elephants prefer less variable landscapes that are more consistently green year-round such as well-wooded areas and closed woodlands. Because elephants prefer different vegetation types at different times of the year, small homogeneous protected areas may be unsuitable for elephants. Since elephants prefer woody vegetation during the dry season when they are constrained by water, human actions that increase dry season water availability may contribute to detrimental elephant impacts on vegetation and biodiversity.     

Reduction of (E)-2-nonenal and (E,E)-2,4-decadienal during sourdough fermentation

(E)-2-Nonenal and (E,E)-2,4-decadienal are key aroma compounds in wheat bread crumb. The fate of these unsaturated aldehydes in sourdoughs fermented with homo- and heterofermentative lactobacilli or baker's yeast was investigated, and the metabolic pathways in these microorganisms identified. Clear differences were observed between homofermentative lactobacilli, heterofermentative lactobacilli and Saccharomyces cerevisiae. Heterofermentative strains rapidly reduced the concentrations of these aldehydes in dough, whereas S. cerevisiae displayed a lower activity. Lactobacillus sanfranciscensis reduced the aldehydes to the corresponding unsaturated alcohols, whereas S. cerevisiae reduced both the aldehyde moiety and the double bond, resulting in the formation of the corresponding saturated alcohols. S. cerevisiae first reduced the aldehyde moiety and then the double bond. In L. sanfranciscensis, the reduction of aldehydes is coupled to the oxidation of NADH to NAD⁺, which enables this heterofermentative strain to produce additional ATP from glucose. L. sakei, a strain that produces only lactic acid during sourdough fermentation, did not metabolise the unsaturated aldehydes at all. Both L. sakei and S. cerevisiae appeared to enhance aldehyde formation during the first hours of dough fermentation, probably due to the hydrogen peroxide production by these two strains.     

Differential recovery of lupin proteins from the gluten matrix in lupin-wheat bread as revealed by mass spectrometry and two-dimensional electrophoresis

Bread made from a mixture of wheat and lupin flour possesses a number of health benefits. The addition of lupin flour to wheat flour during breadmaking has major effects on bread properties. The present study investigated the lupin and wheat flour protein interactions during the breadmaking process including dough formation and baking by using proteomics research technologies including MS/MS to identify the proteins. Results revealed that qualitatively most proteins from both lupin and wheat flour remained unchanged after baking as per electrophoretic behavior, whereas some were incorporated into the bread gluten matrix and became unextractable. Most of the lupin α-conglutins could be readily extracted from the lupin-wheat bread even at low salt and nonreducing/nondenaturing extraction conditions. In contrast, most of the β-conglutins lost extractability, suggesting that they were trapped in the bread gluten matrix. The higher thermal stability of α-conglutins compared to β-conglutins is speculated to account for this difference.