Analysis of upland farm households’ vulnerability to climate variability in the Niger Delta, Nigeria

Analysis of upland farm households’ vulnerability - Gabriel, Edet, *Valerie, Glory, Godwin, Clement, Nkoyo, E. Bassey and Obot Analysis of upland farm households’ vulnerability to climate variability in the Niger Delta, Nigeria The study analysed the vulnerability of upland farm households to climate variability in the Niger Delta. Three states - Akwa Ibom, Ondo and Rivers were selected from the nine states that make up the Niger Delta region. A total of 120 respondents from upland communities of the Niger delta were used for analysis. Household questionnaire and vulnerability questionnaire using Cost Route method were the instruments used for data collection and analysed using Vulnerability Profile and Vulner-ability / Risk Framework. The results of the analysis show that both male and female headed house-holds in all the upland communities were vulnerable to flooding, windstorm, erosion and drying up of streams. Important factors that made households vulnerable to climate hazards were low agricultural output and income, non-availability of irrigation facilities, insufficient farm labour and lack of storage facilities. Technical capacities of household members were assessed using both science-based knowledge as well as indigenous knowledge of climate change as indicators to adaptation to climate variability. It was assumed that the adaptive capacity of households could be enhanced by the number of persons with either science-based knowledge or indigenous knowledge across the re-gion. Expenditure on carbohydrate was higher across the region during disaster time, followed by expenditure in protein, vitamin/minerals and fat and oil and other classes of food, implying that more carbohydrate food is consumed during disaster period than any other class of food. Certain geo-graphical factors such as distance to coastline and population have direct impact on climate variability in the Niger Delta Region. Recommendations include establishment of emergency evacuation systems, income opportunities and support programmes as well as capacity building on climate change knowledge, enterprise development and management. Key words: Farm households, Nigeria, poverty, rural areas, smallholder farmer

Transcriptome Analysis of Mouse Stem Cells and Early Embryos

Understanding and harnessing cellular potency are fundamental in biology and are also critical to the future therapeutic use of stem cells. Transcriptome analysis of these pluripotent cells is a first step towards such goals. Starting with sources that include oocytes, blastocysts, and embryonic and adult stem cells, we obtained 249,200 high-quality EST sequences and clustered them with public sequences to produce an index of approximately 30,000 total mouse genes that includes 977 previously unidentified genes. Analysis of gene expression levels by EST frequency identifies genes that characterize preimplantation embryos, embryonic stem cells, and adult stem cells, thus providing potential markers as well as clues to the functional features of these cells. Principal component analysis identified a set of 88 genes whose average expression levels decrease from oocytes to blastocysts, stem cells, postimplantation embryos, and finally to newborn tissues. This can be a first step towards a possible definition of a molecular scale of cellular potency. The sequences and cDNA clones recovered in this work provide a comprehensive resource for genes functioning in early mouse embryos and stem cells. The nonrestricted community access to the resource can accelerate a wide range of research, particularly in reproductive and regenerative medicine

Zscan4: A novel gene expressed exclusively in late 2-cell embryos and embryonic stem cells

The first wave of transcription, called zygotic genome activation (ZGA), begins during the 2-cell stage in mouse preimplantation development and marks a vital transition from the maternal genetic to the embryonic genetic program. Utilizing DNA microarray data, we looked for genes that are expressed only during ZGA and found Zscan4, whose expression is restricted to late 2-cell stage embryos. Sequence analysis of genomic DNA and cDNA clones revealed nine paralogous genes tightly clustered in 0.85 Mb on mouse chromosome 7. Three genes are not transcribed and are thus considered pseudogenes. Among the six expressed genes named Zscan4a-Zscan4f, three - Zscan4c, Zscan4d, and Zscan4f - encode full-length ORFs with 506 amino acids. Zscan4d is a predominant transcript at the late 2-cell stage, whereas Zscan4c is a predominant transcript in embryonic stem (ES) cells. No transcripts of any Zscan4 genes are detected in any other cell types. Reduction of Zscan4 transcript levels by siRNAs delays the progression from the 2-cell to the 4-cell stage and produces blastocysts that fail to implant or proliferate in blastocyst outgrowth culture. Zscan4 thus seems to be essential for preimplantation development

An in situ hybridization-based screen for heterogeneously expressed genes in mouse ES cells

We previously reported that Zscan4 showed heterogeneous expression patterns in mouse embryonic stem (ES) cells. To identify genes that show similar expression patterns, we carried out high-throughput in situ hybridization assays on ES cell cultures for 244 genes. Most of the genes are involved in transcriptional regulation, and were selected using microarray-based comparisons of gene expression profiles in ES and embryonal carcinoma (EC) cells versus differentiated cell types. Pou5f1 (Oct4, Oct3/4) and Krt8 (EndoA) were used as controls. Hybridization signals were detected on ES cell colonies for 147 genes (60%). The majority (136 genes) of them showed relatively homogeneous expression in ES cell colonies. However, we found that two genes unequivocally showed Zscan4-like spotted expression pattern (spot-in-colony pattern; Whsc2 and Rhox9). We also found that nine genes showed relatively heterogeneous expression pattern (mosaic-in-colony pattern: Zfp42/Rex1, Rest, Atf4, Pa2g4, E2f2, Nanog, Dppa3/Pgc7/Stella, Esrrb, and Fscn1). Among these genes, Zfp42/Rex1 showed unequivocally heterogeneous expression in individual ES cells prepared by the CytoSpin. These results show the presence of different types or states of cells within ES cell cultures otherwise thought to be undifferentiated and homogeneous, suggesting a previously unappreciated complexity in ES cell cultures

Assembly, Verification, and Initial Annotation of the NIA Mouse 7.4K cDNA Clone Set

A set of 7407 cDNA clones (NIA mouse 7.4K) was assembled from >20 cDNA libraries constructed mainly from early mouse embryos, including several stem cell libraries. The clone set was assembled from embryonic and newborn organ libraries consisting of ∼120,000 cDNA clones, which were initially re-arrayed into a set of ∼11,000 unique cDNA clones. A set of tubes was constructed from the racks in this set to prevent contamination and potential mishandling errors in all further re-arrays. Sequences from this set (11K) were analyzed further for quality and clone identity, and high-quality clones with verified identity were re-arrayed into the final set (7.4K). The set is freely available, and a corresponding database was built to provide comprehensive annotation for those clones with known identity or homology, and has been made available through an extensive Web site that includes many link-outs to external databases and analysis servers. [The sequence data from this study have been submitted to GenBank under accession nos. BQ550036–BQ563104.

Signature Genes for Specific Groups of Early Embryos and Stem Cells

<p>Signature Genes for Specific Groups of Early Embryos and Stem Cells</p

Examples of NIA-Only cDNA Clones and RT–PCR Results

<p>Expression pattern of 19 novel cDNA clones in 16 different cell lines or tissues: unfertilized egg, E3.5 blastocyst, E7.5 whole embryo (embryo plus placenta), E12.5 male mesonephros (gonad plus mesonephros), newborn brain, newborn ovary, newborn kidney, embryonic germ (EG) cell, embryonic stem (ES) cell (maintained as undifferentiated in the presence of LIF), trophoblast stem (TS) cell, mesenchymal stem (MS) cell, osteoblast, neural stem/progenitor (NS) cell, NS differentiated (differentiated neural stem/progenitor cells), and hematopoietic stem/progenitor (HS) cells. Glyceraldegyde-3-phosphate dehydrogenase (GAP-DH) was used as a control. A U number is assigned to each gene in the gene index (see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0000074#sd002" target="_blank">Dataset S2</a>). The exon number was predicted from alignment with the mouse genome sequence, and the amino acid sequence was predicted with the ORF finder from NCBI.</p

PCA Analysis of EST Frequency

<p>The results were obtained by analyzing 2,812 genes that exceeded 0.1% in at least one library. (A) 3D biplot that shows both cell types (red spheres) and genes (yellow boxes). (B) 2D PCA of cell types. EST frequencies were log-transformed before the analysis. Names of some cells and tissues are abbreviated as follows: 6.5 EP, E6.5 whole embryo (embryo plus placenta); 7.5 EP, E7.5 whole embryo (embryo plus placenta); 8.5 EP, E8.5 whole embryo (embryo plus placenta); 9.5 EP, E9.5 whole embryo (embryo plus placenta); 7.5 E, E7.5 embryonic part only; 7.5 P, E7.5 extraembryonic part only; NbOvary, newborn ovary; NbBrain, newborn brain; NbHeart, newborn heart; NbKidney, newborn kidney; 13.5 VMB, E13.5 ventral midbrain dopamine cells; 12.5 Gonad (F), E12.5 female gonad/mesonephros; 12.5 Gonad (M), E12.5 male gonad/mesonephros; HS (Kit⁻, Sca1⁻), hematopoietic stem/progenitor cells (Lin⁻, Kit⁻, Sca1⁻); HS (Kit⁻, Sca1⁺), hematopoietic stem/progenitor cells (Lin⁻, Kit⁻, Sca1⁺); HS (Kit⁺, Sca1⁻), hematopoietic stem/progenitor cells (Lin⁻, Kit⁺, Sca1⁻); HS (Kit⁺, Sca1⁺), hematopoietic stem/progenitor cells (Lin⁻, Kit⁺, Sca1⁺); and NS-D, differentiated NS cells.</p