Ecosystem services and drivers of change in Nyando floodplain wetland, Kenya

Papyrus wetlands in East Africa play a vital role in supporting livelihoods of people living around them. Although, subject to natural fluctuations and threats by anthropogenic activities, little is known about historical changes in wetland functions and services, or their present status. We focused on Nyando wetland on the eastern shores of Lake Victoria, Kenya. Three sites in the wetland were identified for assessment of history and current status. Changes during the past fifty years were assessed through participatory exercises with local communities and a review of published work. To establish the current status, we used field surveys and transect walks. Results showed that the wetland is important for hydrological and also ecological functions, which depend on the connectivity of the wetland with river and lake. The major direct drivers of change were hydrological regimes and livelihood activities. The main indirect driver of change was population growth, which leads to more pressure on wetland resources. Provisioning services are important in Nyando wetland but are generated at the expense of regulating services. Hydrology and livelihoods are strongly interlinked as flooding limits access to the wetland. Understanding the historical changes in wetland functions and services is important for rural communities, policy makers and for wetland managers in guiding, planning and wetland management.Key words: Papyrus wetland, wetland ecosystem services, drivers of change, community perception, Nyando wetland

Incorporating an Environmental Management Plan in Water Utilities Management Systems to Reduce Water Loss; Case of Non-Revenue Water in Kisumu City, Kenya

One of the biggest issues facing water utilities is the water loss experienced during the distribution process. This study sought to examine water distribution process in Kisumu and formulate an Environmental Management Plan (EMP) to minimize water loss and mitigate their negative environmental impacts. A qualitative research approach and a case study research design were employed where 25 participants from Kisumu Water and Sanitation Company (KIWASCO) were interviewed in a Focus Group Discussion (FGD). Content analysis of the data collected indicated that water quality and quantity were greatly affected by water loss and the problems associated with them included water pollution due to introduction of contaminants when leakages or pipe bursts occur and water scarcity where the water utility was unable to make up for the amount of water lost. Water abstraction technique was also identified as a vital factor that determines how much water is lost even before it gets into the distribution system. Land/soil, socioeconomic and political environment were also some of the factors identified as they form the backbone of a functional EMP. The research concluded that as much as KIWASCO has a strategic plan to minimize these water losses, the goal entirely focuses on doing so for economic gains and not to address the associated negative environmental impacts hence the recommendation that there is need to incorporate an EMP in their management systems that will not only ensure high revenue generation but also guarantee the conservation of the said water resource to achieve environmental excellence

Kmt2c mutations enhance HSC self-renewal capacity and convey a selective advantage after chemotherapy

The myeloid tumor suppressor KMT2C is recurrently deleted in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), particularly therapy-related MDS/AML (t-MDS/t-AML), as part of larger chromosome 7 deletions. Here, we show that KMT2C deletions convey a selective advantage to hematopoietic stem cells (HSCs) after chemotherapy treatment that may precipitate t-MDS/t-AML. Kmt2c deletions markedly enhance murine HSC self-renewal capacity without altering proliferation rates. Haploid Kmt2c deletions convey a selective advantage only when HSCs are driven into cycle by a strong proliferative stimulus, such as chemotherapy. Cycling Kmt2c-deficient HSCs fail to differentiate appropriately, particularly in response to interleukin-1. Kmt2c deletions mitigate histone methylation/acetylation changes that accrue as HSCs cycle after chemotherapy, and they impair enhancer recruitment during HSC differentiation. These findings help explain why Kmt2c deletions are more common in t-MDS/t-AML than in de novo AML or clonal hematopoiesis: they selectively protect cycling HSCs from differentiation without inducing HSC proliferation themselves

The efficiency of murine MLL-ENL–driven leukemia initiation changes with age and peaks during neonatal development

MLL rearrangements are translocation mutations that cause both acute lymphoblastic leukemia and acute myeloid leukemia (AML). These translocations can occur as sole clonal driver mutations in infant leukemias, suggesting that fetal or neonatal hematopoietic progenitors may be exquisitely sensitive to transformation by MLL fusion proteins. To test this possibility, we used transgenic mice to induce one translocation product, MLL-ENL, during fetal, neonatal, juvenile and adult stages of life. When MLL-ENL was induced in fetal or neonatal mice, almost all died of AML. In contrast, when MLL-ENL was induced in adult mice, most survived for >1 year despite sustained transgene expression. AML initiation was most efficient when MLL-ENL was induced in neonates, and even transient suppression of MLL-ENL in neonates could prevent AML in most mice. MLL-ENL target genes were induced more efficiently in neonatal progenitors than in adult progenitors, consistent with the distinct AML initiation efficiencies. Interestingly, transplantation stress mitigated the developmental barrier to leukemogenesis. Since fetal/neonatal progenitors were highly competent to initiate MLL-ENL-driven AML, we tested whether Lin28b, a fetal master regulator, could accelerate leukemogenesis. Surprisingly, Lin28b suppressed AML initiation rather than accelerating it. This may explain why MLL rearrangements often occur before birth in human infant leukemia patients, but transformation usually does not occur until after birth, when Lin28b levels decline. Our findings show that the efficiency of MLLENL- driven AML initiation changes through the course of pre- and postnatal development, and developmental programs can be manipulated to impede transformation

Annual cycle of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) in southwestern Burkina Faso

Maruca vitrata is an economically significant insect pest of cowpea in sub-Saharan Africa. Understanding the seasonal population patterns of M. vitrata is essential for the establishment of effective pest management strategies. M. vitrata larval populations on cultivated cowpea and adult flying activities were monitored in addition to scouting for host plants and parasitoids during 2 consecutive years in 2010 and 2011 in southwestern Burkina Faso. Our data suggest that M. vitrata populations overlapped on cultivated cowpea and alternate host plants during the rainy season. During the cowpea off-season, M. vitrata maintained a permanent population on the wild host plants Mucuna poggei and Daniella oliveri. The parasitoid fauna include three species, Phanerotoma leucobasis Kri., Braunsia kriegeri End. and Bracon sp. Implications of these finding for pest management strategies are discussed

Recurrent mutations in the U2AF1 splicing factor in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are hematopoietic stem cell disorders that often progress to chemotherapy-resistant secondary acute myeloid leukemia (sAML). We used whole-genome sequencing to perform an unbiased comprehensive screen to discover the somatic mutations in a sample from an individual with sAML and genotyped the loci containing these mutations in the matched MDS sample. Here we show that a missense mutation affecting the serine at codon 34 (Ser34) in U2AF1 was recurrently present in 13 out of 150 (8.7%) subjects with de novo MDS, and we found suggestive evidence of an increased risk of progression to sAML associated with this mutation. U2AF1 is a U2 auxiliary factor protein that recognizes the AG splice acceptor dinucleotide at the 3' end of introns, and the alterations in U2AF1 are located in highly conserved zinc fingers of this protein. Mutant U2AF1 promotes enhanced splicing and exon skipping in reporter assays in vitro. This previously unidentified, recurrent mutation in U2AF1 implicates altered pre-mRNA splicing as a potential mechanism for MDS pathogenesis

An assessment of the risk of Bt-cowpea to non-target organisms in West Africa

Cowpea (Vigna unguiculata Walp.) is the most economically important legume crop in arid regions of sub-Saharan Africa. Cowpea is grown primarily by subsistence farmers who consume the leaves, pods and grain on farm or sell grain in local markets. Processed cowpea foods such as akara (a deep-fat fried fritter) are popular in the rapidly expanding urban areas. Demand far exceeds production due, in part, to a variety of insect pests including, in particular, the lepidopteran legume pod borer (LPB) Maruca vitrata. Genetically engineered Bt-cowpea, based on cry1Ab (Event 709) and cry2Ab transgenes, is being developed for use in sub-Saharan Africa to address losses from the LBP. Before environmental release of transgenic cowpeas, the Bt Cry proteins they express need to be assessed for potential effects on non-target organisms, particularly arthropods. Presented here is an assessment of the potential effects of those Cry proteins expressed in cowpea for control of LPB. Based on the history of safe use of Bt proteins, as well as the fauna associated with cultivated and wild cowpea in sub-Saharan Africa results indicate negligible effects on non-target organisms

Allele-Specific Effects of U2AF1 Mutations on Alternative Splicing

Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders characterized by dysplastic blood cell formation and peripheral blood cytopenias. Up to 30% of patients with MDS will progress to a highly chemotherapy-resistant secondary acute myeloid leukemia (sAML). Four independent groups, including ours, have previously discovered spliceosome mutations in MDS samples using unbiased sequencing approaches (up to 57% of patients carry a mutation in 1 of 8 spliceosome genes). We used whole genome sequencing to identify novel mutations in the genomes of 15 patients with secondary AML that had progressed from de novo MDS and identified a novel recurrent point mutation affecting the same codon (serine at amino acid position 34) in the U2AF1 gene in 3/15 samples. Using total exonic resequencing of U2AF1 in 150 de novo MDS samples, we identified mutations affecting the S34 and Q157 codons in 18/150 (11%) samples. Apart from our group, recent reports have also confirmed the presence of U2AF1 mutations in MDS and AML patients; S34F, S34Y, Q157R and Q157P. Although the role of U2AF1 as an accessory factor in the U2 snRNP is well established, it is not yet clear how these mutations affect splicing or contribute to MDS. We found that recurrent mutations in U2AF1 have allele-specific effects on alternative splicing (AS). U2AF1 (S34F) localizes normally within the nuclear speckles and co-localizes with U2AF2. However, the direct interaction of U2AF1 (S34F) with other components of the spliceosome is reduced. The global gene expression pattern of CD34+ hematopoietic cells defined by RNA-seq is not perturbed by U2AF1 (S34F); however, analysis of splice junctions revealed significant differences in the abundance of known and novel junctions in samples transfected with U2AF1 (S34F). These differences reflected alterations in exon skipping, alternative site usage and other splicing events. For selected transcripts, splicing alterations detected by RNA-seq were confirmed by analysis of primary de novo MDS patient samples. These data suggest that the S34F mutation affects U2AF1 function, leading to aberrant AS of target genes, some of which may be relevant for MDS pathogenesis