Life Sciences Commons^™

Nroc Coordination And Program Delivery, Amanda Stone, Frank Mitchell

PREP Reports & Publications

The primary goal of the Natural Resources Outreach Coalition (NROC) program is to provide education and outreach to communities in the NH Coastal Watersheds that are dealing with the effects of growth, and looking for ways to conserve open spaces and natural resources. Program objectives to meet this goal include: 1. NROC and client communities determine natural resource concerns of the communities. 2. NROC and client communities gather community information about these concerns 3. NROC develops and client communities host community presentations about natural resource-based planning. 4. Communities receive follow up technical and educational assistance as requested. In 2006, NROC …

Juvenile Soft-Shell Clam, Mya Arenaria L.Research In The Hampton-Seabrook Estuary, Brian F. Beal

PREP Reports & Publications

A series of field experiments was conducted at two intertidal sites in the Hampton Seabrook Estuary from November 2004-2006 to assess the efficacy of enhancing intertidal areas with cultured clam (Mya arenaria L.) seed (mean shell length [SL] = 7-10 mm). Measurement variables in each experiment included survival and growth of both cultured and wild seed clams. The first of three trials (November 2004 - May 2005) examined the interactive effects of size of planting area (4 m2, 8 m2, 12 m2, and 18 m2) and predator deterrent netting (none, 4.2 mm, and 6.4 mm aperture [flexible, plastic netting]) at …

Shoreland Buffer Module For Granit Data Mapper, Fay A. Rubin, David G. Justice

PREP Reports & Publications

The Complex Systems Research Center at the University of New Hampshire enhanced the GRANIT Data Mapper (http://mapper.granit.unh.edu) by incorporating data describing shoreline buffers in New Hampshire. The project supports an ongoing, comprehensive New Hampshire Estuaries Project (NHEP) outreach initiative that seeks to educate municipal decision-makers about the importance of stream buffers in preserving water quality in coastal New Hampshire. It complements these existing outreach efforts by allowing coastal managers, local land use boards, and the general public to readily visualize the spatial extent of current and/or proposed shoreline regulations in their community. The primary data source for the analysis was …

Town Of Strafford Nroc Projects, Carolyn Page, Al Pratt, Jeff Schloss, Harmony Anderson

PREP Reports & Publications

The three Strafford committees formed through the work with the Natural Resources Outreach Coalition in 2004 and supported by the grant award from the New Hampshire Estuaries Project have succeeded in furthering land protection, water quality protection, and managing growth here in Strafford. The original NROC meetings brought many new volunteer citizens into the process, but even their enthusiasm and willingness to work could not have earned these results without the financial support of the NHEP grant award. Hours of letter writing and personal contact with landowners by the volunteers of the Land Protection Group have raised awareness of the …

Cadmium Toxicity On Arterioles Vascular Smooth Muscle Cells Of Spontaneously Hypertensive Rats, Benny Washington, Shunta Williams, Patrice Armstrong, Charlie Mtshali, John T. Robinson, Elbert L. Myles

Biology Faculty Research

Cadmium (Cd) is frequently used in various industrial applications and is a ubiquitous environmental toxicant, also present in tobacco smoke. An important route of exposure is the circulatory system whereas blood vessels are considered to be main stream organs of Cd toxicity. Our previous results indicate that cadmium chloride (CdCl2) affects mean arterial blood pressure in hypertensive rats. We hypothesized that Cd alters the intracellular calcium transient mechanism, by cadmium-induced stimulation of MAPKs (ERK 1 & 2) which is mediated partially through calcium-dependent PKC mechanism. To investigate this hypothesis, we exposed primary cultures of vascular smooth muscle cells (VSMCs) from …

Oliver Ranch Science School Complex & Wild Horse And Burro Facility: Final Close-Out Report, Margaret N. Rees

Oliver Ranch Project

“The mission of the Red Rock Desert Learning Center is to instill stewardship and respect by increasing knowledge and understanding of the Mojave Desert ecosystems and cultures through a unique experiential discovery program.”

Lake Mead National Recreation Area Vegetation Monitoring And Management: Quarterly Progress Report, Period Ending December 31, 2006, Margaret N. Rees

Vegetation Monitoring

Executive Summary

• Two new Weed Sentry research assistants were hired.
• Weed Sentry staff surveyed for exotic species on 89 miles of roads on NPS and BLM land and treated more than 21,000 exotic plants in incipient populations.
• A grid-based rare plant monitoring method was tested this quarter.
• A manuscript detailing vegetation succession on a water pipeline at Lake Mead NRA was submitted for review to the journal Crossosoma.
• New integrative projects undertaken this quarter included establishing a competition study between a native grass and the exotic Sahara mustard, salvaging plants for research purposes from private sites with permission from landowners, …

Lake Mead National Recreation Area Monitoring And Evaluation Of Sensitive Wildlife: Quarterly Progress Report, Period Ending December 31, 2006, Margaret N. Rees

Wildlife Monitoring

• Research assistant hired for Relict Leopard Frog conservation project.
• High school minority intern hired to assist with research efforts.
• Nocturnal visual encounter surveys for Relict Leopard Frogs conducted at all established natural sites and at 6 of 7 translocation sites.
• Vegetation management conducted to decrease tamarisk cover along the stream at the Pupfish Refuge Spring – a Relict Leopard Frog translocation site.
• New draft guidelines and field count protocols developed for midwinter bald eagle count.
• Preliminary analysis and modeling of thrasher habitat selection conducted and sampling assessed
• Call-broadcast surveys for thrasher species conducted at 43 points countywide, focusing on vegetation …

Integrated Coastal Spatial Allocation And Planning Of Aquaculture In A Geographical Information System Approach, Andrew Ehiabhi Akhighu

World Maritime University Dissertations

No abstract provided.

Shellfish Tissue Monitoring In New Hampshire Estuaries 2005, Phil Trowbridge

PREP Reports & Publications

Conducted by a committee of Canadian and US government and university scientists, Gulfwatch examines the effects of decades of development and industrialization on the water quality of the Gulf as it relates to human health as well as its impact on other marine organisms. Gulfwatch scientists collect blue mussels at over 60 US and Canadian sites Gulf-wide, and analyze the organisms’ tissue for potentially harmful levels and concentrations of toxins including heavy metals, chlorinated pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). New Hampshire increased the number of Gulfwatch sampling locations from two sites per year in 1997 to …

Varietal Role In The Management Of The Larger Grain Borer, Prostephanus Truncatus (Horn) In Stored Maize, C. P. Rugumamu

Tanzania Journal of Science

The study determined the amount of haemolymph vitellogenin (Vg) of the Larger Grain Borer (LGB), Prostephanus truncatus (Horn) vitellogenic females reared on different maize varieties. The varieties were ZM 521, ZM 421, ECAVL1-DLN, WEEVIL A, LOCAL 1 and LOCAL 2. Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS - PAGE) was conducted on the insect haemolymph. F1 LGB adults from each variety were used to determine Indices of Susceptibility (IS) of the varieties to the insect pest attack. Percentages of Vg from female insects and IS were in the order ZM 521>ZM 421> ECAVL1-DLN>WEEVIL A >LOCAL 1>LOCAL 2. Weight …

Evaluating The Performance Of Leucaena Accessions For Agroforestry In Sub-Humid Environment, Southern Tanzania, A. E. Majule

Tanzania Journal of Science

The performance of Leucaena accessions on acid soils in eastern coast Tanzania for agroforestry was evaluated for three years. Plant tree parameters assessed were fodder yield and plant stem height, stem girth, the number of total branches and poles production. Also, Leucaena psyllid, a common pest threatening the plants was also counted. Soil parameters assessed were pH organic carbon, total nitrogen, exchangeable calcium and magnesium. Result showed significant difference in growth between Leucaena accessions. Leucaena leucocephal cv K8 and Leucaena diversifolia were able to grow fast reaching 4.7 and 3.3 m respectively within a period of three years. Leucaena diversifolia …

Species Richness And Abundance Of Large Mammals In Zaraninge Forest, Coast Region, Tanzania, H. Y. D. Kiwia

Tanzania Journal of Science

A study on the large mammals of Zaraninge Forest was conducted using the line transect method between 1995 and 2001. They comprised 16 species from 7 families, including Bovidae (5), Canidae (1), Cercopithecidae (4), Felidae (1), Galagonidae (2), Orycteropodidae (1) and Suidae (2). Only nine species of primates and antelopes were encountered frequently enough for densities to be estimated. A total of 404 sightings from 40 counts were recorded, the majority being for blue monkey (34.9%) and Angolan colobus (26.0%). For galagos, 210 sightings from 58 counts were recorded, the majority being for Rondo galago (62.2%). Absolute density (individuals km-2) …

Species Richness And Abundance Estimates Of Small Mammals In Zaraninge Coastal Forest In Tanzania, H. Y. D. Kiwia

Tanzania Journal of Science

A study on small mammals (<2 kg) was conducted in Zaraninge Forest, Coast Region, Tanzania, in the dry and wet seasons from 1994 to1996. The forest was found to harbour 11 small mammal species from 11 genera and seven families. There was high similarity in the number of species caught during the two seasons (Sørensen Coefficient (CCs)=0.92), implying there to be minimal migration of the species in the area. A total of 159 individuals were caught during the dry season, rodents accounting for 89.3% of the total catch and insectivores 10.7%. The most common species were Cricetomys gambianus and Grammomys dolichurus that had trap successes of 2.83 and 1.11 respectively. During the wet season 185 animals were caught, rodents accounting for 92.4% of the total catch and insectivores 7.6%. Cricetomys gambianus was significantly more abundant during the dry season. Graphiurus murinus was not caught in this season and no trend in abundance was detected for the other species. Forest specialist species included Paraxerus palliatus and Petrodromus petersi. No species was endemic to the forest, near-endemic species that occur in coastal and Eastern Arc forests included P. petersi and Beamys hindei. B. hindei also occurs in a few other East African forests. Threatened species are B. hindei and P. palliatus that are vulnerable and P. petersi that is endangered. Lepus capensis is in Appendix I of CITES list and Hystrix cristata and Mellivora capensis in Appendix III. The forest, though small is in good health and fairly well protected, therefore the species are not in danger of being locally extinct in the near future.

Assessment Of The Status Of Lates Stappersii (Centropomidae) Stock In Lift-Net Fishery In Lake Tanganyika, Kigoma, Tanzania, I. A. Kimirei, Y. D. Mgaya

Tanzania Journal of Science

An assessment of the status of Lates stappersii (Boulenger, 1914) stock in the lift-net fishery in Lake Tanganyika, Kigoma area, was carried out from January to December 2003. Results indicated that breeding is seasonal with peaks in February, July-August and December, and so was catch composition, with peaks in March, May and July–August that followed the abundance of its prey, Stolothrissa tanganicae. Catch per unit effort was similar between wet and dry seasons and peaked synchronously at all study sites probably as an indication of its abundance during those months; but also it could mean that the fishes were caught …

Ecological And Engineering Importance Of The Bet El Ras Beach-Sandstone, N. Nyandwi, J. W. Kangwe

Tanzania Journal of Science

A unique sandstone known as the Bet el Ras sandstone, supposedly of Holocene age, occurs profusely along the western coast of Unguja but more extensive at its locality area, Bet el Ras, where it forms a rocky shore. The sandstone has been blasted in the past for construction of the sea wall that fronts the Zanzibar Town, and stands to be blasted further for renovation works. From the results of the survey made, it is clear that the sandstone is ecologically and environmentally important such that its total removal will lead to loss of a habitat as well as enhance …

Masking Material As A Form Of Food Storage In Tiarinia Cornigera And Micippa Platipes (Brachyura, Majidae), J. Kyomo

Tanzania Journal of Science

Masking or decorating, which means attaching materials to the body, was investigated in two spider crabs Tiarinia cornigera and Micippa platipesin the subtropical waters of Okinawa, Japan. This life strategy was compared between sites over a period of time. All crabs of different ages and sizes attached materials, in one combination or the other, on their bodies proportionate to their carapace sizes. Older or larger crabs had their carapaces more completely covered with the materials than young or smaller crabs. Similar materials were found at all sites and had equal selective precedences by crabs. Red algae, particularly Gelidiella sp, was …

Vegetation Structure And Heavy Metal Uptake By Plants In The Mining-Impacted And Non Mining-Impacted Sites Of Southern Lake Victoria Wetlands, G. Y. S. Mtui, C. Mligo, M. K. D. Mutakyahwa, J. R. Ikingura

Tanzania Journal of Science

This study assessed the plant species composition and the heavy metal uptake by plants in the mining-impacted and non mining-impacted areas of the southern Lake Victoria basin. The vegetation of the wetlands was stratified into riverine forest, riverine thickets, swampy grassland, open woodland and floodplain grassland. Plant diversity at Nyamtukuza ranged between 2.34 to 2.70; at Geita was 2.29 to 2.57 and Mwakitolyo was between 1.08 to 1.70, which was significantly lower than the other two sites; whereas variation in plant species richness was not significant. TWINSPAN classification resulted into four clusters of the vegetation communities. Cluster A, a shrubby …

Recent Advances In Basic Neurosciences And Brain Disease: From Synapses To Behavior, Guo-Qiang Bi, Vadim Bolshakov, Guojun Bu, Catherine M. Cahill, Zhou-Feng Chen, Graham L. Collingridge, Robin L. Cooper, Jens R. Coorssen, Alaa El-Husseini, Vasco Galhardo, Wen-Biao Gan, Jianguo Gu, Kazuhide Inoue, John Isaac, Koichi Iwata, Zhengping Jia, Bong-Kiun Kaang, Mikito Kawamata, Satoshi Kida, Eric Klann, Tatsuro Kohno, Min Li, Xiao-Jiang Li, John F. Macdonald, Karim Nader, Peter V. Nguyen, Uhtaek Oh, Ke Ren, John C. Roder, Michael W. Salter, Weihong Song, Shuzo Sugita, Shao-Jun Tang, Yuanxiang Tao, Yu Tian Wang, Newton Woo, Melanie A. Woodin, Zhen Yan, Megumu Yoshimura, Ming Xu, Zao C. Xu, Xia Zhang, Mei Zhen, Min Zhuo

Biology Faculty Publications

Understanding basic neuronal mechanisms hold the hope for future treatment of brain disease. The 1st international conference on synapse, memory, drug addiction and pain was held in beautiful downtown Toronto, Canada on August 21-23, 2006. Unlike other traditional conferences, this new meeting focused on three major aims: (1) to promote new and cutting edge research in neuroscience; (2) to encourage international information exchange and scientific collaborations; and (3) to provide a platform for active scientists to discuss new findings. Up to 64 investigators presented their recent discoveries, from basic synaptic mechanisms to genes related to human brain disease. This meeting …

Switchgrass For Biomass Feedstock In The Usa, Matt Sanderson, Paul Adler, Akwasi Boateng, Michael Casler, Gautam Sarath

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Switchgrass has received much study for biomass feedstock production and conversion through research funded by the US-DOE and USDA during the past two decades. We have an improved understanding of the adaptation of existing cultivars and new cultivars with yield and adaptation improvements are now appearing. We also have a good understanding of the agronomics of switchgrass production, mainly from its use as a forage crop. There remain several constraints to switchgrass use in bioenergy cropping systems, including reliable establishment methods to obtain productive stands in the first year, targeted fertilization and nutrient management techniques to efficiently use nitrogen fertilizer, …

Cains Brook And Mill Creek Watershed Management Plan, Town Of Seabrook, Waterfront Engineers, Inc.

PREP Reports & Publications

Cains Brook is a freshwater stream that flows in an easterly direction from its origin—a spring fed pond about one mile west of I-95 on the Salisbury, Massachusetts/Seabrook, New Hampshire border. At its lower reaches the brook is joined by Shepard Brook where it becomes Mill Creek, a tidal creek that discharges into the Hampton-Seabrook estuary. Along its course there are several ponds on either side of US Route 1—Secords, Cains and Mary’s Ponds to the west of Route 1 and Cains Mill Pond and Noyes Pond to the east. This stream system is approximately 3.8 miles long. The Cains …

Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams

All Peer-Reviewed Publications

A survey was conducted in Tororo, Bugiri and Kapchorwa districts in eastern and northeastern Uganda on farmers' perceptions of constraints in maize production. Farmers in Tororo and Bugiri consistently ranked stemborers and striga as the major production constraints in maize growing, while those in Kapchorwa ranked stemborers and lack of capital as the most important. Approximately 35 and 40% of the farmers in Tororo and Bugiri, respectively, identified stemborers as the 'caterpillar' that destroys their maize. In Kapchorwa, 50% of the farmers identified stemborers. Pesticide application was the most common control measure while the use of indigenous and cultural control …

Properties Of Corneal Receptors In A Teleost Fish, Paul J. Ashley, Lynne U. Sneddon, Catherine R. Mccrohan

Veterinary Science and Medicine Collection

Corneal receptors have not previously been identified in lower vertebrates. The present study describes the properties of trigeminal ganglion corneal receptors in a teleost fish, the rainbow trout (Oncoryhnchus mykiss). Out of 27 receptors, 7 were polymodal nociceptors, 6 were mechanothermal nociceptors, 2 were mechanochemical receptors and the largest group, 12, were only responsive to mechanical stimulation. No cold responsive receptors were found on the trout cornea. Mechanical and thermal thresholds were lower and receptive field diameters smaller than those of cutaneous trigeminal receptors in the trout, demonstrating greater sensitivity in the cornea. The lack of cold sensitive neurons may …

Land Conservation Plan For New Hampshire’S Coastal Watersheds – Implementation & Outreach, Mark Zankel

PREP Reports & Publications

The Nature Conservancy was awarded funding to complete activities to promote the Land Conservation Plan for New Hampshire’s Coastal Watersheds in the fall of 2006. The Nature Conservancy and its partners, Society for the Protection of New Hampshire Forests, Rockingham Planning Commission, and Strafford Regional Planning Commission, conducted the following tasks to increase understanding and use of the plan by communities, land trusts and others interested in land protection.

A Predator From East Africa That Chooses Malaria Vectors As Preferred Prey, Ximena J. Nelson, Robert R. Jackson

All Peer-Reviewed Publications

Background. All vectors of human malaria, a disease responsible for more than one million deaths per year, are female mosquitoes from the genus Anopheles. Evarcha culicivora is an East African jumping spider (Salticidae) that feeds indirectly on vertebrate blood by selecting blood-carrying female mosquitoes as preferred prey. Methodology/Principal Findings. By testing with motionless lures made from mounting dead insects in lifelike posture on cork discs, we show that E. culicivora selects Anopheles mosquitoes in preference to other mosquitoes and that this predator can identify Anopheles by static appearance alone. Tests using active (grooming) virtual mosquitoes rendered in 3-D animation show …

Recombinant Watermelon (Citrullus Lanatus) Hydroperoxide Lyase And Uses Thereof, David Hildebrand, Hirotada Fukushige

Plant and Soil Sciences Faculty Patents

Recombinant watermelon (Citrullus lanatus) hydroperoxide lyase protein, DNA sequences encoding the protein, vectors containing the DNA sequences and hosts containing the vectors are provided, together with methods for recombinantly producing watermelon hydroperoxide lyase, DNA sequences, vectors and hosts.

Determinan Indeks Massa Tubuh Remaja Putri Di Kota Bukit Tinggi, Tahun 2006, Rini Santy

Kesmas

Di Indonesia, pada 1999-2003, remaja putri yang mengalami Kekurangan EnergiKronis (KEK). akibat asupan energi yang kurang adalah 35–40% dan sekitar 50% remaja putri menderita status gizi kurang (IMT <18,5 kg/m² ). Tujuan penelitian adalah mengetahui gambaran epidemiologi. IMT remaja putri dan berbagai faktor yang berhubungan Rancangan studi yang digunakan adalah rancangan potong lintang (cross sectional). Populasi adalah remaja putri berusia 16-18 tahun yang tinggal di Buki Tinggi dan sampel adalah 156 siswi kelas III SLTA (SMA, MA, dan SMK) usia 16–18 tahun yang terpilih dari 11 sekola yang diamati. Analisis data dilakukan secara multivariate dengan metoda logistic regression ganda. Hasil penelitian (1) Rata-rata IMT remja putri adalah 20,69 kg/m²± 2,63. (2) Proporsi siswi dengan IMT<18,5 kg/m² adalah 19,9% yang meliputi 14,1% kekurangan gizi ringan dan 5,8% kekurangan gizi berat. (3) Rata-rata asupan energi remaja putri adalah 1,694 kalori dan rata-rata kontribusi terhadap total energi protein (11,8%), lemak (26,7%) dan karbohidrat (58,7%). (4) Rata-rata asupan energi dibanding AKG meliputi total energi (77%), protein (93,6%). Variabel yang berhubungan secara bermakna dengan IMP pada remaja meliputi total energi, kebiasaan makan dan citra tubuh dengan IMT remaja putri dengan variabel utama adalah total energi. In Indonesia, in period of 1999–2003, abot 35–40% women in productive age of 15–19 are at risk of Chronic Energy Deficiency (KEK) because of insufficient consumption of energy. This research is aimed at obtaining the description of nutritional status of girls in Bukittinggi and factors related to it. The research that was conductec in period of February tol March 2006 used the design of cross sectional. The study population is the girls studied are represented by the third-grade female students of senior high schools of 16–18 who are categorized as a late teenager who is very close to pregnant period. The sample consist of 156 female student that was selected by systematic random sampling at 11 schools. The results show that the BMI of the girls is 20.69 kg/m²± 2.63 on average. The proportion of students having BMI <18.5 kg/m2 is 19.9% all of which is distributed to 14.1% of light level of malnutrition and 5.8% for heavy level of malnutrition. Intake per day is 1,694 calorie on average with protein contributed to intake is 11.8%, fat 26.7% dan carbohydrat 58.7%. Intake energy compared with Recommended Dietary Allowence (RDA) are total energy consumption 77%, protein 93.6%, lemak 65.3% and carbohydrat 84.7%. There is a significant relation between energy consumption, eating habit, body image, by BMI. Variable energy consumption is the dominant variable influencing BMI.

Hubungan Pertambahan Berat Badan Selama Kehamilan Dengan Berat Lahir Bayi Di Sukaraja Bogor Tahun 2001- 2003, Elmy Rindang Turhayati

Kesmas

Di Indonesia, pertambahan berat badan selama kehamilan umumnya rendah (<10 >kg), padahal pertambahan berat badan tersebut merupakan indikator pertubuhan janin yang penting. Di Kabupaten Bogor, prevalensi ibu hamil penderita Kurang Energi Kronis (27,6%) adalah tinggi. Penelitian ini bertujuan mengetahui pertambahan berat badan selama kehamilan dan hubungannya dengan berat badan bayi baru lahir. Penelitian dengan disain potong lintang ini dilakukan pada 270 sampel ibu hamil yang melahirkan cukup bulan (>37 minggu), mengunakan metoda Regresi Logistik. Ditemukan proporsi bayi lahir dengan berat 2.500-2.999 gram adalah 47,8%. Rata-rata berat lahir adalah 3.015 gram. Proporsi ibu dengan pertambahan berat badan selama kehamilan 48,9%. …

The Plant Structure Ontology, A Unified Vocabulary Of Anatomy And Morphology Of A Flowering Plant, Katica Ilic, Elizabeth Kellogg, Pankaj Jaiswal, Felipe Zapata, Peter Stevens, Leszek Vincent, Shulamit Avraham, Leonore Reiser, Anuradha Pujar, Martin Sachs, Noah Whitman, Susan Mccouch, Mary Schaeffer, Doreen Ware, Lincoln Stein, Seung Rhee

Biology Department Faculty Works

Formal description of plant phenotypes and standardized annotation of gene expression and protein localization data require uniform terminology that accurately describes plant anatomy and morphology. This facilitates cross species comparative studies and quantitative comparison of phenotypes and expression patterns. A major drawback is variable terminology that is used to describe plant anatomy and morphology in publications and genomic databases for different species. The same terms are sometimes applied to different plant structures in different taxonomic groups. Conversely, similar structures are named by their species-specific terms. To address this problem, we created the Plant Structure Ontology (PSO), the first generic ontological …

Untemplated Oligoadenylation Promotes Degradation Of Risc-Cleaved Transcripts, Fadia Ibrahim, Jennifer Rohr, Won-Joong Jeong, Jennifer Hesson, Heriberto D. Cerutti

Center for Plant Science Innovation: Faculty Publications

In the best-characterized mechanism of RNAmediated silencing, small interfering RNAs (siRNAs), incorporated into the RNA-induced silencing complex (RISC), guide the endonucleolytic cleavage of complementary RNAs (1). In Drosophila melanogaster, these RISC-generated products are eventually degraded by exoribonucleases: Xrn1, a 5′-to-3′ exonuclease, and exosome, a 3′-to-5′ multisubunit exonuclease (2). Interestingly, in Arabidopsis thaliana and in mammals, an oligouridine or oligoadenine [oligo(U/A)] tail is added to the 5′ RNA fragments resulting from microRNA-directed cleavage (3). However, the biological role of this tail remains unclear.