Two new roles for the TYMV tRNA-like structure : translation enhancement and repression of minus strand synthesis

Some positive-strand RNA plant viruses possess a transfer RNA-like structure (TLS) at the 3'-terminus of their genomic RNAs. The closest mimicry to tRNA is exhibited by the valylatable TLSs from tymoviruses and furo-like viruses, which are able to interact with key cellular tRNA enzymes: [CTP, ATP]:tRNA nucleotidyltransferase (CCA NTase), valyl-tRNA synthetase (ValRS), and translation elongation factor 1A (eEF1A). In this thesis, I report the discovery of two new roles of the Turnip yellow mosaic tymovirus TLS, in translation enhancement (Chapter 2) and repression of minus strand initiation (Chapter 4). Placement of the 3'-terminal 109 nts of TYMV RNA in a luciferase reporter RNA with a generic 5'-UTR enhanced translation by about 20-fold in cowpea protoplasts. Exhibiting a synergistic relationship with the 5'-cap, the 3'-translation enhancement was largely dependent on the aminoacylatability of the TLS and apparently on eEF1A interaction. In the presence of the 5'-UTR from genomic TYMV RNA, translation of both the overlapping proteins p69 and p206 was strongly dependent on a 5'-cap structure, and was enhanced by the 3'-enhancer. These in vivo results contradict the proposed model in which translation initiation of p206, but not p69, is cap-independent and TLS-dependent (Barends et al. Cell 112(2003):123-9). In vitro experiments with a partially purified preparation of TYMV replicase have investigated the phenomenon of minus strand repression. Interaction of purified eEF1A•GTP specifically with the valylated TLS decreased the template activity for minus strand to near-background levels. eEF1A•GTP acts by making the 3'-CCA minus strand initiation site unavailable to the replicase. The influence of eEF1A in simultaneously enhancing translation and repressing minus strand synthesis can be considered a regulation that ensures robust translation early in the infection and that offers a coordinated transition from translation to replication. Previously shown to be critical for TYMV infectivity, a valylatable TLS was investigated for its role in the replication and infectivity of the bipartite Peanut clump pecluvirus. A valylatable TLS provided a small competitive advantage in protoplasts and whole plants. The advantage was more apparent in protoplasts than in whole plants, and more so in the replication protein-encoding RNA1 than in the trans-replicating RNA2

Inland fisheries and Livelihoods of the Mayan Zone in Quintana Roo, Mexico

This paper reports on the first comprehensive study of economic and livelihood considerations relating to inland fisheries in common property lands (ejidos) of the Mayan Zone in Quintana Roo, Mexico. Given the data-sparse nature of these fisheries, a fishery assessment approach was used which linked methods from both the natural and social sciences, and which combined the local knowledge of community residents with scientific knowledge. The results, from 48 fishing sites in 9 ejidos, showed that the fisheries involve both indigenous (Mayan) and non-indigenous fishers, and is mainly male oriented, although with some women involved in the majority of ejidos studied. A comparison with other sources of livelihood showed that for most involved in fishing, the major occupation was slash-and-burn agriculture. The fisheries are highly artisanal (small-scale) with very basic technology (notably hand-lines) utilized primarily through barefoot fishing along the shores, or with the aid of rafts and canoes, and taking place seasonally, primarily during the dry season. While the key motivation of those in the fishery was subsistence, the study found, for the first time in this form of fishery, that recreation was also a significant goal of many participants.Keywords: Common property lands, Fishery assessment, Fisheries Development, Fisheries Economics, Inland fisheries, Quintana Roo, Mexic

Short lived bacterial regulatory proteins : what determines their fate?

Rapid degradation of certain short lived "timing" proteins is an effective mechanism for cells to control important regulatory pathways. The mechanisms by which regulatory proteases recognize their substrates are not well understood. Escherichia coli Lon, an energy dependent protease highly conserved in many prokaryotes and eukaryotes provides a model system to study protease/substrate interactions. RcsA, a regulator of capsule synthesis, when present in levels high enough to saturate Lon, cannot protect SulA, a cell division inhibitor, from being degraded. These observations suggest Lon recognizes its different substrates with different affinities. The different affinities of these substrates might relate to the role these substrates play in the cell: stabilization of RcsA leads to a nonlethal phenotype (capsule), while stabilization of SulA leads to lethal filamentation. To further examine protease/substrate interactions, targeted mutagenesis was employed to select for mutations in rcsA which give rise to mutant RcsA protein no longer degraded by Lon protease. Two mutants with an increased half-life in the presence of Lon were identified. Their mutations fall into the C-terminal region of RcsA, supporting the hypothesis that this region is involved in the interaction of RcsA with Lon. Stabilization of RcsA was dependent on its partner RcsB; the interaction of RcsA with RcsB is believed to protect RcsA from Lon dependent degradation. However, it was shown that rcsA expression is enhanced in the presence of RcsB, and RcsA protein cannot be detected in strains mutant for RcsB in the presence or absence of Lon. Furthermore, rcsA expression was shown to be activated by RcsA itself: rcsA::lacZ expression is low in the absence of RcsA. A conserved 25 by motif, designated "RcsA-Box" was identified in the promoter region of the rcsA and capsule (cps) genes. This motif was shown to be a likely candidate for RcsA binding: high level expression of both cps::lacZ and rcsA::lacZ fusions was shown to be dependent on the presence of the "RcsA-Box". These studies expand the understanding of the specific interactions between regulatory proteases and their targets, specifically as they relates to complex regulatory networks

Differentials among single-unit owner-occupied homes recently remodeled in Corvallis, Oregon

The purpose of this study was to investigate the home remodeling being done during a period of varying economic conditions. A population of owner-occupants who had purchased building permits to spend $100 or more remodeling between 1965 - 1970 was collected from the files of the Building Inspector's Office, Department of Public Works, City of Corvallis. The Corvallis city directories for the years 1965 1970 were used to check if the remodeled houses were owner-occupied as well as who occupied them at the time of remodeling, and in 1970. This list was further checked with the most recent Corvallis telephone directory for spelling of names and addresses. A questionnaire developed for the study was mailed to 320 households. Of these, 121 usable questionnaires were returned. The responses to the questions were coded, tabulated, and summarized by the researcher. The following hypotheses were tested: 1. There is no relationship between the annual rate of interest charged for money borrowed and the total amount spent on remodeling. 2. There is no relationship between the monetary value of the house and the amount of money spent in the remodeling of it. 3. There is no relationship between the stage in the family life cycle and the type of remodeling done to the house. On the basis of the chi- square test results none of the hypotheses could be rejected. Families were classified and placed in one of the following six stages of the family life cycle: young couple, founding, expanding, contracting, contracted, and other families. Of the 121 households returning the questionnaire, 55 percent were in the expanding stage, 14 percent were in the contracted stage, 10 percent were in the other stage, nine percent were in the founding stage, eight percent were in the contracting stage, and one percent was in the young couple stage. Data on three percent of the population were not sufficient to classify by stage in the family life cycle. The United States Department of Labor's Dictionary of Occupational Titles was used to classify the occupations of the respondents. Sixty-six percent of the 114 men and 49 percent of the 53 employed women were in professions. The average age of the women was 44 years, and the average age of the men was 47 years. The average age of the sons and of the daughters was 12 years. The average size of the household was 4.07. Sixty-three percent of the households remained the same size from the time of their remodeling through the time of the study. Seventeen percent of the households increased in size, and 20 percent of the households decreased in size from the time of their remodeling to the time of the study. Most of the families financed their remodeling with their current income and/or savings. The first remodeling was usually an addition to the home, and was more expensive than the second or third remodeling. The second remodeling was usually an alteration. A building contractor did most of the first remodeling, but family labor was also used. The husband and other family members contributed more assistance to the second and third remodelings. The average market value of the houses at the time of remodeling was$17, 784. The houses most often remodeled were built between 1957 and 1961, and had been occupied for about nine years by the families who remodeled them between the fifth and ninth years of occupancy. Families who remodeled felt that it was important that their present home provided privacy for family members and storage space. They wanted to improve their homes by remodeling the space for leisure-time and work activities, storage space, and privacy. Families were limited in their remodeling by the amount of space available and money they wanted to spend or borrow. Only 53 of the 121 families borrowed money to remodel. They paid an average interest rate of 6.47 percent per annum. A Federal Housing Administration insured mortgage from a bank was the most often used source of borrowed money

Behavioral responses underpinning resistance and susceptibility of honeybees to Tropilaelaps mercedesae

Behavioral responses of Apis cerana, Apis dorsata, and Apis mellifera to the ectoparasitic mite, Tropilaelaps mercedesae, were compared using two laboratory bioassays: cohorts of 50 caged worker bees and individual-caged worker bees, all of unknown ages. For the group bioassays, ten T. mercedesae were placed on the bodies of bees in each cohort. After 6 h, nearly 2/3 of the mites placed on A. cerana had fallen from the bees onto sticky traps that were placed under the cages, compared to only about 1/3 for A. dorsata and A. mellifera. The majority of fallen mites fell within 24 h from A. cerana (93.3 ± 2.3%), 36 h from A. dorsata (92.2 ± 1.9%), and 48 h from A. mellifera (91.3 ± 1.4%). Higher proportions of injured mites were observed among the mites that fell from A. cerana (38.3 ± 12.9%) and A. dorsata (33.9 ± 17.4%) than among those that fell from A. mellifera (19.5 ± 7.2%). The rapid fall of mites from the bodies of A. cerana may be due to a combination of auto-grooming and rapid body shaking of the bees. In individual bee assays, where individual bees were challenged with one female T. mercedesae, A. cerana and A. dorsata exhibited faster behavioral responses to the presence of mites than did A. mellifera (39.4 ± 13.2, 44.9 ± 19.2, and 188.4 ± 63.9 s, respectively). Phoretic T. mercedesae were mostly observed attaching to the propodeum/petiole region of all three bee species, although some mites also occupied the wing base area of A. dorsata and A. mellifera.Keywords: Apis mellifera, Apis cerana, grooming behavior, Tropilaelaps mercedesae, Apis dorsataKeywords: Apis mellifera, Apis cerana, grooming behavior, Tropilaelaps mercedesae, Apis dorsat

Bosonic and fermionic transport phenomena of ultracold atoms in one-dimensional optical lattices

Using the microcanonical picture of transport-a framework ideally suited to describe the dynamics of closed quantum systems such as ultracold atom experiments-we show that the exact dynamics of noninteracting fermions and bosons exhibits very different transport properties when the system is set out of equilibrium by removing the particles from half of the lattice. We find that fermions rapidly develop a finite quasisteady-state current reminiscent of electronic transport in nanoscale systems. This result is robust-it occurs with or without a harmonic confining potential and at zero or finite temperature. The zero-temperature bosonic current instead exhibits strong oscillatory behavior that decays into a steady-state of zero current only in the thermodynamic limit. These differences appear most strikingly in the different particle number fluctuations on half of the lattice as a consequence of the spin statistics. These predictions can be readily verified experimentally.Keywords: Gas, Systems, Quantum, Mott insulato

Designing dairy free stalls

Stalls must be large enough to provide a comfortable bed and ad- equate room for cows to rise. As animals get larger, so must the free stalls.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo