Virus-transformed pre-B cells show ordered activation but not inactivation of immunoglobulin gene rearrangement and transcription

Virus-transformed pre-B cells undergo ordered immunoglobulin (Ig) gene rearrangements during culture. We devised a series of highly sensitive polymerase chain reaction assays for Ig gene rearrangement and unrearranged Ig gene segment transcription to study both the possible relationship between these processes in cultured pre-B cells and the role played by heavy (H) chain (mu) protein in regulating gene rearrangement. Our analysis of pre-B cell cultures representing various stages of maturity revealed that transcription of each germline Ig locus precedes or is coincident with its rearrangement. Cell lines containing one functional rearranged H chain allele, however, continue to transcribe and to rearrange the allelic, unrearranged H chain locus. These cell lines appear to initiate but not terminate rearrangement events and therefore provide information about the requirements for activating rearrangement but not about allelic exclusion mechanisms

The Influence of Supplemental Feeding on the Movement Patterns of the Southern Stingray, Dasyatis americana, at Grand Cayman, Cayman Islands

There are currently over 300 sites in nearly 40 countries where a variety of marine animals are provided supplemental food by humans. The influence of this supplemental feeding on the behavior, physiology, growth, reproduction and movements of the animals involved is seldom known. Intentional supplemental feeding of the southern stingray, Dasyatis americana, has occurred at Stingray City (SC) and Stingray City Sandbar (SCS) at Grand Cayman since 1986. There are no specific regulations governing the feeding of D. americana at Grand Cayman, and neither the species nor the feeding sites are afforded any official protective status. This study investigated how supplemental feeding influences the movement patterns of D. americana at Grand Cayman, including activity spaces, rates of movement, site fidelity and diel patterns. This research is the first detailed investigation into the influence of supplemental feeding on the movement patterns of a marine animal. The objectives of this study were to investigate and compare the movement patterns of D. americana at supplemental feeding sites and non-feeding ‘wild’ control sites. Passive Integrative Transponder (PIT) tags were implanted in 327 stingrays, 183 of which were recaptured; 100% of recaptured stingrays retained their tags over the duration of the study, based on tissue sample scarring. External tags were attached to 35 stingrays. Tagging data indicate that a spatially isolated community of approximately 160 D. americana utilize SCS. Seven wild and seven provisioned stingrays were tracked manually from five to 72 h, and five mature females at SCS were tracked automatically using an array of two bottom monitors. Provisioned female stingrays at SCS utilized significantly smaller 24 h activity spaces (0.132±0.079 km2) than wild female stingrays (0.876±0.171km2). Both groups utilized significantly larger activity spaces at night than during the day. However, there was a marked difference in the diel activity levels between provisioned and wild stingrays: provisioned stingrays were active over a small area during daytime supplemental feeding, whereas wild stingrays were more active and foraged during the night (nocturnal). Average rates of movement did not significantly differ between the two groups. Tidal phase had no effect on activity space size or rate of movement for either group. The core areas of provisioned stingrays showed significantly more overlap than those of wild stingrays, indicating that supplemental feeding has disrupted the spatial distribution of the community at SCS and increased the local density of D. americana to atypical levels. Provisioned female stingrays consistently frequented SCS during periods of supplemental feeding and exhibited long term (at least up to one year) site fidelity to this site. These findings suggest that provisioned stingrays are highly conditioned to the supplemental food resources provided at SCS. Provisioned stingrays exhibited optimal foraging and have reduced and centralized their core areas and activity spaces at SCS in order to maximize their accrual of food resources. The availability of food resources is a significant factor regulating the size and location of core areas and activity spaces, population density and the diel activities (i.e. the spatial and temporal distribution) of D. americana at Grand Cayman

The promoter of the human interleukin-2 gene contains two octamer-binding sites and is partially activated by the expression of Oct-2

The gene encoding interleukin-2 (IL-2) contains a sequence 52 to 326 nucleotides upstream of its transcriptional initiation site that promotes transcription in T cells that have been activated by costimulation with tetradecanoyl phorbol myristyl acetate (TPA) and phytohemagglutinin (PHA). We found that the ubiquitous transcription factor, Oct-1, bound to two previously identified motifs within the human IL-2 enhancer, centered at nucleotides -74 and -251. Each site in the IL-2 enhancer that bound Oct-1 in vitro was also required to achieve a maximal transcriptional response to TPA plus PHA in vivo. Point mutations within either the proximal or distal octamer sequences reduced the response of the enhancer to activation by 54 and 34%, respectively. Because the murine T-cell line EL4 constitutively expresses Oct-2 and requires only TPA to induce transcription of the IL-2 gene, the effect of Oct-2 expression on activation of the IL-2 promoter in Jurkat T cells was determined. Expression of Oct-2 potentiated transcription 13-fold in response to TPA plus PHA and permitted the enhancer to respond to the single stimulus of TPA. Therefore, both the signal requirements and the magnitude of the transcription response of the IL-2 promoter can be modulated by Oct-2

The Effects of Processing and Ripening on the Quality of Pizza Cheese

End of Project ReportThe main aims of this project were to quantify the changes in fuctionality during maturation of cheese and to develop an understanding of the factors which mediate the development of functionality. The approach to achieving these objectives involved the establishment of a suitable pilot plant production procedure for low moisture Mozzarella, developing and/or adapting existing methods for objective evaluation of the functional properties of pizza cheeses, and evaluating the effects of ripening and variations in cheesemaking conditions (e.g. pH at stretching) on the composition, yield and functionality of low moisture Mozzarella cheese. The main conclusions were as follows: The technology for developing low moisture Mozzarella cheeses, with different compositions and functionalities, via alteration of cheesemaking parameters, has been developed. A database has been established on the storage-related changes that occur in texture, proteolysis and functionality of low moisture Mozzarella cheeses of different compositions. In addition an extensive database on the compositional, biochemical, microstructural, rheological and/or functional properties of different commerical cheeses - low moisture Mozzarella, Cheddar and analogue pizza cheese, has been compiled. The functionality of low moisture Mozzarella changes markedly on storage/ripening at 4ºC. Initially, during the first 5-10 days of storage, the functionality of the baked cheese is poor but then improves on further storage as reflected by reductions in melt time and apparent viscosity (chewiness) and increases in stretchability and flowability. The changes in functionality are mediated by storage-related increases in pH, proteolysis, protein-bound water and free oil in the cheese. On prolonged storage (e.g. > 60 d at 4ºC), the cheese functionality becomes impaired as the shredded cheese develops an increased susceptibility to clumping/balling which makes it difficult to dispense the cheese onto the pizza pie and achieve a uniform surface distribution. Moreover, the baked cheese tends to exude excess free oil and loses its desired level of chewiness attaining a 'soupy' consistency. Novel methods were developed/adapted to objectively quantify functionality in the raw (susceptibility of shredded cheese to clump) and cooked (stretchability, chewiness, viscoelasticity) cheeses.Department of Agriculture, Food and the Marin

Timely, Relevant, Practical: A Study of Writing Center Summer Institute Alumni Perceptions of Value and Benefits

Since its inception in 2003, the IWCA Summer Institute (SI) has been understood within the writing center field to be an important professional development opportunity for new and experienced writing center professionals (WCPs). Publications on the SI to date have focused on anecdotal perceptions of the benefits to leaders and participants or on a single outcome, such as research output. Thus, the writing center field knows little about how and in what ways participants perceive the SI’s benefits across cohorts and across a variety of professional areas. By gathering quantitative and qualitative data from every SI cohort from 2003 to 2019, the goal of this study was to identify and define the benefits of the SI, focusing in particular on how participants themselves understand them. The survey received 161 responses, a response rate of approximately 27%; all 17 years of the SI were represented. The study found that, despite the field’s shifting priorities since 2003, the concerns and needs of WCPs have remained relatively constant over time, and that the SI serves the most pressing administrative needs of participants

Functional immunoglobulin transgenes guide ordered B-cell differentiation in Rag-1-deficient mice

We have examined the regulatory role of the individual components of the immunoglobulin antigen receptor in B-cell development by transgenic complementation of Rag-1 deficient (Rag-1⁻) mice. Complementation with a membrane µ heavy chain (µHC) gene allows progression of developmentally arrested Rag-1⁻ pro-B-cells to the small pre-B cell stage, whereas the introduction of independently integrated µHC and κ light chain (κLC) transgenes promotes the appearance of peripheral lymphocytes which, however, remain unresponsive to external stimuli. Complete reconstitution of the B-cell lineage and the emergence of functionally nature Rag-1⁻ peripheral B cells is achieved by the introduction of cointegrated heavy and light chain transgenes encoding an anti-H-2^k antibody. This experimental system demonstrates the competence of the µHC and κLC to direct and regulate the sequential stages of B-cell differentiation, defines the time at which negative selection of self-reactive B cells occurs, and shows that elimination of these cells occurs equally well in the absence of Rag-1 as in its presence. These data also support the hypothesis that Rag-1 directly participates in the V(D)J recombination process

Bcl-2 Can Rescue T Lymphocyte Development in Interleukin-7 Receptor–Deficient Mice but Not in Mutant rag-1−/− Mice

AbstractSignals from cytokine and antigen receptors play crucial roles during lymphocyte development. Mice lacking interleukin-7 receptor are lymphopenic, due to a defect in cell expansion at an early stage of differentiation, and the few mature T cells that develop in IL-7R−/− animals are functionally impaired. Both defects were rescued completely by overexpression of the anti- apoptosis protein Bcl-2. T cell progenitors lacking antigen receptor molecules are also blocked in differentiation and die, presumably because they fail to receive a positive signal via their pre-T cell receptor. Surprisingly, Bcl-2 did not promote survival or differentiation of T cells in rag-1−/− mice. These results provide evidence that blocking apoptosis is the essential function of IL-7R during differentiation and activation of T lymphocytes and that pre-TCR signaling blocks a pathway to apoptosis that is insensitive to Bcl-2

Biochemical and Functional Relationships in Cheese.

End of Project ReportCheese is used extensively in cooking applications, mainly because of its flavour and heat-induced functionality, which is a composite of different attributes such as softening, flow and stretch. The functional attributes of cooked cheese generally have a major impact on the quality of foods in which cheese is included as an ingredient, e.g. pizza pie. Owing to its importance in cookery applications, numerous studies have been undertaken on the effects of different factors on the age-related changes in the functionality of cooked cheese, especially Mozzarella, and to a lesser extent, Cheddar and processed cheese. These studies have shown that the functionality of natural cheese is dynamic, with the different functional attributes undergoing marked changes during ripening, and, for a given cheese variety, the desired functional attributes are optimum within a specific time frame during maturation. The time at which the cheese becomes functional and the width of the window - and hence the functional shelf-life, are affected by the extent of chemical changes, including the increase in proteolysis and the ratio of bound to free moisture. The main aims of this project were to investigate the effects of the following on the age-related changes in heat-related functional attributes (e.g. stretchability, fluidity) of cheese: * fat reduction, * the degree of fat emulsification, * the pH and calcium content and their interaction, * the correlation between proteolysis and functional attributes, especially attributes other than flowability, e.g. rheological properties of raw cheese, stretchability of heated cheese, and * the age-related changes in the functionality of cheeses other than Mozzarella, e.g. analogue pizza cheese and Emmental. At the outset of this project, comparatively little information was available on the effects of the above parameters on the age-related changes in heatinduced functional attributes (e.g. stretchability, fluidity) of cheese, especially for varieties other than Mozzarella.Department of Agriculture, Food and the Marin

Supplemental Feeding for Ecotourism Reverses Diel Activity and Alters Movement Patterns and Spatial Distribution of the Southern Stingray, Dasyatis americana

Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world’s most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (