Dual-function regulators: the cAMP receptor protein and the CytR regulator can act either to repress or to activate transcription depending on the context.

Studies of gene regulation have revealed that several transcriptional regulators can switch between activator and repressor depending upon both the promoter and the cellular context. A relatively simple prokaryotic example is illustrated by the Escherichia coli CytR regulon. In this system, the cAMP receptor protein (CRP) assists the binding of RNA polymerase as well as a specific negative regulator, CytR. Thus, CRP functions either as an activator or as a corepressor. Here we show that, depending on promoter architecture, the CRP/CytR nucleoprotein complex has opposite effects on transcription. When acting from a site close to the DNA target for RNA polymerase, CytR interacts with CRP to repress transcription, whereas an interaction with CRP from appropriately positioned upstream binding sites can result in formation of a huge preinitiation complex and transcriptional activation. Based on recent results about CRP-mediated regulation of transcription initiation and the finding that CRP possesses discrete surface-exposed patches for protein-protein interaction with RNA polymerase and CytR, a molecular model for this dual regulation is discussed.

Mismatch repair in Xenopus egg extracts: DNA strand breaks act as signals rather than excision points.

In Xenopus egg extracts, DNA strand breaks (nicks) located 3' or 5' to a mismatch cause an overall 3-fold stimulation of the repair of the mismatch in circular heteroduplex DNA molecules. The increase in mismatch repair is almost entirely due to an increase in repair of the nicked strand, which is stimulated 5-fold. Repair synthesis is centered to the mismatch site, decreases symmetrically on both sides, and its position is not significantly altered by the presence of the nick. Therefore, it appears that in the Xenopus germ cells, the mismatch repair system utilizes nicks as signals for the induction and direction of mismatch repair, but not as the start or end point for excision and resynthesis.

The transcription factors c-myb and GATA-2 act independently in the regulation of normal hematopoiesis.

The transcription factors c-myb and GATA-2 are both required for blood cell development in vivo and in vitro. However, very little is known on their mechanism(s) of action and whether they impact on complementary or overlapping pathways of hematopoietic proliferation and differentiation. We report here that embryonic stem (ES) cells transfected with c-myb or GATA-2 cDNAs, individually or in combination, underwent hematopoietic commitment and differentiation in the absence of added hematopoietic growth factors but that stimulation with c-kit and flt-3 ligands enhanced colony formation only in the c-myb transfectants. This enhancement correlated with c-kit and flt-3 surface receptor up-regulation in c-myb-(but not GATA-2-) transfected ES cells. Transfection of ES cells with either a c-myb or a GATA-2 antisense construct abrogated erythromyeloid colony-forming ability in methyl cellulose; however, introduction of a full-length GATA-2 or c-myb cDNA, respectively, rescued the hematopoiesis-deficient phenotype, although only c-myb-rescued ES cells expressed c-kit and flt-3 surface receptors and formed increased numbers of hematopoietic colonies upon stimulation with the cognate ligands. These results are in agreement with previous studies indicating a fundamental role of c-myb and GATA-2 in hematopoiesis. Of greater importance, our studies suggest that GATA-2 and c-myb exert their roles in hematopoietic gene regulation through distinct mechanisms of action in nonoverlapping pathways.

The cell wall components peptidoglycan and lipoteichoic acid from Staphylococcus aureus act in synergy to cause shock and multiple organ failure.

Although the incidence of Gram-positive sepsis has risen strongly, it is unclear how Gram-positive organisms (without endotoxin) initiate septic shock. We investigated whether two cell wall components from Staphylococcus aureus, peptidoglycan (PepG) and lipoteichoic acid (LTA), can induce the inflammatory response and multiple organ dysfunction syndrome (MODS) associated with septic shock caused by Gram-positive organisms. In cultured macrophages, LTA (10 micrograms/ml), but not PepG (100 micrograms/ml), induces the release of nitric oxide measured as nitrite. PepG, however, caused a 4-fold increase in the production of nitrite elicited by LTA. Furthermore, PepG antibodies inhibited the release of nitrite elicited by killed S. aureus. Administration of both PepG (10 mg/kg; i.v.) and LTA (3 mg/kg; i.v.) in anesthetized rats resulted in the release of tumor necrosis factor alpha and interferon gamma and MODS, as indicated by a decrease in arterial oxygen pressure (lung) and an increase in plasma concentrations of bilirubin and alanine aminotransferase (liver), creatinine and urea (kidney), lipase (pancreas), and creatine kinase (heart or skeletal muscle). There was also the expression of inducible nitric oxide synthase in these organs, circulatory failure, and 50% mortality. These effects were not observed after administration of PepG or LTA alone. Even a high dose of LTA (10 mg/kg) causes only circulatory failure but no MODS. Thus, our results demonstrate that the two bacterial wall components, PepG and LTA, work together to cause systemic inflammation and multiple systems failure associated with Gram-positive organisms.

5-Methyl-2'-deoxycytidine in single-stranded DNA can act in cis to signal de novo DNA methylation.

Methylation of cytosine residues in DNA plays an important role in regulating gene expression during vertebrate embryonic development. Conversely, disruption of normal patterns of methylation is common in tumors and occurs early in progression of some human cancers. In vertebrates, it appears that the same DNA methyltransferase maintains preexisting patterns of methylation during DNA replication and carries out de novo methylation to create new methylation patterns. There are several indications that inherent signals in DNA structure can act in vivo to initiate or block de novo methylation in adjacent DNA regions. To identify sequences capable of enhancing de novo methylation of DNA in vitro, we designed a series of oligodeoxyribonucleotide substrates with substrate cytosine residues in different sequence contexts. We obtained evidence that some 5-methylcytosine residues in these single-stranded DNAs can stimulate de novo methylation of adjacent sites by murine DNA 5-cytosine methyltransferase as effectively as 5-methylcytosine residues in double-stranded DNA stimulate maintenance methylation. This suggests that double-stranded DNA may not be the primary natural substrate for de novo methylation and that looped single-stranded structures formed during the normal course of DNA replication or repair serve as "nucleation" sites for de novo methylation of adjacent DNA regions.

Prolactin-immunoglobulin G complexes from human serum act as costimulatory ligands causing proliferation of malignant B lymphocytes.

Several lines of evidence indicate that immunoglobulin-bound prolactin found in human serum is not a conventional complex between an anti-prolactin antibody and prolactin but a different type of association of prolactin with the Fab portion of IgG heavy chains. The complex of prolactin with IgG was purified from serum by anti-human prolactin affinity chromatography and was shown to contain close to 1 mole of N epsilon-(gamma-glutamyl)lysine crosslinks per mole of complex, a characteristic feature in structures crosslinked by transglutaminase. Interestingly, the complex caused a proliferation of cells from a subset of patients with chronic lymphocytic leukemia, while it was inactive in a cell proliferation prolactin bioassay. By contrast, human prolactin stimulated the proliferation of cells in the bioassay but had no effect on the complex-responsive cells from the patients. Competition studies with prolactin and free Fc fragment of IgG demonstrated a necessity for engaging both the prolactin and the immunoglobulin receptors for proliferation. More importantly, competition for the growth response by free prolactin and IgG suggests both possible reasons for the slow growth of this neoplasm as well as avenues for control of the disease.

Caught in the act: gas and stellar velocity dispersions in a fast Quenching compact star-forming galaxy at z ~ 1.7

We present Keck I MOSFIRE spectroscopy in the Y and H bands of GDN-8231, a massive, compact, star-forming galaxy at a redshift of z ~ 1.7. Its spectrum reveals both Hα and [Nii] emission lines and strong Balmer absorption lines. The Hα and Spitzer MIPS 24 μm fluxes are both weak, thus indicating a low star-formation rate of SFR≲5-10 M_⨀ yr−1. This, added to a relatively young age of ~700 Myr measured from the absorption lines, provides the first direct evidence for a distant galaxy being caught in the act of rapidly shutting down its star formation. Such quenching allows GDN-8231 to become a compact, quiescent galaxy, similar to three other galaxies in our sample, by z ~ 1.5. Moreover, the color profile of GDN-8231 shows a bluer center, consistent with the predictions of recent simulations for an early phase of inside-out quenching. Its line-of-sight velocity dispersion for the gas, σ_LOG^gas = 127 ± 32 km s^−1, is nearly 40% smaller than that of its stars, σ_LOG^* = 215 ± 35 km s^−1. High-resolution hydro-simulations of galaxies explain such apparently colder gas kinematics of up to a factor of ~1.5 with rotating disks being viewed at different inclinations and/or centrally concentrated star-forming regions. A clear prediction is that their compact, quiescent descendants preserve some remnant rotation from their star-forming progenitors.

U.S.-Taiwan Relations: A Study on the Taiwan Relations Act

The relationship between the United States and Taiwan is of great importance to both parties. Taiwan offers certain strategic opportunities for the promotion of American national security interests, and the U.S. accordingly provides Taiwan with support of both a defensive and diplomatic nature. The official U.S. policies regarding relations with Taiwan are enumerated in the Taiwan Relations Act (United States Code Title 22 Chapter 48 Sections 3301 - 3316). The act, approved by the U.S. Congress in 1967, stipulates the terms of the bilateral relationship with regard to national defense and diplomatic relations among other factors. This paper seeks to obtain a more developed picture of sentiments on both sides of this relationship in order to understand better the U.S.'s influence and power in Taiwan and in the region.

A Framework for Addressing Psychological Inflexibility Among Act Therapists-In-Training.

Novice therapists training in Acceptance and Commitment Therapy (ACT) may encounter challenges in therapy in which their own personal history functions as a barrier to flexible modes of therapeutic engagement with the therapist. From the ACT perspective, counter-therapeutic interpersonal responses may be examined relative to six behavioral sub-processes. It is suggested that the most vulnerable moments for the therapist will involve those in which certain contextual features of therapy pull historical awareness of a painful personal past into relation with the psychological present. This paper hypothesizes that utilizing approaches based in ACT will assist therapists in overcoming these challenges and will illustrate how to approach case formulation and intervention with therapists in training from a functional contextualistic perspective. To begin, the philosophical and theoretical underpinnings of ACT will be outlined in sufficient depth to intellectually ground the model and its therapeutic project. This conceptual foundation will then be brought to applied focus using hypothetical case material, followed by ACT interventions designed to increase clinical flexibility in the given therapeutic scenario. Future research that systematically examines the effectiveness of such methods among therapists is encouraged.

A Review of the Petition Process for the Endangered Species Act

The Endangered Species Act of 1973 (ESA) is an exceptionally powerful law which requires the involvement of many stake holders, including government and non-government professionals. This project reviewed the requirements of the ESA and the expectations of the USFWS and referenced them to the actions taken by the petitioner in the preparation of the petition for the black-tailed prairie dog. The study has shown the knowledge required by the petitioner to submit an effective petition and also the importance of communicating this knowledge so that the federal agencies may make sound decisions when deciding to protect a species and its habitat. This research can be used as a preliminary reference for beginning the process for future petitions.

Analysis of the Convention on International Trade in Endangered Species (CITES) and the Endangered Species Act (ESA) and Its Effects on Giant Panda Conservation

The giant panda, Ailuropoda melanoleuca is an endangered species that is protected under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Endangered Species Act (ESA). Numerous factors have led to a decline in giant panda populations in China including habitat loss from human activity, poaching, panda inbreeding and a low reproductive rate. This capstone analyzes the effects of CITES and ESA as policies for the protection of panda populations and their habitat. CITES and ESA provide some protection for panda populations in the United States. However, these policies do not address panda habitat protection in China.

The Effect of the Farmer Assurance Provision of the Consolidated and Continuing Appropriations Act, 2013 on Biodiversity and Global Food Security

A rider to a US law, the Consolidated and Continuing Appropriations Act, 2013, known as the Farmer Assurance Provision, encourages the large-scale genetic modification and global distribution of agricultural crops, thereby undermining the Food and Agriculture Organization of the United Nations' determination that food security rests on biodiversity. The rider blocks the US Department of Agriculture's mandate to prohibit farmers from growing crops from biotechnological seeds where the courts have found that this farm practice may cause damage to human health and/or degrade the environment. Despite genetically modified organisms (GMOs) reducing unwanted traits in plants, the paper supports the UN's mission for biodiversity and that more long-term testing was (and is) needed for GMO products, developed from 1994 on, before a hasty piece of Congressional legislation as was made in this case.

[ Property act], 1787

Copy of act pertaining to taking of property for failure to pay taxes. Signed: Alexander Martin and John Sitgreaves.

An act for granting to His Majesty the sum of fifty-five thousand pounds, and for striking the same in bills of credit, in the manner herein after directed..., 1764

Contains an act for collection of taxes to pay the debt by establishing a set fee of fifteen shillings per head and household.