Activity budget and spatial distribution of Bennett's wallabies (Macropus rufogriseus) in open versus closed exhibit designs

Although many studies investigating the impacts of zoo exhibit designs on captive animals exist, none have been performed on how they influence the behavior and welfare of captive Bennett's wallabies (Macropus rufogriseus). Here, we assess the impact of exhibit design on the activity budget and spatial distribution of Bennett's wallabies. We compared animal behavior in two open exhibits (i.e. physical interaction between animals and visitors permitted) to two closed exhibits (i.e. physical interaction between animals and visitors prohibited). Behavioral data were collected using focal sampling, and spatial distribution was recorded on exhibit maps at regular time intervals. We found a significant increase in feeding and interactive behaviors in closed exhibits in comparison to open exhibits. However, other behaviors such as resting, locomotion, and vigilance did not vary with design. Functional use of space was similar between both designs; however, the effect of habituation may be relevant to consider in future studies. Although some support for visitor effects were present, our study provided no evidence for strong impacts of exhibit design on Bennett's wallaby welfare. Our study emphasizes the need for additional research into the impacts of how zoo environments affect Bennett's wallaby behavior and welfare.     

Involvement of the activation loop of ERK in the detachment from cytosolic anchoring

The Extracellular signal-regulated kinases (ERKs) are translocated into the nucleus in response to mitogenic stimulation. The mechanism of translocation and the residues in ERKs that govern this process are not clear as yet. Here we studied the involvement of residues in the activation loop of ERK2 in determining its subcellular localization. Substitution of residues in the activation loop to alanines indicated that residues 173-181 do not play a significant role in the phosphorylation and activation of ERK2. However, residues 176-181 are responsible for the detachment of ERK2 from MEK1 upon mitogenic stimulation. This dissociation can be mimicked by substitution of residues 176-178 to alanines and is prevented by deletion of these residues or by substitution of residues 179-181 to alanines. On the other hand, residues 176-181, as well as residues essential for ERK2 dimerization, do not play a role in the shuttle of ERK2 through nuclear pores. Thus, phosphorylation-induced conformational rearrangement of residues in the activation loop of ERK2 plays a major role in the control of subcellular localization of this protein.     

Biochemical characterization of a phosphinate inhibitor of Escherichia coli MurC

The bacterial UDP-N-acetylmuramyl-L-alanine ligase (MurC) from Escherichia coli, an essential, cytoplasmic peptidoglycan biosynthetic enzyme, catalyzes the ATP-dependent ligation of L-alanine (Ala) and UDP-N-acetylmuramic acid (UNAM) to form UDP-N-acetylmuramyl-L-alanine (UNAM-Ala). The phosphinate inhibitor 1 was designed and prepared as a multisubstrate/transition state analogue. The compound exhibits mixed-type inhibition with respect to all three enzyme substrates (ATP, UNAM, Ala), suggesting that this compound forms dead-end complexes with multiple enzyme states. Results from isothermal titration calorimetry (ITC) studies supported these findings as exothermic binding was observed under conditions with free enzyme (K(d) = 1.80-2.79 microM, 95% CI), enzyme saturated with ATP (K(d) = 0.097-0.108 microM, 95% CI), and enzyme saturated with the reaction product ADP (K(d) = 0.371-0.751 microM, 95% CI). Titrations run under conditions of saturating UNAM or the product UNAM-Ala did not show heat effects consistent with competitive compound binding to the active site. The potent binding affinity observed in the presence of ATP is consistent with the inhibitor design and the proposed Ordered Ter-Ter mechanism for this enzyme; however, the additional binding pathways suggest that the inhibitor can also serve as a product analogue.     

LAT is required for tyrosine phosphorylation of phospholipase cgamma2 and platelet activation by the collagen receptor GPVI

In the present study, we have addressed the role of the linker for activation of T cells (LAT) in the regulation of phospholipase Cgamma2 (PLCgamma2) by the platelet collagen receptor glycoprotein VI (GPVI). LAT is tyrosine phosphorylated in human platelets heavily in response to collagen, collagen-related peptide (CRP), and FcgammaRIIA cross-linking but only weakly in response to the G-protein-receptor-coupled agonist thrombin. LAT tyrosine phosphorylation is abolished in CRP-stimulated Syk-deficient mouse platelets, whereas it is not altered in SLP-76-deficient mice or Btk-deficient X-linked agammaglobulinemia (XLA) human platelets. Using mice engineered to lack the adapter LAT, we showed that tyrosine phosphorylation of Syk and Btk in response to CRP was maintained in LAT-deficient platelets whereas phosphorylation of SLP-76 was slightly impaired. In contrast, tyrosine phosphorylation of PLCgamma2 was substantially reduced in LAT-deficient platelets but was not completely inhibited. The reduction in phosphorylation of PLCgamma2 was associated with marked inhibition of formation of phosphatidic acid, a metabolite of 1,2-diacylglycerol, phosphorylation of pleckstrin, a substrate of protein kinase C, and expression of P-selectin in response to CRP, whereas these parameters were not altered in response to thrombin. Activation of the fibrinogen receptor integrin alpha(IIb)beta(3) in response to CRP was also reduced in LAT-deficient platelets but was not completely inhibited. These results demonstrate that LAT tyrosine phosphorylation occurs downstream of Syk and is independent of the adapter SLP-76, and they establish a major role for LAT in the phosphorylation and activation of PLCgamma2, leading to downstream responses such as alpha-granule secretion and activation of integrin alpha(IIb)beta(3). The results further demonstrate that the major pathway of tyrosine phosphorylation of SLP-76 is independent of LAT and that there is a minor, LAT-independent pathway of tyrosine phosphorylation of PLCgamma2. We propose a model in which LAT and SLP-76 are required for PLCgamma2 phosphorylation but are regulated through independent pathways downstream of Syk.     

An extinct genus of Salicaceae based on twigs with attached flowers, fruits, and foliage from the Eocene Green River Formation of Utah and Colorado, USA

A newly recovered twig with attached leaves and flowers from the Eocene Green River Formation of Utah provides the basis for recognizing a new, extinct genus of Salicaceae sensu lato (s.l.). Pseudosalix handleyi gen. et sp. nov. has alternate lanceolate leaves with pinnate, semicraspedodromous venation and a serrate margin with glandular teeth. The inflorescence is terminal on the twig and is unisexual, composed of flowers organized in a paniculoid cyme, with lateral paraclades of pedicellate flowers. The attached pistillate flowers have four prominent sepals that are valvate in bud, spreading but basally fused at anthesis; the single pistil of each flower is ovoid with three or four longitudinal sutures, indicating development to a capsular fruit. Three or four recurved styles radiate from the apex of the pistil, each with a distal globose stigma. The infructescence, verified by attachment to twigs with the same kind of leaves, bore capsular fruits of three and four valves. Associated but unattached, staminate flowers also have four well-developed, basally connate sepals. They are pedicellate and bear several stamens, each with a short filament and globose anther. The available morphological characters place the fossil species within the Salicaceae s.l. as an immediate sister to the clade containing Populus and Salix. Although the likely outgroup genera (including Itoa, Poliothyrsis, Carrierea, and Idesia) to tribe Saliceae all occur in Asia today and not North America, the occurrence of both Pseudosalix and Populus in the Eocene of Utah raises the possibility of a North American origin for the Saliceae.     

alpha(1)-Adrenoceptor agonists: the identification of novel alpha(1A )subtype selective 2'-heteroaryl-2-(phenoxymethyl)imidazolines

Novel 2'-heteroaryl-2-(phenoxymethyl)imidazolines have been identified as potent agonists of the cloned human alpha(1)-adrenoceptors in vitro. The nature of the 2'-heteroaryl group can have significant effects on the potency, efficacy, and subtype selectivity in this series. alpha(1A) Subtype selective agonists have been identified.     

A human novel gene DERPC on 16q22.1 inhibits prostate tumor cell growth and its expression is decreased in prostate and renal tumors

BACKGROUND: Deletion of chromosome 16q is frequently associated with diverse tumors. Numerous studies strongly suggest the presence of one or more tumor suppressor genes on chromosome 16q22 to 16qter including the widely studied cadherin gene family. However, the specific tumor suppressor genes residing in this region need better definition and characterization. MATERIAL AND METHODS: Standard molecular biology approaches have been used to clone and characterize the DERPC cDNA and its protein product on chromosome 16q22.1. Northern blotting was used to define the expression pattern in a multiple human tissue blots. DERPC expression was examined in multi-tumor array (Clontech, CA, USA) dot blot as well as in laser capture microdissection (LCM) derived prostate cancer (CaP) specimens by quantitative RT-PCR. Western blot analysis and a fluorescent microscopy were used to characterize the molecular size and the cellular location of green fluorescent protein (GFP)-tagged DERPC fusion proteins. A colony formation assay was conducted to determine the effects of DERPC expression on tumor cell growth. RESULTS: A novel gene DERPC (Decreased Expression in Renal and Prostate Cancer) was identified and characterized. DERPC encoded a strong basic, proline- and glycine-rich nuclear protein. DERPC was ubiquitously expressed, with abundant expression in kidney, skeletal muscle, testis, liver, ovary, and heart and moderate expression in prostate. DERPC expression was reduced in renal (67%) and prostate tumors (33%). Expression of DERPC has inhibitory potential on CaP cell growth. Further, overexpression of DERPC in LNCaP cells caused alterations of nuclear morphology. CONCLUSION: This study suggests that decreased expression of DERPC may be implicated in tumorigenesis of renal and CaPs.     

Functional association between SLAP-130 and SLP-76 in Jurkat T cells

T cell antigen receptor (TCR) engagement results in protein-tyrosine kinase activation which initiates signaling cascades leading to induction of the interleukin-2 gene. Previous studies identified two substrates of the TCR-induced protein-tyrosine kinases, SH2 domain-containing leukocyte specific protein of 76 kDa (SLP-76) and SLP-76-associated phosphoprotein of 130 kDa (SLAP-130). While SLP-76 appears to couple the TCR with downstream signals, SLAP-130 may play a negative regulatory role in T cell activation. In this study, we demonstrate that consistent with its ability to abrogate the SLP-76 augmentation of TCR-induced activation of the NFAT/AP1 region of the interleukin-2 promoter, overexpression of SLAP-130 also interferes with the rescue of signaling in SLP-76-deficient Jurkat cells in co-transfection experiments. The effect of SLAP-130 on SLP-76 function is specific for regulating TCR-induced ERK activation, but not phospholipase Cgamma 1 phosphorylation. By generating both deletion and point mutants of SLAP-130, we identified tyrosine 559 as critical for the interaction between SLP-76 and SLAP-130. We show that mutation of this residue in context of full-length SLAP-130 diminishes the ability of SLAP-130 to abrogate SLP-76 function. These data suggest that the SLAP-130/SLP-76 association is important for the negative regulatory role that SLAP-130 appears to play in T cell signaling.