The role of the cysteine-rich region of the β2 integrin subunit in the leukocyte function-associated antigen-1 (LFA-1, αLβ2, CD11a/CD18) heterodimer formation and ligand binding

The cysteine-rich region (CRR) of the β2 integrin subunit was replaced by that of β1 to give the chimera β2NV1. β2NV1 can combine with αL to form a variant leukocyte-function-associated antigen (LFA)-1 on COS cell surface, suggesting that the specificity of the β2 interaction with αL does not lie in the CRR. Unlike those expressing wild-type LFA-1, COS cells expressing αLβ2NV1 are constitutively active in intercellular adhesion molecule (ICAM)-1 adhesion. These results suggest that activation of LFA-1 involves the release of an intramolecular constraint, which is maintained, in part, by the authentic β2 CRR.     

Structure of Haze Forming Proteins in White Wines: Vitis vinifera Thaumatin-Like Proteins

Grape thaumatin-like proteins (TLPs) play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1), and having different unfolding temperatures (56 vs. 62°C), with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions.     

Polyphyly of Asian Tree Toads,Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia

The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species’ are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species.     

On the mechanism by which dopamine inhibits prolactin release in the anterior pituitary

An $\text{in}$$\text{vitro}$ perfusion system was used to assess the effects of chloride channel blockers, dopamine (DA) receptor agonists and antagonists, and GABA receptor agonists and antagonists on prolactin release from the mouse anterior pituitary. Dopamine and muscimol inhibited prolactin release ($\text{IC}{}_{50}{}^1\text{= 6 × 10}{}^{\mathrm{?8}}\text{M and}\text{10}{}^{\mathrm{?5}}\text{M}$ respectively). The GABA receptor antagonist bicuculline blocked the inhibition of prolactin release by muscimol but not dopamine. The dopamine receptor antagonist chlorpromazine blocked the dopamine- but not muscimol-induced inhibition of prolactin release. Haloperidol, however, reversed both the muscimol and dopamine induced inhibition of prolactin release. Furthermore, the chloride channel blocker picrotoxinin blocked the inhibition of prolactin release elicited by both dopamine and muscimol. These later results suggest that the anterior pituitary dopamine receptor which mediates the inhibition of prolactin release may be coupled to a picrotoxinin sensitive chloride ionophore and that haloperidol may affect the function of both DA and GABA receptors in the anterior pituitary.     

Phencyclidine-induced depressions of cerebellar purkinje neurons

Local administration of phencyclidine (PCP) by pressure ejection elicited a dose-dependent slowing of the spontaneous discharge of cerebellar Purkinje neurons. Ketamine also depressed firing and was much less potent than PCP. Effects of both PCP and ketamine were antagonized by local or parenteral administration of antipsychotic drugs. The similarities between the electrophysiological and behavioral actions of phencyclidine suggest that alterations in neuronal discharge may underlie its psychotomimetic properties.