Two new feather mites of the genus Proctophyllodes (Acari: Proctophyllodidae) from passerines of China (Aves: Passeriformes)

Two new species of the feather mite genus Proctophyllodes (Analgoidea: Proctophyllodidae) are described from two passerine birds (Passeriformes) in China: Proctophyllodes scleroticus sp. nov. from the Brandt's Mountain Finch Leucosticte brandti pallidior (Fringillidae) and P. micrurus sp. nov. from the White-rumped Snow Finch Onychostruthus taczanowskii (Passeridae). Proctophyllodes scleroticus sp. nov. belongs to the tricetratus species-group, and differs from the most similar species P. petroniae Atyeo & Braasch, 1966 by the following characters: in male, the genital sheath is heavily sclerotized, peach shaped, and extending to the level of setae g, anal suckers are surrounded with a pair of membranes, and terminal lamella is relatively greater, and in female, lobar shield is divided into two independent shields by the anal opening and anal opening extends beyond the level of setae ps1, terminal appendage is long. Proctophyllodes micrurus sp. nov. belongs to the musicus species-group, and differs from the most similar species P. saltatoris Atyeo & Braasch, 1966 by the following characters: in male, genital arch and the anterior part of opisthogastric shield are about the same width, anal suckers are surrounded with a pair of membranes, genital organ extends to the anterior 1/3 of the level of setae g and setae ps3, terminal lamella are located closely to each other and slightly greater, and in female, lobar shields are medially divided into two halves, terminal appendages are small, about 1/10 of setae h3, edge of the cleft is almost horizontal.

Two new species of Photonectes with blue luminous tissue on body, and a re-examination of P. mirabilis (Teleostei: Stomiidae)

Two new species of the mesopelagic genus Photonectes are described from the Pacific Ocean. Both of them are characterized by the presence of blue luminous tissue on the body. Photonectes cyanogrammicus new species, is characterized by the unique shape of the mental barbel, expanded distally and lacking bulbs or appendages. It is presently known only from the holotype collected in the Solomon Sea. Photonectes sphaerolampas new species, is described from four specimens collected in the western and central Pacific. It can be easily distinguished from the other species by the presence of the large spherical bulb of the mental barbel with darkly pigmented terminal appendage, split at its tip into several short filaments. Photonectes mirabilis Parr, 1927 is re-described, based on four specimens from the Atlantic and Pacific Oceans; details of jaw dentition and arrangement of the luminous tissue for this species are specified. A key for identification of the species of Photonectes with blue luminous tissue on the body is provided.

Splicing variation of Long-IRBIT determines the target selectivity of IRBIT family proteins

IRBIT [inositol 1,4,5-trisphosphate receptor (IP3R) binding protein released with inositol 1,4,5-trisphosphate (IP3)] is a multifunctional protein that regulates several target molecules such as ion channels, transporters, polyadenylation complex, and kinases. Through its interaction with multiple targets, IRBIT contributes to calcium signaling, electrolyte transport, mRNA processing, cell cycle, and neuronal function. However, the regulatory mechanism of IRBIT binding to particular targets is poorly understood. Long-IRBIT is an IRBIT homolog with high homology to IRBIT, except for a unique N-terminal appendage. Long-IRBIT splice variants have different N-terminal sequences and a common C-terminal region, which is involved in multimerization of IRBIT and Long-IRBIT. In this study, we characterized IRBIT and Long-IRBIT splice variants (IRBIT family). We determined that the IRBIT family exhibits different mRNA expression patterns in various tissues. The IRBIT family formed homo- and heteromultimers. In addition, N-terminal splicing of Long-IRBIT changed the protein stability and selectivity to target molecules. These results suggest that N-terminal diversity of the IRBIT family and various combinations of multimer formation contribute to the functional diversity of the IRBIT family.

Binding Partners for the COOH-Terminal Appendage Domains of the GGAs and γ-Adaptin

The adaptor appendage domains are believed to act as binding platforms for coated vesicle accessory proteins. Using glutathione S-transferase pulldowns from pig brain cytosol, we find three proteins that can bind to the appendage domains of both the AP-1 γ subunit and the GGAs: γ-synergin and two novel proteins, p56 and p200. p56 elicited better antibodies than p200 and was generally more tractable. Although p56 and γ-synergin bind to both GGA and γ appendages in vitro, immunofluorescence labeling of nocodazole-treated cells shows that p56 colocalizes with GGAs on TGN46-positive membranes, whereas γ-synergin colocalizes with AP-1 primarily on a different membrane compartment. Furthermore, in AP-1–deficient cells, p56 remains membrane-associated whereas γ-synergin becomes cytosolic. Thus, p56 and γ-synergin show very strong preferences for GGAs and AP-1, respectively, in vivo. However, the GGA and γ appendages share the same fold as determined by x-ray crystallography, and mutagenesis reveals that the same amino acids contribute to their binding sites. By overexpressing wild-type GGA and γ appendage domains in cells, we can drive p56 and γ-synergin, respectively, into the cytosol, suggesting a possible mechanism for selectively disrupting the two pathways.

Active-site and membrane topology of the DD-peptidase/penicillin-binding protein no. 6 of Enterococcus hirae (Streptococcus faecium) A.T.C.C. 9790

The membrane-bound 43,000-Mr penicillin-binding protein no. 6 (PBP6) of Enterococcus hirae consists of a 30,000-Mr DD-peptidase/penicillin-binding domain and a approximately 130-residue C-terminal appendage. Removal of this appendage by trypsin proteolysis has no marked effect on the catalytic activity and penicillin-binding capacity of the PBP. Anchorage of the PBP in the membrane appears to be mediated by a short 15-20-residue stretch at the C-terminal end of the appendage. The sequence of the 50-residue N-terminal region of the PBP shows high degree of homology with the sequences of the corresponding regions of the PBPs5 of Escherichia coli and Bacillus subtilis. On this basis the active-site serine residue occurs at position 35 in the enterococcal PBP.