The FapF Amyloid Secretion Transporter Possesses an Atypical Asymmetric Coiled Coil

Gram-negative bacteria possess specialized biogenesis machineries that facilitate the export of amyloid subunits, the fibers of which are key components of their biofilm matrix. The secretion of bacterial functional amyloid requires a specialized outer-membrane protein channel through which unfolded amyloid substrates are translocated. We previously reported the crystal structure of the membrane-spanning domain of the amyloid subunit transporter FapF from Pseudomonas. However, the structure of the periplasmic domain, which is essential for amyloid transport, is yet to be determined. Here, we present the crystal structure of the N-terminal periplasmic domain at 1.8-Å resolution. This domain forms a novel asymmetric trimeric coiled coil that possesses a single buried tyrosine residue as well as an extensive hydrogen-bonding network within a glutamine layer. This new structural insight allows us to understand this newly described functional amyloid secretion system in greater detail.     

Is Sperm Ultrastructure Useful in Polychaete Systematics? An Example Using 20 Species of the Fabriciinae (Polychaeta: Sabellidae)

The utility of sperm morphology in the systematics of polychaetes has been questioned in the past. This doubt stems from a problem with methodology, not with sperm morphology. It is argued that sperm characters used in combination with other morphological features have utility at various hierarchical levels. As a test of this proposition males in species from each of the following 10 fabriciin genera: Augeneriella, Fabricia, Fabriciola, Fahricinuda, Manayunkia, Novafabricia, Parafabricia, Pseudofabricia, Pseudofabriciola and an undescribed new Genus A (Fitzhugh et al., in preparation), were examined in order to provide new characters for phylogenetic systematic studies. All species were found to have a dorsal sperm duct running beneath the faecal groove of the thoracic region. No sabellin sabellids or serpulids have this duct. The above Fabriciinae have spermatids developing in large clusters of several hundred cells. Serpulids and sabellins nearly always have sperm developing in tetrads or small groups. Fabriciins studied also have a sperm structure distinct from the Sabellinae and the Serpulidae. Proposed synapomorphies for the members of the Fabriciinae, based on sperm structure, include (1) a thick glycocalyx over the plasma membrane; (2) a distinctive nuclear projection, with an anterior thickening of the nuclear membrane; (3) a thickened. spiraling ridge of nuclear membrane; (4) an extra-axonemal sheath and (5) a unique sheath of mitochondrial material in the midpiece. Within the sub-family there were differences among species in sperm structure. This variability involves acrosome morphology; the structure of the sperm nucleus and nuclear projection; the spiral of thickened nuclear membrane; the structure of the extra-axonemal sheath; the mitochondrial sheath. The monophyly of the Fabriciinae (sensu Fitzhugh, 1991, 1993) is well supported by this analysis. The status of Caobangia is still unresolved and a close examination of this genus is warranted.     

Free‐living calamyzin chrysopetalids (Annelida) from methane seeps,anoxic basins,and whale falls

Members of Calamyzinae, a clade of free‐living and ectoparasitic chrysopetalids, are mainly associated with deep‐sea chemosynthetic environments. The three currently known free‐living calamyzin species are placed in Vigtorniella. A new free‐living calamyzin species similar to these is described here. Phylogenetic analyses of Calamyzinae using mitochondrial (cytochrome c oxidase subunit I and 16S rDNA) and nuclear (Histone H3 and 18S rDNA) loci showed that Vigtorniella and the new species form a grade with respect to an ectoparasitic clade, requiring two new genera to be erected. All free‐living calamyzins show a similar anterior end and chaetal morphology. Micospina auribohnorum gen. et sp. nov. is described for the small‐bodied new species from deep‐sea whale falls off California and methane seeps off Costa Rica. The maximum‐likelihood and Bayesian analyses show Micospina gen. nov. as sister to the ectoparasitic clade. Boudemos gen. nov. is named for the clade of two larger‐bodied species: Boudemos flokati gen. et comb. nov. and Boudemos ardabilia gen. et comb. nov., which is sister group to all other Calamyzinae. Vigtorniella is retained for the type species, Vigtorniella zaikai (Kiseleva, 1992), with the adults found amongst bacterial mats at the boundary of the hydrogen sulphide zone in the Black Sea. Micospina gen. nov., Boudemos gen. nov., and Vigtorniella form a grade of free‐living taxa that is associated with feeding on organic‐enriched sediments, and the latter two taxa display ontogenetic jaw change. Jaws are absent in Micospina auribohnorum gen. et sp. nov. and most of the calamyzin clade of parasitic forms.     

A functional genetic marker for apple red skin coloration across different environments

The red skin color desired by most apple consumers is not easy to achieve in warm climates, as the expression of MYB10, which regulates red pigmentation in apple, is influenced negatively by high temperatures. We describe the development and validation of a genetic marker for red skin coloration that effectively predicts color in a warm summer environment in Spain, as well as more temperate climates in New Zealand and Italy. Following the determination of a major-effect quantitative trait locus (QTL) controlling red skin coloration on linkage group (LG)9, using four segregating populations grown in New Zealand, and screened using the IRSC apple 8-K single-nucleotide polymorphism (SNP) array, the most significant SNP marker (ss475879531) was transformed into a marker suitable for use in a real-time PCR assay. This marker was validated using five apple seedling populations growing in a warm summer environment in Spain, demonstrating that the marker system efficiently predicts red skin coloration and can be used for marker assisted selection, even under conditions considered adverse for skin color development.     

Mechanisms of antiviral immunity induced by a vaccinia virus recombinant expressing herpes simplex virus type 1 glycoprotein D: cytotoxic T cells

We used a transfected L cell and a vaccinia vector carrying the herpes simplex virus type 1 (HSV-1) gene coding for glycoprotein D (gD) to characterize HSV-specific T-cell responses. Various studies with mice revealed that the vectors could stimulate some HSV-specific T-cell responses. Although the majority of the T cells contributing to the HSV-1 gD-specific proliferative response were of the Lyt-2.1+ phenotype, cytotoxic T cells (Tc), surprisingly, were not induced by these gD vectors. Even though gD appeared to be a target for a class II major histocompatibility complex (MHC)-restricted killer cell, neither gD vector was capable of forming a target cell complex which could be recognized by class I MHC-restricted HSV-specific Tc. Further investigation of the gD-specific responses revealed the presence of potent suppressor cells and factors capable of inhibiting HSV-specific Tc induction in in vitro assays. One interpretation of these data is that class I MHC-restricted HSV- and gD-specific Tc do not develop during HSV infection because of active suppression.     

Structure of a peptide from coho salmon endocrine pancreas with homology to neuropeptide Y

The amino acid sequence of a peptide isolated from the Pacific salmon (Oncorhynchus kisutch) endocrine pancreas has been determined. This simple 36 residue peptide is a member of the pancreatic polypeptide family. It contains a C-terminal tyrosinamide and is more homologous with porcine neuropeptide Y (NPY) (83%) and peptide YY (75%) than any of the previously characterized pancreatic polypeptides (PP). This peptide appears to be the major but not the only representative of this family of peptides present in the endocrine pancreas of this fish. This peptide is referred to as salmon pancreatic polypeptide (salmon PP).     

The biosynthesis of ubiquitin by parathyroid gland

Data are presented on the isolation, biosynthesis, and identification of a small peptide (H) from parathyroid gland. Under our experimental conditions this peptide (H) represents, in addition to secretory protein-I and proparathyroid hormone, the other major protein which is rapidly synthesized during shorterm incubations of tissue slices. N-terminal sequence analysis was performed on samples of peptide H and the resulting data used to conduct a search of the sequence data bank. The search established the identity of peptide H as ubiquitin. These findings establish parathyroid gland as another system which rapidly produces ubiquitin $\text{in}$$\text{vitro}$, in addition to the systems employing hypothalamus and pituitary where ubiquitin biosynthesis was initially observed by Seidah $\text{et}$$\text{al}$ and Scherrer $\text{et}$$\text{al}$.     

Reproductive timetable for the tropical Vireya rhododendron,R. Macgregoriae

Summary The reproductive development of Rhododendron macgregoriae F.v.M., Section Vireya (Ericaceae) has been followed from 10 days before anthesis to the production of mature germinable seeds about 145 days after anthesis. The species is self-compatible but shows both protandry and physical separation of pollen from the receptive stigma. Pollen is mature and viable from shortly before anthesis until the corolla and attached anthers abscise some 9–12 days after the flowers open. Spontaneous dehiscence, however, occurs mostly in the first few days after opening. The stigma becomes receptive 6–7 days after anthesis, and nectar is produced at this time. Female gametophytes are not mature until about 10 days after anthesis. Fertilization occurs about 6–7 days after pollination, and although the endosperm commences development immediately, development of the embryo proper does not begin until some 40–45 days later. Pollinations made with fresh pollen between 5 and 14 days after anthesis were successful, but those made on dry stigmas in the first 4 days after anthesis, or on senescing pistils 21 days after anthesis, gave little or no seed set. In nature, autogamy is probably uncommon, the majority of pollinations are likely to be geitonogamous, but there is considerable potential for outcrossing.