STUDIES WITH CYANIDIUM CALDARIUM : I. The Fine Structure and Systematic Position of the Organism

The fine structure of Cyanidium caldarium, as seen in thin sections of KMnO₄-fixed cells examined with the electron microscope, is described. This organism, whose taxonomic position among algae is undetermined, contains a single well defined chloroplast, a nucleus, and mitochondria. Studies, with the electron microscope, of Chlorella pyrenoidosa and Nostoc are also reported. Structural differences within cells of Cyanidium, chlorella, and Nostoc are discussed. It is concluded that if Nostoc can be taken as a typical Cyanophyte and Chlorella as a representative Chlorophyte and if the items of fine structure examined are diagnostic, then Cyanidium is certainly not a Cyanophyte and, while it has numerous features in common with Chlorella, is not a green alga similar to Chlorella. Comparisons are also made between Cyanidium and other algae whose fine structure has been described by others.     

Revision of the European species of Omphale Haliday (Hymenoptera,Chalcidoidea, Eulophidae)

The European species of Omphale Haliday (Eulophidae: Entedoninae) are revised. The revision includes 37 species, of which eleven are newly described and the remaining 26 species are redescribed. The species are classified into six species groups, with six unplaced species. All species are fully diagnosed and thoroughly illustrated. Identification keys are provided for females and males. Two new morphological features to aid classification and identification are introduced: male genitalia and wing interference patterns (WIPs). The former has been used successfully in the classification of New World Omphale and the latter is used for the first time in a taxonomic revision. Male genitalia in Omphale have considerable interspecific variation, an unusual trait among chalcidoid Hymenoptera, and are demonstrated to be useful for classification of species and species-groups, and they also possess the only autapomorphy for Omphale. WIPs are useful to help separate some species, but cannot be used to define either the genus or species groups. Distributional data are compiled for each species and suggest a pan-european distribution for most species. Gall-midges are the known hosts for 14 species, and the absence of host overlap between species suggests that host specialization is a driving force for speciation. Several Omphale species are known only from females, or have a strong female biased sex ratio, suggesting thelytokous development. Apart from the 37 species included in this revision, the status for nine additional species (names) in species group aetius remain unsolved. For nomenclatorial stability, a neotype is designated for Eulophus lugens Nees (= Omphale lugens (Nees)). Elachestus obscurus Förster and Derostenus sulciscuta Thomson are transferred from Holcopelte to Omphale comb. n. Derostenus radialis Thomson and Achrysocharella americana Girault are synonymized with Omphale theana (Walker), and Omphale teresis Askew is synonymized with Omphale phruron (Walker), syn. n. The status of genus Pholema Graham is revised as it is removed from synonymy with Omphale and instead synonymized with Neochrysocharis Kurdjumov, syn. n., and the type species for Pholema, Pholema microstoma Graham, is transferred to Neochrysocharis, comb. n. Eugerium orbatum Szelényi, previously transferred to Omphale, is synonymized with Asecodes congruens (Nees), syn. n.     

Epidemics and vaccination on weighted graphs

A Reed-Frost epidemic with inhomogeneous infection probabilities on a graph with prescribed degree distribution is studied. Each edge (u, v) in the graph is equipped with two weights W_(u,v) and W_(v,u) that represent the (subjective) strength of the connection and determine the probability that u infects v in case u is infected and vice versa. Expressions for the epidemic threshold are derived for i.i.d. weights and for weights that are functions of the degrees. For i.i.d. weights, a variation of the so called acquaintance vaccination strategy is analyzed where vertices are chosen randomly and neighbors of these vertices with large edge weights are vaccinated. This strategy is shown to outperform the strategy where the neighbors are chosen randomly in the sense that the basic reproduction number is smaller for a given vaccination coverage.     

Redescription of Three Ektaphelenchus Species (Nematoda: Aphelenchina)

Three Ektaphelenchus species with unusual spicules are redescribed. Ektaphelenchus obtusus and E. riograndensis are redescribed from newly discovered material in the collection of the USDA Forest Service RMRS. Lectotype slides are designated for both species. Ektaphelenchus obtusus is characterized by a set-off head, lips of unequal size, double rows of oocytes and spermatocytes, and a hooked spicule terminus. Ektaphelenchus riograndensis is distinguished by a rounded head with six equal lips, and spicules with a large, rounded apex, and recurved terminus. A bursa and gubernaculum are absent in both species. Ektaphelenchus scolyti is redescribed from type material deposited in the collection of Rothamsted Experimental Station. It is characterized by a well set-off head, double rows of oocytes and spermatocytes, and spicules with a hooked terminus. A bursa and gubernaculum are absent.     

Bacteriology of Most Frequent Oral Anaerobic Infections

The anaerobic infections most frequently found in the oral cavity are gingivoperiodontal diseases and pulpal and periapical infections. Gingivitis and adult periodontitis are the most frequent forms. In adult periodontitis the subgingival microbiota are complex and there is a prevalence of Porphyromonas gingivalis, Prevotella intermedia,Prevotella nigrescens , Actinobacillus actinomycetemcomitans, Bacteroides forsythus,Peptostreptococcus micros , Campylobacter rectus, and species of Fusobacterium, Eikenella andTreponema .The microflora associated with peri-implant infections are similar to the microflora found in periodontal diseases, particularly in partially edentulous patients. Implant placement is therefore not recommended in patients presenting with uncontrolled periodontal disease.Likewise, there is a similarity between the genera identified in periodontal pockets and infected root canals, and in periapical infections. However, some species are more prevalent than others in both infections. The following were predominantly observed inside the root canals: Prevotella intermedia, Prevotella nigrescens,Peptostreptococcus anaerobius , Peptostreptococcus micros, Eubacterium lentum, Eubacterium alactolyticum and Porphyromonas endodontalis, with strong associations among some species.Pericoronaritis is another infection associated with anaerobic Gram-negative bacilli and treponeme. There are a great number of methods for microbiological diagnosis, and treatment of some oral infections depends on close interaction between the microbiologist and the dentist.     

Low-temperature magnetic circular dichroism evidence for the conversion of four-iron-sulphur clusters in a ferredoxin from Clostridium pasteurianum into three-iron-sulphur clusters

Oxidation of the 8Fe ferredoxin from Clostridium pasteurianum with potassium ferricyanide, followed by purification on Sephadex G-25 and DE-23 cellulose columns, gives a protein with an intense EPR signal at g 2.01. The low-temperature magnetic circular dichroism (MCD) spectra of this species are different from those of the oxidized high-potential iron protein from Chromatium but identical with the spectra of ferredoxin II from Desulphovibrio gigas. On reduction of the ferricyanide-treated ferredoxin with sodium dithionite only a weak EPR signal with g factors of 2.05, 1.94 and 1.89 is obtained. The low-temperature MCD spectra are strongly temperature dependent with a form similar to those of dithionite-reduced D. gigas ferredoxin II. The MCD magnetization curves are dominated by a species with ground-state effective g factors of $\text{g}{}_{\mathrm{?}}$ 8.0 and g_⊥ 0.0, which are also similar to those determined recently by low-temperature MCD spectroscopy for D. gigas ferredoxin II. The MCD characteristics are quite different from those of dithionite-reduced ferredoxin from Cl. pasteurianum, untreated with ferricyanide. This establishes the close similarity of the iron-sulphur clusters in ferricyanide-treated Cl. pasteurianum ferredoxin and in D. gigas ferredoxin II. The latter is known to contain a single 3Fe centre, similar to that observed in ferredoxin I from Azotobacter vinelandii by X-ray crystallography. Therefore, it is concluded that the [4Fe-4S] clusters of Cl. pasteurianum ferredoxin are converted to 3Fe clusters on oxidation with ferricyanide.     

Chemicobiological interactions and the use of partition coefficients in their correlation

Using octanol/water partition coefficients as an operational definition of hydrophobicity, 70 examples are given in which the hydrophobic interactions of organic compounds with themselves (in micelles) with macromolecules or with biological systems can be quantitatively correlated by the expression: log RBR = a log P + b. In this expression RBR is a binding constant or a relative biological response, P is the octanol/water partition coefficient and a and b are constants obtained via the method of least squares. These results are strong support for the utility of log P in the correlation of hydrophobic interactions. They also illustrate the extremely wide range of processes in which hydrophobic bonding plays a critical role.     

Taxonomic revision of the genus Callimerus Gorham s. l. (Coleoptera,Cleridae). Part I. latifrons species-group

The latifrons species-group (=Brachycallimerus sensu Chapin 1924, Corporaal 1950; = flavofasciatus-group sensu Kolibáč 1998) of Callimerus Gorham is redefined and revised. Five species are recognized including one new species Callimerus cacuminis Yang & Yang sp. n. (type locality: Yunnan, China). Callimerus flavofasciatus Schenkling, 1902 is newly synonymized with Callimerus latifrons Gorham, 1876. Callimerus trifasciatus Schenkling, 1899a is transferred to the genus Corynommadius Schenkling, 1899a. Callimerus gorhami Corporaal, 1949 and Callimerus pallidus Gorham, 1892 are excluded from the latifrons species-group (their assignment to a species-group will be dealt with in a subsequent paper). A key to species of the latifrons species-group is given and habitus of each type specimen, male terminalia, and other diagnostic characters are illustrated.     

A new Brazilian Passiflora leafminer: Spinivalva gaucha,gen. n., sp. n. (Lepidoptera,Gracillariidae, Gracillariinae), the first gracillariid without a sap-feeding instar

Male, female, pupa, larva and egg of a new genus and species of Gracillariidae (Gracillariinae), Spinivalva gaucha Moreira and Vargas from southern Brazil are described and illustrated with the aid of optical and scanning electron microscopy. A preliminary analysis of mitochondrial DNA sequences including members of related lineages is also provided. The immature stages are associated with Passiflora actinia, Passiflora misera and Passiflora suberosa (Passifloraceae), and build mines on the adaxial leaf surface. Initially the mines are serpentine in shape, but later in larval ontogeny become a blotch type. Although the larvae are hypermetamorphic as in other Gracillariidae, there is no sap-feeding instar in Spinivalva gaucha; the larva feeds on the palisade parenchyma, thus producing granular frass during all instars. Pupation occurs outside the mine; prior to pupating, the larva excretes numerous bubbles that are placed in rows on the lateral margins of the cocoon external surface. This is the second genus of gracillariid moth described for the Atlantic Rain Forest, and the second gracillariid species known to be associated with Passifloraceae.     

Notch2 is required for maintaining sustentacular cell function in the adult mouse main olfactory epithelium

Notch receptors are expressed in neurons and glia in the adult nervous system, but why this expression persists is not well-understood. Here we examine the role of the Notch pathway in the postnatal mouse main olfactory system, and show evidence consistent with a model where Notch2 is required for maintaining sustentacular cell function. In the absence of Notch2, the laminar nature of these glial-like cells is disrupted. Hes1, Hey1, and Six1, which are downstream effectors of the Notch pathway, are down-regulated, and cytochrome P450 and Glutathione S-transferase (GST) expression by sustentacular cells is reduced. Functional levels of GST activity are also reduced. These disruptions are associated with increased olfactory sensory neuron degeneration. Surprisingly, expression of Notch3 is also down-regulated. This suggests the existence of a feedback loop where expression of Notch3 is initially independent of Notch2, but requires Notch2 for maintained expression. While the Notch pathway has previously been shown to be important for promoting gliogenesis during development, this is the first demonstration that the persistent expression of Notch receptors is required for maintaining glial function in adult.     

Lepidasthenia loboi sp. n. from Puerto Madryn,Argentina (Polychaeta,Polynoidae)

Among polychaetes, polynoids have the highest number of symbiotic species found living with a wide variety of marine invertebrates, including other polychaetes. Lepidasthenia Malmgren, 1867 and Lepidametria Webster, 1879 were regarded as synonyms but belong to different subfamilies, although both have species associated with thelepodid or terebellid polychaetes. In this contribution Lepidasthenia loboi sp. n. is described from several specimens associated with the thelepodid Thelepus antarcticus Kinberg, 1867, collected on a rocky shore near Puerto Madryn, Argentina. Lepidasthenia loboi sp. n. can be confused with Lepidasthenia esbelta Amaral & Nonato, 1982 because both live with Thelepus, are of similar sizes with similar pigmentation patterns, and have giant neurochaetae. However, in Lepidasthenia loboi sp. n. all eyes are of the same size, cephalic and parapodial cirri are tapered and mucronate, the second pair of elytra is larger than the third, the ventral cirri arise at the base of parapodia such that they do not reach chaetal lobe tips, and neuraciculae are tapered. On the contrary, in Lepidasthenia esbelta the posterior eyes are larger than anterior ones, cephalic and parapodial appendages are swollen subdistally, the second and third pairs of elytra are of the same size, the ventral cirri arise medially such that their tips reach the neurochaetal lobe tips, and the neuraciculae have falcate tips. Some comments about other genera in the Lepidastheniinae, a simplified key to its genera, and a key to Lepidasthenia species with giant neurochaetae are also included.     

Annotated checklist of marine fishes from the Sanctuary of Bahía Chamela,Mexico with occurrence and biogeographic data

An annotated checklist of marine fishes of the Sanctuary of Islands and Islets of Bahía Chamela in the central Mexican Pacific is presented. Records of fish species were obtained by different methods including visual census, sampling with anesthetics, fisherman-nets, and trawling with a biological dredge. Additional records were obtained from natural history collections and publications. The list comprises 196 species in 64 families and 141 genera. The Carangidae is the most speciose family with 11 species, followed by the Labridae with 10 and the Pomacentridae with nine. Fourteen species are endemic in Mexican Pacific waters, but none is restricted to Bahía Chamela. The most dominant species recorded during underwater surveys were Epinephelus labriformis, Stegastes flavilatus, and Halichoeres dispilus. Most species are of tropical affinities distributed throughout the tropical eastern Pacific (123), eastern Pacific (23), and Mexican Pacific (14). Other species are known from the eastern and Indo-Pacific regions (18), eastern Pacific and western Atlantic oceans (2), and some are circumtropical (9). A new record of the Gulf Brotula Ogilbia ventralis is provided for the Bahía Chamela and its geographical distribution is extended to Mexican central Pacific.     

Relationships of the purple-fringed orchids Platanthera Psycodes and P. grandiflora

The vegetative and floral differences between two frequently confused species are discussed in terms of function.Platanthera psycodes is a widespread species with flowers adapted to visits by short-tongued lepidoptera, especially skippers of the genusPolites; the pollinaria are attached to the base of the proboscis.Platanthera grandiflora is a geographically more limited species with flowers adapted to visits by longer-tongued lepidoptera; the pollinaria are probably attached to compound eyes. The species overlap geographically and phenologically. Chromosome numbers are 2n = 42 in each species. Cultivated plants of each are partially self-incompatible but produce apparently normal embryos when intercrossed. Mechanical, seasonal, ethological, and distributional differences isolate the species.Habenaria andPlatanthera are considered distinct but closely related genera.Platanthera psycodes is based upon a type at L,P. grandiflora on a type at AMES.Platanthera grandiflora andP. psycodes have affinities with three other eastern North American species characterized by tripartite, fringed, or erose labella. Species pairs within this group, based on column structure, includegrandifloraperamoena andpsycodeslacera. The column ofP. leucophaea is morphologically intermediate in form.     

Distance of the reduced Brusselator from equilibrium

The new concept of a nonequilibrium parameter P is applied to a reduced Brusselator, considered as a kinetic model for cellular processes. The reduction corresponds to omitting a monomolecular reaction. The deviation from equilibrium is due to a fixed nonequilibrium value of an extracellular concentration B, responsible for energizing and determining the steady-state value of the overall chemical affinity ?. The value of ? is insensitive to different steady states possible for a given set of rate constants. In contrast, the parameter P is state dependent. In particular, it may jump together with state variables. Two limiting cases of high ? are investigated, B→ 0 and B→ 1. In the first case P grows monotonically with ?. In the second case there is always a steady state solution with P→ 0. The physical interpretation of this effect of “equilibrium far from equilibrium” reveals the real predictive power of the parameter P. Relaxation regimes are investigated for a doubly reduced Brusselator. Both P and ? are in general time dependent and have jumps in their time derivatives. The canonical form of P is compared with the noncanonical one in the context of robustness of the new concept with respect to incomplete information about the system studied. These forms of P are different in relaxation to a nonequilibrium state and coincide in relaxation to an equilibrium state.     

Geographical variation in Fennoscandian and Estonian Schoenus wetlands

Using TABORD five Schoenus ferrugineus associations have been distinguished from the literature. They are well distinguished by differential-species combinations and most of them are described earlier under identical names, e.g., the Primula-, Oxycoccus-, Myrica-, and Trichophorum-Schoenus ferrugineus ass. The Thalictrum-Schoenus ferrugineus ass. is a new syntaxon. They are further characterized by different floristic elements according to their geographical distribution. The Primula-Schoenus ferrugineus ass. is related to Central Europe, the Primulo-Schoenetum ferruginei from Oberd. (1957) 1962. All other associations discussed have no counterparts elsewhere in Europe. The shortcoming of this classification and the impossibility of a syntaxonomical ranking are emphasized. The variation in species composition and site conditions is elucidated by RA ordination. A complex soil moisture gradient is related to the differences in species composition between the Primula-, Oxycoccus-, and Myrica-Schoenus ferrugineus ass. Wet topogenous mire sites with peat formation and a rather low pH is typical of the Myrica-Schoenus ferrugineus ass., while the Primula-Schoenus ferrugineus ass. occurs either in moist soligenous mire sites or in to pogenous sites with strongly shifting water tables and with muck (Anmoor) instead of peat. The site conditions of the Oxycoccus-Schoenus ferrugineus ass. are most similar to those of the Myrica-Schoenus ferrugineus ass. The Trichophorum- and Thalictrum-Schoenus ferrugineus ass. occur on soligenous mire sites.