Polymerization of Ftsz, a bacterial homolog of tubulin. is assembly cooperative?

FtsZ is a bacterial homolog of tubulin that is essential for prokaryotic cytokinesis. In vitro, GTP induces FtsZ to assemble into straight, 5-nm-wide polymers. Here we show that the polymerization of these FtsZ filaments most closely resembles noncooperative (or "isodesmic") assembly; the polymers are single-stranded and assemble with no evidence of a nucleation phase and without a critical concentration. We have developed a model for the isodesmic polymerization that includes GTP hydrolysis in the scheme. The model can account for the lengths of the FtsZ polymers and their maximum steady state nucleotide hydrolysis rates. It predicts that unlike microtubules, FtsZ protofilaments consist of GTP-bound FtsZ subunits that hydrolyze their nucleotide only slowly and are connected by high affinity longitudinal bonds with a nanomolar K(D).     

Olpidiopsis antithamnionis n. sp. (Oomycetes,Olpidiopsidaceae), a parasite of Antithamnion floccosum (O. F. Müll.) Kleen from Newfoundland

Summary Olpidiopsis antithamnionis n. sp. (Oomycetes, Olpidiopsidaceae) parasitic on Antithamnion floccosum (O. F. Müll.) Kleen (Rhodophyta, Ceramiaceae) is described from three sites in Newfoundland, Canada, and from culture.Axial cells of the main and determinate branches of the host are the primary sites of fungal attack, although tetrasporangia and rhizoidal cells are also susceptible. Successful re-infection of A. floccosum was achieved in the laboratory although A. boreale and the trailliella-phase of Bonnemaisonia hamifera, both occurring with A. floccosum in the field, were immune. Regeneration of the host cells was observed, a phenomenon not previously reported in the fungal parasitism of other filamentous benthic marine algae.Studies in Biology from Memorial University of Newfoundland No. 256.     

Isolation of a β-Carotene Over-Producing Soil Bacterium, Sphingomonas sp.

A carotenoid-accumulating bacterium isolated from soil, identified as a Sphingomonas sp., grew at 0.18 h(-1) and produced 1.7 mg carotenoids g(-1) dry cell, among which beta-carotene (29% of total carotenoids) and nostoxanthin (36%). A mutant strain, obtained by treatment with ethyl methanesulfonate, accumulated up to 3.5 mg carotenoids g(-1) dry cell. Accumulation of beta-carotene by this strain depended on the oxygenation of the growth medium, with maximal accumulation (89%) occurring under limiting conditions. Beta-carotene accumulation could be further enhanced by incubating the cells in the presence of glycerol (either not or only slowly assimilated) and yeast extract resulting in an accumulation of 5.7 mg beta-carotene g(-1) dry cell wt. The strain used lactose as carbon source with similar biomass and carotenoid production, providing a viable alternative use for cheese whey ultra-filtrate.     

Phlebotomine sandflies (Diptera: Psychodidae) from Lábrea,state of Amazonas,Brazil, with a description of Evandromyia (Aldamyia) apurinan Shimabukuro,Figueira & Silva,sp. nov.

An entomological survey was conducted from July-December 2009 and September-December 2010, as part of the epidemiological monitoring of American cutaneous leishmaniasis (ACL) in the municipality of Lábrea, state of Amazonas (AM), Brazil. Sandflies were collected using CDC light traps installed in intra and peridomiciliary locations, as well as the border of forested areas around houses where autochthonous cases of ACL were recorded. A total of 510 sandflies belonging to 26 species were collected. The most abundant species was Nyssomyia antunesi (44.5%) followed by Evandromyia walkeri (10.6%) and Micropygomyia rorotaensis (9.8%). Here we also describe Evandromyia (Aldamyia) apurinan sp. nov. and report new records for Trichophoromyia flochi and Evandromyia sipani in AM and Brazil, respectively. Our results describe the composition of the sandfly fauna in the south of AM and suggest Ny. antunesi as the putative vector in the transmission of Leishmania in this area of the Amazon Region.     

Armatalona gen. n. – a new genus of subfamily Aloninae (Anomopoda, Chydoridae), separated from genus Alona Baird, 1840

The little-known cladoceran Alona macrocopa Sars, 1894 and four related species differ from the majority of the genus Alona by unusual morphology of antenna and postabdomen. Only two species of the five, A. macrocopa Sars, 1894 and A. imitatoria Smirnov, 1989, are found to be valid. The species A. abbreviata Sars, 1895, A. duodontha Henry, 1922 and A. guernei Smirnov, 2001 are proved to be the synonims of A. macrocopa. The detailed morphology of appendages of A. macrocopa and A. imitatoria is studied for the first time. Analysis of morphology of the macrocopa-group reveals numerous characters clearly separating it from other species of Alona despite the wide diversity of this genus. Unusual morphology of the antenna, and the female and male postabdomen does not allow placement of the macrocopa-group in any other genera of Aloninae. So the new genus Armatalona gen. n. is suggested. This new genus is the highly specialized marginal genus of Aloninae, closely related only to the Australian endemic genus Pseudomonospilus Smirnov, 2001. The morphology of Armatalona gen. n. and its place within Aloninae are discussed.     

Tabanidae (Diptera) of State of Maranhão, Brazil II. Description of Esenbeckia (Esenbeckia) rafaeli, sp. nov

Esenbeckia (Esenbeckia) rafaeli, sp.nov. is described and figured from nine specimens collected in Carolina, state of Maranh?o, Brazil. The new species is compared with the species Esenbeckia (Esenbeckia) laticlava Wilkerson & Fairchild, 1983; Esenbeckia (Esenbeckia) bitriangulata Lutz & Castro, 1935 e Esenbeckia (Esenbeckia) enderleini Kr?ber, 1931.     

The production of α-amylase (E.C.3.2.1.1.) byBacillus amyloliquefaciens,in a complex and a totally defined synthetic culture medium

The production of -amylase byBacillus amyloliquefaciens in both complex and synthetic culture media was examined at a laboratory fermenter scale. In a complex medium which supports fast growth rates, enzyme production occurred only when the growth rate declined, principally in the stationary phase. By contrast, in a synthetic culture medium with lactose as the carbon source supporting much lower growth rates, enzyme formation occurred simultaneously with cell growth. The repression of enzyme formation during rapid growth may be due either to catabolite repression or to the low level of mRNA synthesis concerned with the production of exoproteins.     

Description of Lutzomyia (Lutzomyia) falquetoi sp. nov. (Diptera: Psychodidae, Phlebotominae) a new species from the state of Espírito Santo, Brazil

Lutzomyia (Lutzomyia) falquetoi, sp. nov. (Diptera: Psychodidae, Phlebotominae) is described from the state of Espírito Santo, Brazil. This new species belongs to the series longipalpis and is easily distinguished from the other members of this taxon by the presence of five well-developed spines and a pre-apical spiniform bristle on the gonostyle as well as nine bristles on the basal tuft of the gonocoxite.     

Myrmechis bakhimensis D. Maity, N. Pradhan ＆ G. G. Maiti, a new species of Orchidaceae from Sikkim Himalaya

Myrmechis bakhimensis D. Maity,N. Pradhan & G. G. Maiti (Orchidaceae),a new species from Sikkim Himalaya,is described and illustrated. The new species most closely resembles M. japonica (Reichb.) Rolfe and M. chinensis Rolfe with similar shape and size of lamina and the “T”-shaped epichile,but differs by the perfectly glabrous and eciliate floral bract,5-nerved dorsal sepal,and emarginate,mucronate epichile.     

Neotropical monogenea. 13. Rhinonastes pseuodocapsaloideum n. gen., n. sp. (Dactylogyridae, Ancyrocephalinae), a nasal parasite of curimat?, Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae), in Brazil

Rhinonastes pseudocapsaloideum n. sp. (Dactylogyridae, Ancyrocephalinae) is described from the nasal cavity of Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae) in Brazil. Rhinonastes n. gen. is proposed for species possessing a dextroventral genital pore, a bilobed testis, a ventral C-shaped ovary lying between the 2 testicular lobes, and a disc-shaped haptor armed with a ventral anchor-bar complex and 14 hooks.     

?Kenyaichthyidae fam. nov. and ?Kenyaichthys gen. nov. – First Record of a Fossil Aplocheiloid Killifish (Teleostei,Cyprinodontiformes)

The extant Cyprinodontiformes (killifishes) with their two suborders Cyprinodontoidei and Aplocheiloidei represent a diverse and well-studied group of fishes. However, their fossil record is comparatively sparse and has so far yielded members of the Cyprinodontoidei only. Here we report on cyprinodontiform fossils from the upper Miocene Lukeino Formation in the Tugen Hills of the Central Rift Valley of Kenya, which represent the first fossil record of an aplocheiloid killifish. A total of 169 specimens - mostly extraordinarily well preserved - and a sample of ten extant cyprinodontiform species were studied on the basis of morphometrics, meristics and osteology. A phylogenetic analysis using PAUP was also conducted for the fossils. Both the osteological data and the phylogenetic analysis provide strong evidence for the assignment of the fossils to the Aplocheiloidei, and justify the definition of the new family †Kenyaichthyidae, the new genus †Kenyaichthys and the new species †K. kipkechi sp. nov. The phylogenetic analysis unexpectedly places †Kenyaichthys gen. nov. in a sister relationship to the Rivulidae (a purely Neotropical group), a probable explanation might be lack of available synapomorphies for the Rivulidae, Nothobranchiidae and Aplocheilidae. The specimens of †K. kipkechi sp. nov. show several polymorphic characters and large overlap in meristic traits, which justifies their interpretation as a species flock in statu nascendi. Patterns of variation in neural and haemal spine dimensions in the caudal vertebrae of †Kenyaichthys gen. nov. and the extant species studied indicate that some previously suggested synapomorphies of the Cyprinodontoidei and Aplocheiloidei need to be revised.     

Metabolism of the Lathyrus sativus L. Neurotoxin, β-N-Oxalyl-L-α, β-diaminopropionic Acid,by a Pure Culture of a Soil-borne Microbe

Pure cultures of bacteria capable of utilizing the Lathyrus sativus L. neurotoxin, β-N-oxalyl-L-α, β-diaminopropionic acid (ODAP), as their sole carbon and nitrogen source have been isolated from soil-sludge filtrates. Three independent isolates, designated BYA1, BYT1, and BYK1, were selected by repetitive growth on the neurotoxin and purified based upon their antibiotic resistance. Of the three Isolates, strain BYA1 demonstrated the highest capacity for ODAP utilization, degrading greater than 98% of the ODAP present In the culture media within 12 h. Using a variety of morphological and biochemical criteria BYA1 was Identified as an Enterobacter cloacae. The bacterium harbors a single large plasmid (designated pBYA1) approximately 40–50 kb in size that contains the genetic Information for ODAP utilization and antibiotic resistance. Transformation experiments with E. coli recipient strains were used to further define the location of the sequences involved in ODAP metabolism.