Size scaling of whole‐body metabolic activity in the noble crayfish (Astacus astacus) estimated from measurements on a single leg

1. Use of electron transport system (ETS) activity in a single leg for estimating whole‐body ETS activity was explored in the noble crayfish Astacus astacus. Oxygen consumption and ETS activity of the whole body and of a walking leg were measured in different‐sized animals at 10 °C to compare the size scaling of oxygen consumption, whole‐body ETS activity and the ratio of whole‐body ETS activity to oxygen consumption (ETS/R). 2. Electron transport system activity of a leg and the ratio of ETS activity of a whole crayfish to that of a leg were correlated with wet mass of animals. Therefore, metabolic potential in whole noble crayfish can be estimated on the basis of the measured ETS activity in a single leg and crayfish mass. This approach provides a valuable tool for determining metabolic characteristics of crayfish without killing them. 3. Mass‐specific oxygen consumption decreased with increasing wet mass, while ETS activity of whole crayfish showed no significant correlation with wet mass. Both oxygen consumption and ETS activity correlated significantly with protein mass. 4. The increase in ETS/R with increasing wet mass of the noble crayfish indicates that small organisms exploit a greater proportion of their metabolic potential for standard metabolism than larger ones. This is the first report on ETS/R in crayfish.     

Description of Paratetrahymena parawassi n. sp. using Morphological and Molecular Evidence and a Phylogenetic Analysis of Paratetrahymena and Other Taxonomically Ambiguous Genera in the Order Loxocephalida (Ciliophora,Oligohymenophorea)

ABSTRACT. The marine scuticociliate Paratetrahymena parawassi n. sp. is described on the basis of morphology, especially infraciliature, and the sequence of its small subunit (SSU) rRNA gene to become the second known member of its genus. Paratetrahymena and other ciliates in the order Loxocephalida possess a mixture of morphological and morphogenetic features characteristic of the subclasses Hymenostomatia and Scuticociliatia. Accordingly, we used SSU rRNA sequences to analyze the phylogeny of Paratetrahymena and three other loxocephalid genera. Paratetrahymena and Cardiostomatella vermiformis formed a moderately well‐supported clade that diverged at a deep level from all other scuticociliates, supporting separation of loxocephalids from other scuticociliates as a suprafamilial taxon. Sathrophilus holtae was a sister taxon to Paratetrahymena and Cardiostomatella in a poorly supported, unresolved relationship; nevertheless, association of all three genera into a single clade was supported by an approximately unbiased (AU) test. Any association of these genera singly or as a group with the Hymenostomatia was rejected decisively by AU tests and by a complete absence in the loxocephalids of the unique nucleotide identities that distinguish hymenostomes. Therefore, the morphological and morphogenetic similarities of loxocephalids to hymenostomes may be plesiomorphies, and the conflicting mix of scuticociliate and hymenostome characteristics seen in loxocephalids may result from differing rates of character evolution. Dexiotrichides pangi and Urocentrum, which is currently classified as a peniculid, formed a small clade that associated with hymenostomes and peritrichs. Monophyly of the Loxocephalida with Dexiotrichides and/or Urocentrum included was not rejected by AU; however, inclusion of Urocentrum in the Peniculia was rejected by AU tests. A hypothesis is offered to explain the lack of resolution of loxocephalid ciliates and Urocentrum in phylogenetic trees, namely that their phylogenetic positions are influenced by a combination of heterogeneous data and long‐branch attraction caused by poor representation of taxa in analyses. The well‐known genus Cyclidium, a member of the order Pleuronematida, was revealed to be polyphyletic as a byproduct of our analyses of loxocephalids. In particular, Cyclidium porcatum appears to fall outside the clade containing typical members of the subclass Scuticociliatia and thus invites investigation as a possible member of the order Loxocephalida.     

Competitive cobalt for zinc substitution in mammalian methionine sulfoxide reductase B1 overexpressed in E. coli: structural and functional insight

Expression of the mammalian enzyme methionine sulfoxide reductase B1 (MsrB1) in Escherichia coli growing in cobalt-containing media resulted in the reproducible appearance of the stable cobalt-containing protein MsrB1-Co. NMR studies and biocomputing using the programs AnisoFit and Amber allowed us to generate a structure of MsrB1-Co sharing the overall fold with the native zinc-containing protein MsrB1-Zn. Our data suggest that the N-terminus containing resolving cysteine tends to be closer to the protein’s catalytic center than was previously reported. It is argued that this proximity supports the proposed catalytic mechanism and ensures high catalytic efficiency of MsrB1. Functional studies showed that both MsrB1-Zn and MsrB1-Co exhibit similar levels of activity, in agreement with the structural studies performed. The proposed metal ion substitution approach may have a methodological significance in determining whether methionine sulfoxide reductase B proteins contain a metal ion.     

Determination of aflatoxin levels in peanut butter using HPLC and ELISA procedures: Inter-laboratory comparison

Mycotoxin Research - Six laboratories analyzed portions of the same aqueous acetonitrile extracts of three peanut butters for aflatoxin concentrations by an HPLC procedure (using immunoaffinity...     

Performance of polyvoltine silkworm Bombyx mori L. on different mulberry plant varieties

Five cultivated mulberry plant varieties, BSRM‐34, BSRM‐56, BSRM‐57, BSRM‐58 and BSRM‐59, were used to evaluate the effects of plant variety on larval and cocoon characteristics of mulberry silkworm Bombyx mori L. Silkworm larvae undergo their entire larval periods on leaves of mulberry varieties. Different larval characteristics of larval weight, larval length and larval breadth were measured in different growth stages. After rearing, the fifth instar larvae were transferred into a mountage (Chandraki) structure for cocoon rearing for spinning and cocoon production. The cocoons were then harvested and different cocoon characteristics like cocoon weight, shell weight and shell percentage; and other characters like pupal weight and effective rate of rearing were measured. The results showed statistically significant differences among different varieties on larval and cocoon characteristics. The highest performance was observed by feeding the variety BSRM‐34 in respect of the average weight of 10 mature larvae (40.5 g), single mature larval length (7.6 cm) and breadth (1.0 cm), single cocoon weight (1.4 g), shell weight (0.2 g) and pupal weight (1.2 g) while the average performance was recorded by feeding varieties BSRM‐57 and BSRM‐59. The poorest performance was showed by feeding the variety BSRM‐56 (in case of larval characters) and BSRM‐58 (in case of cocoon characteristics). These two varieties also showed the poorest performance for silk yield. Through comparing all the above parameters it was concluded that BSRM‐34 is the best mulberry variety and it is recommended that Bangladeshi farmers adopt that variety for better yield of silk.     

Eimeria saudiensis N. Sp. (Apicomplexa: Eimeriidae) from the Arabian Oryx (Oryx leucoryx) in Saudi Arabia

Oocysts of Eimeria saudiensis n. sp. (Apicomplexa: Eimeriidae) are described from the feces of the Arabian oryx, Oryx leucoryx , from the Riyadh Zoo, Saudi Arabia. The oocysts were ellipsoidal or slightly ovoid, 31.2 times 24.5 (24.3–36.5 times 20.0–27.6) μm with a bilayered wall about 1.7 μm thick. The micropyle was covered by a dome-shaped cap. The oocyst residuum was absent, but tiny polar granules were present. The sporocysts were elongate ovoid, 14.3 times 7.2 (11.5–18.5 times 6.0–9.0) μm, had a Stieda body, but lacked a substiedal body. The sporocyst residuum was present, composed of numerous small granules. The sporozoites were elongate club-shaped, and contained two prominent refractile bodies.