Cladistic analysis of the subfamilies within the Tubificidae (Oligochaeta)

A hypothesis of phylogenetic relationships within the family Tubificidae is presented, based on a Wagner analysis of morphological characters in the different subfamilies. Two major lincages are recognized. One, including the subfamilies Tubificinae, Telmatodrilinae and Limnodriloidinae, is supported by a synapomorphic ability to form slender spermatozeugmata in the spermathecae; the other, including Rhyacodrilinae (paraphyletic), Phallodrilinae, and the (present family) Naididae, is supported by two synapomorphics, the possession of modified penial setae and numerous coelomocytes (the latter secondarily lost in the Phallodrilinae). Some implications for the classification of the Tubificidae are discussed.     

Taxonomic Studies on the Marine Genera Aktedrilus Knöllner and Bacescuella Hrabe' (Oligochaeta, Tubificidae), with Descriptions of Seven New Species

The taxonomy and morphology of Aktedrilus Knöllner, 1935 and Bacescuella Hrabe' 1973 (subfamily Phallodrilinae), both common genera of the marine, littoral meiofauna, were studied on the basis of material from various geographical areas. A. monospermathecus Knöllner, 1935 is redescribed from France and Scotland. A. magnus sp.n., A. hrevis sp.n., A. curvipenis sp.n. and A. floridensis sp.n. are described from Italy, Brazil, France and Florida, respectively. Two very closely related forms are described from the Pacific: A. locyi sp.n. (California) and A. parviprostatus sp.n. (Great Barrier Reef). B. mediterranea sp.n. is described from Italy, and new European records are given forB. arclica Erséus, 1978 andfi. parvithecata Erséus, 1978. Both genera are characterized by having two pairs of prostate glands, well developed penes, and unpaired, mid-dorsal spermatheca (if present). The species of Bacescuella transfer their sperm by means of external spermatophores, structures that are not developed in Aktedrilus. The eight species of Aktedrilus are largely distinguished by means of the morphology of the spermatheca, penes and prostates. The four species of Bacescuella differ principally from each other in the length of the vasa deferentia, and in the morphology of the prostates and copulatory organs. Most Bacescuella species lack spermatheca.     

Mathematical modeling of in vitro enzymatic production of 2-Keto-L-gulonic acid using NAD(H) or NADP(H) as cofactors

A 2-Keto-L-gulonic acid (2-KLG) production process using stationary Pantoea citrea cells and a Corynebacterium 2,5-diketo-D-gluconic acid (2,5-DKG) reductase enzyme has been developed which may represent an improved method of vitamin C biosynthesis. Experimental data was collected using the F22Y/A272G 2,5-DKG reductase mutant and NADP(H) as a cofactor. An extensive kinetic analysis was performed and a kinetic rate equation model for this process was developed. A recent protein engineering effort has resulted in several 2,5-DKG reductase mutants exhibiting improved activity with NADH as a cofactor. The use of NAD(H) in the bioreactor may be preferable due to its increased stability and lower cost. The kinetic parameters in the rate equation model have been replaced in order to predict 2-KLG production with NAD(H) as a cofactor. The model was also extended to predict 2-KLG production in the presence of a range of combined cofactor concentrations. This analysis suggests that the use of the F22Y/K232G/R238H/A272G 2,5-DKG reductase mutant with NAD(H) combined with a small amount of NADP(H) could provide a significant cost benefit for in vitro enzymatic 2-KLG production.     

The Effect of a Quaternary Amine (Aliquat 336) on Growth and Photosynthesis of the Green Alga Chlorella emersonii, and the Effect on Photosynthesis in Isolated Spinach Chloroplasts

A quaternary amine, Aliquat 336, inhibits the growth of the green alga Chlorella emersonii, ¹⁴C-fixation of the alga is also inhibited. The effect and the site of action of the compound was studied by using isolated spinach chloroplasts. The carbon dioxide dependent oxygen evolution of the chloroplasts is inhibited directly upon the addition of the amine and the oxygen evolution is replaced by an oxygen uptake. By investigating some electron transport reactions in the chloroplasts we were able to show that Aliquat 336 affects the electron transport on the level of photophosphorylation. The results from the in vivo and the in vitro experiments thus show that the quaternary amine affects the photosynthetic process. Aliquat 336 is a solvent extractant used in several industrial processes for extraction of metals from aqueous solutions. Aliquat 336 could be considered a presumptive water pollutant as the compound could enter a recipient water body and thus affect photosynthesis.     

Substrate specificity of a maize ribosome-inactivating protein differs across diverse taxa.

The superfamily of ribosome-inactivating proteins (RIPs) consists of toxins that catalytically inactivate ribosomes at a universally conserved region of the large ribosomal RNA. RIPs carry out a single N-glycosidation event that alters the binding site of the translational elongational factor eEF1A and causes a cessation of protein synthesis that leads to subsequent cell death. Maize RIP1 is a kernel-specific RIP with the unusual property of being produced as a zymogen, proRIP1. ProRIP1 accumulates during seed development and becomes active during germination when cellular proteases remove acidic residues from a central domain and both termini. These deletions also result in RIP activation in vitro. However, the effectiveness of RIP1 activity against target ribosomes remains species-dependent. To determine the potential efficiency of maize RIP1 as a plant defense protein, we used quantitative RNA gel blots to detect products of RIP activity against intact ribosomal substrates from various species. We determined the enzyme specificity of recombinant maize proRIP1 (rproRIP1), papain-activated rproRIP1 and MOD1 (an active deletion mutant of rproRIP1) against ribosomal substrates with differing levels of RIP sensitivity. The rproRIP1 had no detectable enzymatic activity against ribosomes from any of the species assayed. The papain-activated rproRIP1 was more active than MOD1 against ribosomes from either rabbit or the corn pathogen, Aspergillus flavus, but the difference was much more marked when rabbit ribosomes were used as a substrate. The papain-activated rproRIP1 was much more active against rabbit ribosomes than homologous Zea mays ribosomes and had no detectable effect on Escherichia coli ribosomes.