Substrates Determine Spatial Distribution of Oxytricha bifaria (Ciliata Hypotrichida)

The extent to which a particular substrate (scratched glass) affects the distribution of a population ( Oxytricha bifaria ) that settled on it was measured, yielding the following results: (1) the species distinguishes among substrates slightly differing in the quality of their superficial scratches (average dimensions of 2, 2.8, 3.5, 6.5, 17 and 25 μm, respectively); (2) it "chooses" the preferred substrate by adopting specific differential behaviors; and (3) population cell density conditions its overall distribution.     

Selection of candidate coding DNA barcoding regions for use on land plants

An in silico screen of 41 of the 81 coding regions of the Nicotiana plastid genome generated a shortlist of 12 candidates as DNA barcoding loci for land plants. These loci were evaluated for amplification and sequence variation against a reference set of 98 land plant taxa. The deployment of multiple primers and a modified multiplexed tandem polymerase chain reaction yielded 85–94% amplification across taxa, and mean sequence differences between sister taxa of 6.1 from 156 bases of accD to 22 from 493 bases of matK. We conclude that loci should be combined for effective diagnosis, and recommend further investigation of the following six loci: matK, rpoB, rpoC1, ndhJ, ycf5 and accD. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159 , 1–11.     

Macrotrachela quadricornifera (Rotifera, Bdelloidea); a SEM Study on Active and Cryptobiotic Animals

The general morphology of Macrotrachela quadricornifera Milne, 1886 in the active and cryptobiotic states is analyzed under the scanning electron microscope. Some foot peculiarities not previously observed are reported, in particular the canaliculated spurs and presence of a sort of groove on the toes. The integument of active animals is perforated with pores and is micro-sculptured in the trunk region. During cryptobiosis, the animal is contracted, its toot and head being retracted into the trunk: the same microsculpture of the trunk integument is observed.