Taxonomy of five species of cyrtophorids (Protozoa: Ciliophora) including consideration of the phylogeny of two new genera

Cyrtophorids are a specialized group of ciliated protozoa with multitudinous morphotypes. In the present work, the morphology and infraciliature of two new and three rarely known species, including two new genera of cyrtophorid ciliates, Heterohartmannula fangi gen. et sp. nov. , Aporthotrochilia pulex (Deroux, 1976) gen. et comb. nov. , Trochilia alveolata sp. nov. , Trochochilodon flavus Deroux, 1976, and Hypocoma acinetarum Collin, 1907, are described. Heterohartmannula gen. nov. is mainly characterized by a combination of features: two circumoral kineties obliquely arranged, podite not surrounded by somatic kineties, and no distinct gap between left and right ciliary field. Aporthotrochilia gen. nov. is diagnosed mainly by: podite present, oral ciliature reduced to two fragments, several kinety fragments positioned on the right posterior of frontoventral kineties and several terminal fragments. Phylogenetic analyses based on the small subunit rRNA (SSU rRNA) gene sequences support the establishment of two new genera and indicate that Heterohartmannula is most closely related to Hartmannula, and Aporthotrochilia is basal to the Cyrtophoria‐Chonotrichia clade. Trochilia alveolata sp. nov. differs from its congeners mainly by having a conspicuous alveolar layer. In addition, detailed live and infraciliature data of Hypocoma acinetarum and Trochochilodon flavus are supplied. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 1–17.     

A comparison of nitrate transport in four different rice(Oryza sativa L.) cultivars

As rice can use both nitrate (NO3-) and ammonium (NH4+), we have tested the hypothesis that the shift in the pattern of cultivars grown in Jiangsu Province reflects the ability of the plants to exploit NO3- as a nitrogen (N) source. Four rice cultivars were grown in solution culture for comparison of their growth on NO3- and NH4+ nitrogen sources. All four types of rice, Xian You 63 (XY63), Yang Dao 6 (YD), Nong Keng 57 (NK) and Si You 917 (SY917), grew well and produced similar amounts of shoot biomass with 1 mmol/L NH4+ as the only N source. However, the roots of NK were significantly smaller in comparison with the other cultivars. When supplied with 1 mmol/L NO3- YD produced the greatest biomass; while NK achieved the lowest growth among the four cultivars. Electrophysiological measurements on root rhizodermal cells showed that the NO3- elicited changes in membrane potential (△Em) of these four rice cultivars were significantly different when exposed to low external NO3- (<1 mmol/L); while they were very similar at high external NO3- (10 mmol/L). The root cell membrane potentials of YD and XY63 were more responsive to low external NO3- than those of NK and SY917. The△Em values for YD and XY63 rhizodermal cells were almost the same at both 0.1 mmol/L and 1 mmol/L NO3-; while for the NK and SY917 the values became larger as the external NO3- increased. For YD cultivar,△Em was measured over a range of NO3- concentrations and a Michaelis-Menten fit to the data gave a Km value of 0.17 mmol/L. Net NO3- uptake depletion kinetics were also compared and for some cultivars (YD and XY63) a single-phase uptake system with first order kinetics best fitted the data; while other cultivars (ND and SY917) showed a better fit to two uptake systems. These uptake systems had two affinity ranges: one had a similar Km in all the cultivars (0.2 mmol/L); the other much higher affinity system (0.03 mmol/L) was only present in NK and SY917. The expression pattern of twelve different NO3- transporter genes was tested using specific primers, but only OsNRT1.1 and OsNRT2.1 expression could be detected showing significant differences between the four rice cultivars. The results from both the physiological and molecular experiments do provide some support for the hypothesis that the more popular rice cultivars grown in Jiangsu Province may be better at using NO3- as an N source.     

Rapid evolution of immunoglobulin superfamily C2 domains expressed in immune system cells

To test the hypothesis that proteins expressed in cells of the vertebrate immune system evolve unusually rapidly, 107 orthologous immunoglobulin C2 domains were compared between human and murine rodent. The analysis showed that the rate of nonsynonymous (amino-acid- altering) nucleotide substitution in these domains was correlated with factors associated with protein structure and with breadth of tissue expression, as well as with the rate of synonymous substitution. However, when such factors were controlled for statistically, there remained a strong positive association between expression in the immune system and nonsynonymous rate, with the highest rates being seen in genes expressed in the immune system only. Certain immune system genes are known to be subject to positive selection favoring diversity at the amino acid level; most of these genes encode receptors that interact directly with foreign antigens. The observed acceleration of the rate of nonsynonymous evolution in C2 domains of immune system proteins may be explained by either (1) reduced constraint at the amino acid level on molecules interacting with immune system receptors that are themselves evolving rapidly due to positive diversifying selection or (2) positive selection favoring amino acid changes correlated with changes in the immune system receptors.      

Cell surface distribution and intracellular fate of asialoglycoproteins: a morphological and biochemical study of isolated rat hepatocytes and monolayer cultures

A combination of biochemistry and morphology was used to demonstrate that more than 95 percent of the isolated rat hepatocytes prepared by collagenase dissociation of rat livers retained the pathway for receptor-mediated endocytosis of asialoglycoproteins (ASGPs). Maximal specific binding of (125)I-asialoorosomucoid ((125)I-ASOR) to dissociated hepatocytes at 5 degrees C (at which temperature no internalization occurred) averaged 100,000-400,000 molecules per cell. Binding, uptake, and degredation of (125)I- ASOR at 37 degrees C occurred at a rate of 1 x 10(6) molecules per cell over 2 h. Light and electron microscopic autoradiography (LM- and EM-ARG) of (125)I-ASOR were used to visualize the surface binding sites at 5 degrees C and the intracellular pathway at 37 degrees C. In the EM-ARG experiments, ARG grains corresponding to (125)I-ASOR were distributed randomly over the cell surface at 5 degrees C but over time at 37 degrees C were concentrated in the lysosome region. Cytochemical detection of an ASOR-horseradish peroxidase conjugate (ASOR-HRP) at the ultrastructural level revealed that at 5 degrees C this specific ASGP tracer was concentrated in pits at the cell surface as well as diffusely distributed along the rest of the plasma membrane. Such a result indicates that redistribution of ASGP surface receptors had occurred. Because the number of surface binding sites of (125)I-ASOR varied among cell preparations, the effect of collagenase on (125)I-ASOR binding was examined. When collagenase-dissociated hepatocytes were re-exposed to collagenase at 37 degrees C, 10-50 percent of control binding was observed. However, by measuring the extent of (125)I-ASOR binding at 5 degrees C in the same cell population before and after collagenase dissociation, little reduction in the number of ASGP surface receptors was found. Therefore, the possibility that the time and temperature of the cell isolations allowed recovery of cell surface receptors following collagenase exposure was tested. Freshly isolated cells, dissociated cells that were re-exposed to collagenase, and perfused livers exposed to collagenase without a Ca(++)-free pre-perfusion, were found to bind 110-240 percent more(125)I-ASOR after 1 h at 37 degrees C that they did at 0 time. This recovery of surface ASGP binding activity occurred in the absence of significant protein synthesis (i.e., basal medium or 1 mM cycloheximide). Suspensions of isolated, unpolarized hepatocytes were placed in monolayer culture for 24 h and confluent cells were demonstrated to reestablish morphologically distinct plasma membrane regions analogous to bile canalicular, lateral, and sinusoidal surfaces in vivo. More than 95 percent of these cells maintained the capacity to bind, internalize, and degrade (125)I-ASOR at levels comparable to those of the freshly isolated population. ASOR-HRP (at 5 degrees C) was specifically bound to all plasma membrane surfaces of repolarized hepatocytes (cultured for 24 h) except those lining bile canalicular-like spaces. Thus, both isolated, unpolarized hepatocytes and cells cultured under conditions that promote morphological reestablishment of polarity maintain the pathway for receptor- mediated endocytosis of ASGPs.     

Molecular phylogeny of the Pooideae (Poaceae) based on nuclear rDNA (ITS) sequences

Phylogenetic relationships of the Poaceae subfamily, Pooideae, were estimated from the sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. The entire ITS region of 25 species belonging to 19 genera representing seven tribes was directly sequenced from polymerase chain reaction (PCR)-amplified DNA fragments. The published sequence of rice, Oryza saliva, was used as the outgroup. Sequences of these taxa were analyzed with maximum parsimony (PAUP) and the neighbor-joining distance method (NJ). Among the tribes, the Stipeae, Meliceae and Brachypodieae, all with small chromosomes and a basic number more than x=7, diverged in succession. The Poeae, Aveneae, Bromeae and Triticeae, with large chromosomes and a basic number of x=7, form a monophyletic clade. The Poeae and Aveneae are the sister group of the Bromeae and Triticeae. On the ITS tree, the Brachypodieae is distantly related to the Triticeae and Bromeae, which differs from the phylogenies based on restriction-site variation of cpDNA and morphological characters. The phylogenetic relationships of the seven pooid tribes inferred from the ITS sequences are highly concordant with the cytogenetic evidence that the reduction in chromosome number and the increase in chromosome size evolved only once in the pooids and pre-dated the divergence of the Poeae, Aveneae, Bromeae and Triticeae.This paper reports factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitableThis paper is a cooperative investigation of USDA-ARS and the Utah Agricultural Experiment Station. Logan, Utah 84322. Journal Paper No. 4581     

Global expression analysis of nucleotide binding site-leucine rich repeat-encoding and related genes in Arabidopsis

Background  

Nucleotide binding site-leucine rich repeat (NBS-LRR)-encoding genes comprise the largest class of plant disease resistance genes. The 149 NBS-LRR-encoding genes and the 58 related genes that do not encode LRRs represent approximately 0.8% of all ORFs so far annotated in Arabidopsis ecotype Col-0. Despite their prevalence in the genome and functional importance, there was little information regarding expression of these genes.     

Isolation and characterization of microsatellite loci in the sand fly Phlebotomus papatasi (Diptera: Psychodidae)

Phlebotomus papatasi is a proven vector of Leishmania major which is one of the causative agents of cutaneous leishmaniasis in the Old World. Although it has a wide geographical range, its population structure is not yet well understood. In an effort to better understand the population dynamics of this vector, we developed a panel of di‐ and trinucleotide microsatellite markers, using a magnetic bead hybridization enrichment protocol. These microsatellite loci showed three to seven alleles with an expected heterozygosity range between 0.702 and 0.876. The level of polymorphisms found in this study suggests that these microsatellite loci can be used for population analysis of P. papatasi.     

INCITE: A randomised trial comparing constraint induced movement therapy and bimanual training in children with congenital hemiplegia

Background  

Congenital hemiplegia is the most common form of cerebral palsy (CP) accounting for 1 in 1300 live births. These children have limitations in capacity to use the impaired upper limb and bimanual coordination deficits which impact on daily activities and participation in home, school and community life. There are currently two diverse intensive therapy approaches. Traditional therapy has adopted a bimanual approach (BIM training) and recently, constraint induced movement therapy (CIMT) has emerged as a promising unimanual approach. Uncertainty remains about the efficacy of these interventions and characteristics of best responders. This study aims to compare the efficacy of CIMT to BIM training to improve outcomes across the ICF for school children with congenital hemiplegia.