Sample entropy analysis of pupillary signals in glaucoma patients and control via light-induced pupillometry.

This paper evaluated the pupillary light reflex of glaucomatous eyes in the presence of constant lighting via light-induced pupillometry using sample entropy. The study used 20 patients and 15 controls, applied three different light intensities to their eyes, and recorded the behavior of the pupil. This study has validated that there is a difference in the entropy of pupillary data in glaucoma and healthy eyes. We concluded that entropy analysis is an excellent method to differentiate glaucoma eyes with the control through light-induced pupillometry. Hence, pupillometry has potential clinical applications in glaucoma investigation.

Detection of Functional Deterioration in Glaucoma by Trend Analysis Using Overlapping Clusters of Locations.

Purpose: Cluster trend analysis detects glaucomatous deterioration within predefined subsets (clusters) of visual field locations. However, it may miss small defects straddling boundaries between the clusters. This study assesses whether simultaneously using a second set of clusters, overlapping the first, could improve progression detection. Methods: Deterioration in eyes with or at risk of glaucomatous visual field loss was "detected" by mean deviation (MD) on the first visit at which the P value from linear regression over time was below the fifth percentile of its permutation distribution. Similarly, P values were calculated for each of 10 predefined nonoverlapping clusters of locations, or 21 overlapping clusters; deterioration was "detected" when the Nth-smallest P value was below the fifth percentile of its permutation distribution, for different N. Times to detect deterioration were compared using survival models. Results: Biannual series of ≥5 visual fields (mean = 14) were available for 420 eyes of 213 participants. Deterioration of 33% of eyes was detected earliest using N = 1 overlapping cluster in 3.3 years (95% confidence interval 2.7-4.6 years); or N = 2 nonoverlapping clusters in 3.3 years (2.7-5.0) (comparison P = 0.654). There was also no significant difference in the probability that deterioration would be confirmed (92.8% vs. 94.4%, P = 0.289). Both overlapping and nonoverlapping clusters detected deterioration significantly sooner than MD (4.5 years, P ≤ 0.001). Conclusions: After equalizing specificity, overlapping clusters of locations did not significantly reduce the time to detect deterioration compared with nonoverlapping clusters. Translational Relevance: Cluster trend analyses detected deterioration sooner than global analyses even when defects straddled cluster borders.

Decellularizing the Porcine Optic Nerve Head: Toward a Model to Study the Mechanobiology of Glaucoma.

Purpose: Studying the extracellular matrix (ECM) remodeling of the lamina cribrosa in vivo can be extremely challenging and costly. There exist very few options for studying optic nerve head (ONH) mechanobiology in vitro that are able to reproduce the complex anatomic and biomechanical environment of the ONH. Herein, we have developed a decellularization procedure that will enable more anatomically relevant and cost-efficient future studies of ECM remodeling of the ONH. Methods: Porcine posterior poles were decellularized using a detergent and enzyme-based decellularization protocol. DNA quantification and histology were used to investigate the effectiveness of the protocol. We subsequently investigated the ability of a polyethylene glycol (PEG)-based hydrogel to restore the ONH's ability to hold pressure following decellularization. Anterior-posterior displacement of the decellularized and PEG treated ONH in a pressure bioreactor was used to evaluate the biomechanical response of the ONH. Results: DNA quantification and histology confirmed decellularization using Triton X-100 at low concentration for 48 hours successfully reduced the cellular content of the tissue by 94.9% compared with native tissue while preserving the ECM microstructure and basal lamina of the matrix. Infiltrating the decellularized tissues with PEG 6000 and PEG 10,000 hydrogel restored their ability to hold pressure, producing displacements similar to those measured for the non-decellularized control samples. Conclusions: Our decellularized ONH model is capable of producing scaffolds that are cell-free and maintain the native ECM microstructure. Translational Relevance: This model represents a platform to study the mechanobiology in the ONH and potentially for glaucoma drug testing.

The daily, monthly, and annual cost of glaucoma therapy using ocular hypotensive eye drops in the Philippines based on a quantitative method

@#OBJECTIVE: This study aimed to calculate and compare the costs of different brands of ocular hypotensive eye drops available in the Philippines. METHODS: This was a single-center research conducted at a local laboratory. Triplicate samples of 21 different brands of locally-available ocular hypotensive drops were tested. The mass of ten drops, total usable mass, number of drops per bottle, and mass of 200-µL aliquots were measured for each sample. These were used to calculate for the total usable bottle volume, drop volume, and number of drops per milliliter of each sample. Lastly, the daily, monthly, and annual costs were computed and compared. RESULTS: Available brands of β-blockers were the most affordable options for topical glaucoma therapy, with costs ranging from Php1,838 to 8,472 per year. Innovator brands of α-agonists and carbonic anhydrase inhibitors were the most expensive, with annual costs ranging from Php7,641 to 24,295 and Php7,361 to 25,327, respectively. Fixed-combination preparations, with yearly costs ranging from Php4,307 to 22,200, were generally more costeffective than individual preparations. The cost of topical anti-glaucoma therapy can amount up to 3.3 to 66.9% of a minimum-wage earner’s annual income depending on the number and combination of drugs being used. CONCLUSIONS: The price range of ocular hypotensive eye drops available in the Philippines is wide. Cost of therapy is an important consideration for patients who acquire medications through out-of-pocket expenditure. Optimization of bottle designs and volumes is crucial to maximize the cost-effectiveness of eye drop solutions. Information on the cost of therapy should be available to both patients and physicians.

Survey of glaucoma practice patterns among members of The Philippine Glaucoma Society

@#OBJECTIVE: To identify the glaucoma clinical practice patterns among the members of the Philippine Glaucoma Society (PGS) from 2015 to 2016 using an online survey. METHODS: An online link was sent to each consenting PGS member which directed them to two poll sites. These sites asked questions about demographics and their preferred clinical practice patterns. Frequency and percent distributions were used to analyze the data. RESULTS: There was a high response rate from PGS members at 97% (42 out of 43 members). More than half of respondents (51%, n=22) defined glaucoma as glaucomatous optic neuropathy with an evident visual field loss. IOP was routinely measured by 90% (n=38) of the respondents with majority preferring to use the Goldmann applanation tonometer (GAT) (98%, n=41). Gonioscopy was done on all new patients by all PGS members but only 62% did regular gonioscopy on follow-up consultations. Most of the respondents relied on the 90D lens (88%) to assess the optic nerve. Visual field examination (VFE) was routinely requested by all respondents. Pachymetry and anterior segment optical coherence tomography (AS-OCT) were used sparingly at only 43% and 12% respectively. Appositional angle closure was addressed by performing laser iridotomy with majority of the respondents preferring a site that is covered by the upper eyelid (57%). Prostaglandin analogues were the top choice as first-line monotherapy for eyes with open-angle glaucoma. Majority of the respondents (55%) opted to do laser trabeculoplasty (LTP) as an adjunct to medical therapy. Mitomycin-C was the preferred intraoperative antimetabolite for trabeculectomy by 98% (n=41). Ahmed (71%, n=30) was the more favored glaucoma drainage device (GDD) by our respondents over Baerveldt (19%, n=8). CONCLUSION: This survey showed majority of the glaucoma practices of PGS members appear to adhere to the current clinical practice guidelines.

Barcodes Reveal 48 New Species of Tetrahymena, Dexiostoma, and Glaucoma: Phylogeny, Ecology, and Biogeography of New and Established Species.

Tetrahymena mitochondrial cox1 barcodes and nuclear SSUrRNA sequences are particularly effective at distinguishing among its many cryptic species. In a project to learn more about Tetrahymena natural history, the majority of >1,000 Tetrahymena-like fresh water isolates were assigned to established Tetrahymena species with the remaining assigned to 37 new species of Tetrahymena, nine new species of Dexiostoma and 12 new species of Glaucoma. Phylogenetically, all but three Tetrahymena species belong to the well-established "australis" or "borealis" clades; the minority forms a divergent "paravorax" clade. Most Tetrahymena species are micronucleate, but others are exclusively amicronucleate. The self-splicing intron of the LSUrRNA precursor is absent in Dexiostoma and Glaucoma and was likely acquired subsequent to the "australis/borealis" split; in some instances, its sequence is diagnostic of species. Tetrahymena americanis, T. elliotti, T. gruchyi n. sp., and T. borealis, together accounted for >50% of isolates, consistent with previous findings for established species. The biogeographic range of species found previously in Austria, China, and Pakistan was extended to the Nearctic; some species show evidence of population structure consistent with endemism. Most species were most frequently collected from ponds or lakes, while others, particularly Dexiostoma species, were collected most often from streams or rivers. The results suggest that perhaps hundreds of species remain to be discovered, particularly if collecting is global and includes hosts of parasitic forms.

Did Gause Have a Yeast Infection?

We planned to develop predator-prey models using Paramecium and yeast, but they have not been empirically examined since work by Gause in the 1930s. Therefore, we evaluated if Paramecium aurelia ingests and grows on eight yeasts. Recognising that it ingested yeasts but could not grow, we assessed if it might grow on other yeasts, by empirically parameterising a predator-prey model that relies on ingestion, not growth. Simulations were compared to P. aurelia-yeast time-series data, from Gause. We hypothesised that if the model simulated predator-prey dynamics that mimicked the original data, then possibly P. aurelia could grow on yeast; simulations did not mimic the original data. Reviewing works by Gause exposed two issues: experiments were undoubtedly contaminated with bacteria, allowing growth on bacteria, not yeast; and the population cycle data cannot be considered a self-sustaining time series, as they were manipulated by adding yeast and ciliates. We conclude that past and future work should not rely on this system, for either empirical or theoretical evaluations. Finally, although we show that P. aurelia, P. caudatum, Euplotes patella, and Blepharisma sp. cannot grow on yeast, Tetrahymena pyriformis and Colpidium striatum can; these may provide models to explore predator-prey dynamics.

“VisualFields Easy”: an iPad application as a simple tool for detecting visual field defects

@#<p style="text-align: justify;"><strong>PURPOSE/OBJECTIVE:</strong> This study aims to determine the reliability of the "VisualFields Easy" application in detecting visual field loss among ophthalmology patients; and to determine the sensitivity, specificity, positive predictive and negative predictive values of this examination using the Humphrey Visual Field Analyzer as the gold standard.</p> <p style="text-align: justify;"><strong>METHODS:</strong> This is an analytical study that enrolled subjects requiring visual field examination as part of the comprehensive evaluation of their ophthalmologic condition. Each subject was tested using the standard automated Humphrey Field Analyzer (Carl Zeiss Meditec, Inc., Germany) with the 30-2 Swedish Interactive Thresholding Algorithm (SITA) and the "VisualFields Easy" application (background = 10 cd / m2 ; size V target; 16-dB stimulus) loaded in an iPad 2 ver. 8.3. The print outs of each test were then interpreted independently by the principal investigator and verified by a glaucoma specialist as positive or negative for visual field defects and computation for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were done.</p> <p style="text-align: justify;"><strong>RESULTS:</strong> The study included 137 eyes of 77 patients, 52 (68%) females and 25 (32%) males, age ranging from 18 to 82 years with a mean (SD) of 58 (+ 14) years. The mean test duration for the standard Humphrey perimetry was 7 minutes 50 seconds (SD + 0.08s), and 3 minutes 21 seconds (SD + 0.01s) for the "VisualFields Easy". Correlations of False Positives and False Negatives between the 2 tests were p=0.02 and p=0.03 respectively and that there was no statistically significant difference between the reliability parameters of the two tests. There were a total of 74 positives and 63 negatives visual field defects for the Humphrey. These were considered as the True Positive (TP) and True Negative (TN) values. For the "VisualFields Easy", there were 67 positives and 70 negatives. The results of the "VisualFields Easy" were plotted against the Humphrey perimetry. Sensitivity was computed at 91% and specificity at 100%. Likewise the Positive Predictive Value (PPV) was computed to be 100% and the Negative Predictive Value (NPV) was computed at 90%.</p> <p style="text-align: justify;"><strong>CONCLUSION:</strong> The "VisualFields Easy" application is a quick, easily accessible and fairly reliable way of measuring visual field abnormalities, both for glaucoma and neuro-ophthalmology patients. The application is not intended to replace standard automated perimetry machines, but it may have a role in detecting, documenting and monitoring visual field defects in low resource settings where visual field tests are not available.</p>

Clinical profile and demographics of glaucoma patients managed in a Philippine tertiary hospital

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To determine the demographic and clinical profile of glaucoma patients seen in a Philippine tertiary hospital from 2011 to 2014.<br /><br /><strong>METHOD:</strong> Medical records of glaucoma patients managed at the outpatient ophthalmology clinic from October 2010 to August 2014 were reviewed. Diagnosis of glaucoma was based on the International Society of Geographic and Epidemiological Ophthalmology (ISGEO) guidelines. The demographics, clinical profile, functional severity scoring, and initial management of patients were described.<br /><br /><strong>RESULT:</strong> Majority of the 570 patients were females (60.17%), with a mean age of 56.23 years. Eighty-five percent claimed to have no family history of glaucoma. The mean best-corrected visual acuity (BCVA) was 0.40, the mean intraocular pressure (IOP) was 23.56 mmHg, and the mean cup-to-disc (CD) ratio was 0.69. There were more primary type of glaucoma (55.48%) than secondary glaucoma. Mixed pattern was the most common type of visual field pattern at initial presentation. Majority of the defects were under GSS 2 stage 2 of mean deviation (MD) and loss variance (LV). Medical treatment was the most common initial management given to glaucoma patients.<br /><br /><strong>CONCLUSION:</strong> The primary glaucomas were more common than the secondary glaucomas seen in a private tertiary hospital. Most had moderate visual field damage (mixed type pattern) and the most common initial management given was medical treatment.<br /><br /><strong>KEYWORD:</strong> Glaucoma, Epidemiology, Primary open angle glaucoma, Primary angle closure glaucoma, Secondary glaucoma, Normal tension glaucoma, ISGEO guidelines</p>

Correlation between average retinal nerve fiber layer thickness and rim area of the spectral-domain OCT with the Humphrey visual field index in eyes with glaucoma

@#<p style="text-align: justify;"><strong>OBJECTIVE:</strong> To determine the correlation between the average retinal nerve fiber layer (RNFL) thickness and optic nerve head rim area (RA) measured with a spectral-domain optical coherence tomography (OCT) with the visual field index (VFI) using the Humphrey Visual Field Analyzer in glaucoma patients.<br /><strong>METHODS:</strong> Eighty-five consecutive patients diagnosed with glaucoma underwent spectral-domain OCT of the optic disc and Humphrey perimetry. A glaucoma specialist confirmed the presence of glaucomatous optic neuropathy based on findings in the optic nerve head photographs, OCT measurements of the RNFL and optic disc, and standard automated perimetry. The correlation of the average RNFL thickness and rim area with the VFI was determined using the Spearman's correlation coefficient analysis.<br /><strong>RESULTS:</strong> A total of 121 glaucomatous eyes of 85 patients were included in the study. There were 47 males and 38 females, ages ranging from 12 to 94 years. The average RNFL thickness, RA, and VFI were 67.9 ± 12.3 ?m, 0.65 ± 0.3 mm2, and 56 ± 32%, respectively. The average RNFL thickness (r = 0.35) showed a stronger positive correlation with VFI than RA (r = 0.15), but the difference was not statistically significant.<br /><strong>CONCLUSION:</strong> The average RNFL thickness and rim area of the spectral-domain OCT demonstrated a positive correlation with the VFI of the Humphrey Visual Field Analyzer. The OCT parameters, exemplified by average RNFL and RA, were not good indicators for VFI.</p>

Functional ecology of the ciliate Glaucomides bromelicola, and comparison with the sympatric species Bromeliothrix metopoides.

We investigated the ecology and life strategy of Glaucomides bromelicola (family Bromeliophryidae), a very common ciliate in the reservoirs (tanks) of bromeliads, assessing its response to food quality and quantity and pH. Further, we conducted competition experiments with the frequently coexisting species Bromeliothrix metopoides (family Colpodidae). In contrast to B. metopoides and many other colpodean ciliates, G. bromelicola does not form resting cysts, which jeopardizes this ciliate when its small aquatic habitats dry out. Both species form bactivorous microstomes and flagellate-feeding macrostomes. However, only G. bromelicola has a low feeding threshold and is able to adapt to different protist food. The higher affinity to the local bacterial and flagellate food renders it the superior competitor relative to B. metopoides. Continuous encystment and excystment of the latter may enable stable coexistence of both species in their natural habitat. Both are tolerant to a wide range of pH (4-9). These ciliates appear to be limited to tank bromeliads because they either lack resting cysts and vectors for long distance dispersal (G. bromelicola) and/or have highly specific food requirements (primarily B. metopoides).

Description of Glaucomides bromelicola n. gen., n. sp. (Ciliophora, Tetrahymenida), a macrostome forming inhabitant of bromeliads (Bromeliaceae), including redescriptions of Glaucoma scintillans and G. reniformis.

Glaucomides bromelicola n. gen., n. sp. is a tetrahymenid ciliate common in tank bromeliads of Central and South America. The new genus is characterized by having a kinety fragment along the left mouth margin, an unciliated dorsolateral area, a tetrahymenid silverline pattern, and the ability to produce macrostomes when bacterial food is depleted. I provide a detailed description of the microstome and the macrostome morph, using several morphological methods. This showed that G. bromelicola does not belong to the Glaucomidae, but to the Bromeliophryidae. However, various morphological traits are highly similar to those of Glaucoma reniformis and G. scintillans, which are thus redescribed and compared with G. bromelicola. Most differences are inconspicuous, showing that new tetrahymenids must be described very carefully. The morphological and molecular data suggest a common ancestor for Glaucoma and Glaucomides, both performing their own radiation, the former in ordinary limnetic habitats, the latter in tank bromeliads.

Ingredients for protist coexistence: competition, endosymbiosis and a pinch of biochemical interactions.

1. The interaction between mutualism, facilitation or interference and exploitation competition is of major interest as it may govern species coexistence. However, the interplay of these mechanisms has received little attention. This issue dates back to Gause, who experimentally explored competition using protists as a model [Gause, G.F. (1935) Vérifications expérimentales de la théorie mathématique de la lutte pour la vie. Actualités Scientifiques et Industrielles, 277]. He showed the coexistence of Paramecium caudatum with a potentially allelopathic species, Paramecium bursaria. 2. Paramecium bursaria hosts the green algae Chlorella vulgaris. Therefore, P. bursaria may benefit from carbohydrates synthesised by the algae. Studying endosymbiosis with P. bursaria is possible as it can be freed of its endosymbiont. In addition, C. vulgaris is known to produce allelochemicals, and P. bursaria may benefit also from allelopathic compounds. 3. We designed an experiment to separate the effects of resource exploitation, endosymbiosis and allelopathy and to assess their relative importance for the coexistence of P. bursaria with a competitor that exploits the same resource, bacteria. The experiment was repeated with two competitors, Colpidium striatum or Tetrahymena pyriformis. 4. Results show that the presence of the endosymbiont enables the coexistence of competitors, while its loss leads to competitive exclusion. These results are in agreement with predictions based on resource equilibrium density of monocultures (R*) supporting the idea that P. bursaria's endosymbiont is a resource provider for its host. When P. bursaria and T. pyriformis coexist, the density of the latter shows large variation that match the effects of culture medium of P. bursaria. Our experiment suggests these effects are because of biochemicals produced in P. bursaria culture. 5. Our results expose the hidden diversity of mechanisms that underlie competitive interactions. They thus support Gauses's speculation (1935) that allelopathic effects might have been involved in his competition experiments. We discuss how a species engaged both in competition for a resource and in costly interference such as allelopathy may counterbalance these costs with a resource-provider endosymbiont.

Alternative community compositional and dynamical states: the dual consequences of assembly history.

1. Much work on ecological consequences of community assembly history has focused on the formation of history-induced alternative stable equilibria. We hypothesize that assembly history may affect not only community composition but also population dynamics, with assembled communities differing in species composition potentially residing in different dynamical states. 2. We provided an empirical test of the aforementioned hypothesis using a laboratory microcosm experiment that manipulated both the colonization order of three bacterivorous protist species in the presence of a protist predator and environmental productivity. 3. Both priority effects and random divergence emerged, resulting in two different community compositional states: one characterized by the dominance of one prey species and the other by the extinction of the same prey. While communities in the former state exhibited noncyclic dynamics, the majority of communities in the latter state exhibited cyclic dynamics driven by the interaction between another prey and the predator. 4. Temporal variability of total prey community biovolume consequently differed among communities with different histories. 5. Changing productivity altered priority effects on the structure and dynamics of communities experiencing only certain histories. 6. Our results support the dual (compositional and dynamical) consequences of assembly history and emphasize the importance of incorporating the dynamical view into the field of community assembly.

[Ultrastructural changes of the trabecular meshwork in glucocorticoid induced glaucoma].

PURPOSE: Steroid-induced glaucoma in rabbit ocular was established to observe the ultrastructural changes in trabecular meshwork,and to preliminarily study the mechanisms of increased resistance of aqueous outflow in steroid-induced glaucoma. METHODS: Forty New Zealand white rabbits were randomly divided into four groups, namely,control group (n = 10 rats),drops drug group(n = 10 rats), Injecting drug group(n = 10 rats) and drug combination group (n=10 rats). For three consecutive days before the experiment,using the Schitoz's tonometer to measure intraocular pressure(IOP) at 8am, 10am, and 12am each day,obtained the average,and finally calculated basis IOP of these rabbits. The rabbits eyes in drug combination group of were treated with dexamethasone sodium phosphate solution (0.5%)for 8 weeks,three times a day, and given injection of triamcinolone endure (3 mg) weekly. While the rabbits eyes in the control group were treated with sterile saline in the same period of experiment.After 4 days,IOP of the rabbit was measured by Schitoz's tonometer weekly( the IOP was measured at 8am, 10am, 12am each day for the average value).The rabbit whose IOP was more than 21.97 mmHg and continued for one week is regarded a successful animal model as Corticosteroid. After 8 weeks,the eyes of control group and Corticosteroid rabbits was made for Transmission electron microscopy(TEM) specimen which was used to study the ultrastructural of trabecular meshwork cell. RESULTS: 1.The Rabbit-based IOP was (18.082±2.398) mmHg（n=80）,in the drug combination group The IOP of rabbit is up to (24.056±1.245) mmHg after three weeks，which was significantly higher compared with that of(18.254 ± 3.465) mmHg in the control group,the difference had significance(p<0.05),after six weeks, which reached the peak, up to (30.214±0.766) mmHg,in the eighth week, up to (29.144±0.685) mmHg, the IOP of 16 rabbit eyes from 20 rabbit eyes in the exprimental group increased.The positive rate was 80%.2. After treatment with dexamethasone,the abnormality of nucleus of the trabecular meshwork cell was increased, microfilament and microtubules among interstitial cells also increased ,cytoplasmic vacuolation, rough endoplasmic reticulum expansion, as well as an increase in intercellular amorphous material. CONCLUSION: 1.The glucocorticoid-induced high intraocular pressure rabbit model has been successfully established in drug combination group.2.A series of changes in the cytoskeleton observed under the transmission electron microscopy are an important part of glucocorticoid-induced elevation of intraocular pressure.

Vertical oviposition and Lambornella clarki (Ciliophora: Tetrahymenidae) dispersal by Aedes sierrensis (Diptera: Culicidae) in California.

Vertical stratification of treeholes used by mosquitoes may reflect resource quality or result from interspecific competition. Mosquitoes able to monopolize treeholes with optimal resources may be over-represented in the community. Aedes sierrensis, which is well adapted for the Mediterranean climate of California, has evolved in the absence of interspecific competition, so oviposition should reflect resource quality to a large extent. Artificial oviposition traps mounted at four canopy heights facing north or south on trees in a mixed-oak forest at four elevations of the Pacific Coastal Range were used to assess vertical ovipositional preferences by the western treehole mosquito. Natural dispersal of the ciliated protozoan parasite Lambornella clarki was similarly monitored. Gravid Ae. sierrensis showed no vertical stratification during egg laying in traps. Lambornella clarki were naturally dispersed at relatively low frequency into traps and persisted unless eliminated by larval predation. Aedes sierrensis is not currently constrained into occupying a subset of treeholes. However, invasion of its native range by competitive species may alter oviposition patterns.

Agolohymena aspidocauda nov. gen., nov. spec., a histophagous freshwater tetrahymenid ciliate in the family Deltopylidae (Ciliophora, Hymenostomatia), from Idaho (northwest USA): morphology, ontogenesis and molecular phylogeny.

Morphology, ontogeny and the molecular phylogeny of Agolohymena aspidocauda nov. gen., nov. spec., a new freshwater tetrahymenid ciliate from Idaho, U.S.A, are described. The ontogeny and histophagous mode of nutrition are similar to those of Deltopylum rhabdoidesFauré-Fremiet and Mugard, 1946. The new genus is placed with Deltopylum in the resurrected family Deltopylidae Song and Wilbert, 1989. We emend the diagnostic features of the family to include division by polytomy, right and left somatic kineties extending into the preoral suture, crook-shaped or sigmoid adoral membranelles 1 and 2, markedly reduced adoral membranelle 3 and a tetrahymenid silverline pattern. The main diagnostic features of the new genus are a disc-shaped caudal ciliary array and formation of two types of resting cysts, one smooth and the other bearing tangled tubular or cylindrical lepidosomes. Nuclear small subunit ribosomal RNA gene and mitochondrial cytochrome oxidase subunit 1 gene sequences place the new genus basal within the order Tetrahymenida, well separated from members of the family Tetrahymenidae (Lambornella and Tetrahymena) and also from other tetrahymenids (Colpidium, Dexiostoma, Glaucoma). The genetic divergences between this species and other genera in Tetrahymenida are large enough to suggest placement of the new genus in a separate family. This corroborates the morphological data, since the elaborate caudal ciliary array and the lepidosome-covered resting cyst of this species are not found in other Tetrahymenidae.

Predation alters relationships between biodiversity and temporal stability.

Abstract: Ecologists disagree on how diversity affects stability. At the heart of the controversy is the relationship between diversity and population stability, with conflicting findings from both theoretical and empirical studies. To help reconcile these results, we propose that this relationship may depend on trophic complexity, such that positive relations tend to emerge in multitrophic but not single-trophic communities. This hypothesis is based on the premise that stabilizing weak trophic interactions restrain population oscillations associated with strong trophic interactions in diverse multitrophic communities. We tested this hypothesis using simple freshwater bacterivorous protist communities differing in diversity with and without a predatory protist species. Coupling weak and strong trophic interactions reduced population temporal variability of the strong-interacting species, supporting the stabilizing role of weak interactions. In keeping with our hypothesis, predation altered the overall effect of diversity on population temporal stability and, in particular, caused a reversal of the diversity-stability relationship (negative without predators and positive with predators) for the strong-interacting species. A similar role of predation was also observed when examining the relationship between diversity and temporal stability of community biomass. Together, these findings demonstrated strong interactive effects of trophic interactions and diversity on temporal stability of population and community properties.

Barcoding ciliates: a comprehensive study of 75 isolates of the genus Tetrahymena.

The mitochondrial cytochrome-c oxidase subunit 1 (cox1) gene has been proposed as a DNA barcode to identify animal species. To test the applicability of the cox1 gene in identifying ciliates, 75 isolates of the genus Tetrahymena and three non-Tetrahymena ciliates that are close relatives of Tetrahymena, Colpidium campylum, Colpidium colpoda and Glaucoma chattoni, were selected. All tetrahymenines of unproblematic species could be identified to the species level using 689 bp of the cox1 sequence, with about 11 % interspecific sequence divergence. Intraspecific isolates of Tetrahymena borealis, Tetrahymena lwoffi, Tetrahymena patula and Tetrahymena thermophila could be identified by their cox1 sequences, showing <0.65 % intraspecific sequence divergence. In addition, isolates of these species were clustered together on a cox1 neighbour-joining (NJ) tree. However, strains identified as Tetrahymena pyriformis and Tetrahymena tropicalis showed high intraspecific sequence divergence values of 5.01 and 9.07 %, respectively, and did not cluster together on a cox1 NJ tree. This may indicate the presence of cryptic species. The mean interspecific sequence divergence of Tetrahymena was about 11 times greater than the mean intraspecific sequence divergence, and this increased to 58 times when all isolates of species with high intraspecific sequence divergence were excluded. This result is similar to DNA barcoding studies on animals, indicating that congeneric sequence divergences are an order of magnitude greater than conspecific sequence divergences. Our analysis also demonstrated low sequence divergences of <1.0 % between some isolates of T. pyriformis and Tetrahymena setosa on the one hand and some isolates of Tetrahymena furgasoni and T. lwoffi on the other, suggesting that the latter species in each pair is a junior synonym of the former. Overall, our study demonstrates the feasibility of using the mitochondrial cox1 gene as a taxonomic marker for 'barcoding' and identifying Tetrahymena species and some other ciliated protists.