Hantzschia subandina Frenguelli (Bacillariophyceae): Morfología, status y tipificación, asi como la descripción de una nueva especie de Nitzschia

Background and aims: Hantzschia Grunow is a genus characterized by having valves asymmetric to the apical axis, markedly dorsiventral, with an eccentric raphe on the ventral side supported by fibulae and ‘hantzschioid’ symmetry of the frustules. In 1942 J. Frenguelli published the flora of diatoms of Neuquén province (Argentina), work in which he erected Hantzschia subandina as a new species for science. This work investigates the identity and taxonomic status of this taxon. M&M: Original material of Hantzschia subandina of the Frenguelli Collection was analysed with light and scanning electron microscopy. Results and Conclusions: Observations on the material suggested two different species were included in the concept of this species assigned originally to the genus Hantzschia. Furthermore, neither of the two species present are assignable to the genus Hantzschia. Nitzschia subandina (Frenguelli) comb. nov. has a large central nodule and a slight asymmetry about the apical axis; it also produces frustules with nitzschioid and hantzschioid symmetry. We designate a lectotype for this taxon. In addition, another diatom in the same material with slight asymmetry about the apical axis has distinctive ornamentation on the mantle of the valve and produces nitzschioid and hantzschioid frustules. For this taxon we tentatively assign it to the non-monophyletic genus Nitzschia, describing it as N. araucana sp. nov. We discuss the possible phylogenetic position of this new taxon, and suggest that the genus Nitzschia is “the next Navicula” ready to be further subdivided into distinct genera.Introducción y objetivos: Hantzschia Grunow es un género de diatomeas caracterizado por la asimetría dorsiventral de sus valvas, rafe soportado por fíbulas sobre el margen ventral, y simetría hatzschioide de los frústulos. En 1942 J. Frenguelli publicó la flora de diatomeas de la provincia de Neuquén (Argentina), obra en la que erigió a Hantzschia subandina como una nueva especie para la ciencia. El objetivo de este trabajo es analizar la identidad de este taxón y su status taxonómico. M&M: El material original de Hantzschia subandina, presente en la Colección Frenguelli depositada en el Herbario de la División Ficología del Museo de La Plata, fue analizado con microscopías óptica y electrónica de barrido. Resultados y Conclusiones: la observación del material original de Hantzschia subandina sugiere que dos entidades distintas fueron incluídas en el concepto de esta especie. Ambas producen frústulos tanto con simetría nitzschiode como hantzschioide, por lo que ninguna de ellas pertenece al género Hantzschia. La primera presenta un nódulo central conspicuo y leve asimetría según el eje apical; consideramos que estos ejemplares corresponden a Nitzschia subandina (Frenguelli) comb. nov., y realizamos la enmienda y lectotipificación del taxón. La segunda entidad presente en el mismo material, posee una leve asimetría según el eje apical, y una distintiva ornamentación en el manto valvar; hemos asignado este taxón al género Nitzschia, describiendo N. araucana sp. nov. Discutimos la posible posición filogenética de este nuevo taxón dentro de Nitzschia, género polifilético que requiere de una profunda revisión y subdivisión en géneros, tal como ocurrió con el género Navicula.Facultad de Ciencias Naturales y Muse

Freshwater gomphonemoid diatom phylogeny: preliminary results

A cladistic analysis of eleven freshwater gomphonemoid diatom taxa yielded three equally most parsimonious cladograms. The three cladograms suggest Gomphoneis Cleve is non-monophyletic as originally and recently circumscribed. Gomphoneis elegans and G. transsilvanica (Pant.) Krammer are more closely related to Gomphopleura Reichelt ex Tempère than to other members of the genus. Gomphoneis geitleri Kociolek & Stoermer appears to represent a monotypic lineage. Among the taxa with differentiated apical pore fields Gomphonema kaznakowi Mereschkowsky appears to be primitively astigmate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42885/1/10750_2004_Article_BF00028001.pd

New freshwater diatom genus, Edtheriotia gen. nov. of the Stephanodiscaceae (Bacillariophyta) from south‐central China

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134437/1/pre12145.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134437/2/pre12145_am.pd

SISTEMÁTICA Y DISTRIBUCIÓN DEL GÉNERO LUTICOLA D.G. MANN (BACILLARIOPHYTA) EN ARGENTINA

Los objetivos de mi tesis doctoral son evaluar la riqueza del género de diatomeas Luticola en Argentina, explorar las relaciones filogenéticas del mismo e identificar los patrones de distribución de las especies encontradas en nuestro país. Para ello mi trabajo se centra en cinco brazos principales, estos son la revisión bibliográfica, la consulta de colecciones, el análisis de muestras adquiridas a campo, los análisis moleculares a partir de cultivos unialgales y el desarrollo de mapas de distribución de las especies. Para la revisión bibliográfica analizaré los trabajos en los cuales se citen especies del género en estudio en el país. En cuanto a la consulta de colecciones, principalmente trabajaré con materiales de la Colección de la División Ficología, FCNyM, siendo de especial importancia la Colección de Diatomeas Argentinas Dr. Joaquín Frenguelli, en la cual se encuentran varios materiales tipos del género Luticola. Para la obtención de muestras se realizarán campañas de muestreo a distintas regiones del país. Se tomarán muestras cualitativas (multihábitat) de perifiton, midiendo altitud, coordenadas geográficas y parámetros físicos y químicos del agua. Las muestras colectadas serán conservadas en frío y oscuridad hasta ser llevadas al laboratorio. Parte de estas muestras serán utilizadas para realizar análisis con microscopía óptica y electrónica de barrido y otras para aislamientos y cultivos. Las muestras serán analizadas con microscopio óptico (MO) con contraste de fases e interferencia y microscopio electrónico de barrido (MEB), para esto es necesario eliminar la materia orgánica, lo cual se realizará con peróxido de hidrógeno o peróxido de hidrógeno y dicromato de potasio. El material tratado será montado en Naphrax para su observación con MO y sobre tacos de vidrio y metalizadas con oro para su estudio con MEB. Por otra parte se establecerán cultivos unialgales en medios de cultivo a temperatura y luz controladas. A partir de aquellos cultivos que prosperen se realizará la extracción del ADN y se secuenciaran distintos marcadores que se utilizarán para establecer las relaciones filogenéticas del género. Para establecer los patrones de distribución de las especies se realizará un Análisis de Parsimonia de Endemismos (PAE) basado en localidades. Los resultados de este análisis se compararán con esquemas biogeográficos establecidos a partir de otros grupos de organismos. Los datos biológicos, físicos y químicos serán reunidos en Sistema de Información Geográfica. Los mapas de distribución de las especies se realizarán usando el software QGIS

Systematic and Distribution of Genus Luticola D.G. Mann (Bacillariophyta) in Argentina

Los objetivos de mi tesis doctoral son evaluar la riqueza del género de diatomeas Luticola en Argentina, explorar las relaciones filogenéticas del mismo e identificar los patrones de distribución de las especies encontradas en nuestro país. Para ello mi trabajo se centra en cinco brazos principales, estos son la revisión bibliográfica, la consulta de colecciones, el análisis de muestras adquiridas a campo, los análisis moleculares a partir de cultivos unialgales y el desarrollo de mapas de distribución de las especies. Para la revisión bibliográfica analizaré los trabajos en los cuales se citen especies del género en estudio en el país. Encuanto a la consulta de colecciones, principalmente trabajaré con materiales de la Colección de la División Ficología, FCNyM, siendo de especial importancia la Colección de Diatomeas Argentinas Dr. Joaquín Frenguelli, en la cual se encuentran varios materiales tipos del género Luticola.Universidad Nacional de La Plat

Diatoms from the Shelton Mastodon Site

A fairly diverse and abundant diatom flora is associated with remains of Mammut americanum at the Shelton Mastodon Site in northern Oakland County, Michigan. The most abundant elements of this flora are species commonly recorded from late-glacial deposits in North America and Europe. The nearest modern analogues of this flora are assemblages deposited in small lakes in the high arctic and present day periglacial environments. Based on the diatoms present, the most probable depositional habitat was the margin of a moderately alkaline (pH>7.0) and moderately productive pond which existed under arctic conditions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43068/1/10933_2004_Article_BF00177765.pd

Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

A PRELIMINARY INVESTIGATION OF THE PHYLOGENETIC RELATIONSHIPS AMONG THE FRESHWATER, APICAL PORE FIELD-BEARING CYMBELLOID AND GOMPHONEMOID DIATOMS (BACILLARIOPHYCEAE) 1

Relationships among the apical pore field-bearing diatom genera Brebissonia, Cymbella, Gomphonema, Gomphoneis, Didymosphenia, Gomphocymbella, and Reimeria and their close ally Encyonema were evaluated using cladistics. These biraphid genera are a polythetic group defined by chloroplast number and type, mode of sexual reproduction, valve orientation and presence of apical pore fields. Character states of valve as well as non-siliceous features were described and then polarized using the outgroup method, with the naviculoid genera Anomoeoneis and Placoneis serving as outgroups. The cladistic analysis suggests two groups of terminal taxa, corresponding to to a predominantly cymbelloid lineage and a gomphonemoid lineage. Didymosphenia, previously thought to be closely allied to gomphonemoid diatoms, is shown to be more closely related to Cymbella. Gomphonema appears to be without distinguishing characteristics. Relationships of the other genera are described. The systematic position of small, doubly-punctate Gomphonema species is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65441/1/j.1529-8817.1988.tb04480.x.pd