Relógio circadiano em eucariotos fotossintetizantes (Archaeplastida) e adaptação ao estresse / Circadian clock in photosynthetic eukaryotes (Archaeplastida) and stress adaptation

Relógios endógenos controlam grande parte de processos biológicos através de osciladores bioquímicos que coordenam a sinalização de pistas ambientais até vias metabólicas, permitindo a percepção do tempo e adaptação a mudanças rítmicas. Comportamentos cíclicos diários foram primordialmente descritos em plantas e, mais recentemente, têm fornecido informações valiosas sobre os ciclos de retroalimentação da transcrição e tradução de genes que controlam estes osciladores. O florescimento é um exemplo bem conhecido da importância da percepção do comprimento do dia através do relógio, processo intimamente regulado por fotorreceptores e pelos genes centrais e periféricos do relógio biológico. Em organismos multicelulares há uma combinação específica de genes mais expressa em cada tecido, podendo ter funções, fases e períodos diferentes, o que aumenta a complexidade desse mecanismo. Devido a isso, tem-se buscado modelos alternativos mais simples dentro dos eucariotos fotossintetizantes relacionados às plantas terrestres. Modelos simplificados facilitam, por exemplo, a avaliação da combinação de fatores que induzem o estresse e como o relógio biológico se altera, permitindo a antecipação de mudanças ambientais e sincronização da fisiologia com o meio ambiente. Neste trabalho, verificou-se como o relógio circadiano se ajusta ao estresse em 3 diferentes modelos: Gracilaria tenuistipitata (Rhodophyta), Ostreococcus tauri (Chlorophyta) e Saccharum sp (Embryophyta). Para isso, estabeleceu-se em G. tenuistipitata métodos para avaliação de crescimento e da fluorescência da clorofila de modo automático, comprovando da existência de ritmos circadianos. Além disso, após padronização de genes de referência para normalização das RT-qPCRs, o gene TRX ficou superexpresso durante a primeira hora após o déficit hídrico. Já em O. tauri, onde os genes centrais do relógio são conhecidos, mudanças na expressão de LOV-HK e TOC1 estão relacionadas com maior crescimento em baixa e alta temperatura, respectivamente. Uma combinação específica de luz, temperatura e salinidade pode ser um importante indutor de eflorescências que reflete mudanças transcricionais no oscilador central, o que pode ser comparado às florescências de plantas terrestres. Já em Saccharum sp tolerante à seca, ritmos de fotossíntese e de expressão de CCA1 sofrem mudanças de fase em suas oscilações e transcritos de HVA-22 e DRP são significativamente mais expressos sob dessecação. Em suma, o estresse em Saccharum sp reseta o relógio, aumentando o período de oscilação da fotossíntese. Em O. tauri induz maior crescimento, mantendo as características do relógio. Não foi possível avaliar o efeito do estresse no relógio de G. tenuistipitata, mas ferramentas foram desenvolvidas visando este objetivo. Estudos de respostas do relógio podem fornecer informações valiosas para o entendimento da reprodução e crescimento de organismos com elevado potencial de aplicações biotecnológicas

Endogenous clocks control a large range of biological processes through biochemical oscillators that coordinate the signaling of environmental cues to metabolic pathways, allowing the perception of time and adjust to rhythmic changes. Cyclical daily behaviors were first noticed in plants and, more recently, revealed information about the transcriptional-translational feedback loops of genes that control these oscillators. Flowering is a well-known process where the perception of day length by the clock is intimately regulated by photoreceptors and by the central and peripheric genes of the biological clock. Multicellular organisms have a tissue-specific combination of expressed clock genes that may have different phase and period, increasing the complexity of this mechanism. Due to this reason, alternative models have been proposed for land plants-related photosynthetic eukaryotes. New models can simplify, for example, which combination of factors induce stress and how the biological clock is altered, allowing the anticipation of environmental changes and synchronization of physiology and environmental factors. This work aimed to verify how the biological clock adjusts to different kinds of stresses in 3 species: Gracilaria tenuistipitata (Rhodophyta), Ostreococcus tauri (Chlorophyta) and Saccharum sp (Embryophyta). Automated measurement techniques for growth rate and photosynthesis were stablished for the red alga. This alga also showed, after establishment of reference genes for RT-qPCRs normalization, an overexpression of TRX during the first hour under water deficit. In O. tauri, where the central clock genes are known, changes in LOV-HK and TOC1 gene expression are related to a higher growth rate under low and high temperatures, respectively. Besides, a specific combination of light, temperature and salinity can be an important trigger of seasonal blooms that causes important transcriptional changes at the central oscillator, what is similar to land plants. In Saccharum sp tolerant to drought, photosynthesis rhythms and CCA1 expression change their phase under simulated water deficit and drought responsive transcripts like HVA-22 and DRP are significantly up-regulated. In short, stress resets the clock in Saccharum sp, increasing the period of photosynthesis oscillation. In O.tauri, it induces a higher growth, keeping clock features. It was not possible to verify clock responses to stress in G.tenuistipitata, but methods to do so were stablished. The biological clock responses to stress can provide invaluable information for the better understanding about the growth and reproduction of organisms with a high biotechnological potential

Distribution of periphytic algae in wetlands (Palm swamps, Cerrado), Brazil / Distribuicao de algas perifiticas em areas umidas (Veredas, Cerrado), Brasil

The distribution of periphytic algae communities depends on various factors such as type of substrate, level of disturbance, nutrient availability and light. According to the prediction that impacts of anthropogenic activity provide changes in environmental characteristics, making impacted Palm swamps related to environmental changes such as deforestation and higher loads of nutrients via allochthonous, the hypothesis tested was: impacted Palm swamps have higher richness, density, biomass and biovolume of epiphytic algae. We evaluated the distribution and structure of epiphytic algae communities in 23 Palm swamps of Goiás State under different environmental impacts. The community structure attributes here analyzed were composition, richness, density, biomass and biovolume. This study revealed the importance of the environment on the distribution and structuration of algal communities, relating the higher values of richness, biomass and biovolume with impacted environments. Acidic waters and high concentration of silica were important factors in this study. Altogether 200 taxa were identified, and the zygnemaphycea was the group most representative in richness and biovolume, whereas the diatoms, in density of studied epiphyton. Impacted Palm swamps in agricultural area presented two indicator species, Gomphonema lagenula Kützing and Oedogonium sp, both related to mesotrophic to eutrophic conditions for total nitrogen concentrations of these environments.

A distribuição de comunidades de algas perifíticas depende de vários fatores, como tipo de substrato, nível de distúrbio, disponibilidade de nutrientes e luz. De acordo com a predição de que impactos de ação antrópica proporcionam alterações nas características ambientais – tornando Veredas impactadas relacionadas a alterações ambientais, como desmatamentos e maiores cargas de nutrientes via alóctone –, a hipótese testada foi: Veredas impactadas apresentam maiores riqueza, densidade, biomassa e biovolume de algas epifíticas. Avaliaram-se a distribuição e a estruturação de comunidades de algas epifíticas em 23 Veredas do Estado de Goiás sob diferentes impactos ambientais. Os atributos da estrutura de comunidade avaliados foram composição, riqueza, densidade, biomassa e biovolume. Este estudo revelou a importância das características ambientais na distribuição e na estruturação das comunidades de algas, relacionando os maiores valores de riqueza, biomassa e biovolume dos organismos aos ambientes impactados. Águas ácidas e altas concentrações de sílica foram fatores importantes no estudo. Ao todo, foram identificados 200 táxons, sendo as zignemafíceas o grupo mais representativo em riqueza e biovolume, enquanto as diatomáceas, as mais representativas em densidade do epifíton estudado. Veredas impactadas em área de agropecuária apresentaram duas espécies indicadoras, Gomphonema lagenula e Oedogonium sp., ambas relacionadas com condições mesotróficas a eutróficas, para concentrações de nitrogênio total desses ambientes.

Recent dynamics and condition of coral reefs in the Colombian Caribbean

Long-term monitoring data provide a basis to recognize changes in coral reef communities and to implement appropriate management strategies. Unfortunately, coral reef dynamics have been poorly documented at any temporal scale in the Southern Caribbean. Through the "National Monitoring System of Coral Reefs in Colombia" (Spanish acronym: SIMAC), we assessed 32 permanent plots at different depth levels in six reefs areas of the Colombian Caribbean from 1998 to 2004. Temporal trends in coral and algal cover were evaluated by repeated measures ANOVA. The model included the effect of depth levels (a fixed effect), monitoring plots (a random effect) as a nested factor within depths, and time (repeated factor). We found high spatial variability in major benthic components. Overall means indicated that algae were the most abundant biotic component in nearly all areas, ranging from 30.3% at Rosario to 53.3% at San Andrés. Live coral cover varied considerably from 10.1% at Santa Marta up to 43.5% at Urabá. Coral and algae cover per se are not always accurate reef indicators and therefore they need supplementary information. Temporal analyses suggested relative stability of coral and algal cover along the study but the causes for the observed trends were rarely identified. A significant decrease (p=0.042) in coral cover was only identified for some monitoring plots in Tayrona-time x plot (depth level) interaction, and importantly, few coral species explained this trend. Significant increase (p=0.005) in algal cover was observed over time for most plots in Rosario. Temporal trajectories in algal cover were influenced by depth-significant time x depth interaction-in San Andrés (increase, p=0.004) and Urabá (decrease, p=0.027). Algae trends were mainly explained by changes in algal turfs. Monitoring programs must focus on the mechanisms mediating the changes, in particular those concerning coral recovery and reef resilience in the current context of climate change. Rev. Biol. Trop. 58 (Suppl. 1): 107-131. Epub 2010 May 01.

Este trabajo contiene el primer análisis temporal de la información obtenida por el Sistema Nacional de Monitoreo de Arrecifes Coralinos en Colombia (SIMAC). Entre 1998 y el 2004 se monitorearon un total de 32 parcelas permanentes ubicadas a diferentes niveles de profundidad en seis áreas arrecifales del Caribe colombiano. Los patrones temporales de algas y corales fueron evaluados mediante análisis de varianza de medidas repetidas. Los promedios generales indicaron que las algas dominaron en la mayoría de las áreas evaluadas, variando de 30.3% (Rosario) hasta 53.3% (San Andrés). La cobertura coralina fluctuó considerablemente entre 10.1% (Santa Marta) y 43.5% (Urabá). Los arrecifes estudiados han permanecido relativamente estables durante el periodo evaluado en términos de algas y corales. El único cambio significativo en la cobertura se detectó en algunas parcelas de monitoreo del Tayrona, y pocas especies coralinas explicaron la tendencia de disminución. En Rosario se detectó una tendencia significativa de incremento para las algas en la mayoría de las parcelas. En San Andrés y Urabá las tendencias temporales (aumento y disminución respectivamente) se presentaron en ciertos niveles de profundidad. En estas dos áreas las tendencias en la cobertura de las algas fueron explicadas principalmente por cambios en los tapetes algales. En general las causas de los patrones observados no pudieron identificarse. Los programas de monitoreo deben evaluar no solo las tendencias generales de algas y corales sino también las de sus componentes (especies de coral y grupos funcionales de algas). Así mismo, deben enfocarse en evaluar los mecanismos involucrados en los cambios, en especial aquellos relacionados con la recuperación coralina y la resiliencia arrecifal, de manera que se pueda enfrentar el deterioro arrecifal en el actual contexto de cambio climático.

Macroalgas de ambientes lóticos da região centro-oeste do Paraná, região sul do Brasil / Stream macroalgae from the mid-western region of Paraná State, southern Brazil

Estudos taxonômicos enfocando o inventário de macroalgas de ambientes lóticos em diferentes regiões são considerados importantes contribuições para o conhecimento básico destas comunidades algais. Neste contexto, o principal objetivo desta investigação foi realizar um levantamento florístico das comunidades de macroalgas da região centro-oeste do estado do Paraná, região Sul do Brasil, uma área de clima subtropical pouco investigada. Vinte e dois segmentos de rios/riachos foram amostrados através da técnica da transeção. Vinte e quatro táxons de macroalgas foram encontrados, incluindo 18 táxons subgenéricos e 6 grupos vegetativos. Chlorophyta foi a divisão com maior número de espécies (13 táxons = 54 por cento), seguida por Cyanophyta (cinco táxons = 21 por cento) e Rhodophyta e Heterokontophyta (3 táxons = 12,5 por cento cada uma). Phormidium retzii (C. Agardh) Gomont (Cyanophyta) foi a espécie melhor distribuída, e emaranhados de filamentos o tipo morfológico predominante. Apesar de todos os táxons já tenham sido previamente descritos para ambientes lóticos brasileiros, 5 espécies são novos registros para o estado do Paraná. Embora sem nenhuma espécie nova registrada, o levantamento taxonômico da região centro-oeste do estado do Paraná é extremamente relevante, uma vez que ele amplia as distribuições geográfica e ambiental das comunidades de macroalgas no Brasil.

Taxonomic studies focusing on the inventory of lotic macroalgae in different regions are important contributions to the basic knowledge for these algal communities. In this context, the main objective of this investigation was to accomplish a floristic survey of the stream macroalgal communities in the mid-west region of Paraná State, Southern Brazil, a poorly investigated subtropical area. Twenty-two stream segments were sampled by means of cross-transect technique. Twenty-four macroalgal taxa were found, including 18 subgeneric taxa and 6 vegetative groups. Chlorophyta was the most species rich division (13 taxa = 54 percent of the total), followed by Cyanophyta (five taxa = 21 percent) and Rhodophyta and Heterokontophyta (3 taxa = 12.5 percent). Phormidium retzii (C. Agardh) Gomont (Cyanophyta) was the most widespread species, and mats the predominant morphological type. Although all the macroalgal taxa had been previously described from Brazilian streams, 5 species are new records from Paraná State. Even with no additional species reported, the survey in the mid-west region of Paraná State are relevant, since it expanded the geographical and environmental distribution of the stream macroalgal communities in Brazil.

Discrepancy variation of dinucleotide microsatellite repeats in eukaryotic genomes

To address whether there are differences of variation among repeat motif types and among taxonomic groups, we present here an analysis of variation and correlation of dinucleotide microsatellite repeats in eukaryotic genomes. Ten taxonomic groups were compared, those being primates, mammalia (excluding primates and rodentia), rodentia, birds, fish, amphibians and reptiles, insects, molluscs, plants and fungi, respectively. The data used in the analysis is from the literature published in the Journal of Molecular Ecology Notes. Analysis of variation reveals that there are no significant differences between AC and AG repeat motif types. Moreover, the number of alleles correlates positively with the copy number in both AG and AC repeats. Similar conclusions can be obtained from each taxonomic group. These results strongly suggest that the increase of SSR variation is almost linear with the increase of the copy number of each repeat motif. As well, the results suggest that the variability of SSR in the genomes of low-ranking species seem to be more than that of high-ranking species, excluding primates and fungi.

Notes on freshwater and terrestrial algae from Ny-Alesund, Svalbard (high Arctic sea area).

Field survey of algae and cyanobacteria from terrestrial and freshwater habitats in the vicinity of arctic Ny-Alesund, Svalbard (790N) (high Arctic sea area) was performed in June 2006. Species diversity and abundance were evaluated by using epifluorescence microscopy and culturing methods. In total, 29 taxa in 25 genera were identified, of which Leptolyngbya spp., Trichormus sp. and Chlamydomonas nivalis were abundantly present in almost every sample. In several locations, blooms were formed by species C. nivalis, Scotiellopsis sp., Klebsormidium flaccidum, Zygnema sp., Meridion circulare, Tabellaria fenestrata and Fragilaria sp. Eleven new species from this locality are described.

Morphology and ecology of the planktonic diatom Palmerina hardmaniana (Greville) Hasle in southern Brazil / Morfologia e ecologia de diatomácea planctônica Palmerina hardmaniana (Greville) Hasle no Sul do Brasil

The diatom Palmerina hardmaniana (Greville) Hasle presents a wide geographical distribution in neritic tropical and subtropical regions. In the present work we analyzed plankton samples collected monthly between 1995 and 2007 at the surf zone of Cassino Beach, RS (32º 12' S and 52º 10' W), and in winter 2005 and summer 2007 at the continental shelf and slope in southern Brazil, Santa Marta Grande Cape, SC and Albardão-Chuí, RS regions (28º 23'-33º 07' S and 48º 41'-52º 26' W). We present the detailed morphological description of P. hardmaniana, and the first study including electron scanning microscope observations for material from the southwestern Atlantic Ocean. The morphometric data confirm the identity of the species in all its ultra-structural details. Palmerina hardmaniana was only observed in summer-autumn months with low cell density (< 500 cells.L-1) at both Cassino Beach surf zone and coastal shelf stations. The warm water temperature (18-29 ºC) indicates the most probable origin of its inoculum are tropical/subtropical regions. Salinities of 23-36 and the relatively high silicate content indicate the importance of the terrestrial discharge during occasions when P. hardmaniana was observed, probably with influence on the nutrient availability. We emphasize that the species was not cited previously for Argentinean and Uruguayan waters and suggest that the southern Brazilian region is close to the southern geographical distribution limit of Palmerina hardmaniana in the southwestern Atlantic Ocean.

A diatomácea Palmerina hardmaniana (Greville) Hasle apresenta ampla distribuição geográfica em águas neríticas tropicais e subtropicais. No presente trabalho foram analisadas amostras de plâncton, coletadas mensalmente entre 1995 e 2007 na zona de rebentação da Praia do Cassino, RS (32º 12' S e 52º 10' W), e no inverno de 2005 e verão de 2007 na plataforma continental e talude do sul do Brasil, na região de Cabo de Santa Marta Grande, SC e Albardão-Chuí, RS (28º 23'-33º 07' S e 48º 41'-52º 26' W). Apresentamos a descrição detalhada de P. hardmaniana, como primeiro estudo com observações de microscopia eletrônica de varredura para material coletado em águas do Oceano Atlântico Sul Ocidental. Os dados morfológicos analisados confirmam a identificação da espécie em todos os seus detalhes estruturais. Palmerina hardmaniana somente foi observada nos meses de verão/outono, em baixa densidade (< 500 células.L-1) na zona de arrebentação da Praia do Cassino bem como em estações costeiras da plataforma continental. A temperatura quente da água (18-29 ºC), indica as águas tropicais/subtropicais como possível origem do inóculo de P. hardmaniana no verão-outono. A salinidade entre 23 e 36 e o teor relativamente alto de sílica também indicam a importância da descarga terrestre nas ocasiões de presença de P. hardmaniana, exercendo importante papel no suprimento de nutrientes. Salienta-se que a espécie não é citada em águas argentinas e uruguaias e assim, sugerimos que o extremo sul do Brasil representa aproximadamente o limite sul da distribuição geográfica de Palmerina hardmaniana no Oceano Atlântico Sul Ocidental.

Variación estructural de la comunidad perifítica colonizadora de sustratos artificiales en la zona de ritral del río Medellín, Colombia

Variation in the structure of the periphytic community that colonizes artificial substrata in the Medellín river (Colombia). Weekly samples were taken from microscope glass slides attached to acrylic substrata were placed at subsuperficial level in two sampling stations in the higher section of the Medellín river, Colombia, from January through March 1998. Diversity and evenness varied with time (Friedman p<0.05). There were spatial differences in biomass, productivity, diversity and evenness (Friedman p<0.05). Total biomass and productivity increased with the time of colonization at station 1. Station 2, with four times more water flow, had lower diversity and mean evenness values. During the colonization process the were 76 species (22 families). The Chrysophyta, mainly diatoms, were the most abundant (56 % of the total), followed by Clorophyta (29 %), Cyanophyta (11 %) and Cryptophyta (4 %). Rev. Biol. Trop. 55 (2): 585-593. Epub 2007 June, 29.

Se colocaron muestreadores de material acrílico con portaobjetos a nivel subsuperficial en dos estaciones de recolección en la parte alta del río Medellín. De enero a marzo de 1998 se tomaron muestras semanales y se encontraron diferencias temporales significativas en la diversidad y en la equidad (Friedman p<0.05). A nivel espacial hubo diferencias en la biomasa, la productividad, la diversidad y la equidad (Friedman p<0.05)). La biomasa total y la productividad aumentaron con el tiempo de colonización en la estación 1. La estación 2, que tiene un caudal cuatro veces mayor, tuvo menor diversidad y equidad media. Durante el proceso de colonización se encontraron 76 especies pertenecientes a 22 familias, siendo la división de las crisofitas, principalmente diatomeas, la más abundante (56 % del total), seguida por clorofíceas (29 %), cianofíceas (11 %) y criptofíceas (l 4 %).

An ecologic and taxonomic study on phytoplankton of a shallow lake, Turkey.

The middle Black sea region has quite large wetlands, including lakes, rivers, ponds, marshs and large reservoirs. Lake Cernek is one of the most valuable wetlands in Kizilirmak Delta. The lake and its environment have a high biodiversity due to species richness and natural habitats. Therefore, it has been recognized as a Ramsar site. The phytoplankton of lake Cemek consisted of 104 taxa belonging to Cyanobacteria, Bacillariophyta, Chlorophyta, Cryptophyta, Dinophyta, Euglenophyta and Xanthophyta divisions. Chlorophyta (46%) and Bacillariophyta (23%) members were dominant species. These were followed by Cyanobacteria (16%) and Euglenophyta (11%) members. Chlorella, Monoraphidium, Oocystis, Pediastrum and Scenedesmus from Chlorophyceae and also Anabaena, Chroococcus and Microcystis species from Cyanophyceae sometimes made water blooms. Blue green algae constituted algal communities in the surface of the lake in summer months. Algal community and its important species were grouped in terms of bray curtis similarity index, by taking into consideration the phytoplankton dynamics and months.

An assessment of plankton population of Cauvery river with reference to pollution.

Studies on plankton of river Cauvery water, Mettur, Salem District, Tamil Nadu was made to assess the pollution of water from January 2003 to December 2003. The qualitative and quantitative evaluation of the variation in river water showed high quantity of phytoplankton and zooplankton population throughout the study period and rotifers formed dominated group over other groups of organisms. The present study revealed that the water of river Cauvery is highly polluted by direct contamination of sewage and other industrial effluents.

Carboidratos dissolvidos do reservatório de Barra Bonita (Estado de São Paulo, Brasil) e sua relação com as algas fitoplanctônicas abundantes / Dissolved carbohydrates from Barra Bonita Reservoir (São Paulo State, Brazil) and its relationships with phytoplanktonic abundant algae

O estudo dos carboidratos dissolvidos e sua relação com as algas abundantes no reservatório de Barra Bonita, foi realizado em coletas mensais (junho de 2002 a janeiro de 2004), em seis profundidades na coluna d'água, cujos valores variaram dependendo da estação do ano e do nível do reservatório, num ponto fixo, localizado 3 km a montante da barragem. Aproximadamente 90 por cento dos carboidratos dissolvidos neste reservatório foram constituídos por carboidratos poliméricos hidrolisáveis (polissacarídeos ou oligossacarídeos). A análise de variância detectou variabilidade entre as concentrações dos carboidratos dissolvidos apenas em escala temporal (p < 0,05), sendo que no eixo vertical, as concentrações destes açúcares apresentaram-se homogêneas (p > 0,05). A composição monossacarídica dos açúcares encontrados no reservatório foi galactose, ramnose, glicose e fucose. Na maioria dos meses amostrados, as concentrações de carboidratos dissolvidos, a maioria deles poliméricos, ocorreram concomitantemente ao registro de florescimentos das espécies abundantes, principalmente cianofíceas, que provavelmente foram as principais fontes de polissacarídeos extracelulares para o sistema.

Dissolved carbohydrates and abundant algae of Barra Bonita Reservoir were studied monthly from June 2002 to January 2004 in six depths whose values vary depending on the seasons and the water level at a sampling site located 3 km upstream the Reservoir dam. Nearly 90 percent of the dissolved carbohydrates were constituted of polymeric hydrolysable carbohydrates (polysaccharides or oligosaccharides). Analysis of variance detected variability among concentrations of dissolved carbohydrates only in temporal scale (p < 0.05), whereas in vertical axis the concentrations of these sugars were uniform (p > 0.05). The monosaccharide composition of the sugars found in the reservoir was galactose, rhamnose, glucose e fucose. During the sampling period, higher concentrations of dissolved carbohydrates, mostly polymeric, occurred together with large phytoplanktonic blooms, predominantly cyanobacteria, which probably were the main source of extracellular polysaccharides in the system.

Trichrome staining for detection of intestinal protozoa a better screening method.

Intestinal protozoal infections are common in our country because of poor hygiene and tropical conditions. The efficacy of trichrome staining to screen stool smear was compared with commonly used methods i.e. concentrated iodine mount and direct wet mount to test its better effectiveness. All Stool samples were first examined by routine methods i.e. direct wet mount and iodine staining. A portion of stool sample was also inoculated in vial containing polyvinyl alcohol (PVA) fixative. From PVA preserved samples, slides were prepared and stained by modified wheately's trichrome method. The results of both methods were compared and relative accuracy was calculated. 1054 stool specimens were examined and 259 parasites detected, of which 20.7% were protozoa and 3.7% helminthde. Trichrome staining detected 19.1% protozoa while routine methods detected 12.9% protozoa. For identification of protozoa, accuracy was 91.8% in favor trichrome staining and 61.8% by wet mount and iodine staining. Trichrome stained smear alone can be used as screening method in those geographic areas where protozoa infections are common.

Seasonal phytoplanktonic diversity of Kitham lake, Agra.

Two years (Jan. 2000 - Dec. 2001) data on the seasonal studies of phytoplanktonic diversity of Kitham lake (Sur Sarovar) Agra revealed the presence of 73 algal species. A limited number of these were recorded throughout the year, while others were distributed in different seasons mainly in winter and summer seasons. During winters, Chlorophyceae was the most dominant group followed by Bacillariophyceae. On the other hand, Cyanophyceae and Euglenophyceae were the most dominant during summers. Certain species e.g. Pandorina morum, Pediastrum tetras, Gonium sp., Chlorella vulgaris, Scendesmus quadricauda, Oedogonium cardiocum, Synedra ulna, Oscillatoria agardhii and Euglena gracillis were recorded throughout the year. Chlorella, Stigeoclonium, Pandorina, Micratinium, Oscillatoria, Anacystis, Nitzschia and Cymbella were found to be good indicators of water pollution.

Limnological studies of Papnash pond, Bidar (Karnataka).

The Papnash pond is an oldest pond of Bidar, Kamataka state. It is situated at 77 degrees-32 longitude and 17 degrees-55 latitude, located 551 m above mean sea level. It has been used daily for bathing and washing of clothes by large number of pilgrims. The samples were collected fortnightly during October 1999 to September 2000 to analyze physico-chemical and biological status of water, such as temperature, pH, total alkalinity, total hardness, dissolved oxygen, free carbon dioxide, chloride, organic matter, nitrite, phosphate, sulphate and algal flora. Variations in physico-chemical parameters were noted. The results also revealed that the pond water was hard, alkaline and polluted. Totally 39 species of algae were reported from the four classes.

First report of the genus Retortamonas (Sarcomastigophora: Retortamonadidae) in birds

In studies carried out on the parasites infecting ostriches (Struthio camelus) in Spain, trophozoites of Retortamonas sp. have been found in the intestinal contents of 28 out of 146 slaughtered ostriches. The species infecting ostriches could not be determined from the morphological data available. However, these findings are important as they constitute the first report of the genus Retortamonas in birds

Hydrobiological study of Dahikhuta reservoir.

Physico-chemical parameters and the algae of Dahikhuta reservoir, near Malegaon, Dist. Nasik (Maharashtra) have been investigated during July to December 1998. The results have revealed that reservoir water is classified as oligotrophic on the basis of water quality criteria. This paper also reports algal diversity. Total 19 algal taxa are reported from three classes.

Parasitos de los animales domésticos en Chile / Parasites of domestic animals in Chile

An up-to-date list of the parasites that have been identified in horses, cattle, sheep, goats, llamas, alpacas, pigs, dogs, cats, rabbits, chickens and pigeons in Chile, according to the studies performed at the University of Chile and other universities and institutes

Protozoos emergentes. Comparación de tres métodos de identificación / Emergent protozoos. Comparison between three identification methods

Se realizó un estudio comparativo-prospectivo en 541 muestras de heces blanda, muy blandas y líquidas, de niños de un año a 14 años de edad. Se procesaron tres técnicas coproparasitoscópicas (CPS): CPS directo, CPS de concentración por flotación Ferreira y tinción de Kinyoun, para la identificación de Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli y Blastocystis hominis. Los cuatro protozoarios patógenos emergentes fueron identificados en 158 muestras de heces (29.2 por ciento). Dentro de los positivos el 25.9 por ciento correspondió a C. parvum, 11.4 por ciento a C. cayetanensis, 62.0 por ciento a B. hominis y sólo un caso de I. belli. La sensibilidad de la tinción de Kinyoun para C. parbun y C. cayetanensis fue de 100 por ciento y la especificidad de 98.8 por ciento, comparada con CPS Ferreira (p<0.05). La sensibilidad del CPS Ferreira en B. hominis fue 100.0 por ciento y la especificidad de 84.9 por ciento comprada con el CPS directo (p<0.05). Se sugiere que a todas las muestras de heces alteradas en su consistencia se les realice la búsqueda intencionada de estos cuatro patógenos emergentes, mediante CPS convencionales y la tinción de Kinyoun