Growth and photosynthetic down-regulation in Coffea arabica in response to restricted root volume

Coffee (Coffea arabica L.) plants were grown in small (3-L), medium (10-L) and large (24-L) pots for 115 or 165 d after transplanting (DAT), which allowed different degrees of root restriction. Effects of altered source : sink ratio were evaluated in order to explore possible stomatal and non-stomatal mechanisms of photosynthetic down-regulation. Increasing root restriction brought about large and general reductions in plant growth associated with a rising root : shoot ratio. Treatments did not affect leaf water potential or leaf nutrient status, with the exception of N content, which dropped significantly with increasing root restriction even though an adequate N supply was available. Photosynthesis was severely reduced when plants were grown in small pots; this was largely associated with non-stomatal factors, such as decreased Rubisco activity. At 165DAT contents of hexose, sucrose, and amino acids decreased in plants grown in smaller pots, while those of starch and hexose-P increased in plants grown in smaller pots. Photosynthetic rates were negatively correlated with the ratio of hexose to free amino acids, but not with hexose content. Activities of acid invertase, sucrose synthase, sucrose-P synthase, fructose-1,6- bisphosphatase, ADP-glucose pyrophosphorylase, starch phosphorylase, glyceraldehyde-3-P dehydrogenase, PPi : fructose-6-P 1-phosphotransferase and NADP : glyceraldehyde-3-P dehydrogenase all decreased with severe root restriction. Glycerate-3-P : Pi and glucose-6-P : fructose-6-P ratios decreased accordingly. Photosynthetic down-regulation was unlikely to have been associated directly with an end-product limitation, but rather with decreases in Rubisco. Such a down-regulation was largely a result of N deficiency caused by growing coffee plants in small pots.

Field study on nematode resistance in Nelore-breed cattle

The present study evaluated Nelore cattle with different degrees of resistance to natural infections by gastrointestinal nematodes. One hundred weaned male cattle, 11-12 months of age, were kept on the same pasture and evaluated from October 2003 to February 2004. Faecal and blood samples were collected for parasitological, haematological and immunological tests. In February 2004, the 10 most resistant and the 10 most susceptible animals were selected based on individual means of nematode faecal egg counts (FEC). Such animals were slaughtered for worm burden determination and nematode species identification. The repeatability estimates for FEC (+/- S.D.), log-transformed FEC and packed-cell volume (PCV) in all animals were 0.3 (+/- 0.05), 0.26 (+/- 0.04) and 0.42 (+/- 0.05), respectively. The resistant group showed lower FEC and worm burdens than the susceptible group (P < 0.05). There were no significant differences between groups regarding mean body weight, weight gain, PCV and total serum protein values (P > 0.05). The resistant group showed higher total serum IgE levels (P < 0.05) and higher mean eosinophil blood counts. However, the latter was statistically significant only 42 days after the beginning of the study. Nematodes Cooperia punctata and Haemonchus placei were predominant and the correlation between Cooperia and Haemonchus burdens was 0.64 (P < 0.05), which indicated that animals presenting increased numbers of one of those genera probably had increased numbers of the other. The current study provides further evidence of IgE active role in nematode immunity and suggests that total serum IgE level might serve as an additional marker to select Nelore cattle that are responsive to H. placei and C. punctata infections. (C) 2007 Elsevier B.V. All rights reserved.

Efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by Haemonchus and Trichostrongylus species in lambs at pasture

The efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by trichostrongyle nematodes in sheep was assessed throughout 6 months. Twenty Ile de France lambs were divided into two groups (control and treated groups), which were kept in separate pastures. Animals of the treated group were fed with D. flagrans twice a week (Tuesdays and Fridays). Pellets were prepared with the fungus mycelia in liquid culture medium and contained approximately 20% fungus. They were mixed with the animals' diet at a concentration of 1 g pellet per 10 kg live weight. Faecal egg counts (FEC), packed cell volume (PCV), total serum protein and the animals' body weight were determined fortnightly from 7 October 2005 to 24 March 2006. Comparison of such parameters between groups showed no significant differences (P > 0.05), except on 10 February 2006, when the control group presented a higher mean FEC than the treated group (P < 0.05). Feeding sheep with pellets containing D. flagrans had no benefit to the prophylaxis of nematode infections under the experimental conditions used in the present study.

Comparison of the susceptibility of Santa Ines and Ile de France ewes to nematode parasitism around parturition and during lactation

Breeds of sheep with resistance to nematode infection often display a reduced periparturient rise (PPR) in faecal egg counts (FEC) when compared with susceptible sheep. This trial was carried out to compare the resistance of Santa Ines, an indigenous Brazilian breed of sheep, and Ile de France ewes to natural infections by gastrointestinal nematodes, especially in the periparturient period. Twelve Santa lnes and 10 Ile de France ewes were estrus synchronized and then mated (December 2001). Lambing occurred from 30 April to 19 June 2002 and the lambs were weaned at 60 days of age. Faecal egg counts, packed cell volume (PCV), total plasma protein levels and peripheral eosinophils counts were determined from November 2001 to September 2002. To prevent deaths, individual treatment with anthelmintics was provided to ewes with FEC higher than 4000 eggs per gram (EPG) or with PCV lower than 21%. The percentage of Santa Ines ewes treated with anthelmintics was lower than that of Ile de France sheep. Eight of the 10 Ile de France ewes were treated, with one of them requiring four treatments, one requiring three treatments, and two requiring two treatments. The remaining four received a single treatment. In contrast, only 5 of the 12 Santa lnes ewes required treatment and for each this was done only once. The mean values of PCV were in the normal range in the Santa Ines ewes. In contrast, mean PCVs of Ile de France ewes reached a low of 24.5% in the second month after lambing and were significantly lower than Santa Ines 1 month before lambing (P < 0.05) and 2 months after lambing (P < 0.07). The mean plasma protein level was significantly lower in the Ile de France ewes in the second month after lambing (P < 0.01) coinciding with a reduction in PCV. The ewes of both breeds had high mean numbers of eosinophils in blood, which increased even further post-weaning when a marked reduction in FEC occurred. Haemonchus larvae were the most numerous genus in faecal cultures for both breeds followed by Trichostrongylus, Oesophagostomum and Cooperia. A periparturient rise in FEC was observed in both breeds. However, Santa Ines ewes showed a higher capacity to support the infection in an environment contaminated with large number of infective larvae of gastrointestinal nematodes. (C) 2004 Elsevier B.V. All rights reserved.

Nematode burdens and cellular responses in the abomasal mucosa and blood of Florida Native, Rambouillet and crossbreed lambs

This experiment was carried out to compare the worm burden and cellular responses in the abomasal mucosa and blood of Florida Native and Rambouillet lambs and also in animals produced by crosses of these two breeds (generations F1 and F2). Animals were exposed to infection by gastrointestinal nematodes on three different occasions. The first infection was natural, occurring while they were suckling lambs. After weaning, they were kept indoors for 53 days and then were allowed to graze a contaminated pasture for 50 days for a second natural infection. The third infection was an artificial challenge with 6000 Haemonchus contortus infective larvae. The highest mean fecal egg counts (FEC) values were found in Rambouillet lambs followed in decreasing order by F1, F2 and Florida Native lambs. Throughout the trial, most of the high mean packed cell volumes and plasma protein levels were recorded in the F2 lambs; in contrast, most of the low values were found in the Rambouillet lambs. During the natural infection period, the highest percentages of larvae in the fecal cultures of the lambs were Haemonchus. However, high percentages of Trichostrongylus larvae were found particularly in Florida Native lambs. The mean number of blood eosinophils increased after the artificial challenge, reached a peak 21 days after infection and then declined. The highest and lowest blood eosinophil means were recorded in F2 and Florida Native lambs, respectively. The H. contortus burden was significantly higher in Rambouillet and in F1 lambs than in Florida Native and F2 lambs (p < 0.05), while no significant differences were recorded among eosinophil, mast cell and globule leucocyte counts in the abomasal mucosa (p > 0.05). The highest correlation coefficient recorded at the end of this study was between FEC and worm burden (r = 0.7). These two parameters showed a moderate negative correlation with PCV, plasma protein and mast cell counts in the abomasal mucosa. The results obtained in this study indicate that crossbreeding Florida Native and Rambouillet sheep can be a rapid way to combine and improve the characteristics of these two breeds. The parasitological results were promising. however, more studies will be necessary to verify the impact of crossbreeding in other traits. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Resistance of Santa Ines, Suffolk and Ile de France sheep to naturally acquired gastrointestinal nematode infections

A study was conducted to assess the breed resistance against nematode infections in Santa Ines, Ile de France and Suffolk male lambs over a 9-month period in São Paulo state, Brazil. Lambs were born during the winter (year 2000) and were weaned at 2 months of age. The animals were then housed and treated with anthelmintics to eliminate natural infections by gastrointestinal nematodes. In late October 2000, lambs were placed in a paddock, where they stayed until August of the following year. Fecal and blood samples were taken from each animal every 2 weeks. on the same day, a pasture sample was collected to determine the number of infective larvae on the herbage. To prevent deaths, individual treatment with anthelmintics was provided to lambs with fecal egg counts (FEC) higher than 4000 eggs per gram (EPG) or with a packed cell volume (PCV) lower than 21%. In August 2001, all animals were slaughtered and the worms present in samples of the gastrointestinal contents were identified and counted. Most of the Suffolk and Ile de France sheep received three to six anthelmintic treatments over a period of 7 months, while most of the Santa Ines were not treated. Reductions in PCV and plasma protein values associated with high FEC and worm burdens were recorded, particularly, in Suffolk and Ile de France lambs. Haemonchus contortus and Oesophagostomum columbianum burdens and number of nodular lesions caused in the large intestine by O. columbianum larvae were significantly lower in Santa Ines sheep. All three breeds showed similar Trichostrongylus colubriformis worm burdens. The relative resistance of Santa Ines young male sheep was superior to that of Suffolk and Ile de France sheep. (C) 2004 Elsevier B.V. All rights reserved.

Parasitism by Oestrus ovis: Influence of sheep breed and nematode infections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Resistance of Santa Ines and crossbred ewes to naturally acquired gastrointestinal nematode infections

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

First assessment of the endoparasitic nematode fauna of four psammophilous species of Tropiduridae (Squamata: Iguania) endemic to north-eastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nematode infection in the lizard Bogertia lutzae (Loveridge, 1941) from the Atlantic forest in north-eastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NEW HOSTS and DISTRIBUTION RECORDS FOR NEMATODE PARASITES of FRESHWATER FISHES FROM São Paulo STATE, BRAZIL.

A study on the nematode parasites of nine species of freshwater fishes from Peixe River São Paulo, State, Brazil. was conducted. Fish were collected between February 2010 and March 2011 and the following species were found: Procamallanus (Spirocamallanus) inopinatus and Contracaecum sp. (larvae) in Astyanax altiparanae; Contracaecum sp. (larvae), Dioctophyma renale (larvae), Philometroides caudata, P. (Spirocamallanus) inopinatus, P. (Spirocamallanus) neocaballeroi (larvae) and P. (Spirocamallanus) saofranciscensis in Acestrorhynchus lacustris; Contracaecum sp. (larvae), Guyanema sp., Hysterothylacium sp. (larvae) and Icthyouris sp. in Cyphocharax modestus; Contracaecum sp. (larvae), Cosmoxynemoides aguirrei and Pharyngodonidae gen. sp. in C. nagelii; Dioctophyma renale (larvae), Hysterothylacium sp. (larvae) and Rhabdochona sp. in Gymnotus sylvius; Capillariidae gen. sp. in Hoplosternum littorale; Cosmoxynema vianai, Guyanema sp., Ichthyouris sp. and Travnema travnema in Steindachnerina insculpta; Contracaecum sp. (larvae), Procamallanus (Spirocamallanus) rebecae (larvae) in Triportheus angulatus and Rhabdochona acuminata in Triportheus nematurus. This is first study of nematode parasites from the Peixe River, therefore all the species found are new geographical records and 19 are new host records.

Action mechanisms of petroleum hydrocarbons present in waters impacted by an oil spill on the genetic material of Allium cepa root cells

Chromosomal aberration (CA) assays have been widely used, not only to assess the genotoxic effects of chemical agents, but also to evaluate their action mechanisms on the genetic material of exposed organisms. This is of particular interest, since such analyses provide a better knowledge related to the action of these agents on DNA. Among test organisms, Allium cepa is an outstanding species due to its sensitivity and suitable chromosomal features, which are essential for studies on chromosomal damage or disturbances in cell cycle. The goal of the present study was to analyze the action mechanisms of chemical agents present in petroleum polluted waters. Therefore, CA assay was carried out in A. cepa meristematic cells exposed to the Guaeca river waters, located in the city of Sao Sebastiao, SP, Brazil, which had its waters impacted by an oil pipeline leak. Analyses of the aberration types showed clastogenic and aneugenic effects for the roots exposed to the polluted waters from Guaeca river, besides the induction of cell death. Probably all the observed effects were induced by the petroleum hydrocarbons derived from the oil leakage. (C) 2008 Elsevier B.V. All rights reserved.

Aluminum in corn plants: influence on growth and morpho-anatomy of root and leaf

A toxicidade do alumínio (Al) é um dos fatores mais limitantes para a produtividade. Esta pesquisa foi realizada para avaliar a influência do Al, em solução nutritiva, na altura de plantas, no peso da matéria seca e nas alterações morfoanatômicas de raízes e folhas de milho (Zea mays L.). O experimento foi conduzido em casa de vegetação com tratamentos constituídos de cinco doses de Al (0; 25; 75; 150; e 300 µmol L-1) e seis repetições. As soluções foram constantemente aeradas e o pH foi ajustado a 4,3, inicialmente. A matéria seca da parte aérea e das raízes e a altura das plantas diminuíram significativamente com o aumento da concentração de Al. As raízes de plantas de milho cultivadas em soluções com Al tiveram seu crescimento inibido e apresentaram menos raízes laterais e desenvolvimento do sistema radicular inferior, em comparação com as das plantas-controle. As folhas das plantas crescidas em soluções que continham 75 e 300 µmol L-1 de Al não apresentaram muita diferença anatômica em relação às das plantas-controle. A bainha da folha das plantas exposta ao Al apresentou epiderme uniestratificada revestida por uma fina camada de cutícula e as células da epiderme e do córtex foram as que menos se desenvolveram. No feixe vascular, o metaxilema e protoxilema não tinham paredes secundárias, e o diâmetro de ambos foi muito menor quando comparado com os das plantas-controle.

Root, shoot and leaf traits of the congeneric Styrax species may explain their distribution patterns in the cerrado sensu lato areas in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of enzymatic hydrolysis on some physicochemical properties of root and tuber granular starches

A hidrólise enzimática do amido pode fornecer informações importantes sobre sua estrutura granular. Amidos de mandioca, batata-doce, mandioquinha-salsa e batata foram hidrolisados por α-amilase bacteriana a 37 °C durante 48 horas, e algumas propriedades físico-químicas dos resíduos da hidrólise foram determinadas. O amido de mandioca foi o mais suscetível à enzima com 20,9% de hidrólise, enquanto o amido de batata foi o mais resistente com 5,9%. O tamanho médio dos grânulos variou de 10,8 a 23,4 μm para os amidos de mandioquinha-salsa e batata, respectivamente. Amidos de mandioca e batata-doce apresentaram um padrão de difração de raio-X tipo A, enquanto os amidos de mandioquinha-salsa e batata mostraram padrão tipo B. Todos os amidos nativos mostraram superfície granular lisa e, após hidrólise, os amidos de mandioca, batata-doce e mandioquinha-salsa mostraram alguns grânulos bastante degradados, enquanto o amido de batata apresentou sutil sinal de degradação. O teor de amilose dos amidos diminuiu com a hidrólise para os amidos de mandioca, batata-doce e mandioquinha-salsa, permanecendo inalterado para o amido de batata. Como esperado, a viscosidade intrínseca e as propriedades de pasta diminuíram para todos os amidos hidrolisados. Não houve diferença significativa entre as propriedades térmicas dos amidos nativos e hidrolisados. Estes resultados sugeriram que a hidrólise ocorreu nas áreas cristalinas e amorfas dos grânulos. O padrão de difração do tipo B e o grande tamanho dos grânulos do amido de batata podem ter contribuído para a maior resistência deste amido à hidrólise.