How does water and salt stress affect the germination and initial growth of Brazilian soya bean cultivars?

The effects of water and salt stress on rate of germination and seedling growth were investigated under laboratory conditions in 46 soya bean genotypes from Central-West region of Brazil to verify how these stresses may limit crop establishment during the initial growth stage and also to identify the most tolerant genotypes to drought and salinity. Mild water and salt stresses were imposed by seed exposure to –0.20 MPa iso-osmotic solutions with polyethylene glycol—PEG 6000 (119.57 g/L) or NaCl (2.357 g/L) for 12 days at 25°C. The germination percentage, seedling length and seedling dry matter were measured, and then, salt or drought tolerance indexes were calculated. The “NS 5909 RG,” “NS 7000 IPRO,” “NS 7338IPRO,” “FPS Solimões RR,” “NS 5151 IPRO,” “SYN 13610 IPRO,” “LG 60177 IPRO,” “NS 6909 IPRO” and “BMX Desafio RR” were identified as the most drought-tolerant genotypes, whereas under salinity conditions, the genotypes “5D 615 RR,” “BMX Desafio RR,” “5D 6215 IPRO” and “BMX Ponta IPRO” were identified as tolerant. The “BMX Desafio RR” is the genotype most adapted to both stress conditions and, therefore, should be used under conditions of water shortage and excess salt in the soil at sowing time.     

A monoclonal antibody against a canine CD45 homologue: analysis of tissue distribution, biochemical properties and in vitro immunological activity

This report describes the characterisation of a monoclonal antibody (mAb), AB6, which recognises specifically a cluster of canine leukocyte surface molecules. The immunogen used for obtaining the AB6 mAb was a lysate of canine peripheral blood mononuclear cells (PBMC). This novel mAb belongs to the IgG2a isotype, and reacted in Western blot with four different canine leukocyte glycoproteins with apparent molecular weights of 180, 190, 205 and 220 kDa. The AB6 mAb recognised the majority of canine peripheral blood leukocytes as determined by flow cytometry (97%). It also exhibited a broad reactivity pattern against lymphoid and myeloid cells, inhibited the proliferation of mitogen-stimulated canine PBMC and did not recognise human PBMC and murine splenocytes. The biochemical properties, cell and tissue specificity, and in vitro biological activity of the AB6 mAb indicate that it recognises a canine CD45 homologue. The mAb could become a valuable diagnostic and research tool for the evaluation of immune functions in dogs.     

Effects of Broomrape Parasitism on Sunflower Plants: Growth,Development, and Mineral Nutrition

Sunflower broomrape (Orobanche cumana Wallr.) is a parasitic plant that infects sunflower (Helianthus annuus L.) plants. In this work, sunflower plants were grown under greenhouse conditions in pots with the substrate infested or non-infested with broomrape seeds. At different numbers of days after sowing, plant height, internode lengths, number of leaves, head diameter, mineral composition of leaves, and potassium (K) concentration in stem were measured. The negative effects of broomrape parasitism were assessed from 57 d after sowing, when broomrape started to emerge. Parasitized plants exhibited lower shoot dry weight, height, and head diameter than control plants. The reduction in internode lengths was associated with a decrease in the gradient of K concentration from basal to apical stem. The mineral composition of leaves was also affected in parasitized plants. The concentrations of calcium (Ca), magnesium (Mg), manganese (Mn), and zinc (Zn) in leaves of parasitized plants were lower than those of the control plants, while there were few differences for K, phosphorus (P), iron (Fe), and copper (Cu). The effects of parasitism are discussed in relation to their competition for resources and to perturbations of the host physiology such as hormonal and water balance.     

Antibacterial and antioxidant activities of essential oils isolated from Thymbra capitata L. (Cav.) andOriganum vulgare L

Antilisterial activities of Thymbra capitata and Origanum vulgare essential oils were tested against 41 strains of Listeria monocytogenes. The oil of T. capitata was mainly constituted by one component, carvacrol (79%), whereas for O. vulgare three components constituted 70% of the oil, namely, thymol (33%), gamma-terpinene (26%), and p-cymene (11%). T. capitata essential oil had a significantly higher antilisterial activity in comparison to O. vulgare oil and chloramphenicol. No significant differences in L. monocytogenes susceptibilities to the essential oils tested were registered. The minimum inhibitory concentration values of T. capitata essential oil and of carvacrol were quite similar, ranging between 0.05 and 0.2 microL/mL. Antioxidant activity was also tested, the essential oil of T. capitata showing significantly higher antioxidant activity than that of O. vulgare. Use of T. capitata and O. vulgare essential oils can constitute a powerful tool in the control of L. monocytogenes in food and other industries.     

Recent research in Roumania on blackleg and bacterial soft rot of potato

Summary Potato blackleg has been known in Roumania for more than 35 years, but has become increasingly serious in recent times. The disease is mainly restricted to the central and northern regions, which have a rainy climate with moderate temperatures. In areas where the climate is warm and dry, the disease appears only sporadically, and even then, its development is slow. The principal means of transmission of the disease from one year to another is by infected tubers, the causal organ does not persist long in unsterile soil. Potato blackleg and soft rot in Roumania is produced not only byE. atroseptica, for an important part in the disease complex especially in storage is played by the bacteriaE. carotovora andE. aroideae. E. atroseptica, owing to its special preference for the stems of the plants, is considered as the principal pathogenic agent, while the other two organisms occur more frequently in the tubers. It is considered that the divergent characteristics of the organisms justify keeping them as two or even three separate species and not as variants of a single species.

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Zusammenfassung In den Jahren 1961 bis 1963 wurden am Biologischen Institut Traian Savulescu in Bukarest, Rum?nien, Untersuchungen durchgeführt über die Verbreitung der Schwarzbeinigkeit bei Kartoffeln im Zusammenhang mit den klimatischen Verh?ltnissen in Rum?nien, mit den Bedingungen, unter welchen die Infektion und die übertragung der Krankheit stattfindet, mit der Etiologie der Krankheit in Rum?nien und mit gewissen charakteristischen Eigenschaften der Krankheitserreger. Kartoffel-Schwarzbeinigkeit ist in Rum?nien schon seit mehr als 35 Jahren bekannt, aber in letzter Zeit hat sie ernstere Formen angenommen. Die Infektion im Feld schwankt von 1–15% und nimmt w?hrend der Lagerung zu. Die Krankheit beschr?nkt sich haupts?chlich auf die zentralen und n?rdlichen Regionen des Landes, wo ein regnerisches Klima mit m?ssigen Temperaturen vorherrscht. Im Süden, wo Frühling und Sommer in der Regel heiss und trocken sind, scheint sie eigentlich nicht vorzukommen, selbst nicht in Feldern, die mit Knollen aus befallenen Gebieten bepflanzt sind. Es ist festgestellt worden, dass die übertragung dieser Krankheit von einem Jahr auf das andere haupts?chlich durch befallene Knollen geschieht. Der Boden bildet nur in dem Mass eine Infektionsquelle, als er nicht verfaulte Reste von kranken Pflanzen enth?lt. Es wurde dargelegt, dass die Bakterien in nicht sterilem Boden ihre überlebensf?higkeit rasch verlieren (Tabelle 1). Was die Etiologie der Schwarzbeinigkeit betrifft, wurde herausgefunden, dass nebenErwinia atroseptica—in Rum?nien bis jetzt als die einzige Ursache dieser Krankheit angenommen — auchE. carotovora undE. aroideae, speziell w?hrend der Lagerung, eine wichtige Rolle im Krankheitskomplex spielen. Unsere Beobachtungen und Untersuchungen haben ergeben, dassE. atroseptica der Hauptkrankheitserreger im Feld ist, der besonders die Stengel bef?llt. Die beiden andern Bakterien kommen ebenfalls vor, doch werden sie gew?hnlich auf den Knollen am Lager gefunden, wo sie — unter günstigen Bedingungen — einen viel h?ufigeren Befall erzeugen k?nnen alsE. atroseptica. Es wurde festgestellt, dass sowohl Eigenschaften, wie der Grad der Pathogenit?t an Stengeln und Knollen, Reaktionen auf Zuckern und besonders das Verhalten auf Maltose und auf durchtr?nktes Korn-Pepton-Glukose-Agar-Medium, das Wachstum bei hohen Temperaturen (Tabelle 2) und serologische Reaktionen (Tabelle 3) wie auch toxische und immunologische Wirkungen auf Tiere bei der Unterscheidung der drei Bakterien von Nutzen sind. Es wird darauf hingewiesen, dass die hier berichteten Ergebnisse die Ansicht jener Forscher best?rken und rechtfertigen, die glauben, dass die drei Bakterien als verschiedene Arten betrachtet werden sollten.

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Résumé A l'Institut de Biologie Traian Savulescu à Bucarest. Roumanie, les recherches suivantes ont été effectuées durant la période 1961–1963; l'apparition de la maladie de la jambe noire en relation avec les conditions climatiques en Roumanie, les conditions sous lesquelles ont lieu l'infection et la transmission de la maladie, l'étiologie de la maladie en Roumanie et certains caractères des pathogènes. La jambe noire de la Pomme de terre est connue en Roumanie depuis plus de 35 ans mais est devenue progressivement grave dans les derniers temps. L'infection dans les champs varie de 1 à 15% et augmente pendant la conservation. La maladie est essentiellement limitée aux régions du centre et du nord du pays qui ont un climat pluvieux et des températures modérées. Dans le sud, où le printemps et l'été sont habituellement chauds et secs, la jambe noire semble être réellement absente, même dans les champs plantés avec des tubercules provenant de régions infectées. Il a été établi que la transmission de la maladie d'une année à l'autre a lieu principalement par les tubercules infectés, le sol étant la source d'infection dans la seule mesure où il contient des restes non détruits de plantes malades. Il a été démontré que les bactéries perdent rapidement leur viabilité dans les sols non stériles (Tableau 1). Concernant l'étiologie de la jambe noire, on a trouvé que outreErwinia atroseptica que, jusqu'à présent, on croyait être la seule cause de la maladie en Roumanie,E. carotovora etE. aroideae jouent également un r?le important, spécialement pendant la conservation. Selon nos observations et expériences,E. atroseptica est le principal agent pathogène dans le champ, montrant une préférence marquée pour les tiges, tandis qu'apparaissent aussi les deux autres bactéries qui, toutefois, sont plus communément trouvées sur les tubercules pendant la conservation; à ce moment, sous des conditions favorables, les attaques de ces dernières peuvent être beaucoup plus grandes que celles deE. atroseptica. Les déterminations des comportements suivants se sont révélées pleinement utiles pour différencier les trois bactéries: les degrés d'attaques sur tiges et tubercules, les réactions sur sucres et spécialement leurs réactions sur maltose et sur milieu agar glucose peptone de grains trempés, leur développement à hautes températures (Tpableau 2) et leurs réactions sérologiques (Tpableau 3) aussi bien comme effets toxiques qu'immunologiques sur les animaux. Les résultats rapportés ici prouvent et développent les vues de ces chercheurs qui croient que les trois bactéries seraient à considérer comme espèces séparées.

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Paper read to the Pathology Section of the Second Triennial Conference of the European Association for Potato Research, Italy, September 1963.     

Effect of two thermal regimes on the muscle growth dynamics of sea bass larvae,Dicentrarchus labrax L

Muscle growth was studied in larvae of sea bass, Dicentrarchus labrax L., reared at two temperatures: real ambient temperature ( congruent with 15 degrees C during vitelline phase and increased gradually) and 19 degrees C from fertilization until the end of larval development. Muscle cellularity, body length and body weight were measured. Early temperature influenced larval development and so, pre-larval phase finished earlier at 19 degrees C than at ambient temperature (4 and 6 days, respectively). Temperature also affected muscle growth such that at hatching and at mouth opening hypertrophy of muscle fibres was greater at 19 degrees C (P < 0.05), whereas hyperplasia was similar in both groups. After 25 days, the cross-sectional area of the white muscle was greater at 19 degrees C (P < 0.05), which was mainly associated with a higher proliferation of new white muscle fibres. At this stage the body length was also higher at 19 degrees C. Metamorphosis finished earlier in fish reared at 19 degrees C (52 days) than at natural temperature (82 days). At this developmental stage body length and cross-sectional area of the myotome were similar in both groups. However, muscle cellularity differed between groups. Thus, hypertrophy of muscle fibres was higher in fish reared at ambient temperature (P < 0.05), whereas proliferation of new muscle fibres was higher at 19 degrees C (P > 0.05).     

Evaluation of 65% permethrin spot-on for prevention of canine visceral leishmaniasis: effect on disease prevalence and the vectors (Diptera: Psychodidae) in a hyperendemic area

A study was designed to examine the effect of 65% permethrin spot-on on the prevalence of canine visceral leishmaniasis and the abundance of sand flies in two neighborhoods in Corumbá, Mato Grosso do Sul, Brazil known to have a high prevalence of visceral leishmaniasis. An enrollment survey was conducted to determine the prevalence of visceral leishmaniasis. Area residents were provided with information about the project; the study area was defined, and all dogs (160 in Cristo Redentor and 230 in Popular Velha) identified in the study area were enrolled. Three 65% permethrin spot-on treatments (June 15-25, July 13-15, and August 10-12) were administered to 150, 110, and 99 dogs, respectively, in Popular Velha, according to label recommendations. Dogs in Cristo Redentor were untreated controls. Visceral leishmaniasis was diagnosed periodically by indirect immunofluorescence assay. A reduction in canine visceral leishmaniasis prevalence was observed at the Popular Velha site. The infection rate for treated dogs 1 month following the final treatment was approximately 50% reduced from that observed before treatment(19.3% vs 9.6%). Conversely, the infection rate at the control site was more than 80% higher at the September sampling than that observed pretreatment (4.1% vs 7.4%). Similar numbers of sand flies were captured and identified from both sites throughout the study. The results suggest that regular use of 65% permethrin during months of high risk for canine visceral leishmaniasis can be a useful strategy for reducing the prevalence of this disease in hyperendemic areas. It should be stressed, however, that the success of this strategy depends not only on the efficacy of the product itself but also on the adoption of other control measures and on economic variables, considering the low purchasing power of the populations living in higher-risk neighborhoods.