Effects of Ruta graveolens leaves on soil characteristics and on seed germination and early seedling growth of four crop species

Effects of rue (Ruta graveolens) leaves on soil characteristics and on germination and seedling growth of four crop species (radish, zucchini, cauliflower and tomato) were investigated. Soil not previously associated with rue was mulched and amended with its fresh leaves. The objectives of the present study were to determine: (i) the changes in soil chemical characteristics after addition of rue leaves, (ii) the growth responses in soils treated with R. graveolens leaves, and (iii) whether the soil chemistry changes affect plant growth. Results indicate that soil incorporated with rue leaves had higher values of water‐soluble phenolics, electrical conductivity and nitrate, and lower pH values compared to untreated soil. Seed germination of radish and tomato was suppressed in covered and amended soils compared to control soil. Seedling development for all the species was suppressed in incorporated and amended soil, compared to the rue‐free soil. Correlations between soil chemical characteristics, germination and seedling growth of plants are also discussed.     

Reproductive biology of the East African lungfish (Protopterus aethiopicus) in Mwanza Gulf, Lake Victoria

The population of lungfish (Protopterus aethiopicus (Heckel)) was sampled by bottom trawling for 12 months from June 1984 to May 1985. A total of 576 lungfish were investigated. The sex ratio in the population was 1 male : 1 -98 females. Average size at maturity was found to be 960cm total length (TL) but the smallest matured male measured 72-9 cm and the female 840 cm TL. It was not possible to establish spawning times and reproductive activity trends either from the variation in relative condition factor ‘kn’ or from gonadosomatic index (GSI). Whereas male lungfish seem to show no further increase in GSI after gonadal maturity stage III, females exhibit GSI values that vary directly with oocyte maturation and ovarian weights. Fat deposited along the gonads was found to be a better basis for assessing maturation and spawning in lungfish. The potential spawning period was found to be from September to May. Absence of lungfish with spent gonads over the 12-month period and the presence of different egg sizes in ovaries, suggest that the fish is a multiple spawner. Fecundity was found to range from 705 eggs (in 84-cm TL fish) to 14,922 eggs (in 130-cm TL Fish).     

The recombinant protein rSP03B is a valid antigen for screening dog exposure to Phlebotomus perniciosus across foci of canine leishmaniasis

The frequency of sandfly–host contacts can be measured by host antibody levels against sandfly salivary proteins. Recombinant salivary proteins are suggested to represent a valid replacement for salivary gland homogenate (SGH); however, it is necessary to prove that such antigens are recognized by antibodies against various populations of the same species. Phlebotomus perniciosus (Diptera: Psychodidae) is the main vector of Leishmania infantum (Trypanosomatida: Trypanosomatidae) in southwest Europe and is widespread from Portugal to Italy. In this study, sera were sampled from naturally exposed dogs from distant regions, including Campania (southern Italy), Umbria (central Italy) and the metropolitan Lisbon region (Portugal), where P. perniciosus is the unique or principal vector species. Sera were screened for anti‐P. perniciosus antibodies using SGH and 43‐kDa yellow‐related recombinant protein (rSP03B). A robust correlation between antibodies recognizing SGH and rSP03B was detected in all regions, suggesting substantial antigenic cross‐reactivity among different P. perniciosus populations. No significant differences in this relationship were detected between regions. Moreover, rSP03B and the native yellow‐related protein were shown to share similar antigenic epitopes, as canine immunoglobulin G (IgG) binding to the native protein was inhibited by pre‐incubation with the recombinant form. These findings suggest that rSP03B should be regarded as a universal marker of sandfly exposure throughout the geographical distribution of P. perniciosus.     

Diurnal cycles in microhabitat use by forest passerines: consequences for community structure

Time of day is usually not considered an important factor underlying the structure of forest passerine communities. However, this study shows that the positions exploited in trees by some members of a community change during the day in a cyclic pattern. Coal Tit Pants ater, Crested Tit Parus cristatus and Goldcrest Regulus regulus foraged lower and nearer to the trunk at midday than in the first and last hours of the day. Simultanously, there were diurnal changes in the niche breadth (degree of uniformity in the exploitation of the different parts of the trees). The Coal Tit reached the maximum niche breadth values during the central part of the day, with the minimum being recorded at that time for the Crested Tit and the Goldcrest. On the other hand, Treecreepers Certhia sp. did not show significant diurnal variation. These results, together with the changes in activity levels during the day for each species, suggest that time of day plays an important role in the structure of the community, allowing a more uniform use of the habitat and addressing a new interpretation of the interspeciic relationships inside the community, with competitive relationships not showing the same intensity throughout the day.     

Emerging Applications of Bacteriocins as Antimicrobials,Anticancer Drugs,and Modulators of The Gastrointestinal Microbiota

The use of bacteriocins holds great promise in different areas such as health, food, nutrition, veterinary, nanotechnology, among others. Many research groups worldwide continue to advance the knowledge to unravel a novel range of therapeutic agents and food preservatives. This review addresses the advances of bacteriocins and their producer organisms as biocontrol agents for applications in the medical industry and agriculture. Furthermore, the bacteriocin mechanism of action and structural characteristics will be reviewed. Finally, the potential role of bacteriocins to modulate the signaling in host-associated microbial communities will be discussed.