Root-associated fungi of healthy-looking Pinus sylvestris and Picea abies seedlings in Swedish forest nurseries

The aim of this study was to assess fungal communities in roots of healthy-looking Pinus sylvestris L. and Picea abies (L.) Karst. seedlings in nine forest nurseries in Sweden using a combination of traditional culturing and direct sequencing of internal transcribed spacer of fungal ribosomal RNA (ITS rRNA) from the roots. Culturing from 1800 surface-sterilised root segments resulted in 2387 fungal cultures representing 42 different taxa. Direct sequencing from 180 root segments resulted in 119 ITS rRNA sequences representing 25 different taxa. In total, 55 different fungal taxa were detected using both methods. Although direct sequencing was more efficient than culturing in detecting different fungal taxa, both methods provided complementary information about fungal communities in roots since each detected rather different groups of fungi. The most dominant taxa detected by culturing were Trichoderma viride Pers. (19.5%), Phoma mucivora Davey & Currah (19.1%), Phialocephala fortinii Wang & Wilcox (17.4%) and Meliniomyces variabilis Hambl. & Sigler (10.2%), while Thelephora terrestris Ehrh. (26.1%), Unidentified sp. NS126 (25.2%) and Heliotales sp. C20 (10.1%) were most commonly detected by direct sequencing. In conclusion, results showed that forest nurseries in Sweden harbour diverse communities of fungi associated with the roots of healthy-looking P. sylvestris and P. abies seedlings. Although fungal communities were often dominated by saprotrophs and endophytes, several facultative pathogens were also detected indicating that under suitable conditions they may be a potential threat to the plants.     

A new source of cytoplasmic male sterility in sunflower

Summary Interspecific substitutions of the nucleus of Helianthus annuus (2n=34) cv. Saturn into the cytoplasm of H. petiolaris (2n=34) by successive backcrossing, resulted in progenies with indehiscent anthers containing white, rather than normal yellow, pollen. Further backcrossing by cv. Saturn failed to restore pollen shed, suggesting that the male sterility was cytoplasmic. In vivo germination tests of pollen from 23 such plants from eight BC₅ lines, indicated complete pollen sterility for 14 plants, but normal seed set, suggesting that female fertility was not affected. Meiosis in all plants examined was normal.Crosses between seven sources of pollen-fertility restorer, one collection of wild H. annuus, and an existing source of cytoplasmic male sterility, resulted in a high frequency of plants with normal pollen shed in all F₁ progenies. However, no normal pollen shed was evident in F₁ progenies for similar crosses between BC₅ male-steriles and three of the seven restorer sources, nor for the single wild H. annuus evaluated. The foregoing suggests that the backcross substitution lines are a new source of cytoplasmic male sterility. The inheritance of restoration of pollen shed was complex and not fully elucidated. Some data suggested that two independent, complementary, dominant genes were required, but others indicated two to three independent, dominant genes.     

The crystal structure of a sodium galactose transporter reveals mechanistic insights into Na+/sugar symport

Membrane transporters that use energy stored in sodium gradients to drive nutrients into cells constitute a major class of proteins. We report the crystal structure of a member of the solute sodium symporters (SSS), the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT). The approximately 3.0 angstrom structure contains 14 transmembrane (TM) helices in an inward-facing conformation with a core structure of inverted repeats of 5 TM helices (TM2 to TM6 and TM7 to TM11). Galactose is bound in the center of the core, occluded from the outside solutions by hydrophobic residues. Surprisingly, the architecture of the core is similar to that of the leucine transporter (LeuT) from a different gene family. Modeling the outward-facing conformation based on the LeuT structure, in conjunction with biophysical data, provides insight into structural rearrangements for active transport.     

Polychlorinated biphenyl uptake and translation by Spartina alterniflora loisel

This paper presents the findings of initial investigation of the role of Spartina alterniora Loisel. in the movement of chlorinated hydrocarbons. ¹⁴C-polychlorinated biphenyls and technical Aroclor® 1254 were used for the determinations. The findings demonstrate that Spartina accumulates ¹⁴C-radioactivity from sand and organic mud soil systems treated with ¹⁴C-PCB's. These findings also demonstrate that this plant has the capacity to accumulate ¹⁴C-radioactivity to levels elevated above that in the treated soil. Other experiments with Aroclor® 1254 demonstrate that cogeners of Aroclor® 1254 are present in Spartina stem and root extracts. These experiments also suggest that the chlorinated hydrocarbon uptake process is modulated by the plant and that this results in selective cogener uptake. The selectivity appears to be for the lesser chlorinated components of the commercial mixture. Overall, this study suggests that Spartina may act as an initial vector for mobilization of sediment bound chlorinated hydrocarbons to the estuarine food chain.     

Bilateral optic nerve hypoplasia in a pup.

A 6-week-old Beagle failed to respond to visual stimulation. Examination revealed fixed dilated pupils and hypoplasia of both optic disks. Results of electroretinography were normal. Radiography of the skull revealed small optic nerve foramina. Histologically, the outer layers of the retinas were normal, the retinal ganglion cells were scarce, and the nerve fiber layers, optic nerves, and optic chiasm were hypoplastic.     

The effect of plant extracts as seed treatments to control bacterial leaf spot of tomato in Tanzania

Bacterial leaf spot (BLS) caused by seed-borne xanthomonads is a serious disease of tomato (Solanum lycopersicum L.), causing significant losses in both yield and quality. To identify more effective control measures, we evaluated crude extracts from 84 plant species in in vitro and in planta assays for antibacterial activity against BLS of tomato. In the in vitro assays, 20.2?% of the tested plant extracts totally inhibited growth of bacteria when seed washings from treated seeds were plated on nutrient agar medium. In the in planta assays, 17.8?% of the tested plant extracts reduced BLS incidence by 100?% in tomato seedlings. The most effective seed treatments were obtained with extracts from Aloe vera, Betula pendula, Coffea arabica, Glycyrrhiza uralensis, Juniperus communis, Ocimum basilicum, Quercus robur, Rheum palmatum, Rosmarinus officinalis, Ruta graveolens, Sinapis alba, Yucca schidigera and Salvia officinalis. Seed treatment of tomato with these extracts completely inhibited Xanthomonas perforans in both in vitro and in planta assays. Extracts from A. vera, C. arabica and Y. schidigera were tested three times using tomato seeds of cultivars Tanya, Cal-J and Moneymaker in Tanzania. Treatment of tomato seeds with these extracts had a positive effect on the number of normal seeds and had no effect on seedling vigor, height and weight. These results indicate that plant extracts from A. vera, C. arabica and Y. schidigera are potential candidates for seed treatment against seed-borne xanthomonads of tomato in Tanzania.     

Evaluating a group-based intervention to improve the safety of meat in Bodija Market,Ibadan, Nigeria

We evaluated a group-based, participatory training intervention to improve food safety among meat processors and retailers in Bodija Market, Ibadan, Nigeria. An interactive training workshop was held for Butchers Associations’ representatives who were selected to pass on information and training to their group. Meat hygiene knowledge, attitude and practice was assessed before attending the workshop and afterwards (n = 63). It was also assessed for those who did not attend the workshop (n = 68) but were intended recipients of training through their association. Microbiological quality of meat was assessed before and after the workshop (n = 400 samples). After the workshop, participants significantly improved knowledge, attitude and practice in key food safety aspects; specifically, understanding sources of contamination and food-borne diseases, use of bleach and disinfectant and hand washing. Participants also shared information with an average of 18 other group members and improvements were seen in group members who did not attend the workshop but received training through their Butchers Association. Microbiological quality of meat sold also significantly improved after the intervention. In conclusion, participatory, group-based methods targeted at meat processors and retailers can improve meat hygiene knowledge, attitude and practice as well as the microbiological quality and hence safety of meat.