Salmonellosis detection and evidence of antibiotic resistance in an urban raccoon population in a highly populated area,Costa Rica

Wild animals are involved in zoonotic disease transmission cycles. These are generally complex and poorly understood, especially among animals adapted to life in human ecosystems. Raccoons are reservoirs and effective carriers for infectious agents such as Salmonella throughout different environments and contribute to the transference of resistance genes. This study examined the presence of circulating Salmonella sp. in a population of raccoons in a tropical urban environment and evaluated resistance to antibiotics commonly used to treat salmonellosis. A total of 97 raccoons of different ages and sex were included in this study. 49% (38–60 CI) of the faecal samples were positive for Salmonella spp. The study identified 15 circulating serovars with the most prevalent being S. Hartford (7/15), S. Typhimurium (4/15) and S. Bovismorbificans (4/15). These serovars correspond to the serovars detected in humans with clinical symptoms in Costa Rica. 9.5% of the Salmonella strains recovered demonstrated ciprofloxacin resistance, and 7.1% showed resistance to nalidixic acid. This study provides evidence of multiple Salmonella serovars circulating in a population of urban raccoons in Costa Rica. Furthermore, the study confirms the existence of antimicrobial resistance to two antibiotics used to treat human salmonellosis. The findings emphasize the role of the raccoon as a reservoir of Salmonella in the Greater Metropolitan Area of Costa Rica (GAM) and stress the need for active monitoring of the presence and possible spread in antibiotic resistance due to this peri‐domestic carnivore.     

Zur Wirkung von Niemprodukten aufBemisia tabaci Genn. an Auberginen bei Verwendung verschiedener Zusatzstoffe

As neem (Azadirachta indica A. Juss.) seed is still quite expensive in the Dominican Republic, it was tried to reduce the dosage by increasing the efficiency of the insecticide using the adjuvant Tersan (Alcohol-9-ethylen-oxid).The effect of various aqueous neem seed extracts (25 g seeds per 1, 40 g/l, 60 g/l, oilcake 15 g/l) and formulated neem oil mixed with the adjvant was tested in laboratory and field trials againstBemisia tabaci on eggplant. In laboratory trials the efficiency of all tested products except neem oil was increased by 24% to 48%. The increase of efficiency was more pronounced on very hairy than on glabrous plants. These positive results could not be confirmed in field trials, where the adjuvant had no effect or even reduced the efficiency of the insecticide.The effect of the adjuvant is a reduction of the surface tension of the spraying mixture for better wetting and to adhere it to the leaf. As the laboratory plants usually possessed much more hairs than those in the field, the insecticide could develop its full effect in the field even without support by the adjuvant.

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Zur Wirkung von Niemprodukten aufBemisia tabaci Genn. an Auberginen bei Verwendung verschiedener Zusatzstoffe

Zusammenfassung Eine Verringerung der Dosis von Niemprodukten kann mitunter zu einer signifikanten Minderung des Wirkungsgrades und zu Ernteverlusten führen. Geringer Befall sollte aber immer auch mit einer Dosis unterhalb der empfohlenen 50 g Samenpulver pro Liter Wasser bekämpfbar sein. Der Zusatz von Stoffen, die eine bessere Benetzung der Pflanze gewährleisten, zu Niemsamenwasserextrakten führte im Labor bei wenig behaarten Auberginenpflanzen kaum zu Wirkungssteigerungen gegenüberB. tabaci. Bei stark behaarten Pflanzen jedoch konnte die Effektivität um bis zu 90% gesteigert werden, da die Behaarung eine Benetzung der Blattspreite und damit eine Wirkung verhindert. Im Feld konnten Wirkungssteigerungen durch Zusatz von Netzmitteln nicht erreicht werden. Im Gegenteil: Die Wirkung der wässrigen Niemsamenextrakte wurde oft aus unerklärlichen Gründen herabgesetzt. Die Wirkung von Niemöl konnte weder im Feld- noch im Laborversuch durch Zusatzstoffe gesteigert werden.

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Mit 3 Abbildungen     

Sap flux – a real time assessment of health status in Norway spruce

Top dieback of Norway spruce (Picea abies), triggered by drought in 2004–2006, has been observed in Southeast Norway and trees died within four years after appearance of the first symptoms. The aim of our study was to use sap flux measurements as a diagnostic method for assessment of tree vitality. We used the heat field deformation method to monitor the sap flux density (SFD) in four pairs of healthy and declining trees in situ. To provide retrospective information on hydraulic performance of the trees we took samples for wood anatomical analysis. After felling the trees we used the modified differential translucence method (MDT) as a proxy for the SFD measurements. Healthy trees had three times higher SFD values as declining trees. In some healthy trees we detected decreasing SFD with time. The MDT method agreed with the SFD measurements. In conclusion, we detected sap flux dysfunction in declining trees and showed that the SFD reduction may occur during a short period, prior to occurrence of any visual symptoms. We suggest incorporating the SFD measurements into the repertoire of diagnostic tools in forest pathology.     

Lumbricid associations on a former open clay pit after recultivation with different tree species

The earthworm fauna was recorded from a former open clay pit five and seven years after the area had been recultivated with various tree species. The highest abundances (200–245 specimens/m²) and biomasses (46.8 to 48.4 g/m²) were found in the following stand types: mixed woodland of balsam poplar (various sorts) and grey alder (Alnus incana (L.)Moench), mixed woodland of balsam poplar (Andoscoggin) and black alder (Alnus glutinosa (L.)Gaertn.), and a pure stand of black alder. Clearly lower values were found in a plot with common oaks (Quercus robur L.) under a dense shelterwood of naturally regenerated willows (Salix spec.), and a plot exclusively stocked with naturally regenerated willows. The rapid resettlement of the backfilled, compacted clay soil is above all explained by the high pH-values found in the surface soil. The differences between the studied plots regarding total abundance and biomass might be explained by the different qualities and amounts of litter. The highest species diversity — expressed by the Shannon-index — and the highest proportion of endogeic species, particularlyAporrectodea caliginosa Savigny 1826, were calculated for the two stands with a mixture of alder and balsam poplar. This result could have been caused by the lack of parent soil bed and the particularly high pH-value of the soils found there.     

Structural constituents of the seagrass Posidonia australis

Large amounts of seagrass, Posidonia australis, wash onto beaches in South Australia each year, causing substantial environmental problems. It was of interest to assess the potential for an economic use of this seagrass-such as for animal nutrition. Structural constituents of P. australis (green, freshly deposited, and both washed and unwashed samples from dried deposits on the beach) were examined and compared. Glucose, galactose, and mannose were the dominant sugars (>10 g kg-1 of dry matter) in the soluble fraction of nonstarch polysaccharides in all seagrass forms. The content of the insoluble constituents of the nonstarch polysaccharides was significantly higher than soluble nonstarch polysaccharide constituents (P < 0.01). Data showed that the major constituents of the Posidonia cell wall are cellulose and lignin (190-209 and 145-154 g kg-1, respectively). The crude protein content of Posidonia ranged from 54 to 61 g kg-1. Results showed no biologically significant compositional differences between the four different forms of seagrass tested. Dry, unwashed seagrass, which is readily available in large quantities and easily harvested, may have potential as a foodstuff for ruminant animals.     

Structure of the 70S ribosome complexed with mRNA and tRNA

The crystal structure of the bacterial 70S ribosome refined to 2.8 angstrom resolution reveals atomic details of its interactions with messenger RNA (mRNA) and transfer RNA (tRNA). A metal ion stabilizes a kink in the mRNA that demarcates the boundary between A and P sites, which is potentially important to prevent slippage of mRNA. Metal ions also stabilize the intersubunit interface. The interactions of E-site tRNA with the 50S subunit have both similarities and differences compared to those in the archaeal ribosome. The structure also rationalizes much biochemical and genetic data on translation.