Fluorescence of Extracts from Argentine Hake (Merluccius hubbsi) Muscle and Its Correlation with Quality Indices During Chilled Storage

Argentine hake (Merluccius hubbsi) was stored chilled for 8 days. The evolution of fluorescence of the aqueous and organic extracts of muscle during storage at 4°C was studied and correlated with common damage indices; pH, total volatile basic nitrogen, free fatty acids, and the fluorescence intensity of the aqueous phase showed a good correlation with storage time. The excitation-emission matrices of the aqueous extracts were also obtained. A fluorescence landscape that could be attributed to tryptophan decreased with storage time, meanwhile a peak (around 340 and 400 nm for excitation and emission wavelengths, respectively) is developed during chilled storage.     

Effect of indigenous mycorrhizal colonization on phosphorus‐acquisition efficiency in soybean and sunflower

Despite a general consent about the beneficial contribution of arbuscular mycorrhizal fungi (AMF) on natural ecosystems, there is an intense debate about their role in agricultural systems. In this work, soybean (Glycine max L.) and sunflower (Helianthus annuus L.) field plots with different P availabilities were sampled across the Pampean Region of Argentina (> 150 samples from Mollisols) to characterize the relationship between available soil P and indigenous mycorrhizal colonization. A subsequent pot experiment with soybean and sunflower was carried out to evaluate the effect of P supply (0, 12, and 52 mg P kg^–1) and AMF inoculation on AMF colonization and crop responsiveness to P in a Mollisol. Both crops showed high AMF colonization in the field (average: 55% for soybean and 44% for sunflower). While mycorrhizal colonization in soybean was significantly and negatively related to available soil P, no such trends were apparent in sunflower. Also, total biomass was 3.5 and 2.0 times higher in mycorrhizal than in nonmycorrhizal pot‐grown soybean under low‐ and medium‐P conditions, respectively. Sunflower, on the other hand, did not benefit from AMF symbiosis under medium and high P supply. While mycorrhization stimulated P‐uptake efficiency in soybean, the generally high P efficiency in sunflower was not associated with AMF symbiosis.     

Precision agriculture research in sub-Saharan Africa countries: a systematic map

Precision agriculture (PA) has a huge potential for growth in sub-Saharan Africa (SSA), but it faces a number of social-economic and technological challenges. This study sought to map existing PA research and application in SSA countries following the methodology for systematic mapping in environmental sciences. After screening for relevance, the initial about 7715 articles was reduced to 128. Results show that most of the studies were conducted in countries with socio-economic and technological advancement, mainly South Africa followed by Nigeria and Kenya. The studies were conducted at various scales ranging from field to country level with field scale studies being the most common. Most studies were conducted in relatively small farms typical of most farmlands in SSA. Studies done in relatively large farms are fewer, and such farms would likely belong to a few organisations and individuals with high economic capacity. Many of these studies have been conducted by researchers from outside SSA and a combination of researchers from within and outside SSA. However, based on authorship of the articles, it appears that most of the studies conducted in SSA on precision agriculture have either involved or depended on non-African researchers. It is concluded that there have been significant strides towards use of precision agriculture in SSA. However, with about 21 countries having no research done, there exists greater potential for precision agriculture in the region. Besides, there is need for more research to investigate the low usage of precision agriculture for livestock management.

     

The Bioavailability of Copper and Mercury to the Common Nettle (Urtica Dioica) and the Earthworm Eisenia Fetida from Contaminated Dredge Spoil

The contaminants Hg and Cu, as well as Fe, Mn and K were sequentially extracted from upland disposed dredge spoil using DTPA and 10% nitric acid. Concentrations of these metals in aerial plant tissue and roots of Urtica dioica growing on the dredge spoil were also determined and used to correlate the biological absorption coefficients (BACs) and mobile element absorption coefficients (MACs) with soil extractable metals. DTPA extractions were most suitable for prediction of aerial plant tissue uptake of Cu, Mn and K whilst total Hg and Fe soil concentrations were correlated with plant root BACs and MACs. A laboratory bioassay using Eisenia fetida was also used to assess the potential biological uptake of the contaminants. Both Hg and Cu were accumulated by the worms, but interpretation of the results was hampered by the inherent difficulties of such active biomonitoring.     

Activity parameters relative to habitat in four southern African tree squirrels

Activity measurements were aimed at quantifying the most obvious interspecific differences. Analyses of variance were made on the parameters of tai If licking, grooming, movement, murmuring, time spent motionless and time spent feeding. The two species from open habitats, Paraxerus c. cepapi and Funisciurus congicus have a lower level of activity than the two subspecies from forested habitat, P. palliatus ornatus and P.p. tongensis. The former two species move less frequently and over shorter distances. The largest species P.p. ornatus is the most active. The two forest subspecies are more efficient in handling food and feeding. The two open habitat species allogroom more frequently than selfgroom when compared to the forest subspecies. This is related to a closer group structure.     

Occurrence of Equine Coital Exanthema in Mares from an Embryo Transfer Center

Equine coital exanthema (ECE) is an acute, venereal disease caused by equid herpesvirus 3 (EHV-3), characterized by the formation of papules, vesicles, pustules, and ulcers on the vaginal and vestibular mucosa as well as on the skin of the penis, prepuce, and perineal region of mares and stallions. The present work describes an outbreak of ECE characterized by typical lesions around the anus and on the perineal skin, discomfort, and anorectal lymphadenopathy, which occurred in a large number of donor and recipient mares at an embryo transfer center in Argentina. We found that the horses' movement pattern, the environmental conditions, and the management procedures could have favored the introduction and/or reactivation from latency and spread of EHV-3. Although this is the first report of an outbreak of ECE in an embryo transfer facility, it reinforces the need to introduce additional hygienic and preventive measures to avoid EHV-3 spread and future ECE outbreaks.