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Lactic acid bacteria (LAB) are widely known for their probiotic activities for centuries. These bacteria synthesise some secretory proteinaceous toxins, bacteriocins, which help destroy similar or interrelated bacterial strains. This study was aimed at characterising bacteriocins extracted from Lactobacillus spp. found in yoghurt and assessing their bactericidal effect on foodborne bacteria. Twelve isolated Lactobacillus spp. were examined to produce bacteriocins by the organic solvent extraction method. Bacteriocins produced by two of these strains, Lactobacillus helveticus (BLh) and Lactobacillus plantarum (BLp), showed the most significant antimicrobial activity, especially against Staphylococcus aureus and Acinetobacter baumannii. Analysis of SDS-PAGE showed that L. plantarum and L. helveticus bacteriocins have a molecular weight of ~10 kDa and ~15 kDa, respectively. L. plantarum (BLp) bacteriocin was heat stable while L. helveticus (BLh) bacteriocin was heat labile. Both bacteriocins have shown activity at acidic pH. Exposure to a UV light enhances the activity of the BLh; however, it had negligible effects on the BLp. Different proteolytic enzymes confirmed the proteinaceous nature of both the bacteriocins. From this study, it was concluded that bacteriocin extracts from L. helveticus (BLh) can be considered a preferable candidate against foodborne pathogens as compared to L. plantarum (BLp). These partially purified bacteriocins should be further processed to attain purified product that could be useful for food spoilage and preservation purposes.

Proceedings of the Transportation Research Forum – 24th – 1983 (Presented at the 18th Canadian Transportation Research Forum meeting, Regina, Saskatchewan, June 1983)

The progressive increase in the earth’s temperature due to anthropogenic activities is a major concern for humanity. The ensuing heat stress (HS) severely impacts plant growth, endangering ecosystem quality and world food security. Plant growth, physiological processes and final amount of edible products are affected by HS to an extent that reflects the physical damages, physiological commotions and biochemical alterations incurred at various growth stages. Therefore, a better understanding of plant behaviour in response to HS has pragmatic implications for devising counter-measures, alleviation strategies, and for acknowledging the differences between HS and the companion drought stress. Conventional breeding, biotechnological and molecular approaches are used to develop HS tolerant genotypes in plant species bred for food/feed uses. Recent achievements in the omics techniques result in a better knowledge of the molecular mechanisms involved in HS. However, shrewd management of crop practices is still helpful to improve plant resilience to HS. Suitable sowing time, seed priming, bacterial seed treatment, nutrient and water management, exogenous application of osmo-protectants, and conservation of soil moisture are important tools to improve plant behaviour under the critical HS scenarios determined by climate change and global warming.

Soil salinity threatens agricultural production worldwide by constraining plant growth and final crop yield. The early stages are most sensitive to salinity, in response to which salicylic acid (SA) has demonstrated beneficial effects in various plant species. Based on this, a maize (Zea mays L.) pot experiment was set up combining three levels of soil salinity (0, 6 and 12 dS m–1), obtained through NaCl addition, with three levels of SA (0, 300 and 600 mM), applied by leaf spraying 20 days after seedling emergence. Fifteen days later, the following traits were assessed: morphology (plant height, leaf number), growth (root and shoot dry weight), leaf water status [relative water content (RWC), electrolyte leakage (EL)], pigments (chlorophyll a and b, carotenoids, anthocyanin), antioxidant enzymes (peroxidase, catalase, ascorbate peroxidase, vitamin C), oxidative stress markers (H2O2, malondialdehyde), osmo-regulating compounds (free amino acids, soluble proteins and sugars, proline), hormones [indole-3-acetic acid, gibberellic acid (GA), abscisic acid (ABA), ethylene], element (Na, K, Ca, Mg and Cl) concentration and content in roots, stem and leaves. Salinity severely affected maize growth (–26% total dry weight), impaired leaf water status (–31% RWC), reduced photosynthetic pigments, enhanced all antioxidant enzymes and oxidative stress markers, two osmo-regulating compounds (soluble sugars and proline) out of four, and all hormones except GA. SA was shown effective in containing most of the stress effects, while supporting plant defences by upgrading antioxidant activities (reduced oxidative stress markers), increasing cell membrane stability (–24% EL) and leaf water status (+20% RWC), and reducing plant stress signalling (–10% ABA and -20% ethylene). Above all, SA contrasted the massive entry of noxious ions (Na+ and Cl–), in favour of K+, Ca2+ and Mg2+ accumulation. Lastly, salicylic acid was shown beneficial for maize growth and physiology also under non-saline condition, suggesting a potential use in normal field conditions. Highlights - Foliar applied salicylic acid alleviated salinity effects on maize growth at early plant stage. - Salicylic acid improved leaf water status, chlorophyll content, and strengthened anti-oxidant enzymes under salinity. - Salicylic acid reduced oxidative stress markers while enhancing osmo-regulating and hormonal responses to salinity. - Salicylic acid hampered Na and Cl entry and translocation to above ground organs, preserving leaf cell membrane integrity. - Salicylic acid was shown beneficial for maize growth and physiology also under non-saline conditions.

Drought stress affects plant growth and development by altering physiological and biochemical processes resulting in reduced crop productivity. Zinc (Zn) is an essential micronutrient that plays fundamental roles in crop resistance against the drought stress by regulating various physiological and molecular mechanisms. Under drought stress, Zn application improves seed germination, plant water relations, cell membrane stability, osmolyte accumulation, stomatal regulation, water use efficiency and photosynthesis, thus resulting in significantly better plant performance. Moreover, Zn interacts with plant hormones, increases the expression of stress proteins and stimulates the antioxidant enzymes for counteracting drought effects. To better appraise the potential benefits arising from optimum Zn nutrition, in the present review we discuss the role of Zn in plants under drought stress. Our aim is to provide a complete, updated picture in order to orientate future research directions on this topic.

Biomass sorghum increasingly constitutes the feedstock for methane production. Optimization of crop management for this use is far from being achieved under warm dry climate. To fill the gap of knowledge, five cultivars of Sorghum bicolor were cross combined with three seeding times (ST) at 20-day intervals from 1st May 2016 and 2017, in a field experiment conducted in Pakistan. Late vs. early seeding determined a 23% loss in dry biomass yield (DBY), but no variation in specific methane yield (SMY). Therefore, methane yield per hectare (MY), their product, staged a 22% loss with late vs. early seeding, reflecting DBY loss. Biometric and compositional changes were shown in late vs. early seeding: smaller plants with lower protein, sugar and fibre content, associated with a hastening in crop development despite non-limiting ambient conditions until maturity. This comprehensive effect explains the yield reductions incurred by late seeding in this and other studies where irrigation could fully compensate lack of precipitation during crop growth. The five cultivars, three of which being dual-purpose genotypes (grain and biomass), and the other two fibre genotypes, staged significant DBY, SMY and MY differences (-28%, -14% and -16%, respectively) between worst and best performing cultivar. Significant seeding time × cultivar interactions indicate a slight advantage across seeding times for dual-purpose vs. fibre genotypes in DBY, whereas in MY none of the two groups clearly prevailed. Results obtained in this experiment complement previous outcomes with cultivars and harvest times, supporting bio-energy growth under warm dry climatic conditions.