Structural modification of bacterial cellulose fibrils under ultrasonic irradiation

Ιn the present study we investigated ultrasounds as a pretreatment process for bacterial cellulose (BC) aqueous suspensions. BC suspensions (0.1–1% wt) subjected to an ultrasonic treatment for different time intervals. Untreated BC presented an extensively entangled fibril network. When a sonication time of 1 min was applied BC fibrils appeared less bundled and dropped in width from 110 nm to 60 nm. For a longer treatment (3–5 min) the width of the fibrils increased again to 100 nm attributed to an entanglement of their structure. The water holding capacity (WHC) and ζ-potnential of the suspensions was proportional to the sonication time. Their viscosity and stability were also affected; an increase could be seen at short treatments, while a decrease was obvious at longer ones. Concluding, a long ultrasonic irradiation led to similar BC characteristics as the untreated, but a short treatment may be a pre-handling method for improving BC properties

Carnosine:can understanding its actions on energy metabolism and protein homeostasis inform its therapeutic potential?

The dipeptide carnosine (β-alanyl-L-histidine) has contrasting but beneficial effects on cellular activity. It delays cellular senescence and rejuvenates cultured senescent mammalian cells. However, it also inhibits the growth of cultured tumour cells. Based on studies in several organisms, we speculate that carnosine exerts these apparently opposing actions by affecting energy metabolism and/or protein homeostasis (proteostasis). Specific effects on energy metabolism include the dipeptide's influence on cellular ATP concentrations. Carnosine's ability to reduce the formation of altered proteins (typically adducts of methylglyoxal) and enhance proteolysis of aberrant polypeptides is indicative of its influence on proteostasis. Furthermore these dual actions might provide a rationale for the use of carnosine in the treatment or prevention of diverse age-related conditions where energy metabolism or proteostasis are compromised. These include cancer, Alzheimer's disease, Parkinson's disease and the complications of type-2 diabetes (nephropathy, cataracts, stroke and pain), which might all benefit from knowledge of carnosine's mode of action on human cells. © 2013 Hipkiss et al.; licensee Chemistry Central Ltd

Structural and cytochemical investigation of the leaf of silverleaf nightshade (Solanum elaeagnifolium), a drought-resistant alien weed of the Greek flora

Light and scanning electron microscopy as well as histochemical reactions were employed to investigate the leaf structure and secretory activity of an adventive perennial pest that is rapidly dispersing in the Mediterranean region. Interesting structural characteristics, not common among the well-adapted native Mediterranean phanerophytes, were observed. Although 'unconventional', these structural characteristics produce an ecologically equivalent, xeromorphic leaf on a plant that proves to be competitive and very efficient under the Mediterranean climatic conditions. © CSIRO 2009