Early effects of boron deficiency on membrane function in higher plants

The transfer of plants to boron-free solutions induces rapid responses in membrane functions without necessarily affecting root growth and anatomy. In sunflowers (Helianthus annuus), root growth slows within 3-6 h. However in maize (Zea mays), no growth effects are apparent after more than 30 h without boron (-B). In both species early disturbances in ion uptake and cell wall deposition are seen. Ultrastructural studies on sunflower root tips after 5.5 h or 3 d -B are reported. Detailed studies on the absorption of Pj and K+ by root tips were complemented by studies on protoplasts isolated from the root tips of +B and -B plants. There were no significant differences in the protoplast yield or viability according to their B status. Ion absorption by protoplasts isolated from roots of +B and -B plants generally resembled that by intact roots of the corresponding B status. Altering the B status of the protoplasts was expected to initiate earlier responses than in the roots where cell wall binding and diffusion times buffer the system against change; but the greater variability inherent in measuring the protoplast responses prevented the detection of subtle changes. The activities of two+ membrane bound arjzymes were investigated; β-glucan synthetase and a K+-stimulated, Mg2+ -dependent ATPase. UDPG incorporation by protoplasts continued for over 18 h and was consistently higher in +B protoplasts and root membranes than -B. However SEM revealed no significant differences in fibre deposition around sunflower and maize protoplasts according to their boron status. (K++Mg2+)-ATPase from sunflower roots was found to be reversibly impaired by the loss of B; and preliminary investigations implied that restoration of activity when B was resupplied to the intact roots was correlated with the B content of the membrane fraction, as determined by the (n,α) method.</p

Biotransformation of glucosinolates from a bacterial perspective

Epidemiological studies have shown an association between the consumption of cruciferous vegetables and a reduced risk of certain types of cancers, in particular, pancreatic, bladder and colorectal. This is thought to be the result of the conversion of glucosinolates (GSLs) present in the vegetables into bioactive isothiocyanates (ITCs) that in turn stimulate a host response involving detoxification pathways. Conversion of GSLs is catalysed by the enzyme myrosinase, co-produced by the plant but stored in separate tissue compartments and brought together when the tissue is damaged. Myrosinase activity can be lost during storage of vegetables and is often inactivated by cooking. In the absence of active plant myrosinase the host's gut bacteria are capable of carrying out a myrosinase-like activity on GSLs in the lower gut. Several micro-organisms are known to be capable of metabolizing GSLs leading to the production of ITCs and nitriles, and this review examines the bacterial biotransformation of GSLs and a role for the microbiota in their biotransformation

Lactic acid bacteria convert glucosinolates to nitriles efficiently yet differently from enterobacteriaceae

Glucosinolates from the genus Brassica can be converted into bioactive compounds known to induce phase II enzymes, which may decrease the risk of cancers. Conversion via hydrolysis is usually by the brassica enzyme myrosinase, which can be inactivated by cooking or storage. We examined the potential of three beneficial bacteria, Lactobacillus plantarum KW30, Lactococcus lactis subsp. lactis KF147, and Escherichia con Nissle 1917, and known myrosinase-producer Enterobacter cloacae to catalyze the conversion of glucosinolates in broccoli extract. Enterobacteriaceae consumed on average 65% glucoiberin and 78% glucoraphanin, transforming them into glucoiberverin and glucoerucin, respectively, and small amounts of iberverin nitrile and erucin nitrile. The lactic acid bacteria did not accumulate reduced glucosinolates, consuming all at 30-33% and transforming these into iberverin nitrile, erucin nitrile, sulforaphane nitrile, and further unidentified metabolites. Adding beneficial bacteria to a glucosinolate-rich diet may increase glucosinolate transformation, thereby increasing host exposure to bioactives

Potential Role of Lycopene in the Prevention of Postmenopausal Bone Loss: Evidence from Molecular to Clinical Studies

Osteoporosis is a metabolic bone disease characterized by reduced bone mineral density, which affects the quality of life of the aging population. Furthermore, disruption of bone microarchitecture and the alteration of non-collagenous protein in bones lead to higher fracture risk. This is most common in postmenopausal women. Certain medications are being used for the treatment of osteoporosis; however, these may be accompanied by undesirable side effects. Phytochemicals from fruits and vegetables are a source of micronutrients for the maintenance of bone health. Among them, lycopene has recently been shown to have a potential protective effect against bone loss. Lycopene is a lipid-soluble carotenoid that exists in both all-trans and cis-configurations in nature. Tomato and tomato products are rich sources of lycopene. Several human epidemiological studies, supplemented by in vivo and in vitro studies, have shown decreased bone loss following the consumption of lycopene/tomato. However, there are still limited studies that have evaluated the effect of lycopene on the prevention of bone loss in postmenopausal women. Therefore, the aim of this review is to summarize the relevant literature on the potential impact of lycopene on postmenopausal bone loss with molecular and clinical evidence, including an overview of bone biology and the pathophysiology of osteoporosis

Pharmacokinetic Benefits of 3,4-Dimethoxy Substitution of a Phenyl Ring and Design of Isosteres Yielding Orally Available Cathepsin K Inhibitors

Rational structure-based design has yielded highly potent inhibitors of cathepsin K (Cat K) with excellent physical properties, selectivity profiles, and pharmacokinetics. Compounds with a 3,4-(CH₃O)₂Ph motif, such as <b>31</b>, were found to have excellent metabolic stability and absorption profiles. Through metabolite identification studies, a reactive metabolite risk was identified with this motif. Subsequent structure-based design of isoteres culminated in the discovery of an optimized and balanced inhibitor (indazole, <b>38</b>)