Localised expression of OsIAA29 suggests a key role for auxin in regulating development of the dorsal aleurone of early rice grains.

MAIN CONCLUSION: Non-canonical AUX/IAA protein, OsIAA29, and ZmMPR-1 homologues, OsMRPLs, are part of an auxin-related signalling cascade operating in the dorsal aleurone during early rice grain development. Endosperm of rice and other cereals accumulates high concentrations of the predominant in planta auxin, indole-3-acetic acid (IAA) during early grain development. However, IAA signalling and function during endosperm development are poorly understood. Here, we report that OsYUC12 (an auxin biosynthesis gene) and OsIAA29 (encoding a non-canonical AUX/IAA) are both expressed exclusively in grains, reaching a maximum 5-6 days after pollination. OsYUC12 expression is localised in the aleurone, sub-aleurone and embryo, whereas OsIAA29 expression is restricted to a narrow strip in the dorsal aleurone, directly under the vascular bundle. Although rice has been reported to lack endosperm transfer cells (ETCs), this region of the aleurone is enriched with sugar transporters and is likely to play a key role in apoplastic nutrient transfer, analogous to ETCs in other cereals. OsIAA29 has orthologues only in grass species; expression of which is also specific to early grain development. OsYUC12 and OsIAA29 are temporally co-expressed with two genes (AL1 and OsPR602) previously linked to the development of dorsal aleurone or ETCs. Also up-regulated at the same time is a cluster of MYB-related genes (designated OsMRPLs) homologous to ZmMRP-1, which regulates maize ETC development. Wheat homologues of ZmMRP-1 are similarly expressed in ETCs. Although previous work has suggested that other cereals do not have orthologues of ZmMRP-1, our work suggests OsIAA29 and OsMRPLs and their homologues in other grasses are part of an auxin-regulated, conserved signalling network involved in the differentiation of cells with ETC-like function in developing cereal grains.

Docosahexaenoic Acid (DHA, C22:6, ω-3) Composition of Milk and Mammary Gland Tissues of Lactating Mother Rats Is Severely Affected by Lead (Pb) Exposure.

Docosahexaenoic acid (DHA, C22:6, ω-3), an ω-3 polyunsaturated fatty acid (PUFA), is critical for brain growth, development, and cognitive ability. It is consumed by offspring via milk during lactation. However, the toxic heavy metal lead (Pb) readily passes into the mammary glands of mother animals and then to offspring through milk. Here, we investigated whether DHA composition of milk and mammary gland tissues is affected by Pb exposure. Mother rats were exposed to Pb via drinking water (0.1%). The fatty acid profile and levels of reduced glutathione (GSH), lipid peroxide (LPO), and pro-inflammatory TNF-α in milk and mammary tissues were measured. Levels of DHA and antioxidant GSH decreased (P < 0.05), while LPO and TNF-α levels increased (P < 0.05) both in milk and mammary tissues. Our results suggest that toxic Pb exposure can upset the level of milk DHA, which may affect brain growth and development, and hence cognitive ability in adulthood and later life.

Cholesterol Lowering and Antioxidative Effect of Pregerminated Brown Rice in Hypercholesterolemic Rats.

Pregerminated brown rice (GBR) is assumed to be more beneficial than polished white rice (WR), with regard to nutrition and cardiovascular health. To support this with scientific evidence, cholesterol-lowering and antioxidative effects of GBR were studied in the present investigation. The most popular rice variety in Bangladesh BIRI-29 was used to prepare GBR and WR. Initially, we analyzed the proximate composition, antioxidative phytochemicals, in vitro 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging ability and anti-hemolytic effects of GBR. To examine the dietary impact and possible benefits of the GBR, experimentally-induced hypercholesterolemic (HC, 1% cholesterol) rats were fed with GBR against WR for 12 wk. At the end, plasma total cholesterol (TC), low- and high-density lipoprotein-cholesterol (LDL-C and HDL-C), triglyceride (TG), fecal TC, and hepatic TC, lipid peroxide (LPO) and proinflammatory TNFα levels were determined. Relative to WR, GBR contained higher amounts of total polyphenols, total flavonoids, ß-carotene and lycopene, and exhibited a stronger in vitro DPPH-free radical scavenging ability and antihemolytic potentials. Levels of plasma TC, LDL-C, TG, and hepatic TC and TG significantly decreased, while plasma HDL-C and fecal TC levels significantly increased in the GBR-fed HC-rats, indicating dietary GBR demonstrates a stronger antilipidemic effect than WR. The hepatic levels of LPO and TNFα also decreased (p<0.05) to a greater extent in GBR-fed HC-rats than those in the WR-fed rats. It is thus concluded that dietary GBR could be a natural treatment of hypercholesterolemia and related cardiovascular risk factors, and a source of antioxidants to reduce hemolysis and related anemia.

Hormonal regulation of cereal endosperm development with a focus on rice (Oryza sativa).

The endosperm of cereal grain forms the staple diet for most of the world's population, and feeds much of their stock. Grain size and quality are determined largely by events taking place during coenocytic nuclear division, endosperm cellularisation and cell differentiation, and the production of storage molecules. Thus, understanding the complex signalling processes occurring at each of these steps is essential for maintaining and improving our food supply. Here, we critically review evidence for the effects of phytohormones on grain size, as well as hormone homeostasis, signalling and crosstalk. We focus on rice endosperm due to the importance of rice as a food crop and a model grass, as well as its relative neglect in recent reviews; however, data from other cereals are also discussed due to strong evidence for conserved signalling networks operating during grain development. Discussion is restricted to auxin, cytokinin, ethylene, abscisic acid and gibberellin. Our review highlights the need for accurate hormone determinations combined with information on gene expression. We present evidence for separate, localised signalling roles for auxin at different stages of grain development and highlight key research questions for other hormones where much less data are available.

Maternal lead exposure decreases the levels of brain development and cognition-related proteins with concomitant upsurges of oxidative stress, inflammatory response and apoptosis in the offspring rats.

The presence of lead (Pb) in fetal brain may affect brain development-related proteins. We studied whether gestational/lactational Pb-exposure affects oxidative stress, proinflammatory response, apoptosis and levels of brain development/cognition-related proteins, including presynaptic synaptosome-associated protein-25 (SNAP-25), postsynaptic density protein-95 (PSD-95), brain-derived neurotropic factor (BDNF), tyrosine receptor-kinase protein B (TrkB) and vesicular acetylcholine transporter (VAChT) in the offspring. Female Wistar rats were randomly divided into control and Pb-exposed mother groups. The Pb-exposed rats received 0.1% (w/v) Pb acetate via drinking water during pregnancy and lactation. Milk and mammary glands were collected from lactating mothers to measure milk/mammary gland levels of lipid peroxide (LPO), as indicator of oxidative stress and proinflammatory TNF-α. Afterwards, the pups were sacrificed to determine brain levels of Pb, LPO, TNF-α, cytochrome C, SNAP-25, PSD-95, BDNF, TrkB and VAChT. The levels of LPO and TNF-α increased in the milk/mammary glands of the Pb-exposed mothers, concurrently with increases in the levels of Pb, LPO, TNF-α and cytochrome C and decreases in the levels of SNAP-25, PSD-95, BDNF, TrkB and VAChT in the brains of their offspring. Our results demonstrate that Pb-exposure during development reduces the brain levels of PSD-95 and SNAP-25 (synaptogenesis-markers), with concomitant upsurges of oxidative stress, TNF-α and apoptosis in the offspring. Furthermore, BDNF-TrkB proteins that comprehend memory-related brain cognitions and/or VAChT that comprises cholinergic-neuromotor activities might be impaired by Pb-exposure. These findings provide evidence of toxic effects of Pb on brain development, at least, partially by decreasing the levels of PSD-95, SNAP-25 and other cognition-related proteins.

Syzygium cumini seed extract protects the liver against lipid peroxidation with concurrent amelioration of hepatic enzymes and lipid profile of alcoholic rats.

The in vitro oxidative stress induced by ethanol/Fenton's reaction in rat liver homogenates decreased significantly in the presence of Syzygium cumini seed extract, suggesting the protective effect of the seed extract against the oxidative stress in liver. To corroborate the in vitro effects by an in vivo experiment, 24 rats were divided into four groups: control, S. cumini seed-extract-administered (SE), 15% ethanol-fed (Alc) and Alc+SE rats. The oral administration of the extract (400 mg/kg BW.day) for 7 weeks significantly decreased the levels of liver LPO in the Alc+SE rats, suggesting that S. cumini seed not only obstructed the in vitro free radical production and subsequent oxidative stress, but also inhibited their in vivo formation. The oral administration of extract also reduced the enzyme activities of serum gammaglutamyl transferase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase and the levels of serum creatinine and blood urea nitrogen, serum/liver triglycerides and total cholesterol of the alcoholic rats. The levels of fecal cholesterol were increased by the extract. Fatty degenerations in liver and kidney were absent with S. cumini seed extract treatment. The results suggest that S. cumini seed may be a potential therapy for alcoholics and related dysfunctions by restraining oxidative stress.