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Summary The plant hormone auxin and its directional intercellular transport play a major role in diverse aspects of plant growth and development. The establishment of auxin gradients requires the asymmetric distribution of members of the auxin efflux carrier PIN‐FORMED (PIN) protein family to the plasma membrane. An endocytic pathway regulates the recycling of PIN proteins between the plasma membrane and endosomes, providing a mechanism for dynamic localisation. N‐Ethylmaleimide‐sensitive factor adaptor protein receptors (SNAP receptors, SNAREs) mediate fusion between vesicles and target membranes and are classed as Q‐ or R‐SNAREs based on their sequence. We analysed gain‐ and loss‐of‐function mutants, dominant‐negative transgenics and localisation of the Arabidopsis R‐SNARE VAMP714 protein to understand its function.We demonstrate that VAMP714 is essential for the insertion of PINs into the plasma membrane, for polar auxin transport, root gravitropism and morphogenesis. VAMP714 gene expression is upregulated by auxin, and the VAMP714 protein co‐localises with endoplasmic reticulum and Golgi vesicles and with PIN proteins at the plasma membrane.It is proposed that VAMP714 mediates the delivery of PIN‐carrying vesicles to the plasma membrane, and that this forms part of a positive regulatory loop in which auxin activates a VAMP714‐dependent PIN/auxin transport system to control development.

SummaryThe plant hormone auxin and its directional intercellular transport plays a major role in diverse aspects of plant growth and development. The establishment of auxin gradients in plants requires asymmetric distribution of members of the auxin efflux carrier PIN-FORMED (PIN) protein family to the plasma membrane. An endocytic pathway regulates the recycling of PIN proteins between the plasma membrane and endosomes, providing a mechanism for dynamic localization.N-ethylmaleimide-sensitive factor adaptor protein receptors (SNAP receptors, SNAREs) mediate fusion between vesicles and target membranes and are classed as Q- or R-SNAREs based on their sequence. We analysed gain- and loss-of-function mutants, dominant negative transgenics and protein localization of the Arabidopsis R-SNARE VAMP714 to understand its function.We demonstrate that VAMP714 is essential for the insertion of PINs into the plasmamembrane, for polar auxin transport, and for root gravitropism and morphogenesis.VAMP714gene expression is upregulated by auxin, and the VAMP714 protein co-localizes with ER and Golgi vesicles and with PIN proteins at the plasma membrane.It is proposed that VAMP714 mediates the delivery of PIN-carrying vesicles to the plasma membrane, and that this forms part of a positive regulatory loop in which auxin activates a VAMP714-dependent PIN/auxin transport system to control development.

The combined effect of gallic acid (3,4,5-trihydroxy benzoic acid; GA; 50 mg kg(-1) i.p.) and propolis (200 mg kg(-1) p.o.) was evaluated against beryllium-induced biochemical and morphological alterations in the liver and kidney. Female albino rats were exposed to beryllium nitrate (1 mg kg(-1) i.p.) daily for 28 days followed by treatment with the above mentioned therapeutic agents either individually or in combination for five consecutive days. Exposure to beryllium increased its concentration in the serum, liver and kidney and caused significant alterations in cytochrome P450 enzymes, microsomal lipid peroxidation and protein contents. Beryllium administration significantly altered the aspartate aminotransaminase, alanine aminotransaminase, lactate dehydrogenase, γ-grutamy1 transpeptidase, bilirubin, creatinine and urea in serum, and the activity of acid phosphatase, alkaline phosphatase, adenosine triphosphatase, glucose-6-phophatase and succinic dehydrogenase, triglycerides, cholesterol, protein contents, glycogen contents, lipid peroxidation and glutathione level in the liver and kidney. Beryllium exposure induced severe alterations in hepatorenal morphology, revealing its toxic consequences at a cellular level. Individual administration of GA and propolis reduced the effects on the studied parameters to a degree. Interestingly, GA in conjunction with propolis reversed the alterations in all of the variables examined, highlighting the beneficial effects of combined therapy over monotherapy in the alleviation of beryllium-induced systemic toxicity.