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W e provide a branch-and-price algorithm for the bin packing problem with conflicts, a variant of the classical bin packing problem that has major applications in scheduling and resource allocation. The proposed algorithm benefits from a number of special features that greatly contribute to its efficiency. First, we use a branching rule that matches the conflicting constraints, preserving the structure of the subproblems after branching. Second, maximal clique valid inequalities are generated based on the conflicting constraints and are added to the subproblems. The algorithm is tested on a standard set of problems and is compared to a recently proposed approach. Numerical results indicate its efficiency and stability.

Edited by Jeffrey E. Pessin Patients with fatty liver diseases present altered mitochondrial morphology and impaired metabolic function. Mitochondrial dynamics and related cell function require the uncleaved form of the dynamin-like GTPase OPA1. Stabilization of OPA1 might then confer a protective mechanism against stress-induced tissue damages. To study the putative role of hepatic mitochondrial morphology in a sick liver, we expressed a cleavage-resistant long form of OPA1 (L-OPA1⌬) in the liver of a mouse model with mitochondrial liver dysfunction (i.e. the hepatocyte-specific prohibitin-2 knockout (Hep-Phb2 ؊/؊) mice). Liver prohibitin-2 deficiency caused excessive proteolytic cleav-ageofL-OPA1,mitochondrialfragmentation,andincreasedapoptosis. These molecular alterations were associated with lipid accumulation, abolished gluconeogenesis, and extensive liver damage. Such liver dysfunction was associated with severe hypoglycemia. In prohibitin-2 knockout mice, expression of L-OPA1⌬ by in vivo adenovirus delivery restored the morphology but not the function of mitochondria in hepatocytes. In prohibitin-competent mice, elongation of liver mitochondria by expression of L-OPA1⌬ resulted in excessive glucose production associated with increased mitochondrial respiration. In conclusion, mitochondrial dynamics participates in the control of hepatic glucose production. This work was supported by Swiss National Science Foundation Sinergia Grants CRSII3_147637 (to P. M. and J.-C. M.) and 310030_172862 (to M. F.) and by a fellowship from the Fundación Alfonso Martín Escudero (to C. J. S). The authors declare that they have no conflicts of interest with the contents of this article. This article was selected as one of our Editors' Picks. This article contains Tables S1 and S2 and Figs. S1-S8.

BackgroundWater deficit severely reduces apple growth and production, is detrimental to fruit quality and size. This problem is exacerbated as global warming is implicated in producing more severe drought stress. Thus water-efficiency has becomes the major target for apple breeding. A desired apple tree can absorb and transport water efficiently, which not only confers improved drought tolerance, but also guarantees fruit size for higher income returns. Aquaporins, as water channels, control water transportation across membranes and can regulate water flow by changing their amount and activity. The exploration of molecular mechanism of water efficiency and the gene wealth will pave a way for molecular breeding of drought tolerant apple tree.ResultsIn the current study, we screened out a drought inducible aquaporin gene MdPIP1;3, which specifically enhanced its expression during fruit expansion in ‘Fuji’ apple (Malus domestica Borkh. cv. Red Fuji). It localized on plasma membranes and belonged to PIP1 subfamily. The tolerance to drought stress enhanced in transgenic tomato plants ectopically expressing MdPIP1;3, showing that the rate of losing water in isolated transgenic leaves was slower than wild type, and stomata of transgenic plants closed sensitively to respond to drought compared with wild type. Besides, length and diameter of transgenic tomato fruits increased faster than wild type, and in final, fruit sizes and fresh weights of transgenic tomatoes were bigger than wild type. Specially, in cell levels, fruit cell size from transgenic tomatoes was larger than wild type, showing that cell number per mm2 in transgenic fruits was less than wild type.ConclusionsAltogether, ectopically expressing MdPIP1;3 enhanced drought tolerance of transgenic tomatoes partially via reduced water loss controlled by stomata closure in leaves. In addition, the transgenic tomato fruits are larger and heavier with larger cells via more efficient water transportation across membranes. Our research will contribute to apple production, by engineering apples with big fruits via efficient water transportation when well watered and enhanced drought tolerance in transgenic apples under water deficit.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1212-2) contains supplementary material, which is available to authorized users.

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