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Plant productivity is determined in large part by the partitioning of assimilates between the sites of production and the sites of utilization. Proton-pumping pyrophosphatases (H⁺-PPases) are shown to participate in many energetic plant processes, including general growth and biomass accumulation, CO₂ fixation, nutrient acquisition, and stress responses. H⁺-PPases have a well-documented role in hydrolyzing pyrophosphate (PPi) and capturing the released energy to pump H⁺ across the tonoplast and endomembranes to create proton motive force (pmf). Recently, an additional role for H⁺-PPases in phloem loading and biomass partitioning was proposed. In companion cells (CCs) of the phloem, H⁺-PPases localize to the plasma membrane rather than endomembranes, and rather than hydrolyzing PPi to create pmf, pmf is utilized to synthesize PPi. Additional PPi in the CCs promotes sucrose oxidation and ATP synthesis, which the plasma membrane P-type ATPase in turn uses to create more pmf for phloem loading of sucrose via sucrose-H⁺ symporters. To test this model, transgenic Arabidopsis (Arabidopsis thaliana) plants were generated with constitutive and CC-specific overexpression of AVP1, encoding type 1 ARABIDOPSIS VACUOLAR PYROPHOSPHATASE1. Plants with both constitutive and CC-specific overexpression accumulated more biomass in shoot and root systems. ¹⁴C-labeling experiments showed enhanced photosynthesis, phloem loading, phloem transport, and delivery to sink organs. The results obtained with constitutive and CC-specific promoters were very similar, such that the growth enhancement mediated by AVP1 overexpression can be attributed to its role in phloem CCs. This supports the model for H⁺-PPases functioning as PPi synthases in the phloem by arguing that the increases in biomass observed with AVP1 overexpression stem from improved phloem loading and transport.

The principal components of plant productivity and nutritional value, from the standpoint of modern agriculture, are the acquisition and partitioning of organic carbon (C) and nitrogen (N) compounds among the various organs of the plant. The flow of essential organic nutrients among the plant organ systems is mediated by its complex vascular system, and is driven by a series of transport steps including export from sites of primary assimilation, transport into and out of the phloem and xylem, and transport into the various import-dependent organs. Manipulating C and N partitioning to enhance yield of harvested organs is evident in the earliest crop domestication events and continues to be a goal for modern plant biology. Research on the biochemistry, molecular and cellular biology, and physiology of C and N partitioning has now matured to an extent that strategic manipulation of these transport systems through biotechnology are being attempted to improve movement from source to sink tissues in general, but also to target partitioning to specific organs. These nascent efforts are demonstrating the potential of applied biomass targeting but are also identifying interactions between essential nutrients that require further basic research. In this review, we summarize the key transport steps involved in C and N partitioning, and discuss various transgenic approaches for directly manipulating key C and N transporters involved. In addition, we propose several experiments that could enhance biomass accumulation in targeted organs while simultaneously testing current partitioning models.

A fundamental factor to improve crop productivity involves the optimization of reduced carbon translocation from source to sink tissues. Here, we present data consistent with the positive effect that the expression of the H -PPase ( ) has on reduced carbon partitioning and yield increases in wheat. Immunohistochemical localization of H -PPases (TaVP) in spring wheat Bobwhite L. revealed the presence of this conserved enzyme in wheat vasculature and sink tissues. Of note, immunogold imaging showed a plasma membrane localization of TaVP in sieve element- companion cell complexes of Bobwhite source leaves. These data together with the distribution patterns of a fluorescent tracer and [U C]-sucrose are consistent with an apoplasmic phloem-loading model in wheat. Interestingly, C-labeling experiments provided evidence for enhanced carbon partitioning between shoots and roots, and between flag leaves and milk stage kernels in AVP1 expressing Bobwhite lines. In keeping, there is a significant yield improvement triggered by the expression of in these lines. Green house and field grown transgenic wheat expressing also produced higher grain yield and number of seeds per plant, and exhibited an increase in root biomass when compared to null segregants. Another agriculturally desirable phenotype showed by AVP1 Bobwhite plants is a robust establishment of seedlings.

The combination of 13C-isotopic labeling and mass spectrometry imaging (MSI) offers an approach to analyze metabolic flux in situ. However, combining isotopic labeling and MSI presents technical challenges ranging from sample preparation, label incorporation, data collection, and analysis. Isotopic labeling and MSI individually create large, complex data sets, and this is compounded when both methods are combined. Therefore, analyzing isotopically labeled MSI data requires streamlined procedures to support biologically meaningful interpretations. Using currently available software and techniques, here we describe a workflow to analyze 13C-labeled isotopologues of the membrane lipid and storage oil lipid intermediate―phosphatidylcholine (PC). Our results with embryos of the oilseed crops, Camelina sativa and Thlaspi arvense (pennycress), demonstrated greater 13C-isotopic labeling in the cotyledons of developing embryos compared with the embryonic axis. Greater isotopic enrichment in PC molecular species with more saturated and longer chain fatty acids suggest different flux patterns related to fatty acid desaturation and elongation pathways. The ability to evaluate MSI data of isotopically labeled plant embryos will facilitate the potential to investigate spatial aspects of metabolic flux in situ.

Phloem loading is a critical process in plant physiology. The potential of regulating the translocation of photoassimilates from source to sink tissues represents an opportunity to increase crop yield. Pyrophosphate homeostasis is crucial for normal phloem function in apoplasmic loaders. The involvement of Arabidopsis (Arabidopsis thaliana) type I proton-pumping pyrophosphatase (AVP1) in phloem loading was analyzed at genetic, histochemical, and physiological levels. A transcriptionalAVP1promoter:: GUS fusion revealed phloem activity in source leaves. UbiquitousAVP1overexpression (35S::AVP1cassette) enhanced shoot biomass, photoassimilate production and transport, rhizosphere acidification, and expression of sugar-induced root ion transporter genes (POTASSIUM TRANSPORTER2[KUP2],NITRATE TRANSPORTER2.1[NRT2.1],NRT2.4, andPHOSPHATE TRANSPORTER1.4[PHT1.4]). Phloem-specificAVP1overexpression (Commelina Yellow Mottle Virus promoter[pCOYMV]::AVP1) elicited similar phenotypes. By contrast, phloem-specificAVP1knockdown (pCoYMV:: RNAiAVP1)resulted in stunted seedlings in sucrose-deprived medium. We also present a promoter mutantavp1-2(SALK046492) with a 70% reduction of expression that did not show severe growth impairment. Interestingly, AVP1 protein in this mutant is prominent in the phloem.Moreover, expression of anEscherichia colisoluble pyrophosphatase in the phloem (pCoYMV::pyrophosphatase) ofavp1-2plants resulted in severe dwarf phenotype and abnormal leaf morphology. We conclude that the Proton-Pumping Pyrophosphatase AVP1 localized at the plasma membrane of the sieve element-companion cell complexes functions as a synthase, and that this activity is critical for the maintenance of pyrophosphate homeostasis required for phloem function.

The brachial plexus block is one of the peripheral blocks, beneath which the majority of upper limb surgical procedures are carried out. During upper limb surgery, a supraclavicular nerve block is an excellent substitute for general anesthesia. This is a clinical comparative study of dexmedetomidine, dexamethasone, and clonidine as adjuvants to local anesthetics in supraclavicular brachial plexus block. Ninety patients with American Society of Anesthesiologists (ASA) grades I and II scheduled for upper limb surgeries were randomly divided into three groups. Group RDEX (ropivacaine + dexmedetomidine; n = 30) received 20 ml of 0.5% inj. ropivacaine with 10 ml of 2% lignocaine and adrenaline with inj. dexmedetomidine 1 µg /kg (32 ml solution). Group RC (ropivacaine + clonidine; n = 30) received 20 ml of 0.5% inj. ropivacaine with 10 ml of 2% lignocaine and adrenaline with inj. clonidine 1 µg /kg (32 ml solution). Group RD (ropivacaine + dexamethasone; n = 30) received 20 ml of 0.5% inj. ropivacaine with 10 ml of 2% lignocaine and adrenaline with inj. dexamethasone 2 ml (8 mg) (32 ml solution). The onset of sensory and motor block was a statistically significant difference among the three groups (p < 0.001), showing that Group RDEX has the faster onset, followed by Group RC and Group RD as the slowest. There was a statistically significant difference in the mean duration of sensory and motor block among the three groups (p < 0.001), showing that Group RDEX has the longest average duration, followed by Group RC, while Group RD has the shortest. The comparison of the mean duration of analgesia shows a statistically highly significant difference among the three groups (p < 0.001). Dexmedetomidine (RDEX) has the longest duration of analgesia, followed by Group RC and then Group RD. The hemodynamic profile was comparable among the three groups. Sedation was observed in Groups RDEX and RC. Overall, no complications were found in Group RD. Dexmedetomidine, when added to 0.5% ropivacaine for supraclavicular brachial plexus blocks, decreases the time of onset of sensory and motor blockade and prolongs the duration of the block and the duration of analgesia as compared to clonidine and dexamethasone with 0.5% ropivacaine, making it a better adjuvant to ropivacaine for upper limb surgeries.

The combination of C-isotopic labeling and mass spectrometry imaging (MSI) offers an approach to analyze metabolic flux in situ. However, combining isotopic labeling and MSI presents technical challenges ranging from sample preparation, label incorporation, data collection, and analysis. Isotopic labeling and MSI individually create large, complex data sets, and this is compounded when both methods are combined. Therefore, analyzing isotopically labeled MSI data requires streamlined procedures to support biologically meaningful interpretations. Using currently available software and techniques, here we describe a workflow to analyze C-labeled isotopologues of the membrane lipid and storage oil lipid intermediate-phosphatidylcholine (PC). Our results with embryos of the oilseed crops, and (pennycress), demonstrated greater C-isotopic labeling in the cotyledons of developing embryos compared with the embryonic axis. Greater isotopic enrichment in PC molecular species with more saturated and longer chain fatty acids suggest different flux patterns related to fatty acid desaturation and elongation pathways. The ability to evaluate MSI data of isotopically labeled plant embryos will facilitate the potential to investigate spatial aspects of metabolic flux in situ.

The combination of 13C-isotopic labeling and mass spectrometry imaging (MSI) offers an approach to analyze metabolic flux in situ. However, combining isotopic labeling and MSI presents technical challenges ranging from sample preparation, label incorporation, and data collection and analysis. Isotopic labeling and MSI each create large, complex data sets, and this is compounded when both methods are combined. Therefore, analyzing isotopically labeled MS imaging data requires streamlined procedures to support biologically meaningful interpretations. Using currently available software and techniques, here we describe a workflow to analyze 13C-labeled isotopomers of the membrane lipid and storage oil lipid intermediate-- phosphatidylcholine (PC). Our results with embryos of the oilseed crops, Camelina sativa and Thlaspi arvense (Pennycress), demonstrated greater 13C-isotopic labeling in the cotyledons of developing embryos compared with the embryonic axis. Greater isotopic enrichment in PC molecular species with more saturated and longer chain fatty acids suggest different flux patterns related to fatty acid desaturation and elongation pathways. The ability to evaluate MSI data of isotopically labeled plant embryos will facilitate the potential to investigate spatial aspects of metabolic flux in situ.

The combination of 13C-isotopic labeling and mass spectrometry imaging (MSI) offers an approach to analyze metabolic flux in situ. However, combining isotopic labeling and MSI presents technical challenges ranging from sample preparation, label incorporation, data collection, and analysis. Isotopic labeling and MSI individually create large, complex data sets, and this is compounded when both methods are combined. Therefore, analyzing isotopically labeled MSI data requires streamlined procedures to support biologically meaningful interpretations. Using currently available software and techniques, here we describe a workflow to analyze 13C-labeled isotopologues of the membrane lipid and storage oil lipid intermediate-phosphatidylcholine (PC). Our results with embryos of the oilseed crops, Camelina sativa and Thlaspi arvense (pennycress), demonstrated greater 13C-isotopic labeling in the cotyledons of developing embryos compared with the embryonic axis. Greater isotopic enrichment in PC molecular species with more saturated and longer chain fatty acids suggest different flux patterns related to fatty acid desaturation and elongation pathways. The ability to evaluate MSI data of isotopically labeled plant embryos will facilitate the potential to investigate spatial aspects of metabolic flux in situ.

This proposed work is presenting the approximation of higher-order (HO) underwater robotic vehicle (URV) controller with the help of multi-point matching technique by incorporating greywolf optimization algorithm (GWOA). The performance of URV system is affected by external and internal dynamics. The proper momentum of URV system is achieved by designing a controller. The URV can be effectively operated by control action of controller. The URV controller is approximated to comparatively lower-order (LO) to propose an efficient, effective and economical controller for HOURV system. The approximation is accomplished with the help of expansion parameters of HOURV controller and its desired LOURV controller. The errors between these expansion parameters of HOURV controller and its desired LOURV controller are minimized using multi-point matching. The multi-point matching is depicted in the form of objective function (OF). The constructed OF is minimized by exploiting GWOA by fulfilling the steady-state matching condition and Hurwitz stability criterion, as constraints. The effectiveness of proposed approach of multi-point matching is verified by comparing the proposed LOURV model with LOURV models obtained with the help of other approximation approaches. The applicability of proposed LOURV controller is evaluated and validated by analyzing responses and tabulated data obtained in the results. Additionally, the statistical data of performance error values (PEVs) are provided in tabulated form along with its bar plot.