All-organic transparent plant e-skin for noninvasive phenotyping

Real-time in situ monitoring of plant physiology is essential for establishing a phenotyping platform for precision agriculture. A key enabler for this monitoring is a device that can be noninvasively attached to plants and transduce their physiological status into digital data. Here, we report an all-organic transparent plant e-skin by micropatterning poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) on polydimethylsiloxane (PDMS) substrate. This plant e-skin is optically and mechanically invisible to plants with no observable adverse effects to plant health. We demonstrate the capabilities of our plant e-skins as strain and temperature sensors, with the application to Brassica rapa leaves for collecting corresponding parameters under normal and abiotic stress conditions. Strains imposed on the leaf surface during growth as well as diurnal fluctuation of surface temperature were captured. We further present a digital-twin interface to visualize real-time plant surface environment, providing an intuitive and vivid platform for plant phenotyping.

Regulation of primary seed dormancy by MAJOR LATEX PROTEIN-LIKE PROTEIN329 in Arabidopsis is dependent on DNA-BINDING ONE ZINC FINGER6

Seeds exhibit primary dormancy to prevent germination under unfavourable conditions. Previous studies have shown that the gibberellin signalling intermediate RGA-LIKE2 (RGL2) forms a transcription factor complex with DNA-BINDING ONE ZINC FINGER6 (DOF6) in regulating seed dormancy in Arabidopsis. Using an RNA-sequencing approach, we identified MAJOR LATEX PROTEIN-LIKE PROTEIN329 (MLP329) as a downstream target of DOF6. MLP329 was found to be a positive regulator of primary seed dormancy, because freshly harvested unstratified mlp329 mutant seeds showed early germination, while unstratified transgenic seeds overexpressing MLP329 showed poor germination. MLP329 expression level was reduced in wild-type seeds upon dry storage and cold stratification. MLP329 expression level was enhanced by DOF6; however, DOF6-dependent MLP329 expression was suppressed in the presence of RGL2. MLP329 expression was enhanced in seeds treated with ABA and auxin IAA. Moreover, the mlp329 mutant seeds exhibited enhanced expression of the GA biosynthetic gene GA1 and suppression of the ABA biosynthetic gene ZEP compared to the overexpression lines. The observed suppression of DOF6-dependent MLP329 expression by RGL2 reveals a possible negative feedback mechanism to modulate seed dormancy. MLP329 also probably enhances the endogenous ABA/GA ratio to positively regulate primary seed dormancy.

Ethylene-Mediated Modulation of Bud Phenology, Cold Hardiness, and Hormone Biosynthesis in Peach (Prunus persica)

Spring frosts exacerbated by global climate change have become a constant threat to temperate fruit production. Delaying the bloom date by plant growth regulators (PGRs) has been proposed as a practical frost avoidance strategy. Ethephon is an ethylene-releasing PGR found to delay bloom in several fruit species, yet its use is often coupled with harmful effects, limiting its applicability in commercial tree fruit production. Little information is available regarding the mechanisms by which ethephon influences blooming and bud dormancy. This study investigated the effects of fall-applied ethephon on bud phenology, cold hardiness, and hormonal balance throughout the bud dormancy cycle in peach. Our findings concluded that ethephon could alter several significant aspects of peach bud physiology, including accelerated leaf fall, extended chilling accumulation period, increased heat requirements, improved cold hardiness, and delayed bloom date. Ethephon effects on these traits were primarily dependent on its concentration and application timing, with a high concentration (500 ppm) and an early application timing (10% leaf fall) being the most effective. Endogenous ethylene levels were induced significantly in the buds when ethephon was applied at 10% versus 90% leaf fall, indicating that leaves are essential for ethephon uptake. The hormonal analysis of buds at regular intervals of chilling hours (CH) and growing degree hours (GDH) also indicated that ethephon might exert its effects through an abscisic acid (ABA)-independent way in dormant buds. Instead, our data signifies the role of jasmonic acid (JA) in mediating budburst and bloom in peach, which also appears to be influenced by ethephon treatment. Overall, this research presents a new perspective in interpreting horticultural traits in the light of biochemical and molecular data and sheds light on the potential role of JA in bud dormancy, which deserves further attention in future studies that aim at mitigating spring frosts.

An LRR-only protein regulates abscisic acid-mediated abiotic stress responses during Arabidopsis seed germination

LRRop-1, induced by DOF6 transcription factor, negatively regulates abiotic stress responses during Arabidopsis seed germination. The lrrop-1 mutant has reduced ABA signaling, which is part of the underlying stress-remediation mechanism. The large family of leucine-rich repeat (LRR) proteins plays a role in plant immune responses. Most LRR proteins have multiple functional domains, but a subfamily is known to possess only the LRR domain. The roles of these LRR-only proteins in Arabidopsis remain largely uncharacterized. In the present study, we have identified 44 LRR-only proteins in Arabidopsis and phylogenetically classified them into nine sub-groups. We characterized the function of LRRop-1, belonging to sub-group V. LRRop-1 encodes a predominantly ER-localized LRR domain-containing protein that is highly expressed in seeds and rosette leaves. Promoter motif analysis revealed an enrichment in binding sites for several GA-responsive and stress-responsive transcription factors. The lrrop-1 mutant seeds showed enhanced seed germination on medium containing abscisic acid (ABA), paclobutrazol and NaCl compared to the wild type (WT), demonstrating higher abiotic stress tolerance. Also, the lrrop-1 mutant seeds have lower levels of endogenous ABA, but higher levels of gibberellic acid (GA) and jasmonic acid-Ile (JA-Ile) compared to the WT. Furthermore, lrrop-1 mutant seeds imbibed with ABA exhibited reduced expression of ABA-responsive genes compared to similarly treated WT seeds, suggesting suppressed ABA signaling events in the mutant. Furthermore, chromatin immunoprecipitation (ChIP) data showed that DNA BINDING1 ZINC FINGER6 (DOF6), a negative regulator of seed germination, could directly bind to the LRRop-1 promoter and up-regulate its expression. Thus, our results show that LRRop-1 regulates ABA-mediated abiotic stress responses during Arabidopsis seed germination.

Role of W-site substitution on mechanical and electronic properties of cubic tungsten carbide

In order to understand the role of W-site substitution on properties of cubic tungsten carbide ([Formula: see text]-WC), we have investigated the structural, mechanical, and electronic properties of WXC₂ (X  =  Si, Sc, Ti, V, Cr, Ge, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Sn, Hf, Ta, Re, Os, Ir, Pt, Th, U) using first principles calculations based on density functional theory, within generalized gradient approximation. The structural optimization has carried out for all these compounds using force as well as stress minimization. The optimized structural parameters for experimentally known compounds are in good agreement with the available x-ray diffraction measurements and structural parameters for nineteen WXC₂ compounds are newly predicted. The W-site substitution of the above-listed elements into [Formula: see text]-WC reduces the symmetry of the primitive lattice to tetragonal structure. The heat of formation ([Formula: see text]) and the mechanical stability studies are carried out to investigate the stability of these systems. The single-crystal elastic constants c _ij , elastic moduli of the polycrystalline aggregates, anisotropy in elastic constants and related properties of the WXC₂ materials have calculated and discussed in detail. The hardness of the above materials is predicted using two different criteria, based on the softest elastic mode as well as the Pugh's modulus ratio. There is a correlation in the hardness predicted from these two approaches except in the case of [Formula: see text]-WC. The chemical bonding interaction between the constituents is analysed using the density of states, crystal orbital Hamiltonian population, and charge density for selected systems. All these compounds are predicted to be metal and our calculations suggest that W-site substitutions do not improve the hardness of [Formula: see text]-WC. However, from the heat of formation studies, we have identified five new stable compounds such as CrWC₂, NbWC₂, ScWC₂, YWC₂, and UWC₂ with reasonably good hardness and those need experimental verifications.

Potential hydrogen storage materials from metal decorated 2D-C2N: an ab initio study

Two dimensional nitrogenated holey graphene (2D-C₂N) is often considered as an ideal material for hydrogen storage applications owing to its lower mass density and high surface-to-volume ratio. As the interaction between H₂ and pristine 2D-C₂N is very weak with an adsorption energy of only 0.10 eV per H₂, it is important to improve it through appropriate materials design. Using density functional theory calculations, we investigated the hydrogen storage properties of metal (M = Mg, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, and Zn) decorated 2D-C₂N. From this study, we found that M binding energy on 2D-C₂N is greater than the cohesive energy of the respective bulk metals, indicating that the metal is strongly bonded with the 2D-C₂N, which rules out the metal clustering issue. In particular, 2D-C₂N with Mg decoration leads to 6.79 wt% hydrogen storage capacity with a desirable adsorption energy which is above the Department of Energy's target. The electronic structure analyses show that the Mg decoration leads to a semiconductor-to-metallic transition in 2D-C₂N. Our chemical bonding analyses through partial density of states, charge density, electron localization function, charge transfer, and Bader effective charge confirm the presence of an iono-covalent character for Mg decorated 2D-C₂N. This indicates that the H₂ molecules are adsorbed by a polarization mechanism. Overall, our results suggest that Mg decorated 2D-C₂N is a promising candidate for potential hydrogen storage applications.

Cluster containment strategy: addressing Zika virus outbreak in Rajasthan, India

India is at risk of Zika virus transmission due to high prevalence of its vector Aedes aegypti. Rajasthan, a state in the north-west region of India, has also high prevalence of Aedes mosquito. First laboratory confirmed case of Zika virus disease in Rajasthan was reported on 21 September 2018 in Jaipur. The Government of Rajasthan quickly implemented a containment strategy to contain the outbreak and prevent further spread of this disease. Strategy included active human and mosquito surveillance, laboratory testing and sequencing of the virus, integrated vector control measures, intersectoral coordination, risk communication and social mobilisation, all in a predefined geographic area around the epicentre. Timely action with appropriate coordination at all levels with multiple stakeholders contained the outbreak successfully. In all, 159 confirmed cases were reported from in and around the 3 km containment zone in Shastri Nagar area of Jaipur City and routine surveillance. Following this, a specially developed laboratory-based surveillance strategy was put in place to ensure that the disease does not spread beyond the containment zone. No fresh case was reported subsequently within or beyond the containment zone.

Metamagnetism stabilized giant magnetoelectric coupling in ferroelectric xBaTiO3-(1 - x)BiCoO3 solid solution

In order to establish the correlation between the magnetoelectric coupling and magnetic instability, we have studied the structural, magnetic, and ferroelectric properties of BaTiO₃ modified BiCoO₃i.e. xBaTiO₃-(1 - x)BiCoO₃ as a function of BaTiO₃ concentration (x) and volume from a series of general-gradient-corrected (GGA), GGA plus onsite Coulomb repulsion (U), full potential, spin-density-functional band-structure calculations within the framework of density functional theory along with synchrotron X-ray diffraction and magnetic measurement studies. G-type antiferromagnetic ordering was found to be energetically favorable among all the considered magnetic configurations for x < 0.45 and higher concentrations stabilize with nonmagnetic (NM) states. We observe metamagnetic spin state transitions associated with paraelectric to ferroelectric transitions as a function of volume and x using synchrotron diffraction and computational studies, indicating a strong magnetoelectric coupling. Specifically for x = 0.33 composition, a pressure induced high spin (HS) to low spin (LS) transition occurs when the volume is compressed below 2.5%. Our orbital-projected density of states show a HS state for Co³⁺ in the ferroelectric ground state for x < 0.45 and the corresponding paraelectric phase is stable in the NM state due to the stabilization of LS state as evident from our fixed-spin-moment calculations and magnetic measurements. The nature of chemical bonding has been studied using partial density of states, electron localization function, and Born effective charge analysis. High values of spontaneous ferroelectric polarizations are predicted for lower x values which inversely vary with x because of the reduction of tetragonality (c/a) with increase in x which indicates the presence of both spin-lattice and ferroelectricity-lattice coupling. Our partial polarization analysis shows that not only the lone pair at Bi sites but also the d⁰-ness of Ti⁴⁺ ions contribute to the net polarization. Moreover, we find that the HS-LS transition point and magnetoelectric coupling strength can be varied by x.

A Novel RGL2-DOF6 Complex Contributes to Primary Seed Dormancy in Arabidopsis thaliana by Regulating a GATA Transcription Factor

The DELLA protein RGA-LIKE2 (RGL2) is a key transcriptional repressor of gibberellic acid (GA) signaling that regulates seed germination. We identified GATA12, a gene encoding a GATA-type zinc finger transcription factor, as one of the downstream targets of RGL2 in Arabidopsis thaliana. Our data show that freshly harvested (unstratified) seeds of GATA12 antisense suppression lines have reduced dormancy compared with the wild-type, while ectopic expression lines show enhanced seed dormancy. We show that GATA12 expression is negatively regulated by GA, and its transcript levels decline dramatically under dormancy-breaking conditions such as dry storage and cold stratification of seeds. GATA12 promoter has several GAMYB- and DOF-associated motifs that are known to be GA- and RGL2-responsive, respectively. Chromatin immunoprecipitation assay showed that a protein complex containing RGL2 can bind to GATA12 promoter and thereby regulate its expression. RGL2 lacks a DNA binding domain and requires a transcription factor to induce GATA12 expression. Our data show that this RGL2-containing protein complex includes DNA BINDING1 ZINC FINGER6 (DOF6), which is a known negative regulator of germination in freshly harvested seeds. We further show that this novel RGL2-DOF6 complex is required for activating GATA12 expression, thus revealing a molecular mechanism to enforce primary seed dormancy.

Plant hormone-mediated regulation of stress responses

BACKGROUND

Being sessile organisms, plants are often exposed to a wide array of abiotic and biotic stresses. Abiotic stress conditions include drought, heat, cold and salinity, whereas biotic stress arises mainly from bacteria, fungi, viruses, nematodes and insects. To adapt to such adverse situations, plants have evolved well-developed mechanisms that help to perceive the stress signal and enable optimal growth response. Phytohormones play critical roles in helping the plants to adapt to adverse environmental conditions. The elaborate hormone signaling networks and their ability to crosstalk make them ideal candidates for mediating defense responses.

RESULTS

Recent research findings have helped to clarify the elaborate signaling networks and the sophisticated crosstalk occurring among the different hormone signaling pathways. In this review, we summarize the roles of the major plant hormones in regulating abiotic and biotic stress responses with special focus on the significance of crosstalk between different hormones in generating a sophisticated and efficient stress response. We divided the discussion into the roles of ABA, salicylic acid, jasmonates and ethylene separately at the start of the review. Subsequently, we have discussed the crosstalk among them, followed by crosstalk with growth promoting hormones (gibberellins, auxins and cytokinins). These have been illustrated with examples drawn from selected abiotic and biotic stress responses. The discussion on seed dormancy and germination serves to illustrate the fine balance that can be enforced by the two key hormones ABA and GA in regulating plant responses to environmental signals.

CONCLUSIONS

The intricate web of crosstalk among the often redundant multitudes of signaling intermediates is just beginning to be understood. Future research employing genome-scale systems biology approaches to solve problems of such magnitude will undoubtedly lead to a better understanding of plant development. Therefore, discovering additional crosstalk mechanisms among various hormones in coordinating growth under stress will be an important theme in the field of abiotic stress research. Such efforts will help to reveal important points of genetic control that can be useful to engineer stress tolerant crops.

Theoretical and experimental investigation on structural, electronic and magnetic properties of layered Mn5O8

Using density functional theory calculations and NPD measurements, we have identified that Mn₅O₈is a strongly correlated mixed valent antiferromagnetic metal.

A stable JAZ protein from peach mediates the transition from outcrossing to self-pollination

BACKGROUND

Variations in floral display represent one of the core features associated with the transition from allogamy to autogamy in angiosperms. The promotion of autogamy under stress conditions suggests the potential involvement of a signaling pathway with a dual role in both flower development and stress response. The jasmonic acid (JA) pathway is a plausible candidate to play such a role because of its involvement in many plant responses to environmental and developmental cues. In the present study, we used peach (Prunus persica L.) varieties with showy and non-showy flowers to investigate the role of JA (and JA signaling suppressors) in floral display.

RESULTS

Our results show that PpJAZ1, a component of the JA signaling pathway in peach, regulates petal expansion during anthesis and promotes self-pollination. PpJAZ1 transcript levels were higher in petals of the non-showy flowers than those of showy flowers at anthesis. Moreover, the ectopic expression of PpJAZ1 in tobacco (Nicotiana tabacum L.) converted the showy, chasmogamous tobacco flowers into non-showy, cleistogamous flowers. Stability of PpJAZ1 was confirmed in vivo using PpJAZ1-GFP chimeric protein. PpJAZ1 inhibited JA-dependent processes in roots and leaves of transgenic plants, including induction of JA-response genes to mechanical wounding. However, the inhibitory effect of PpJAZ1 on JA-dependent fertility functions was weaker, indicating that PpJAZ1 regulates the spatial localization of JA signaling in different plant organs. Indeed, JA-related genes showed differential expression patterns in leaves and flowers of transgenic plants.

CONCLUSIONS

Our results reveal that under stress conditions – for example, herbivore attacks – stable JAZ proteins such as PpJAZ1 may alter JA signaling in different plant organs, resulting in autogamy as a reproductive assurance mechanism. This represents an additional mechanism by which plant hormone signaling can modulate a vital developmental process in response to stress.

Structural and electronic properties of transparent conducting delafossite: a comparison between the AgBO2 and CuBO2 families (B = Al, Ga, In and Sc, Y)

The Ag-based delafossite transparent conducting oxides are potential p-type materials for transparent electronics. However, they have attracted less attention due to their difficult synthetic chemistry and relatively low conductivity.

Observation of direct magneto-dielectric behaviour in Lu3Fe5O12−δ above room-temperature

Oxygen vacancy created an intrinsic magneto-dielectric effect in Lu₃Fe₅O₁₂.

The extent of inflammation is a predictor for pouch-related complications in ileal pouches in patients with ulcerative or indeterminate colitis

AIM

Limited data are available on the relationship between the histological features of the resected specimens in patients with ulcerative colitis (UC) or indeterminate colitis (IC) and the outcome of restorative proctocolectomy. The aim of our study was to determine if the histological features of the resected specimen in patients with UC and IC can predict ileal-pouch-related outcome.

METHOD

A review of all patients who had a restorative proctocolectomy created following completion proctectomy or proctocolectomy for UC and IC was performed.

RESULTS

Between 1992 and 2011, 142 patients (132 with UC and 10 with IC) were reviewed. After a median follow-up of 36 (3-149) months, 51 (35.9%) developed a pouch-related complication. Forty-two (29.7%) developed pouchitis while three (2.1%) developed a pouch-cutaneous fistula. Four (2.8%) had pouch failure, while stricture of the anastomosis was seen in three (2.1%) patients. The presence of extension of the inflammation into the muscularis propria of the resected specimen was associated with an increased risk of pouch-related complications (P = 0.01). The presence of submucosal oedema was also a significant risk factor (P = 0.03).

CONCLUSION

The extension of inflammation into the muscularis propria appears to predict pouch-related complications following restorative proctocolectomy for UC or IC.

Definitive surgical closure of enterocutaneous fistula: outcome and factors predictive of increased postoperative morbidity

AIM

Enterocutaneous fistula (ECF) presents a complex management problem with significant mortality and morbidity. The aim of this study was to assess the outcome of patients undergoing surgical cure for ECF and to predict factors that might relate to increased postoperative morbidity.

METHOD

Medical records of all patients who underwent definitive surgery for cure of an ECF within our colorectal surgery unit between 2000 and 2010 were reviewed.

RESULTS

Forty-one patients (18 male) were identified, in whom 44 definitive procedures were performed. The median age was 54 (17-81) years. The median postoperative length of stay in hospital was 14 (2-213) days. Half (50%) of the ECFs occurred as a postoperative complication followed by spontaneous fistulation in Crohn's disease (36%). The interval to definitive surgery was influenced by the aetiology of the fistula. The median time to surgery after formation of postoperative fistula was 240 days (7.9 months). There was no 30-day postoperative mortality. There were two (4.5%) recurrences at 3 months. Thirty-eight (86%) patients suffered postoperative morbidity as defined by the Clavien-Dindo classification. High-grade morbidity occurred in 32% of patients. On univariate analysis, factors identified as being significantly associated with high-grade morbidity included a fistula output of > 500 ml/day (P = 0.004) in patients with postoperative ECF, malnutrition at presentation (P = 0.04) and a serum albumin value of < 30 g/l (P = 0.02) in patients with spontaneous ECF due to Crohn's disease.

CONCLUSION

The majority of persistent complex ECFs can be cured surgically with low mortality and recurrence in a multidisciplinary setting. Postoperative morbidity, however, remains a significant burden.

Characterization of gibberellin-signalling elements during plum fruit ontogeny defines the essentiality of gibberellin in fruit development

Fruit growth is a coordinated, complex interaction of cell division, differentiation and expansion. Gibberellin (GA) involvement in the reproductive events is an important aspect of GA effects. Perennial fruit-trees such as plum (Prunus salicina L.) have distinct features that are economically important and provide opportunities to dissect specific GA mechanisms. Currently, very little is known on the molecular mechanism(s) mediating GA effects on fruit development. Determination of bioactive GA content during plum fruit ontogeny revealed that GA1 and GA4 are critical for fruit growth and development. Further, characterization of several genes involved in GA-signalling showed that their transcriptional regulation are generally GA-dependent, confirming their involvement in GA-signalling. Based on these results, a model is presented elucidating how the potential association between GA and other hormones may contribute to fruit development. PslGID1 proteins structure, Y2H and BiFC assays indicated that plum GA-receptors can form a complex with AtDELLA-repressors in a GA-dependent manner. Moreover, phenotypical-, molecular- and GA-analyses of various Arabidopsis backgrounds ectopically expressing PslGID1 sequences provide evidence on their role as active GA-signalling components that mediate GA-responsiveness. Our findings support the critical contribution of GA alone or in association with other hormones in mediating plum fruit growth and development.

Structure-activity relations of 2-(methylthio)benzimidazole by FTIR, FT-Raman, NMR, DFT and conceptual DFT methods

The vibrational fundamental modes of 2-(methylthio)benzimidazole (2MTBI) have been analysed by combining FTIR, FT-Raman and quantum chemical calculations. The structural parameters of the compound are determined from the optimised geometry by B3LYP with 6-31G(∗∗), 6-311++G(∗∗) and cc-pVTZ basis sets and giving energies, harmonic vibrational frequencies, depolarisation ratios, IR intensities and Raman activities. (1)H and (13)C NMR spectra have been analysed and (1)H and (13)C nuclear magnetic resonance chemical shifts are calculated using the gauge independent atomic orbital (GIAO) method. The structure-activity relationship of the compound is also investigated by conceptual DFT methods. The chemical reactivity and site selectivity of the molecule has been determined with the help of global and local reactivity descriptors.

Exploring the structure-activity relations of N-carbethoxyphthalimide by combining FTIR, FT-Raman and NMR spectroscopy with DFT electronic structure method

The complete vibrational assignment and analysis of N-carbethoxyphthalimide were carried out using the experimental FTIR and FT-Raman data in the range 4000-450 and 4000-100 cm(-1), respectively along with quantum chemical studies of the compound using DFT-B3LYP gradient calculations employing the 6-31G**, 6-311++G** and cc-pVDZ basis sets. The 1H (400 MHz; CDCl3) and 13C (100 MHz;CDCl3) nuclear magnetic resonance (NMR) spectra were also recorded. Due to the partial ionic nature of the carbonyl group, the carbon atoms C1 and C3 in NCEP show downfield effect and the corresponding observed chemical shift of both are observed at 163.76 ppm and the carbon atom C16 in the carbethoxy group also give signal in the downfield at 148.45 ppm. The active sites are determined by molecular electrostatic potential. The possible electronic transitions are determined by HOMO and LUMO orbital shapes and their energies. The structure-chemical reactivity relations of the compound were determined through chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors by conceptual DFT methods.

A comparative study on vibrational, conformational and electronic structure of 1,2-dimethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole

The FTIR and FT-Raman spectra of 1,2-dimethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole have been recorded in the regions 4000-400 and 4000-100 cm(-1), respectively. The conformational analyses were performed and the energies of the different possible conformers were determined. The geometry of different conformers of the compounds were optimised with B3LYP and B3PW91 methods using 6-311++G and aug-cc-pVTZ basis sets to characterise all stationary points as minima. The optimised structural parameters of the most stable conformer were used in the vibrational frequency calculations. The Raman activities were also determined with B3LYP method using 6-311++G basis sets. The force constants obtained from the B3LYP/6-311++G method have been utilised in the normal coordinate analysis. The temperature dependence of the thermodynamic properties heat capacity at constant pressure (C(p)), entropy (S) and enthalpy change (ΔH(0→T)) for both the compounds were also determined by B3LYP/6-311++G method. The total electron density and MESP surfaces of the molecules were constructed by NBO analysis using B3LYP/6-311++G method to display electrostatic potential (electron+nuclei) distribution, molecular shape, size, and dipole moments of the molecule. The electronic properties HOMO and LUMO energies were measured. The influences of nitro and methyl groups on the skeletal modes have been investigated.

Insights into the molecular mechanism of RGL2-mediated inhibition of seed germination in Arabidopsis thaliana

BACKGROUND

Seed germination is of immense significance for agriculture and has been studied for centuries. Yet, our understanding of the molecular mechanisms underlying regulation of dormancy and germination is still in its infancy. Gibberellins are the key phytohormones that promote germination, and the DELLA protein RGL2 is the main signalling intermediate involved in this response. Germination is completely inhibited if functional RGL2 is overexpressed and/or stabilized; however, the molecular mechanisms of RGL2 function are still largely unknown. We therefore attempted to shed light onto some of the genetic events downstream of RGL2.

RESULTS

Gene ontology of the transcriptome differentially regulated by RGL2, as well as extensive cross-comparison with other available microarray data indicates that RGL2-mediated inhibition of germination causes seeds to enter a state of dormancy. RGL2 also appears to differentially regulate a number of transcription factors, many of which are known to be involved in light- or phytohormone-mediated aspects of germination. A promoter analysis of differentially expressed genes identified an enrichment of several motifs that can be bound by specific transcription factors, for example GAMYB, ARF1, or Dof-type zinc fingers. We show that Dof-binding motifs indeed play a role in RGL2-mediated transcription. Using Chromatin Immunoprecipitation (ChIP), we show that RGL2 directly downregulates at least one cell wall modifying enzyme, which is predicted to constrain cell growth thereby leading to inhibition of seed germination.

CONCLUSIONS

Our results reveal that RGL2 controls various aspects of germination. Through the repression of cell wall modifying enzymes, cell growth is directly constrained to inhibit germination. Furthermore, RGL2 likely interacts with various types of proteins to regulate transcription, and differentially regulates several transcription factors. Collectively, our data indicate that gibberellins, acting via RGL2, control several aspects of seed germination.

Panel 2.2: Surveillance, Early Warning Alert, and Response: Communicable and Vector-Borne Diseases

This is a summary of the presentations and discussion of Surveillance, Early Warning Alert and Response at the Conference, Health Aspects of the Tsunami Disaster in Asia, convened by the World Health Organization (WHO)in Phuket, Thailand, 04–06 May 2005. The topics discussed included issues related to the surveillance, early warning alert, and response to communicable and vector-borne diseases as pertaining to the responses to the damage created bythe Tsunami. It is presented in the following major sections: (1) key questions; (2) needs assessment; (3) coordination(4) gap filling; and (5) capacity building. The key questions section is presented in six sub-sections: (1) communicable diseases; (2) early warning; (3) laboratory capacity and referral networking; (4) coordination of disease surveillance, early warning, and response; (5) health infrastructure rebuilding; and (6) using existing national surveillance plans toenhance disease surveillance and early warning systems.

Session 1.2: National Health Perspectives of the Tsunami Crisis

This is a summary of the presentations and discussion of Session 1.2 of the Conference, Health Aspects of the Tsunami Disaster in Asia, convened by the World Health Organization (WHO) in Phuket, Thailand, 04–06 May 2005. The topics discussed included issues related national health perspectives as pertaining to the responses to the damage created by the Tsunami. It is presented in the following major sections: (1) key questions; (2) discussion; (3) what was done well?; (4) what could have been done better?; and (5) what can be done to prepare for the future?.

Structural, vibrational and quantum chemical investigations on 5-chloro-2-hydroxybenzamide and 5-chloro-2-hydroxybenzoic acid

The Fourier transform infrared (FTIR) and FT-Raman spectra of 5-chloro-2-hydroxybenzamide (5CBA) and 5-chloro-2-hydroxybenzoic acid (5C2HBA) have been recorded in the range 4000-400 and 4000-100 cm(-1), respectively. The complete vibrational fundamental modes of the compounds were assigned and analysed using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally were compared with the theoretical wavenumbers calculated from ab initio HF and DFT-B3LYP gradient methods employing 6-31G** and 6-311++G** basis sets. The effect of halogen, hydroxyl groups and hydrogen bonding on the characteristic frequencies of the -COOH and -CONH2 group frequencies have been investigated. In 5CBA and 5C2HBA intramolecular hydrogen bond between a hydroxyl group and CO group makes a six membered ring, which causes the O⋯H interaction onto the resonance of the benzene ring. Comparison of the positions of the ν(OH) bands shows the ν(OH) band of 5CBA is located at considerably higher frequency which confirms a weaker hydrogen bond than in 5C2HBA.

Nano-phases of NaBH4 and KBH4

Phase stability and chemical bonding of beta-NaBH4 and beta-KBH4 derived nano-structures and possible low energy surfaces of them from thin film geometry have been investigated using ab initio projected augmented plane wave method. Structural optimizations based on total energy calculations predicted that, for beta-NaBH4 and beta-KBH4 phases, the (011) and (101) surfaces are more stable among the possible low energy surfaces. The predicted critical size of the nano-cluster for beta-NaBH4 and beta-KBH4 is 1.35 and 1.8 nm, respectively. The corresponding critical diameter for the nano-whisker is 2.6 and 2.8 nm respectively for beta-NaBH4 and beta-KBH4. Structural optimization based on total energy calculations show that the bond distances in the surfaces of nano-whisker are found to be higher than that in the bulk material and the calculated H site energies and bond overlap population analysis suggesting that it is considerably easier to remove hydrogen from the surface of the clusters and nano-whiskers than that from the bulk crystals.

FTIR, FT-Raman, ab initio and density functional studies on 4-methyl-1,3-dioxolan-2-one and 4,5-dichloro-1,3-dioxolan-2-one

The Fourier transform infrared (FTIR) and FT-Raman spectra of 4-methyl-1,3-dioxolan-2-one and 4,5-dichloro-1,3-dioxolan-2-one have been recorded in the range 3700-400 and 3700-100 cm(-1), respectively. The complete vibrational assignment and analysis of the fundamental modes of the compounds were carried out using the observed FTIR and FT-Raman data. The vibrational frequencies determined experimentally were compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing 6-311++G** and cc-pVTZ basis sets for the optimised geometries of the compounds. The geometries and normal modes of vibration obtained from the HF and DFT methods are in good agreement with the experimental data. The normal coordinate analysis was also carried out with ab initio force fields utilising Wilson's FG matrix method. The interactions of the skeletal vibrational modes were investigated.

Structural investigation and thermodynamical properties of alkali calcium trihydrides

The ground-state structure, equilibrium structural parameters, electronic structure, and thermodynamical properties of MCaH(3) (M=Li, Na, K, Rb, and Cs) phases have been investigated. From the 104 structural models used as inputs for structural optimization calculations, the ground-state crystal structures of MCaH(3) phases have been predicted. At ambient condition, LiCaH(3), NaCaH(3), and KCaH(3) crystallize in hexagonal, monoclinic, and orthorhombic structures, respectively. The remaining phases RbCaH(3) and CsCaH(3) crystallize in a cubic structure. The calculated phonon spectra indicate that all the predicted phases are dynamically stable. The formation energy for the MCaH(3) phases have been calculated along different reaction pathways. The electronic structures reveal that all these phases are insulators with an estimated band gap varying between 2.5 and 3.3 eV.

Phase stability and pressure-induced structural transitions at zero temperature in ZnSiO(3) and Zn(2)SiO(4)

Using density functional total energy calculations the structural phase stability and pressure-induced structural transition in different polymorphs of ZnSiO(3) and Zn(2)SiO(4) have been studied. Among the considered monoclinic phase with space groups (P 2(1)/c) and (C 2/c), rhombohedral [Formula: see text] and orthorhombic (Pbca) modifications the monoclinic phase (P 2(1)/c) of ZnSiO(3) is found to be the most stable one. At high pressure monoclinic ZnSiO(3) (C 2/c) can co-exist with orthorhombic (Pbca) modification. Differences in equilibrium volume and total energy of these two polymorphs are very small, which indicates that it is relatively easier to transform between these two phases by temperature, pressure or chemical composition. It can also explain the experimentally established result of metastability of the orthorhombic phase under all conditions. The following sequence of pressure-induced structural phase transitions is found for ZnSiO(3) polymorphs: monoclinic [Formula: see text] monoclinic [Formula: see text] rhombohedral [Formula: see text]. Among the rhombohedral ([Formula: see text]), tetragonal [Formula: see text], orthorhombic (Pbca), orthorhombic (Imma), cubic [Formula: see text] and orthorhombic (Pbnm) modifications of Zn(2)SiO(4), the rhombohedral phase is found to be the ground state. For this chemical composition of zinc silicate the following sequence of structural phase transitions is found: rhombohedral [Formula: see text] tetragonal [Formula: see text] orthorhombic [Formula: see text] orthorhombic (Imma) [Formula: see text] cubic [Formula: see text] orthorhombic (Pbnm). Based on the analogy of crystal structures of magnesium and zinc silicates and using the lattice and positional parameters of Mg(2)SiO(4) as input, structural properties of spinel Zn(2)SiO(4) have also been studied.

Quantum chemical and spectroscopic investigations of 5-aminoquinoline

The Fourier transform infrared (FTIR) and FT-Raman spectra of 5-aminoquinoline (5AQ) have been recorded in the range 4000-400 and 3500-100 cm(-1), respectively. The complete vibrational assignment and analysis of the fundamental modes of the compounds were carried out using the observed FTIR and FT-Raman data. (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by using the gauge independent atomic orbital (GIAO) method. UV-vis spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The geometric parameters, chemical shifts and absorption wavelengths were compared with the experimental data of the molecule. The vibrational frequencies which were determined experimentally are compared with those obtained theoretically from ab initio HF and DFT-B3LYP gradient calculations employing the 6-31G** and 6-311++G** basis sets for optimized geometries of the compound. The interactions of NH-pi and the influence of amino group on the skeletal modes are investigated.

Synthesis, structural, vibrational and quantum chemical investigations of N-(2-methylphenyl)-2,2-dichloroacetamide and N-(4-methylphenyl)-2,2-dichloroacetamide

N-(2-Methylphenyl)-2,2-dichloroacetamide (2MPA) and N-(4-methylphenyl)-2,2-dichloroacetamide (4MPA) of the configuration X(y)C(6)H(5-y)-NHCO-CHCl(2) (where, X=CH(3) and y=1) were synthesised and an extensive spectroscopic investigations have been carried out by recording the Fourier transform infrared (FTIR) and FT-Raman spectra and subjecting them to normal co-ordinate analysis, in an effort to provide mixing of the fundamental modes with the help of potential energy distribution (PED). The ab initio and DFT studies were carried out with 6-311++G(d,p) basis set to determine the structural, thermodynamical and vibrational characteristics of the compounds and also to understand the steric influence of methyl group on the characteristic frequencies of amide (-CONH-) group.

Structural, vibrational and DFT studies on 2-chloro-1H-isoindole-1,3(2H)-dione and 2-methyl-1H-isoindole-1,3(2H)-dione

The Fourier transform infrared (FTIR) and FT-Raman spectra of 2-chloro-1H-isoindole-1,3(2H)-dione and 2-methyl-1H-isoindole-1,3(2H)-dione have been measured in the range of 4000-400 and 4000-100 cm(-1), respectively. Complete vibrational assignment and analysis of the fundamental modes of the compounds were performed using the observed FTIR and FT-Raman data. The geometry was optimised without any symmetry constraints using the DFT/B3LYP method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The vibrational frequencies determined experimentally are compared with those obtained theoretically from DFT gradient calculations employing the B3LYP/6-31G(d,p) and B3LYP/6-311++G(d,p) methods for the optimised geometry of the compounds. The structural parameters and normal modes of vibration obtained from DFT method are in good agreement with the experimental data. The force fields obtained from DFT method were utilised and the potential energy distributions of all the fundamental vibrations of the compounds were calculated.