Causes and consequences of tipping points in river delta social-ecological systems.

The sustainability of social-ecological systems within river deltas globally is in question as rapid development and environmental change trigger "negative" or "positive" tipping points depending on actors' perspectives, e.g. regime shift from abundant sediment deposition to sediment shortage, agricultural sustainability to agricultural collapse or shift from rural to urban land use. Using a systematic review of the literature, we show how cascading effects across anthropogenic, ecological, and geophysical processes have triggered numerous tipping points in the governance, hydrological, and land-use management of the world's river deltas. Crossing tipping points had both positive and negative effects that generally enhanced economic development to the detriment of the environment. Assessment of deltas that featured prominently in the review revealed how outcomes of tipping points can inform the long-term trajectory of deltas towards sustainability or collapse. Management of key drivers at the delta scale can trigger positive tipping points to place social-ecological systems on a pathway towards sustainable development.

Aligning the Global Delta Risk Index with SDG and SFDRR global frameworks to assess risk to socio-ecological systems in river deltas.

River deltas globally are highly exposed and vulnerable to natural hazards and are often over-exploited landforms. The Global Delta Risk Index (GDRI) was developed to assess multi-hazard risk in river deltas and support decision-making in risk reduction interventions in delta regions. Disasters have significant impacts on the progress towards the Sustainable Development Goals (SDGs). However, despite the strong interlinkage between disaster risk reduction and sustainable development, global frameworks are still developed in isolation and actions to address them are delegated to different institutions. Greater alignment between frameworks would both simplify monitoring progress towards disaster risk reduction and sustainable development and increase capacity to address data gaps in relation to indicator-based assessments for both processes. This research aims at aligning the GDRI indicators with the SDGs and the Sendai Framework for Disaster and Risk Reduction (SFDRR). While the GDRI has a modular indicator library, the most relevant indicators for this research were selected through a delta-specific impact chain designed in consultation with experts, communities and stakeholders in three delta regions: the Red River and Mekong deltas in Vietnam and the Ganges-Brahmaputra-Meghna (GBM) delta in Bangladesh and India. We analyse how effectively the 143 indicators for the GDRI match (or not) the SDG and SFDRR global frameworks. We demonstrate the interconnections of the different drivers of risk to better inform risk management and in turn support delta-level interventions towards improved sustainability and resilience of these Asian mega-deltas. Supplementary Information: The online version contains supplementary material available at 10.1007/s11625-023-01295-3.

Development of SSR markers and construction of a linkage map in jute.

Jute is an important natural fibre crop, which is only second to cotton in its importance at the global level. It is mostly grown in Indian subcontinent and has been recently used for the development of genomics resources.We recently initiated a programme to develop simple sequence repeat markers and reported a set of 2469 SSR that were developed using four SSR-enriched libraries (Mir et al. 2009). In this communication, we report an additional set of 607 novel SSR in 393 SSR containing sequences. However, primers could be designed for only 417 potentially useful SSR. Polymorphism survey was carried out for 374 primer pairs using two parental genotypes (JRO 524 and PPO4) of a mapping population developed for fibre fineness; only 66 SSR were polymorphic. Owing to a low level of polymorphism between the parental genotypes and a high degree of segregation distortion in recombinant inbred lines, genotypic data of only 53 polymorphic SSR on the mapping population consisting of 120 RIL could be used for the construction of a linkage map; 36 SSR loci were mapped on six linkage groups that covered a total genetic distance of 784.3 cM. Hopefully, this map will be enriched with more SSR loci in future and will prove useful for identification of quantitative trait loci/genes for molecular breeding involving improvement of fibre fineness and other related traits in jute.

Identification and characterization of a FYVE domain from the early diverging eukaryote Giardia lamblia.

The morphology of the endomembrane system of Giardia lamblia appears to be significantly different from higher eukaryotes. Therefore, the molecular mechanisms controlling vesicular trafficking are also likely to be altered. Since FYVE domain is a known regulator of endosomal trafficking, the authors used BLAST search to identify FYVE domain(s) in G. lamblia. A 990 amino acid long putative FYVE domain-containing ORF was identified, which contains all the conserved sequence elements in the ligand binding pocket. Phylogenetic analysis reveals that this domain is significantly diverged. The authors have shown that the corresponding gene is expressed in G. lamblia trophozoites and cysts. In spite of this phylogenetic divergence, in vitro biochemical assay indicates that this domain preferentially binds to phosphatidylinositol 3-phosphate {PtdIns(3)P}and in vivo expression of the GFP-tagged G. lamblia FYVE domain in S. cerevisiae, displays its selective localization to PtdIns(3)P-enriched endosomes. This is the first study to characterize a PtdIns(3)P effector protein in this early-diverged eukaryote.

Vitamin C prevents cigarette smoke induced atherosclerosis in guinea pig model.

AIM: Cigarette smoking is a major risk for developing atherosclerosis; however, the underlying mechanism is poorly understood. This paucity of knowledge is largely attributed to the lack of an animal model; therefore, our efforts were targeted towards establishing cigarette smoke (CS)-induced atherosclerosis in guinea pig. To understand the mechanism, we investigated apoptosis, an event implicated in atherosclerosis, in the aorta of CS-exposed animals. Since a major deleterious effect of CS is oxidative stress, we also examined the effect of vitamin C, an antioxidant, on CS- induced atherosclerosis. METHODS AND RESULTS: Guinea pigs on a diet with or without vitamin C supplement were exposed to CS for different time periods. Aortal sections from these animals were examined for atherosclerotic changes by staining with H&E and Oil red O. Atherogenic changes were observed in sections obtained from CS-exposed guinea pigs only. TUNEL assay showed the occurrence of apoptosis in CS-exposed guinea pig aorta. Our results revealed that CS-induced apoptosis could contribute to the progression but not to the initiation of the disease. Immunohistochemical analysis documents that CS-induced apoptosis in aortal sections is mediated at least in part by an increased Bax/Bcl2 ratio. In contrast, CS-exposed guinea pigs fed with vitamin C-supplemented diet exhibit little or no atherogenic changes. This anti-atherosclerotic activity of vitamin C can be attributed partly to its ability to inhibit CS-induced apoptosis and platelet activation. CONCLUSION: Exposure of guinea pigs to cigarette smoke causes the development of atherosclerosis, which can be prevented by vitamin C supplement.

Comparative genomics reveals selective distribution and domain organization of FYVE and PX domain proteins across eukaryotic lineages.

BACKGROUND: Phosphatidylinositol 3-phosphate is involved in regulation of several key cellular processes, mainly endocytosis, signaling, nuclear processes, cytoskeletal remodelling, cell survival, membrane trafficking, phagosome maturation and autophagy. In most cases effector proteins bind to this lipid, using either FYVE or PX domain. These two domains are distributed amongst varied life forms such as virus, protists, fungi, viridiplantae and metazoa. As the binding ligand is identical for both domains, the goal of this study was to understand if there is any selectivity for either of these domains in different taxa. Further, to understand the different cellular functions that these domains may be involved in, we analyzed the taxonomic distribution of additional domains that associate with FYVE and PX. RESULTS: There is selectivity for either FYVE or PX in individual genomes where both domains are present. Fungi and metazoa encode more PX, whereas streptophytes in viridiplantae encode more FYVE. Excess of FYVE in streptophytes results from proteins containing RCC1and DZC domains and FYVE domains in these proteins have a non-canonical ligand-binding site. Within a taxonomic group the selected domain associates with a higher number of other domains and is thus expected to discharge a larger number of cellular functions. Also, while certain associated domains are present in all taxonomic groups, most of them are unique to a specific group indicating that while certain common functions are discharged by these domains in all taxonomic groups, some functions appear to be group specific. CONCLUSIONS: Although both FYVE and PX bind to PtdIns(3)P, genomes of different taxa show distinct selectivity of encoding either of the two. Higher numbers of taxonomic group specific domains co-occur with the more abundant domain (FYVE/PX) indicating that group-specific rare domain architectures might have emerged to accomplish certain group-specific functions.

On the quantum theory of electron transfer: effect of potential surfaces of the reactants and products.

In this study the electron transfer theory for the high frequency intramolecular mode and low frequency medium mode has been rederived using different methods. For a single-mode case when the reactant surface is not in a thermal equilibrium but in a thermocoherent state the authors have derived the rate and discussed about the quantum features of the rate. In the limit of very low and very high temperatures the expressions are derived analytically and compared with the case of thermal distribution. Secondly, a Franck-Condon factor for a multimode displaced, distorted, and Duschinsky rotated adiabatic potential surfaces has been derived to obtain the rate. Lastly, a systematic investigation is made to show the temperature dependence on the rate due to displacement, distortion, and Duschinsky rotation of the harmonic potential energy surfaces of the reactant and product manifold.

Laser cooling of vibrational degrees of freedom of a molecular system.

We consider the cooling of vibrational degrees of freedom in a photoinduced excited electronic state of a model molecular system. For the various parameters of the potential surfaces of the ground and excited electronic states and depending on the excitation frequency of a single-mode laser light, the average energy or average vibrational temperature of the excited state passes through a minimum. The amount of cooling is quantified in terms of the overlap integral between the ground and excited electronic states of the molecule. We have given an approach to calculate the Franck-Condon factor for a multimode displaced-distorted-rotated oscillator surface of the molecular system. This is subsequently used to study the effect of displacement, distortion, and Duschinsky rotation on the vibrational cooling in the excited state. The absorption spectra and also the average energy or the effective temperature of the excited electronic state are studied for the above model molecular system. Considering the non-Condon effect for the symmetry-forbidden transitions, we have discussed the absorption spectra and average temperature in the excited-state vibrational manifold.

Radiative decay of nonstationary system.

When a finite quantum system, say a fluorescent molecule is attached to a bulk surface and excited by a short laser pulse, the decay dynamics of the system is modulated by the surface and the signal is enhanced due to the bulk surface. We have considered the decay dynamics of a model of displaced distorted molecule whose excited potential surface is coupled to a continuum and then this first continuum is in turn coupled to a second continuum. In the short time scale there is a coherent exchange of energy between the system molecule and the first continuum states. In the long time scale the energy of the whole system plus first continuum drains out to the final continuum states. A dendrimer nanocomposite with the gold surface shows an enhanced light emission. This can be qualitatively understood from the model we proposed here. We have numerically studied the various potential parameters of the molecule which can affect the signal. When the potential surfaces are flat, the band structure of the first continuum states along with its initial excitation has some nontrivial effect on the profile of the radiative decay.