Subcellular optogenetic inhibition of G proteins generates signaling gradients and cell migration

Cells sense gradients of extracellular cues and generate polarized responses such as cell migration and neurite initiation. There is static information on the intracellular signaling molecules involved in these responses, but how they dynamically orchestrate polarized cell behaviors is not well understood. A limitation has been the lack of methods to exert spatial and temporal control over specific signaling molecules inside a living cell. Here we introduce optogenetic tools that act downstream of native G protein–coupled receptor (GPCRs) and provide direct control over the activity of endogenous heterotrimeric G protein subunits. Light-triggered recruitment of a truncated regulator of G protein signaling (RGS) protein or a Gβγ-sequestering domain to a selected region on the plasma membrane results in localized inhibition of G protein signaling. In immune cells exposed to spatially uniform chemoattractants, these optogenetic tools allow us to create reversible gradients of signaling activity. Migratory responses generated by this approach show that a gradient of active G protein αi and βγ subunits is sufficient to generate directed cell migration. They also provide the most direct evidence so for a global inhibition pathway triggered by Gi signaling in directional sensing and adaptation. These optogenetic tools can be applied to interrogate the mechanistic basis of other GPCR-modulated cellular functions

Polyaniline/palladium nanohybrids for moisture and hydrogen detection.

Palladium nanoparticles display fascinating electronic, optical and catalytic properties, thus they can be used for various applications such as sensor fabrication. Conducting polymers such as polyaniline have also been widely used in sensor technology due to its cost effectiveness, versatility, and ease of synthesis. In this research, attention was given to unify the exceptional properties of these two materials and construct palladium nanoparticle coated polyaniline films to detect hydrogen and moisture. Electrochemical polymerization of aniline was carried out on gold sputtered epoxy resin boards. Polyaniline film was generated across a gap of 0.2 mm created by a scratch made on the gold coating prior to electrochemical polymerization. A palladium nanoparticle dispersion was prepared using sonochemical reduction method and coated on to polyaniline film using drop-drying technique. Polyaniline only films were also fabricated for comparative analysis. Sensitivity of films towards humidity and hydrogen was evaluated using impedance spectroscopy in the presence of the respective species. According to the results, polyaniline films exhibited an impedance drop in the presence of humidity and the response was significantly improved once palladium nanoparticles were incorporated. Interestingly, polyaniline only films did not respond to hydrogen. Nevertheless, palladium nanoparticle coated polyaniline films exhibited remarkable response towards hydrogen

Photosynthetic Phenomics of Field- and Greenhouse-Grown Amaranths vs. Sensory and Species Delimits

Consumers hesitate to purchase field-grown shoot-tops of amaranths in Sri Lanka, citing the low-cleanliness making growers focus on greenhouse farming. However, the photosynthetic and growth variations in relation to the organoleptic preference of the greenhouse-grown amaranths in comparison to field-grown counterparts have not been studied. Also, the species delimits of the amaranths in Sri Lanka have not been identified, limiting our ability to interpret species-specific production characteristics. Thus, we assessed the common types of amaranths under greenhouse and field conditions. The photosynthesis was measured using a MultispeQ device of the PhotosynQ phenomic platform, which records chlorophyll fluorescence-based parameters. The shoot-tops were harvested and prepared as dishes according to the typical recipe for amaranths in Sri Lanka. The dishes were subjected to an organoleptic assessment for the parameters color, aroma, bitterness, texture, and overall taste. The differences in plant and the shoot-top biomass were also assessed. The markers atpB-rbcL, matk-trnT, and ITS were used to define the species delimits. The field-grown and greenhouse-grown amaranths exhibited species/cultivar-specific photosynthetic variations. The texture and overall taste of the dishes were different among greenhouse and field-grown material. The tasters preferred the texture and the overall taste of the greenhouse-grown shoot-tops. The greenhouse-grown plants also yielded higher shoot-top harvests compared to field-grown counterparts. Out of the tested markers, ITS defines the delimits of amaranth species. The higher organoleptic preference, the appreciable yield levels, unique photosynthetic patterns of the greenhouse-grown amaranths, and species definitions provide the much-needed platform for clean shoot-top production guaranteeing the highest end-user trust

Young elephants in a large herd maintain high levels of elephant endotheliotropic herpesvirus-specific antibodies and do not succumb to fatal haemorrhagic disease

Elephant endotheliotropic herpesviruses (EEHVs) have co-existed with elephants for millions of years, yet may cause fatal haemorrhagic disease (EEHV-HD), typically in elephants between 1 and 10 years of age. EEHV is omnipresent in (sub)adult elephants, and young elephants with low EEHV-specific antibody levels are at risk for EEHV-HD, suggesting that fatal disease may occur due to an insufficiently controlled primary infection. To further address this hypothesis, sera of three large elephant cohorts were subjected to a multiple EEHV species ELISA: (I) 96 Asian elephants between 0 and 57 years, including 13 EEHV-HD fatalities, from European zoo herds typically sized five to six elephants, (II) a herd of 64 orphaned elephants aged 0–15 years at the Elephant Transit Home in Sri Lanka and (III) 31 elephants aged 8–63 years, part of a large herd of 93 elephants at Pinnawala Elephant Orphanage, Sri Lanka. All Sri Lankan elephants showed high EEHV-specific antibody levels regardless of their age. While antibody levels of most European zoo elephants were comparable to those of Sri Lankan elephants, the average antibody level of the European juveniles (1–5 years of age) was significantly lower than those of age-matched Sri Lankan individuals. Moreover, the European juveniles showed a gradual decrease between 1 and 4 years of age, to be attributed to waning maternal antibodies. Maintenance of high levels of antibodies in spite of waning maternal antibodies in young Sri Lankan elephants is likely due to the larger herd size that increases the likelihood of contact with EEHV-shedding elephants. Together with the observation that low levels of EEHV-specific antibodies correlate with increased numbers of EEHV-HD fatalities, these results suggest that infection in presence of high maternal antibody levels may protect calves from developing EEHV-HD, while at the same time activating an immune response protective in future encounters with this virus

Assessment of the association between yield parameters and polymorphic sites of the <i>Ghd7</i> locus in a core-set of rice cultivars grown in Sri Lanka

Yield improvement is a major aspect in rice breeding programs. Ghd7 is a pleiotropic gene which regulates yield, plant height, and heading date in rice. Although Ghd7 has been previously cloned and sequenced in several other rice cultivars, none of the studies have been conducted for Sri Lankan rice germplasm. Therefore, in this study, we assessed the yield performance of 12 rice cultivars, genetic polymorphism of Ghd7 locus and associations between DNA markers and yield traits. Breeder seeds of the selected cultivars were obtained from RRDI, Bathalagoda, and established under greenhouse conditions at Peradeniya, Sri Lanka in Maha and Yala seasons, 2017. The cultivars were subjected to morphometric analysis, genotyped for 12 DNA markers and sequenced at Seq7-8 locus. Morphometric data were subjected to single marker analysis using General Linear Model (GLM) in SAS 9.4. Here we reported six marker haplotypes based on the arrangement of 13 DNA maker alleles at Ghd7. Moreover, twenty-three SNP/INDEL variations at Seq7-8 locus revealed close genetic relationships between the rice cultivars Bg 90-2, Bg 352 and At 307, Bg310. Four polymorphic markers (Seq7-8, Seq1-2, RM5436 and RM5346) were significantly associated with rice yield traits so that they could be used in marker assisted selection. The SNPs/INDELs of Ghd7 were significantly associated with all the yield traits except 100 seed weight and 100 endosperm weight. Thus the present study demonstrate the possibility of employing marker assisted breeding to improve rice yield using the polymorphic genomic information at Ghd7 locus

Disease awareness, pharmacological adherence, and knowledge on further advanced therapeutic option among medically managed postmyocardial infarction patients: Experience from a Sri Lankan tertiary care cardiac center

Context: Although most of the patients with ischemic heart diseases (IHD) are treated according to the guidelines, adequacy of the knowledge about their treatment is questionable. Aims: The study was aimed to explore the patients' awareness of their disease, state of pharmacological adherence, and the knowledge of their further advance therapeutic options on patients who were subjected to medical management following myocardial infarction (MI). Settings and Design: This study design was a cross-sectional descriptive study. Subjects and Methods: The study was conducted at Cardiology Unit, Teaching Hospital Kandy, Sri Lanka in 2015. Pretested interviewer-administered questionnaire and patients' health records were used to collect the data. All the patients who had MI and currently on medical management were included in the study. Patients who had a percutaneous coronary intervention and coronary artery bypass graft surgeries were excluded from the study. Statistical Analysis Used: Data analysis was performed by SPSS version 19 statistical package. P < 0.05 was considered statistically significant. Results: A total number of 103 patients with a mean age of 58 ± 9 years were included in the study. According to the four-item Morisky Medication Adherence Scale, 51.5% had high adherence to treatments, whereas moderate and low adherences were reported in 42.7% and 5.8%, respectively. The mean number of drugs in polymedicated patients was 7.5 ± 1.6. Only 28% had the awareness about the type of their IHD by pathophysiology in simple terms. Only 33% had discussed the necessity of advanced therapeutic options following their acute coronary event. Conclusions: Suboptimal drug adherence, lack of knowledge about their disease, and inadequacy of health communication are the major issues to be addressed in our post-MI patients

Assessing causes of quality deterioration of groundwater in Puttalam, Sri Lanka, using isotope and hydrochemical tools^†

<p>Extensive extraction of groundwater has resulted in deterioration of the groundwater quality in the Puttalam area in the northwestern coastal zone of Sri Lanka. This situation led us to carry out the present comprehensive study based on environmental isotopic (¹⁸O, ²H, ³H) and geochemical evaluation to understand the root cause for water quality deterioration. The isotopic data suggest that the surface water and shallow groundwaters are subjected to intensive evaporation and, as a result, increase in their salinity. Deep groundwater of the area is mostly recharged by direct infiltration of rainwater and at few places by nearby surface water bodies. The salinity increase of deep groundwater depends on the specific hydrogeological zones and would be due to dissolution of salts which are precipitated in soil through the seawater spray over the time, dissolution of minerals in geological matrix and leaching of salts from salterns. The quality of the deep groundwater is relatively good in the granitic gneiss zone and nearby areas outside the sedimentary aquifer. There is no evidence from isotope and hydrogeochemical evaluation for seawater intrusion into groundwater in the Puttalam area.</p