A mouse transgenic approach to induce ��-catenin signaling in a temporally controlled manner

Although constitutive murine transgenic models have provided important insights into β-catenin signaling in tissue morphogenesis and tumorigenesis, these models are unable to express activated β-catenin in a temporally controlled manner. Therefore, to enable the induction (and subsequent de-induction) of β-catenin signaling during a predetermined time-period or developmental stage, we have generated and characterized a TETO-ΔN89β-catenin responder transgenic mouse. Crossed with the MTB transgenic effector mouse, which targets the expression of the reverse tetracycline transactivator (rtTA) to the mammary epithelium, we demonstrate that the stabilized (and activated) form of β-catenin (ΔN89β-catenin) is expressed only in the presence doxycycline-activated rtTA in the mammary epithelial compartment. Furthermore, we show that transgene-derived ΔN89β-catenin elicits significant mammary epithelial proliferation and precocious alveologenesis in the virgin doxycycline-treated MTB/TETO-ΔN89β-catenin bitransgenic. Remarkably, deinduction of TETO-ΔN89β-catenin transgene expression (through doxycycline withdrawal) results in the reversal of these morphological changes. Importantly, continued activation of the TETO-ΔN89β-catenin transgene results in palpable mammary tumors (within 7-9?months) in the doxycycline-treated virgin MTB/TETO-ΔN89β-catenin bigenic but not in the same bitransgenic without doxycycline administration. Collectively, these mammary epithelial responses to ΔN89β-catenin expression agree with previous reports using conventional transgenesis and therefore confirm that ΔN89β-catenin functions as expected in this doxycycline-responsive bigenic system. In sum, our mammary gland studies demonstrate "proof-of-principle" for using the TETO-ΔN89β-catenin transgenic responder to activate (and then de-activate) β-catenin signaling in any tissue of interest in a spatiotemporal specific fashion.     

Thrombin-like serine protease,antiquorin from Euphorbia antiquorum latex induces platelet aggregation via PAR1-Akt/p38 signaling axis

Plant latex proteases (PLPs) are pharmacologically essential and are integral components of traditional medicine in the management of bleeding wounds. PLPs are known to promote blood coagulation and stop bleeding by interfering at various stages of hemostasis. There are a handful of scientific reports on thrombin-like enzymes characterized from plant latices. However, the role of plant latex thrombin-like enzymes in platelet aggregation is not well known. In the present study, we attempted to purify and characterize thrombin-like protease responsible for platelet aggregation. Among tested plant latices, Euphorbia genus latex protease fractions (LPFs) induced platelet aggregation. In Euphorbia genus, E. antiquorum LPF (EaLPF) strongly induced platelet aggregation and attenuated bleeding in mice. The purified thrombin-like serine protease, antiquorin (Aqn) is a glycoprotein with platelet aggregating activities that interfere in intrinsic and common pathways of blood coagulation cascade and alleviates bleeding and enhanced excision wound healing in mice. In continuation, the pharmacological inhibitor of PAR1 inhibited Aqn-induced phosphorylation of cPLA₂, Akt, and P38 in human platelets. Moreover, Aqn-induced platelet aggregation was inhibited by pharmacological inhibitors of PAR1, PI3K, and P38. These data indicate that PAR1-Akt/P38 signaling pathways are involved in Aqn-induced platelet aggregation. The findings of the present study may open up a new avenue for exploiting Aqn in the treatment of bleeding wounds.     

Hypoxia‐induced localization of chemotaxis‐related signaling proteins in Vibrio cholerae

Vibrio cholerae has three sets of chemotaxis‐related signaling proteins, of which only System II has been shown to be involved in chemotaxis. Here, we examined localization of green fluorescent protein (GFP)‐fused components of System I. The histidine kinase (CheA1) and the adaptor (CheW0) of System I localized to polar and lateral membrane regions with standing incubation (microaerobic conditions), but their localization was lost after shaking (aerobic conditions). A transmembrane receptor of System I also showed polar and lateral localization with standing incubation. By contrast, GFP‐fused components of System II localized constitutively to the flagellated pole. Nitrogen gas, sodium azide or carbonylcyanide m‐chlorophenylhydrazone induced localization of CheA1‐GFP even with shaking incubation, suggesting that the localization is controlled in response to changes in energy metabolism. Fluorescently labeled tetracysteine‐tagged CheA1 also showed azide‐induced localization, arguing against artifactual effects of GFP fusions. These results suggest that System I components are assembled into the supramolecular signaling complex in response to reduced cellular energy states, raising the possibility that the System I complex plays a role in sensing and signaling under microaerobic environments, such as in the host intestine.     

Sustainable livelihood security index in a developing country: A tool for development planning

The paper presents an overview of the existing indicators of development and positions them within the environmental, economic, and social dimensions of sustainable development. It presents empirical evidence of sustainable livelihood security index (SLSI) at the district level in Gujarat. SLSI is a composite index having three component indices, i.e. the ecological security index (ESI), the economic efficiency index (EEI), and the social equity index (SEI). It finds that the SLSI based on its simplicity and flexibility, is one of the most comprehensive yet simple indices for measuring long-term livelihood security in rural areas. For instance, the eastern districts of the state, dominated by scheduled tribes’ population have very low EEI and SEI rankings, although they have high ESI ranking. These districts also have very low ranks in gender development index, education index, health index and housing index. Thus, the SLSI not only identifies the general priorities for development but also the nature and types of policies to be pursued in each study unit to enhance livelihood security. The SLSI facilitates consensus among different partisan groups like economists, environmentalists, and egalitarians by balancing their mutual concerns, could provide guidelines for achieving sustainable development. It can function as an educational and a policy tool for promoting a holistic perspective among planners, administrators, and development workers.     

Genetic differentiation, recombination and clonal expansion in environmental populations of Cryptococcus gattii in India

Cryptococcus gattii is a ubiquitous eukaryotic pathogen capable of causing life-threatening infections in a wide variety of hosts, including both immunocompromised and immunocompetent humans. Since infections by C. gattii are predominantly obtained from environmental exposures, understanding environmental populations of this pathogen is critical, especially in countries like India with a large population and with environmental conditions conducive for the growth of C. gattii. In this study, we analysed 109 isolates of C. gattii obtained from hollows of nine tree species from eight geographic locations in India. Multilocus sequence typing was conducted for all isolates using nine gene fragments. All 109 isolates belonged to the VGI group and were mating type α. Population genetic analyses revealed limited evidence of recombination but unambiguous evidence for clonal reproduction and expansion. However, the observed clonal expansion has not obscured the significant genetic differentiation among populations from either different geographic areas or different host tree species. A positive correlation was observed between genetic distance and geographic distance. The results obtained here for environmental populations of C. gattii showed both similarities and differences with those of the closely related Cryptococcus neoformans var. grubii from similar locations and host tree species in India.     

The impact of utilizing different optical coherence tomography devices for clinical purposes and in multiple sclerosis trials

Optical coherence tomography (OCT) derived retinal measures, particularly peri-papillary retinal nerve fiber layer (RNFL) thickness, have been proposed as outcome measures in remyelinating and neuroprotective trials in multiple sclerosis (MS). With increasing utilization of multiple centers to improve power, elucidation of the impact of different OCT technologies is crucial to the design and interpretation of such studies. In this study, we assessed relation and agreement between RNFL thickness and total macular volume (in MS and healthy controls) derived from three commonly used OCT devices: Stratus time-domain OCT, and Cirrus HD-OCT and Spectralis, two spectral-domain (SD) OCT devices. OCT was performed on both Cirrus HD-OCT and Stratus in 229 participants and on both Cirrus HD-OCT and Spectralis in a separate cohort of 102 participants. Pearson correlation and Bland-Altman analyses were used to assess correlation and agreement between devices. All OCT retinal measures correlated highly between devices. The mean RNFL thickness was 7.4 μm lower on Cirrus HD-OCT than Stratus, indicating overall poor agreement for this measurement between these machines. Further, the limits of agreement (LOA) between Cirrus HD-OCT and Stratus were wide (-4.1 to 18.9 μm), indicating poor agreement at an individual subject level. The mean RNFL thickness was 1.94 μm (LOA: -5.74 to 9.62 μm) higher on Spectralis compared to Cirrus HD-OCT, indicating excellent agreement for this measurement across this cohort. Although these data indicate that these three devices agree poorly at an individual subject level (evidenced by wide LOA in both study cohorts) precluding their co-utilization in everyday practice, the small difference for mean measurements between Cirrus HD-OCT and Spectralis indicate pooled results from these two SD-devices could be used as outcome measures in clinical trials, provided patients are scanned on the same machine throughout the trial, similar to the utilization of multiple different MRI platforms in MS clinical trials.