Rice with SUB1 QTL possesses greater initial leaf gas film thickness leading to delayed perception of submergence stress

Background and AimsSubmergence tolerance in rice is primarily attributed to the action of the SUB1 gene, but other associated traits such as leaf gas film (LGF) thickness, leaf hydrophobicity, porosity and leaf density have been known to aid submergence tolerance in rice. However, association of these traits with SUB1 quantitative trait locus (QTL) has not been demonstrated. In this study, we aim to investigate (1) whether the presence of the SUB1 QTL in the genetic background has any influence on the thickness of the LGF and (ii) whether its removal has any impact on stress perception and submergence tolerance in Sub1 and non-Sub1 rice.MethodsWe examined 12 genotypes (including both Sub1 and non-Sub1 types) for different leaf traits such as initial LGF thickness, leaf hydrophobicity, tissue porosity and leaf density in order to work out the relatioship of these traits to the SUB1 QTL in rice. Furthermore, we investigated the changes in the gene expression profile and different metabolic processes in selected genotypes in the presence and absence of their LGF to study its impact on stress perception and adaptation.Key ResultsThe initial thickness of the LGF and hydrophobicity seemed to have a highly positive correlation with the presence of the SUB1 QTL in the genetic background of rice; however, other leaf traits such as porosity and density seemed to be independent of it. Artificial removal of the LGF resulted in partial loss of tolerance, showing increased ethylene production and early induction of anoxia-related genes (SUB1A-1, ACS5, Ramy3D and ADH1) which manifested symptoms such as increased stem elongation, faster chlorophyll and starch breakdown, and partial loss of quiescence in SUB1-containing rice genotypes. Stripping of the LGF resulted in early and enhanced induction of SUB1A-1, indicating a quicker perception of stress.ConclusionsThe presence of SUB1 in the genetic background positively influences surface hydrophobicity and the concomitant LGF thickness of rice. Furthermore, LGF helps in terms of providing better ethylene dissipation and reduced in planta accumulation, owing to the slowing down of ethylene-induced leaf senescence under submergence stress.     

Time to move: winds and the political economy of space in Andamanese culture

Seasons, or temporal duration, for Andamanese are created by the flow of winds through the Andamanese cultural construct of space, which is neither fixed nor constant. In order to organize the space for society, Andaman islanders have to move constantly out from the place where the winds are. Winds associated with temperamental spirits are powerful aspects of nature that culture has to negotiate. Within this worldview where winds affect individual body condition and the capacity to continue hunting and gathering, Andaman islanders negotiate space by creating conditions that invite winds to structure and sustain life. For this purpose, smells are ritualized and wind movements are manipulated. As a result, seasons are distinguished either by winds that are spirit-given, or by a lack of winds caused by islanders' actions. Based on ethnographic data from the Ongees and Jarwas, this analysis will focus on how various forms of movement in Andamanese culture are negotiated according to a political economy of winds and smells. The worldview of the Andaman islanders, within which winds are so central, has major implications for government authorities, who are keen to confine the translocating Jarwas to a specific and permanent location. But is this possible for the Andamanese, for whom space, like time, changes by the presence and absence of winds?     

Gangliosides Inhibit Glucosylceramide Synthase: A Possible Role in Ganglioside Therapy

Gangliosides stimulate the hydrolysis of glucosylceramide (GlcCer), their precursor, and therefore may lower the level of cellular GlcCer and exert a feedback control effect to slow the formation of gangliosides. Tests were made to see if a similar effect on GlcCer levels can be exerted by the action of gangliosides on GlcCer synthesis. Using a new assay procedure, we showed that gangliosides do inhibit the synthase in brain membranes quite effectively, the most active being those lipids with more sugar and sialic acid moieties. Mice injected with a mixture of brain gangliosides for 5 days were found to have a lower level of ceramide:UDP-Glc glucosyltransferase activity in brain, liver, and kidney. The inhibition seems to be exerted by competition for the active site and binding to effector site(s) on the enzyme. It is possible that the reported therapeutic actions of gangliosides on the nervous system are, in part, the result of lowered levels of GlcCer. Malignant tumors shed gangliosides into the extracellular fluid, which are believed to block the generation of antibodies by the host's immunodefense system; this effect also may be due, in part, to reduction in the GlcCer level of immunogenic cells. A new finding is that a ceramide containing phytosphingosine is a markedly better substrate for GlcCer synthase than one containing the more common base.     

Assessment of Pulmonary Function in Young and Elderly Shift Workers of a Steel Plant

The present investigation was undertaken to examine the effects of shift work on pulmonary function. 217 subjects from a local steel plant, volunteered for this study. Of these, 65 were day workers (DWs) and 152 were shift workers (SWs). Pulmonary function, such as vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁), peak expiratory flow rate (PEFR) and percent deviation of PEFR from the expected PEFR in each subject was measured between 09:00 to 11:00. Both day workers (DWs) and shift workers (SWs) were divided into two groups, based on age, i.e., ≤ 40 y and ≥ 41 y. The results indicate that the average levels of VC, FVC, FEV₁ and PEFR were significantly lower in older age in both DWs and SWs when compared to their younger counterparts. Although elderly shift workers had higher levels of VC, FVC and FEV₁ than day workers of comparable age, the difference was not statistically significant for FVC and FEV₁. In contrast, average value of PEFR was lower in older shift workers. Further, mean percent deviation of observed PEFR from the expected value was conspicuously low in elderly shift workers. In summary, shift work appears to accelerate age-related decline in PEFR at least in elderly shift workers. Results of multiple regression analysis and correlation analysis compliment this finding.