Molecular profiling in relation to drought tolerance in advance breeding lines of rice using microsatellite markers

Using agro-morphological characters and microsatellite markers, advance breeding lines of rice were discriminated for their ability to tolerate drought stress at reproductive stage. Experimental materials consisting of 17 advance breeding lines and a check were evaluated in randomized block design with three replications under irrigated condition and drought condition created under rainout shelter during three consecutive years. An analysis of variance revealed significant differences among the genotypes for all the ten agro-morphological characters evaluated under both the conditions across the years. Principal component analysis showed the relative importance of root length, number of tillers per plant, number of grains per panicle, harvest index and grain yield per plant among agro-morphological characters and stress tolerance level, stress susceptibility index, stress tolerance index and drought tolerance efficiency among drought tolerance indices as the important classification variables. Relative mean performance in respect of grain yield as well as drought tolerance indices reflected remarkably greater degree of drought tolerance in 11 advance breeding lines and the check, discriminating them from remaining entries under evaluation. Utilizing a panel of 32 microsatellite primers, selective amplification of targeted genomic regions revealed that the primers RM 72, RM 163, RM 212, RM 225, RM 231, RM 302, RM 327, RM 518, RM 521, RM 555, RM 1349, RM 3549 and RM 5443 were highly informative with greater gene diversity and discrimination ability. Hierarchical cluster analysis based on molecular profiles discriminated the entries into five genotypic groups and drought tolerant entries were accommodated into three distinct groups with remarkably greater efficiency (85.7%). Principal coordinate analysis based two dimensional plots of microsatellites dependent genetic profiles displayed a very close correspondence with the genotypic clustering pattern revealed from a perusal of dendrogram. Sequential exclusion of primers in cluster analysis led to identification of RM 212, RM 231, RM 324, RM 431, RM 521, RM 3549 and RM 6374 as the most useful primers for discrimination of drought tolerant and susceptible lines of rice. Molecular profiling based on these markers can be utilized as efficient tools for discrimination and identification of drought tolerant lines.

     

Plant regeneration in cotton: A short-term inositol starvation promotes developmental synchrony in somatic embryogenesis

Summary Despite high commercial interest, the success of biotechnological applications in cotton (Gossypium hirsutum) has been limited due to difficulties in genetic transformation. Major problems have been genotype dependence and low frequency of somatic embryogenesis, making it difficult to regenerate plants from transgenic tissue. This study reports an increase in somatic embryogenesis efficiency and the induction of developmental synchrony in embryogenic callus cultures of cotton by a single cycle of myo-inositol depletion in liquid culture. Calluses were initiated on hypocotyl or cotyledon explants of cultivar Coker 312 by culturing these explants on callus-inducing solid medium [Murashige and Skoog salts plus vitamins of Gamborg's B₅ medium, 30 g l⁻¹ glucose, 100 mg l⁻¹ myo-inositol, 2.2 μM 2,4-dichlorophenoxyacetic acid, and 0.88 μM 6-benzyladenine]. The calluses were transferred to an identical liquid basal medium devoid of plant growth regulators. This induced the development of embryogenic cells. Friable clumps of cells formed after 20 d in the medium were selectively collected over filter mesh 40 subjected to one cycle of myo-inositol starvation. This induced a highly synchronized embryogenesis in the culture. The optimized protocol gave 100% embryos at the globular stage, out of which more than 80% developed into bipolar torpedo-stage embryos. About 68% of these were converted to plantlets by subculturing onto a simplified solid medium, and finally grown into healthy, fertile plants.     

Synthesis and properties of a water soluble graft (chitosan-g-2-acrylamidoglycolic acid) copolymer

The present paper reports the graft copolymerization of 2-acrylamidoglycolic acid onto chitosan by using potassium bromate/silver nitrate as an efficient redox initiator in an inert atmosphere. The effect of reaction conditions on grafting parameters i.e. grafting ratio, efficiency, conversion, add on, homopolymer and rate of grafting has been studied. Experimental results show that maximum grafting has been obtained at 0.4 g dm(-3) concentration of chitosan, 8.0×10(-2) mol dm(-3) concentration of 2-acrylamidoglycolic acid and 1.0×10(-3) mol dm(-3) concentration of hydrogen ion. It has also been observed that grafting ratio, add on, conversion, efficiency and rate of grafting increase up to 3.2×10(-3) mol dm(-3) of silver nitrate and 1.7×10(-2) mol dm(-3) of potassium bromate. Time (120 min) and temperature (40°C) were kept constant during reaction. The physicochemical properties of graft copolymer synthesized have been performed in terms of water swelling, metal ion sorption, flocculation and resistance to biodegradability with respect to the chitosan as a parent polymer. The graft copolymer has been characterized by Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis.     

The SET domain protein, Set3p, promotes the reliable execution of cytokinesis in Schizosaccharomyces pombe

In response to perturbation of the cell division machinery fission yeast cells activate regulatory networks that ensure the faithful completion of cytokinesis. For instance, when cells are treated with drugs that impede constriction of the actomyosin ring (low doses of Latrunculin A, for example) these networks ensure that cytokinesis is complete before progression into the subsequent mitosis. Here, we identify three previously uncharacterized genes, hif2, set3, and snt1, whose deletion results in hyper-sensitivity to LatA treatment and in increased rates of cytokinesis failure. Interestingly, these genes are orthologous to TBL1X, MLL5, and NCOR2, human genes that encode components of a histone deacetylase complex with a known role in cytokinesis. Through co-immunoprecipitation experiments, localization studies, and phenotypic analysis of gene deletion mutants, we provide evidence for an orthologous complex in fission yeast. Furthermore, in light of the putative role of the complex in chromatin modification, together with our results demonstrating an increase in Set3p levels upon Latrunculin A treatment, global gene expression profiles were generated. While this analysis demonstrated that the expression of cytokinesis genes was not significantly affected in set3Δ backgrounds, it did reveal defects in the ability of the mutant to regulate genes with roles in the cellular response to stress. Taken together, these findings support the existence of a conserved, multi-protein complex with a role in promoting the successful completion of cytokinesis.     

Pollen morphology of Basmati cultivars (Oryza sativa race Indica) – exine surface ultrastructure

Pollen morphological studies using LM and SEM have been carried out on six cultivars of Basmati – a variety of cultivated species Oryza sativa race Indica. SEM study at a magnification of ×20,000 revealed distinct variations in pollen exine surface patterns, in relation to the arrangements of fine surface excrescences (spinules or granules) and their clustering patterns forming small areas or insulae. Three distinctly different insular patterns occur in cultivars Basmati-370, Karnal local and Type-9. Cultivar Bakul Joha is characterized by free spinules. Mixed type i.e. both free and fused excrescences were observed in cultivars Bengali Joha and Bhog Maniki but they can be differentiated on the basis of the dimensions of the excrescences.     

Simulation of LV pacemaker lead in marginal vein: potential risk factors for acute dislodgement

Although left ventricular (LV) coronary sinus lead dislodgement remains a problem, the risk factors for dislodgement have not been clearly defined. In order to identify potential risk factors for acute lead dislodgement, we conducted dynamic finite element simulations of pacemaker lead dislodgement in marginal LV vein. We considered factors such as mismatch in lead and vein diameters, velocity of myocardial motion, branch angle between the insertion vein and the coronary sinus, degree of slack, and depth of insertion. The results show that large lead-to-vein diameter mismatch, rapid myocardial motion, and superficial insertion are potential risk factors for lead dislodgement. In addition, the degree of slack presents either a positive or negative effect on dislodgement risk depending on the branch angle. The prevention of acute lead dislodgment can be enforced by inducing as much static friction force as possible at the lead-vein interface, while reducing the external force. If the latter exceeds the former, dislodgement will occur. The present findings underscore the major risk factors for lead dislodgment, which may improve implantation criterion and future lead design.     

Evaluation of a community-based mobile video breastfeeding intervention in Khayelitsha,South Africa: The Philani MOVIE cluster-randomized controlled trial

BackgroundIn South Africa, breastfeeding promotion is a national health priority. Regular perinatal home visits by community health workers (CHWs) have helped promote exclusive breastfeeding (EBF) in underresourced settings. Innovative, digital approaches including mobile video content have also shown promise, especially as access to mobile technology increases among CHWs. We measured the effects of an animated, mobile video series, the Philani MObile Video Intervention for Exclusive breastfeeding (MOVIE), delivered by a cadre of CHWs (“mentor mothers”).Methods and findingsWe conducted a stratified, cluster-randomized controlled trial from November 2018 to March 2020 in Khayelitsha, South Africa. The trial was conducted in collaboration with the Philani Maternal Child Health and Nutrition Trust, a nongovernmental community health organization. We quantified the effect of the MOVIE intervention on EBF at 1 and 5 months (primary outcomes), and on other infant feeding practices and maternal knowledge (secondary outcomes). We randomized 1,502 pregnant women in 84 clusters 1:1 to 2 study arms. Participants’ median age was 26 years, 36.9% had completed secondary school, and 18.3% were employed. Mentor mothers in the video intervention arm provided standard-of-care counseling plus the MOVIE intervention; mentor mothers in the control arm provided standard of care only. Within the causal impact evaluation, we nested a mixed-methods performance evaluation measuring mentor mothers’ time use and eliciting their subjective experiences through in-depth interviews.At both points of follow-up, we observed no statistically significant differences between the video intervention and the control arm with regard to EBF rates and other infant feeding practices [EBF in the last 24 hours at 1 month: RR 0.93 (95% CI 0.86 to 1.01, P = 0.091); EBF in the last 24 hours at 5 months: RR 0.90 (95% CI 0.77 to 1.04, P = 0.152)]. We observed a small, but significant improvement in maternal knowledge at the 1-month follow-up, but not at the 5-month follow-up. The interpretation of the results from this causal impact evaluation changes when we consider the results of the nested mixed-methods performance evaluation. The mean time spent per home visit was similar across study arms, but the intervention group spent approximately 40% of their visit time viewing videos. The absence of difference in effects on primary and secondary endpoints implies that, for the same time investment, the video intervention was as effective as face-to-face counseling with a mentor mother. The videos were also highly valued by mentor mothers and participants. Study limitations include a high loss to follow-up at 5 months after premature termination of the trial due to the COVID-19 pandemic and changes in mentor mother service demarcations.ConclusionsThis trial measured the effect of a video-based, mobile health (mHealth) intervention, delivered by CHWs during home visits in an underresourced setting. The videos replaced about two-fifths of CHWs’ direct engagement time with participants in the intervention arm. The similar outcomes in the 2 study arms thus suggest that the videos were as effective as face-to-face counselling, when CHWs used them to replace a portion of that counselling. Where CHWs are scarce, mHealth video interventions could be a feasible and practical solution, supporting the delivery and scaling of community health promotion services.Trial registrationThe study and its outcomes were registered at clinicaltrials.gov (#{"type":"clinical-trial","attrs":{"text":"NCT03688217","term_id":"NCT03688217"}}NCT03688217) on September 27, 2018.

Maya Adam and colleagues study a video intervention, delivered by community health workers, to promote breastfeeding in South Africa.     

Myosin-II reorganization during mitosis is controlled temporally by its dephosphorylation and spatially by Mid1 in fission yeast

Cytokinesis in many eukaryotes requires an actomyosin contractile ring. Here, we show that in fission yeast the myosin-II heavy chain Myo2 initially accumulates at the division site via its COOH-terminal 134 amino acids independently of F-actin. The COOH-terminal region can access to the division site at early G2, whereas intact Myo2 does so at early mitosis. Ser1444 in the Myo2 COOH-terminal region is a phosphorylation site that is dephosphorylated during early mitosis. Myo2 S1444A prematurely accumulates at the future division site and promotes formation of an F-actin ring even during interphase. The accumulation of Myo2 requires the anillin homologue Mid1 that functions in proper ring placement. Myo2 interacts with Mid1 in cell lysates, and this interaction is inhibited by an S1444D mutation in Myo2. Our results suggest that dephosphorylation of Myo2 liberates the COOH-terminal region from an intramolecular inhibition. Subsequently, dephosphorylated Myo2 is anchored by Mid1 at the medial cortex and promotes the ring assembly in cooperation with F-actin.     

The gametic algebra for polyploidy with several loci

In this paper it is shown that the genetic algebra of an infinitely large random mating population of polyploid individuals which differ at n linked loci, between which recombination may occur, is a genetic algebra.It has been assumed that at every locus there is a finite number of alleles and there is an arbitrary amount of double reduction.