Occurrence, distribution and sources of petroleum contamination in reef-associated sediments of the Gulf of Mannar, India.

The distribution of saturated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) was assessed in superficial sediment samples collected from Mandapam island groups, Gulf of Mannar, India. The hydrocarbon distribution pattern and the n-alkane indices (e.g., carbon preference index (CPI) and natural n-alkanes ratio (NAR)) were deployed to differentiate between the biogenic and anthropogenic sources. Petroleum pollution was indicated by the pristane/phytane ratio close to 1. Presence of a prominent unresolved complex mixture (UCM) as well as hopane concentrations further supported this assertion. The evaluation of petrogenic sources of contamination were also comprehended by various diagnostic ratios of PAHs. The sites associated with shipping activities, tourism, and located near the mainland and accessible portions of the islands exhibited high petroleum contamination. Correlation analysis underlines the significance of combining petroleum-specific marker compounds and diagnostic ratios to improve the assessment of human influence on marine ecosystems.

The ORNATE India Project: United Kingdom-India Research Collaboration to tackle visual impairment due to diabetic retinopathy.

INTRODUCTION: The ORNATE India project is funded by the UK Research and Innovation (UKRI) through the Global Challenges Research Fund. The aim is to build research capacity and capability in India and the UK to tackle global burden of diabetes-related visual impairment. As there are over 77 million people with diabetes in India, it is challenging to screen every person with diabetes annually for sight-threatening diabetic retinopathy (DR). Therefore, alternate safe approaches need to be developed so that those at-risk of visual impairment due to DR is identified promptly and treated. METHODS: The project team utilised diverse global health strategies and research methods to co-design work packages to build research capacity and capability to ensure effective, affordable and efficient DR services are made available for the population. The strategies and methods employed included health system strengthening; implementation science; establishing care pathways; co-designing collaborative studies on affordable technologies, developing quality standards and guidelines to decrease variations in care; economic analysis; risk modelling and stratification. Five integrated work packages have been developed to deal with all aspects of DR care. These included implementation of a DR screening programme in the public health system in a district in Kerala, evaluating regional prevalence of diabetes and DR and assessing ideal tests for holistic screening for diabetes and its complications in 20 areas in India, utilising artificial intelligence on retinal images to facilitate DR screening, exploring biomarker and biosensor research to detect people at risk of diabetes complications, estimating cost of blindness in India and risk modelling to develop risk-based screening models for diabetes and its complications. A large collaborative network will be formed to propagate research, promote shared learning and bilateral exchanges between high- and middle-income countries to tackle diabetes-related blindness.

Influence of mixotrophic growth on rhythmic oscillations in expression of metabolic pathways in diazotrophic cyanobacterium Cyanothece sp. ATCC 51142.

This study investigates the influence of mixotrophy on physiology and metabolism by analysis of global gene expression in unicellular diazotrophic cyanobacterium Cyanothece sp. ATCC 51142 (henceforth Cyanothece 51142). It was found that Cyanothece 51142 continues to oscillate between photosynthesis and respiration in continuous light under mixotrophy with cycle time of ∼ 13 h. Mixotrophy is marked by an extended respiratory phase compared with photoautotrophy. It can be argued that glycerol provides supplementary energy for nitrogen fixation, which is derived primarily from the glycogen reserves during photoautotrophy. The genes of NDH complex, cytochrome c oxidase and ATP synthase are significantly overexpressed in mixotrophy during the day compared to autotrophy with synchronous expression of the bidirectional hydrogenase genes possibly to maintain redox balance. However, nitrogenase complex remains exclusive to nighttime metabolism concomitantly with uptake hydrogenase. This study throws light on interrelations between metabolic pathways with implications in design of hydrogen producer strains.

Evaluation of an animal protein-free semen extender for cryopreservation of epididymal sperm from North American bison (Bison bison).

The objective was to evaluate the suitability of an animal protein-free semen extender for cryopreservation of epididymal sperm from the two subspecies of North American bison: plains (Bison bison bison) and wood (Bison bison athabascae) bison. Both cauda epididymides (from six plains and five wood bison) were minced and incubated in Sp-TALPH buffer for approximately 2 h at 37 °C to release actively motile sperm. Sperm suspensions were filtered, centrifuged and the sperm pellet from each bull was divided into two fractions and diluted either in egg yolk containing extender, Triladyl, or in an animal protein-free extender, Andromed, and equilibrated for 20 min at 37 °C. Thereafter, samples were chilled and cryopreserved. Frozen-thawed sperm were evaluated for motility (computer assisted sperm analysis), viability (SYBR 14 and propidium iodide), acrosome integrity (FITC conjugated PSA), cryocapacitation (tyrosine phosphorylation of sperm proteins as a biomarker), and fertilizing ability (in a heterologous IVF system). There was no significant difference for progressive motility, viability, and acrosome integrity between the two extenders for plains bison (36.8 ± 9.0, 60.5 ± 17.4, and 77.3 ± 4.6%; overall mean ± SD) as well as for wood bison (11.7 ± 8.1, 13.7 ± 5.6, and 73.4 ± 4.2%). Levels of tyrosine phosphorylation did not differ for sperm preserved in the two extenders for both subspecies, although an inter-bull variability in the response to tyrosine phosphorylation between extenders was suggested for plains bison. Fertilization percent did not differ significantly between extenders for plains bison (84.16 ± 9.92%, overall mean ± SD) and for wood bison (59.53 ± 19.99%). In conclusion, in the absence of significant difference between extenders in post-thaw sperm characteristics, we inferred that Andromed (animal protein-free) was suitable for cryopreservation of epididymal sperm from North American bison.

Extragenic suppressors of the arabidopsis zwi-3 mutation identify new genes that function in trichome branch formation and pollen tube growth.

The plant cytoskeleton plays a pivotal role in determining the direction of cell wall expansion, and ultimately the cell's final shape. However, the mechanisms by which localized expansion events are initiated remain obscure. Mutational analysis of the trichome (plant hair) morphogenic pathway in Arabidopsis has identified at least eight genes that determine trichome branch number. One of these genes, ZWICHEL (ZWI), encodes a novel member of the kinesin superfamily of motor proteins. Mutations in the ZWI gene cause a reduction in the number of trichome branches. To identify additional genes involved in trichome branch initiation, we screened for extragenic suppressors of the zwi-3 mutation and isolated three suppressors that rescued the branch number defect of zwi-3. These suppressors define three genes, named suz, for suppressor of zwichel-3. All of the suppressors were shown to be allele specific. One of the suppressors, suz2, also rescued the trichome branch number defect of another branch mutant, furca1-2. Plants homozygous for suz2 have more than the wild-type number of trichome branches. This suggests that SUZ2 is a negative regulator of trichome branching and may interact with ZWI and FURCA1. The suz1 and suz3 mutants display no obvious phenotype in the absence of the zwi-3 mutation. The suz1 zwi-3 double mutants also exhibited a male-sterile phenotype due to a defect in pollen tube germination and growth, whereas both the suz1 and the zwi-3 single mutants are fertile. The synthetic male sterility of the suz1 zwi-3 double mutants suggests a role for SUZ1 and ZWI in pollen germination and pollen tube growth. DNA sequence analysis of the zwi-3 mutation indicated that only the tail domain of the zwi-3 protein would be expressed. Thus, the suz mutations show allele-specific suppression of a kinesin mutant that lacks the motor domain.