Rice husk valorisation by in situ grown MoS2 nanoflowers: a dual-action catalyst for pollutant dye remediation and microbial decontamination

Rice husk (RH) is a common agricultural waste generated during the rice milling process; however, a major portion is either burned or disposed of in landfills, posing significant environmental risks. In this study, RH waste was transformed into bio-based catalysts via delignification cum in situ growth of MoS2 (DRH-MoS2) for efficient pollutant dye removal and microbial decontamination. The developed DRH-MoS2 exhibits nanoflower-like structures with a 2H-MoS2 phase and a narrow band gap of 1.37 eV, which showed strong evidence of photocatalytic activity. With the presence of abundant hydroxyl functionality, delignified rice husk (DRH) exhibits a malachite green (MG) dye adsorption capacity of 88 mg g-1. However, in situ growth of MoS2 nanosheets on DRH enhances MG degradation to 181 mg g-1 under dark conditions and 550 mg g-1 in the presence of light. Mechanistic insights reveal a synergistic adsorption-cum-degradation phenomenon, amplified by generation of reactive oxygen species during photodegradation which was confirmed from radical scavenging activity. Interestingly, DRH-MoS2 demonstrates potent antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with sustained photodegradation efficiency (>80%) over three cycles. The present work reports a cost-effective and scalable strategy for environmental remediation of real wastewater which usually contains both dye pollutants as well as microbes using abundantly available renewable resources such as sunlight and agricultural biomass wastes.

Mapping of adult plant recessive resistance to anthracnose in Indian common bean landrace Baspa/KRC 8

BACKGROUND

The common bean (Phaseolus vulgaris) has become the food of choice owing to its wealthy nutritional profile, leading to a considerable increase in its cultivation worldwide. However, anthracnose has been a major impediment to production and productivity, as elite bean cultivars are vulnerable to this disease. To overcome barriers in crop production, scientists worldwide are working towards enhancing the genetic diversity of crops. One way to achieve this is by introducing novel genes from related crops, including landraces like KRC 8. This particular landrace, found in the North Western Himalayan region, has shown adult plant resistance against anthracnose and also possesses a recessive resistance gene.

METHODS AND RESULTS

In this study, a population of 179 F2:9 RIL individuals (Jawala × KRC 8) was evaluated at both phenotypic and genotypic levels using over 830 diverse molecular markers to map the resistance gene present in KRC 8. We have successfully mapped a resistance gene to chromosome Pv01 using four SSR markers, namely IAC 238, IAC 235, IAC 259, and BM 146. The marker IAC 238 is closely linked to the gene with a distance of 0.29 cM, while the other markers flank the recessive resistance gene at 10.87 cM (IAC 259), 17.80 cM (BM 146), and 25.22 cM (IAC 235). Previously, a single recessive anthracnose resistance gene (co-8) has been reported in the common bean accession AB 136. However, when we performed PCR amplification with our tightly linked marker IAC 238, we got different amplicons in AB 136 and KRC 8. Interestingly, the susceptible cultivar Jawala produced the same amplicon as AB 136. This observation indicated that the recessive gene present in KRC 8 is different from co-8. As the gene is located far away from the Co-1 locus, we suggest naming the recessive gene co-Indb/co-19. Fine mapping of co-Indb in KRC 8 may provide new insights into the cloning and characterization of this recessive gene so that it can be incorporated into future bean improvement programs. Further, the tightly linked marker IAC 238 can be utilized in marker assisted introgression in future bean breeding programs.

CONCLUSION

The novel co-Indb gene present in Himalayan landrace KRC 8, showing adult plant resistance against common bean anthracnose, is independent from all the resistance genes previously located on chromosome Pv01.

Identification of nitric oxide mediated defense signaling and its microRNA mediated regulation during Phytophthora capsici infection in black pepper

Nitric oxide plays a significant role in the defense signaling during pathogen interaction in plants. Quick wilt disease is a devastating disease of black pepper, and leads to sudden mortality of pepper vines in plantations. In this study, the role of nitric oxide was studied during Phytophthora capsici infection in black pepper variety Panniyur-1. Nitric oxide was detected from the different histological sections of P. capsici infected leaves. Furthermore, the genome-wide transcriptome analysis characterized typical domain architect and structural features of nitrate reductase (NR) and nitric oxide associated 1 (NOA1) gene that are involved in nitric oxide biosynthesis in black pepper. Despite the upregulation of nitrate reductase (Pn1_NR), a reduced expression of Pn1_NOA1 was detected in the P. capsici infected black pepper leaf. Subsequent sRNAome-assisted in silico analysis revealed possible microRNA mediated regulation of Pn1_NOA mRNAs. Furthermore, sRNA/miRNA mediated cleavage on Pn1_NOA1 mRNA was validated through modified 5' RLM RACE experiments. Several hormone-responsive cis-regulatory elements involved in stress response was detected from the promoter regions of Pn_NOA1, Pn_NR1 and Pn_NR2 genes. Our results revealed the role of nitric oxide during stress response of P. capsici infection in black pepper, and key genes involved in nitric oxide biosynthesis and their post-transcriptional regulatory mechanisms.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01414-z.

Association of obstructive sleep apnea and sleep quality with cognitive function: a study of middle-aged and elderly persons in India

INTRODUCTION

Symptoms of obstructive sleep apnea (OSA) and poor sleep quality affect around one in ten people in India. We aimed to determine if OSA symptoms and poor sleep quality are independently associated with cognition in middle-aged and elderly urban Indian populations.

METHODS

We studied the cross-sectional association between OSA symptoms (by Berlin Questionnaire), poor sleep quality (by Pittsburgh Sleep Quality Index), and cognitive function in adults ≥ 50 years. Using a standard neuropsychological battery for cognitive function, a G-factor was derived as the first rotated principal component assessing domains of information processing, memory, and executive function. The associations of exposures with cognitive measures were modeled using linear regression, adjusted for metabolic risk factors, lifestyle factors, and psychosocial problems, followed by stratified analysis by decadal age group.

RESULTS

A total of 7505 adults were enrolled. Excluding those with MMSE < 26 (n 710), of 6795 individuals (49.2% women), mean (SD) age 64.2 (9.0) years, 38.3% had high risk of OSA symptoms, and 15.9% had poor sleep quality. OSA symptoms were negatively associated with cognitive domains of information processing (adjusted beta coefficient of z-score - 0.02, p-value 0.006), memory (- 0.03, 0.014), and G-factor (- 0.11, 0.014) in full-model. Stratified analysis by age group showed significant adverse effects of OSA symptoms on cognition for middle-aged people (50-60 years) (- 0.26, 0.001), but not in later age groups. Poor sleep quality was also associated with lower cognitive scores for G-factor (- 0.48, < 0.001), memory (- 0.08, 0.005), and executive domains (- 0.12, < 0.001), but not with information domain.

CONCLUSION

The findings suggest that both symptoms of OSA and poor sleep quality have a direct adverse impact on cognition in an Indian setting. A modest effect of age on the relationship of OSA and cognition was also observed.

Mitochondria-targeted biotin-conjugated BODIPYs for cancer imaging and therapy

Two BODIPY-biotin conjugates KDP1 and KDP2 are designed and synthesized for targeted PDT applications. Both have good absorption with a high molar absorption coefficient and decent singlet oxygen generation quantum yields. The photosensitizers KDP1 and KDP2 were found to be localized in the mitochondria with excellent photocytotoxicity of up to 18.7 nM in MDA-MB-231 breast cancer cells. The cell death predominantly proceeded through the apoptosis pathway via ROS production.

Cholesterol regulates insulin-induced mTORC1 signaling

The rapid activation of the crucial kinase mechanistic target of rapamycin complex-1 (mTORC1) by insulin is key to cell growth in mammals, but the regulatory factors remain unclear. Here, we demonstrate that cholesterol plays a crucial role in the regulation of insulin-stimulated mTORC1 signaling. The rapid progression of insulin-induced mTORC1 signaling declines in sterol-depleted cells and restores in cholesterol-repleted cells. In insulin-stimulated cells, cholesterol promotes recruitment of mTORC1 onto lysosomes without affecting insulin-induced dissociation of the TSC complex from lysosomes, thereby enabling complete activation of mTORC1. We also show that under prolonged starvation conditions, cholesterol coordinates with autophagy to support mTORC1 reactivation on lysosomes thereby restoring insulin-responsive mTORC1 signaling. Furthermore, we identify that fibroblasts from individuals with Smith-Lemli-Opitz Syndrome (SLOS) and model HeLa-SLOS cells, which are deficient in cholesterol biosynthesis, exhibit defects in the insulin-mTORC1 growth axis. These defects are rescued by supplementation of exogenous cholesterol or by expression of constitutively active Rag GTPase, a downstream activator of mTORC1. Overall, our findings propose novel signal integration mechanisms to achieve spatial and temporal control of mTORC1-dependent growth signaling and their aberrations in disease.