Phylogenetic diversity of Mesorhizobium in chickpea

Crop domestication, in general, has reduced genetic diversity in cultivated gene pool of chickpea (Cicer arietinum) as compared with wild species (C. reticulatum, C. bijugum). To explore impact of domestication on symbiosis, 10 accessions of chickpeas, including 4 accessions of C. arietinum, and 3 accessions of each of C. reticulatum and C. bijugum species, were selected and DNAs were extracted from their nodules. To distinguish chickpea symbiont, preliminary sequences analysis was attempted with 9 genes (16S rRNA, atpD, dnaJ, glnA, gyrB, nifH, nifK, nodD and recA) of which 3 genes (gyrB, nifK and nodD) were selected based on sufficient sequence diversity for further phylogenetic analysis. Phylogenetic analysis and sequence diversity for 3 genes demonstrated that sequences from C. reticulatum were more diverse. Nodule occupancy by dominant symbiont also indicated that C. reticulatum (60%) could have more various symbionts than cultivated chickpea (80%). The study demonstrated that wild chickpeas (C. reticulatum) could be used for selecting more diverse symbionts in the field conditions and it implies that chickpea domestication affected symbiosis negatively in addition to reducing genetic diversity.     

Drought induces many forms of cysteine proteases not observed during natural senescence

Drought-induced senescence and natural senescence was characterised in the cowpea leaf, with a focus on cysteine proteases. Soluble protein content and ribulose 1,5-bisphosphate carboxylase (Rubisco) content declined as senescence progressed. Endopeptidase activity with Rubisco as a physiological substrate exhibited significant increase at acidic (pH 4.8) than at neutral (pH 7.0) during drought induced senescence and declined during recovery. Natural senescence was associated with a several-fold increase in the endopeptidase activity at both the pHs. Cysteine proteases were analyzed using western blot with polyclonal antibodies raised against papain. Several polypeptides of molecular weights 57, 52, and 43 kDA were recognized by the antibodies, the levels of which showed an increase under water deficit conditions, followed by a decrease during recovery. Three polypeptides of molecular weights 69, 60, and 48 kDa appeared only during the water stress conditions, whereas, during natural senescence, only a single 48 kDa polypeptide with maximum intensity at 9 days after flowering was observed. The results suggests the possibility of distinguishing drought-induced and natural senescence.     

Wheat cultivars differing in heat tolerance show a differential response to monocarpic senescence under high-temperature stress and the involvement of serine proteases

High temperature is a common constraint during anthesis and grain-filling stages of wheat leading to huge losses in yield. In order to understand the mechanism of heat tolerance during monocarpic senescence, the present study was carried out under field conditions by allowing two well characterized Triticum aestivum L. cultivars differing in heat tolerance, Hindi62 (heat-tolerant) and PBW343 (heat-susceptible), to suffer maximum heat stress under late sown conditions. Senescence was characterized by measuring photosynthesis related processes and endoproteolytic activity during non-stress environment (NSE) as well as heat-stress environment (HSE). There was a faster rate of senescence under HSE in both the genotypes. Hindi62, having pale yellow flag leaf with larger area, maintained cooler canopy under high temperatures than PBW343. The tolerance for high temperature in Hindi62 was clearly evident in terms of slower green-leaf area degradation, higher stomatal conductance, higher stability in maximum PSII efficiency, Rubisco activity and Rubisco content than PBW343. Both the genotypes exhibited lower endopeptidase activity under HSE as compared to NSE and this difference was more apparent in Hindi62. Serine proteases are the predominant proteases responsible for protein degradation under NSE as well as HSE. Flag leaf of both the genotypes exhibited high-molecular-mass endoproteases (78 kDa and 67 kDa) isoforms up to full grain maturity which were inhibited by specific serine protease inhibitor in both the environments. In conclusion, the heat-tolerant Hindi62 exhibited a slower rate of senescence than the heat-susceptible PBW343 during HSE, which may contribute towards heat stability.     

Dyschromatosis universalis hereditaria: Infrequent genodermatoses in India

Dyschromatosis universalis hereditaria (DUH) is a rare genodermatosis reported initially and mainly in Japan. However, subsequent cases have been reported from other countries. We report a case of DUH in a south Indian woman with a positive family history with cosmetic disfigurement and severe psychological impairment.     

Neutralizing and protective human monoclonal antibodies recognizing the N-terminal domain of the SARS-CoV-2 spike protein

1. Download : Download high-res image (164KB)
2. Download : Download full-size image

     

Dysregulated expression of microRNAs in aqueous humor from intraocular tuberculosis patients

Molecular Biology Reports - Systemic Mycobacterium tuberculosis (Mtb) infection alters microRNA’s expression that controls cellular processes and modulates host defense mechanisms. However,...     

CXCR4 or CXCR7 antagonists treat endometriosis by reducing bone marrow cell trafficking

Adult stem cells have a major role in endometrial physiology, including remodelling and repair. However, they also have a critical role in the development and progression of endometriosis. Bone marrow‐derived stem cells engraft eutopic endometrium and endometriotic lesions, differentiating to both stromal and epithelial cell fates. Using a mouse bone marrow transplantation model, we show that bone marrow‐derived cells engrafting endometriosis express CXCR4 and CXCR7. Targeting either receptor by the administration of small molecule receptor antagonists AMD3100 or CCX771, respectively, reduced BM‐derived stem cell recruitment into endometriosis implants. Endometriosis lesion size was decreased compared to vehicle controls after treatment with each antagonist in both an early growth and established lesion treatment model. Endometriosis lesion size was not effected when the local effects of CXCL12 were abrogated using uterine‐specific CXCL12 null mice, suggesting an effect primarily on bone marrow cell migration rather than a direct endometrial effect. Antagonist treatment also decreased hallmarks of endometriosis physiopathology such as pro‐inflammatory cytokine production and vascularization. CXCR4 and CXCR7 antagonists are potential novel, non‐hormonal therapies for endometriosis.     

Crystal Structure and Functional Analysis of JMJD5 Indicate an Alternate Specificity and Function

JMJD5 is a Jumonji C (JmjC) protein that has been implicated in breast cancer tumorigenesis, circadian rhythm regulation, embryological development, and osteoclastogenesis. Recently, JMJD5 (also called KDM8) has been reported to demethylate dimethylated Lys-36 in histone H3 (H3K36me2), regulating genes that control cell cycle progression. Here, we report high-resolution crystal structures of the human JMJD5 catalytic domain in complex with the substrate 2-oxoglutarate (2-OG) and the inhibitor N-oxalylglycine (NOG). The structures reveal a β-barrel fold that is conserved in the JmjC family and a long shallow cleft that opens into the enzyme's active site. A comparison with other JmjC enzymes illustrates that JMJD5 shares sequence and structural homology with the asparaginyl and histidinyl hydroxylase FIH-1 (factor inhibiting hypoxia-inducible factor 1 [HIF-1]), the lysyl hydroxylase JMJD6, and the RNA hydroxylase TYW5 but displays limited homology to JmjC lysine demethylases (KDMs). Contrary to previous findings, biochemical assays indicate that JMJD5 does not display demethylase activity toward methylated H3K36 nor toward the other methyllysines in the N-terminal tails of histones H3 and H4. Together, these results imply that JMJD5 participates in roles independent of histone demethylation and may function as a protein hydroxylase given its structural homology with FIH-1 and JMJD6.