The N-glycan processing enzymes α-mannosidase and β-D-N-acetylhexosaminidase are involved in ripening-associated softening in the non-climacteric fruits of capsicum

Excessive softening of fruits during the ripening process leads to deterioration. This is of significant global importance as softening-mediated deterioration leads to huge postharvest losses. N-glycan processing enzymes are reported to play an important role during climacteric fruit softening: however, to date these enzymes have not been characterized in non-climacteric fruit. Two ripening-specific N-glycan processing enzymes, α-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex), have been identified and targeted to enhance the shelf life in non-climacteric fruits such as capsicum (Capsicum annuum). The purification, cloning, and functional characterization of α-Man and β-Hex from capsicum, which belong to glycosyl hydrolase (GH) families 38 and 20, respectively, are described here. α-Man and β-Hex are cell wall glycoproteins that are able to cleave terminal α-mannose and β-D-N-acetylglucosamine residues of N-glycans, respectively. α-Man and β-Hex transcripts as well as enzyme activity increase with the ripening and/or softening of capsicum. The function of α-Man and β-Hex in capsicum softening is investigated through RNA interference (RNAi) in fruits. α-Man and β-Hex RNAi fruits were approximately two times firmer compared with the control and fruit deterioration was delayed by approximately 7 d. It is shown that silencing of α-Man and β-Hex enhances fruit shelf life due to the reduced degradation of N-glycoproteins which resulted in delayed softening. Altogether, the results provide evidence for the involvement of N-glycan processing in non-climacteric fruit softening. In conclusion, genetic engineering of N-glycan processing can be a common strategy in both climacteric and non-climacteric species to reduce the post-harvest crop losses

Modification of cesium toxicity by calcium in mammalian system

The interaction between cesium chloride CsCl and calcium chloride CaCl2 was observed in bone marrow chromosomes of mice. The two salts were administered orally to laboratory bred Swiss albino mice in vivo singly or one followed by the other, or both simultaneously. CsCl induced chromosomal aberrations in frequencies directly proportional to the dose administered. The frequency of aberrations was reduced significantly when the two chemicals were administered simultaneously or when CaCl2 was given 2 h before CsCl. Thus, CaCl2 is able to protect against the cytotoxicity of CsCl

On Application of Constitutional Descriptors for Merging of Quinoxaline Data Sets Using Linear Statistical Methods

The present paper is an attempt for unifying two different quinoxaline data sets with a wide range of substituents in 2, 3, 7, and 8 positions having excellent antitubercular activities with a view to developing robust and reliable structure–activity relationships. The merging has been performed for these two sets of quinoxaline 1,4-di-N-oxides derivatives comprising 29 and 18 compounds, respectively, on the basis of constitutional descriptors, which denotes the structural characterization of the molecules. Principal component analysis was performed to see the distribution of the compounds from two data sets for the constitutional descriptors. The distribution of compounds in score plot based on constitutional descriptors suggests unification of quinoxaline data sets which is useful for the model development. Outlier detection was performed from the standpoint of residual analysis of the partial least squares regression models. The superiority of the constitutional descriptors over other calculated molecular descriptors has been established from the standpoint of leave-one-out cross-validation technique associated with partial least squares regression analysis. Internal validation through the leave-many-out methodology was also performed with good results, assuring the stability of the models. The results obtained from linear partial least squares regression analysis lead to a statistically significant and robust quantitative structure–activity relationship modeling

Comparative efficacy of chlorophyllin in reducing cytotoxicity of some heavy metals

The potential of chlorophyllin in reducing clastogenicity was studied against two concentrations of each of three potent metallic clastogens (cesium chloride, mercuric chloride and cobalt chloride) in bone marrow cells of mice in vivo. The respective salts and chlorophyllin were administered orally to mice by gavaging in different combinations. Simultaneous administration of chlorophyllin with both concentrations of each salt reduced the clastogenic effects in the order Cs>Hg >Co. Chlorophyllin could not decrease the clastogenic effects when administered 2 h before the salts

Insights into transcriptional regulation of β-D-N-acetylhexosaminidase, an N-glycan-processing enzyme involved in ripening-associated fruit softening

Tomato (Solanum lycopersicum) fruit ripening-specific N-glycan processing enzyme, β-D-N-acetylhexosaminidase (β-Hex), plays an important role in the ripening-associated fruit-softening process. However, the regulation of fruit ripening-specific expression of β-Hex is not well understood. We have identified and functionally characterized the fruit ripening-specific promoter of β-Hex and provided insights into its transcriptional regulation during fruit ripening. Our results demonstrate that RIPENING INHIBITOR (RIN), a global fruit ripening regulator, and ABSCISIC ACID STRESS RIPENING 1 (SlASR1), a poorly characterized ripening-related protein, are the transcriptional regulators of β-Hex. Both RIN and SlASR1 directly bound to the β-Hex promoter fragments containing CArG and C_2-3(C/G)A cis-acting elements, the binding sites for RIN and SlASR1, respectively. Moreover, β-Hex expression/promoter activity in tomato fruits was downregulated once expression of either RIN or SlASR1 was suppressed; indicating that RIN and SlASR1 positively regulate the transcription of β-Hex during fruit ripening. Interestingly, RIN could also bind to the SlASR1 promoter, which contains several CArG cis-acting elements, and SlASR1 expression was suppressed in rin mutant fruits, indicating that RIN also acts as a positive regulator of SlASR1 expression during fruit ripening. Taken together, these results suggest that RIN, both directly and indirectly, through SlASR1, regulates the transcription of β-Hex during fruit ripening. The fruit ripening-specific promoter of β-Hex could be a useful tool in regulating gene expression during fruit ripening

ESTIMATION OF PREVALENCE OF HEPATITIS C VIRUS INFECTION BY SEROLOGICAL TEST AND REAL TIME RT-PCR TEST AMONG SUSPECTED VIRAL HEPATITIS CASES ATTENDING TERTIARY CARE HOSPITAL, KOLKATA : PREVALENCE OF HEPATITIS C VIRUS INFECTION BY SEROLOGICAL TEST AND REAL TIME RT-PCR TEST

Objective: Hepatitis C virus(HCV) infection is a major public health problem in India and worldwide. Majority remain asymptomatic until they develop serious complications like liver cirrhosis or hepatocellular carcinoma with fatal outcome. Hence early diagnosis of active HCV infection and prompt initiation of treatment is important. Treatment with directly acting antivirals(DAAs) resulted in high sustained virological response(SVR) rates of >95% globally. This study was done to estimate sero-prevalence and prevalence of active HCV infection among study population. After initiation of treatment, SVR rates were estimated. Methods: This was hospital based cross-sectional observational study. Screening was done by 3rd-generation ELISA to detect anti-HCV antibody, then confirmatory real time RT-PCR test was done for detection of active cases and determining their viral load. Treatment of 12 weeks duration was initiated by DAAs and followed up to estimate SVR by doing real time RT-PCR after 12 weeks of treatment completion. Result: Among 17,752 consecutive non-repetitive blood samples, seroprevalence was 1.78%. Prevalence of active cases was1.52%. HCV active infection was prevalent more among male(64.21%) and among 40-60 years age group. History of multiple blood transfusion(58%) was most common risk factor, followed by multiple sex partners(13.3%). Coinfections with HBV and HIV was seen in 13.65% cases. 92% patients completed their treatment. SVR was 97.87%. Conclusion: High SVR of 97.87%, is evidence-based data that supports that proper treatment can eliminate HCV infection. Detection by real time RT-PCR and highly effective DAA has made a paradigm shift to approach of HCV diagnosis and management in recent times

Induction of Senescence and Identification of Differentially Expressed Genes in Tomato in Response to Monoterpene

<div><p>Monoterpenes, which are among the major components of plant essential oils, are known for their ecological roles as well for pharmaceutical properties. Geraniol, an acyclic monoterpene induces cell cycle arrest and apoptosis/senescence in various cancer cells and plants; however, the genes involved in the process and the underlying molecular mechanisms are not well understood. In this study, we demonstrate that treatment of tomato plants with geraniol results in induction of senescence due to a substantial alteration in transcriptome. We have identified several geraniol-responsive protein encoding genes in tomato using suppression subtractive hybridization (SSH) approach. These genes comprise of various components of signal transduction, cellular metabolism, reactive oxygen species (ROS), ethylene signalling, apoptosis and DNA damage response. Upregulation of NADPH oxidase and antioxidant genes, and increase in ROS level after geraniol treatment point towards the involvement of ROS in geraniol-mediated senescence. The delayed onset of seedling death and induced expression of geraniol-responsive genes in geraniol-treated ethylene receptor mutant (<i>Nr</i>) suggest that geraniol-mediated senescence involves both ethylene dependent and independent pathways. Moreover, expression analysis during tomato ripening revealed that geraniol-responsive genes are also associated with the natural organ senescence process.</p></div

Expression profiles of geraniol-responsive transcripts.

<p>Tomato seedlings were treated with 10-PCR analysis was carried out for 50 genes selected from SSH library. Data are mean (n = 3). Tomato actin was used as endogenous control.</p

Up-regulation of geraniol-responsive genes at the onset of fruit senescence.

<p>(A) Tomato fruits used in this study: mature green (MG), breaker (BR), pink (P) and red ripe (RR). (B) Transcript level of 25 geraniol-responsive genes was determined in different ripening stages of fruits by qRT-PCR analysis. Tomato actin was used as endogenous control. Data are mean (n = 3).</p

Phytotoxic effect of geraniol on tomato seedlings.

<p>Seedlings were fed with MS medium containing 50 µM to 10 mM geraniol, 20% DMSO and 100 mM ethanol. Seedlings treated with geraniol showed rapid loss of vigor and viability.</p