Non-destructive insights into photosynthetic and photoprotective mechanisms in Arabidopsis thaliana grown under two light regimes

Probing insights into understanding photosynthetic processes via non-invasive means has an added advantage when used in phenotyping or precision agriculture. We employed Raman spectroscopy and fluorescence-based methods to investigate both the changes in the photosynthetic processes and the underlying protective mechanisms on Arabidopsis thaliana wild-type (WT), and ros1, which is a mutant of a repressor of transcriptional gene silencing, both grown under low light (LL: 100 μmol m^-2s^-1) and high light (HL: 400 μmol m^-2s^-1) regimes. Raman imaging detected a lower carotenoid intensity after two weeks in those plants grown under HL, compared to those grown under the LL regime; we interpret this as the result of oxidative damage of β-carotene molecules. Further, the data revealed a significant depletion in carotenoids with enhanced phenolics around the midrib and tip of the WT leaves, but not in the ros1. On the contrary, small necrotic zones appeared after two weeks of HL in the ros1 mutant, pointing to the starting oxidative damage. The lower maximum quantum yield of the photochemistry (F_v/F_m) in the WT as well as in the ros1 mutant grown in HL (compared to those in the LL two weeks post-exposure), indicates the HL partially inactivated photosystems. Chlorophyll a fluorescence imaging further showed high non-photochemical quenching (NPQ) in the plants grown under the HL regime for both the WT and the ros1 mutant, but the spatial heterogeneity of NPQ images was much higher in the HL-grown ros1 mutant. Fluorescence screening methods revealed significantly high values of chlorophyll proxies in the WT as well as in the ros1 mutant two weeks after in the HL compared to those under LL. The data generally revealed an increased accumulation of phenolics under HL in both the WT and ros1 mutant plants, but the proxies of anthocyanin and flavonols were significantly lower in the ros1 mutant than in the WT. The comparatively low accumulation of anthocyanin in the ros1 mutant compared to the WT supports the Raman data. We conclude that integrated use of these techniques can be efficiently applied for a better understanding of insights into photosynthetic mechanisms.

Synthesis of Polyene Bioactive Natural Products: FR252921 and Vitamin A

A formal synthesis of FR252921, a potent macrocyclic immunosuppressive agent, and a six-step synthesis of vitamin A have been demonstrated. The application of a ruthenium-catalyzed step-economic and environmentally benign strategy for the highly stereo- and chemoselective construction of valuable polyene motifs of FR252921 and vitamin A highlights the syntheses. The key features for the synthesis FR252921 include preparation of the triene moiety followed by two consecutive peptide couplings of the three fragments.

Cu-Catalyzed Click Reaction in Carbohydrate Chemistry

Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC), popularly known as the "click reaction", serves as the most potent and highly dependable tool for facile construction of simple to complex architectures at the molecular level. Click-knitted threads of two exclusively different molecular entities have created some really interesting structures for more than 15 years with a broad spectrum of applicability, including in the fascinating fields of synthetic chemistry, medicinal science, biochemistry, pharmacology, material science, and catalysis. The unique properties of the carbohydrate moiety and the advantages of highly chemo- and regioselective click chemistry, such as mild reaction conditions, efficient performance with a wide range of solvents, and compatibility with different functionalities, together produce miraculous neoglycoconjugates and neoglycopolymers with various synthetic, biological, and pharmaceutical applications. In this review we highlight the successful advancement of Cu(I)-catalyzed click chemistry in glycoscience and its applications as well as future scope in different streams of applied sciences.

First noscapine glycoconjugates inspired by click chemistry

The first click chemistry-inspired noscapine glycoconjugates have been developed in good to excellent yields to increase the therapeutic efficacy of noscapine.

Metal free synthesis of morpholine fused [5,1-c] triazolyl glycoconjugates via glycosyl azido alcohols

A series of diverse glycosyl 1,2-azido alcohols, obtained from readily available carbohydrates, were converted to structurally varied rare and novel sugar derived morpholine fused [5,1-c]-triazoles via a one-pot strategy.

Click chemistry inspired highly facile synthesis of triazolyl ethisterone glycoconjugates

Numerous deoxy-azido sugars 3 were prepared by the reaction of tosyl/bromo sugars with NaN3 in dry DMF under heating condition. The 1,3-dipolar cycloaddition of deoxy-azido sugars 3 with ethisterone 4 to afford regioselective triazole-linked ethisterone glycoconjugates 5 was investigated in the presence of CuI and DIPEA in dichloromethane or CuSO4·5H2O and sodium ascorbate in aqueous medium. All the developed compounds were characterized by spectroscopic analysis (IR, (1)H &(13)C NMR, and MS spectra). Structure of triazolyl ethisterone glycoconjugate 5a has been further confirmed by its Single Crystal X-ray analysis.

Idiopathic sclerosing encapsulating peritonitis--is a preoperative diagnosis possible? Report of three cases

Sclerosing encapsulating peritonitis (SEP) is a rare cause of intestinal obstruction that is usually diagnosed during a laparotomy; however, a preoperative diagnosis is possible. Sclerosing encapsulating peritonitis can be classified as primary or idiopathic and secondary types and only about 70 cases of idiopathic type have been reported since it was first described. It is characterized by a total or partial encasement of the small bowel by a thick fibrotic membrane. This report presents a series of three cases in which a diagnosis of idiopathic SEP was made preoperatively based on the clinical features and radiological findings, which were confirmed by a laparotomy and histopathology. All of the cases were successfully managed by the excision of the membrane. This report demonstrates that based on the clinical features and radiological investigations, in the absence of other plausible etiologies for intestinal obstruction, it is possible to suspect a preoperative diagnosis of SEP, thereby preventing a "surprise" finding during a laparotomy and allowing for better management.

DIAGNOSING DISSEMINATED INTRAVASCULAR COAGULATION IN ACUTE INFECTION : CAN WE DO WITHOUT FDP & D-DIMER

Alterations in coagulation profile viz. platelet count, prothrombin time (PT), partial thromboplastin time with kaolin (PTTK), thrombin time (TT) and fibrinogen were studied in 96 patients (73 males and 23 females) of acute infections. Fibrin/fibrinogen degradation products (FDP) level >25µg fibrinogen equivalent unit (FEU)/ml along-with D-dimer >1.0µg FEU/ml was considered criteria for diagnosis of disseminated intravascular coagulation (DIC). Normal values were established using plasma from 12 healthy voluntary blood donors. Out of these 96 patients, 15 had infection with Gram positive bacteria, 23 with Gram negative bacteria and 38 with Dengue. In 20 patients, nature of infection was not defined. Mean platelet count per cubic millimetre was 2.14 lac in Gram positive infection and 1.74 lac in Gram negative infection (p=0.07). There was no significant difference in other coagulation parameters in Gram positive and Gram negative infection. Platelet counts were low in 71% of Dengue patients but there was no significant alteration in PT, PTTK and TT. None of the Dengue patients had hypofibrinogenemia or DIC though hyperfibrinogenemia was present in 21% of Dengue patients. 20 patients had features of septicemia (Gram +ve 7, Gram -ve 8, undefined 5); 10 had concomitant DIC. DIC was present in additional 4 patients of acute infection without septicemia. PTTK was raised in 60% of the septicemia patients. 20 out of 82 non-DIC acute infection patients had subnormal PTTK. Commonest alteration in 14 DIC patients was raised PTTK with a sensitivity of 78.6% and specificity of 81.7%. Low fibrinogen levels though specific for DIC, were present in only 21.4% of the DIC patients. Combinations of PTTK >38 sec with PT >15 sec or platelet count < 1.5 lac/mmm(3) were good screening tests for DIC and detected 11 and 10 patients out of 14 with three and two false positives respectively.

IMMUNOBIOLOGICAL MONITORING OF VARIOUS GASTROINTESTINAL AND PRIMARY HEPATIC MALIGNANCIES

Carcinoembryonic antigen (CEA) and alpha fetoprotein levels (AFP) were assayed by enzyme-labelled immunoassay in 75 cases of gastrointestinal (GI) and primary hepatic malignancies. Mean CEA levels were found to be significantly higher (p<0.005) in metastatic non-operative group of GI malignancies (range 5.32 ng/mL to 175.2 ng/mL) as compared to early pre-operative cases (range 1.25 ng/mL to 33.2 ng/mL) and post-operative cases (range 1.41 ng/mL to 22.24 ng/mL). Variable levels of AFP were visualised in 12 cases of primary hepatic malignancies with eight cases having values less than 100 ng/mL. When both CEA and AFP were assayed simultaneously, the markers were helpful in differentiating cases of primary hepatic malignancies with low levels of CEA from 3 cases of secondaries in the liver where CEA levels were found to be highly raised (80.4 ng/mL to 146.4 ng/mL). To evaluate the variation of CEA and AFP levels in different patients having same stage of the disease, immunological monitoring for the functions of T and B cells was carried out by estimation of cytokine, i.e. interleukin-1 alpha (IL-1a), interleukin-2R (II-2R) and various immunoglobulins. IL-1a and 1L-2R levels were significantly higher (p<0.05) in the groups of patients having higher CEA and AFP. This indicates an important T cell (TH1 and TH2) function in the tumour antigen production.