Enhancement of the chiroptical response of α-amino acids via N-substitution for molecular structure determination using vibrational circular dichroism

The chiroptical response in the form of vibrational circular dichroism (VCD) in the midinfrared region is found to be enhanced when a hydrogen of amino group of l -tryptophan is substituted with acetyl, acryloyl, or maleyl group. The order of preference for VCD enhancement is found to be acryloyl > acetyl > maleyl group. The resulting experimental VCD spectra are also found to be satisfactorily reproduced by the quantum mechanical (QM) predicted spectra. The QM predicted spectra were simulated using the conformer populations, (a) predicted by Gibbs energies and (b) optimized to maximize the similarity between experimental and predicted VCD spectra. It is found that the conformer populations predicted by Gibbs energies do not yield the maximum possible similarity between experimental and the QM predicted spectra. This work identifies the N-substitution of α-amino acids and determining the conformer populations that best reproduce the experimental spectra as two new approaches for molecular structure determination.     

Role of a metastatic suppressor gene KAI1/CD82 in the diagnosis and prognosis of breast cancer

Globally, breast cancer is the most common type of cancer in females and is one of the leading causes of cancer death in women. The advancement in the targeted therapies and the slight understanding of the molecular cascades of the disease have led to small improvement in the rate of survival of breast cancer patients. However, metastasis and resistance to the current drugs still remain as challenges in the management of breast cancer patients. Metastasis, potentially, leads to failure of the available treatment, and thereby, makes the research on metastatic suppressors a high priority. Tumor metastasis suppressors are several genes and their protein products that have the capability of arresting the metastatic process without affecting the tumor formation. The metastasis suppressors KAI1 (also known as CD82) has been found to inhibit tumor metastasis in various types of solid cancers, including breast cancer. KAI1 was identified as a metastasis suppressor that inhibits the process of metastasis by regulating several mechanisms, including cell motility and invasion, induction of cell senescence, cell–cell adhesion and apoptosis. KAI1 is a member of tetraspanin membrane protein family. It interacts with other tetraspanins, chemokines and integrins to control diverse signaling pathways, which are crucial for protein trafficking and intracellular communication. It follows that better understanding of the molecular events of such genes is needed to develop prognostic biomarkers, and to identify specific therapies for breast cancer patients. This review aims to discuss the role of KAI1/CD82 as a prognosticator in breast cancer.     

Calocalabaxanthone,the putative isoprenyl precursor of calabaxanthone from Calophyllum calaba

The bark of Calophyllum calaba var. calaba contains a new xanthone, 2,8-di-(3-methylbut-2-enyl)-1,3-dihydroxy-7-methoxyxanthone (calocalabaxanthone), the precursor of 5-hydroxy-8-methoxy-2,2-dimethyl-7-(3-methylbut-2-enyl)-2H,6H-pyano-(3,2-b)-xanthen-6-one (calabaxanthone). In addition the bark contains calabaxthone and the other constituents isolated earlier from Calophyllum calaba var. worthingtonii.     

Illegal and unmanaged aquaculture,unregulated fisheries and extreme climatic events combine to trigger invasions in a global biodiversity hotspot

Biological Invasions - Focusing on extreme climatic events in India’s Western Ghats Biodiversity Hotspot, we demonstrate that unmanaged aquaculture and unregulated fisheries can often combine...     

Synthesis and Biological Evaluation of Some Novel N-Alkyl/Aryl-1-Nitro-10H-Phenothiazine-3-Sulfonamide Derivatives

Russian Journal of Bioorganic Chemistry - A series of new derivatives of N-alkyl/aryl-1-nitro-10H-phenothiazine-3-sulfonamides were developed and synthesized by 1-nitro-10H-phenothiazine-3-sulfonyl...     

The pachytene chromosomes of Ipomoea crassicaulis

Summary The detailed morphology of the pachytene chromosomes and microsporogenesis have been studied in a diploid (2 n=30) American species, Ipomoea crassicaulis (Bth) B. L. Robinson. Idiogram of the pachytene chromosomes is presented and taking advantage of the extreme precision that pachytene analysis can lend, karyological characteristics of the haploid complement have been worked out in detail and individual chromosomes are identified. The course of meiosis was normal and over ninety five percent of pollen were found stainable. The urgent need for extending similar studies to other taxa in this economically important genus for unravelling phyletic relationships has been stressed.

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Zusammenfassung Bei der diploiden amerikanischen Ipomoea crassicaulis (Bth) B.L. Robinson (2 n=30) wird die Morphologie der Pachytänchromosomen und die Mikrosporogenese untersucht. Das Idiogramm der Pachytänchromosomen wird aufgestellt und unter Ausnutzung der großen Präzisionsmöglichkeit der Pachytänanalyse werden die charakteristischen Daten des haploiden Chromosomensatzes erarbeitet und alle Chromosomen identifiziert. Die Meiose verläuft normal und liefert zu mehr als 95% guten Pollen. Die Notwendigkeit umfassender ähnlicher Untersuchungen bei anderen taxonomischen Einheiten aus dieser wirtschaftlich wichtigen Gattung zwecks Klärung phylogenetischer Beziehungen wird nachdrücklich hervorgehoben.

     

Synthesis of glucosylceramide by purified calf spleen beta-glucosidase

Radioactive glucocerebroside was formed when purified calf spleen β-glucosidase was incubated in the presence of 4-methylumbelliferyl-β-$\text{D}$-glucoside and (¹⁴C) labeled ceramide. The product was identified by cochromatography on thin layer plates and carrier dilution and crystallization to constant specific activity. The radioactive glucocerebroside was also a substrate for hydrolysis by this same β-glucosidase preparation employed for its synthesis resulting in the liberation of labeled ceramide. Neither methyl-β-$\text{D}$-glucoside nor free D-glucose were effective in producing radioactive glucocerebroside when incubated with labeled ceramide in this system.