In vitro morphogenic response of different explants of Gentiana kurroo Royle from Western Himalayas—an endangered medicinal plant

Micropropagation offers a great potential to produce millions of clonal individuals through tissue culture via induction of morphogenesis. The aim of this work was to obtain an efficient protocol for callus regeneration for Gentiana kurroo Royle. The morphogenic response of different explants (leaves, petioles, roots) varied and responded differently for regeneration according to combinations of growth regulators. The petiole explants were best responding for callus induction and subsequently for indirect and direct regeneration. The callus induction was achieved on MS basal + 1.0 mg/l benzyladenine (BA) and 3.00 mg/l naphthalene acetic acid (NAA). MS medium supplemented with 0.10 mg/l NAA and 1.0 mg/l thidiazuron (TDZ) was recorded as the best medium for indirect regeneration. However, for direct regeneration the maximum number of shoot emergence was observed on MS basal fortified with 0.10 mg/l NAA + 0.75 mg/l TDZ. Half strength MS basal supplemented with indole-3-butyric acid (IBA) 1.00 mg/l gave best response for root induction. Subsequently, the plantlets were transferred and 100 % survival rate was recorded only on autoclaved cocopeat. No morphological variations were recorded in the callus regenerated plantlets.     

Yeast cytochrome c is a sequence-specific DNA-binding protein

A protein binding to the alcohol oxidase 2 upstream activation sequence (AOX2UAS) of the methylotropic yeast, Pichia pastoris, has been purified and identified as cytochrome c (cyt c). Cyt c purified from P. pastoris or Saccharomyces cerevisiae binds to AOX2UAS. Specific point mutations in AOX2UAS abolish cyt c binding. We conclude that yeast cyt c is a sequence-specific DNA-binding protein and may have a regulatory role in the nucleus.     

Pleomorphic lobular carcinoma of the breast. A case report

BACKGROUND: Pleomorphic lobular carcinoma of the breast is associated with aggressive behavior. CASE: Fine needle aspiration cytology was performed on a breast lump in a 55-year-old woman. The aspirates showed highly pleomorphic, large cells in a dyscohesive pattern, with a tendency of few cells to aggregate in small groups. A diagnosis of ductal carcinoma was made on cytology. On histology, the paraffin sections showed features of pleomorphic lobular carcinoma of the breast. CONCLUSION: The cytologic features of pleomorphic lobular carcinoma overlap with those of infiltrating ductal carcinoma. It is very difficult to make a diagnosis of pleomorphic lobular carcinoma prospectively on cytology. However, if Indian file arrangement and cytoplasmic vacuolation are present, pleomorphic lobular carcinoma must at least be suggested for the differential diagnosis as it has different clinical implications.     

How do plants defend themselves against pathogens-Biochemical mechanisms and genetic interventions

In agro-ecosystem, plant pathogens hamper food quality, crop yield, and global food security. Manipulation of naturally occurring defense mechanisms in host plants is an effective and sustainable approach for plant disease management. Various natural compounds, ranging from cell wall components to metabolic enzymes have been reported to protect plants from infection by pathogens and hence provide specific resistance to hosts against pathogens, termed as induced resistance. It involves various biochemical components, that play an important role in molecular and cellular signaling events occurring either before (elicitation) or after pathogen infection. The induction of reactive oxygen species, activation of defensive machinery of plants comprising of enzymatic and non-enzymatic antioxidative components, secondary metabolites, pathogenesis-related protein expression (e.g. chitinases and glucanases), phytoalexin production, modification in cell wall composition, melatonin production, carotenoids accumulation, and altered activity of polyamines are major induced changes in host plants during pathogen infection. Hence, the altered concentration of biochemical components in host plants restricts disease development. Such biochemical or metabolic markers can be harnessed for the development of “pathogen-proof” plants. Effective utilization of the key metabolites-based metabolic markers can pave the path for candidate gene identification. This present review discusses the valuable information for understanding the biochemical response mechanism of plants to cope with pathogens and genomics-metabolomics-based sustainable development of pathogen proof cultivars along with knowledge gaps and future perspectives to enhance sustainable agricultural production.     

Role of modified bleach method in staining of acid-fast bacilli in lymph node aspirates

OBJECTIVE: To correlate acid-fast bacilli (AFB) positivity with cytomorphologic patterns of tuberculous lymphadenitis and evaluate bleach concentration method in diagnosing lymph node tuberculosis compared to Ziehl-Neelsen (ZN) method. STUDY DESIGN: One hundred cases of tuberculous lymphadenitis diagnosed by fine needle aspiration cytology (FNAC) were analyzed and classified into 6 cytomorphologic patterns and correlated with bacillary load using routine and modified bleach methods of ZN staining. Smears were graded for AFB positivity. Sensitivity of routine ZN and modified bleach concentration was compared. RESULTS: The classic cytomorphologic pattern of tuberculosis showing epithelioid granulomas, Langerhans giant cells and caseous necrosis was seen in 23% of cases. Routine ZN staining detected AFB in 27% of cases and the modified bleach method in 72%. In 58 cases the modified bleach method had a higher grade of AFB positivity than the routine method. The modified bleach method did not miss any AFB positivity detected on routine ZN staining. CONCLUSION: The modified bleach method demonstrated AFB positivity in 72% of cases. AFB positivity grade was much higher than with routine ZN staining, making bacilli easily visible, with shorter screening time. The modified bleach method is inexpensive, easily performed and more sensitive and safe than routine ZN staining.     

一个1B/1R小麦-黑麦染色体易位的鉴定

本研究对冬小麦品系73(36)9-1的1B/1R易位染色体进行了遗传分析。发现73(36)9-1有一对随体染色体,它的两个亲本矮丰四号及洛夫林10(Lovrin lo)分别有两对和一对随体染色体。观察用矮丰四号回交的F_1,绝大部分花粉母细胞的中期染色体都能正常配对,而用洛夫林10回交的,除了多数产生两个单价体之外,正常配对的情况也能经常看到。同时还发现,73(36)9-1和“中国春”双端体(CSDT)的1BL能很好地配对并形成一个棒状的异形二价体,而它和CSDT 1BS的染色体则主要产生20″+1′+t′的构型,从而证明易位发生在1B染色体的短臂,并且该易位的片段来自黑麦染色体1RL。本文还讨论了该易位发生的可能途径,推断是由于在F_1花粉母细胞中的两个单价体(一个是小麦染色体1B,一个是黑麦染色体1R)同时进行错分裂之后产生的两种端着丝点染色体(1BL和1RL)重新并合形成的,因而冬小麦73(36)9-1可能是一个自发产生的易位系。     

Cytodiagnosis of eumycotic mycetoma: a case report

BACKGROUND: Mycetoma is a late-stage clinical manifestation of a subcutaneous infection produced by bacteria (actinomycetoma) or fungi (eumycetoma). Only a few articles have described the morphologic appearance of this uncommon pathology on cytology. The distinction between eumycetoma and actinomycetoma in fine needle aspiration cytology (FNAC) is as accurate as in histopathology, as demonstrated in the present case. CASE: A 30-year-old man presented with a large swelling on his left foot with a discharging sinus. FNAC of the swelling yielded pus-like material. Initial Papanicolaou and Giemsa stains showed the presence of septate, branching fungal hyphae and black granules against the inflammatory background. The presence of fungus was confirmed by PAS stain. The species was identified as Exophiala jeanselmei on fungal culture. CONCLUSION: Mycotic mycetoma can be accurately diagnosed by FNAC, which is a simple, inexpensive and rapid technique when there is a high index of suspicion. Special stains and culture studies are helpful in confirmation of diagnosis and species identification.     

Structural basis for feedforward control in the PINK1/Parkin pathway

PINK1 and parkin constitute a mitochondrial quality control system mutated in Parkinson’s disease. PINK1, a kinase, phosphorylates ubiquitin to recruit parkin, an E3 ubiquitin ligase, to mitochondria. PINK1 controls both parkin localization and activity through phosphorylation of both ubiquitin and the ubiquitin‐like (Ubl) domain of parkin. Here, we observed that phospho‐ubiquitin can bind to two distinct sites on parkin, a high‐affinity site on RING1 that controls parkin localization and a low‐affinity site on RING0 that releases parkin autoinhibition. Surprisingly, ubiquitin vinyl sulfone assays, ITC, and NMR titrations showed that the RING0 site has higher affinity for phospho‐ubiquitin than phosphorylated Ubl in trans. We observed parkin activation by micromolar concentrations of tetra‐phospho‐ubiquitin chains that mimic mitochondria bearing multiple phosphorylated ubiquitins. A chimeric form of parkin with the Ubl domain replaced by ubiquitin was readily activated by PINK1 phosphorylation. In all cases, mutation of the binding site on RING0 abolished parkin activation. The feedforward mechanism of parkin activation confers robustness and rapidity to the PINK1‐parkin pathway and likely represents an intermediate step in its evolutionary development.