Effects of Zn2+ and Cu2+ on growth,lignin degradation and ligninolytic enzymes in Phanerochaete chrysosporium

The influence of Zn²⁺ (6.0 × 10^–3 –18.0 × 10^–3 M) and Cu²⁺ (4 × 10^–4 –1.2 × 10^–4 M) in the basal medium on mycelial growth (dry weight), activities of lignin peroxidase (Lip), manganese peroxidase (Mnp), solubilization, and mineralization (¹⁴CO₂ evolution) of lignin during a period of 3 weeks was studied in Phanerochaete chrysosporium strain MTCC-787. Highest mycelial growth was obtained at 0.6 M Zn²⁺ and 0.4 M Cu²⁺ levels. Enzyme activities were found to increase up to the highest levels of both the trace elements. However, Zn²⁺ had a relatively more stimulatory effect on Lip production and the reverse was true in case of Cu²⁺. [¹⁴C]Lignin solubilization was also promoted by higher levels of both trace elements. Mineralization of [¹⁴C]lignin was optimal at 6.0 M Zn²⁺ and 1.2 M Cu²⁺. The stimulatory effect of Zn²⁺ on Lip production was correlated with higher rates of [¹⁴C]lignin mineralization.     

Crossability of Brassica tournefortii and B. rapa, and morphology and cytology of their F1 hybrids

The crossability between Brassica tournefortii (TT, 2n = 20) and Brassica rapa (AA, 2n = 20) and the cytomorphology of their F₁ hybrids were studied. Hybrids between these two species were obtained only when B. tournefortii was involved as a female parent. The hybrid plants were intermediate for most of the morphological attributes and were found to be free from white rust under field conditions. The F₁ plants showed poor pollen fertility, although occasional seed set was achieved from open pollination. Self-pollination or backcrosses did not yield any seeds in these plants. The occurrence of chromosome association ranging from bivalents (0–7), trivalents (0–2) to a rare quadrivalent (0–1) in the dihaploid hybrids indicates pairing between the T and A genomes. The homoeologous pairing coupled with seed set in the F₁ plants offer an opportunity for interspecific gene transfers from B. tournefortii to B. rapa and vice-versa through interspecific hybridization. Received: 3 July 2000 / Accepted: 22 September 2000     

Comparative evaluation of hydro-, chemo- , and hormonal-priming methods for imparting salt and PEG stress tolerance in Indian mustard (<Emphasis Type="Italic">Brassica</Emphasis><Emphasis Type="Italic">juncea</Emphasis> L.)

The present study was aimed to evaluate the effect of different seed priming methods to enhance the sodium chloride (NaCl) and polyethylene glycol-8000 (PEG-8000) stress tolerance in Indian mustard (Brassica juncea L.). Seeds subjected to different priming treatments such as water (hydro-priming), calcium chloride (CaCl₂) (chemo-priming), and abscisic acid (ABA) (hormonal-priming) showed increased rate of germination as compared to non-primed seeds. The primed and non-primed seeds were grown for 15 days and then the seedlings were independently subjected to iso-osmotic salt (150 mM NaCl) or PEG-8000 (20%) stress. The different biochemical responses were studied 10 days after treatment. Under NaCl and PEG stress, the dry weight and total chlorophyll content were higher in primed sets as compared to non-primed treatment which was also evident by the phenotype of the seedlings. In general, the higher activities of superoxide dismutase and glutathione reductase resulted in lower oxidative damage, in terms of malondialdehyde content, under NaCl and PEG stress in hydro-primed set as compared to non-primed, ABA-, and CaCl₂-primed treatments. Besides, the level of total phenolics and accumulation of osmolytes such as free proline, glycine betaine, and total soluble sugars was also lower in hydro-primed set as compared to other primed and non-primed treatments. The study thus suggests the use of hydro-priming as a simple and cost-effective strategy to alleviate the NaCl and PEG induced stress in B. juncea.     

New natural cholinesterase inhibiting and calcium channel blocking quinoline alkaloids

During this study, one new coumarin; 7-O-beta-D-glucopyranoside-2H-1-benzopyran-2-one (1) and three quinoline alkaloids; 3-hydroxy, 2, 2, 6-trimethyl-3, 4, 5, 6-tetrahydro-2H-pyrano[3,2-c] quinoline 5-one (2), ribalinine (3) and methyl isoplatydesmine (4) were isolated from the aerial parts of Skimmia laureola and their structures established by spectroscopic studies. Compounds 2-4 were found to be linear mixed type inhibitors of acetylcholinesterase (K(i) = 110.0, 30.0 and 30.0 microM, respectively). Compounds 2 and 3 were also found to be linear mixed type inhibitors of butyrylcholinesterase, while compound 4 was a noncompetitive inhibitor of the enzyme (K(i) = 90.0, 70.0 and 19.0 microM, respectively). The inhibition of acetyl- and butyryl-cholinesterase enzymes persists as the most promising therapeutic strategy for activating the impaired cholinergic functions in Alzheimer's disease and related dementias. Compound 4 also showed dose-dependent spasmolytic activity in the isolated rabbit jejunum intestinal preparation by relaxing the spontaneous (EC50 = 0.1 mg/mL) and K(+)-induced contractions (EC50 = 0.4 mg/mL), suggesting that the spasmolytic effect of compound 4 is mediated through the blockade of voltage-dependent Ca2+ channels.     

Oligomeric complexes formed by Redβ single strand annealing protein in its different DNA bound states

Redβ is a single strand annealing protein from bacteriophage λ that binds loosely to ssDNA, not at all to pre-formed dsDNA, but tightly to a duplex intermediate of annealing. As viewed by electron microscopy, Redβ forms oligomeric rings on ssDNA substrate, and helical filaments on the annealed duplex intermediate. However, it is not clear if these are the functional forms of the protein in vivo. We have used size-exclusion chromatography coupled with multi-angle light scattering, analytical ultracentrifugation and native mass spectrometry (nMS) to characterize the size of the oligomers formed by Redβ in its different DNA-bound states. The nMS data, which resolve species with the highest resolution, reveal that Redβ forms an oligomer of 12 subunits in the absence of DNA, complexes ranging from 4 to 14 subunits on 38-mer ssDNA, and a much more distinct and stable complex of 11 subunits on 38-mer annealed duplex. We also measure the concentration of Redβ in cells active for recombination and find it to range from 7 to 27 μM. Collectively, these data provide new insights into the dynamic nature of the complex on ssDNA, and the more stable and defined complex on annealed duplex.     

Effects of salt stress in relation to osmotic adjustment on sugarcane (<Emphasis Type="Italic">Saccharum officinarum</Emphasis> L.) callus cultures

In vitro responses of embryogenic sugarcane (Saccharum officinarum L.; cv. CoC-671) calli stressed with different levels of NaCl (0.0, 42.8, 85.6, 128.3, 171.1, 213.9 or 256.7 mM) were studied. The results showed that a significant decrease in callus growth and cell viability occurred with ≥85.6 mM NaCl. Higher amounts of free proline and glycine betaine were accumulated in NaCl-stressed calli. Although the leached and retained Na⁺ contents increased, the retained K⁺ content decreased with increasing levels of NaCl. Such a mechanism implies that sugarcane can be considered as a Na⁺-excluder. The accumulation of salt ions and osmolytes could play an important role in osmotic adjustment in sugarcane cells under salt stress.     

All-trans retinoic acid prevents development of cardiac remodeling in aortic banded rats by inhibiting the renin-angiotensin system

This study was designed to determine the effect of all-trans retinoic acid (RA) on the development of cardiac remodeling in a pressure overload rat model. Male Sprague-Dawley rats were subjected to sham operation and the aortic constriction procedure. A subgroup of sham control and aortic constricted rats were treated with RA for 5 mo after surgery. Pressure-overloaded rats showed significantly increased interstitial and perivascular fibrosis, heart weight-to-body weight ratio, and gene expression of atrial natriuretic peptide and brain natriuretic peptide. Echocardiographic analysis showed that pressure overload induced systolic and diastolic dysfunction, as evidenced by decreased fractional shortening, ejection fraction, stroke volume, and increased E-to-E(a) ratio and isovolumic relaxation time. RA treatment prevented the above changes in cardiac structure and function and hypertrophic gene expression in pressure-overloaded rats. RA restored the ratio of Bcl-2 to Bax, inhibited cleavage of caspase-3 and -9, and prevented the decreases in the levels of SOD-1 and SOD-2. Pressure overload-induced phosphorylation of ERK1/2, JNK, and p38 was inhibited by RA, via upregulation of mitogen-activated protein kinase phosphatase (MKP)-1 and MKP-2. The pressure overload-induced production of angiotensin II was inhibited by RA via upregulation of expression of angiotensin-converting enzyme (ACE)2 and through inhibition of the expression of cardiac and renal renin, angiotensinogen, ACE, and angiotensin type 1 receptor. Similar results were observed in cultured neonatal cardiomyocytes in response to static stretch. These results demonstrate that RA has a significant inhibitory effect on pressure overload-induced cardiac remodeling, through inhibition of the expression of renin-angiotensin system components.     

Phytochemicals from the stem wood of Sorbus lanata (D. Don.) Schauer

Three new phenolic compounds, sorlanin (4-(3-(hydroxymethyl)-5-methoxy-7-phenyl-2,3-dihydrobenzo[b][1,4]dioxin-2-yl)-2-methoxyphenol, 1), sorbanin (2-((3,5-dimethoxy-[1,1′-biphenyl]-4-yl)oxy)-1-(4-hydroxy-3-methoxyphenyl)propane-1,3-diol, 2) and sorbalanin (4-(3-(hydroxymethyl)-5,6-dimethoxy-2,3-dihydrobenzo[b][1,4]dioxino[2,3-g]benzofuran-2-yl)-2-methoxyphenol, 3), together with eight known compounds, polystachyol (4), isolariciresinol (5), dihydrodehydrodiconiferyl alcohol (6), tuberculatin (7), ovafolinin E (8), aucuparin (9), 2′-methoxyaucuparin (10), and tetracosyl-3-(3,4-dihydroxyphenyl)acrylate (11), were isolated from Sorbus lanata. The structures of these phytoconstituents were elucidated through extensive spectroscopic techniques, including UV, IR, 1D and 2D NMR, ESI-MS and HRESI-MS experiments. All the compounds except 9 and 10 were isolated for the first time from the genus Sorbus. The isolated compounds were also tested in DPPH radical scavenging reaction where compounds 6, 7, 10 and 11 showed significant activities with IC₅₀ values of 9.2, 11.7, 23.0 and 33.7 μM, respectively.     

Expression of Putative Stem Cell Marker,Hepatocyte Nuclear Factor 4 Alpha,in Mammary Gland of Water Buffalo

Buffaloes account for more than 56% of total milk production in India. Cyclic remodeling of mammary glands of human, mice, cow, sheep, and goat is determined by mammary stem cells. It is logical to assume that buffalo mammary gland will have mammary stem/progenitor cells. Thus far, no report exists on identification of buffalo mammary stem cells. Hepatocyte nuclear factor 4 alpha (HNF4A) is a candidate marker for hepatic progenitor cells and has recently been suggested as a marker of bovine mammary stem/progenitor cells. We hypothesized that (1 Pasha TN, Hayat Z. Present situation and future perspective of buffalo production in Asia. J Anim Plant Sci 2012; 22(3 supple.):250–256. [Google Scholar]) HNF4A identifies putative buffalo mammary stem/progenitor cells and (2 NDDB. National Dairy Development Board. 2015. http://www.nddb.org/English/Statistics/Pages/Milk-Production.aspx. Accessed May 10, 2015. [Google Scholar]) the number of HNF4A-positive cells increases during mastitis. Sixteen buffalo mammary samples were collected from a local slaughterhouse. Hematoxylin and eosin staining were performed on 5-micron thick sections and on the basis of gross examination and histomorphology of the mammary glands, physiological stages of the animals were estimated as non-lactating (n = 4), mastitis (n = 9), and prepubertal (n = 3). In total, 24048 cells were counted (5–10 microscopic fields/animal; n = 16 animals) of which, 40% cells were mammary epithelial cells (MEC) and 60% cells were the stromal cells. The percentage of MEC in non-lactating animals was higher compared to mastitic animals (47.3% vs. 37.3%), which was likely due to loss of MEC in mastitis. HNF4A staining was observed in nuclei of MEC of ducts, alveoli, and stromal cells. Basal location and low frequency of HNF4A-positive MEC (ranges from 0.4–4.5%) were consistent with stem cell characteristics. Preliminary study showed coexpression of HNF4A with MSI1 (a mammary stem cell marker in sheep), suggesting HNF4A was likely to be a putative mammary stem/progenitor cell marker in buffalo. HNF4A-positive MEC (basal and luminal; light and dark stained) tended to be higher in non-lactating than the mastitic animals (8.73 ± 1.71% vs. 4.29 ± 1.19%; P = 0.07). The first hypothesis that HNF4A identify putative mammary stem/progenitor cells was confirmed but the second hypothesis that the number of mammary stem/progenitor cells decreases during mastitis was unsupported. This is the first report outlining the expression of HNF4A and identification of putative mammary stem/progenitor cells in buffalo mammary gland.