Mentha piperita (Linn) leaf extract provides protection against radiation induced alterations in intestinal mucosa of Swiss albino mice

Intestinal protection in mice against radiation injury by M. piperita (1 g/kg body weight/day) was studied from day 1 to day 20 after whole body gamma irradiation (8 Gy). Villus height, goblet cells/villus section, total cells, mitotic cells and dead cells/crypt section in the jejunum are good parameters for the assessment of radiation damage. There was significant decrease in the villus height, number of total cells and mitotic cells/crypt section, whereas goblet cells and dead cells showed significant increase after irradiation. Mentha pretreatment resulted in a significant increase in villus height, total cells and mitotic cells, whereas goblet cells and dead cells showed a significant decrease from respective irradiated controls at each autopsy day. The results suggest that Mentha pretreatment provides protection against radiation induced alterations in intestinal mucosa of Swiss albino mice.     

Amylase hyperproduction by deregulated mutants of the thermophilic fungus Thermomyces lanuginosus

Thermomyces lanuginosus was subjected to three cycles of mutagenesis (UV/NTG) and a selection procedure to develop amylase-hyperproducing, catabolite-repression-resistant and partially constitutive strains. One of the selected derepressed mutant strain III₅₁, produced ∼7- and 3-fold higher specific activity of α-amylase (190 U/mg protein) and glucoamylase (105 U/mg protein), respectively, compared to a wild-type parental strain. Further, the effect of production parameters on mutant strain III₅₁ was studied using a Box–Behnken design. The regression models computed showed significantly high R ² values of 96 and 97% for α-amylase and glucoamylase activities, respectively, indicating that they are appropriate for predicting relationships between corn flour, soybean meal and pH with α-amylase and glucoamylase production. Journal of Industrial Microbiology & Biotechnology (2002) 29, 70–74 doi:10.1038/sj.jim.7000270 Received 05 July 2001/ Accepted in revised form 16 April 2002     

Fatty acids compositions of polar and non-polar lipid fractions of wheat leaves inoculated with three brown rust races during progressive pathogenesis

The fatty acids composition of the polar and non-polar lipid fractions of wheat leaves was affected due to progressive brown rust infection during early stages of pathogenesis,i.e. 0, 12, 24, 36, 48 and 72 h after inoculation. The three races ofPuccinia recondita differentially affected the composition of saturated and unsaturated fatty acids and their relative occurrence in wheat leaves. The infection of wheat by race 77 resulted in a relative decrease in fatty acid chain length as measured through C₁₆∶C₁₈ fatty acid ratio. An increase in the relative degree of unsaturation (18∶2/18∶3 acids ratio) was recorded in both lipid fractions. Such changes may be taken as one of the earliest characteristics of disease development.     

Modification of intracellular calcium concentration in cardiomyocytes by inhibition of sarcolemmal Na+/H+ exchanger

Although the Na(+)/H(+) exchanger (NHE) is considered to be involved in regulation of intracellular Ca(2+) concentration ([Ca(2+)](i)) through the Na(+)/Ca(2+) exchanger, the exact mechanisms of its participation in Ca(2+) handling by cardiomyocytes are not fully understood. Isolated rat cardiomyocytes were treated with or without agents that are known to modify Ca(2+) movements in cardiomyocytes and exposed to an NHE inhibitor, 5-(N-methyl-N-isobutyl)amiloride (MIA). [Ca(2+)](i) in cardiomyocytes was measured spectrofluorometrically with fura 2-AM in the absence or presence of KCl, a depolarizing agent. MIA increased basal [Ca(2+)](i) and augmented the KCl-induced increase in [Ca(2+)](i) in a concentration-dependent manner. The MIA-induced increase in basal [Ca(2+)](i) was unaffected by extracellular Ca(2+), antagonists of the sarcolemmal (SL) L-type Ca(2+) channel, and inhibitors of the SL Na(+)/Ca(2+) exchanger, SL Ca(2+) pump ATPase and mitochondrial Ca(2+) uptake. However, the MIA-induced increase in basal [Ca(2+)](i) was attenuated by inhibitors of SL Na(+)-K(+)-ATPase and sarcoplasmic reticulum (SR) Ca(2+) transport. On the other hand, the MIA-mediated augmentation of the KCl response was dependent on extracellular Ca(2+) concentration and attenuated by agents that inhibit SL L-type Ca(2+) channels, the SL Na(+)/Ca(2+) exchanger, SL Na(+)-K(+)-ATPase, and SR Ca(2+) release channels and the SR Ca(2+) pump. However, the effect of MIA on the KCl-induced increase in [Ca(2+)](i) remained unaffected by treatment with inhibitors of SL Ca(2+) pump ATPase and mitochondrial Ca(2+) uptake. MIA and a decrease in extracellular pH lowered intracellular pH and increased basal [Ca(2+)](i), whereas a decrease in extracellular pH, in contrast to MIA, depressed the KCl-induced increase in [Ca(2+)](i) in cardiomyocytes. These results suggest that NHE may be involved in regulation of [Ca(2+)](i) and that MIA-induced increases in basal [Ca(2+)](i), as well as augmentation of the KCl-induced increase in [Ca(2+)](i), in cardiomyocytes are regulated differentially.     

Mechanism of action of aflatoxin B1 in Bacillus megaterium.

Bacillus megaterium cells from various growth phases were equally susceptible to the lethal effects of aflatoxin B1. Known surfactants (EDTA and Tween-80) accentuated the effects of aflatoxin B1. Viability and inulin uptake in aflatoxin B1-exposed cells decreased considerably. The effect was concentration dependent. A straight-line relationship observed in the death curve indicated a single target for aflatoxin B1 action in B. megaterium. Leakage of intracellular constituents in B. megaterium was also concentration dependent, and this can be related to the extent of cell membrane damage.     

Mechanisms of lysophosphatidic acid-induced increase in intracellular calcium in vascular smooth muscle cells

Although lysophosphatidic acid (LPA) is known to cause an increase in intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMCs), the mechanisms of [Ca2+]i mobilization by LPA are not fully understood. In the present study, the effect of LPA on [Ca2+]i mobilization in cultured A10 VSMCs was examined by Fura-2 fluorescence technique. The expression of LPA receptors was studied by immunostaining. LPA was observed to increase [Ca2+]i in a concentration-dependent manner; this increase was dependent on the concentration of extracellular Ca2+. Both sarcolemmal (SL) Na(+)-Ca2+ exchange inhibitors (amiloride, Ni2+ and KB-R7943) and Na(+)-H+ exchange inhibitor (MIA) as well as SL store-operated Ca2+ channel (SOC) antagonists (SK&F 96365, tyrphostin A9 and gadolinium), unlike SL Ca2+ channel antagonists (verapamil and diltiazem), inhibited the LPA-induced increase in [Ca2+]i. In addition, sarcoplasmic reticulum (SR) Ca2+ channel blocker (ryanodine), SR Ca2+ channel opener (caffeine), SR Ca2+ pump ATPase inhibitor (thapsigargin) and inositol 1,4,5-trisphosphate (InsP3) receptor antagonists (xestospongin and 2-aminoethoxydiphenyl borate) were found to inhibit the LPA-induced Ca2+ mobilization. Furthermore, phospholipase C (PLC) inhibitor (U 73122) and protein kinase C (PKC) activator (phorbol 12-myristate 13-acetate) attenuated the LPA-induced increase in [Ca2+]i. These results indicate that Ca2+ mobilization by LPA involves extracellular Ca2+ entry through SL Na(+)-Ca2+ exchanger, Na(+)-H+ exchanger and SL SOCs. In addition, ryanodine-sensitive and InsP(3)-sensitive intracellular Ca2+ pools may be associated with the LPA-induced increase in [Ca2+]i. Furthermore, the LPA-induced [Ca2+]i mobilization in VSMCs seems to be due to the activation of both PLC and PKC.     

Response surface methodology for lovastatin production by Aspergillus terreus GD13 strain

A wild type Aspergillus terreus GD13 strain, chosen after extensive screening, was optimized for lovastatin production using statistical Box-Behnken design of experiments. The interactive effect of four process parameters, i.e. lactose and soybean meal, inoculum size (spore concentration) and age of the spore culture, on the production of lovastatin was evaluated employing response surface methodology (RSM). The model highlighted the positive effect of soybean meal concentration and inoculum level for achieving maximal level of lovastatin (1342 mg/l). The optimal fermentation conditions improved the lovastatin titre by 7.0-folds when compared to the titres obtained under unoptimized conditions.     

Physical mapping of DNA markers linked to stem rust resistance gene <Emphasis Type="Italic">Sr47</Emphasis> in durum wheat

Key message

Markers linked to stem rust resistance gene Sr47 were physically mapped in three small Aegilops speltoides chromosomal bins. Five markers, including two PCR-based SNP markers, were validated for marker-assisted selection.

Abstract

In durum wheat (Triticum turgidum subsp. durum), the gene Sr47 derived from Aegilops speltoides conditions resistance to race TTKSK (Ug99) of the stem rust pathogen (Puccinia graminis f. sp. tritici). Sr47 is carried on small interstitial translocation chromosomes (Ti2BL-2SL-2BL·2BS) in which the Ae. speltoides chromosome 2S segments are divided into four bins in genetic stocks RWG35, RWG36, and RWG37. Our objective was to physically map molecular markers to bins and to determine if any of the molecular markers would be useful in marker-assisted selection (MAS). Durum cultivar Joppa was used as the recurrent parent to produce three BC₂F₂ populations. Each BC₂F₂ plant was genotyped with markers to detect the segment carrying Sr47, and stem rust testing of BC₂F₃ progeny with race TTKSK confirmed the genotyping. Forty-nine markers from published sources, four new SSR markers, and five new STARP (semi-thermal asymmetric reverse PCR) markers, were evaluated in BC₂F₂ populations for assignment of markers to bins. Sr47 was mapped to bin 3 along with 13 markers. No markers were assigned to bin 1; however, 7 and 13 markers were assigned to bins 2 and 4, respectively. Markers Xrwgs38a, Xmag1729, Xwmc41, Xtnac3119, Xrwgsnp1, and Xrwgsnp4 were found to be useful for MAS of Sr47. However, STARP markers Xrwgsnp1 and Xrwgsnp4 can be used in gel-free systems, and are the preferred markers for high-throughput MAS. The physical mapping data from this study will also be useful for pyramiding Sr47 with other Sr genes on chromosome 2B.

     

Assessment of Genetic Diversity Among Rice Genotypes with Differential Adaptations to Salinity Using Physio-morphological and Molecular Markers

Breeding for salt tolerance using traditional screening and selection methods have been limited by the complex and polygenic nature of salt tolerance trait. This study was designed to evaluate some of the premium Basmati rice varieties for salt tolerance and to characterize genetic diversity among the rice varieties with different adaptations to saline soils using microsatellite (SSR) and ISSR markers. Plants of nine rice varieties including salt tolerant, salt sensitive and traditional Basmati, were grown in hydroponics using Yoshida solution containing 0 (control, pH 5.0) and 30 mM NaCl (Electrical conductivity 4.8 d/S, pH 5.0) and assessed for salinity tolerance on 1–9 scale as per IRRI standard evaluation system using seedling growth parameters, visual salt injuries and Na-K ratio. Physio-morphological studies showed that traditional Basmati rice varieties (Basmati 370 and HBC19) were more sensitive than the salt sensitive control variety, MI-48. SSR as well as ISSR marker systems generated higher levels of polymorphism and could distinguish between all the 9 rice cultivars. A total of 299 (225 polymorphic) and 437 (430 polymorphic) bands were detected using 28 UBC ISSR primers and 100 welldistributed mapped SSR markers, respectively. ISSR and SSR marker data-sets showed moderate levels of positive correlation (Mantel test, r = 0.43). The ISSR and SSR marker data analyzed using clustering algorithms showed two distinct clusters separating the Basmati (Basmati 370, HBC19 and CSR-30) from other non-aromatic indica (IR36, Pokkali, CSR10 and MI-48) rice varieties indicating greater divergence between Basmati and non-aromatic indica rice genotypes. Marker analysis showed a close relationship among the two traditional (Basmati 370 and HBC19) and cross-bred (CSR30) Basmati rice varieties and greater diversity between the two salt-tolerant genotypes, Pokkali and BR4-10.