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581.
Catalytic chromatography exploits both specific biological affinity and catalytic specificity to selectively purify enzymes. Two different applications are presented. Purification of EcoRI restriction endonuclease to apparent homogeneity was accomplished in a single step with significantly greater yield and purification than was obtained with affinity chromatography. An attempt to purify the multiple DNA polymerase activities of Escherichia coli was also developed. Five well-resolved peaks of DNA polymerase activity were fractionated. In this new chromatographic mode, the enzyme binds immobilized substrate coupled to a column in the absence of some required cofactor. When the missing cofactor is added, the enzyme converts substrate to product and selectively elutes from the column.  相似文献   
582.
Macrophage inducible nitric oxide synthase is able to generate massive amounts of nitric oxide (NO) which contributes to the host immune defense against viruses and bacteria. Monocyte-macrophages stimulated with the bacterial wall component lipopolysaccharide (LPS) and cytokines such as interferon-gamma (IFN-gamma) express the inducible form of nitric oxide synthase (iNOS). Furthermore, tumor necrosis factor-alpha (TNF-alpha) is one of the central regulatory cytokines in macrophage antimicrobial activity and synergizes with IFN-gamma in the induction of NO synthesis. Because of its pivotal role in both antimicrobial and tumoricidal activities of macrophages, a significant effort has focused on developing therapeutic agents that regulate NO production. In the present study fermented papaya preparation (FPP) is shown to exert both immunomodulatory and antioxidant activity in the macrophage cell line RAW 264.7. Interestingly, a low and a high molecular weight fraction (LMF and HMF, respectively) of FPP exhibited different activity patterns. FPP fractions alone did not affect NO production. However in the presence of IFN-gamma, both LMF and HMF significantly increased iNOS activity and nitrite as well as nitrate accumulation. NO radical formation measured in real-time by electron paramagnetic resonance spectroscopy was higher in the presence of LMF and IFN-gamma. On the contrary, iNOS mRNA levels were enhanced further with HMF than with LMF. Moreover, LMF displayed a stronger superoxide anion scavenging activity than HMF. In the presence of IFN-gamma, both FPP fractions stimulated TNF-alpha secretion. However in non-stimulated macrophages, TNF-alpha secretion was enhanced by HMF only. Since water-soluble FPP fractions contained no lipid A, present data indicate that FPP is a macrophage activator which augments nitric oxide synthesis and TNF-alpha secretion independently of lipopolysaccharides.  相似文献   
583.
584.
A cDNA library was constructed in lambda TriplEx2 vector using poly (A(+)) RNA from immature seeds of Cicer arietinum. The lectin gene was isolated from seeds of chickpea through library screening and RACE-PCR. The full-length cDNA of Chichpea seed lectin(CpGL)is 972 bp and contains a 807 bp open reading frame encoding a 268 amino acid protein. Analysis shows that CpSL gene has strong homology with other legume lectin genes. Phylogenetic analysis showed the existence of two main clusters and clearly indicated that CpSL belonged to mannose-specific family of lectins. RT-PCR revealed that CAA gene expressed constitutively in various plant tissues including flower, leaf, root and stem. When chickpea lectin mRNA level was checked in developing seeds, it was higher in 10 DAF seeds and decreased throughout seed development.  相似文献   
585.
Abstract  In zucchini, the use of row covers until flowering and the insect growth regulator (IGR) pyriproxyfen are effective methods of reducing the number of insects, especially silverleaf whitefly ( Bemisia tabaci (Gennadius) Biotype B), on plants. We compared floating row covers (FRCs) up until flowering with silverleaf whitefly (SLW) introduced (FRC + SLW), or not introduced (FRC-only), or with introduction of SLW in open plots (SLW-only), or with introduction of SLW in open plots with IGR (SLW + IGR). FRC increased temperature and humidity compared with the uncovered treatments. Average fruit weight was less ( P  < 0.01) for the FRC + SLW treatment compared with the other treatments and the percentage of marketable fruit was less for the FRC + SLW than for the other three treatments. This result indicates that the use of either row covers or IGR controls whiteflies, reduces fruit damage and increases the size, weight, and quality of fruit, and may also control other sap-sucking insects. However, if SLW are already present on plants, the use of FRC may reduce predation and favour build up of SLW. Thus, FRC and IGR, if used judiciously, may provide an effective alternative to broad-spectrum pesticides in small-scale cucurbit production.  相似文献   
586.

Key message

A new leaf rust resistance gene Lr79 has been mapped in the long arm of chromosome 3B and a linked marker was identified for marker-assisted selection.

Abstract

Aus26582, a durum wheat landrace from the A. E. Watkins Collection, showed seedling resistance against durum-specific and common wheat-specific Puccinia triticina (Pt) pathotypes. Genetic analysis using a recombinant inbred line (RIL) population developed from a cross between Aus26582 and the susceptible parent Bansi with Australian Pt pathotype showed digenic inheritance and the underlying loci were temporarily named LrAW2 and LrAW3. LrAW2 was located in chromosome 6BS and this study focused on characterisation of LrAW3 using RILs lacking LrAW2. LrAW3 was incorporated into the DArTseq map of Aus26582/Bansi and was located in chromosome 3BL. Markers linked with LrAW3 were developed from the chromosome survey sequence contig 3B_10474240 in which closely-linked DArTseq markers 1128708 and 3948563 were located. Although bulk segregant analysis (BSA) with the 90 K Infinium array identified 51 SNPs associated with LrAW3, only one SNP-derived KASP marker mapped close to the locus. Deletion bin mapping of LrAW3-linked markers located LrAW3 between bins 3BL11-0.85-0.90 and 3BL7-0.63. Since no other all stage leaf rust resistance gene is located in chromosome 3BL, LrAW3 represented a new locus and was designated Lr79. Marker sun786 mapped 1.8 cM distal to Lr79 and Aus26582 was null for this locus. However, the marker can be reliably scored as it also amplifies a monomorphic fragment that serves as an internal control to differentiate the null status of Aus26582 from reaction failure. This marker was validated among a set of durum and common wheat cultivars and was shown to be useful for marker-assisted selection of Lr79 at both ploidy levels.
  相似文献   
587.
Crabs belong to the superfamily Ocypodoidea are a significant component of benthic fauna and considered as ecosystem engineers because of their dynamic role as an active burrower in mangrove and estuarine environment. The current investigation was to evaluate the crab burrow density, diameter and total area of burrow opening along the coast of Pakistan. The variations in burrow properties and their relation to sediment characteristics were also evaluated to recognize the most influencing variables of sediments that effects on crab burrows. All crab burrow and sediment characteristics differed significantly (p < 0.05) among the monitoring sites. Regression analysis showed that crab density was significantly correlated with burrow density (P < 0.001). Moreover, burrow density was noticed significantly greater (p < 0.05) than crab density. Pearson correlation analysis reveals that moisture, porosity, organics, sand and mean grain size observed as most influencing the features of sediment to determine the ecological functioning of crab burrows in mangrove and mudflats of Pakistan.  相似文献   
588.
In these studies, liquid hot water (LHW) pretreated and enzymatically hydrolyzed Sweet Sorghum Bagasse (SSB) hydrolyzates were fermented in a fed‐batch reactor. As reported in the preceding paper, the culture was not able to ferment the hydrolyzate I in a batch process due to presence of high level of toxic chemicals, in particular acetic acid released from SSB during the hydrolytic process. To be able to ferment the hydrolyzate I obtained from 250 g L?1 SSB hydrolysis, a fed‐batch reactor with in situ butanol recovery was devised. The process was started with the hydrolyzate II and when good cell growth and vigorous fermentation were observed, the hydrolyzate I was slowly fed to the reactor. In this manner the culture was able to ferment all the sugars present in both the hydrolyzates to acetone butanol ethanol (ABE). In a control batch reactor in which ABE was produced from glucose, ABE productivity and yield of 0.42 g L?1 h?1 and 0.36 were obtained, respectively. In the fed‐batch reactor fed with SSB hydrolyzates, these productivity and yield values were 0.44 g L?1 h?1 and 0.45, respectively. ABE yield in the integrated system was high due to utilization of acetic acid to convert to ABE. In summary we were able to utilize both the hydrolyzates obtained from LHW pretreated and enzymatically hydrolyzed SSB (250 g L?1) and convert them to ABE. Complete fermentation was possible due to simultaneous recovery of ABE by vacuum. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:967–972, 2018  相似文献   
589.
This article offers insights into the dynamics underlying an increase in marital instability in British Pakistani families, thus challenging stereotypes of British South Asian populations as representing ‘old-fashioned’ families, with their lower rates of divorce in contrast with the wider British population. In addition to problems of compatibility, domestic violence and infidelity, we explore dynamics that may be more specific to the British Pakistani population, namely the transnational nature of many marriages, attitudes to parental involvement in arranging marriages, and the place of Islam. We suggest that, while arranged marriages were conventionally seen as safer than love marriages, both young people and their parents may now be viewing arranged marriages as riskier. In an arranged marriage that brings family approval but not personal fulfilment, young people are increasingly supported to divorce and remarry, with a greater degree of personal say in spouse selection.  相似文献   
590.
The present study investigated the role of kisspeptin-10 on reproductively significant trace elements in relation to testosterone release in male rabbits, Oryctolagus cuniculus. Groups of rabbits were exposed to single 1 μg kisspeptin dose (i.v., saphenous vein), while simultaneous groups were pretreated with a kisspeptin antagonist, peptide-234 (50 μg) 20 min before administering kisspeptin. Sequential blood sampling was done through marginal ear vein puncture at staggered time intervals: 0, 0.5, 1, 2, 4, and 24 h to determine serum testosterone. Testes and whole blood were collected at 4 and 24 h post dosage to determine trace element concentrations through atomic absorption spectrophotometry. In testes, zinc (Zn), manganese (Mn), and Fe concentrations showed significant increases at 24 h, while copper (Cu) concentration was found elevated at 4 and 24 h both (P?<?0.001). In whole blood, Zn and Cu concentrations were significantly elevated at 4 and 24 h, while Mn and cobalt (Co) concentrations showed increases only at 24 h (P?<?0.001). Blood iron concentration was not altered in the blood. In contrast, no change occurred in testicular Co, and chromium or nickel concentrations in either testes or blood. Compared to control and predose groups, serum testosterone levels increased gradually and peaked at 2 h (P?<?0.001) post kisspeptin treatment but declined thereafter. Pretreatment with antagonist abolished all increases in trace elements and testosterone concentrations. The present study provides first evidence that reproduction- and fertility-related peptide “kisspeptin” modulates testicular and blood trace elements and that this action is likely GPR54-dependent.  相似文献   
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