Sub-Cellular Distribution of Zinc in Different Vegetative Organs and Their Contribution to Grains Zinc Accumulation in Rice Under Different Nitrogen and Zinc Supply

Journal of Plant Growth Regulation - Zinc is an important micronutrient for the growth and development of human body and plants. Proper use of nitrogen fertilizer and foliar application of Zn have...     

EFFECTS OF HELPER PROTEINS ENCODED BY p19 AND orf1-orf2 GENES ON Cyt1Aa PROTEIN EXPRESSION IN ACRYSTALLIFEROUS STRAIN OF BACILLUS THURINGIENSIS

A series of plasmids were constructed to examine the effects of p19 and orf1‐orf2 genes from Bacillus thuringiensis on Cyt1Aa synthesis and inclusion formation. The plasmids expressed the cyt1Aa gene along with either p19 or orf1‐orf2, or each of them coordinatively with p20 in the acrystalliferous strain of B. thuringiensis subsp. israelensis 4Q7. No effect on the expression of Cyt1Aa protein was found when P19 or Orf1‐Orf2 co‐expressed with Cyt1Aa. However, when including p20 gene, the constructs with p19 or orf1‐orf2 gene produced lower yield of Cyt1Aa proteins than without p19 or orf1‐orf2 gene. Electron microscopy observation and bioassay showed that P19 and Orf1‐Orf2 have no influence on the crystal size and toxicity of Cyt1Aa protein. It is presumed that P19 and Orf1‐Orf2 might have negative effects on Cyt1Aa synthesis in B. thuringiensis.     

Morphometric Analysis of Hepatocellular carcinoma

Ｍｏｒｐｈｏｍｅｔｒｉｃ　Ａｎａｌｙｓｉｓ　ｏｆ　Ｈｅｐａｔｏｃｅｌｌｕｌａｒ　ｃａｒｃｉｎｏｍａＬａｉＭａｏ－ｄｅ（来茂德）;ＣｈｅｎＰｅｉ－ｈｕｉ（陈培辉）ａｎｄＺｈｏｕＳｈｕｉ－ｙｕｎ（周水云）（ＤｅｐａｒｔｍｅｎｔｏｆＰａｔｈｏｌｏｇｙ,Ｚｈ...     

Biology and life cycle ofAtelocauda koae,an unusual demicyclic rust

Atelocauda koae, a rust of the native HawaiianAcacia koa, is considered as a demicyclic species, having spermogonial, aecial, and telial states, but is unusual in production of aeciospores simultaneously with teliospores rather than consecutively. Host inoculation with spores of each state separately confirmed that the life cycle was perpetuated by the telial state, but the aeciospores, while capable of germination and stomal penetration, did not produce detectable infection. This rust therefore behaves as a microcyclic species, and appears to be in evolutionary transition toward this reduced state. Teliospores produced vestigial, permanently attached basidiosopores which germinated to produce infective hyphae. The hyphae entered the host either through stomata or penetrated the epidermis directly, with the latter method being more common. Unusual nuclear associated with teliospore germination, in which meiosis occurs in more than one diploid nucleus was observed, in confirmation of an earlier study.     

A gene encoding a truncated large subunit of Rubisco is transcribed and salt-inducible in rice

Using the rice salt-tolerant mutant 20 as material, a cDNA library was constructed and two salt-inducible clones, SIR5.5 and SIR8.1, were isolated by differential screening. Homology analysis revealed that the two clones together constituted a chimeric rbcL which encoded a truncated large subunit of Rubisco with 337 amino-acids, plus 64 amino-acids of unknown origin. The expressions of both the normal and the chimeric locus appeared to be developmentally regulated and salt-inducible in shoots of the salt-tolerant mutant 20 and its original variety 77–170. In roots, their expressions were salt-inducible in the salt-tolerant mutant 20 whereas no, or only premature, forms were present in the salt-treated original variety 77–170. Higher concentrations of salt reduced the expressions of both normal rbcL and the chimeric locus. ABA showed no effect on their expression.     

Isolation,characterization and application of a species-specific repeated sequence from Haynaldia villosa

A species-specific repeated sequence, pHvNAU62, was cloned from Haynaldia villosa, a wheat relative of great importance. It strongly hybridized to H. villosa, but not to wheat. In situ hybridization localized this sequence to six of seven H. villosa chromosome pairs in telomeric or sub-telomeric regions. Southern hybridization to whea-H. villosa addition lines showed that chromosomes 1V through 6V gave strong signals in ladders while chromosome 7V escaped detection. In addition to H. villosa, several Triticeae species were identified for a high abundance of the pHvNAU62 repeated sequence, among which Thinopyrum bassarabicum and Leymus racemosus produced the strongest signals. Sequence analysis indicated that the cloned fragment was 292 bp long, being AT rich (61%), and showed 67% homology of pSc7235, a rye repeated sequence. Isochizomer analysis suggested that the present repeated sequence was heavily methylated at the cytosine of the CpG dimer in the genome of H. villosa.It was also demonstrated that pHvNAU62 is useful in tagging the introduced 6VS chromosome arm, which confers a resistance gene to wheat powdery mildew, in the segregating generations.     

RFLP tagging of a salt tolerance gene in rice

A salt tolerant rice mutant (M-20) was obtained through selection in vitro. Its tolerance was stably inherited over eight generations and most traints between M-20 and its sensitive original 77–170 (Oryza sativa) were very similar. By deriving an F₂ population of M-20 × 77–170 and splitting every F₂ individual into two parts, with one part planted in normal conditions and another part in saline conditions, the inheritance of salt tolerance in rice was studied. Under normal conditions, there was no apparent segregation among F₂ individuals. Under saline conditions, however, the segregation of traits was obvious. According to our standards, the ratio of salt sensitive:moderately-tolerant:tolerant plants was 25:42:18, in accordance with a 1:2:1 ratio. It suggested that the improvement of salt tolerance in our materials was induced by the mutation of a major tolerant gene which showed incomplete dominance. By use of 130 RFLP probes distributed throughout the rice genome, the gene was tagged by a single copy DNA probe, RG4, which was located on chromosome 7. The genetic distance between the salt tolerant gene and RG4 was 7.0 ± 2.9 cM. Based on the split method, a method which could be currently used to evaluate the damage of salt stress in rice was proposed.     

An AU-rich element in the 3' untranslated region of the spinach chloroplast petD gene participates in sequence-specific RNA-protein complex formation.

In chloroplasts, the 3' untranslated regions of most mRNAs contain a stem-loop-forming inverted repeat (IR) sequence that is required for mRNA stability and correct 3'-end formation. The IR regions of several mRNAs are also known to bind chloroplast proteins, as judged from in vitro gel mobility shift and UV cross-linking assays, and these RNA-protein interactions may be involved in the regulation of chloroplast mRNA processing and/or stability. Here we describe in detail the RNA and protein components that are involved in 3' IR-containing RNA (3' IR-RNA)-protein complex formation for the spinach chloroplast petD gene, which encodes subunit IV of the cytochrome b6/f complex. We show that the complex contains 55-, 41-, and 29-kDa RNA-binding proteins (ribonucleoproteins [RNPs]). These proteins together protect a 90-nucleotide segment of RNA from RNase T1 digestion; this RNA contains the IR and downstream flanking sequences. Competition experiments using 3' IR-RNAs from the psbA or rbcL gene demonstrate that the RNPs have a strong specificity for the petD sequence. Site-directed mutagenesis was carried out to define the RNA sequence elements required for complex formation. These studies identified an 8-nucleotide AU-rich sequence downstream of the IR; mutations within this sequence had moderate to severe effects on RNA-protein complex formation. Although other similar sequences are present in the petD 3' untranslated region, only a single copy, which we have termed box II, appears to be essential for in vitro protein binding. In addition, the IR itself is necessary for optimal complex formation. These two sequence elements together with an RNP complex may direct correct 3'-end processing and/or influence the stability of petD mRNA in chloroplasts.     

Inputs from upper airway affect firing of respiratory-associated midbrain neurons

Chen, Zibin, and Frederic L. Eldridge. Inputs fromupper airway affect firing of respiratory-associated midbrain neurons. J. Appl. Physiol. 83(1): 196-203, 1997.In 16 decerebrated unanesthetized cats, we studied effects ofneural inputs from upper airway on firing of 62 mesencephalic neuronsthat also developed respiratory-associated (RA) rhythmic firing whenrespiratory drive was high [Z. Chen, F. L. Eldridge, and P.G.Wagner. J. Physiol. (Lond.) 437:305-325, 1991] and on firing of 16 neurons that did notdevelop the rhythmic firing (non-RA neurons). Activity in RA neuronsincreased after mechanical expansion of pharynx (45% of those tested)or larynx (68%) and after stimulation of glossopharyngeal (50%) orsuperior laryngeal nerves (77%). The increased neuronal firingoccurred despite decreases or abolition of respiratory activity(expressed in phrenic nerve). Neuronal firing also increased aftermechanical stimulation of nasal mucosa (66%) or by jetsof air directed into the nares (48%) and after lightbrushing of nasal skin (~40%). Most stimuli led to decreased firingin a smaller number of neurons, and some neurons showed no response.None of the non-RA neurons developed an increase of firing after any ofthe stimuli, although one had decreased firing after stimulation of thesuperior laryngeal nerve. We conclude that inputs from the upper airwayand nasal skin have independent modulatory effects on the samemesencephalic neurons that are stimulated by ascending rhythmic RAinput from the medulla. These findings may have relevance to generationof the sensation of dyspnea.