Pathogenesis of mulberry leaf spot in response to meteorological aspects of Kashmir,India

In this study, the influence of climatic factors on the development of leaf spot diseases of mulberry (Morus alba L.) in Kashmir, India was studied. It was found that the highest disease incidence and severity of Goshoerami variety was found in tree type (13.86% and 1.98%) followed by dwarf (7.53% and 1.67%) and bush (3.38% and 0.99%), respectively. Due to infection of pathogen, the relative water content and chlorophyll content of leaves were consistently decreased. The order of reduction in relative water content of infected leaves was found as: bush?>?dwarf?>?tree, while as the reduction in chlorophyll content: bush?>?tree?>?dwarf. It was also found that temperature of 25–30?°C and relative humidity of above 80% favoured the development of the disease. Rapid development of disease was found during the month of June, July and August when average temperature and relative humidity was about 25–30°C and 80%, respectively.     

硝酸银对桑树遗传转化的作用(简报)

调查了硝酸银对农杆菌介导的桑（Morus alba L.)品种“新一之濑”遗传转化的作用。在抗性筛选培养基中添加2mg L^-1硝酸银,桑叶盘褐化死亡率减少7．2％,抗性芽分化率增加3．9％,外源基因转化频率增加9．6％,“假阳性”转化体减少42．5％。感染农杆菌的桑叶盘经MS培养基培养、农杆菌液体培养和固体培养基上划线培养等实验证实,硝酸银对工程农杆菌LBA4404的生长具有抑制作用,这可能是提高桑树转化频率的原因之一。     

桑树种质资源的国内外现状比较

本文简要综述了国内外桑树种质资源收集、保存、鉴定、评价、创新、利用的现状,并通过国内外比较分析,提出了今后我国桑树种质资源应着重开展的工作.     

C-prolinylquercetins from the yellow cocoon shell of the silkworm, Bombyx mori

Two flavonoids containing the l-proline moiety, 6-C-[(2S,5S)-prolin-5-yl] quercetin (prolinalin A) and 6-C-[(2S,5R)-prolin-5-yl] quercetin (prolinalin B), were isolated from the cocoon shell of the silkworm, Bombyx mori. Their structural elucidation was achieved by application of acid hydrolysis and spectroscopic methods. These compounds were not found in the leaves of mulberry (Morus alba L.), the host plant of the silkworm, suggesting that the flavonoids are metabolites of the insect. This is the first time that flavonoids with an amino acid moiety have been found as naturally occurring compounds.     

In vitro screening of some plant extracts against fungal pathogens of mulberry ( Morus spp.)

Twenty one plant species were screened in vitro for their fungitoxic properties against four fungal pathogens viz., Phyllactinia corylea (Powdery mildew), Peridiopsora mori (Brown rust) and Pseudocercospora mori (Black leaf spot) by slide germination method and Myrothecium roridum (Brown leaf spot) by poisoned food technique. Conidial germination of P. corylea was significantly reduced in 5% (w/v) ethanolic extracts all tested plant. Extract of Cassia tora and Cassia sophera completely inhibited conidial germination of P. corylea. Other effective plant extracts inhibited >?90% germination were Allium sativum (99.56%), Ocimum sanctum (97.80%), Moringa oleifera (97.32%). Conidial germination of Pseudocercospora mori was completely inhibited in extract of A. sativum and D. metel. More than 90% inhibition was observed with extract of Holarrhena antidysentrica (93.10%), Adhatoda Zeylanica (91.40%) and Calotropis gigentia (90.40%). Urediniospore germination of Peridiopsora mori was significantly reduced in 19 plant extracts. Extract of A. sativum and D. metel completely inhibited urediniospore germination P. mori. Other effective plant extracts, which inhibited >?90% germination were Calotropis gigentia (99.40%), Targets patula (98.96%), Azadirachta indica (98.85%), Mirabilis jalapa (95.50%) and Chromoleana odorata (90.51%). Maximum inhibition (33.33%) of colony growth of M. roridum was observed with amendment of 5% solvent extracts of D. metel followed by A. sativum (25%), Chromoleana odorata (20%) and Eucalyptus citriodora (16.66%).     

Characterization of a ligand-gated cation channel based on an inositol receptor in the silkworm,Bombyx mori

Insect herbivores recognize non-volatile compounds in plants to direct their feeding behavior. Gustatory receptors (Gr) appear to be required for nutrient recognition by gustatory organs in the mouthparts of insects. Gr10 is expressed in Bombyx mori (BmGr10) mouthparts such as maxillary galea, maxillary palp, and labrum. BmGr10 is predicted to function in sugar recognition; however, the precise biochemical function remains obscure. Larvae of B. mori are monophagous feeders able to find and feed on mulberry leaves. Soluble mulberry leaf extract contains sucrose, glucose, fructose, and myo-inositol. In this study, we identified BmGr10 as an inositol receptor using electrophysiological analysis with the Xenopus oocyte expression system and Ca²⁺ imaging techniques using mammalian cells. These results demonstrated that Xenopus oocytes or HEK293T cells expressing BmGr10 specifically respond to myo-inositol and epi-inositol but do not respond to any mono-, di-, or tri-saccharides or to some sugar alcohols. These inositols caused Ca²⁺ and Na⁺ influxes into the cytoplasm independently of a G protein-mediated signaling cascade, indicating that BmGr10 is a ligand-gated cation channel. Overall, BmGr10 plays an important role in the myo-inositol recognition required for B. mori larval feeding behavior.     

Reduction of post-prandial hyperglycemia by mulberry tea in type-2 diabetes patients

Aim

The dietary contents have a very important role in the management of metabolic syndrome along with type 2 diabetes mellitus (T2DM). Indian diet contains a large amount of carbohydrates that set off unpredictable blood sugar fluctuations and leads to increased risk of diabetic complications. The aim of the present study was to identify the effect of mulberry tea in the reduction of abnormally high postprandial blood glucose (PPG) levels in T2DM patients.

Methods

The study design was follow-up T2DM, 20 diabetic patients were given plain tea (control) and 28 diabetic patients were given mulberry tea (test subject) to measure the effect of mulberry tea on fasting blood glucose and PPG levels. Fasting blood glucose samples were collected after a standard breakfast. The PPG levels were recorded after the consumption of 70 ml tea along with 1 teaspoon of sugar after 90 min in all 48 patients.

Results

Fasting blood glucose levels in control and test group samples were found to be 178.55 ± 35.61 and 153.50 ± 48.10, respectively. After the consumption of plain tea and mulberry tea, the PPG values were recorded as 287.20 ± 56.37 and 210.21 ± 58.73, respectively. A highly significant (p < 0.001) change in the PPG level was observed in response to mulberry tea in all the test patients compared with control. Moreover, the effect size was also found to be very large (1.31).

Conclusion

Mulberry tea suppresses postprandial rise of blood glucose levels after 90 min of its consumption.     

大气氟污染源附近食桑昆虫中氟的积累和分布

对大气F污染源附近野桑蚕,桑赤蠖和桑蚕体内的氟化物含量和器官分布进行了研究,结果表明,污染源附近食桑昆虫体有较高的氟化物含量,且食桑昆虫体的氟化物含量随着离污染源的距离增大而降低,野桑蚕,桑赤蠖和桑蚕的氟化物含量与桑叶的氟化物含量有极显著的线性正相关性,食桑昆虫不同器官间的氟化物积累量也存在较大差异,其消化管是食桑昆虫的主要氟化物积累器官。     

Accumulation of Flavonoid Glycosides and UFGT Gene Expression in Mulberry Leaves (Morus alba L.) before and after Frost

In order to determine the molecular mechanism underlying the influence of frost on chemical changes in mulberry leaves, the UFGT activity, expression level, and accumulation of flavonoid glycosides in mulberry leaves (Morus alba L.) were studied. The expression of UFGT gene was investigated by quantitative real‐time PCR (qRT‐PCR) and the UFGT activity, accumulation of flavonoid glycosides was studied by high performance liquid chromatography. Then, the correlation between the expression level of UFGT, the UFGT activity, and the flavonoid glycosides accumulation with temperature was explored. The accumulation of isoquercitrin and astragalin is significantly positively correlated with UFGT gene expression and UFGT activity. On the contrary, the average temperature was significantly negatively correlated with the level of UFGT gene expression and UFGT activity. The results show that after frost, low temperature can induce the expression of UFGT gene in mulberry leaves, resulting in the accumulation of flavonoid glycosides.     

A novel cellulase gene from the mulberry longicorn beetle, Apriona germari: gene structure, expression, and enzymatic activity

We have previously cloned a cellulase [β-1,4-endoglucanase (EGase), EC 3.2.1.4] cDNA (Ag-EGase I) belonging to glycoside hydrolase family (GHF) 45 from the mulberry longicorn beetle, Apriona germari. We report here the gene structure, expression and enzyme activity of an additional celluase (Ag-EGase II) from A. germari and also described the gene structure of Ag-EGase I. The Ag-EGase II gene spans 1033 bp and consisted of two introns and three exons coding for 239 amino acid residues. The 2713-bp-long genomic DNA of Ag-EGase I also consisted of two introns and three exons. The Ag-EGase II showed 61% protein sequence identity to Ag-EGase I and 51% to another beetle, Phaedon cochleariae, cellulase, belonging to GHF 45. The catalytic sites of GHF 45 are conserved in Ag-EGase II. The Ag-EGase II has 14 conserved cysteine residues and three putative N-glycosylation sites. Northern blot analysis confirmed midgut-specific expression of Ag-EGase II, suggesting that the midgut is the prime site for cellulase synthesis in A. germari larvae. The cDNA encoding Ag-EGase II was expressed as a 36-kDa polypeptide in baculovirus-infected insect Sf9 cells and the enzyme activity of the purified recombinant Ag-EGase II was approximately 812 U/mg of recombinant Ag-EGase II. The enzymatic properties of the purified recombinant Ag-EGase II showed the highest activity at 50 °C and pH 6.0, and were stable at 60 °C at least for 10 min.