Irrigation regimes modulate non-structural carbohydrate remobilization and improve grain filling in rice(Oryza sativa L.)by regulating starch metabolism

Recently developed ‘super’ rice cultivars with greater yield potentials often suffer from the problem of poor grain filling, especially in inferior spikelets. Here, we studied the activities of enzymes related to starch metabolism in rice stems and grains, and the microstructures related to carbohydrate accumulation and transportation to investigate the effects of different water regimes on grain filling. Two ‘super’ rice cultivars were grown under two irrigation regimes of well-watered(WW) and alternate wetting and moderate soil drying(AWMD). Compared with the WW treatment,the activities of ADP glucose pyrophosphorylase(AGPase), starch synthase(StSase) and starch branching enzyme(SBE), and the accumulation of non-structural carbohydrates(NSCs) in the stems before heading were significantly improved, and more starch granules were stored in the stems in the AWMD treatment. After heading, the activities of α-amylase, β-amylase, sucrose phosphate synthase(SPS) and sucrose synthase in the synthetic direction(SSs)were increased in the stems to promote the remobilization of NSCs for grain filling under AWMD. During grain filling, the enzymatic activities of sucrose synthase in the cleavage direction(SSc), AGPase, StSase and SBE in the inferior spikelets were increased, which promoted grain filling, especially for the inferior spikelets under AWMD.However, there were no significant differences in vascular microstructures. The grain yield and grain weight could be improved by 13.1 and 7.5%, respectively, by optimizing of the irrigation regime. We concluded that the low activities of key enzymes in carbon metabolism is the key limitation for the poor grain filling, as opposed to the vascular microstructures, and AWMD can increase the amount of NSC accumulation in the stems before heading, improve the utilization rate of NSCs after heading, and increase the grain filling, especially in the inferior spikelets, by altering the activities of key enzymes in carbon metabolism.

Effects of drought on non-structural carbohydrates and C,N,and P stoichiometric characteristics of Pinus yunnanensis seedlings

To study non-structural carbohydrate character-istics and nutrient utilization strategies of Pinus yunnanen-sis under continuous drought conditions,2-year-old seed-lings were planted in pots with appropriate water,light and moderate and severe drought treatments[(80±5),(65±5),(50±5),and(35±5)%of field water-holding capacity].Non-structural carbohydrates,carbon(C),nitrogen(N),and phosphorus(P)concentrations were measured in each plant component.The results show that:(1)With increasing drought,non-structural carbohydrates gradually increased in leaves,stems,and coarse roots,while gradually decreased in fine roots;(2)C concentrations of all were relatively stable under different stress levels.Phosphorous utilization of each component increased under light and moderate drought conditions,while N and P utilization efficiency of each plant component decreased under severe drought.Growth was mainly restricted by N,first decreasing and then increasing with increased drought;(3)There was a correlation between the levels of non-structural carbohydrates and C,N,and P in each component.Changes in N concentration affected the interconversion between soluble sugar and starch,which play a regulatory role in the fluctuation of the concentration of non-structural carbohydrates;and,(4)Plasticity analysis showed that P.yunnanensis seedlings responded to drought mainly by altering starch concentration,the ratio of soluble sugar to starch in leaves and stems,and further by alter-ing N and P utilization efficiencies.Overall,these results suggest that the physiological activities of all organs of P.yunnanensis seedlings are restricted under drought and that trade-offs exist between different physiological indicators and organs.Our findings are helpful in understanding non-structural carbohydrate and nutrient adaptation mechanisms under drought in P.yunnanensis seedlings.

Impacts of Defoliation on Morphological Characteristics and Non-Structural Carbohydrates of Populus talassica × Populus euphratica Seedlings

Leaves are important‘source’organs that synthesize organic matter,providing carbon sources for plant growth.Here,we used Populus talassica×Populus euphratica,the dominant species in ecological and timber forests,to simulate carbon limitation through artificial 25%,50%,and 75%defoliation treatments and explore the effects on root,stem,and leaf morphology,biomass accumulation,and carbon allocation strategies.At the 60th d after treat-ment,under 25%defoliation treatment,the plant height,specific leaf weight,root surface area and volume,and concentrations of non-structural carbohydrates in stem and root were significantly increased by 9.13%,20.00%,16.60%,31.95%,5.12%,and 9.34%,respectively,relative to the control.There was no significant change in the growth indicators under 50%defoliation treatment,but the concentrations of non-structural carbohydrates in the leaf and stem significantly decreased,showing mostly a negative correlation between them.The opposite was observed in the root.Under 75%defoliation treatment,the plant height,ground diameter,leaf number,single leaf area,root,stem,and total biomass were significantly reduced by 14.15%,10.24%,14.86%,11.31%,11.56%,21.87%,and 16.82%,respectively,relative to the control.The concentrations of non-structural carbohydrates in various organs were significantly reduced,particularly in the consumption of the starch concentrations in the stem and root.These results indicated that carbon allocation strategies can be adjusted to increase the con-centration of non-structural carbohydrates in root and meet plant growth needs under 25%and 50%defoliation.However,75%defoliation significantly limited the distribution of non-structural carbohydrates to roots and stems,reduced carbon storage,and thus inhibited plant growth.Defoliation-induced carbon limitation altered the carbon allocation pattern of P.talassica×P.euphratica,and the relationship between carbon reserves in roots and tree growth recovery after defoliation was greater.This study provides a theoretical basis for the comprehen-sive management of P.talassica×P.euphratica plantations,as well as a reference for the study of plantation car-bon allocation strategies in the desert and semi-desert regions of Xinjiang under carbon-limitation conditions.

Increasing grain weight and yield stability by increasing pre-heading non-structural carbohydrate reserves per spikelet in short-growth duration rice

Rice yield stability is a breeding goal,particularly for short-growth duration rice,but its underlying mechanisms remain unclear.In an attempt to identify the relationship between yield stability and source–sink characteristics in short-growth duration rice,a field experiment was conducted at three sites(Yueyang,Liuyang,and Hengyang)in 2021 and 2022.This study compared yield,yield components,source–sink characteristics,and their stability between two stable-yielding short-growth duration rice cultivars,Zhongzao 39(Z-39)and Lingliangyou 268(L-268),and two unstable-yielding short-growth duration rice cultivars,Zhongjiazao 17(Z-17)and Zhuliangyou 819(Z-819).The stability of agronomic parameters was represented by the coefficient of variation(CV).The respective CVs of yield in Z-17,Z-819,Z-39,and L-268 were 10.2%,10.1%,4.5%,and 5.7%in 2021 and 19.7%,15.0%,5.4%,and 6.5%in 2022.The respective CVs of grain weight were 6.3%,5.7%,3.4%,and 4.5%in Z-17,Z-819,Z-39,and L-268 in 2021,and 8.1%,6.3%,1.5%,and 0.8%in 2022.The mean source capacity per spikelet and pre-heading non-structural carbohydrate reserves per spikelet(NSC_(pre))were 7%–43%and7%–72%lower in Z-819 and Z-17than in L-268 and Z-39 in 2021 and 2022.The mean quantum yield of photosystem II photochemistry of leaf,leaf area index,and specific leaf weight of L-268 and Z-39 were higher than those of Z-819 and Z-17 at the heading stage.This study suggests that high NSC_(pre),caused by great leaf traits before heading,increases source capacity per spikelet and its stability,thereby increasing the stability of grain weight and yield.Increasing NSC_(pre)is critical for achieving grain weight and yield stability in short-growth duration rice.

The contribution of steel wallposts to out-of-plane behavior of non-structural masonry walls

For years,non-structural masonry walls have received little attention by code developers and professional engineers.Recently,significant efforts have been made to shed more light on out-of-plane(OOP)behavior of non-structural masonry walls.In updated provisions of the Iranian seismic code,bed joint reinforcements(BJRs)and steel wallposts have been suggested for use.BJRs are horizontal reinforcements;steel wallposts are vertical truss-like elements intended to provide additional OOP restraints for a wall.The contribution of BJRs has previously been investigated by the authors.This study is devoted to investigating the contribution of steel wallposts to the OOP behavior of non-structural masonry walls.Using pre-validated 3D finite element(FE)models,the OOP behavior of 180 non-structural masonry walls with varying configurations and details are investigated.The OOP pressure-displacement curve,ultimate strength,the response modification factor,and the cracking pattern are among the results presented in this study.It is found that steel wallposts,especially those with higher rigidity,can improve the OOP strength of the walls.The contribution of wallposts in the case of shorter length walls and walls with an opening are more pronounced.Results also indicate that masonry walls with wallpost generally have smaller modification factors compared to similar walls without wallpost.

Study on the Changes of Non-structural Carbohydrates and Nitrogen Contents of Quercus aquifolioides Scrub along Different Elevation Gradient

[Objective] The aim was to compare the content changes between the non-structural carbohydrates（NSC）and the total nitrogen in various growing seasons,and to explore the response relationship between altitude and the contents.[Method] Taking Quercus aquifolioides scrub which widely distributed in Zheduoshan in the west of Sichuan as the experimental objects,the changes between NSC and the toal nitrogen in various growing seasons at different altitude were studied.[Result] The results showed that the content of NSC in Quercus aquifolioides underground increased with the lift of elevation in the dormancy,but decreased in the early germination,growing period and growth stage.The content of NSC in the ground tissue changed non-linearly with increasing elevation.In addition,the total nitrogen of Quercus aquifolioides organizations was decreasing with increasing elevation in the dormant period,which did not change significantly in the other periods.This result implied that the content of NSC in Quercus aquifolioides underground was more sensitive to temperature.[Conclusion] The experiment laid basis for the exploration of the physical and ecological mechanism of underground plants adaptability to highland environment,their response to global climate changes and adjustment to high altitude ecological system.

Effects of Panicle Nitrogen Fertilization on Non-Structural Carbohydrate and Grain Filling in Indica Rice

Grain filling, a crucial stage of grain yield formation in rice, is usually affected by the panicle nitrogen （N） fertilization. Field and pot culture experiments were conducted to explore the underlying mechanisms of N effect. Two rice cultivars with high lodging resistance were grown in the field and pot. Four panicle N fertilization treatments were conducted in 2006 and repeated in 2007. The result showed that medium level of panicle N fertilization treatment （NM） enhanced the accumulation and translocation of non-structural carbohydrate （NSC） in the stem and sheath. Compared with non-nitrogen treatment （NO）, NM promoted the translocation of labeled ^13C from stem and sheath to grain. But, low level of panicle N fertilization treatment （NL） and high level of panicle N fertilization treatment （NH） showed the negative effect. The endosperm cell, grain length, and grain width of NM increased more quickly than that of NO from 4 to 10 d after anthesis. During the early period of grain filling, sucrose-phosphate synthase （EC 2.4.1.14, SPS） activity were significantly higher for the NM treatment than those of the NL and NH treatments. Sucrose synthase （EC 2.4.1.13, SuSase） activity in the grains was substantially enhanced by NM, with the duration of higher activity being longer than those of the other treatments. At maturing stage, NM significantly increased the filled grain number, the seed-setting rate, and the grain weight compared with NL and NH. The results suggest that NM have a positive effect on the activities of enzymes of physiological importance, thereby increasing the grain size and promoting grain filling.

Seismic performance of non-structural components and contents in buildings: an overview of NZ research

This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents.

An immunoglobulin Y that specifically binds to an in silico-predicted unique epitope of Zika virus non-structural 1 antigen

Objective:To identify unique immunogenic epitopes of Zika virus non-structural 1(NS1)antigen and produce immunoglobulin Y(IgY)for potential use in he diagnosis of of Zika virus infection.Methods:Immunogenic epitopes were identified using in silico B-cell epitope prediction.A synthetic peptide analog of the predicted epitope was used to induce antipeptide IgY production in hens which was purified using affinity chromatography.Presence of purified IgY and its binding specificity were performed by gel electrophoresis and ELISA,respectively.Results:Out of the nine continuous epitopes identified,the sequence at position 193-208(LKVREDYSLECDPAVI)was selected and used to produce anti-peptide IgY.The produced IgY was found to bind to the synthetic analog of the Zika virus NS1 immunogenic epitope but not to other flaviviruses and random peptides from other pathogens.Conclusions:In this study,we identified an immunogenic epitope unique to Zika virus that can be used to develop a serodiagnostic tool that specifically detect Zika virus infection.

Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry

BACKGROUND Hepatitis C virus genotype 3a(HCV G3a)is highly prevalent in Pakistan.Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV,medicinal natural products of potent antiviral activity should be screened for the cost-effective treatment of the disease.Furthermore,from natural products,active compounds against vital HCV proteins like non-structural protein 3(NS3)protease could be identified to prevent viral proliferation in the host.AIM To develop cost-effective HCV genotype 3a NS3 protease inhibitors from citrus fruit extracts.METHODS Full-length NS3 without co-factor non-structural protein 4A(NS4A)and codon optimized NS3 protease in fusion with NS4A were expressed in Escherichia coli.The expressed protein was purified by metal ion affinity chromatography and gel filtration.Citrus fruit extracts were screened using fluorescence resonance energy transfer(FRET)assay against the protease and polyphenols were identified as potential inhibitors using electrospray ionization-mass spectrometry(MS)/MS technique.Among different polyphenols,highly potent compounds were screened using molecular modeling approaches and consequently the most active compound was further evaluated against HCV NS4A-NS3 protease domain using FRET assay.RESULTS NS4A fused with NS3 protease domain gene was overexpressed and the purified protein yield was high in comparison to the lower yield of the full-length NS3 protein.Furthermore,in enzyme kinetic studies,NS4A fused with NS3 protease proved to be functionally active compared to full-length NS3.So it was concluded that co-factor NS4A fusion is essential for the purification of functionally active protease.FRET assay was developed and validated by the half maximal inhibitory concentration(IC50)values of commercially available inhibitors.Screening of citrus fruit extracts against the native purified fused NS4A-NS3 protease domain showed that the grapefruit mesocarp extract exhibits the highest percentage inhibition 91%of protease activity.Among the compounds identified by LCMS analysis,hesperidin showed strong binding affinity with the protease catalytic triad having S-score value of-10.98.CONCLUSION Fused NS4A-NS3 protease is functionally more active,which is effectively inhibited by hesperidin from the grapefruit mesocarp extract with an IC50 value of 23.32μmol/L.

Dengue virus non-structural 1 protein interacts with heterogeneous nuclear ribonucleoprotein H in human monocytic cells

Objective: To study protein-protein interaction between heterogeneous nuclear ribonucleoprotein H(hn RNP H) and Dengue virus(DENV) proteins. Methods: DENV proteins were screened against the host hn RNP H protein, in order to identify the host-viral protein-protein interactions in DENV infected THP-1 cells by co-immunoprecipitation. The co-localization of the interacting proteins was further confirmed by immunofluorescence microscopy. Results: The host protein hn RNP H was found to interact with DENV nonstructural 1 protein and help the virus to multiply in the cell. Conclusions: The non-structural 1 glycoprotein is a key modulator of host immune response and is also involved in viral replication. Therefore, disruption of this key interaction between hn RNP H and DENV nonstructural 1 could be an important therapeutic strategy for management of DENV infection.

Non-structural carbohydrate levels of three co-occurring understory plants and their responses to forest thinning by gap creation in a dense pine plantation

We investigated non-structural carbohydrates（NSC） levels and components（starch,glucose,fructose and sucrose） in the leaves of three typical co-occurring forestfloor plants,moss Eurhynchium savatieri（ES）,fern Parathelypteris nipponica（PN） and forb Aruncus sylvester（AS） in a 30-year-old Chinese pine（Pinus tabulaeformis）plantation forest on the eastern Tibetan Plateau.We also explored their responses to three gap creation treatments（control and two gap creations of 80 and 110 m2） based on NSC levels.PN had the highest leaf NSC level of the three plants,with AS second and ES lowest.Starch was the predominant component of NSC and the contents of glucose were higher than those of fructose or sucrose for all three species.The NSC level of ES in intermediate gaps was significantly higher than at control sites.PN also had higher NSC levels in both small and intermediate gaps than in control sites.But the differences between treatments were not obvious for AS.Our results suggest that ES and PN benefit from gap formation while the two species have different NSC response sensitivities to gap size,but the leaf NSC level of AS is less sensitive to the disturbance.

Radial growth and non-structural carbohydrate partitioning response to resin tapping of slash pine(Pinus elliottii Engelm.var.elliottii)

Slash pine(Pinus elliottii Engelm.var.elliottii)is a resin-producing species grown worldwide for significant economic benefits for wood production.Resin tapping cre-ates a carbon sink at the expense of carbon allocation for growth and consequently,wood production may be reduced.Non-structural carbohydrates comprising starch and sugars stored in plant organs,may serve as intermediate pools between assimilation and utilisation.However,the effect of resin tapping between tree growth and non-structural carbo-hydrates is not well understood.This study investigated(1)the effects of resin tapping on radial growth,(2)the effects of resin tapping on non-structural carbohydrate pools in different compartments,and(3)the feasibility of resin pro-duction without disruption of tree growth.Twenty one-year-old slash pines were subjected to resin tapping over two suc-cessive years.Non-structural carbohydrate concentrations in needles,branches,stem phloem,and roots of tapped and untapped trees in summer and winter were determined after the second year of resin harvest.The results showed that tapping had no significant effects on annual increments.Starch was the dominant non-structural carbohydrate frac-tion,regardless of tissues and season,and constituted up to 99%of the total non-structural carbohydrates in the phloem and roots.Glucose and fructose were the dominant sugars;sucrose was negligible.Compared with the controls,tapped trees showed 26%lower non-structural carbohydrate concen-tration in the phloem above the tapping wound in summer,which was attributable to the decreased abundance of starch,glucose,fructose,and sucrose.In winter,the altered non-structural carbohydrate profiles in the phloem above the tap-ping wounding were minimised as a result of recovery of the sugar concentrations.In contrast to free sugars,which accu-mulated substantially in needles and branches during winter,starch was enriched in the phloem,roots,and current-year needles.The results provide evidence for a localised effect of resin tapping,and highlight the observation that resin extrac-tion does not always cause a sacrifice in wood growth under a moderate resin-tapping intensity in slash pine plantations.

Cleft analysis of Zika virus non-structural protein 1

The non-structural protein 1 is an important molecule of the viruses in flavivirus group including to Zika virus. Recently, the NS1 of Zika virus was discovered. There is still no complete information of the molecular interaction of NS1 of Zika virus which can be the clue for explanation for its pathogenesis and further drug search. Here the authors report the cleft analysis of NS1 of Zika virus and the result can be useful for future development of good diagnostic tool and antiviral drug finding for management of Zika virus.

Retraction Note:Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry

Retraction note:Khan M,Rauf W,Habib F,Rahman M,Iqbal M.Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry.World J Hepatol 2020;12(11):976-992 PMID:33312423 DOI:10.4254/wjh.v12.i11.976.The online version of the original article can be found at https://www.wjgnet.com/1948-5182/full/v12/i11/976.htm.

Inhibition of Hepatitis C Virus Genotype 1a Non-Structural Proteins by Small Interference RNA in Human Hepatoma Cell Lines

Hepatitis C virus (HCV) infection and associated liver diseases are still challenging and represent a significant health care burden around the world. Although, the treatment strategies have been improved by the development of novel direct-acting antivirals, but such therapeutic options are still expensive and beyond the financial range of the most infected individuals in developing or even in resource replete countries. It demands an urgent need to search novel and improved alternate treatment strategies to treat the infection. The present study was aimed to develop an in vitro stable cell culture system, persistently expressing HCV genotype 1a non-structural genes and to characterize the inhibitory effects of synthetic siRNAs (short interference RNA) directed against the most conserved regions of nonstructural genes in an in vitro cell culture model. The continuous expression of nonstructural genes for more than 30 days post transfection was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis in stable human hepatoma cell line (Huh-7). The gene expression studies revealed significantly reduced gene expression of HCV nonstructural genes (i.e., NS2, NS4A and NS5A) both at mRNA and protein levels when treated against genome specific synthetic siRNAs in stable cell lines (51%, 47% and 54% respectively, p < 0.05). Similarly, a vivid decrease in HCV viral titer was exhibited by synthetic siRNAs in an in vitro viral replicate cell culture model (58%, 48% and 50%, respectively, p < 0.05) determined by quantitative Real-Time PCR (qPCR). Our data indicate that siRNA mediated gene silencing may be considered a promising alternate treatment strategy against HCV in combination with other effective therapeutic regimens in future.

Potential effect of hepatitis C Virus non-structural protein 4B on liver carcinogenesis

Objective：To investigate the effect of hepatitis C virus non-structural protein 4B（HCV NS4B） on c-Myc, P53, ras gene expression＂ and apoptosis in hepatic cells and study the possible role that NS4B played in the carcinogenesis of heparoma. Methods： The recombinant plasmid（PCXN2-NS4B, PCXN2-P53） and the empty, vector were transfected or co-transfected into Chang liver cells with liposome. Screening was performed with G418. Plasmid mRNA was detected by RT-PCR. The pro rein expressions of c-Myc and ras genes were analyzed by immunocytochemistry. The expressions of wild-type P53 （wtp53） gene were detected by in situ hybridization. TUNEL（flow cytometry） was used for assessing the rate of apoptosis. Results：No expression of c-Myc gene was found in PCXN2 group. The expression of c-Myc gene in NS4B group was 21.3% ＋ 1.2%. The ex pression of ras gene in PCXN2 group was lower than that in NS4B group. Compared with PCXN2 group, the expression of P53 mRNA was not promoted or inhibited in NS4B group. But the expression of P53 mRNA in NS4B-P53 group was lower than that in P53 group. In PCXN2, NS4B, P53 and NS4B-P53 group, the rates of apoptosis were 17.02% ± 1.24%, 11.94% ± 2.24%, 25.84% ± 3.49% and 18.34% ± 1.55% respectively. Conclusion ：HCV NS4B induces the expression of c-Myc and ras gene. HCV NS4B may play a role in the inhibition of cell death through P53-dependent manner. Results from this study suggested that HCV NS4B might contribute to the viral carcinogenesis.

The cloning of non-structural-1 (NS1) gene of H9N2 subtype of avian influenza virus in pGEX-4T-1 and pMAL-c2X plasmids and expression in <i>Escherichia coli</i>DH5<i>α</i>strain

Avian influenza is a viral contagious disease that affects poultry industry and human health. Vaccination has been considered as a preventive tool in the eradication of AI, but it causes some limitations including trade embargoes and interfering with serologic surveillance in differentiation between infected and vaccinated animals (DIVA strategy). Several distinct DIVA strategies have been presented to conquer these limitations. In this study, the open reading frame of NS1 gene of a H9N2 subtype of AI virus was amplified by polymerase chain reaction. After extraction and purification of NS1 gene from agarose gel, it was inserted into two different pGEX-4T-1 and pMAL-c2X plasmids and transferred in DH5α strain of Escherichia coli by using electroporation procedure. The E. coli colonies possessing recombinant NS1 gene were screened using PCR, restriction mapping and sequencing analysis. The expressed rNS1 protein was purified using affinity chromatography based on MBP (pMAL- c2X) and GST (pGEX-4T-1). The MBP-NS1 and GST- NS1 proteins on SDS-PAGE had bands with molecular weight of 68 and 52 kDa respectively. Western blotting with MBP-NS1 protein showed positive reaction using antisera obtained from chickens challenged with a H9N2 subtype strain. But, the most sera prepared from H9N2 vaccinated chickens were negative in WB. These findings indicated that the MBP-rNS1 protein of 26 kDa expressed by pMAL-c2X plasmid can be used in a DIVA for differentiation of AI infected and vaccinated chickens.

Pervious Concrete as an Alternative for Non-structural Drainage to the Amazon Region:From Properties to Applications in Watersheds

The urbanization process of the urban centers in the Amazon occurred quickly and without planning. Belém, one of the main cities in the region, suffers from intense flooding due to urbanization growth and the disorderly occupation of floodplains. The objective was to evaluate the producing of pervious concrete that meets the mechanical and hydraulic performance criteria for permeable pavement molded on site and to simulate the replacement of the entire public walkway system of a hydrographic basin in Belém in order to verify if this measure would alter the permeability of the basin and meet minimum requirements of at least 25% permeable area. The properties of three mixtures of pervious concrete with aggregates of different grading were evaluated. The permeability and flexural strength of all blends were higher than the minimum required for use as a permeable pavement for light vehicle traffic. The simulation showed that replacement of the public walkway by permeable pavement increased the permeable area of the watershed from 19 to 23%, changing from a poor condition to an acceptable level. The results indicate the potential to improve the performance of drainage systems through the wider use of permeable pavement associated with traditional structural measures.

Expression and Activity Analysis of Non-Structural Protein 2 (NS2) of Bombyx mori Densovirus Zhenjiang Strain

The gene of the non-structure protein 2 （NS2） was cloned by PCR from the genome ofBombyx mori densovirus Zhenjiang strain （BmDNV-Z）, inserted into prokaryotic expression vector pET28a to construct recombinant plasmid pET28a-NS2 and then expressed in bacteria Escherichia coli BL21 （DE3）. The expressed recombinant protein was identified by SDS-PAGE and Western blot analysis. Then, the recombinant protein was purified by Ni-NTA column, renatured and tested for enzyme activities. The purified NS2 protein exhibited a helicase activity unwinding double-stranded DNA substrates into single-strand primers, and higher unwinding activity to polarity substrate. Similarly, the purified NS2 protein possessed an ATPase activity and its enzyme activity was 0.276 μmol gg^-1 h^-1 in this study. The results indicated that the non- structure protein which encoded by the gene of BmDNV-Z NS2 possesses the biological activities of helicase and ATPase, and the helicase prefers to polarity substrates. Based on these results, it is speculated that the gene of BmDNV-Z NS2 plays an important role in the viral DNA replication.