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1.
In investigation was conducted annually from 2002 to 2005 between the second week of May and the end of September on the incidence of scarab beetle, Schizonycha ruficollis (Fabricius) in a teak (Tectona grandis L.f.) nursery at Ramdongari, Nagpur, India. The immature stages, that is white grubs of the scarab beetle damaged 14%-52% of teak seedlings in the nursery beds, whereas the adult of the species, that is scarab beetles, were recorded on three new host trees ( Ziziphus xylopyra, Acacia catechu and A. leucophloea) in addition to the reported hosts such as ziziphus (Z. jujuba and Z. mauritiana). Beetles of the S. ruficollis started emerging from the nursery beds just after the pre-monsoon showers and continued for 10-18 days. While beetle of S. ruficollis defoliated tree hosts available in the surroundings, the immature stages of the beetle caused major damage by feeding on root systerfls of teak seedlings with symptoms of wilting and mortality in forest nursery beds. The result of chemical and biological treatments for the management of grubs of S. ruficollis in nursery beds indicated phorate 10% granular at the rate of 20 g/m^2 and chlorpyriphos 20% emulsifiable concentrate at the rate of 5.0 mL/m^2 to be effective. Grubs of S. ruficollis have not been recorded previously as a major pest of teak (T. grandis). This is also the first report on occurrence of S. ruficollis adults on tree hosts such as Z. xylopyra, A. catechu and A. leucophloea. White grubs being pests of economic importance and the toughest insects to manage, information given in this paper on incidence, pest status and management of Schizonycha ruficollis is of importance to researchers and forest nursery managers.  相似文献   

2.
Human immunodeficiency virus (HIV) is the infectious agent causing acquired immu-nodeficiency syndrome (AIDS),a deadliest scourge of human society. Hepatitis C virus (HCV) is a major causative agent of chronic liver disease and infects an estimated 170 million people worldwide,resulting in a serious public health burden. Due to shared routes of transmission,co-infection with HIV and HCV has become common among individuals who had high risks of blood exposures. Among hemophiliacs the co-infection rate accounts for 85%; while among injection drug users (IDU) the rate can be as high as 90%. HIV can accelerate the progression of HCV-related liver disease,particularly when immunodeficiency has developed. Although the effect of HCV on HIV infection is controversial,most studies showed an increase in mortality due to liver disease. HCV may act as a direct cofactor to fasten the progression of AIDS and decrease the tolerance of highly active antiretroviral therapy (HARRT). Conversely,HAART-related hepatotoxicity may enhance the progression of liver fibrosis. Due to above complications,co-infection with HCV and HIV-1 has imposed a critical challenge in the management of these patients. In this review,we focus on the epidemiology and transmission of HIV and HCV,the impact of the two viruses on each other,and their treatment.  相似文献   

3.
The WNK kinases are a recently discovered family of serine-threonine kinases that have been shown to play an essential role in the regulation of electrolyte homeostasis, lntronic deletions in the WNK1 gene resuk in its overexpression and lead to pseudohypoaldosteronism type Ⅱ, a disease with salt-sensitive hypertension and hyperkalemia. This review focuses on the recent evidence elucidating the structure of the kinase domain of WNK1 and functions of these kinases in normal and disease physiology. Their functions have implications for understanding the biochemical mechanism that could lead to the retention or insertion of proteins in the plasma membrane. The WNK kinases may be able to influence ion homeostasis through its effects on synaptotagmin function.  相似文献   

4.
Nest survival is a vital component of breeding success,and affects population dynamics,as the loss of nests is the main cause of reproductive failure in birds.To identify key factors for the conservation of Chinese grouse Tetrastes sewerzowi,we tested the effects of nest concealment,nest age,nesting season,and habitat edge on nest daily survival rate(DSR)of Chinese grouse using 54 nests found at Lianhuashan Nature Reserve,Gansu,China,2009-2012.Moreover,we controlled for the effect of research activity by testing the effect of nest checks on DSR.Overall,mammal predation caused 93%of nest failures.DSR was 0.986±0.0038 in the constant model and the probability of a nest with a full clutch of 6 eggs surviving the entire 40-day nesting period was 0.526±0.090.DSR decreased with nest age and nesting season(from 19 May to 3 July).Mammals instead of avian predators being responsible for most nest failures suggest that nest sites might be selected to avoid visual avian predators,but not olfactory mammalian predators,and the decreasing trend of DSR with nest age and nesting season could attribute to an additive exposure effect.Moreover,nest checks conducted by investigators significantly lowered nest DSR,especially during the late period of nesting season and for older nests.Mammalian predators might locate the nest site by following the investigator's odor.Based on our results,we suggest that the late incubation stage is a particularly vulnerable period for nest survival of Chinese grouse and those researchers should adjust their activities around nests to balance the need of acquiring accurate data and decreasing nest predation risk.  相似文献   

5.
The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes (Diptera: Glossinidae) were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies was undertaken to determine their activity rhythm while a capture-mark-release-recapture method was conducted to assess the movement and dispersal of tsetse flies between lakeshore, hinterland and further inland sites along a transected area. Dissection of tsetse flies was also undertaken to determine the trypanosome infection rates in salivary glands, proboscis and mid-gut. Results indicated a bimodal diurnal activity profile for G. f fuscipes on the Island, both on the lakeshore and in the hinterland. Movement and dispersal of G. f fuscipes tsetse flies occurred between lakeshore, hinterland and further inland sites with a greater tendency of flies to move to the lakeshore. Trypanosome infection rates of 4.32% for Trypasoma vivax and 1.15% for 7. congolense were found in G. f. fuscipes.  相似文献   

6.
The first case of AIDS was reported in 1985 in China, but by the early 21st century, the government estimated that there were 840,000 citizens living with HIV/AIDS. The number is increasing rapidly. The major risk groups are injection drug users (IDUSs; 43%) and former plasma donors (27%), but rates among heterosexual groups are rising rapidly. Sentinel surveillance was initiated in 1986, and now includes IDUs, men-who-have-sex-with-men, sexually transmitted disease clinic attendees, antenatal women, long-distance truck drivers, and sex workers. Although the government was slow to respond to the epidemic in the late 20th century, it has made a vigorous response in the early 21st century. Components of that response include implementation and evaluation of harm reduction programs for IDUs, education to increase knowledge and reduce stigma, treatment and social support for rural and poor HIV/AIDS patients, widespread testing, and increased funding for HIV/AIDS programs. International agencies have been generous in their support of the government initiatives. To successfully combat the epidemic, China needs to develop and train the necessary infrastructure to implement its intervention programs, particularly in the rural areas, to vigorously combat stigma and discrimination, support research especially in the universities and research institutions other than the China Centers for Disease Control, develop a system for efficient exchange of research and program information, and update legislation to reflect the current situation.  相似文献   

7.
Development data of eggs and pupae ofXyleborusfornicatus Eichh. (Coleoptera: Scolytidae), the shot-hole borer of tea in Sri Lanka, at constant temperatures were used to evaluate a linear and seven nonlinear models for insect development. Model evaluation was based on fit to data (residual sum of squares and coefficient of determination or coefficient of nonlinear regression), number of measurable parameters, the biological value of the fitted coefficients and accuracy in the estimation of thresholds. Of the nonlinear models, the Lactin model fitted experimental data well and along with the linear model, can be used to describe the temperature-dependent development of this species.  相似文献   

8.
正In this Special Issue,a focus is placed on the role of the itdxylem as an essential conduit for the long-distance Edelivery of water and mineral nutrients from the soil to the vegetative(above-ground)regions of the plant Xylem cells destined to form tracheids or vesse members,which will make up the conduit for this water and mineral transport from the roots to the shoots,undergo apoptosis,a process of programmed  相似文献   

9.
DESCRIPTION OF A KUBANOCHOERUS SKULL FROM TONGXIN, NINGXIA   总被引:1,自引:1,他引:0  
<正> A rich Middle Miocene mammalian fauna was discovered in a gully named Maerzuizi Gou, Tongxin County, Ningxia Hui Autonomous Region, in the winter of 1985. Among the fossils is a well preserved skull evidently belonging to Kubanochoerus. It is the third and, as far as we know, the best preserved of its kind so far in the world. A careful study of the skull has enabled us not only to review all the fossils previously discovered and assigned either to Listriodon or to Bunolistriodon in China, but also to clarify in certain degree the evolutionary trend and the classification of that particular group.  相似文献   

10.
Qi H  Pei D 《Cell research》2007,17(7):578-580
The developmental process from a fertilized egg to agrown adult is programmed with remarkable accuracy.While the genetic information of the fertilized egg and itsdescendent somatic cells are the same, it is the selectiveexpressions of the same genome that give rise to the 200or so different cell types in an adult. The differentiatedstates of these adult cells are maintained epigenetically,presumably through the modification of chromatins and theassociated histones. In higher mammals, it was thought thatthe differentiation process is irreversible until the successfulcloning of Dolly [1]. By transferring a nucleus from a fullydifferentiated cell in the mammary gland, Wilmut and col-leagues were able to generate an exact replica of a highermammal, the Doily [1]. This work not only demonstratedthat the genome of differentiated cells can be reprogrammedinto an embryonic state and then to resume a full-fledgeddevelopmental process to generate a normal adult, but alsorejuvenated the field of animal cloning. The prospect thata somatic cell from a patient may be reprogrammed to the  相似文献   

11.
Heart failure continues to be one of the leading causes of morbidity and mortality worldwide.Myocardial infarction is the primary causative agent of chronic heart failure resulting in cardiomyocyte necrosis and the subsequent formation of fibrotic scar tissue.Current pharmacological and non-pharmacological therapies focus on managing symptoms of heart failure yet remain unable to reverse the underlying pathology.Heart transplantation usually cannot be relied on,as there is a major discrepancy between the availability of donors and recipients.As a result,heart failure carries a poor prognosis and high mortality rate.As the heart lacks significant endogenous regeneration potential,novel therapeutic approaches have incorporated the use of stem cells as a vehicle to treat heart failure as they possess the ability to self-renew and differentiate into multiple cell lineages and tissues.This review will discuss past,present,and future clinical trials,factors that influence stem cell therapy outcomes as well as ethical and safety considerations.Preclinical and clinical studies have shown a wide spectrum of outcomes when applying stem cells to improve cardiac function.This may reflect the infancy of clinical trials and the limited knowledge on the optimal cell type,dosing,route of administration,patient parameters and other important variables that contribute to successful stem cell therapy.Nonetheless,the field of stem cell therapeutics continues to advance at an unprecedented pace.We remain cautiously optimistic that stem cells will play a role in heart failure management in years to come.  相似文献   

12.
13.
Lieber MR  Lu H  Gu J  Schwarz K 《Cell research》2008,18(1):125-133
Nonhomologous DNA end joining (NHEJ) is the primary pathway for repair of double-strand DNA breaks in human cells and in multicellular eukaryotes. The causes of double-strand breaks often fragment the DNA at the site of damage, resulting in the loss of information there. NHEJ does not restore the lost information and may resect additional nucleotides during the repair process. The ability to repair a wide range of overhang and damage configurations reflects the flexibility of the nuclease, polymerases, and ligase of NHEJ. The flexibility of the individual components also explains the large number of ways in which NHEJ can repair any given pair of DNA ends. The loss of information locally at sites of NHEJ repair may contribute to cancer and aging, but the action by NHEJ ensures that entire segments of chromosomes are not lost.  相似文献   

14.
The extent and biomass of the Gracilaria beds in the Lüderitz Bay area, Namibia were surveyed in winter and summer. The beds covered most of the suitable sediments available (grain size 106–212 μm) and did not occur in water shallower than 1 m or deeper than 11 m. Total surface area, most of which occurred in the Bay system, changed very little from winter to summer but biomass increased by 3.5 fold. In winter, total Gracilaria biomass was 200 t and 650 t and in summer, 150 t and 2850 t respectively in the Lagoon and Bay. Maximum biomass occurred at 3–4 m in the Lagoon and 5–6 m in the Bay in both winter and summer. Gracilaria beach cast data from 1987 to 1991 for the area were analysed for seasonality and, depending on the specific site, correlated with swell, southerly wind velocity and sea temperature. Beach cast in the Lagoon system is a more continuous process than in the Bay, where beach casts at most sites follow an annual pattern. Wind driven currents and chop were the most important causative parameters of beach cast in the Lagoon whereas the depth at which the plants were growing and swell were more important in the Bay system. The two systems viz. Lagoon and Bay are independent of one another with very little or no exchange of Gracilaria between them. This was evidenced by the similar percentage each contributes to the total beach cast and the similar pattern of beach cast from year to year. The decrease in total beach cast from 1989 to the end of the study period was attributed to a trend towards increasing swell height and low sea temperatures in 1991.  相似文献   

15.
Effects of various concentrations of two heavy metals, namely Cd and Cu, on gametophytes of Laminariajaponica Aresch were determined by recording morphological changes of gametophytes, determining pH values and the heavy metal content of the culture solution, calculating the germination rate of sporophytes, and observing heavy metal (Cd) distribution using a fluorescence microscope. The results showed that heavy metals damaged the gametophytes, and were even lethal, and that the higher the concentration of heavy metal ions, the greater the injury to gametophytes. Gametophytes could not survive in culture solutions containing more than 100 mg/L Cd and 50 mg/L Cu and were only able to survive in culture solution containing a mixture of Cd and Cu up to a concentration of 10 mg/L, which indicates that gametophytes have a higher tolerance to Cd than Cu and that multiple heavy metal ions in solution markedly aggravate the damage to gametophytes compared with individual heavy metal ions. With increases in the concentration of the heavy metal, the burgeoning rate of sporophytes decreased acutely, and solutions containing multiple heavy metal ions caused even more marked harm to sporophytes than solutions containing a single heavy metal ion, because most sporophytes died in mixed solutions. The pH value of the culture medium dropped immediately at the beginning (the first day) of treatment, increased over the following days, and then decreased again. The pH of culture media containing multiple heavy metal ions showed greater variation than media containing a single heavy metal ion, with the extent of the decrease in pH of culture media containing multiple ions being greatest during the last period of the experiment. With increases in the concentration of heavy metals, the capacity of gametophytes to accumulate these ions increased. The blue fluorescent light emitted by the Cd-and Cd-binding protein complex existing in gametophytes in media containing different concentrations of Cd showed clearly the distribution of the ion in gametophytes and the results obtained were consistent with distribution determined using other methods. All results of the present study showed that gametophytes of L. japonica play a remarkable role as heavy metal decontaminators, especially with regard to Cd.  相似文献   

16.
The major of the 2005 Annual Meeting of International Society in Asia is to bring scientists from different parts of the world to present and discuss the most current advances in Interferon and Cytokine Research. Scientific Program  相似文献   

17.
<正> Hapalodectes has long been considered as a small mesonychid specialized toward a carnivorous and piscivorous mode of life. Its rare fossil record was known from the early Eocene of North America and middle and upper Eocene of Asia. Knowledge of this genus is still restricted to two species based mainly on some fragmentary materials.A part of the right mandible of the type species, H. leptognathus, was first described by Osborn and Wortman (1892), but was referred by them to Dissacus, and renamed as Hapalodectes by Matthew (1909). Szalay and Gould (1966) erected a new subfamily, Hapalodectinae, and then all known material were restudied by the former author (Szalay, 1969). No additional material of the genus has been reported since then.The newly discovered specimens described in this paper are the first, and so far the only, cranial evidence of Hapalodectes. The fossils were collected from early Eocene (Ling-cha Formation), Hengdong, Hunan, during two field seasons of 1982-1983. The purpose of the present paper is to place on record the morphology of this well-preserved cranial material and to discuss briefly its significance, it is hoped that the information about the cranial morphology of Hapalodectes will increase our understanding of its relationship with Mesonychidae.We are indebted to Drs. Everett H. Lindsay and Chow Minchen for correcting English summary. We would like to express our gratitude to Dr. Malcolm C. McKenna for his valuable comments and correcting English summary and the facilitating the casts of the type species of Hapalodectes at the American Museum of Natural History. Ms. Ann Bleefield and Meng jin help us to get the casts, Zhai R. j. and Qi T. lend us unpublished material for the comparison, all the photographs are taken by Wang J. f. and figures are drawn by shen W. L., we thank all of them for their kind help.  相似文献   

18.
Aims: We aim to evaluate the water sources of typical riparian arbor species (Populus euphratica) and shrub species (Tamarix ramosissima), and analyze the spatial and temporal dynamics of plant water source in Ejina Delta, the lower reaches of the Heihe River. China. Methods: Eight sampling sites were selected in the riparian zones along the East River and West River in Ejina. The plant xylem water, soil moisture, rainwater, stream water and groundwater were taken and pretreated during the growing season in 2015-2016, and the stable oxygen isotope ratio (δ18O) for each water sample was measured. The δ18O of plant xylem water and soil moisture were compared to estimate the dominant depth of root water uptake, and the linear-mixed model called "IsoSource" were applied to determine plant water sources and quantify their proportions. Important findings: This study indicated that the main recharge sources for P. euphratica and T. ramosissima were stream water and groundwater. The contributions of rain water to them was negligible due to the limited amount and the shallow infiltration depth of local rainfall. As affected by groundwater level fluctuation, soil physical properties, as well as lateral and vertical recharge of stream water on soil moisture, the dominant depth of root water uptake spatially varied. However, the relative contributions of stream water or groundwater to plant water sources did not change significantly across space. Populus euphratica used more stream water (68%), while T. ramosissima used more groundwater (65%). Plant water sources were sensitive to environmental flow controls. The contributions of stream water to the water sources of the two species went up to 84% and 48% for P. euphratica and T. ramosissima respectively during the discharge period, but dropped to 63% and 30% during the non-discharge period. On the other hand, the contributions of groundwater decreased to 16% and 52% during the discharge period, but increased to 37% and 70% during non-discharge period. It is noteworthy that the high similarity of δ18O between stream water and groundwater due to extensive water exchange in the riparian zone made increase the uncertain in quantifying plant water sources.  相似文献   

19.
Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum (L.) Gaertn. (Gramineae) and Bromus inermis Leyss. (Gramineae), two dominant perennial grasses in the Otindag Sandland of China, to different sand water content (SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%) were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar (i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages). At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.  相似文献   

20.
The integration of chemical insecticides and infective juveniles of the entomopathogenic nematode Steinernema carpocapsae (Wesier) (Nematoda: Steinernematidae), to control second instars of the sweetpotato whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) was investigated. Using a sand bioassay, the effects of direct exposure of S. carpocapsae for 24 h to field rate dilutions of four insecticides (spiromesifen, thiacloprid, imidacloprid and pymetrozine) on infectivity to Galleria mellonella larvae were tested. Although all chemicals tested, except spiromesifen, produced acceptable nematode infectivity rates, they were all significantly less than the water control. The effect of insecticide treatment (dry residues of spiromesifen, thiacloprid and pymetrozine and soil drench of imidacloprid) on the efficacy of the nematode against B. tabaci was also investigated. Nematodes in combination with thiacloprid and spiromesifen gave higher B. tabaci mortality (86.5% and 94.3% respectively) compared to using nematodes alone (75.2%) on tomato plants. There was no significant difference in B. tabaci mortality when using the chemicals imidacloprid, pymetrozine and spiromesifen in conjunction with nematodes compared to using the chemicals alone. However, using thiacloprid in combination with the nematodes produced significantly higher B. tabaci mortality than using the chemical alone. The integration of S. carpocapsae and these chemical agents into current integrated pest management programmes for the control of B. tabaci is discussed.  相似文献   

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