Serotonergic Innervation of the Salivary Glands and Central Nervous System of Adult Glossina pallidipes Austen (Diptera: Glossinidae), and the Impact of the Salivary Gland Hypertrophy Virus (GpSGHV) on the Host

Using a serotonin antibody and confocal microscopy, this study reports for the first time direct serotonergic innervation of the muscle sheath covering the secretory region of the salivary glands of adult tsetse fly, Glossina pallidipes Austen. Reports to date, however, note that up until this finding, dipteran species previously studied lack a muscle sheath covering of the secretory region of the salivary glands. Direct innervation of the salivary gland muscle sheath of tsetse would facilitate rapid deployment of saliva into the host, thus delaying a host response. Our results also suggest that the neuronal and abnormal pattern seen in viral infected glands by the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV) is due to a compensatory increased branching of the neurons of the salivary glands, which is associated with the increased size of the salivary glands in viral infected flies. This study shows for the first time serotonin in the cell bodies of the brain and thoracico-abdominal ganglion in adult tsetse, G. pallidipes Austen (Diptera: Glossinidae). A hypothesis is proposed as to whether innervation of the muscle sheath covering of the secretory region of the salivary glands is present in brachyceran compared with nematoceran dipterans; and, a plea is made that more research is needed to develop a blood feeding model, similar to that in the blow flies, for elucidating the various mechanisms involved in production and deployment of saliva.     

Ultrastructure of Mesophyll Glands Secreting the Aromatic Substances in Patchouli Leaves

Abstract

The mesophyll gland in patchouli (Pogostemon patchouli) was composed of secretory materials covered with a cuticle, a secretory head cell, a stalk cell and a basal cell. A large number of polysomes, mitochondria and smooth-appearing endoplasmic reticula showing a contracted figure were observed in the secretory head cells. Some endoplasmic reticula were sometimes observed in ramiform profiles. The aromatic cyclic sesquiterpenes were assumed to secrete into a subcuticular space through the thick cell wall from the peripheral area of the secretory head cell. Some cytoplasmic inclusions were localized in the secretory head cells and were considered to have been caused by a viral infection. On the basis of the ultrastructural details of the mesophyll glands, we discuss the secretory machinery by which the cyclic sesquiterpenes are produced and the possibility of the disturbance by viruses of the production of aromatic substances.     

Characterizing the Anti-HIV Activity of Papuamide A

Papuamide A is representative of a class of marine derived cyclic depsipeptides, reported to have cytoprotective activity against HIV-1 in vitro. We show here that papuamide A acts as an entry inhibitor, preventing human immunodeficiency virus infection of host cells and that this inhibition is not specific to R5 or X4 tropic virus. This inhibition of viral entry was determined to not be due to papuamide A binding to CD4 or HIV gp120, the two proteins involved in the cell-virus recognition and binding. Furthermore, papuamide A was able to inhibit HIV pseudotype viruses expressing envelope glycoproteins from vesicular stomatitis virus or amphotropic murine leukemia virus indicating the mechanism of viral entry inhibition is not HIV-1 envelope glycoprotein specific. Time delayed addition studies with the pseudotyped viruses show that papuamide A inhibits viral infection only at the initial stage of the viral life cycle. Additionally, pretreatment studies revealed that the virus, and not the cell, is the target of papuamide A’s action. Together, these results suggest a direct virucidal mechanism of HIV-1 inhibition by papuamide A. We also demonstrate here that the other papuamides (B-D) are able to inhibit viral entry indicating that the free amino moiety of 2,3-diaminobutanoic acid residue is not required for the virucidal activity.     

First report of Cowpea mild mottle virus in chia (Salvia hispanica)

Chia (Salvia hispanica), a herbaceous plant of Lamiaceae family, has gained popularity due to its high concentrations of health-beneficial Omega-3 fatty acids. Plants showing different virus-like symptoms were observed in the principal chia production areas in Argentina. Some plants exhibited yellowing, mottled and blistering leaves, and others shortened internodes and leaf and stem deformation. The aim of this study was to identify the viruses infecting this crop. Forty symptomatic chia plants were collected from nine production fields in northeastern Argentina. The samples were tested for Alfalfa mosaic virus (AMV), Cowpea mild mottle virus (CPMMV), Cucumber mosaic virus (CMV), Tobacco mosaic virus (TMV) and Tospovirus group (I, II and III) by DAS-ELISA, for the genera Potyvirus by PTA-ELISA and for Begomovirus by PCR. CPMMV was detected in three plants with different kind of symptoms. In these plants, feather-like inclusions formed by virions were observed with transmission electron microscopy. ORF2 to ORF6 (2462 nucleotides) from the CPMMV viral genome was amplified by RT-PCR. Nucleotide (nt) sequence of the coat-protein gene (CP – ORF5) of the chia virus isolate was obtained and compared with 31 CPMMV sequences reported in GenBank. Results showed between 75.5% and 99.0% of nt identity, which is above the International Committee on Taxonomy of Viruses criteria for Carlavirus species differentiation. The phylogenetic analysis with the CP gene nt sequences revealed that the CPMMV chia isolate grouped with other CPMMV isolates from other plant species from Brazil, Ghana, India, Puerto Rico, Taiwan and USA, but were separated from four others from India. This is the first report of the presence of CPMMV in chia in the world. Although the other viruses were not detected in this work, it is possible that the different symptoms observed could be produced by a mixture of viruses because CPMMV was found in chia plants with different symptoms.     

Integrated Management of Whitefly, Bemisia tabaci (Gennadius) and Potato Apical Leaf Curl Virus in India

This paper reviews the importance of Potato apical leaf curl virus (PALCV) in India, the biology of its major vector Bemisia tabaci and possible control measures of PALCV and B. tabaci. PALCV has appeared as a new problem in potato growing areas of northwestern plains of India. The first report of PALCV was made from Hissar around 2000. PALCV is a whitefly (B. tabaci) transmitted viral disease and the symptoms are manifested primarily in the form of upward or downward curling of leaves, with 40–75% infection being recorded in cultivars grown in the Indo-Gangetic Plains of India. B. tabaci is a polyphagous pest that feeds on numerous fibre (particularly cotton), food, vegetable and ornamental plants. B. tabaci produces many generations in a year and reaches high population densities. To check the disease incidence, whitefly suppression using imidacloprid either as seed treatment or as foliar application early in the season is recommended. To minimize within-field spread of viruses, removal of virus-infected plants is suggested. Application of mineral and vegetable oils has been found to inhibit virus transmission and possibly can help to avoid difficulties with insecticide resistance in whiteflies.     

Algal Lectins as Potential HIV Microbicide Candidates

The development and use of topical microbicides potentially offers an additional strategy to reduce the spread of the Human Immunodeficiency Virus (HIV). Carbohydrate-binding agents (CBAs) that show specificity for high mannose carbohydrates on the surface of the heavily glycosylated envelope of HIV are endowed with potent anti-HIV activity. In fact, a number of algal lectins such as cyanovirin-N, microvirin, microcystis viridis lectin, scytovirin, Oscillatoria agardhii agglutinin and griffithsin are considered as potential microbicide candidates to prevent the sexual transmission of HIV through topical applications. They not only inhibit infection of cells by cell-free virus but they can also efficiently prevent virus transmission from virus-infected cells to uninfected CD4(+) target T-lymphocytes and DC-SIGN-directed capture of HIV-1 and transmission to CD4(+) T lymphocytes. This review focuses on the structural properties and carbohydrate specificity of these algal lectins, their antiviral activity against HIV and several other enveloped viruses, their safety profile and viral resistance patterns.     

Effect of the ring rot pathogen and latent potato viruses on ring rot symptoms and yield of potatoes

The ring rot bacterium,Corynebacterium sepedonicum (Spieck. and Kotth.) Skapt. and Burkh., and latent potato viruses (potato virus S and potato virus X) were investigated for their effect on ring rot symptom development on potato plants in the greenhouse and on symptom development and yield of potatoes in the field. Both virus-free (VF) and virus-infected (VI) Red Pontiac stem cuttings root-inoculated with ring rot bacteria in the greenhouse developed typical (T) ring rot symptoms, and symptom severity did not differ between VF and VI plants. In a field study, both VF and VI Russet Burbank seed pieces knife-inoculated with ring rot bacteria produced plants with atypical (A) and T ring rot symptoms as well as a combination of both types. The data suggest that more A than T symptoms develop on VI plants and more T than A symptoms develop on VF plants. Combined infection with the ring rot pathogen and the latent potato viruses resulted in greater yield losses of total and marketable Russet Burbank tubers than infection with the bacterial or viral pathogens alone.     

Identification of resistance to Yam mosaic virus (YMV), genus Potyvirus in white Guinea yam (Dioscorea rotundata Poir.)

Yam mosaic virus (YMV), genus Potyvirus; family Potyviridae is the most important virus infecting Dioscorea spp. in the tropics. It induces a variety of symptoms ranging from mild mosaic on leaves of infected plants to stunted growth. Field and laboratory studies were conducted in Nigeria to identify Dioscorea rotundata genotypes that are resistant to YMV. A total of 24 D. rotundata varieties were evaluated in the field under natural infection conditions at four locations in Nigeria during 1998 and 1999 planting seasons, and also in an insect-proof screenhouse using mechanical inoculation and vector transmission. The plants in the field were individually scored for virus symptom severity, while those in the screenhouse were indexed for YMV at 6, 8 and 10 weeks after inoculation by triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). Analysis of the symptom severity scores showed highly significant differences (P<0.01) among the genotypes. Varieties TDr 1621, TDr 1640, TDr 35, TDr 2224 and TDr 93-48 were identified as resistant to field infection by yam viruses based on their low symptom severity scores (<2 on a 1–5 scale). In the screenhouse evaluation by mechanical and vector transmission only TDr 1621, TDr 1640, and TDr 93-48 remained free from YMV infection confirming resistance to YMV in these varieties.     

广西柑橘碎叶病和叶斑病调查及其病原的遗传多样性分析

调查了广西南宁、崇左、柳州、桂林、玉林、河池、贺州及防城港等主要柑橘种植区的柑橘碎叶病和叶斑病的发生情况,并对其病原柑橘碎叶病毒（Citrus tatter leaf virus, CTLV）、苹果茎沟病毒（Apple stem grooving virus, ASGV）和柑橘叶斑病毒（Citrus leaf blotch virus, CLBV）进行了RT-PCR检测、病毒序列测定和遗传多样性分析。结果发现,在所有疑似柑橘病毒病样品中,CTLV检出率为7.3%,CLBV检出率为5.5%,ASGV检出率为3.0%。其中在南宁、桂林和玉林3个主要柑橘种植区采集的疑似柑橘病毒病样品的3种病毒病检出率合计分别为21.2%、28.6%和7.6%,且存在多种病毒复合侵染的现象。将克隆到的上述3个病毒分离物的病毒片段,分别与已报道的相应病毒的代表性分离物的病毒片段进行系统进化分析,结果表明,ASGV和CTLV的中国分离物在进化关系上均呈寄主相关性,ASGV的日本分离物则与地理位置相关性更强,而韩国和印度的分离物未表现出明显的寄主相关性和地理位置相关性。柑橘和苹果的ASGV和CTLV分离物均表现与地理位置相关,而梨的ASGV和CTLV分离物却与地理位置和寄主均不相关;CLBV分离物则呈明显的寄主相关性。本研究首次报道了广西柑橘碎叶病和柑橘叶斑病的发生情况及其病原的遗传多样性与系统进化关系,为柑橘病毒病的诊断和防治提供参考依据。     

Context-Dependent Viral Transgenerational Immune Priming in Honey Bees (Hymenoptera: Apidae)

Transgenerational immune priming is the process of increased resistance to infection in offspring due to parental pathogen exposure. Honey bees (Apis mellifera L. (Hymenoptera: Apidae)) are hosts to multiple pathogens, and this complex immune function could help protect against overwhelming infection. Honey bees have demonstrated transgenerational immune priming for the bacterial pathogen Paenibacillus larvae; however, evidence for viral transgenerational immune priming is lacking across insects in general. Here we test for the presence of transgenerational immune priming in honey bees with Deformed wing virus (DWV) by injecting pupae from DWV-exposed queens and measuring virus titer and immune gene expression. Our data suggest that there is evidence for viral transgenerational immune priming in honey bees, but it is highly context-dependent based on route of maternal exposure and potentially host genetics or epigenetic factors.     

Comparative levels of potato viruses S and Y infection of microplants and tuber-propagated plants in the field

The practice of transplanting microplants from tissue-culture to the field was compared to normal tuber propagation with respect to the transmission and translocation of potato virus S (PVS) and potato virus Y (PVY) to the daughter tubers of Red Pontiac, Shepody, Kennebec, and Russet Burbank cultivars in Prince Edward Island in 1984 and 1985. In general, the use of microplants to produce seed stocks appeared to increase the risk of infection with both viruses, although the results for tuber infection with PVY were only significant in one of the years.     

Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin

Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC₅₀ of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC₅₀s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.     

海南番木瓜PRSV和PLDMV病毒发生情况及分子鉴定

对海南昌江、乐东、澄迈、文昌和三亚5个主要番木瓜产区的病毒病发生情况进行调查。对76份番木瓜疑似病毒样品进行检测,检测结果表明海南番木瓜病毒病主要有2种：由番木瓜环斑病毒（Papaya ring spot virus,PRSV）引起的番木瓜环斑病毒病和由番木瓜畸形花叶病毒（Papaya leaf-distortion mosaic virus,PLDMV）引起的番木瓜畸形花叶病毒病。其中,番木瓜环斑病毒病最为常见,检出率达77.63％,是影响海南地区番木瓜产业健康发展的主要病毒病;畸形花叶病毒病发生率很低,仅检出2例番木瓜畸形花叶病毒病样品。以PRSV病毒基因组P1和Hc-Pro作为靶标基因进行分子克隆、测序,结果表明海南地区PRSV病毒可明显分为2个株系：HN-PRSV-1株系和HN-PRSV-2株系。此外,基于CP基因的系统进化树分析结果表明在海南新发现的PLDMV病毒可能源于台湾和日本。本研究可为开展番木瓜花叶病的防控和创制抗花叶病毒番木瓜新种质提供数据参考。     

Man-Specific,GalNAc/T/Tn-Specific and Neu5Ac-Specific Seaweed Lectins as Glycan Probes for the SARS-CoV-2 (COVID-19) Coronavirus

Seaweed lectins, especially high-mannose-specific lectins from red algae, have been identified as potential antiviral agents that are capable of blocking the replication of various enveloped viruses like influenza virus, herpes virus, and HIV-1 in vitro. Their antiviral activity depends on the recognition of glycoprotein receptors on the surface of sensitive host cells—in particular, hemagglutinin for influenza virus or gp120 for HIV-1, which in turn triggers fusion events, allowing the entry of the viral genome into the cells and its subsequent replication. The diversity of glycans present on the S-glycoproteins forming the spikes covering the SARS-CoV-2 envelope, essentially complex type N-glycans and high-mannose type N-glycans, suggests that high-mannose-specific seaweed lectins are particularly well adapted as glycan probes for coronaviruses. This review presents a detailed study of the carbohydrate-binding specificity of high-mannose-specific seaweed lectins, demonstrating their potential to be used as specific glycan probes for coronaviruses, as well as the biomedical interest for both the detection and immobilization of SARS-CoV-2 to avoid shedding of the virus into the environment. The use of these seaweed lectins as replication blockers for SARS-CoV-2 is also discussed.     

一种E.coli-Free的酵母同源重组系统稳定快速构建PLDMV侵染性克隆的新方法

侵染性克隆是研究病毒的重要工具,而偏大的病毒基因组及其在大肠杆菌中的不稳定给构建侵染性克隆造成很大困难。通常采用插入内含子和酵母同源重组等方式可以获得稳定克隆,但本实验最初利用酵母同源重组系统并未成功构建番木瓜畸形花叶病毒(PLDMV)的侵染性克隆。经研究证实,该不稳定现象确实存在于大肠杆菌中,而非酵母和农杆菌细胞。通过改良酵母同源重组方法,成功构建了有/无内含子intron 2的PLDMV侵染性克隆p35S-FL和p35S-FL-In2,农杆菌注射接种番木瓜均发病,侵染效率达64.7%~69.7%。本研究通过酵母同源重组质粒直接转化农杆菌,建立了一种10 d内即可稳定快速构建PLDMV侵染性克隆的E.coli-Free酵母同源重组新方法。该方法对其他在大肠杆菌中不稳定的植物病毒侵染性克隆的构建具有重要意义。     

Geographic distribution of mealybug wilt disease of pineapple and genetic diversity of viruses infecting pineapple in Cuba

Several species of ampeloviruses and badnaviruses infect pineapple plants around the world. Pineapple mealybug wilt-associated ampeloviruses have been associated with mealybug wilt of pineapple (MWP), the major viral disease threatening this crop. Conversely, infection by the badnaviruses Pineapple bacilliform comosus virus (PBCOV) and Pineapple bacilliform erectifolius virus (PBERV) is asymptomatic. To investigate the status of infection of the pineapple crop in Cuba, a diagnostic survey was developed in commercial areas during the period 2009–2012. Incidence of MWP disease was found in up to 100% of the plants in some fields of Central and Eastern regions of the island. Molecular assays revealed the presence of PMWaV-1 for the first time in the Caribbean basin and PMWaV-2, PMWaV-3, either as mixed infections or in combination with PBCOV throughout the country. Furthermore, they revealed for the first time the presence of PMWaV-2 in Bromelia pinguin L., a plant commonly used in Cuba as hedgerow. Sequence analysis of partial heat shock protein 70h and complete coat protein gene of Cuban isolates of PMWaV-1, -2 and -3 showed nucleotide identities above 97% with cognate sequences of viruses isolated from other countries. This work discloses the presence of a complex of viruses associated with the pineapple crop in Cuba, highlights the potential role of B. pinguin in the PMWaV-mealybug-pineapple pathosystem and makes available diagnostic tools for the detection of viruses affecting pineapple for a seed certified production system in Cuba.     

Myzus persicae (Sulzer) in diffuse light and dark rustic storages and resultant PLRV transmission

Population levels ofMyzus persicae (Sulzer) were studied on potato tubers in diffuse light and dark rustic storage houses in Peru. No differences in numbers of aphids/sprouted eye on potatoes infested naturally during storage in diffuse light or darkness were observed. Significantly more alate aphids were observed on tubers stored in darkness than in diffuse light storage houses. Viral transmission was occurring during the storage period. The incidence of viral transmission was not significantly influenced by storing tubers in diffuse light or dark storages. There were significantly more plants infected with virus from tubers that had not been sprayed for aphid control than from tubers that had been sprayed     

螺旋粉虱成虫消化系统的形态学与组织学研究

应用解剖学和组织学方法研究了螺旋粉虱(Aleurodicus dispersus Russell)成虫消化系统的形态和组织结构。结果显示,螺旋粉虱成虫消化系统由前肠、滤室、中肠、后肠、瓶形孔和一对唾液腺组成。前肠部分主要是食道;中肠包括胃和肠道;后肠分为回肠、结肠和直肠,其中直肠前部有一段膨大的直肠囊;一对唾液腺并行分布在食管下神经节的两侧,呈肾形。消化道管壁从腔内向外依次由黏膜层、肌层和浆膜层等3层结构组成。PAS染色在中肠的胃和肠道中阳性反应最强烈,其次是食道,而在唾液腺和后肠中基本呈阴性;PAS染色阳性部位位于黏膜层,胃和肠道腔内内容物也有阳性反应,而食道腔内无阳性物质。AB染色在后肠中阳性反应最明显,其它部位均呈阴性;AB染色阳性部位位于黏膜层,而肠腔有絮状弱阳性物质。碱性磷酸酶在唾液腺和后肠染色呈阳性,位于整个唾液腺、后肠的黏膜层和肌层;而前肠和中肠染色呈弱阳性,位于黏膜层。     

Impacts of Cucurbit Chlorotic Yellows Virus (CCYV) on Biological Characteristics of Its Vector Bemisia tabaci (Hemiptera: Aleyrodidae) MED Species

Plant viruses can change the phenotypes and defense pathways of the host plants and the performance of their vectors to facilitate their transmission. Cucurbit chlorotic yellows virus (CCYV) (Crinivirus), a newly reported virus occurring on cucurbit plants and many other plant species, is transmitted specifically by Bemisia tabaci MEAM1 (B biotype) and MED (Q biotype) cryptic species in a semipersistent manner. This study evaluated the impacts of CCYV on B. tabaci to better understand the plant-virus-vector interactions. By using CCYV-B. tabaci MED-cucumber as the model, we investigated whether or how a semipersistent plant virus impacts the biology of its whitefly vector. CCYV mRNAs were detectable in nymphs from first to fourth instars and adults of B. tabaci with different titers. Nymph instar durations and adult longevity of female whiteflies greatly extended on CCYV-infected plants, but nymph instar durations and adult longevity of male whiteflies were not significantly influenced. In addition, the body length and oviposition increased in adults feeding on CCYV-infected plants, but the hatching rates of eggs and survival rates of different stages were not affected. Most interestingly, the sex ratio (male:female) significantly reduced to 0.5:1 in whitefly populations on CCYV-infected plants, while the ratio remained about 1:1 on healthy plants. These results indicated that CCYV can significantly impact the biological characteristics of its vector B. tabaci. It is speculated that CCYV and B. tabaci have established a typical mutualist relationship mediated by host plants.     

The infection pressure of potato leafroll virus and potato virus Y in relation to aphid populations in Cyprus

Summary The infection pressure of two viruses, potato leafroll (PLRV) and potato virus Y (PVY), both common in seed potatoes grown in Cyprus, was determined in three experiments in 1982–83. Virus-free bait plants, of potato and four other species, were exposed weekly to field infection during the growing season (March–June), and then returned to an aphid-free glasshouse for symptom expression. Only tobacco plants produced clear symptoms enabling reliable assessment of PVY infection pressure. When assessed with ELISA or by tuber indexing, the potato plants were efficient baits for both viruses whose infection period commenced at emergence (mid March to early April) and ended within 6–7 weeks. The seasonal trend of aphid populations, determined with Moericke traps or 100-leaf counts, correspond to that of virus spread. Correlation and regression analysis of aphid and virus data implicated the alate form ofMyzus persicae as the principal vector of both viruses.