scholarly journals Semipersistent Whitefly Transmission of Squash vein yellowing virus, Causal Agent of Viral Watermelon Vine Decline

Plant Disease ◽  
2012 ◽  
Vol 96 (6) ◽  
pp. 839-844 ◽  
Author(s):  
Susan E. Webb ◽  
Scott Adkins ◽  
Stuart R. Reitz
Keyword(s):  
Bemisia Tabaci ◽  
Causal Agent ◽  
Infection Rates ◽  
Transmission Process ◽  
Whitefly Transmission ◽  
The Family ◽  
Vine Decline ◽  
Series Of Experiments ◽  
Short Time ◽  
Yellowing Virus

Squash vein yellowing virus (SqVYV), a recently described Ipomovirus sp. in the family Potyviridae, is the cause of viral watermelon vine decline, a devastating disease in Florida. SqVYV is known to be transmitted by the whitefly, Bemisia tabaci (Gennadius) B strain, but details of the transmission process have not previously been investigated. We completed a series of experiments to determine efficiency of transmission, effects of different acquisition and inoculation access periods, the length of time that whiteflies retained transmissible virus, and the minimum time needed to complete a cycle of acquisition and inoculation. Efficiency was low, with at least 30 whiteflies per plant needed for consistent transmission. Acquisition leading to later transmission peaked at 4 h, and inoculation access periods longer than 4 to 8 h led to no increase in infection rates. Whiteflies retained virus only a short time, with no transmission by 24 h after removal from infected plants. A minimum of 3 h was needed to complete a cycle of transmission under laboratory conditions. These results demonstrate semipersistent transmission of SqVYV and will help refine models of the epidemiology of this virus and the disease it causes.

Host Range Studies for Tomato chlorosis virus, and Cucumber vein yellowing virus Transmitted by Bemisia  tabaci (Gennadius)

2006 ◽  
Vol 114 (3) ◽  
pp. 265-273 ◽  
Author(s):  
Jane Morris ◽  
Elspeth Steel ◽  
Penny Smith ◽  
Neil Boonham ◽  
Nicola Spence ◽  
...  
Keyword(s):  
Host Range ◽  
Bemisia Tabaci ◽  
Tomato Chlorosis Virus ◽  
Yellowing Virus

scholarly journals Genetic Structure of Field Populations of Begomoviruses and of Their Vector Bemisia tabaci in Pakistan

2003 ◽  
Vol 93 (11) ◽  
pp. 1422-1429 ◽  
Author(s):  
Belén Simón ◽  
José Luis Cenis ◽  
Francisco Beitia ◽  
Saif Khalid ◽  
Ignacio M. Moreno ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Bemisia Tabaci ◽  
Random Amplified Polymorphic Dna ◽  
Southeast Asian ◽  
Coi Gene ◽  
Cotton Leaf ◽  
Reading Frame ◽  
Genetic Lineages ◽  
The Family ◽  
Whitefly Vector

The genetic structure of field populations of begomoviruses and their whitefly vector Bemisia tabaci in Pakistan was analyzed. Begomoviruses and B. tabaci populations were sampled from different crops and weeds in different locations in Punjab and Sindh provinces, in areas where cotton leaf curl disease (CLCuD) occurs or does not occur. Phylogenetic analysis based on nucleotide sequences of the intergenic region in the viral DNA-A provided evidence of two clusters of isolates: viruses isolated from species in the family Malvaceae, and viruses isolated from other dicotyledon families. Analysis of the capsid protein (CP) open reading frame grouped isolates into three geographical clusters, corresponding to isolates collected in Punjab, Sindh, or both provinces. Random amplified polymorphic DNA analyses of the B. tabaci population showed that intrapopulation diversity was high at both the local and regional scales. Sequence analysis of the mitocondrial cytochrome oxydase I (mt COI) gene showed that the B. tabaci population was structured into at least three genetic lineages corresponding to the previously described Indian, Southeast Asian, and Mediterranean-African clades. The Indian clade was present only in Punjab, the Mediterranean-African only in Sindh, and the Southeast Asian in both provinces. B. tabaci haplotypes of the Indian clade were found only in the Punjab, where CLCuD occurs. Hence, the geographical distribution of virus and vector genotypes may be correlated, because similar phylogenetic relationships were detected for the viral CP and the vector mt COI genes.

Influence of Insecticides and Reflective Mulch on Watermelon Vine Decline Caused by Squash vein yellowing virus (SqVYV)

2015 ◽  
Vol 16 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Chandrasekar S. Kousik ◽  
Scott Adkins ◽  
Craig G. Webster ◽  
William W. Turechek ◽  
Philip Stansly ◽  
...  
Keyword(s):  
Fruit Quality ◽  
Significant Interaction ◽  
Limiting Factor ◽  
Plastic Mulch ◽  
Central Florida ◽  
Chemical Treatments ◽  
The Past ◽  
Growing Seasons ◽  
Vine Decline ◽  
Yellowing Virus

Watermelon vine decline (WVD) caused by the whitefly-transmitted Squash vein yellowing virus (SqVYV) has been a serious limiting factor in watermelon production in southwest and west-central Florida over the past few years. Symptoms of WVD typically appear as sudden decline of vines a few weeks before harvest or just after the first harvest. Fruit symptoms include rind necrosis and flesh discoloration that affects fruit quality and marketability. The combination of insecticide treatments consisting of an imidacloprid drench (Admire Pro, 560 ml/ha) at transplanting followed by two foliar applications of spiromesifen (Oberon, 2SC, 490 ml/ha) and reflective plastic mulch was evaluated for management of WVD during fall growing seasons of 2006, 2007, and 2009. Virus inoculum source was introduced by planting SqVYV-infected squash plants at the ends of each plot. In all three experiments, the insecticide-treated plots had significantly lower levels of WVD on foliage and fruit compared to non-treated plots. In 2007, the reflective plastic mulch was effective in reducing foliar WVD compared to non-reflective mulch, but not in 2006 and 2009. No significant interaction between plastic mulch and chemical treatments was observed on WVD development on foliage or fruit. Our results suggest that application of insecticides for managing whiteflies can help manage SqVYV-caused WVD. Accepted for publication 13 January 2015. Published 25 March 2015.

Cases Contributed

1885 ◽  
Vol 31 (135) ◽  
pp. 366-371 ◽  
Author(s):  
Percy Smith
Keyword(s):  
Paternal Uncle ◽  
The Family ◽  
Artistic Genius ◽  
Short Time

Case I—B., æt. 53, son of a highly-respected and well-to-do city merchant. One paternal uncle was insane for a short time after business losses; another uncle married a servant, and among his children was a “ne'er-do-well.” Other members of the family have decided musical and artistic genius.

The Incidence of Infection Among Contacts of Poliomyelitis Cases

PEDIATRICS ◽  
1956 ◽  
Vol 17 (1) ◽  
pp. 36-36
Keyword(s):  
Neutralizing Antibodies ◽  
Virus Isolation ◽  
Family Type ◽  
Infection Rates ◽  
Household Contacts ◽  
Serological Examination ◽  
The Family ◽  
Blood Specimens ◽  
Close Contacts

Employing tissue culture technic, the infection rates among close contacts of cases of poliomyelitis was studied during an epidemic. These studies were supplemented with determination of the presence of neutralizing antibodies against poliomyelitis virus in blood specimens. Twenty-four of fifty-four familial associates were found to be positive for the family type of virus; of those from whom no virus was isolated, 25 already had antibodies. Ninety-one per cent of family contacts were either excreting virus or possessed antibodies to the family type. The relation of symptoms to the isolation of virus and the ratio of inapparent to apparent infection among contacts was also studied. The infection rate for household contacts under 15 years of age was 100 per cent. The ratio of inapparent to apparent infection was approximately 3 to 1. The author states that, on the basis of virus isolation and serological examination, poliomyelitis may be considered as contagious as measles among susceptible individuals in a family situation.

Ventilatory afterdischarge and central respiratory drive interactions in the awake goat

1994 ◽  
Vol 76 (1) ◽  
pp. 416-423 ◽  
Author(s):  
M. J. Engwall ◽  
C. A. Smith ◽  
J. A. Dempsey ◽  
G. E. Bisgard
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Time Constant ◽  
Minute Ventilation ◽  
Respiratory Drive ◽  
Arterial Pco2 ◽  
Expiratory Muscle ◽  
Series Of Experiments ◽  
Short Time ◽  
Animal Preparation

We have previously established the existence of ventilatory afterdischarge (VAD) in the awake goat by means of an isolated perfused carotid body (CB) technique. In the present series of experiments we used this animal preparation to examine the effects of systemic (central nervous system) hypoxia, mild hypercapnia, and hypocapnia on the manifestation of VAD in ventilatory variables and respiratory muscle electromyogram activity after hypoxic stimulation of the isolated CB. With systemic isocapnic normoxia, inspired minute ventilation remains above control for 30–40 s (time constant = 16.8 s) after termination of CB hypoxia; however, with systemic hypocapnia, VAD is short (time constant = 5.5 s) and hypoventilation is common after removal of CB stimulation. During mild systemic hypercapnia, VAD is prolonged (time constant = 39.9 s). However, systemic (central nervous system) hypoxia did not decrease VAD (time constant = 17.0 s). These results indicate that the manifestation of VAD is more sensitive to the level of arterial PCO2 and central chemoreceptor activity than it is to the state of central oxygenation. Inspiratory and expiratory muscle electromyogram activities qualitatively tracked ventilation during CB stimulation and during the VAD period in all conditions.

The complete genome sequences of two isolates of cnidium vein yellowing virus, a tentative new member of the family Secoviridae

2015 ◽  
Vol 160 (11) ◽  
pp. 2911-2914 ◽  
Author(s):  
Ran Hee Yoo ◽  
Fumei Zhao ◽  
Seungmo Lim ◽  
Davaajargal Igori ◽  
Sang-Mok Kim ◽  
...  
Keyword(s):  
Complete Genome ◽  
Genome Sequences ◽  
The Family ◽  
Yellowing Virus

scholarly journals Molecular Basis of a Protective/Neutralizing Monoclonal Antibody Targeting Envelope Proteins of both Tick-Borne Encephalitis Virus and Louping Ill Virus

2019 ◽  
Vol 93 (8) ◽  
Author(s):  
Xu Yang ◽  
Jianxun Qi ◽  
Ruchao Peng ◽  
Lianpan Dai ◽  
Ernest A. Gould ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Encephalitis Virus ◽  
Infection Rates ◽  
E Proteins ◽  
E Protein ◽  
Tick Borne Encephalitis ◽  
The Family ◽  
Lateral Ridge ◽  
Louping Ill ◽  
Tick Borne Encephalitis Virus

ABSTRACT Tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) are members of the tick-borne flaviviruses (TBFVs) in the family Flaviviridae which cause encephalomeningitis and encephalitis in humans and other animals. Although vaccines against TBEV and LIV are available, infection rates are rising due to the low vaccination coverage. To date, no specific therapeutics have been licensed. Several neutralizing monoclonal antibodies (MAbs) show promising effectiveness in the control of TBFVs, but the underlying molecular mechanisms are yet to be characterized. Here, we determined the crystal structures of the LIV envelope (E) protein and report the comparative structural analysis of a TBFV broadly neutralizing murine MAb (MAb 4.2) in complex with either the LIV or TBEV E protein. The structures reveal that MAb 4.2 binds to the lateral ridge of domain III of the E protein (EDIII) of LIV or TBEV, an epitope also reported for other potently neutralizing MAbs against mosquito-borne flaviviruses (MBFVs), but adopts a unique binding orientation. Further structural analysis suggested that MAb 4.2 may neutralize flavivirus infection by preventing the structural rearrangement required for membrane fusion during virus entry. These findings extend our understanding of the vulnerability of TBFVs and other flaviviruses (including MBFVs) and provide an avenue for antibody-based TBFV antiviral development. IMPORTANCE Understanding the mechanism of antibody neutralization/protection against a virus is crucial for antiviral countermeasure development. Tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) are tick-borne flaviviruses (TBFVs) in the family Flaviviridae. They cause encephalomeningitis and encephalitis in humans and other animals. Although vaccines for both viruses are available, infection rates are rising due to low vaccination coverage. In this study, we solved the crystal structures of the LIV envelope protein (E) and a broadly neutralizing/protective TBFV MAb, MAb 4.2, in complex with E from either TBEV or LIV. Key structural features shared by TBFV E proteins were analyzed. The structures of E-antibody complexes showed that MAb 4.2 targets the lateral ridge of both the TBEV and LIV E proteins, a vulnerable site in flaviviruses for other potent neutralizing MAbs. Thus, this site represents a promising target for TBFV antiviral development. Further, these structures provide important information for understanding TBFV antigenicity.

An Improved Approach to Audio Segmentation and Classification in Broadcasting Industries

2019 ◽  
Vol 30 (2) ◽  
pp. 44-66
Author(s):  
Jingzhou Sun ◽  
Yongbin Wang
Keyword(s):  
Audio Segmentation ◽  
Audio Processing ◽  
Network Method ◽  
Audio Data ◽  
Series Of Experiments ◽  
Pass Through ◽  
Short Time ◽  
Fully Connected ◽  
Alternative Solutions ◽  
Audio Segmentation And Classification

Audio segmentation and classification are the basis of audio processing in broadcasting industries. A Dual-CNN (Dual-Convolutional Neural Network) method is proposed in this article in which it is possible to pre-train a CNN with unlabeled audio data so as to deal with the scarcity of labeled data. Auto-encoders (including an encoder and a decoder) are utilized, thus the name “Dual.” In the first place, audio sampling points and the derived STFT (Short-Time Fourier Transform) spectrograms pass through their own CNNs. Fusion of the extracted features is then performed. Finally, the merged features are sent to a fully connected network and the classification results are produced via Softmax. Being one of the segmentation-by-classification approaches, our solution also presents a novel smoothing method (SEG-smoothing) in order to deliver the best result of segmentation. A series of experiments have been conducted and their result verifies that the proposed approach for segmentation and classification outperforms alternative solutions.

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