scholarly journals Implementation of the mixed linear models in experimental infections with WSSV in the withe shrimp Litopenaeus vannamei

2017 ◽  
Vol 43 (3) ◽  
pp. 557-565
Author(s):  
María Alejandra Ramírez-Ruíz ◽  
Raúl Simá-Álvarez ◽  
Edgar Tórres-Irineo ◽  
Rossanna Rodríguez-Canul
Keyword(s):  
Litopenaeus Vannamei ◽  
Host Response ◽  
White Spot Syndrome Virus ◽  
Linear Models ◽  
Severe Infection ◽  
The Other ◽  
Mixed Linear Models ◽  
Dna Injection ◽  
Shrimp Industry ◽  
Experimental Strategies

The White Spot Syndrome Virus has been very detrimental for the shrimp industry. Up to date there is no cure for the disease, thus, it is necessary to implement reliable experimental strategies to evaluate the effect of drugs and the host response during the prognosis of the disease. In this study, we evaluated two ways of infection with WSSV (200 copies WSSV-DNA) (injection and immersion), at constant temperature (26 ± 0.5ºC), in juveniles of Litopenaeus vannamei (4.8 ± 0.38 g) in intermolt stage. In the infection by injection, the organisms were lethargic with reddish appearance 2 days after infection and mortality (100%) was observed within 2-5 days: 63% organisms with light degree of infection [20 copies of DNA & 1-5 Cowdry A-type inclusions in hypertrophied nuclei (CAI)/200 fields], 21% had moderate infection (200 copies of DNA & 1-2 CAI/20 fields) and 16% severely infected (2000 copies of DNA & more than 10 CAI/field). No mortality was observed in the controls. In the infection by immersion, the signs of WSSV were observed 3 days after infection: 38% of mortality was observed during 3-9 days: 25% of the organism with light degree of infection (20 copies of DNA & 1-2 CAI/20 fields), 5% moderately infected (200 copies of DNA & 1-2 CAI/20 fields) and 8% with severe infection (2000 copies of DNA & 1-5 CAI/2 fields. The other 62% organisms were necropsied at day 12 and tested positive to the WSSV-PCR (light infection = 20 copies of DNA), but did not show CAI by histology. No mortality was observed in the controls. For the statistical analysis, the data did not fit the criteria of independence and linearity needed for the analyses of variance, thus we used instead the mixed linear models and were able to observe a better prediction: in the injected organisms, the mortality reached the highest peak at day 5 after infection. In the organisms infected by immersion, the highest peak or mortality was observed at day 9 after infection. The analysis of variance of Kenward-Roger indicated significant differences between the days of mortality (F = 20.1, P = 0.001), as well as among the ways of infection (Random analysis) (P = 0.007).

scholarly journals Prediction model for sap flow in cacao trees under different radiation intensities in the western Colombian Amazon

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juan Carlos Suárez ◽  
Fernando Casanoves ◽  
Marie Ange Ngo Bieng ◽  
Luz Marina Melgarejo ◽  
Julio A. Di Rienzo ◽  
...  
Keyword(s):  
Sap Flow ◽  
Linear Models ◽  
Cost Effective ◽  
Incident Radiation ◽  
Agroforestry Systems ◽  
The Other ◽  
Hydraulic Redistribution ◽  
Mixed Linear Models ◽  
Diurnal Patterns ◽  
Nocturnal Transpiration

AbstractIn this study, we measured diurnal patterns of sap flow (Vs) in cacao trees growing in three types of agroforestry systems (AFs) that differ in the incident solar radiation they receive. We modeled the relationship of Vs with several microclimatic characteristics of the AFs using mixed linear models. We characterized microclimatic variables that may have an effect on diurnal patterns of sap flow: air relative humidity, air temperature, photosynthetically active radiation and vapor pressure deficit. Overall, our model predicted the differences between cacao Vs in the three different AFs, with cacao plants with dense Musaceae plantation and high mean diurnal incident radiation (HPAR) displaying the highest differences compared to the other agroforestry arrangements. The model was also able to predict situations such as nocturnal transpiration in HPAR and inverse nocturnal sap flows indicative of hydraulic redistribution in the other AFs receiving less incident radiation. Overall, the model we present here can be a useful and cost-effective tool for predicting transpiration and water use in cacao trees, as well as for managing cacao agroforestry systems in the Amazon rainforest.

scholarly journals SURVEY OF VIRAL DISEASES OF PACIFIC WHITE SHRIMP, Litopenaeus vannamei IN INDONESIA

2008 ◽  
Vol 3 (1) ◽  
pp. 59 ◽  
Author(s):  
Taukhid Taukhid ◽  
Hambali Supriyadi ◽  
Isti Koesharyani
Keyword(s):  
Litopenaeus Vannamei ◽  
White Spot Syndrome Virus ◽  
Pacific White Shrimp ◽  
White Spot ◽  
White Shrimp ◽  
Viral Diseases ◽  
Shrimp Culture ◽  
Black Tiger Shrimp ◽  
Tiger Shrimp ◽  
Shrimp Industry

Penaeid shrimp culture is a major contributor to foreign exchange earning in Indonesia. It has significant impact on economic development of fisheries sector, and leads to be one of prime mover to improve social prosperity. However, shrimp industry particularly black tiger shrimp (Penaeus monodon) has been facing unpredictable situation due to disease problem. The main constrain in correlation to the development of shrimp industry is disease outbreak, especially caused by viral agents. White Spot Syndrome Virus (WSSV) occurred in 1994, causing mass mortality of black tiger shrimp almost in all of the middle and western part of Indonesia. Due to the disease problem, it is estimated that in year 2000, more than 50% of shrimp pond were idle. Pacific white shrimp (Litopenaeus vannamei) or “udang vanamei” was introduced to Indonesia at the end of 1999, and released officially in July, 2001. Response of shrimp farmers to the shrimp rapidly accepted and distributed to many provinces in the country. At the end of 2006, distribution of white shrimp culture was encountered in more than 15 provinces. The seeds are mainly produced from hatcheries located in East Java and Lampung. The information of TSV in Indonesia was reported firstly from East Java at the end of 2002, without a clear history. Since then, survey of TSV distribution was conducted intensively in white shrimp production areas. Beside TSV, population of white shrimp coming to Indonesia also susceptible to White Spot Syndrome Virus (WSSV) and Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV) infection. A survey with the aim to know significant viral diseases of white shrimp is needed to set up an alternative strategy to control them. The survey was conducted, firstly in the main production centers of white shrimp; and planned to be continued throughout the country. Samples collection, diagnostic method and data compiled in this study were collected from both active and passive surveillance. Diagnosis of viral diseases infecting white shrimp in this study was focused on TSV, WSSV, and IHHNV agents. Polymerase Chain Reaction (PCR) test has been used as a major diagnostic technique in this study. Progress report of the study showed that TSV spreading limited in controlled areas. The study proved that WSSV and IHHNV have been found in cultured white shrimp. All of the diseases mentioned above tend to be a significant constrain of future white shrimp industry in Indonesia, and special attention should be given in order to protect wide-spread of particular disease from infected to uninfected ones. Also, briefly current status of white shrimp culture development in the country will be discussed in this paper.

Inheritance and Correlation Analysis of Main Agronomic Traits in Mungbean (Vigna radiata L.) by Mixed Linear Models

2013 ◽  
Vol 38 (4) ◽  
pp. 624-631
Author(s):  
Chang-You LIU ◽  
Bao-Jie FAN ◽  
Zhi-Min CAO ◽  
Yan WANG ◽  
Zhi-Xiao ZHANG ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Vigna Radiata ◽  
Linear Models ◽  
Agronomic Traits ◽  
Mixed Linear Models

Human density, economic level and frequency of canine helminths in Buenos Aires

2021 ◽  
Vol 95 ◽  
Author(s):  
D. Rubel ◽  
N. Flaibani
Keyword(s):  
Linear Models ◽  
Buenos Aires ◽  
Toxocara Canis ◽  
The Other ◽  
Green Spaces ◽  
Cross Sectional ◽  
Independent Variables ◽  
Economic Level ◽  
Faecal Samples ◽  
Human Density

Abstract The aim of this study was to explore through cross-sectional study the variation in the prevalence of parasitic helminths in canine faeces collected from green spaces of Buenos Aires according to the human density (HD) and economic level (EL) in the surroundings. HD and EL were considered as independent variables with three categories each. Twenty public squares (one hectare of surface) were randomly selected for each existing combination of the two independent variables. Ten random samples of fresh canine faeces were obtained in each square and analysed for helminths by the sedimentation and flotation techniques. The prevalence for each of the species was analysed using generalized linear models (GLM). The prevalence was modelled with a binomial error distribution and a logit link function. Helminth eggs were detected in 45 out of the 200 (22.5%) faecal samples collected and in 18 of the 20 green spaces sampled. The species observed were Ancylostoma caninum (13% of samples), Trichuris vulpis (8%) and Toxocara canis (4.5%). The GLM indicated that the prevalence of A. caninum in the slum areas (very high HD and very low EL) was higher than that in the other areas studied. However, the HD seemed to contribute more than the EL to the variations in the prevalence of A. caninum in faecal samples. The GLM showed no differences in the prevalence of the other parasite species for the different levels of the independent variables.

scholarly journals Charged Residues Flanking the Transmembrane Domain of Two Related Toxin–Antitoxin System Toxins Affect Host Response

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 329
Author(s):  
Andrew Holmes ◽  
Jessie Sadlon ◽  
Keith Weaver
Keyword(s):  
Amino Acid ◽  
Enterococcus Faecalis ◽  
Host Response ◽  
Cytoplasmic Membrane ◽  
Transmembrane Domain ◽  
The Other ◽  
Type I ◽  
Transcriptomic Response ◽  
Specific Amino Acid ◽  
Transporter Protein

A majority of toxins produced by type I toxin–antitoxin (TA-1) systems are small membrane-localized proteins that were initially proposed to kill cells by forming non-specific pores in the cytoplasmic membrane. The examination of the effects of numerous TA-1 systems indicates that this is not the mechanism of action of many of these proteins. Enterococcus faecalis produces two toxins of the Fst/Ldr family, one encoded on pheromone-responsive conjugative plasmids (FstpAD1) and the other on the chromosome, FstEF0409. Previous results demonstrated that overexpression of the toxins produced a differential transcriptomic response in E. faecalis cells. In this report, we identify the specific amino acid differences between the two toxins responsible for the differential response of a gene highly induced by FstpAD1 but not FstEF0409. In addition, we demonstrate that a transporter protein that is genetically linked to the chromosomal version of the TA-1 system functions to limit the toxicity of the protein.

scholarly journals Relationship between Cycling Infrastructure and Transportation Cycling in a Small Urban Area

2021 ◽  
Vol 1 (1) ◽  
pp. 99-112
Author(s):  
Richard Larouche ◽  
Nimesh Patel ◽  
Jennifer L. Copeland
Keyword(s):  
Generalized Linear Models ◽  
Qualitative Data ◽  
Linear Models ◽  
The Other ◽  
Small City ◽  
The Road ◽  
The Past ◽  
Low Prevalence ◽  
The Relationship

The role of infrastructure in encouraging transportation cycling in smaller cities with a low prevalence of cycling remains unclear. To investigate the relationship between the presence of infrastructure and transportation cycling in a small city (Lethbridge, AB, Canada), we interviewed 246 adults along a recently-constructed bicycle boulevard and two comparison streets with no recent changes in cycling infrastructure. One comparison street had a separate multi-use path and the other had no cycling infrastructure. Questions addressed time spent cycling in the past week and 2 years prior and potential socio-demographic and psychosocial correlates of cycling, including safety concerns. Finally, we asked participants what could be done to make cycling safer and more attractive. We examined predictors of cycling using gender-stratified generalized linear models. Women interviewed along the street with a separate path reported cycling more than women on the other streets. A more favorable attitude towards cycling and greater habit strength were associated with more cycling in both men and women. Qualitative data revealed generally positive views about the bicycle boulevard, a need for education about sharing the road and for better cycling infrastructure in general. Our results suggest that, even in smaller cities, cycling infrastructure may encourage cycling, especially among women.

scholarly journals Small Molecule Inhibitors of White Spot Syndrome Virus: Promise in Shrimp Seedling Culture

2021 ◽  
Vol 22 (7) ◽  
pp. 3450
Author(s):  
Lei Liu ◽  
Li-Peng Shan ◽  
Yan Zhou ◽  
Jiong Chen
Keyword(s):  
Litopenaeus Vannamei ◽  
White Spot Syndrome Virus ◽  
Environmental Issues ◽  
Therapeutic Strategies ◽  
Effective Concentration ◽  
White Spot ◽  
Rapid Production ◽  
White Spot Syndrome ◽  
Median Effective Concentration ◽  
Artificial Pressure

Rapid production of prawn (Litopenaeus vannamei) under artificial pressure can result in a series of obvious challenges and is vulnerable to serious losses related to aquatic environmental issues and the unrestrained outbreak of white spot syndrome (WSS). However, to date, there are no therapeutic strategies to contain the spread of the virus. Here, we synthesized 27 coumarin deriv-atives and evaluated their anti-white spot syndrome virus (WSSV) activity in L. vannamei larvae. We demonstrated that electron-withdrawing and electron-giving substituent groups play an im-portant role in reducing toxicity and WSSV replication, respectively. Two coumarin C2 (2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) and C7 (2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) were regarded as the most promising anti-WSSV compounds with maximum antiviral response <5% and median effective concentration <10 mg/L. The mortality of WSSV-infected larvae decreased by more than 60% after exposure to C2 and C7. With continuous immersion of C2 and C7 exchange, the mortality further decreased to 40% at 120 h.Additionally, C2 and C7 are the relatively stable in aquacultural water, making these agents

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