Influence of Microalgae Diets on the Biological and Growth Parameters of Oithona nana (Copepoda: Cyclopoida)

Several species of the planktonic free-living genus Oithona have been successfully used in the larviculture of marine fish and shrimp. However, few studies have been published that allow us to estimate the potential of Oithona nana culture under controlled conditions. This work evaluated the effect of the microalgae Isochrysis galbana and Chaetoceros calcitrans as single (200,000 cells/mL) and mixed diets (100,000 + 100,000 cells/mL) on population and individual growth, ingestion rate, number of spawnings, fertility, development time by stage, and sex ratio of O. nana. We cultured this copepod at 28 ± 0.5 °C, 35 PSU salinity, 125 lux, and 12:12 photoperiod. Results showed that diet had no effect on the final population level (6273–7966 ind/L) or on individual growth, nor on sex ratio, with less males than females. With C. calcitrans, O. nana had a higher filtration rate (57 ng C/ind/day). On the other hand, a mixed diet induced a higher number of spawns (0.4 events/day) and nauplii per spawn (23 ind). Similarly, a single or mixed diet, containing I. galbana, accelerated the development rate by 6.33–7.00 days. We concluded that O. nana can be cultured with both microalgae, indicating its potential use in an intensive system for production. However, more research is required to improve the productivity of O. nana rearing.

Population pharmacokinetics of bedaquiline in patients with drug-resistant TB

OBJECTIVE: To develop a population pharmacokinetic (PK) model for bedaquiline (BDQ) to describe the concentration-time data from patients with multidrug-resistant TB (MDR-TB) in China.METHOD: A total of 306 PK observations from 69 patients were used in a non-linear, mixed-effects modelling (NONMEM) approach. BDQ PK can be adequately described by a three-compartment model with a transit absorption model. The impact of baseline covariates, including age, sex, height, weight, alanine aminotransferase (ALT), aspartate aminotransferase (AST), apolipoprotein (ALP), total bilirubin (TBIL), direct bilirubin (DBIL), creatinine (CR), potassium (K+), calcium (Ca++) and magnesium (Mg++) on the oral clearance (CL/F) of BDQ were investigated.RESULTS: In final population PK model, no significant covariates were found in the population PK model for BDQ. The population PK parameter estimate values for oral clearance (CL/F); CL/F between central compartment and peripheral compartment (Q1/F, Q2/F); peripheral volume of distribution (Vp1/F, VP2/F) were respectively 1.50 L/h (95% CI 1.07–1.93), 2.54 L/h (95% CI 1.67–3.41), 1,250 L (95% CI 616.9–1883.1), 2.00 L/h (95% CI 1.10–2.90) and 4,960 L (95% CI 1647.6–8272.4). Inter-individual variability on CL/F was 65.0%.CONCLUSION: This is the first study to establish a population PK model for BDQ in Chinese patients with MDR-TB. The final model adequately described the data and had good simulation characteristics. Despite some limitations, the final population PK model was stable with good accuracy of parameter estimation.

266 Deformation imaging by strain in chronic heart failure over sacubitril–valsartan: a multicentre echocardiographic registry (discover)—ARNI

Aims Sacubitril/valsartan have changed the treatment of heart failure with reduced ejection fraction (HFrEF), due to the positive effects morbidity and mortality partly mediated by left ventricular reverse remodelling (LVRR). The aim of this multicentre study was to identify echocardiographic predictors of LVRR after sacubitril/valsartan administration. Methods and results Patients with HFrEF requiring therapy with sacubitril/valsartan from 13 Italian centres were included. Echocardiographic indexes including speckle tracking echocardiography (STE) indexes were used to predict LVRR [defined as LV end-systolic volume reduction and ejection fraction (LVEF) improvement > 10% at follow-up] at 6 months follow-up as the primary endpoint. Changes in symptoms (NYHA class) and neurohormonal activations [N-terminal-pro-brain natriuretic peptide (NTproBNP)] were also evaluated as secondary endpoints. The final population (excluding patients with poor acoustic windows and missing data) consists of 341 patients [mean age: 65 ± 10 years; 18% female, median LVEF 30% (interquartile range: 25–34)]. At 6 months follow-up, 82 (24%) patients showed early complete response (LVRR and LVEF ≥35%), 55 (16%) early incomplete response (LVRR and LVEF <35%), 204 (60%) no response (no LVRR and LVEF <35%). Non-ischaemic etiology, a lower left atrial volume index and a higher global longitudinal strain were all independent predictors of LVRR at multivariable logistic analysis (all P < 0.01). LA strain was the best predictor of positive changes in NYHA class and NT-proBNP (all P < 0.05) (Figure 1). Conclusions STE parameters at baseline could be useful to predict LVRR and clinical response to sacubitril-valsartan, and thus could be used as a guide for treatment in patients with HFrEF.

Guidance for management of free-roaming community cats: a bioeconomic analysis

Objectives This study used computer simulation modeling to estimate and compare costs of different free-roaming cat (FRC) management options (lethal and non-lethal removal, trap–neuter–return, combinations of these options and no action) and their ability to reduce FRC population abundance in open demographic settings. The findings provide a resource for selecting management approaches that are well matched for specific communities, goals and timelines, and they represent use of best available science to address FRC issues. Methods Multiple FRC management approaches were simulated at varying intensities using a stochastic individual-based model in the software package Vortex. Itemized costs were obtained from published literature and expert feedback. Metrics generated to evaluate and compare management scenarios included final population size, total cost and a cost efficiency index, which was the ratio between total cost and population size reduction. Results Simulations suggested that cost-effective reduction of FRC numbers required sufficient management intensity, regardless of management approach, and greatly improved when cat abandonment was minimized. Removal yielded the fastest initial reduction in cat abundance, but trap–neuter–return was a viable and potentially more cost-effective approach if performed at higher intensities over a sufficient duration. Of five management scenarios that reduced the final population size by approximately 45%, the three scenarios that relied exclusively on removal were considerably more expensive than the two scenarios that relied exclusively or primarily on sterilization. Conclusions and relevance FRCs present a challenge in many municipalities, and stakeholders representing different perspectives may promote varying and sometimes incompatible population management policies and strategies. Although scientific research is often used to identify FRC impacts, its use to identify viable, cost-effective management solutions has been inadequate. The data provided by simulating different interventions, combined with community-specific goals, priorities and ethics, provide a framework for better-informed FRC policy and management outcomes.

Effects of Food Concentration and Photoperiod on Egg Production, Female Life Expectancy and Population Dynamics of the Paracalanid Copepod, Bestiolina amoyensis

The paracalanid copepod, Bestiolina amoyensis, is a widely distributed species occurring in subtropical inshore waters across the Pacific Ocean. Its small size, herbivorous feeding habit, and high adaptability make the species one of the most promising candidates as potential live feed for hatchery larval rearing. This study investigated effects of different feeding density of microalgae Isochrysis spp. (1 × 105, 2 × 105, 3 × 105, 4 × 105, and 5 × 105 cells ml–1) and photoperiod (8L:16D, 12L:12D, and 16L:8D) on productivity-related parameters, including egg production, female life expectancy and population dynamics of B. amoyensis. Results showed that total egg output over female lifespan, final population size and intrinsic rate of population of 12L:12D photoperiod treatments were always the highest among three photoperiod conditions, especially at the food concentration of 4 × 105 cells ml–1, indicating B. amoyensis had high reproductive performance and the population was in a more stable status. The number of nauplii from 4 × 105 cells ml–1 algal concentration treatment accounted for 75% of the population, and the ratio of females to males approaching 1:1 when photoperiod was 12L:12D; female life expectancy was 10.5 ± 0.6 days. In conclusion, our results showed that Isochrysis spp. is a suitable feed for B. amoyensis with an optimal concentration at 4 × 105 cells mL–1; the optimal photoperiod for B. amoyensis rearing is 12L:12D. The relatively long reproductive lifespan and high intrinsic population increase rate make B. amoyensis a good candidate to develop culture techniques for hatchery larval rearing.

First Report of Meloidogyne graminicola on Tomato (Solanum lycopersicum) in Hainan of China

Tomato (Solanum lycopersicum) is an important vegetable crop in Hainan province, Southern China. In this area, rice and tomato rotation is the most common way for tomato cultivation. During March of 2021, in a field of Yazhou District, Sanya City, Hainan Province, leaves of some tomato plants (cv. Jinsheng) turned yellow, although there were no obvious dwarf plants observed. The tomato plants with yellow leaves exhibiting obvious galls on the roots were collected. Several females and gelatinous egg masses of Meloidogyne spp. were found inside the cortex of the root galls after dissection. The perineal patterns of females (n=12) were dorsal-ventrally oval with low and round dorsal arches, lacking obvious lateral lines. Most of the striae were smooth and sometimes short and irregular striae were observed within them. Morphological measurements of females (n=20) included body length (L) = 569.2 ± 53.6 (457.6 - 662.7) µm, body width (BW) = 342.7 ± 69.8 (245.5 - 457.9) µm, stylet = 11.8 ± 0.7 (10.5 - 13.3) µm, dorsal pharyngeal gland orifice to stylet base (DGO) = 4.0 ± 0.2 (3.7 - 4.6) µm, vulval slit length = 24.1 ± 3.7 (16.7 - 30.7) µm, and vulval slit to anus distance = 16.0 ±1.9 (12.6 - 19.3) µm. The second-stage juveniles (J2s, n=20) had the following morphological characters: L = 440.6 ± 26.7 (395.7 - 488.3) µm, BW = 15.9 ± 1.0 (14.5 - 17.9) µm. stylet = 13.5 ± 0.8 (12.3 - 14.9) µm, tail length = 69.5 ± 3.7 (65.4 - 76.9) µm, hyaline tail terminus = 21.0 ± 2.1 (17.3 - 24.9) µm. These morphological characters matched the original description of Meloidogyne graminicola (Golden and Birchfield, 1968). Ten individual females were transferred to ten different tubes for DNA extraction. The species-specific primers Mg-F3 (5'-TTATCGCATCATTTTATTTG-3') and Mg-R2 (5'-CGCTTTGTTAGAAAATGACCCT-3') were used for the identification of M. graminicola (Htay et al. 2016). For the ten DNA samples, a 369 bp fragment was amplified by this pair of primers, confirming their identities as M. graminicola. The mitochondrial DNA (mtDNA) region between COII and the lRNA gene was amplified using primers C2F3 (5’-GGTCAATGTTCAGAAATTTGTGG-3’) and 1108 (5’-TACCTTTGACCAATCACGCT-3’) (Powers and Harris, 1993). A DNA fragment of 531 bp was obtained and the sequence (GenBank Accession No. MZ576221) was 99.8% identical to the sequences of M. graminicola (GenBank Accession Nos. MH033621, MK616527, and MG356945). Part of the rDNA spanning ITS1, 5.8S gene, and ITS2 was amplified with primers 18S (5’-TTGATTACGTCCCTGCCCTTT-3’) and 26S (5’-TTTCACTCGCCGTTACTAAGG-3’) (Vrain et al. 1992). The sequences from the ITS region were 790 bp (GenBank Accession No. MZ312595) and were all 100% identical to the known sequences of M. graminicola (GenBank Accession Nos. MF320126, HM623442, and KY020414). In glasshouse tests, six 30-day-old tomato plants (cv. Jinsheng) were individually transplanted in pots (V sand :V soil = 3:1) and inoculated with 1500 J2s hatched from the egg masses of collected M. graminicola samples per plant. Two non-inoculated tomato plants served as negative controls. After 50 days, inoculated plants had galled roots similar to those encountered in the field and there were J2s and eggs within the galls. The nematode reproduction factor (RF = final population/initial population) was 5.3. No symptoms were observed on control plants. These results confirmed the nematode’s pathogenicity on tomato. To our knowledge, this is the first time of a natural infection of tomato with M. graminicola in China.

The dried fruit mite Carpoglyphus lactis (Acari: Carpoglyphidae) is a suitable alternative prey for Amblyseius herbicolus (Acari: Phytoseiidae)

Being generalist predators makes many members of the Phytoseiidae family a more favourable choice for biocontrol. Amblyseius herbicolus, a predator of several phytophagous pest mites and insects, has recently gained focus as an important biocontrol agent. Most studies focus on providing alternative food such as pollens as a way to increase their persistence on the targets when prey is absent. In this study, we evaluated the developmental and reproductive performance of A. herbicolus on two different diets: the dried fruit mite Carpoglyphus lactis and Raupo Typha orientalis pollen. The groups treated with C. lactis took 7 days to reach adulthood, while the groups treated with pollen took 11 days. The pollen-treated mites did not reproduce but this is likely due to the reduction of pollen quality. When given C. lactis, A. herbicolus produced more than 20 eggs over two weeks and the adults survived 18–19 days. The ratio of A. herbicolus egg to C. lactis adult used (1:20, 40 & 120) in the experiment did not affect the final population size. Cannibalism and competition seemed to affect all treatments, especially those cells started with three A. herbicolus eggs. Under laboratory conditions, A. herbicolus can be successfully cultured using C. lactis, which is an advantageous method for the laboratory and mass rearing of A. herbicolus.

Assessment of the Effect of Different Varieties of Tomato and Hot Pepper on Nematodes Attack in Senegal

Tomato and hot pepper are very susceptible to nematodes. The Parasitic Plant Nematodes (PPN) are controlled using chemicals or resistant varieties. This study focuses on appraising the resistance levels of local and American varieties through the plant characteristics (growth, biomass) and the nematodes metrics (gall index, population). For each crop, three American varieties were tested to ascertain their resistance to the nematodes in Senegal using the following plant materials and protocol. American tomatoe varieties are as follows: Small Fry, Jet Setter, and Celebrity. The hot pepper American varieties include Charleston Bell, Carolina Cayenne, and Carolina Wonder. All of these were provided by the Entomology and Nematology Department and Cooperative Extension Service at the University of Florida. They were compared with highly susceptible Senegalese local varieties which were Roma and Orbit for tomato and Safi for hot pepper. The test was conducted in pots containing sterilized sand of dune and placed in a shelter in a completely randomized design. There were 200 second stage juveniles (J2) of Meloidogyne inoculated in each pot thirteen days after transplantation. After fifty days, plants were uprooted to collect agronomic and nematological parameters. Results for tomato showed, in general, better growth from Roma than the other American tomato varieties. Celebrity offered possibilities of reducing Meloidogyne population, while Small Fry and Jet Setter’s growth were not affected by Meloidogyne populations. Safi, which is the local hot pepper variety, displayed the poorest growth. Carolina Cayenne variety also performed better than Safi in heavy infestations. Analysis of Meloidogyne J2 final population data (in the soil and root) showed a significant difference between Small Fry and Celebrity for tomato. As for hot pepper, Carolina Cayenne performed significantly better than Carolina wonder and Safi. This opens up further research opportunities on the impact of Meloidogyne nematode genus and the agronomic parameters.

Perioperative Chemotherapy with FLOT Scheme in Resectable Gastric Adenocarcinoma: A Preliminary Correlation between TRG and Radiomics

Perioperative chemotherapy (p-ChT) with a fluorouracil plus leucovorin, oxaliplatin, and docetaxel (FLOT) scheme is the gold standard of care for locally advanced gastric cancer. We aimed to test CT radiomics performance in early response prediction for p-ChT. Patients with advanced gastric cancer who underwent contrast enhanced CT prior to and post p-ChT were retrospectively enrolled. Histologic evaluation of resected specimens was used as the reference standard, and patients were divided into responders (TRG 1a-1b) and non-responders (TRG 2-3) according to their Becker tumor regression grade (TRG). A volumetric region of interest including the whole tumor tissue was drawn from a CT portal-venous phase before and after p-ChT; 120 radiomic features, both first and second order, were extracted. CT radiomics performances were derived from baseline CT radiomics alone and ΔRadiomics to predict response to p-ChT according to the TRG and tested using a receiver operating characteristic (ROC) curve. The final population comprised 15 patients, 6 (40%) responders and 9 (60%) non-responders. Among pre-treatment CT radiomics parameters, Shape, GLCM, First order, and NGTDM features showed a significant ability to discriminate between responders and non-responders (p < 0.011), with Cluster Shade and Autocorrelation (GLCM features) having AUC = 0.907. ΔRadiomics showed significant differences for Shape, GLRLM, GLSZM, and NGTDM features (p < 0.007). MeshVolume (Shape feature) and LongRunEmphasis (GLRLM feature) had AUC = 0.889. In conclusion, CT radiomics may represent an important supportive approach for the radiologic evaluation of advanced gastric cancer patients.

Evolutionary transition from a single RNA replicator to a multiple replicator network

In prebiotic evolution, self-replicating molecules are believed to have evolved into complex living systems by expanding their information and functions open-endedly. Theoretically, such evolutionary complexification could occur through successive appearance of novel replicators that interact with one another to form replication networks. Here we performed long-term evolution experiments using an RNA that replicates by a self-encoded RNA replicase. The RNA diversified into multiple coexisting host and parasite lineages, whose frequencies in the population initially fluctuated and gradually stabilized. The final population, comprising five RNA lineages, forms a replicator network with diverse interactions, including cooperation to help the replication of all other members. These results support the capability of molecular replicators to spontaneously develop complexity through Darwinian evolution, a critical step for the emergence of life.