Characterization of Solenopsis invicta virus 4, a polycipivirus infecting the red imported fire ant Solenopsis invicta

Solenopsis invicta virus 4 (SINV-4), a new polycipivirus, was characterized in the host in which it was discovered, Solenopsis invicta. SINV-4 was detected in the worker and larval stages of S. invicta, but not in pupae, male or female alates, or queens. The SINV-4 titer was highest in worker ants, with a mean of 1.14 × 10⁷ ± 5.84 ×10⁷ SINV-4 genome equivalents/ng RNA. Electron microscopic examination of negatively stained samples from particles purified from SINV-4-infected fire ant workers revealed isometric particles with a mean diameter of 47.3 ± 1.4 nm. The mean inter-colony SINV-4 infection rate among S. invicta worker ants was 45.8 ± 38.6 in Alachua County, Florida. In S. invicta collected in Argentina, SINV-4 was detected in 22% of 54 colonies surveyed from across the Formosa region. There did not appear to be any seasonality associated with the SINV-4 infection rate among S. invicta nests. SINV-4 was successfully transmitted to uninfected S. invicta colonies by feeding. Among three colonies of S. invicta inoculated with SINV-4, two retained the infection for up to 72 days. The replicative genome strand of SINV-4 was detected in 18% (n = 11) of SINV-4-infected S. invicta colonies. Among 33 ant species examined, the plus genome strand of SINV-4 was detected in undetermined species of Dorymyrmex and Pheidole, Cyphomyrmex rimosus, Monomorium pharaonis, Pheidole obscurithorax, Solenopsis geminata, Solenopsis richteri, Solenopsis xyloni, and Solenopsis invicta. However, the replicative (minus) genome strand was only detected in S. invicta. SINV-4 infection did not impact brood production or queen fecundity in S. invicta. The mean brood rating (63.3% ± 8.8) after 31 days for SINV-4-infected colonies was not statistically different from that of uninfected colonies (48.3 ± 25.5). At the end of the 31-day test period, mean egg production was not significantly different between SINV-4-infected S. invicta colonies (287.7 ± 45.2 eggs laid/24 hours) and uninfected control colonies (193.0 ± 43.6 eggs laid/24 hours).

Time-dependent immune response in Porcellio scaber following exposure to microplastics and natural particles

Microplastics are very common contaminants in the environment. Despite increasing efforts to assess the effects of microplastics on soil organisms, there remains a lack of knowledge on how organisms respond to diverse types of microplastics after different exposure durations. In the present study, we investigated the immune response of the terrestrial crustacean Porcellio scaber exposed to the two most common microplastic particles in the environment: polyester fibres and tyre particles. We also tested two natural particles: wood dust and silica powder, with all treatments performed at 1.5% w/w. The response of P. scaber was evaluated at the level of the immune system, and also the biochemical, organism and population level, after different exposure durations (1, 2, 4, 7, 14, 21 days). These data reveal dynamic changes in the levels of some immune parameters shortly after exposure, with a gradual return to control values. The total number of haemocytes was significantly decreased after 4 days of exposure to tyre particles, while the proportion of different haemocyte types in the haemolymph was altered shortly after exposure to both polyester fibres and tyre particles. Moreover, 7 days of exposure to tyre particles resulted in increased superoxide dismutase activity in the haemolymph, while metabolic activity in whole woodlice (measured as electron transport system activity) was increased after exposure for 7, 14 and 21 days. In contrast, the natural particles did not elicit any significant changes in the measured parameters. Survival and feeding of P. scaber were not altered by exposure to the microplastics and natural particles in soil. Overall, this study defines a time-dependent transient immune response of P. scaber, which indicates that immune parameters represent sensitive biomarkers of exposure to microplastics. We discuss the importance of using natural particles in studies of microplastics exposure and their effects.

Control of Fusarium verticillioides on corn with a combination of Bacillus subtilis TM3 formulation and botanical pesticides

The aim of this study was to evaluate the effectiveness of the combination of Bacillus subtilis TM3 formulation with botanical pesticides in suppressing Fusarium verticilloides infection in corn. The research was carried out at the Plant Pathology Laboratory and the Experimental Farm of Indonesian Cereals Research Institute (ICERI) from February to November 2019. The research consisted of two stages, namely an in vitro test of antagonists of botanical pesticides against F. verticilloides using 5 types of plant extracts namely betel leaf extract, turmeric, galangal, cosmos, and clove leaf. The second stage was to test the effectiveness of the combination of the formulation of B. subtilis TM3 with the best 3 types of plant extracts in vitro testing in suppressing F. verticilloides infection in plants. The results of the in vitro study showed that the plant extracts of betel leaf, clove leaf and galangal had the best inhibitory ability on the mycelia growth of F. verticilloides. Meanwhile, the field test found that the application of the B. subtilis TM3 formulation, either alone or in combination with plant extracts, was able to suppress F. verticilloides infection. The combination of B. subtilis TM3 formulation with betel leaf extract showed the best inhibition of 20% against stem rot disease and 13.33% against corn cob rot. This treatment did not affect production quantitatively, but was able to suppress the decline in seed quality due to F. verticilloides infection. Seeds grown by the Plastic Rolled Paper Test (PRPT) method were not only infected with F. verticilloides, but also infected with other seed-borne pathogens, such as Aspergillus niger and A. falvus. The presence of these two pathogens did not inhibit the growth of F. verticilloides in kernels.

Cis-regulatory genetic variants in the CCR5 gene and natural HIV-1 control in black South Africans

Studies have investigated CCR5 haplotypes (HHA, HHB, HHC, HHD, HHE, HHF*1, HHF*2, HHG*1, HHG*2), defined by seven 5'UTR single nucleotide polymorphisms (SNPs), CCR2-V64I and CCR5Δ32, in HIV-1 disease. CCR5 cis-regulatory regions were sequenced, CCR2-V64I and CCR5Δ32 genotyped, and compared in HIV-1-infected black South Africans: 71 HIV-1 controllers (23 elite controllers, 37 viraemic controllers (VCs), 11 high viral load long-term non-progressors) and 74 progressors. The HHE haplotype and 3'UTR +2919 T > G SNP heterozygosity were underrepresented in total controllers and VCs vs. progressors (p = .004; p = .007 and p = .002, p_bonferroni = 0.032; p = .004, respectively). Possession of the +2919 T > G SNP (dominant mode) was associated with HIV-1 progression (controllers vs. progressors: p = .001, p_bonferroni = 0.016). The +2919 T > G SNP is in linkage disequilibrium (LD; r² = 0.73) with two 5'UTR SNPs (-2459G > A and -2135 T > C; r² = 1: 5'UTR-2SNP-hap). The 5'UTR-2SNP-hap was lower in total controllers and VCs vs. progressors (p = .003, p_bonferroni = 0.048; p = .01, respectively). Results suggest -2459G > A, -2135 T > C, and + 2919 T > G as key CCR5 variants in HIV-1 control.

Natural control of HIV infection in young women in South Africa: HPTN 068

BACKGROUND

Some individuals control HIV replication without antiretroviral (ARV) therapy.

OBJECTIVE

To analyze viral suppression in young women in rural South Africa enrolled in a trial evaluating a behavioral intervention for HIV prevention.

METHODS

Plasma samples were obtained from women ages 13-24 (81 infected at enrollment, 164 seroconverters). ARV testing was performed using an assay that detects 20 ARV drugs. Women were classified as viremic controllers if they were virally suppressed for ≥12 months with no ARV drug use.

RESULTS

Samples from 216/245 (88.2%) women had no ARV drugs detected at their first HIV-positive visit. Thirty-four (15.7%) of the 216 women had a viral load <2,000 copies/mL. Fifteen of the 34 women were followed for ≥12 months; 12 were virally suppressed with no ARV drugs detected during follow-up. These women were classified as viremic controllers (overall: 12/216 = 5.6%). The median CD4 cell count at the first HIV-positive visit was higher among the 12 controllers than among the 204 women who were not using ARV drugs (759 vs. 549 cells/mm³, p = 0.02). Some women had a viral load <40 copies/mL at a single study visit, but none were classified as elite controllers (viral load <40 copies/mL for ≥12 months with no ARV drug use).

CONCLUSIONS

In this cohort, 5.6% of women who were not using ARV drugs had sustained viral suppression. This represents a minimum estimate of the frequency of viremic controllers in this cohort, since some women were not followed long enough to meet the criteria for classification.

From classic motor imagery to complex movement intention decoding: The noninvasive Graz-BCI approach

In this chapter, we give an overview of the Graz-BCI research, from the classic motor imagery detection to complex movement intentions decoding. We start by describing the classic motor imagery approach, its application in tetraplegic end users, and the significant improvements achieved using coadaptive brain-computer interfaces (BCIs). These strategies have the drawback of not mirroring the way one plans a movement. To achieve a more natural control-and to reduce the training time-the movements decoded by the BCI need to be closely related to the user's intention. Within this natural control, we focus on the kinematic level, where movement direction and hand position or velocity can be decoded from noninvasive recordings. First, we review movement execution decoding studies, where we describe the decoding algorithms, their performance, and associated features. Second, we describe the major findings in movement imagination decoding, where we emphasize the importance of estimating the sources of the discriminative features. Third, we introduce movement target decoding, which could allow the determination of the target without knowing the exact movement-by-movement details. Aside from the kinematic level, we also address the goal level, which contains relevant information on the upcoming action. Focusing on hand-object interaction and action context dependency, we discuss the possible impact of some recent neurophysiological findings in the future of BCI control. Ideally, the goal and the kinematic decoding would allow an appropriate matching of the BCI to the end users' needs, overcoming the limitations of the classic motor imagery approach.

RICH2 is implicated in viraemic control of HIV-1 in black South African individuals

An intronic single nucleotide polymorphism (SNP) in RICH2 (rs2072255; 255ⁱ), in complete linkage disequilibrium (LD) with an exonic SNP (rs2072254; 254^e), has been identified in a genome wide association study to be associated with progression to AIDS in Caucasian individuals. RICH2 links tetherin to the cortical actin network and the RICH2/tetherin interaction has been shown to be important for the downstream activation of NF-κβ and the consequential promotion of proinflammatory responses. We investigated the role of these two SNPs in natural control of HIV-1 in black South Africans including healthy controls (HCs; N=102) and antiretroviral-naive HIV-1-infected controllers (HICs; N=52) and progressors (N=74). HICs were stratified as elite controllers (ECs; N=11), viraemic controllers (VCs; N=30), high viral load (VL) long term non-progressors (HVL LTNPs; N=11) and also according to VL<400RNA copies/ml (HICs VL<400; N=20) and VL>400RNA copies/ml (HICs VL>400; N=32). Results showed that in contrast to Caucasians who had very strong LD between these SNPs (r²=0.97), black populations exhibited low LD (r²=0.11-0.27), however a 254^e minor allele was always present with a 255ⁱ minor allele but not vice versa. The SNPs did not show significant over- or underrepresentation in any particular group, however the combination of 254^e major allele homozygosity and 255ⁱ heterozygosity (254^eAA/255ⁱGA) was underrepresented in HICs (OR=3.26; P=0.04) and VCs (OR=7.77; P=0.02) compared to HCs, and in HICs VL>400 compared to both HCs (P=0.002) and progressors (P=0.02). A lower CD4⁺ T-cell count was associated with 254^eAA/255ⁱGA and 255ⁱ (GA+AA) in the total HIV-1-infected group (P=0.043) and progressors (P=0.017), respectively. In silico analysis predicted loss of an exonic splice enhancer site with the 254^e-G allele. We postulate that altered splicing of RICH2 will affect levels of RICH2 expression and consequently NF-κβ activation. These findings point to a role for RICH2 and tetherin in viraemic natural control of HIV-1.