Do Dominant Native Ants Outcompete the Invasive Argentine Ant in Mediterranean Citrus Ecosystems? A Laboratory Test.

The invasive Argentine ant (Linepithema humile) poses a significant threat to ecosystem stability worldwide. In Mediterranean citrus ecosystems, its spread may be limited by interactions with dominant native ant species. We conducted laboratory experiments to investigate the competitive dynamics between Argentine ants and two major native species, Tapinoma nigerrimum and Lasius grandis. At the individual level, both native species exhibited superior competitive performance, attributed to their larger body sizes and potential differences in chemical defences. At the colony level, T. nigerrimum demonstrated efficiency in interference competition, successfully defending food resources from Argentine ants. However, the Argentine ant exhibited higher recruitment capacity, albeit it was density-dependent. Our findings support the hypothesis that dominant native ants can serve as barriers against Argentine ant invasion in citrus ecosystems, highlighting the importance of interspecific competition in shaping community dynamics and invasive species management. This study underscores the potential role of native ant species in mitigating the impacts of invasive ants on ecosystem functioning and biodiversity conservation in agricultural landscapes, offering valuable insights for invasive species management strategies in Mediterranean citrus ecosystems.

An Arabidopsis mutant line lacking the mitochondrial calcium transport regulator MICU shows an altered metabolite profile.

Plant metabolism is constantly changing and requires input signals for efficient regulation. The mitochondrial calcium uniporter (MCU) couples organellar and cytoplasmic calcium oscillations leading to oxidative metabolism regulation in a vast array of species. In Arabidopsis thaliana, genetic deletion of AtMICU leads to altered mitochondrial calcium handling and ultrastructure. Here we aimed to further assess the consequences upon genetic deletion of AtMICU. Our results confirm that AtMICU safeguards intracellular calcium transport associated with carbohydrate, amino acid, and phytol metabolism modifications. The implications of such alterations are discussed.

Characterisation of TcFUT1, a mitochondrial fucosyltransferase from Trypanosoma cruzi.

Previous work has shown that the TbFUT1 and LmjFUT1 genes encode essential fucosyltransferases located inside the single mitochondria of the protozoan parasites Trypanosoma brucei and Leishmania major, respectively. However, nothing was known about the orthologous gene TcFUT1 or its gene product in Trypanosoma cruzi, aetiological agent of Chagas disease. In this study, we describe the overexpression of TcFUT1 with a C-terminal 6xMyc epitope tag in T. cruzi epimastigote cells. Overexpressed and immunoprecipitated TcFUT1-6xMyc was used to demonstrate enzymatic activity and to explore substrate specificity. This defined TcFUT1 as a GDP-Fuc : ßGal α1-2 fucosyltransferase with a strict requirement for acceptor glycans with non-reducing terminal Galß1-3GlcNAc structures. This differs from the specificity of the T. brucei orthologue TbFUT1, which can also tolerate non-reducing terminal Galß1-4GlcNAc and Galß1-4Glc acceptor sites. Immunofluorescence microscopy using α-Myc tag antibodies also showed a mitochondrial location for TcFUT1 in T. cruzi epimastigote cells. Collectively, these results are like those described for TbFUT1 and LmjFUT1 from T. brucei and L. major, suggesting that FUT1 gene products have conserved function for across the trypanosomatids and may share therapeutic target potential.

Insights into the origin of the invasive populations of Trioza erytreae in Europe using microsatellite markers and mtDNA barcoding approaches.

The African citrus psyllid Trioza erytreae is one of the major threats to citrus industry as the vector of the incurable disease known as huanglongbing (HLB) or citrus greening. The psyllid invaded the northwest of the Iberian Peninsula 6 years ago. The invasion alarmed citrus growers in the Mediterranean basin, the largest citrus producing area in Europe, which is still free of HLB. Before our study, no research had been carried out on the genetic diversity of T. erytreae populations that have invaded the Iberian Peninsula and the archipelagos of the Macaronesia (Madeira and the Canary Islands). In this study, combining microsatellites markers and mtDNA barcoding analysis, we characterize the genetic diversity, structure and maternal relationship of these new invasive populations of T. erytreae and those from Africa. Our results suggest that the outbreaks of T. erytreae in the Iberian Peninsula may have derived from the Canary Islands. The populations of T. erytreae that invaded Macaronesia and the Iberian Peninsula are likely to have originated from southern Africa. We anticipate our results to be a starting point for tracking the spread of this invasive pest outside of Africa and to be important for optimizing contingency and eradication plans in newly invaded and free areas.

Redefining COVID-19 Severity and Prognosis: The Role of Clinical and Immunobiotypes.

Background: Most of the explanatory and prognostic models of COVID-19 lack of a comprehensive assessment of the wide COVID-19 spectrum of abnormalities. The aim of this study was to unveil novel biological features to explain COVID-19 severity and prognosis (death and disease progression). Methods: A predictive model for COVID-19 severity in 121 patients was constructed by ordinal logistic regression calculating odds ratio (OR) with 95% confidence intervals (95% CI) for a set of clinical, immunological, metabolomic, and other biological traits. The accuracy and calibration of the model was tested with the area under the curve (AUC), Somer's D, and calibration plot. Hazard ratios with 95% CI for adverse outcomes were calculated with a Cox proportional-hazards model. Results: The explanatory variables for COVID-19 severity were the body mass index (BMI), hemoglobin, albumin, 3-Hydroxyisovaleric acid, CD8+ effector memory T cells, Th1 cells, low-density granulocytes, monocyte chemoattractant protein-1, plasma TRIM63, and circulating neutrophil extracellular traps. The model showed an outstanding performance with an optimism-adjusted AUC of 0.999, and Somer's D of 0.999. The predictive variables for adverse outcomes in COVID-19 were severe and critical disease diagnosis, BMI, lactate dehydrogenase, Troponin I, neutrophil/lymphocyte ratio, serum levels of IP-10, malic acid, 3, 4 di-hydroxybutanoic acid, citric acid, myoinositol, and cystine. Conclusions: Herein, we unveil novel immunological and metabolomic features associated with COVID-19 severity and prognosis. Our models encompass the interplay among innate and adaptive immunity, inflammation-induced muscle atrophy and hypoxia as the main drivers of COVID-19 severity.

An essential, kinetoplastid-specific GDP-Fuc: ß-D-Gal α-1,2-fucosyltransferase is located in the mitochondrion of Trypanosoma brucei.

Fucose is a common component of eukaryotic cell-surface glycoconjugates, generally added by Golgi-resident fucosyltransferases. Whereas fucosylated glycoconjugates are rare in kinetoplastids, the biosynthesis of the nucleotide sugar GDP-Fuc has been shown to be essential in Trypanosoma brucei. Here we show that the single identifiable T. brucei fucosyltransferase (TbFUT1) is a GDP-Fuc: ß-D-galactose α-1,2-fucosyltransferase with an apparent preference for a Galß1,3GlcNAcß1-O-R acceptor motif. Conditional null mutants of TbFUT1 demonstrated that it is essential for both the mammalian-infective bloodstream form and the insect vector-dwelling procyclic form. Unexpectedly, TbFUT1 was localized in the mitochondrion of T. brucei and found to be required for mitochondrial function in bloodstream form trypanosomes. Finally, the TbFUT1 gene was able to complement a Leishmania major mutant lacking the homologous fucosyltransferase gene (Guo et al., 2021). Together these results suggest that kinetoplastids possess an unusual, conserved and essential mitochondrial fucosyltransferase activity that may have therapeutic potential across trypanosomatids.

An annotated checklist of ladybeetle species (Coleoptera, Coccinellidae) of Portugal, including the Azores and Madeira Archipelagos.

A comprehensive annotated checklist of the ladybeetle species of Portugal, including the Azores and Madeira archipelagos, is presented. The Coccinellidae fauna comprises a total of 101 species: 83 from the Mainland, 39 from Madeira, and 32 from the Azores. The listed species are distributed among 2 sub-families and 13 tribes: within the subfamily Microweiseinae, Madeirodulini (1 species), Serangiini (2 species), and within the subfamily Coccinellinae, Azyini (1 species), Chilocorini (4 species), Coccidulini (7 species), Coccinellini (30 species), Epilachnini (4 species), Hyperaspidini (7 species), Noviini (2 species), Platynaspini (1 species), Scymnini (37 species), Stethorini (3 species), and Sticholotidini (2 species). The Portuguese fauna comprises 10 exotic species: 5 present in the Mainland, 7 in Madeira, and 6 in the Azores. Harmoniaaxyridis (Pallas, 1773) from Madeira, Propyleaquatuordecimpunctata (Linnaeus, 1758) from the Azores, Delphastuscatalinae (Horn, 1895) from the Azores and Madeira, Nephus (Geminosipho) reunioni (Fürsch, 1974) and Nephus (Nephus) voeltzkowi Weise, 1910 from Madeira and Microserangium sp. from the Mainland, are reported for the first time. Some species are considered doubtful records, as explained in the text. These results were obtained by compiling information on the available literature regarding ladybeetle species on the Portuguese mainland and insular territories, and original data.

Impact of the Invasive Argentine Ant in Citrus Agroecosystems: Effects on the Diversity and Frequency of Native Ant Species Foraging on Tree Canopy.

The invasion of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera, Formicidae) can alter the entire ecosystem with serious impacts on the native community structure (e.g., ant diversity) and processes (e.g., trophic interactions) leading to biodiversity loss and pest outbreaks. Most studies addressing these impacts have been conducted in natural or semi-natural areas, few are those conducted in agricultural ecosystems, such as citrus orchards. These are dominant agricultural ecosystems in Mediterranean landscapes. Furthermore, most studies have been conducted in a short span, not evidencing seasonal fluctuations. In this work, we assessed the ecological impact of the Argentine ant on the native ant communities in citrus orchards, in the region of Algarve, southern Portugal. By using principal response curve, we compared seasonal variation on ant assemblages in invaded and uninvaded citrus orchards foraging on tree canopy from a two-year sampling. The Argentine ant had a marked negative impact on the native ant community foraging on citrus canopy. In the uninvaded orchards, the native ant community had a rich assemblage composed of 16 ant species, in its majority (72%) controlled by the dominant species Lasius grandis Forel, Tapinoma nigerrimum (Nylander) and/or Pheidole pallidula (Nylander). In the invaded orchards, the native ant community was poorer and highly modified, mostly dominated by the Argentine ant (80%). Apparently, the only native ant species not affected by the presence of the Argentine ant was Plagiolepis pygmaea (Latreille). A significant negative effect was found between the proportion of infested trees by L. humile and the number of native ant species per orchard. Differences in the native ant community in the invaded and uninvaded orchards persisted over seasons and years. However, negative impacts were higher in the spring and summer, and less pronounced in the autumn. We discuss implications for citrus pest management.

Proteomic Profiling Reveals the Induction of UPR in Addition to DNA Damage Response in HeLa Cells Treated With the Thiazolo[5,4-b]Quinoline Derivative D3ClP.

9-[(3-chloro)phenylamine]-2-[3-(diethylamine)propylamine]thiazolo[5,4-b]quinolone (D3ClP) is a bioisostere of N-(4-(acridin-9-ylamino)-3-methoxyphenyl)methanesulfonamide (m-AMSA) a DNA topoisomerase II inhibitor with proven cytotoxic activity and known to induce DNA damage and apoptotic cell death in K562 cells. However, recent evidence is not consistent with DNA topoisomerase II (DNA TOP2) as the primary target of D3ClP, in contrast to m-AMSA. We provide evidence of histone γH2AX phosphorylation at Ser135 in HeLa cells treated with D3ClP, a marker of DNA double strand repair through Mre11-Rad50-Nbs1 (MRN) pathway. Using two-dimensional gel electrophoresis and mass spectrometry, the upregulation of the protein GRP78, the cleavage of Cytokeratin 18, and the downregulation of prothymosine, calumenin, and the α chain of the nascent polypeptide associated complex were observed in HeLa cells treated with D3ClP. An increase in GRP78 has been related with the onset and progression of the unfolded protein response (UPR), a process aimed to reduce endoplasmic reticulum (ER) stress and protein misfolding. The IRE1-α dependent splicing of mRNA encoding X-box binding protein 1 was detected. Microtubule-associated Proteins 1A/1B, Light Chain 3-II (LC3b-II) accumulation was observed, and suggest some involvement of autophagy. The production of the pro-apoptotic protein DNA-damage-inducible protein 153 (GADD-153) was also detected. These results, are consistent with the induction of the UPR and the DNA-Damage Response in D3ClP-treated HeLa cells, and are also consistent with a concurrent apoptotic cell death. J. Cell. Biochem. 118: 1164-1173, 2017. © 2016 Wiley Periodicals, Inc.

Paternal inheritance in mealybugs (Hemiptera: Coccoidea: Pseudococcidae).

Mealybugs have a haplodiploid reproduction system, with paternal genome elimination (PGE); the males are diploid soon after fertilization, but during embryogenesis, the male paternal set of chromosomes becomes heterochromatic (HC) and therefore inactive. Previous studies have suggested that paternal genes can be passed on from mealybug males to their sons, but not necessarily by any son, to the next generation. We employed crosses between two mealybug species--Planococcus ficus (Signoret) and Planococcus citri (Risso)--and between two populations of P. ficus, which differ in their mode of pheromone attraction, in order to demonstrate paternal inheritance from males to F2 through F1 male hybrids. Two traits were monitored through three generations: mode of male pheromone attraction (pherotype) and sequences of the internal transcribed spacer 2 (ITS2) gene segment (genotype). Our results demonstrate that paternal inheritance in mealybugs can occur from males to their F2 offspring, through F1 males (paternal line). F2 backcrossed hybrid males expressed paternal pherotypes and ITS2 genotypes although their mother originated through a maternal population. Further results revealed other, hitherto unknown, aspects of inheritance in mealybugs, such as that hybridization between the two species caused absence of paternal traits in F2 hybrid females produced by F1 hybrid females. Furthermore, hybridization between the two species raised the question of whether unattracted males have any role in the interactions between P. ficus and P. citri.

Diel periodicity of pheromone release by females of Planococcus citri and Planococcus ficus and the temporal flight activity of their conspecific males.

The diel periodicity of sex pheromone release was monitored in two mealybug species, Planococcus citri and Planococcus ficus (Hemiptera; Pseudococcidae), using sequential SPME/GCMS analysis. A maximal release of 2 ng/h pheromone by 9-12-day-old P. citri females occurred 1-2 h before the beginning of photophase. The highest release of pheromone by P. ficus females was 1-2 ng/2 h of 10-20-day-old females, approximately 2 h after the beginning of photophase. Mating resulted in termination of the pheromone release in both mealybug species. The temporal flight activity of the males was monitored in rearing chambers using pheromone baited delta traps. Males of both P. citri and P. ficus displayed the same flight pattern and began flying at 06:00 hours when the light was turned on, reaching a peak during the first and second hour of the photophase. Our results suggest that other biparental mealybug species display also diel periodicities of maximal pheromone release and response. Direct evaluation of the diel periodicity of the pheromone release by the automatic sequential analysis is convenient and will be very helpful in optimizing the airborne collection and identification of other unknown mealybug pheromones and to study the calling behavior of females. Considering this behavior pattern may help to develop more effective pheromone-based management strategies against mealybugs.

Evidence for gene flow between two sympatric mealybug species (Insecta; Coccoidea; Pseudococcidae).

Occurrence of inter-species hybrids in natural populations might be evidence of gene flow between species. In the present study we found evidence of gene flow between two sympatric, genetically related scale insect species--the citrus mealybug Planococcus citri (Risso) and the vine mealybug Planococcus ficus (Signoret). These species can be distinguished by morphological, behavioral, and molecular traits. We employed the sex pheromones of the two respective species to study their different patterns of male attraction. We also used nuclear ITS2 (internal transcribed spacer 2) and mitochondrial COI (Cytochrome c oxidase sub unit 1) DNA sequences to characterize populations of the two species, in order to demonstrate the outcome of a possible gene flow between feral populations of the two species. Our results showed attraction to P. ficus pheromones of all tested populations of P. citri males but not vice versa. Furthermore, ITS2 sequences revealed the presence of 'hybrid females' among P. citri populations but not among those of P. ficus. 'hybrid females' from P. citri populations identified as P. citri females according to COI sequences. We offer two hypotheses for these results. 1) The occurrence of phenotypic and genotypic traits of P. ficus in P. citri populations may be attributed to both ancient and contemporary gene flow between their populations; and 2) we cannot rule out that an ancient sympatric speciation by which P. ficus emerged from P. citri might have led to the present situation of shared traits between these species. In light of these findings we also discuss the origin of the studied species and the importance of the pherotype phenomenon as a tool with which to study genetic relationships between congener scale insects.

Molecular evidence of polyandry in the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae).

The occurrence of polyandry in Planococcuscitri, presumed by earlier observations of mating behavior, was confirmed using microsatellite genotyping of pools of over 400 eggs resulting from controlled crosses of one female with two males. The genetic contribution of both mated males was confirmed in 13 out of 43 crosses. In three crosses it was possible to determine that only the first male fertilized the eggs, which may be due to sperm competition or unviable sperm supply. The microsatellite analysis also allowed the confirmation of aspects of the chromosomal inheritance detected previously in cytogenetic studies in Planococcuscitri, namely that only one of the alleles is transmitted by the male, indicating that the males are functionally haploid, supporting the observation of Paternal Genome Elimination (PGE) in these insects.

Male behaviors reveal multiple pherotypes within vine mealybug Planococcus ficus (Signoret) (Hemiptera; Pseudococcidae) populations.

The vine mealybug (VM) females collected in Israel produce two sex pheromone compounds: lavandulyl senecioate (LS) and (S)-lavandulyl isovalerate (LI). The males display ambiguous behavior to LI: repulsion in the vineyard and attraction of laboratory-reared males. We addressed the question of individual male behavior, i.e., do males respond to both LS and LI, or might they display a distinct response to each of the two pheromone compounds. We compared male pherotype frequencies between wild-caught and laboratory-reared populations. Then, we examined the relationship between pherotype composition and male capture rates in pheromone traps. Finally, we addressed the heredity of the pherotypes. The Israeli VM populations contain nine different male pherotypes, as defined according to the male behavior to pheromone compounds. The studied Portuguese populations included five of the nine pherotypes; none of the Portuguese males were attracted to LI. It seems that the high frequency of males that were attracted to LI is related to dense VM populations. It is hypothesized that selection for the male pherotypes, I males, those that respond to LI, occur under high-density rearing conditions. This may result from shorter development times of males and females that produce more I male pherotypes. The lower relative frequency of trapping of males in LI-baited traps than expected from the percentage determined in a Petri dish arena suggests that males that respond solely to LS (S males) are better fliers. The results also suggest that the pherotype trait is inherited by both sexes of the VM.