SUMMARY: In the present study, the diagnostic value ofTrypanosoma cruzirecombinant protein (Tc24) was examined. Although antibodies against Tc24 were detected during natural and experimentalT. cruziinfections, specificity studies revealed that sera fromT. rangeli-infected mice also recognized to some extent Tc24 protein. In addition, sera from Tc24-immunized mice reacted against a 21 kDa polypeptide inT. rangeliextracts. Detailed analysis of the antibody response against 20—40 peptide localized in the Tc24 amino-terminal domain suggests that this sequence is not expressed byT. rangeli21 kDa antigen. Therefore, the PCR reaction using oligonucleotides corresponding to a 20–26 peptide clearly demonstrated the specificity of the oligoprobes forT. cruziidentification. Positive signals were also found when using blood samples fromT. cruzi-infected mice. Taken together, these results suggest that the PCR-based 20–26 assay may be useful in the specific diagnosis of Chagas' disease.

Algeria is one of the wealthiest countries in terms of hydrothermal sources, with more than two hundred hot springs. However, diverse and little-described microbial communities colonize these habitats, making them an intriguing research subject. This work reports the isolation of bacteria from two hot springs water samples in northeastern Algeria, evaluating their enzymatic activities and effect on plant pathogens. Out of the obtained 72 bacterial isolates and based on the 16S rRNA gene sequence analysis, the strain HGR5 belonging to Bacillus halotolerans had the most interesting activity profile. Interestingly, HGR5 was substantially active against Fusarium graminearum, Phytophthora infestans, and Alternaria alternata. Furthermore, this strain presented a high ability to degrade casein, Tween 80, starch, chitin, cellulose, and xylan. The genome sequence of HGR5 allowed taxonomic validation and screening of specific genetic traits, determining its antagonistic and enzymatic activities. Genome mining revealed that strain HGR5 encloses several secondary metabolite biosynthetic gene clusters (SM-BGCs) involved in metabolite production with antimicrobial properties. Thus, antimicrobial metabolites included bacillaene, fengycin, laterocidine, bacilysin, subtilosin, bacillibactin, surfactin, myxovirescin, dumulmycin, and elansolid A1. HGR5 strain genome was also mined for CAZymes associated with antifungal activity. Finally, the HGR5 strain exhibited the capacity to degrade polycaprolactone (PCL), a model

Bacillus sp. RTS11, a xylanolytic strain, was isolated from the Algerian desert rocks. Genetic analysis revealed a remarkable 98.69% similarity to Bacillus pumilus. We harnessed optimization techniques, including Plackett-Burman screening and Box-Behnken optimization design, to amplify xylanase production and activity. The outcome of these efforts was an optimized medium that yielded an impressive xylanase production titer of 448.89 U, a threefold increase compared to the non-optimized medium (146 U). The Purification of xylanase was achieved through the three-phase partitioning technique, employing t-butanol and various chromatographic methods. Notably, anion exchange chromatography led to isolating a highly pure enzyme with a molecular weight of 60 kDa. The xylanase exhibited its peak activity at a temperature of 60°C and a pH of 9.0. When applied to pulp pretreatment, 20 U/g of xylanase demonstrated a substantial increase in the release of phenolic and chromophore compounds while reducing sugar content in the pulp. Furthermore, this versatile xylanase shows its ability to efficiently hydrolyze a variety of agro-industrial residues, including wheat bran, corn and grape waste, wheat straw, and sugarcane bagasse. These findings underscore the significant potential of this xylanase enzyme in biobleaching processes and the utilization of agro-industrial waste, opening up exciting avenues for sustainable and environmentally friendly industrial applications.

Grapevine rupestris stem pitting-associated virus (GRSPaV; Foveavirus rupestris, Betaflexiviridae) is the most widespread grapevine virus in most viticulture regions, and this virus has high genetic variability. Genetic diversity of GRSPaV in Algeria was examined, based on the complete capsid protein (CP) gene. Similarity proportions between the CP sequences varied from 76% to 99%. The complete coding sequence of Algerian GRSPaV isolate ALG99 (8,646 nt) was determined using high-throughput sequencing and bioinformatic analyses. Algerian GRSPaV isolates clustered into four groups, with most sequences in groups III and IV. This research is the first to determine the genetic variability of GRSPaV in Algeria.

Prevalence and genetic diversity of Grapevine fanleaf virus (Nepovirus foliumflabelli, GFLV) were determined in vineyards and grape varieties in Algeria. Samples (414) from different cultivars and viticulture areas were screened using DAS-ELISA and partially confirmed by RT-PCR, revealing 21% infection incidence. In Ahmer Bou Amer the greatest incidence of infection was recorded (61%). Some vines, confirmed to be GFLV-infected, had characteristic symptoms of leaf yellowing, chloroses, and mosaic patterns, reducing vine vigour and fruit quality. High throughput sequencing and bioinformatics analyses of a single GFLV-infected accession obtained a nearly complete grapevine fanleaf virus RNA1 consensus sequence of 5,979 nt, and an RNA2 with complete consensus sequence of 3,711 nt. Grapevine yellow speckle viroid, Hop stunt viroid and other viruses were also identified in the ‘background’ virome. Phylogenetic analyses of an amplified fragment of the GFLV coat protein gene from some of the accessions indicated close genetic relationships between Algerian and Russian/United States of America GFLV isolates, suggesting potential shared origins or transmission pathways. These results emphasize the need for implementing strict phytosanitary measures (e.g. use of virus-free planting material) to mitigate GFLV spread and its detrimental effects on grapevine production in Algeria.

From sand in the Algerian Sahara, an isolated strain of Bacillus called Bacillus sp. SRIT8 showed little chitinase activity when grown in a minimal medium supplemented with chitin (2.36 U). Using Plackett-Burman and Box-Behnken statistical plans, we could maximize chitinase synthesis, which led to a notable increase in this enzymatic activity (112 U). The purification of the resulting enzyme involved three steps: ammonium sulfate precipitation, molecular exclusion chromatography, and anion exchange chromatography. This process yielded a specific activity of 5437.14 U/mg with a purification yield of 22.44%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis examination revealed a protein band of about 31 kDa, and optimum enzyme activity was found at pH 5 and 40 °C. Enzyme activity was boosted by Ca+2, Na+, and Mn+2 ions but was suppressed by Hg+2 ions. The purified enzyme inhibited the growth of the plant pathogen Fusarium graminearum on wheat in both in vitro tests. So, it might prevent fungal infections in wheat throughout the germination process. The enzyme was also effective as a bioinsecticide, killing up to 52% of the larvae of Sitophilus granarius Linnaeus, an insect pest of stored grain. Our chitinases capacity to hydrolyze fungus cell walls as well as insect cuticles can be utilised as biological control agent.