The role of B-cells in immunity against adult Strongyloides venezuelensis

BACKGROUND: Strongyloides venezuelensis has been used as a tool and model for strongyloidiasis research. Elimination of S. venezuelensis adult worms from mice has been particularly associated with proliferation and activation of intestinal mast cells and eosinophils. To date, the role of B-cells in the protective mechanism against adult Strongyloides infection in experimental animals has not been reported in the literature. Therefore, the present study was carried to investigate the role of B-lymphocytes in immunity against adult S. venezuelensis infection using mice with a targeted deletion of the JH locus. METHODS: JHD knockout mice with its wild-type Balb/c mice were infected by intra-duodenal implantation of adult S. venezuelensis. Fecal egg count, intestinal worm recovery, mucosal mast cells and eosinophils were counted. RESULTS: At day 11 post infection, parasites in wild-type mice stopped egg laying, while in JHD knockout mice parasites continued to excrete eggs until the end of the observation period, day 107. The higher number of parasite eggs expelled in the feces of JHD knockout infected mice was a consequence of higher worm burdens, which established in the small intestine of these animals. On the other hand worm fecundity was comparable in both groups of mice. Both B-cell-deficient mice and wild-type mice, showed an influx of mucosal mast cells and eosinophils. The absolute numbers in JHD knockout mice were lower than those seen in wild-type mice at day 11, but not to a level of significance. JHD knockout mice could not recover from infection despite the recruitment of both types of cells. CONCLUSION: Our findings highlight a role of B cells in mucosal immunity against invasion of adult S. venezuelensis and in its expulsion. Therefore, we conclude that B-cells together with mucosal mast cells and eosinophils, contribute to immunity against adult S. venezuelensis by mechanism(s) to be investigated

Comparative Genetic Diversity Assessment and Marker–Trait Association Using Two DNA Marker Systems in Rice (<i>Oryza sativa</i> L.)

In this paper, the genetic diversities of 12 rice genotypes (Oryza sativa L.), representing Indica, Japonica, and Indica–Japonica varieties, were assessed using twelve ISSR and five SSR markers. In addition, the rice genotypes were evaluated for 11 agro-morphological traits in a two-year trial. Association mapping was performed to detect any association between the DNA markers and the agro-morphological traits. An association analysis was conducted considering the relative kinship among the genotypes and accounting for the population structure using the unified mixed-model approach to avoid possible false-positive associations. Seventy-three alleles were collectively produced by ISSRs and SSRs, with an average of 6.3 and 2.8 alleles per locus, respectively. Both marker systems were informative, and the average polymorphism information content (PIC) was 0.222 and 0.352 for ISSRs and SSRs, respectively. The average expected heterozygosity (Hexp) was 0.264 for ISSRs compared to 0.457 for SSRs. After using the false discovery rate (FDR) method, the association analysis revealed a total of 12 significant marker–trait associations with six agro-morphological traits, including the no. of unfiled grains panicle−1, panicle length, panicle weight, the no. of panicles plant−1, the no. of tillers plant−1, and 1000-grain weight. ISSRs showed seven significant associations with five markers, while SSRs showed three significant associations with three markers. The phenotypic variance (R2) explained by each marker ranged between 29.2% for the ISSR marker HB11 (associated with 1000-grain weight) and 49.3% for the ISSR marker HB8 (associated with the no. of tillers plant−1). The identified marker–trait associations reported herein may improve the expected gain of future molecular-based rice-breeding programs, particularly those designed for improving grain-related or harvest-related traits

Comparative Genetic Diversity Assessment and Marker&ndash;Trait Association Using Two DNA Marker Systems in Rice (Oryza sativa L.)

In this paper, the genetic diversities of 12 rice genotypes (Oryza sativa L.), representing Indica, Japonica, and Indica&ndash;Japonica varieties, were assessed using twelve ISSR and five SSR markers. In addition, the rice genotypes were evaluated for 11 agro-morphological traits in a two-year trial. Association mapping was performed to detect any association between the DNA markers and the agro-morphological traits. An association analysis was conducted considering the relative kinship among the genotypes and accounting for the population structure using the unified mixed-model approach to avoid possible false-positive associations. Seventy-three alleles were collectively produced by ISSRs and SSRs, with an average of 6.3 and 2.8 alleles per locus, respectively. Both marker systems were informative, and the average polymorphism information content (PIC) was 0.222 and 0.352 for ISSRs and SSRs, respectively. The average expected heterozygosity (Hexp) was 0.264 for ISSRs compared to 0.457 for SSRs. After using the false discovery rate (FDR) method, the association analysis revealed a total of 12 significant marker&ndash;trait associations with six agro-morphological traits, including the no. of unfiled grains panicle&minus;1, panicle length, panicle weight, the no. of panicles plant&minus;1, the no. of tillers plant&minus;1, and 1000-grain weight. ISSRs showed seven significant associations with five markers, while SSRs showed three significant associations with three markers. The phenotypic variance (R2) explained by each marker ranged between 29.2% for the ISSR marker HB11 (associated with 1000-grain weight) and 49.3% for the ISSR marker HB8 (associated with the no. of tillers plant&minus;1). The identified marker&ndash;trait associations reported herein may improve the expected gain of future molecular-based rice-breeding programs, particularly those designed for improving grain-related or harvest-related traits

Geochemical and Isotopic Evidence of Groundwater Salinization Processes in El Dabaa Area, Northwestern Coast, Egypt

El Dabaa city is located along the northwestern coast ridge zone of Egypt, where the groundwater is the major water source for drinking, domestic, and agricultural purposes. The groundwater salinity increased over the last decades, therefore, geochemical techniques and environmental isotopes have been utilized to identify the main groundwater recharge and salinization sources. The study area comprises two main groundwater aquifers: the porous oolitic Pleistocene and the fractured limestone Miocene aquifers. The groundwater salinity of the Pleistocene aquifer ranges from 751 to 27,870 mg/L, with an average value of 6006 mg/L. The salinity of the Miocene aquifer ranges from 3645 to 41,357 mg/L, with an average value of 11,897 mg/L. Fresh and brackish groundwater have been recorded in the shallow hand-dug wells, while saline groundwater has been found in deeper wells close to the shoreline. Groundwater samples have been categorized into two distinct groups according to the salinity ranges, hydrochemical ion ratios, and stable isotopic content. Group I is composed of groundwater with salinity less than 10,000 mg/L, and depleted stable isotopic content (&#8722;5.64 &lt; &#948;18O &lt; &#8722;2.45; &#8722;23.5 &lt; &#948;2H &lt; &#8722;0.02), while Group II contains groundwater with salinity values above 10,000 mg/L and relatively enriched stable isotopic content (&#8722;1.86 &lt; &#948;18O &lt; &#8722;0.48; &#8722;10.3 &lt; &#948;2H &lt; &#8722;2.0). The weight mass balance mixing model shows that Group I falls close to the rain and/or water extract samples, indicating meteoric water origin that has evolved due to leaching and dissolution processes. Group II is mostly located between the rainwater and the seawater samples, revealing mixing with water of marine origin due to groundwater overexploitation. The estimated seawater mixing index (SMI) of groundwater samples of Group II is greater than one, which confirms mixing with seawater. The water-rock reaction NETPATH (geochemical groundwater reaction and mixing code) model scenarios representing Group I suggests that gypsum, dolomite, and halite are dissolved, while calcite is formed with a slight influence from evaporation processes. Six mixing models representing Group II are used to investigate seawater mixing scenarios. The models suggest that illite and dolomite are dissolved, while calcite and gypsum are precipitated with a seawater mixing ratios ranging from 28% to 98%. In conclusion, due to the scarcity of annual groundwater recharge in the El Dabaa area, groundwater withdrawal should be well managed to avoid groundwater salinization and further seawater intrusion

Subtyping of Blastocystis sp. isolated from symptomatic and asymptomatic individuals in Makkah, Saudi Arabia

Abstract Background Blastocystis is a group of cosmopolitan gastrointestinal parasite of humans and a wide variety of animals. These anaerobic protozoans include more than 17 specific small-subunit ribosomal RNA subtypes, of which nine are found in humans with a variable geographical distribution. Until now, no study has described the Blastocystis subtypes present in Saudi Arabia. Methods In total, 1,262 faecal samples were collected from patients with gastrointestinal complaints and asymptomatic individuals visiting two major hospitals. All samples were analysed by F1/R1 diagnostic PCR, microscopy and culture methods. The subtypes of Blastocystis sp. isolates were determined by the sequenced-tagged site (STS)-based method. Results One-hundred-thirty-three positive cases were detected by F1/R1 diagnostic PCR, of which 122 were also positive by the culture method and 83 by direct microscopy. The sensitivities of direct microscopy and the culture method were 62% and 92%, respectively. Subtype (ST3) was the most prevalent (80.5%), followed by ST1 (14.5%) and ST2 (5%). ST4, ST5, ST6 and ST7 were not detected in this study. ST3 infections were significantly predominant (P < 0.05) among symptomatic patients. Conclusions To our knowledge, this study provides the first run-through information on Blastocystis sp. epidemiology in Makkah city, revealing a rather moderate prevalence of 10.5% and the presence of three subtypes, ST1, ST2, and ST3. ST3 was the most predominant, particularly among symptomatic patients

Genetic structure of some candidate genes of repeat breeder syndrome in Egyptian buffaloes

Abstract Background This study aimed to explore the association between polymorphisms in three genes: leptin (LEP), leptin receptor (LEPR), and BMP4, and incidence of repeat breeding in Egyptian buffaloes. Methods DNA was extracted from 160 female buffaloes, involving 108 fertile and 52 repeat breeders. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Sequence analysis and alignment were performed by employing NCBI/BLAST/blastn suite, to identify SNPs among different patterns and alleles. We utilized PredictSNP software to predict the non-synonymous SNPs influences on protein function. Moreover, the conservation score of the amino acids within the target proteins was computed by ConSurf server. Results The genotyping results showed that LEP and BMP4 genes were monomorphic (CC, GG) in all tested fertile and repeat breeder buffaloes. Leptin gene sequencing showed a non-synonymous C73T SNP, replacing R to C at position 25 within the leptin polypeptide (position 4 in the mature form; R4C) which is a neutral mutation, not affecting function or structure of LEP protein. For LEPR, one synonymous SNP (T102C) and two non-synonymous SNPs (A106G and C146A), triggering V967A and G954C replacements, respectively in LEPR protein. Moreover, they are neutral mutations. Sequencing results of BMP4 showed HinfI restriction site indicate fixed GG genotype (CC genotype in the anti-sense strand) in all sequenced samples. No SNPs were observed within the amplified region. Conclusion Genotyping and sequencing results of the surveyed three genes revealed that there is no association between these genes mutations and the incidence of repeat breeding in Egyptian buffaloes