Absence Of Blood Meal Research Articles

Detrimental Effects of Blood Meal and Feather Meal on Tomato (Solanum lycopersicon L.) Seed Germination

There is limited information on the effect of organic fertilizers on seed germination and subsequent transplant growth. The objective of this study was to determine the effects of application rate of blood meal (BM) and feather meal (FM) fertilizers on germination of tomato seeds. Both organic fertilizers were applied as amendments to peat-based organic substrates at rates ranging from 0 to over 50 g·kg−1 N. Tomato ‘Brandywine’ seed were sown in trays. Seed germination was recorded daily until the germination percentage remained unchanged. Ammonia concentration in the substrates (Pro-Mix and Miracle-Gro) increased with increasing rate of substrate N concentration. Ammonia concentration also increased with increasing time after incorporation of BM and FM reaching maximum values (16 ppm) at day 9. Tomato seed germination was little affected at BM and FM rates lower than ≈3 g·kg−1 N (4% w/w for BM or FM), but declined above 3 g·kg−1 N reaching 0% germination rate at ≈14 g·kg−1 N for both BM and FM. Substrates pH was 5.9 in the absence of BM or FM and increased to about pH 7 with addition of low rates of BM (2.7 g·kg−1 N) and FM (2.6 g·kg−1 N). Substrate electrical conductivity (EC) increased with increasing substrate N concentration as supplied by BM and FM; FM, however, had a stronger effect on increasing EC compared with BM. In conclusion, BM and FM had inhibitory effects on tomato seed germination when applied at more than 3 g·kg−1 N (4% w/w for BM or FM). High ammonia concentration in the substrates for the first 2 weeks after incorporation of BM or FM likely caused, at least partially, inhibition of tomato seed germination. Thus, substrate mixed with BM or FM should be allowed to incubate for at least 2 weeks before planting tomato seed.

Bacterial diversity of the American sand fly Lutzomyia intermedia using high-throughput metagenomic sequencing.

BackgroundParasites of the genus Leishmania cause a broad spectrum of diseases, collectively known as leishmaniasis, in humans worldwide. American cutaneous leishmaniasis is a neglected disease transmitted by sand fly vectors including Lutzomyia intermedia, a proven vector. The female sand fly can acquire or deliver Leishmania spp. parasites while feeding on a blood meal, which is required for nutrition, egg development and survival. The microbiota composition and abundance varies by food source, life stages and physiological conditions. The sand fly microbiota can affect parasite life-cycle in the vector.MethodsWe performed a metagenomic analysis for microbiota composition and abundance in Lu. intermedia, from an endemic area in Brazil. The adult insects were collected using CDC light traps, morphologically identified, carefully sterilized, dissected under a microscope and the females separated into groups according to their physiological condition: (i) absence of blood meal (unfed = UN); (ii) presence of blood meal (blood-fed = BF); and (iii) presence of developed ovaries (gravid = GR). Then, they were processed for metagenomics with Illumina Hiseq Sequencing in order to be sequence analyzed and to obtain the taxonomic profiles of the microbiota.ResultsBacterial metagenomic analysis revealed differences in microbiota composition based upon the distinct physiological stages of the adult insect. Sequence identification revealed two phyla (Proteobacteria and Actinobacteria), 11 families and 15 genera; 87 % of the bacteria were Gram-negative, while only one family and two genera were identified as Gram-positive. The genera Ochrobactrum, Bradyrhizobium and Pseudomonas were found across all of the groups.ConclusionsThe metagenomic analysis revealed that the microbiota of the Lu. intermedia female sand flies are distinct under specific physiological conditions and consist of 15 bacterial genera. The Ochrobactrum, Bradyrhizobium and Pseudomonas were the common genera. Our results detailing the constituents of Lu. intermedia native microbiota contribute to the knowledge regarding the bacterial community in an important sand fly vector and allow for further studies to better understand how the microbiota interacts with vectors of human parasites and to develop tools for biological control.