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At least 19 recordsLinked to original sources
PubMed1976

Studies on the phyllosphere microflora of tapioca (Manihot utilissima Pohl).

Studies on the phyllosphere microflora of tapioca (Manihot utilissima Pohl.) revealed that incidence of bacteria, fungi, and actinomycetes is indipendent of the variety, but dependent on the age. The bacteria and fungi increased with increasing age of the leaf and were more on mature leaves, whereas no such difference was noticed in the occurrence of actinomycetes. The large majority of the isolates, that were Gram-negative bacteria, was also amino acid-requiring. The chromogenic types occurred in greater abundance. The phyllosphere mycoflora consisted mainly of species of Asperigullus, Penicillium, Mucor, Curvularia, Alternaria, Helminthosporium, Fusarium, Hormicium, and Pullularia, at first three being predominant. There was no correlation between HCN content of leaves and microorganisms in the phyllosphere, Regarding the interrelationship between different groups of microorganisms in the phyllosphere, a positive correlation between fungi and actinomycetes and bacteria and actinomycetes in two (M. 4 and H. 105/44) varieties and a negative correlation for fungi and actinomycetes in one (H. 12/49) were obtained. The effect of leaf exudate and leaf, root, and tuber extracts on the germination of the conidia of three saprobic fungi, viz., Curvalaria sp., Alternaria sp., and Helminthosporium sp. was tested. While the leaf exudate and tuber extracts slightly stimulated the germination of the conidia of the fungi, the leaf extract exerted a selective inhibitory effect on the germination of the conidia of Curvalaria sp., but not on the conidia of Helminthosporium sp. and Alternaria sp.

Alternaria↗
PubMed2026

Pinpointing genomic regions conferring herbicide tolerance in cassava via genome-wide association mapping.

Cassava (Manihot esculenta Crantz) is a tropical crop of major socioeconomic importance, whose productivity can be limited by sensitivity to herbicides used for weed management. This study aimed to perform a genome-wide association study (GWAS) in 194 cassava genotypes to identify genomic regions associated with tolerance to the herbicides mesotrione, S-metolachlor, and chloransulam-methyl. The evaluations performed at 3, 6, 9, 15, and 30 days after application (DAA) were used to characterize the temporal progression of phytotoxicity. Based on this analysis, the phenotype obtained at 9 days after application (PhytoX9DAA) was selected for genome-wide association analyses because it represented the period of greatest symptom expression and the highest discrimination among genotypes. GWAS analyses were performed using de-regressed BLUPs and the MLM, MLMM, and BLINK models, incorporating kinship (K) and population structure (Q) matrices. Significant markers were detected across multiple chromosomes, and the corresponding genomic windows contained candidate genes with functional annotations related to herbicide response. The predominant functional categories included membrane transport, channel activity, signal peptide processing, protein phosphorylation, cellular signaling, and metabolic regulation. Key candidate genes included Manes.02G151900 and Manes.02G152700 (chromosome 2), associated with transmembrane transport and signal peptide processing; Manes.09G060900 (chromosome 9), associated with protein kinase activity, ATP binding, and protein phosphorylation; and Manes.15G083800 and Manes.15G084000 (chromosome 15), associated with S-adenosylmethionine-dependent methyltransferase activity, membrane-related functions, and protein phosphorylation. These genes participate in biochemical pathways involved in cellular signaling, membrane transport, and metabolic regulation that may contribute to herbicide tolerance. Overall, the results demonstrate that herbicide tolerance in cassava is a quantitative and polygenic trait governed by numerous small-effect loci. The integration of cellular signaling, metabolic regulation, and membrane transport supports the physiological resilience of the species under chemical exposure, providing valuable insights for breeding strategies and marker-assisted selection.

Genome-Wide Association Study↗
PubMed2023

Utilizing evolutionary conservation to detect deleterious mutations and improve genomic prediction in cassava.

INTRODUCTION: Cassava (Manihot esculenta) is an annual root crop which provides the major source of calories for over half a billion people around the world. Since its domestication ~10,000 years ago, cassava has been largely clonally propagated through stem cuttings. Minimal sexual recombination has led to an accumulation of deleterious mutations made evident by heavy inbreeding depression. METHODS: To locate and characterize these deleterious mutations, and to measure selection pressure across the cassava genome, we aligned 52 related Euphorbiaceae and other related species representing millions of years of evolution. With single base-pair resolution of genetic conservation, we used protein structure models, amino acid impact, and evolutionary conservation across the Euphorbiaceae to estimate evolutionary constraint. With known deleterious mutations, we aimed to improve genomic evaluations of plant performance through genomic prediction. We first tested this hypothesis through simulation utilizing multi-kernel GBLUP to predict simulated phenotypes across separate populations of cassava. RESULTS: Simulations showed a sizable increase of prediction accuracy when incorporating functional variants in the model when the trait was determined by<100 quantitative trait loci (QTL). Utilizing deleterious mutations and functional weights informed through evolutionary conservation, we saw improvements in genomic prediction accuracy that were dependent on trait and prediction. CONCLUSION: We showed the potential for using evolutionary information to track functional variation across the genome, in order to improve whole genome trait prediction. We anticipate that continued work to improve genotype accuracy and deleterious mutation assessment will lead to improved genomic assessments of cassava clones.

cassava (Manihot esculenta)↗
PubMed1978

[Peptidoglycan type and cell wall polysaccharide composition of Cellulomonas cartalyticum and some coryneform organisms (author's transl)].

Cellulomonas cartalyticum was found to contain a peptidoglycan type different from that of the other species of Cellulomonas. The diamino acid is lysin instead of ornithine and the interpeptide bridge consists of D-Asp-D-Ser. The same peptidoglycan type occurs in Corynebacterium manihot, Brevibacterium liticum and Arthrobacter luteus. These non cellulolytic organisms are most likely not closely related with Cellulomonas cartalyticum, as indicated by the very different G +C content of their DNA, although they formed a narrow cluster including C. cartalyticum when numeric taxonomical methods were applied.

Actinomycetales↗
PubMed1979

[Role of the digestive microflora and of the crystalline structure of starch in digestion and dietary efficiency in the chicken. Study of tropical tubers].

The influence of microflora in the utilization of starches, the X ray pattern which was of A or B type, was studied by balances and carcasses analysis with growing axenic or holoxenic chickens, put in isolators. Five tropical tubers were used : Manihot utilissima and Dioscorea dumetorum of A-type, Dioscorea cayenensis and alata and Canna edulis of B-type. They were introduced in isoenergetic (4,460 Kcal/g D.M.) and isoproteic (18 p. 100) diets. The A-type starches are entirely digested (95 p. 100) and the B-type are poorly digested (40-60 p. 100). The first ones induced a better growth than the second. The influence of digestive microflora changes with the two types of tubers used. With A-type starches the microflora lowered the feed intake, the growth and the energy and protein efficiency respectively--25 and--10 p. 100. When the diet included tubers with B-type starches, the low digestibility of starch and the low metabolisable energy in the diets induced poor growth and retentions. The results are discussed in relation with the starch breakdown into glucose, lactic acid and volatile fatty acids.

Animals↗
PubMed2026

A Meta-learning-driven strategy for adulteration detection in sweet potato starch and vermicelli using Raman spectroscopy.

To address the widespread adulteration of sweet potato starch and its vermicelli with cheaper starches and overcome conventional supervised learning's dependency on large labeled datasets, this study developed a few-shot discrimination method integrating Raman spectroscopy with meta-learning. We constructed a meta-learning framework using cassava- and wheat-adulterated sweet potato starch as the source domain for training, with potato-adulterated sweet potato starch and cassava-adulterated sweet potato vermicelli as two target domains for testing. Raman spectra showed high consistency between sweet potato vermicelli and its raw starch, laying the foundation for cross-domain detection. Testing yielded comprehensive classification accuracies of 95.33% and 98.00% for the two target domains, significantly outperforming SVM, RF, and CNN (max. 85.24%). This approach effectively identifies subtle starch variety differences in complex adulteration, providing novel food quality inspection solutions and verifying the feasibility of raw material-to-finished product cross-domain detection.

Ipomoea batatas↗
PubMed2026

Carboxyl group number and acidity of organic acids regulate structural reorganization and low glycemic index in cassava pyrodextrins via molecular interactions.

Transforming high-glycemic cassava starch into functional dietary fiber via pyrodextrinization is a promising way to valorize tuber crops, yet the molecular mechanisms catalyzed by organic acids with different carboxyl numbers and acidity remain unclear. This study investigates how carboxyl number and acidity of acetic acid (AA), tartaric acid (TA), and citric acid (CA) affect structural reorganization and low glycemic properties of cassava pyrodextrins. Compared with AA, TA, and CA with stronger acidity and more carboxyl groups promoted more extensive hydrolysis, transglycosylation, repolymerization, and esterification. These changes increased indigestible glycosidic linkages and the branching degree, while reducing molecular weight. Molecular docking confirmed stronger hydrogen-bonding interactions between TA/CA and starch chains. Furthermore, TA- and CA-catalyzed pyrodextrins exhibited superior anti-digestive properties with resistant starch up to 54.26% and an estimated glycemic index as low as 42.46, highlighting the critical role of carboxyl numbers and acidities in modulating the functionality of pyrodextrins.

Manihot↗
PubMed1975

High-temperature production of protein-enriched feed from cassava by fungi.

A simple, nonaseptic, low-cast process for the conversion of cassava, a starchy tropical root crop, into microbial protein for use as animal feed was sought. Screening tests culminated in the isolation of a thermotolerant, amylase-producing mold, designated I-21, which was identified as Aspergillus fumigatus. The optimum pH for protein synthesis was 3-5, but the optimum temperature was less than the desired temperature (larger than or equal to 45 C) required for a nonaseptic fermentation. A. fumigatus I-21 and its asporogenous mutant I-21A grew equally well in a medium prepared from whole cassava roots with a mean protein doubling time at 45 C and pH 3.5 of 3.5 h. In batch culture, approximately 4% carbohydrate, supplied as whole cassava, could be feremented in 20 h, giving a final yield of 24 g of dry product, containing 36.9% crude protein, per liter. The conversion of carbohydrate used to crude protein was 22.1%. When determined as amino acids, the protein content of the product, which contained cassava bark and other unfermented residues, was 27.1%. With urea as the nitrogen source, no pH control was necessary. Preliminary data indicated that medium prepared from whole cassava roots was inhibitory to the mold unless the cassava pulp was heated to 70 C immediately after being ground. Heating to 70 C was required to gelatinize the starch and permit its complete utilization.

Animal Feed↗
PubMed1979

Effects of cyanogenic agents on reproduction and neonatal development in rats.

A diet consisting of 50% gari (a form of cassava meal) was found to cause no significant biochemical and haematological changes in adult female rats. Although this diet caused a significant increase in their serum thiocyanate levels, there was no corresponding significant increase in the weight of their thyroid glands. The offspring of these rats had significantly lower birth weights and brain weights and never attained the same adult weights as those of the controls. Adult female rats fed a diet consisting entirely of raw cassava had significantly reduced haematological and biochemical indices. This diet also caused an increased incidence of cannibalism and a significant reduction in the frequency of pregnancy, the average number of the litter and the birth weights among these rats. In addition there was an increased incidence of neonatal deaths among the offspring which also had poor development, reduced brain weights and an increased tendency towards biting their litter-mates. Adult female rats fed diets containing 5 and 10 g cyanide/100 g laboratory diet survived for more than 3 months but never became pregnant. They developed enlarged thyroid glands and tumours of the large intestine. The relevance of these findings to the areas of the world where cyanogenic glycosides form the staple diet is discussed.

Animals↗
PubMed1976

The tropical amblyopia syndrome (or tropical nutritional amblyopia) in the Mid-Western State of Nigeria.

One hundred and seven patients from the Mid-Western State of Nigeria with the tropical amblyopia syndrome are reported. Ninety-five patients (88.8%) had the amblyopia syndrome mainly; twelve patients (11.2%) had amblyopia and other manifestations of the tropical ataxic neuropathy. The young, aged 10-20 years, represented by sixty-six patients (61.8%), are predominantly affected by the uncomplicated syndrome. Thirteen patients (12.1%) showed muco-cutaneous evidence of avitaminosis. Fifty patients (46.7%) had temporal pallor of the optic discs, bilaterally, another fifty (46.7%) had normal discs, two (2.8%) showed pink discs. Generalized field constriction is the common field defect, though central or centro-caecal scotoma can occur. Red/green defect was present in seven patients. It is a disease of the poor or those living on a basic monotonous diet consisting mainly of cassava (mannihot) and its derivatives. It is a significant cause of defective vision in Mid-Western Nigeria.

Adolescent↗
PubMed1977

Safety evaluation of Aspergillus fumigatus grown on cassava for use as an animal feed.

A safety evaluation of Aspergillus fumigatus I21, grown in a cassava carbohydrate and salts medium, was undertaken. Male weanling rats were fed the fungus at 20, 30 and 40% of the diet for 90 days. A control group was given soybean oil meal as the sole source of protein. Weekly determinations of the body weights and feed consumptions were made. A few days prior to termination of the feeding study, a kidney function test was undertaken on the rats. At the end of the feeding period hematology, blood biochemistry, urine analyses and histopathology studies of various tissues were carried out, and organs were weighed. Rats fed A. fumigatus I21 gained less weight than the controls, but kidney weights were increased. Increases in serum alkaline phosphatase and glutamic-oxaloacetic transaminase were not related to dose level. The blood urea nitrogen was increased for the rats fed 40% of the fungus. Rats fed 30 and 40% of the fungus I21 showed a significant drop in albumin. Deficiency in methionine or other essential amino acids through a limited feed consumption may have caused a decrease in albumin synthesis. Rats fed the highest level of the fungus showed increases in neutrophils and monocytes concomitant with decreases in lymphocytes and eosinophils which may be a response to stress. The urine analyses did not reveal any significant differences. The test rats were capable of concentrating urine adequately when deprived of water for 24 hours. No significant differences between the control and experimental groups were found by histopathological examinations.

Animal Feed↗