Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The objective of this study was to evaluate the antibacterial and antimycobacterial potential of the by-products of white shrimp (Litopenaeus vannamei). Sonora, México is the second shrimp producer state. The following extracts were obtained: exoskeleton hexanic, methanolic and acqueous extracts (ExHex, ExMe, ExAc); and cephalothorax hexanic, acetonic and methanolic extracts (CeHex, CeAce, CeMe). Antibacterial effect was determined by the broth microdilution method against Gram-positive bacteria: Enterococcus faecalis American Type Culture Collection (ATCC) 51299, Staphylococcus aureus ATCC 25293, and Staphylococcus epidermidis; Gram-negative bacteria: Escherichia coli ATCC 25922, Klebsiella pneumoniae, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium; and Mycobacterium bovis bacillus Calmette-Guérin (M. bovis BCG) Danish strain. CeHex resulted active against all Gram-positive and Gram-negative bacteria (MIC50= 400 ug mL-1) and against M. bovis BCG (MIC100= 250 ug mL-1). Gas chromatography (GC) of CeHex identified oleic, linoleic, palmitic, stearic, behenic, palmitoleic and linolenic fatty acids. The strong antibacterial activity of CeHex and the identification of its main chemical constituents justify further studies on the clinical applications of this marine by-product.

In this work, the potential of water hyacinth (Eichhornia crassipes) and pecan nutshell (Carya illinoinensis) as a source of lignin was investigated. The lignin extraction was carried out using an organosolv procedure and was characterized by infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The antioxidant activity was determined through the stabilization of the free radicals DPPH and ABTS. The results showed higher lignin content and extraction performance in pecan nutshells. The infrared spectrum revealed typical bands of the main functional groups; phenolic –OH groups, C – H3 methyl groups, and O–CH3 methoxyl which are part of the aromatic ring of lignin. The water hyacinth lignin (LLA) showed high resistance to thermal degradation which places it as an interesting component for the development of phenolic resins and flame retardants. The lignin extracted from pecan nutshell (LCN) showed a high percentage of inhibition against DPPH and ABTS radicals when it was solubilized in ethanol, methanol, and in ethanol-methanol mixtures (50:50 v/v). The high antioxidant activity of LCN indicates that this type of lignin may have applications in the food and pharmaceutical industries.

Recurrent droughts and competition for water are the main threats to the development of corn (Zea mays L.) in agricultural areas of Sinaloa, Mexico. Sinaloa is the main state in national corn production, but an excessive amount of water is applied in gravity irrigation, a situation that should decrease without reducing crop yields. There are many ways to improve the humidity conditions in the soils, one of them is minimum tillage and conservation, synthetic gels, which allow the retention of humidity in the soils. But in conditions of low availability and high water competition, strategies are required to improve water retention, organic additives are an alternative due to their high moisture retention. This research aims to know the effect that different doses of an organic additive have, in corn cultivation (cost-production), during the winter cycle 2018-2019 in Guasave, Sinaloa, Mexico. An experimental design of 3 divided plots was developed, plot 1 (treatment 1), plot 2 (treatment 2), plot 3 (treatment 3). A positive effect was found in the increase of soil moisture retention and a greater production of corn grain as the dose of the organic additive increased. Keywords: Organic improver, corn planting, water expenditure, corn production.  

Raw cow's milk is widely used as a raw material to elaborate artisanal products; however, it is necessary to analyze its quality before its transformation into the final product. The objective of this study was to evaluate the quality of raw milk from Tepatitlán de Morelos, Jalisco, used for the production of artisanal products concerning the physicochemical and microbiological limits established in Mexican standards. The factors studied in this study were the type of milking and the milk treatment. The quality analysis of the samples collected was carried out according to Mexican standards. Regarding microbiological quality, the results of somatic cells, mesophilic bacteria, and total coliform organisms showed that most samples did not comply with the limits established in Mexican regulations. In contrast, the results of the physicochemical analysis of the milk showed protein, fat, lactose, and non-fat solids content within the specifications established by regulations. The results reflect the poor microbiological quality of the milk used to elaborate artisanal products; this is the consequence of poor hygiene practices during milking, storage, and transportation.

The water needs in crops are naturally satisfied by rains, when it is insufficient, gravity irrigation is applied, which requires knowing the soil’s moisture behavior. There are methods to measure and estimate humidity: the TDR- 300 method calculates humidity in real time and the Green and Ampt model that estimates the irrigation sheet (cm)in the laboratory. The Green and Ampt method knows the physical parameters of the 12 textural classes of soils, but does not know physical parameters by mixing soil with organic additives. In this investigation, numerical values of hydrodynamic parameters were calculated in soil mixed with organic additive, using TDR-300 equipment in three 30-mrows, with measurements every 5 m, an experimental design of 3 x 3, with T1-control treatments (soil normal), T2 (Soil + 25% additive) and T3 (soil + 50% additive), applying gravity irrigation, and compare estimates with the Green and Ampt  model. Using Green and Ampt methodology, initial and finalgravimetric humidity, water advance time, recession time and opportunity were calculated. The higher the additive content, the retention increased. The estimates made by the Green and Ampt method were similar with the TDR method.

Safflower and cereals sowing as an alternative to oat allow to increase the forage potential in late sowings during fall-winter season. The objective of the study was to compare the forage potential and nutritive value of cereals and safflower with those observed in oat late sowings during fall-winter season. The study was conducted during the fall-winter season of 2017-2018 and 2018-2019 in Matamoros, Coahuila, Mexico. Cultivars of oat, barley, wheat, triticale and safflower with or without spines were evaluated. A randomized complete block design with four replications was used. Forage nutritive value, dry matter (DM) and nutrients yields were determined. Late sowing of barley and wheat increased the forage potential with or without incidence of foliar disease in oat. The increments reached from 26.3 % to 39 % in DM yields, 34.8% in Crude protein yields, 34.2 % in net energy for lactation yields and 29.4 % to 34.8 % in digestible DM yield. The species triticale, wheat, barley and spineless safflower also were good alternatives, but only when dry forage yields were reduced by foliar diseases. The forage potential may be increased using alternative species to oat in late sowings of fall-winter season.

Currently, public health concerns are bacterial resistance to multiple antibiotics. This has driven the search for natural products with therapeutic effects. In this sense, it has been found that Eichhornia crassipes, derived from its phytochemical composition, possesses biological properties. The present study focuses on determining chemical-proximal and phytochemical composition of E. crassipes extracts obtained by maceration and Soxhlet and evaluating their bacteriostatical potential. The chemical-proximal composition indicated that leaf fraction presents a high concentration of protein (32.67 ± 0.25%) and holocellulose (65.34 ± 0.06%); phytochemical analysis of different plant fractions (leaf (L), bulb (b) and leaf + bulb (L+B)) indicates the presence of flavonoids, phenols, tannins and saponins, mainly. Furthermore, aqueous extracts presented the highest concentration of phytochemical compounds. Ethanolic extract obtained by maceration of L+B fraction (18.53 mm) and aqueous extract of L fraction obtained by Soxhlet (18.40 mm) showed more significant inhibition against Staphylococcus aureus. In contrast, the ethanolic and aqueous extracts obtained by the Soxhlet method (11.97, 11.93 mm, respectively) of L fraction showed the highest inhibition against Salmonella sp.

The objective of the study was to evaluate three wild plant growth promoter rhizobacteria (PGPR) (Bacillus sp, B. cereus and B. licheniformis), inoculated individually and in combination on the agronomic properties and mineral quality of marigold crop on open field. Eight treatments were compared: T0= control, T1= Bacillus sp., T2= B. cereus, T3= B. licheniformis, T4=Bacillus sp. + B. cereus, T5= Bacillus sp. + B. licheniformis, T6= B. cereus + B. licheniformis, T7= Bacillus sp. + B. cereus + B. licheniformis, with Steiner nutrient solution without Calcium. The experiment was established in randomized complete blocks with three repetitions per treatment. The results showed that the fresh and dry root biomass increased with the application of the T6 treatment, fresh and dry foliage biomass presented higher values in T5, same treatment that increased total carotenoids (847.01 μg·g-1). Meanwhile the minerals, calcium was concentrated in leaves, in T2 and T1, magnesium in leaves in T7, potassium in stem in T5, phosphorus in petals in T5, nitrogen in leaves, in T1 and T2. Bacillus application is an alternative to replace calcium fertilizers, which could help mitigate the negative effects of chemical fertilization.

In agriculture, water efficiency and balance of supply and demand in crops are essentials. The lack of knowledge in the infiltration process in gravity irrigation increases in high-demand crops such as corn, sorghum and beans. Knowing the moisture retention in agricultural soils is important to satisfy the demand in agriculture. The purpose of this research was to study the hydrodynamic movement of water in eight treatments, mixed homogeneously, with organic additives and agricultural soil (clay loam), analyzing benefits in gravity irrigation (irrigation interval). Infiltration (F) was analyzed with the Green and Ampt model; Direct and indirect physical properties were evaluated, such as the volumetric water content at saturation (θS) and capillary pressure against wetting (ψf), humidity tension curve, the second parameter applying the Brooks and Corey method, and hydraulic conductivity ( Ks). The results are variable in relation to the control, organic improvers increased moisture retention by 30% and the irrigation interval increased by six days. The increase in moisture retention and accumulated infiltration, were obtained with organic material (T2) and organic material (T7), and obtained in corn harvest residues.  

Mexico is in the tenth place in worldwide tomatoproduction. The Comarca Lagunera has an important role in exports, mainly to the United States of America and allocated an area for cultivation of 984 ha under shade mesh with a production of 138,036 t. Due to the economic and social importance in the region, the objective of this study was to determine the productivity indicators of water, soil, labor, and capital, which will support the producer to make better decisions. To carry out the study, five production units under shade mesh were selected through systematic sampling, which occupied 50 % of the total planted area, and the necessary information was obtained through a survey. It was found that the average yield value was 11.9 kg of tomato per square meter; 54.3 kg of tomato per cubic meter of water, and 61.9 and 99.7 pesos for the net income obtained per square meter of surface and cubic meter of water, respectively. The highest values were recorded by the largest production units, concluding that this behavior is due to the greater economy of scale and greater care with which the crop is managed.