Armando J. Martínez

Allometry of Prosopis glandulosa var. torreyana along a topographic gradient in the Chihuahuan desert

Abstract The allometric relationships of trees in temperate and tropical forests are relatively well known, but not those of woody shrubs or transitional (shrub/tree) life forms. We explored the transition of Prosopis glandulosa var. torreyana from tree to shrub along a semi-arid topographic sequence comprising of six landforms (hillslope, footslope, upper and lower bajada, playa and dune) with varying soil texture and water availability. In each landform, we measured P. glandulosa shoot pre-dawn water potentials (Ψ) in one ‘dry’ and one ‘wet’ year. We also measured plant height, widest basal stem diameter, crown area and number of basal branches. Total basal stem area was calculated. We used simple (Model II linear regression) and expanded (incorporating an asymptote to height or crown area) allometry models to compare height with widest basal stem diameter and crown area with total basal stem area. There were significant correlations between maximum plant size and inter-year Ψ means suggesting that soil water availability decreased down the topographical sequence. The height asymptote was statistically significant in all landforms and lower toward finer-textured soils. On the other hand, crown area was a linear function of total basal stem area and was also site specific. Our results suggest that more basal branches are produced as plant height decreases in more stressful environments, effectively increasing crown area with a minimum investment in supporting tissues. The polymorphic characteristics of Prosopis may partly explain their occurrence in many arid and semi-arid environments. Nomenclature: Correll & Johnston (1970); for families: Anon. (1998).

Synchronization of PER1 protein in parabrachial nucleus in a natural model of food anticipatory activity

Rabbit pups represent a natural model of food anticipatory activity (FAA). FAA is the behavioral output of a putative food entrainable oscillator (FEO). It had been suggested that the FEO is comprised of a distributed system of clocks that work in concert in response to gastrointestinal input by food. Scheduled food intake synchronizes several nuclei in the brain, and the hypothalamus has received particular attention. On the contrary, brainstem nuclei, despite being among the brain structures to first receive food cues, have been scarcely studied. Here we analysed by immunohistochemistry possible oscillation of FOS and PER1 proteins through a complete 24‐h cycle in the dorsal vagal complex (DVC) and parabrachial nucleus (PBN) of 7–8‐day‐old rabbit pups scheduled to nurse during the night (02:00 h) or day (10:00 h), and also in fasted subjects to explore the possible persistence of oscillations. We found a clear induction of FOS that peaks 1.5 h after nursing in all nuclei studied. PER1 was only synchronized in the PBN, reaching highest values 12 h after nursing. Only PER1 oscillations persisted, with a shift, in fasted subjects. We conclude that the DVC nuclei are probably more related to the transmission of food cues to other brain regions, but that the PBN participates in the integration of information essential for FAA. Our results support previous findings suggesting that the DVC nuclei, but not PBN, are not essential for FAA. We suggest that PBN is a key component of the proposed distributed system of clocks involved in FAA.

Burnout en estudiantes de pregrado de medicina y su relación con variables de personalidad

Resumen El objetivo de esta investigacion fue analizar la asociacion entre autoeficacia percibida, personalidad resistente, locus de control, percepcion de estres y sindrome de Burnout en 40 estudiantes de medicina de pregrado. El analisis de los datos se efectuo considerando estadistica descriptiva y tecnicas exploratorias multivariadas. Los resultados muestran la pertinencia que puede tener la personalidad resistente en la atenuacion del estres cronico al asociarse negativamente con el sindrome de Burnout y agruparse dentro de los componentes que explicaban mayor variacion en la combinacion lineal de variables en comparacion con la autoeficacia y el locus de control. Se confirma la necesidad de reforzar la formacion de los estudiantes de medicina a traves del establecimiento de recursos de afrontamiento ante el estres y formacion de una personalidad resistente, ya que los datos muestran niveles altos en percepcion de estres y sindrome de Burnout a seis meses de estar realizando el internado. Palabras clave: personalidad resistente, Burnout, estudiantes de medicina de pregrado y estudio descriptivo.

Organochlorine Pesticide Level Differences Among Female Inhabitants from Veracruz, Puebla and Tabasco, Mexico

Organochlorine pesticides have been used in Mexico in malaria control programs and against ectoparasites. The objective of this study was to compare the levels of organochlorine pesticides: HCB, α-β-γ-HCH, pp′-DDE, op′-DDT and pp′-DDT in adipose tissue of female inhabitants from three Mexican states: Veracruz, Puebla and Tabasco. Data analyses indicated higher β-HCH levels in Puebla inhabitants. When comparing the mean values of the pp′-DDE concentrations among the three states, no statistically significant differences were noted. A trend of increasing concentrations of op′-DDT from Veracruz to Puebla and Tabasco was observed. Significantly higher pp′-DDT concentrations in Veracruz as compared to Puebla and Tabasco were determined. Using factorial analysis of three age categories (>30, 31–50, <51) organochlorine pesticide concentrations increases with age of participants, indicating time of exposure as a principal factor of organochlorine pesticides accumulation in adipose tissue.

Fatty acids profile of oil from nine varieties of Macadamia nut

ABSTRACT The fatty acids profile and lipids content of the Macadamia integrifolia and Macadamia tetraphylla varieties and interspecies hybrids, M. integrifolia and M. tetraphylla were analyzed. Total lipids content ranged from 70.9 to 79.7 g of oil per 100 g−1 dry-solids. Gas chromatography/mass spectrophotometry identified 20 fatty acids, the most abundant of which were oleic acid (40 to 51%), palmitoleic acid (24 to 36%), and palmitic acid (8.4 to 13.1%). Fatty acids concentration differed between varieties and hybrids (Multivariate analysis of variance, F = 13.89, p < 0.0001). A ratio of monounsaturated fatty acids:saturated fatty acid values ranged from 2.8 to 4.6. The Huatusco variety (M. integrifolia and M. tetraphylla) exhibited the highest percentage of lipids (79.7 g of oil per 100 g−1 DS) and the highest monounsaturated fatty acids:saturated fatty acid (4.6), thus highlighted its potential applications within the food industry. The Cate variety (M. integrifolia and M. tetraphylla) had the lowest monounsaturated fatty acids:saturated fatty acid, suggesting potential uses in the cosmetics industry.

Enriched environment restricted to gestation accelerates the development of sensory and motor circuits in the rat pup.

The effects of stimulating environments on the neural plasticity of the adult brain have been well explored; however, how an enriched environment (EE) affects the mother‐fetus interaction is poorly understood. We hypothesized that an enriched environment restricted to pregnancy will succeed in accelerating the development of sensory and motor circuits in the offspring. Pregnant Wistar rats were maintained either under a standard condition – two animals per standard cage‐ or an enriched environment – eight subjects in larger cages with different physical configurations‐. After birth, litters from both groups (n = 16 per group) were cross‐fostered with mothers that were simultaneously maintained under standard environment during pregnancy. Sensory and motor development were studied in the pups of both groups with a battery of reflex and physical tests. Auditory and gait reflexes appeared two days earlier in the offspring of EE rats as compared to control subjects (p < 0.05). In addition, EE pups displayed a better performance in righting reflex, inclined board and geotaxis tests (p < 0.05). Differences were found even three weeks after birth. We conclude that EE limited to the phase of pregnancy stimulates the development of pups in utero so that they are born with a higher grade of development.

Foraging Behavior of Apis Mellifera (Hymenoptera: Apidae) and Lycastrirhyncha Nitens (Diptera: Syrphidae) on Pontederia sagittata (Commelinales: Pontederiaceae) on a Disturbed Site

Abstract By influencing the exchange of pollen, floral visitor behavior largely promotes the reproductive success of the plants. Pontederia sagittata (C. Presl) (Commelinales: Pontederiaceae) is a tristylous species whose morphs (long-styled L, mid-styled M and short-styled S) differ in the arrangement of reproductive organs and the amounts and accessibility for food for pollinating insects. We evaluated the behavior of 2 common contemporary visitors to inflorescences, the exotic bee Apis mellifera (L.) (Apidae), a not historical pollinator, and the flower fly Lycastrirhyncha nitens (Bigot) (Syrphidae), a frequent visitor already reported on this aquatic plant, based on HD video records of the number of individuals and the frequency and duration of their visits to 300 inflorescences. Both species of insects preferred to visit S-morph inflorescences. Pollen collection and nectar feeding were the most important activities of the bees, whereas flower flies were observed fed only on nectar. Thus, these behaviors could play an important role in reproduction in the study population of P. sagittata.

Behavioral Repertoires and Interactions between Apis mellifera (Hymenoptera: Apidae) and the Native Bee Lithurgus littoralis (Hymenoptera: Megachilidae) in Flowers of Opuntia huajuapensis (Cactaceae) in the Tehuacán Desert

Abstract The introduction of the honey bee, Apis mellifera L. (Hymenoptera: Apidae), into the arid environments of Mexico has affected the behavioral ecology of native bees. We described the behavioral repertoire and interactions between A. mellifera and the native bee Lithurgus littoralis Cockerell (Hymenoptera: Megachilidae) on Opuntia huajuapensis Bravo (Cactaceae) flowers in a semiarid environment. We filmed the bees in 150 cactus flowers to obtain the diversity of behaviors and their durations and thereby quantify the interactions. The behavior accumulation curve (Clench model) showed differences in the behavioral repertoire between the 2 bee species and between the sexes of L. littoralis. We found that A. mellifera and L. littoralis females invested more time in feeding behavior than L. littoralis males and recorded a wider repertoire of agonistic behaviors in male compared with female bees. Native male bees often perched in flowers and were inactive for long periods. The results indicate a possible interference competition between native and non-native bee species that are visiting the flowers of O. huajuapensis.

Association of Juniperus deppeana (Cupressaceae: Pinales) seeds with Mexican cottontail rabbit (Sylvilagus cunicularius; Leporidae: Lagomorpha) latrines

ABSTRACT Seed aggregation in latrines of rabbits is a little-studied process that may contribute substantially to seed dispersal and survival. We located Juniperus deppeana trees and the latrines used by the endemic Mexican cottontail rabbit Sylvilagus cunicularius within a 1 ha fragment of J. deppeana-dominated forest and evaluated their patterns of aggregation as microhabitats used by cottontail rabbits to consume the J. deppeana galbulus (fleshy cones) or to deposit their pellets with defecated seeds. Based on mean latrine area, we marked a 2 m × 2 m plot centred on the base of every tree or latrine within the study site. We counted all pellets within each plot and analysed them for the presence of seeds of Juniperus or any other species. We found seeds in 13% of all pellets, mainly those deposited in the latrines. If seeds are scarified by passing through the intestinal tract, seed germination in latrines may increase the probability of survival and establishment. Thus, the community structure and density could change in time as rabbits are changing the places where they place their latrines. http://zoobank.org/urn:lsid:zoobank.org:pub:372FEED4-5DFF-4144-A384-4FB30F480A26

Betalaínas, polifenoles y actividad antioxidante en tuna roja mínimamente procesada, almacenada en atmósferas controladas

La tuna roja de Opuntia ficus-indica (L.) Mill. (Cactaceae) es una fuente importante de compuestos biactivos y funcionales, pero tiene dificultades para su almacenamiento y comercializacion. Por lo tanto se realizo un estudio del efecto de las atmosferas controladas sobre los frutos minimamente procesados para conservar los compuestos antioxidantes a temperatura de 5 °C y durante 16 dias de almacenamiento en atmosferas controladas. Al final del mismo se registro que los tratamientos con 5% O2 + 95% N2 y 10% CO2 + 5% O2 + 85% N2 mantuvieron el nivel de betalainas (125,6 mg l-1, 126,16 mg l-1) y actividad antioxidante (263,7 μmol Eq Trolox 100 ml-1, 267,6 μmol Eq Trolox 100 ml-1), respecto al contenido inicial evaluado (116,1 mg l-1, 270,4 μmol Eq Trolox 100 ml-1). Mientras que el contenido de polifenoles no vario en el tratamiento con 5% O2 + 95% N2 (d0-16 ≈ 65,6 - 57,7 mg EAG 100 ml-1). Los resultados indican que aun despues de 16 dias de almacenamiento con el uso de atmosferas controladas, la tuna roja minimamente procesada tiene alta actividad antioxidante puesto que conserva el contenido de betalainas y polifenoles.