Lima

Storage proteins were extracted from sugarcane seeds, globular embryos (formed on embryogenic calluses and collected in early developmental stages) and embryogenic cells. In all cases, the major percentage of storage proteins were albumins and globulins and the lower percentage were prolamins and glutelins. Sugarcane is an interesting exception in monocots which usually have high levels of prolamins and glutelins.

With the aim to determine a possible relationship between somatic embryogenesis and some metabolic contents in embryogenic and non-embryogenic calluses of sugarcane (Saccharum sp. var CP-5243), the present study was carried out. Embryogenic callus has more soluble proteins, free proline, proteolytic activity, soluble sugars, and invertase, and lower putreseine/(spermidine + spermine) than non-embryogenic tissue. Non-embryogenic callus has a higher peroxidase and gallic acid level, lower dry matter/fresh matter ratio, and more gross fat compared with embryogenic callus.

Plant regeneration from cultured immature inflorescence segments (3–5 mm) of sugarcane (Saccharum sp) var. CP 5243 was obtained via somatic embryogenesis. Embryogenic callus culture was initiated on MS medium supplemented with 2,4-D (13.5 µM) over 30 days. The callus was subcultured every 15–20 days on MS medium supplemented with 2,4-D (4.5 µM), arginine (50 mg l-1) and proline (500 mg l-1). The callus was subjected to five treatments: 2,4-D (4.5 µM), Picloram (8.2 µM) and Dicamba (22.6 µM). SPC was determined at the beginning, after 20 days in culture, and every 24 hours thereafter up to 72 hours. SDS-PAGE electrophoresis was performed based on soluble protein content. Some differences were found between SPC and bands (intensity and number) for all treatments associated with shoot formation. The results point out the association of soluble protein content and callus regenerative ability of sugarcane cv. CP5243 and suggest the presence of a marker protein (between 55–70 kDa) for embryogenic callus regeneration ability in this cultivar.

Embryogenic calli of sugarcane (Saccharum sp. hybrid, clone CP52-43), with somatic embryos in the late scutelar stage, were subjected to different treatments for increasing embryo tolerance to desiccation. The medium was supplemented with abscisic acid (ABA) (3.8 μM), jasmonic acid (JA) (4.7 μM) or a combination of them. A control treatment without growth regulators was also included. The embryos were encapsulated in alginate beads and dehydrated or not in sucrose (0.5 M). Thereafter, they were further dehydrated in chambers containing silicagel until the beads reached either 60% or 30% of water content (WC). Survival of encapsulated-dehydrated embryos was achieved only in the control and ABA treatment. ABA induced an increase in protein, polyamines, free proline levels and starch levels as a response to desiccation tolerance. JA treatment showed the lowest protein and polyamines levels and increased the starch content almost two-fold compared to the ABA treatment. The JA treatment induced high levels of 4-methylcatechol and the lowest levels of gallic acid. However, the ABA treatment increased gallic acid and p-coumaric acid content in the induction medium. Some differences were found in growth regulator free-medium in relation to the induction medium. JA is not effective in these desiccation processes. The mechanisms by which these two plant growth regulators act on the induction of tolerance to stress are presumably different.

The aim of this study was to evaluate the effect of arginine on sugarcane (Saccharum sp.) somatic embryogenesis, free polyamines and other nitrogenous compounds contents. Segments of leaves were used as explants to establish embryogenic cultures on media with 0 and 50.0 mg l−1 arginine. Somatic embryos formation and free polyamines, free proline and total soluble proteins contents were compared. Arginine significantly induced sugarcane somatic embryogenesis. Free proline and protein levels determined in embryogenic cell masses during embryo differentiation-maturation, showed an arginine-induced promotion associated to the enhancement of the embryogenic process. In addition, free putrescine and, in a minor extent, spermidine and spermine contents were enhanced by arginine.

This study shows the behaviour of sugarcane plants cv. CP-5243 derived from artificial seed compared with traditional and isolated bud methods. Artificial seed-acclimatised plants were planted in field conditions simultaneously with two-control treatments previously germinated: macropropagated plants derived from stems of three buds and axillary buds isolated from field-grown plants. Plants from artificial seed were taller and had a smaller diameter at 8 months, but these differences disappeared at 12 months. With respect to sugar analysis and yield, no differences in all parameters evaluated were found between artificial seed-derived plants and plants derived from the two other methods.

Whereas fisheries acoustics data processing mainly focused on the detection, characterization, and recognition of individual fish schools, here we addressed the characterization and discrimination of fish school clusters. The proposed scheme relied on the application of the Bags-of-Features (BoF) approach to acoustic echograms. This approach is widely exploited for pattern recognition issues and naturally applies here, considering fish schools as the relevant elementary objects. It relies on the extraction and categorization of fish schools in fisheries acoustic data. Echogram descriptors were computed per unit echogram length as the numbers of schools in different school categories. We applied this approach to the discrimination of juvenile and adult anchovy ( Engraulis ringens ) off Peru. Whereas the discrimination of individual schools is low (below 70%), the proposed BoF scheme achieved between 89% and 92% of correct classification of juvenile and adult echograms for different s...

Small pelagic fish aggregate within areas of suitable habitat to form patchy distributions with localized peaks in abundance. This presents challenges for geostatistical methods designed to investigate the processes underpinning the spatial distribution of stocks and simulate distributions for further analysis. In two-stage models, presence–absence is treated as separable and independent from the process explaining nonzero densities. This is appropriate where gaps in the distribution are attributable to one process and conditional abundance to another, but less so where patchiness is attributable primarily to the strong schooling tendencies of small pelagic fish within suitable habitat. We therefore developed a new modelling framework based on a truncated Gaussian random field (GRF) within a Bayesian framework. We evaluated this method using simulated test data and then applied it to acoustic survey data for Peruvian anchoveta (Engraulis ringens). We assessed the method’s performanc...

Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. We analyse contemporaneous data on the diving locations of two seabird species, the shallow-diving Peruvian Booby (Sula variegata) and deeper-diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique dataset, we develop resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper ...

A Spatial Eulerian Ecosystem and Population Dynamic Model (SEAPODYM) is used in a data assimilation study aiming to estimate model parameters that describe spawning conditions and dynamics of anchoveta and sardine larvae in the Humboldt Current system (HCS) off Peru. Initially developed for large pelagic fish (e.g., tuna), SEAPODYM was adapted for this study to small pelagic species, and configured to a regional domain using the ROMS-PISCES coupled physicalbiogeochemical model as an input. Environmental variables are used to define a spawning habitat. This habitat is critical since it controls the initial recruitment of larvae in the first cohort and subsequent spatiotemporal variability of natural mortality during their drift with currents described by a system of Eulerian equations. We conducted a series of optimization experiments using data of anchovy and sardine larvae to estimate the parameters of the spawning habitat of both species. Different mechanisms proposed to control t...

During the BIC Humboldt, Olaya y SNP2 0209-11 cruise, the hydroacoustic evaluation method was used. The sampling was done according to the methodology established by the IMARPE. The Peruvian anchoveta (7,433.429 t) was the most abundant species; it showed a coastal distribution, continuous from Paita to San Juan, and dashed towards the south of this locality, reached the greater abundance off Paita to Punta La Negra and off Cerro Azul to Tambo de Mora. The vinciguerria (5,790.910 t), widely distributed in the area evaluated was more frequent off Punta Infiernillos and Ilo, and more abundant from Chala to Ilo. The carrot lobster (2,418.569 t) was the second most abundant species in cold coastal waters (CCW), it was found continuous off Pucusana to Chicama and discontinuous off Pisco to Morro Sama. Jack mackerel (446,782 t) and Pacific mackerel (66,246 t); were scarce; the reduction of these two species has been recorded since September 1998. The longnose anchovy (28,606 t) was found ...

In fluctuating environments, matching breeding timing to periods of high resource availability is crucial for the fitness of many vertebrate species, and may have major consequences on population health. Yet, our understanding of the proximate environmental cues driving seasonal breeding is limited. This is particularly the case in marine ecosystems, where key environmental factors and prey abundance and availability are seldom quantified. The Northern Humboldt Current System (NHCS) is a highly productive, low-latitude ecosystem of moderate seasonality. In this ecosystem, three tropical seabird species (the Guanay Cormorant Phalacrocorax bougainvillii, the Peruvian Booby Sula variegata, and the Peruvian Pelican Pelecanus thagus) live in sympatry and prey almost exclusively on anchovy, Engraulis ringens. From January 2003 to December 2012, we monitored 31 breeding sites along the Peruvian coast to investigate the breeding cycle of these species. We tested for relationships between br...

En el presente estudio se caracterizaron agregaciones de krill (Euphasia superba) identificadas en el Estrecho de Bransfield y los alrededores de la Isla Elefante. Los datos fueron recolectados con una ecosonda multifrecuencia SIMRAD EK80 durante tres veranos australes 2018, 2019 y 2020. Para la detección de agrega-ciones de krill se utilizaron dos frecuencias (38 y 120 kHz) y un algoritmo incluido en un programa destinado para el post procesamiento denominado Echoview versión 9, automatizado con el paquete EchoviewR en R. Se detectaron un total de 22.221 agregaciones. Los descriptores acústicos fueron analizados con la correlación de Pearson. Para la caracterización de agregaciones de krill se aplicó un análisis de componentes principales (PCA), seguidamente de un agrupamiento jerárquico. Para determinar las diferencias temporales de los clústeres fue aplicado un análisis de varianza ANOVA. Además, a las agregaciones de krill se le asignaron las variables ambientales superficiales ...