Effect of Transglutaminase,Citrate Buffer,and Temperature on a Soft Wheat Flour Dough System

Transglutaminase (TGase) can improve the functional characteristics of proteins by introducing covalent bonds inter‐ or intrachains. Temperature and pH interfere with the protein structure and the catalytic activity of enzymes. Because these three factors can act synergistically, TGase, citrate buffer, and temperature were evaluated for their effects on the rheological and chemical changes in low‐protein wheat flour dough. Dough strength, measured by microextension test, significantly increased with increasing levels of TGase (8 U/g of protein), with changes in pH of the citrate buffer (pH 6.5), and by the effect of interaction between these factors. The same trend was observed in the size‐exclusion HPLC measurements, indicating that these two parameters have the effect of increasing gluten protein aggregation. Temperature had a significant effect on dough extension, measured by microextension test. The changes in secondary structure of gluten protein were investigated by FTIR second‐derivative spectra (amide I region, 1,600–1,700 cm⁻¹) and showed an increase in β‐sheet structures initiated by TGase, citrate buffer pH, and their interaction.     

Efficiency of sperm-mediated gene transfer in the ovine by laparoscopic insemination, in vitro fertilization and ICSI

Transgenesis constitutes an important tool for pharmacological protein production and livestock improvement. We evaluated the potential of laparoscopic insemination (LI), in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) to produce egfp-expressing ovine embryos, using spermatozoa previously exposed to pCX-EGFP plasmid in two different sperm/DNA incubation treatments: "Long Incubation" (2 h at 17 C) and "Short Incubation" (5 min at 5 C). For LI, Merino sheep were superovulated and inseminated with treated fresh semen from Merino rams. The embryos were recovered by flushing the uterine horns. For IVF and ICSI, slaughterhouse oocytes were fertilized with DNA-treated frozen/thawed sperm. All recovered embryos were exposed to blue light (488 nm) to determine green fluorescent morulae and blastocysts rates. High cleavage and morulae/blastocysts rates accompanied the LI and IVF procedures, but no egfp-expressing embryos resulted. In contrast, regardless of the sperm/plasmid incubation treatment, egfp-expressing morulae and blastocysts were always obtained by ICSI, and the highest transgenesis rate (91.6%) was achieved with Short Incubation. In addition, following the incubation of labeled plasmid DNA, after Long or Short exposure treatments, with fresh or frozen/thawed spermatozoa, only non-motile fresh spermatozoa could maintain an attached plasmid after washing procedures. No amplification product could be detected following PCR treatment of LI embryos whose zonae pellucidae (ZP) had been removed. In order to establish conditions for transgenic ICSI in the ovine, we compared three different activation treatments, and over 60% of the obtained blastocysts expressed the transgene. For ICSI embryos, FISH analysis found possible signals compatible with integration events. In conclusion, our results show that in the ovine, under the conditions studied, ICSI is the only method capable of producing exogenous gene-expressing embryos using spermatozoa as vectors.     

How much do soil and water contribute to the composition of meat? A case study: meat from three areas of Argentina

The main goal of this study was to propose a reliable method to verify the geographical origin of meat, establishing the influence of soil and water on its isotopic and elemental composition. Thus, beef meat, soil, and water samples were collected from three major cattle-producing regions of Argentina (Buenos Aires, Córdoba, and Entre Ríos). Multielemental composition was determined on these three matrices by inductively coupled plasma mass spectrometry (ICP-MS), δ(13)C and δ(15)N by isotope-ratio mass spectrometry (IRMS), and the (87)Sr/(86)Sr ratio by thermal ionization mass spectrometry (TIMS). Soil and drinking water samples could be characterized and clearly differentiated by combining the isotopic ratios and elements, demonstrating differences in geology and climatic conditions of three regions. Similarly, meat originating at each sampling area was characterized and differentiated using only five key variables (Rb, Ca/Sr, δ(13)C, δ(15)N, and (87)Sr/(86)Sr). Generalized procrustes analysis (GPA), using the three studied matrices (soil, water, and meat) shows consensus between them and clear differences between studied areas. Furthermore, canonical correlation analysis (CCA) demonstrates significant correlation between the chemical-isotopic profile of meat with those corresponding to both soil and water (r(2) = 0.93, p < 0.001; and r(2) = 0.83, p < 0.001, respectively). So far, there are clear coincidences between the meat fingerprint and those from soil/water where cattle grew, presenting a good method to establish beef provenance. To the authors' knowledge this is the first report linking the influence of soil and water all together on the composition of beef, presenting the basis for the authentication of Argentinean beef, which could be extended to meat from different provenances.     

Oribatid mites as intermediate hosts of Thysanosoma actinioides (Cestoda: Anoplocephalidae): a preliminary study.

Thysanosoma actinioides Diesing, 1834 (Cestoda: Anoplocephalidae) parasitizes domestic and wild herbivores, and its life cycle has not yet been completely elucidated. The aim of this study was to analyze the role of oribatid mites as intermediate hosts of T. actinioides. The work was carried out at a Merino sheep breeding farm situated in the Pre-Cordillera region near Bariloche City, Río Negro Province, Argentina. The proglottids of T. actinioides were obtained from feces of infected sheep. In the laboratory, they were placed in the plastic wells with oribatid mites. The species of oribatids used in this experimental trial were Zygoribatula striassima Hammer, 1962 (Family Oribatulidae) and Oribatella spp. Banks, 1895 (Family Oribatellidae). Both species became infected with larval stages of T. actinioides. However, the infective cysticercoid stage did not develop.     

Diet trials on tehuelche scallop Aequipecten tehuelchus (d''Orb) larvae

Laboratory spawned one week old veliger larvaeof the tehuelche scallop, Aequipectentehuelchus (D'Orb., 1846), were reared topedivelger stage under three different dietaryregimes in order to determine the best algalcombination under standard hatchery conditions.Veligers were cultured at mean densities of 2.7larvae/ml. Larval growth and survival wereassessed on larvae fed the following dietarytreatments: (1) Isochrysis galbana(T-Iso)+ Chaetoceros calcitrans, (2)Pavlova lutheri + C calcitrans, and (3)P. lutheri + I. galbana T-Iso +Ch. calcitrans. The highest growth rateswere detected on larvae fed diets includingP. lutheri.     

Reproductive cycle,collection and early growth of Aulacomya ater,Molina 1782 (Bivalvia: Mytilidae) in northern Chile

We evaluated the reproductive cycle of Aulacomya ater at Caleta Punta Arenas (Antofagasta, Chile), finding two important spawning periods (August–September and October–November) associated with declining water temperatures. Mytilid collectors were installed at Caleta Punta Arenas and Caleta Errázuriz (250 km further south) in November and then extracted in consecutive time periods. The results showed settlements of A. ater along with Choromytilus chorus (Molina) and Semimytilus algosus (Gould). An analysis of the spat size structure from each period revealed different micro‐cohorts for each species; the micro‐cohorts of C. chorus were predominant. Daily growth rates were estimated using the average sizes of the micro‐cohorts on two consecutive dates. Although the daily growth rates did not vary significantly between sites for a given species, these rates were lowest for A. ater and highest for S. algosus. The abundance and greater growth of C. chorus caused interspecific competition with A. ater that was detrimental to the survival of the latter. We hypothesize the existence of a metapopulation of A. ater in northern Chile that would explain the settlement of four micro‐cohorts on collectors after 28 days at Caleta Punta Arenas, and the settlement recorded after 80 days at Caleta Errázuriz.     

<Emphasis Type="Italic">Clavibacter michiganensis</Emphasis> subsp. <Emphasis Type="Italic">michiganens</Emphasis>is strains virulence and genetic diversity. a first study in Argentina

Tomato leaves showing severe leaf spot symptoms have been observed and sampled in the central west and southwest Taiwan during 2015 and 2016. The symptoms were similar to those of bacterial leaf spot/late blight diseases, but only Stemphylium-like fungi were consistently isolated from the diseased tomato. Upon spray inoculation of tomato, Stemphylium-like isolates caused leaf spot symptoms identical to those of naturally infected plants, and the pathogenic isolates were successfully re-isolated from inoculated leaves. The tomato-pathogenic isolates were identified as S. lycopersici based on morphological characterization and molecular identification. S. lycopersici has been previously reported to cause gray leaf spot of tomato in the temperate regions, but the majority of S. lycopersici-caused lesions were black/dark brown rather than gray in our surveillance. Accordingly, it is suggested that S. lycopersici-caused disease of tomato is named Stemphylium leaf spot of tomato more appropriately than tomato gray leaf spot. Moreover, S. lycopersici-caused leaf spot disease on tomato has been distributed in major tomato production regions in Taiwan. The information provided by our study will be important for future breeding of tomato cultivars, especially for tomato producers in Taiwan.