Biological Preservation Research Articles

Evaluating experiential education through an intertidal ecology field trip.

Abstract Background/Question/Methods Stanford SEEDS and the Jasper Ridge Biological Preserve have worked together with Redwood High School to implement an experiential ecology education program. The Redwood Environmental Academy of Leadership(REAL) is designed to bring underserved high school students out of the classroom and into the outdoors to create a unique and effective learning experience. Though the program focuses on riparian ecosystem restoration, the course curriculum is interdisciplinary and designed to inspire continuation high school students to attend college or pursue environmental careers. Through a SEEDS special grant, REAL students were taken to Fitzgerald Marine Reserve in Half Moon Bay, California, to learn about marine ecology and intertidal ecosystems at a minus tide. Redwood High School students were joined by their teachers and Stanford faculty and students to study the adaptations of intertidal organisms to their harsh environment. Results/Conclusions SEEDS and REAL were able to evaluate the success of the field trip by comparing the students’ knowledge of intertidal habitat, the nature of the ocean ecosystems, plants, animals, and reproduction both before and after the trip. This opportunity provides insight into the effectiveness of experiential education for the REAL program and recommendations for future ecology outreach programs.

Implant Removal After Submuscular Plating for Pediatric Femur Fractures

Submuscular plating for pediatric femur fracture has become more commonplace for treatment of length unstable fractures. These plates act as an internal fixator and rely on minimally invasive insertion techniques and long plate lengths to achieve the goal of stable fixation and local biologic fracture preservation. Plate removal in children after submuscular plating has not been reported in the literature. We reviewed the records of 22 patients at our institution who were treated with a submuscular plate, which was eventually removed after fracture healing. A review of the radiographs and charts was performed to determine any unique problems or complications that may arise during the removal of these plates given their long lengths and minimally invasive insertion. In our series, 7 patients required a more extensive procedure to remove the plate than was required during plate insertion. These patients all required an open procedure at the leading edge of the plate to chisel overgrown bone away from the plate for removal. The timing of removal in our series was not related to difficulties during plate removal, rather it was the presence of bony overgrowth at the plates leading edge. This overgrowth was seen early on radiographically during the healing process in all patients who required increased operative exposure. The timing of plate removal after submuscular plating is not critical when trying to determine the potential complications at plate removal. The decisive factor related to difficulties with plate removal is leading plate edge overgrowth. Patients with this bone overgrowth at the leading edge of the plate need to be counseled regarding the need for an increased operative exposure during plate removal. Case series, level 4.

Seletividade de diferentes agrotóxicos usados na cultura da soja ao parasitoide de ovos Telenomus remus

A preservação dos agentes de controle biológico no agroecossistema é indispensável para o sucesso do manejo integrado de pragas. Entretanto, o controle químico de pragas ainda é indispensável em diversas culturas. Nesse contexto, a seletividade dos agrotóxicos aos inimigos naturais deve ser sempre considerada na escolha do melhor produto. Portanto, este estudo verificou o impacto causado por diferentes agrotóxicos na emergência do parasitoide de ovos Telenomus remus Nixon (Hymenoptera: Scelionidae), quando aplicados nas fases de larva e pupa (posturas de 100 a 150 ovos de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) seis e 10 dias após o parasitismo, respectivamente). Três ensaios, com 11 tratamentos e cinco repetições, foram conduzidos em laboratório com inseticidas, fungicidas e herbicidas, respectivamente. Cada ensaio foi conduzido com 10 tratamentos de agrotóxicos e água como testemunha seletiva. Todos os produtos fitossanitários foram testados nas doses utilizadas na cultura da soja. Ovos de S. frugiperda parasitados por T. remus foram imersos nos tratamentos por cinco segundos e, após secagem total, foram acondicionados em sacos plásticos até a emergência dos adultos dos parasitoides. A viabilidade do parasitismo foi avaliada, e a redução na emergência dos parasitoides foi classificada segundo as normas da International Organization for Biological Control (IOBC). Os resultados mostraram que os inseticidas do grupo dos reguladores de crescimento, como o flufenoxurom, diflubenzurom e metoxifenozido e também os inseticidas imidacloprido + beta-ciflutrina e acefato, foram seletivos às fases imaturas do parasitoide. Espinosade foi classificado como inócuo para larvas de T. remus. Gama-cialotrina foi levemente nocivo para larvas e inócuo para pupas. Bifentrina e clorpirifós foram, respectivamente, levemente nocivo e nocivo para ambas as fases de desenvolvimento de T. remus. Com relação aos herbicidas testados, 2,4-D, S-metolacloro, flumioxazina, dicloreto de paraquate + diurom, dicloreto de paraquate e glifosato (Roundup Transorb®) foram seletivos. Entretanto, glifosato + imazetapir, clomazona, glifosato (Gliz®), glifosato (Roundup Ready®) foram seletivos para a fase de larva e levemente nocivos (classe 2) para a fase de pupa de T. remus. Resultados semelhantes foram obtidos com os fungicidas flutriafol + tiofanato metílico, carbenzadim, trifloxistrobina + tebuconazole e azoxistrobina + ciproconazole, que foram classificados como inócuos. Tiofanato-metílico, tebuconazole e epoxiconazole + piraclostrobina foram levemente nocivos para larvas e inócuos para pupas. Inversamente, epoxiconazole e azoxistrobina foram seletivos para a fase de larva e levemente nocivos para a fase de pupa do parasitoide. Flutriafol foi classificado como levemente nocivo para ambas as fases de T. remus.

The Past, Present, and Future of Traditional Resource and Environmental Management

We live in a world where biological and cultural diversity are being lost at dizzying rates. As ethnobiologists we know that losses of diversity in both of these realms are inextricably intertwined. The loss of habitats and species, in combination with a plethora of socio-political factors, prevents local and indigenous peoples from interacting with their surrounding environments in traditional ways (e.g., Deur, Turner et al., Weiser and Lepofsky this volume). Traditional practices are important not just because they are often efficient or sustainable ways to harvest and tend economically important resources, but because, for many peoples, these traditional practices are inseparably linked to cultural heritage and cultural survival. Understanding and documenting these practices also can be critical for modern conservation efforts since they often rely on understanding how ecosystems functioned in non-industrial settings, the role of humans in modifying environments, or how human-environmental interactions changed through time and space (e.g., Heckenberger et al. 2003; Pauly 2001; Weiser and Lepofsky this volume). Given that humans had a hand in modifying most landscapes worldwide, understanding the role of humans in ecosystem history is a fundamental first step in managing ecosystems today. This volume arose out of the awareness that 1) there is a welded link between cultural and biological preservation, and 2) there can be considerable benefit in bringing together the ecological knowledge and practice of local and indigenous peoples with current efforts to understand, manage, and conserve today’s ecosystems (e.g., Frazier 2007; Johnson et al. 2005; Lertzman this volume; Lyman and Cannon 2004; Willis et al. 2004). The authors in this volume bring together these topics by examining past, present and future human-environmental interactions that fall under the rubric ‘‘traditional resource and environmental management’’ (TREM; Fowler and Lepofsky in press). Following the lead of others, Kay Fowler and I define TREM as ‘‘the application of traditional ecological knowledge (TEK) to maintain or enhance the productivity, diversity, availability, or other desired qualities of natural resources or ecosystems’’. The term traditional here means the knowledge and practice that are passed down inter-generationally. There is nothing static implied by the term. Rather, it recognizes that such knowledge and practice are built over generations of experimentation and observation about what works given particular cultural and ecological settings (e.g., Berkes and Turner 2006). Sometimes this ecological knowledge emerges from an intimate relationship with one’s surroundings that

The Upper Green River Barcode of Life Project

The DNA barcoding initiative is an international effort to collect standardized DNA sequences from each Eukaryotic species to facilitate taxonomy and specimen identification. DNA barcoding experiments, because they are not technically difficult, are well suited to being used as investigative research experiences in a teaching laboratory. We have implemented a DNA barcoding exercise for our first year “Undergraduate Experience” students in which participants catch arthropods from our university field station, the Upper Green River Biological Preserve. The arthropod specimens were brought to the laboratory, mounted, photographed, and identified via keys and field guides based on morphological characters. This identification served as a working hypothesis for the identity of each specimen. A single leg was removed from each specimen, DNA was extracted, and a fragment of the cytochrome oxidase I gene was PCR amplified and sequenced. Then, using bioinformatics tools, the sequence for each specimen was compared to those in the Barcode of Life and Genbank nucleotide databases. A second species diagnosis based on DNA sequence matches was determined, which could be compared to the original morphological identification, serving as a test of that hypothetical species identity. In its first semester of implementation, 28 arthropod barcodes were produced, which will be augmented by the work of future classes.

Double fossilization in eukaryotic microorganisms from Lower Cretaceous amber

BackgroundMicrofossils are not only useful for elucidating biological macro- and microevolution but also the biogeochemical history of our planet. Pyritization is the most important and extensive mode of preservation of animals and especially of plants. Entrapping in amber, a fossilized resin, is considered an alternative mode of biological preservation. For the first time, the internal organization of 114-million-year-old microfossils entrapped in Lower Cretaceous amber is described and analyzed, using adapted scanning electron microscopy in backscattered electron mode in association with energy dispersive X-ray spectroscopy microanalysis. Double fossilization of several protists included in diverse taxonomical groups and some vegetal debris is described and analyzed.ResultsIn protists without an exoskeleton or shell (ciliates, naked amoebae, flagellates), determinate structures, including the nuclei, surface envelopes (cortex or cytoplasmic membrane) and hyaloplasm are the main sites of pyritization. In protists with a biomineralized skeleton (diatoms), silicon was replaced by pyrite. Permineralization was the main mode of pyritization. Framboidal, subhedral and microcrystalline are the predominant pyrite textures detected in the cells. Abundant pyritized vegetal debris have also been found inside the amber nuggets and the surrounding sediments. This vegetal debris usually contained numerous pyrite framboids and very densely packed polycrystalline pyrite formations infilled with different elements of the secondary xylem.ConclusionEmbedding in amber and pyritization are not always alternative modes of biological preservation during geological times, but double fossilization is possible under certain environmental conditions. Pyritization in protists shows a quite different pattern with regard to plants, due to the different composition and cellular architecture in these microorganisms and organisms. Anaerobic sulphate-reducing bacteria could play a crucial role in this microbial fossilization.

Water activity and glass transition temperatures of disaccharide based buffers for desiccation preservation of biologics

Studying the thermophysical properties of disaccharide based ternary solutions are gaining increasing importance because of their role as excepients in preservation protocols for biologics in general and mammalian cells in particular. Preservation strategies involve not only cryopreservation, but novel approaches like room temperature vitrification and lyophilization. In this study we investigate the water activity and glass transition temperature of citrate and tris buffers (widely used in the gamete preservation industry) with trehalose or sucrose after partial desiccation. After obtaining the water activity (aw) through equilibration at different relative humidity environments, we measured the glass transition temperature (Tg) of these partially desiccated solutions using a differential scanning calorimetry (DSC). The experimental data was used in conjunction with the Gordon-Taylor equation to obtain 3-D contours of Tg as a function of water content and relative salt/sugar concentration. Results indicate that the glass transition behavior is a strong function of the excepient combination. Overall, that trehalose solutions yielded larger values for Tg than sucrose counterparts at low moisture contents in combination with the same buffer. We also saw that citrate solutions yielded larger glass transitions than their tris counterparts. Based on these results, a trehalose-citrate mixture can be picked as the preferred composition for storage applications. The 3-D contours which show a wide variation in slope depending on the salt-sugar concentration constitute important information for the desiccation preservation of biologics.

Management Of Subtrochanteric Femoral Fractures By Dynamic Condylar Screw (DCS)

The present prospective study was done to evaluate the results of Dynamic Condylar Screw (DCS) for the management of subtrochanteric femoral fractures. Twenty five (25) patients were taken up for the study. There were eighteen (18) male (72%) and seven (7) female (28%) patients, with an average age of 45.44 years (ranged 20-70 years). In fifteen (15) patients (60%) the mode of injury was road traffic accident and the ten patients (40%), had injury due to fall. Primary bone grafting was done in four cases (16%) and average time taken to union was 17.56 weeks. Results were evaluated using modified Schatzker and Lambert criteria and were excellent in twenty patients (80%), good in three patients (12%) and fair in two patients (8%). Patients with good quality bone, as per femoral score, had good healing of fractures. Two patients had superficial wound infection, which healed by antibiotics and local wound care. Varus/Valgus/ rotational deformity were seen in four patients, limb length discrepancy was seen in three patients. Two patients had restricted hip movement and one patient had restricted knee movements. To conclude, the Dynamic Condylar Screw for fixation of subtrochanteric fractures has proves to be safe and successful, provided the principles of accurate reduction, stable internal fixation and preservation of biology are followed.

Optimizations for the EcoPod field identification tool.

BackgroundWe sketch our species identification tool for palm sized computers that helps knowledgeable observers with census activities. An algorithm turns an identification matrix into a minimal length series of questions that guide the operator towards identification. Historic observation data from the census geographic area helps minimize question volume. We explore how much historic data is required to boost performance, and whether the use of history negatively impacts identification of rare species. We also explore how characteristics of the matrix interact with the algorithm, and how best to predict the probability of observing a previously unseen species.ResultsPoint counts of birds taken at Stanford University's Jasper Ridge Biological Preserve between 2000 and 2005 were used to examine the algorithm. A computer identified species by correctly answering, and counting the algorithm's questions. We also explored how the character density of the key matrix and the theoretical minimum number of questions for each bird in the matrix influenced the algorithm. Our investigation of the required probability smoothing determined whether Laplace smoothing of observation probabilities was sufficient, or whether the more complex Good-Turing technique is required.ConclusionHistoric data improved identification speed, but only impacted the top 25% most frequently observed birds. For rare birds the history based algorithms did not impose a noticeable penalty in the number of questions required for identification. For our dataset neither age of the historic data, nor the number of observation years impacted the algorithm. Density of characters for different taxa in the identification matrix did not impact the algorithms. Intrinsic differences in identifying different birds did affect the algorithm, but the differences affected the baseline method of not using historic data to exactly the same degree. We found that Laplace smoothing performed better for rare species than Simple Good-Turing, and that, contrary to expectation, the technique did not then adversely affect identification performance for frequently observed birds.

Identification of an antifungal metabolite produced by a potential biocontrol Actinomyces strain A01.

Actinomyces strain A01 was isolated from soil of a vegetable field in the suburb of Beijing, China. According to the morphological, cultural, physiological and biochemical characteristics, and 16S rDNA sequence analysis, strain A01 was identified as Streptomyces lydicus. In the antimicrobial spectrum test strain A01 presented a stable and strong inhibitory activity against several plant pathogenic fungi such as Fusarium oxysporum, Botrytis cinerea, Monilinia laxa, etc. However, no antibacterial activity was found. In pot experiments in greenhouse, the development of tomato gray mold was markedly suppressed by treatment with the fermentation broth of the strain A01, and the control efficacy was higher than those of Pyrimethanil and Polyoxin. A main antifungal compound (purity 99.503%) was obtained from the fermentation broth of strain A01 using column chromatography and HPLC. The chemical structural analysis with U V, IR, MS, and NMR confirmed that the compound produced by the strain A01 is natamycin, a polyene antibiotic produced by S. chattanovgensis, S. natalensis, and S. gilvosporeus, widely used as a natural biological preservative for food according to previous reports. The present study revealed a new producing strain of natamycin and its potential application as a biological control agent for fungal plant diseases.

Modern CaCO 3 preservation in equatorial Pacific sediments in the context of late-Pleistocene glacial cycles

The CaCO 3 content of marine sediments in many regions of the ocean has varied systematically with climate throughout the late-Pleistocene glacial cycles. Both biological productivity and carbonate preservation have been proposed to be the master variable regulating this variability. We have evaluated the preserved flux of CaCO 3 in cores from the central equatorial Pacific Ocean (∼ 140°W) using the 230Th-normalization technique. Neither barite fluxes nor 10Be/ 230Th ratios, both geochemical proxies for export production, correlate with CaCO 3 fluxes, indicating that productivity is not the principal factor controlling CaCO 3 accumulation in these sediments. Preserved fluxes of CaCO 3 in central equatorial Pacific sediments correlate in time with the benchmark CaCO 3 record from the Cape Basin (South Atlantic Ocean), supporting the view that changes in ocean chemistry (carbonate ion concentration) have controlled the pattern of CaCO 3 preservation and accumulation at these sites. Modern CaCO 3 preservation in equatorial Pacific sediments has dropped to levels nearly as low as those experienced at any time in the late Pleistocene. Similar changes occurred at the end of each of the late-Pleistocene interglacial periods, from which we infer that ocean carbonate chemistry has already undergone changes that are expected to precede the transition into the next ice age. However, during the late Pleistocene, the time interval between the decrease in CaCO 3 preservation and the end of the interglacial has varied substantially from one interglacial to another (from ∼ 2000 to ∼ 15,000 years), so the late-Holocene decrease in CaCO 3 preservation cannot be used to predict the end of the Holocene interglacial period.

STUDY THE HURDLE EFFECT OF SOME ORGANIC AND CHEMICAL FOOD PRESERVATIVES ON A RESISTANCE OF BACILLUS CEREUS SP.

Abstract Food preservatives are often added to food as preservation method. Mostly one preservative alone cannot preserve a product effectively. So it is required to create a preservation system to overcome limitations derived from each preservative. Using proper selection of different preservatives may lead to significant practical benefits. In this investigation, resistant strain of Bacillus cereus isolated from pizza cheese containing sodium citrate as a preservative was used to study its sensitivity to different chemical and biological preservatives. The MIC and MBC values of preservatives were measured. Results showed that this bacterium is resistant to permitted concentrations of sodium benzoate, sorbic acid, sodium citrate, potassium sorbate and acetic acid. The sensitivity of this strain was not different from Bacillus cereus PTCC1015. It was realized that citric and benzoic acids (0.187% and 0.006% respectively), sorbic and propionic acids (0.0018% and 0.156% respeetively), propionic acid and potassium sorbate (0.019% and 0.019% respectively), sodium benzoate and propionic acid (0.026% and 0.019% respectively), citric acid and potassium sorbate (0.375% and 0.625% respectively), nisin and propionic acid (125 IU/ml and 0.156% respectively) had synergistic effect on Bacillus cereus. Keywords: Bacillus cereus, Resistant, Preservatives, Synergism, Food

Microbial fermented tea – a potential source of natural food preservatives

Antimicrobial activities of microbial fermented tea are much less known than its health beneficial properties. These antimicrobial activities are generated in natural microbial fermentation process with tea leaves as substrates. The antimicrobial components produced during the fermentation process have shown inhibitory effects against several food-borne and pathogenic bacteria. With the trend of increasing use of natural and biological preservatives in food products, natural antimicrobial agents from microbial fermented tea may offer an innovative and interesting measure for such applications. However, a breakthrough in this field can only be realised after several critical aspects are clarified and further studied. Only then, the application of these potential, novel and natural antimicrobial substances from microbial fermented tea can be industrialized. The present review describes some unique microbial fermentation of tea and the antimicrobial activities formed during the fermentation process. Moreover, future needs in research and development of these antimicrobial compounds from microbial fermentation of tea are discussed for potential industrial applications.

The Use of Free Vascularized Fibular Grafts in Skeletal Reconstruction for Bone Tumors in Children

The reconstruction of large skeletal defects in children following resection of a bone tumor presents a unique challenge to the orthopaedic surgeon. Issues in this population that are not present in the adult population include significant remaining growth potential, the desire for biologic preservation of the joint surface, and the need for a long-term viable reconstruction in patients who are anticipated to survive for decades. The use of a free vascularized fibular graft, supplied by the peroneal vessels in intercalary fibular grafts and the anterior tibial vessels in proximal fibular grafts, has been shown to provide biologic reconstruction that successfully addresses these issues in the pediatric population. Specific techniques are applied in the upper and lower extremity to provide long-term excellent functional results. Experience in microvascular surgery and careful postoperative care are required for the success of these procedures.

Biological preservation of plant derived animal feed with antifungal microorganisms: safety and formulation aspects

During storage of moist animal feed, growth of detrimental fungi causing spoilage, or being mycotoxigenic or pathogenic, is a severe problem. Addition of biopreservative yeasts or lactic acid bacteria can significantly reduce this problem. However, their use requires several careful considerations. One is the safety to the animal, humans and the environment, tightly connected to legal aspects and the need for pre-market authorisation when supplementing feed with microorganisms. Although both yeasts and lactic acid bacteria are considered comparatively safe organisms due to low production of toxic metabolites, it is of great importance to understand the mechanisms behind the biopreservative abilities. Another important issue concerns practical aspects, such as the economic production of large amounts of the organisms and the development of a suitable formulation giving the organisms a long shelf life. These aspects are discussed and a recommendation of this review is that both safety and formulation aspects of a specific microbe should be considered at an early stage in the selection of new organisms with biopreservation potential.

Production of wara, a West African soft cheese using lemon juice as a coagulant

As an important protein source for West African consumers, wara cheese made from the leave extract of Calotropis procera has extremely short shelf life of only 2–3 days [Adegoke, G. O., Nse, E. N., & Akanni, A. O. (1992). Effects of heat, processing time, and pH on the microflora, aflatoxin content, and storability of wara, a soft white cheese. Die Nahrung, 36(3), 259–264; Umoh, V. J., & Solomon, O. (2001). Safety assessment and critical control point of milk product and some cereal beverages in Northern Nigeria. In: Proceedings of USDA/USAID/NIGERIA international conference on food safety and security, August 1–3 (pp. 122–127). Ibadan, Nigeria: IITA; Belewu, M. A., Belewu, K. Y., & Nkwunonwo, C.C. (2005). Effect of biological and chemical preservatives on the shelflife of West African soft cheese. African Journal of Biotechnology, 4, 1076–1079; Adetunji, A. O., Alonge, D. O., & Chen, J. (Unpublished). Microbial quality of wara, a southwestern Nigerian soft cheese]. Lemon juice was used in this study as a substitute coagulant during wara manufacture in order to improve the microbial quality of wara. The cheese was manufactured from pasteurized milk inoculated with 10 1 or 10 2 CFU ml −1 of Listeria monocytogenes. Samples of the milk or cheese were taken along the manufacturing steps and during a 5 d storage period at 15 and 28 °C in order to determine the populations of L. monocytogenes, total aerobes, Enterobacteriaceae, and psychrotrophs, as well as mold and yeast. On the 4th day of storage, portions of the un-inoculated control cheese from 28 °C were deep fried in vegetable oil, mimicking the practice of West African local cheese processors. The results showed that L. monocytogenes, at both inoculation levels, did not survive the manufacture of wara. In samples initially inoculated with 10 1 CFU ml −1 of L. monocytogenes, the Enterobacteriaceae counts decreased from the initial 1.78 to 1.00 Log 10 CFU g −1 with the addition of lemon juice, and became undetectable (<1.00 Log 10 CFU g −1) at the curdling point as well as during the 5 d storage period at both temperatures. The total aerobic counts increased from the undetectable level on the 1st day of storage to 7.65 and 3.39 Log 10 CFU g −1, respectively at 28 or 15 °C on the 5th day of storage. The psychrotrophic, as well as the yeast and mold counts increased from the undetectable levels on the 1st day of storage to 7.11 and 5.03 Log 10 CFU g −1, respectively at 28 °C. At 15 °C however, the population of pyschrotrophs remained undetectable throughout the 5 d storage period whereas, the yeast and molds count increased to 3.08 Log 10 CFU g −1 on day 3 before quickly decreasing to the undetectable levels on the 5th day of storage. A similar trend was observed in cheese made from the milk with an initial Listeria inoculation level of 10 2 CFU ml −1. The results of this study showed that lemon juice significantly reduced the populations of the sampled microorganisms, especially the populations of Enterobacteriaceae.

The significance of small herbivores in structuring annual grassland

AbstractQuestion: Herbivores can play a fundamental role in regulating the composition and structure of terrestrial plant communities. Relatively inconspicuous but nevertheless ubiquitous gastropods and small mammals are usually considered to influence grassland communities through distinct modes. 1. Do terrestrial gastropods and small mammals, either alone or in combination, influence plant community composition of an intact annual grassland? 2. Do these herbivores influence the plant size structure of the dominant grass Avena?Location: Jasper Ridge Biological Preserve (37°24’ N, 122° 13’ W, elevation 150 m) in northern California.Methods: Animal exclosures were used to examine the single and combined influences of these herbivores on annual grassland production, community composition, and plant size structure during the growing season of an intact annual grassland.Results: The removal and exclusion of the herbivores increased the prevalence of grasses relative to legumes and non‐legume forbs; increased total production of above‐ground plant biomass; and increased mean plant size and exacerbated size hierarchies in populations of Avena. The effect of both gastropods and small mammals, alone and in combination, was characterized by temporal oscillations in the relative dominance of grasses in plots with vs. without herbivores.Conclusions: Both groups of herbivores are important controllers of California annual grassland that exert similar influences on production and composition. While other factors appear to determine the absolute number of individuals in this plant community, selective consumption of grasses by gastropods and small mammals partially offsets the competitive advantages associated with their early germination.

The significance of small herbivores in structuring annual grassland

Abstract Question: Herbivores can play a fundamental role in regulating the composition and structure of terrestrial plant communities. Relatively inconspicuous but nevertheless ubiquitous gastropods and small mammals are usually considered to influence grassland communities through distinct modes. 1. Do terrestrial gastropods and small mammals, either alone or in combination, influence plant community composition of an intact annual grassland? 2. Do these herbivores influence the plant size structure of the dominant grass Avena? Location: Jasper Ridge Biological Preserve (37°24′ N, 122°13′ W, elevation 150 m) in northern California. Methods: Animal exclosures were used to examine the single and combined influences of these herbivores on annual grassland production, community composition, and plant size structure during the growing season of an intact annual grassland. Results: The removal and exclusion of the herbivores increased the prevalence of grasses relative to legumes and non-legume forbs; increas...

Nitrite anions induce nitrosative deamination of peptides and proteins

In the present study, reactions of sodium nitrite with proteins/peptides were characterized with mass spectrometry. The reaction generates two major products: replacement of the amino group by a hydroxyl group and formation of an alkene derivative by loss of a NH3 group at the N-terminus and the side chain of lysine residues of proteins/peptides. The reaction proceeds rapidly in weak acidic solution and at 37 degrees C in the presence of a millimolar concentration of nitrite, demonstrating that nitrite induces nitrosative deamination in proteins and peptides. The facile nitrite-induced modification of amino groups of protein/peptides changes the chemical nature of proteins and may have various applications in peptide synthesis, analytical chemistry, and protein engineering. It also provides information to enhance our understanding of functions of nitrite ions in biology and food preservation.

Moisture sorption characteristics and thermophysical properties of trehalose–PBS mixtures

The goal of the study was to quantify the thermophysical properties and the moisture sorption characteristics of the trehalose–PBS (phosphate-buffered saline) from the desiccation preservation perspective. A moisture sorption study was undertaken to determine the desorption isotherms of the trehalose–PBS mixtures. The Brunauer, Emmett, and Teller (BET)—equation and the Guggenheim, Anderson, and de Boer equation were used to quantify the desorption data. The glass transition temperature of the mixtures of trehalose–PBS, equilibrated at different relative humidities was studied using a differential scanning calorimeter. Fourier transform infrared spectroscopy was used to study the molecular interaction between the trehalose and PBS mixtures. The results showed that the addition of PBS to the trehalose mixture causes a shift from the type II isotherm to a type III isotherm (characterized by BET equation) which may have detrimental effect on cell desiccation. The results showed that an increase in PBS mass fraction in the trehalose–PBS mixture causes a decrease in the glass transition temperature ( T g) of the mixture and also a decrease in the hydrogen bonding capacity of the trehalose glasses. The addition of PBS to trehalose posed some challenges and should be subject to further optimization to use it in desiccation preservation of biologics.