Non-specific association between filamentous bacteria and fungus-growing ants

Fungus-growing ants and their fungal cultivar form a highly evolved mutualism that is negatively affected by the specialized parasitic fungus Escovopsis. Filamentous Pseudonocardia bacteria occurring on the cuticle of attine ants have been proposed to form a mutualistic interaction with these ants in which they are vertically transmitted (i.e. from parent to offspring colonies). Given a strictly vertical transmission of Pseudonocardia, the evolutionary theory predicts a reduced genetic variability of symbionts among ant lineages. The aim of this study was to verify whether actinomycetes, which occur on Acromyrmex octospinosus leaf-cutting ants, meet this expectation by comparing their genotypic variability with restriction fragment length polymorphisms. Multiple actinomycete strains could be isolated from both individual ant workers and colonies (one to seven strains per colony). The colony specificity of actinomycete communities was high: Only 15% of all strains were isolated from more than one colony, and just 5% were present in both populations investigated. Partial sequencing of 16S ribosomal deoxyribonucleic acid of two of the isolated strains assigned both of them to the genus Streptomyces. Actinomycetes could also be isolated from workers of the two non-attine ant species Myrmica rugulosa and Lasius flavus. Sixty-two percent of the strains derived from attine ants and 80% of the strains isolated from non-attine ants inhibited the growth of Escovopsis. Our data suggest that the association between attine ants and their actinomycete symbionts is less specific then previously thought. Soil-dwelling actinomycetes may have been dynamically recruited from the environment (horizontal transmission), probably reflecting an adaptation to a diverse community of microbial pathogens.     

Consumer reflections on the usage of plastic bags to parcel hot edible items: an empirical study in Malaysia

The packaging industry offers a wide range of pouching products to their clients in the food and beverage industries, healthcare industries and households as well. It is observed that pouching products are widely used and seemingly making them indispensable. Such practices are commonly found in Malaysia especially to parcel hot or cold food. The use of pouches raises two concerns namely solid waste disposal and food safety. The present study found more than 62% of the consumers purchase hot edible items in plastic bags daily or weekly because of its cost effectiveness and storage convenience. Consumers apparently are unperturbed by public campaigns against the use of plastic bags and neither do government regulations have any influence to reduce the use of plastic bags to parcel hot edible items. On the other hand, consumers are optimistic that the environmental and health hazards from the use of plastic bags to store hot edible items would only see a positive impact in the future.     

Wild fruits as a contribution to sustainable rural development: a case study from the Garhwal Himalaya

Garhwal Himalaya is an important source of wild fruit species. These wild fruit trees grow abundantly across an altitudinal gradient of Himalaya and the majority of them bear fruits during summer. Fruit varieties are eaten raw by the local inhabitants of the region and whilst they are a rich source of protein, carbohydrate, fat and other elements, compared to cultivated fruits, they have not yet been considered as a source of alternative food products. About 13 potentially exploitable species of wild fruits and one semi-domesticated species having high potential for exploitation were selected for study; six (Aegle marmelos, Berberis asiatica, Hippophae rhamnoides, Myrica nagi, Rubus ellipticus and Prunus armeniaca) were examined in detail for their economic potential. Among the wild fruits, Hippophae rhamnoides was found to be economically efficient, followed by Aegle marmelos, Rubus ellipticus and Myrica nagi, respectively. Prunus armeniaca, a semi-domesticated and less utilized fruit of the higher Himalaya, provides better economic returns on an annual basis. The authors have recently made an attempt to utilize these wild fruits as a source of income, particularly for poor rural inhabitants and unemployed youths of the region by making a variety of edible products such as jam, jelly, juice, squash, sauce, etc. The enterprise was demonstrated to the people to encourage them to adopt it in the form of a small village-level cottage industry. The present paper discusses the distribution, botany, phenology, yield, ethnobotany, and uses of these species, and the cost-benefit analysis of food products prepared from them.     

Traditional Ecological Knowledge and Practice for Edible Wild Plants: Biodiversity Use by the Rarámuri,in the Sirerra Tarahumara,Mexico

The Rarámuri who live in the Sierra Tarahumara of Chihuahua State, Mexico have developed local knowledge and harvesting strategies for edible wild plants that have the effect of conserving the biodiversity of their forest ecosystem. This paper presents the results of ethnobotanical research undertaken in the community of Basìhuare in the Sierra Tarahumara, to provide details on some practical aspects of the Raráamuri worldview regarding interconnections between people and their environment. This traditional philosophy forms the basis for the use of edible wild plants and the harvesting strategies practiced in Basìhuare, such as selective harvesting, environmental modification and domestication. These activities provide the opportunity for harvesters to monitor the landscape and the plant resources that occur on the land, as well as present a setting for the communication and exchange of traditional ecological knowledge. However, Rarámuri harvesting practices are under stress because of increased external pressures from commercial timber extraction and other development. We discuss the state of traditional ecological knowledge and its transmission in the context of development activities in the region. The key to sustainability in the Sierra Tarahumara may be the maintenance of traditional management practices for edible wild plants, and other nontimber forest products, that lead to the conservation of biodiversity by creating patchiness and renewing the plant cover on the land.     

Total mercury content found in edible tissues of top predator fish from the Gulf of California,Mexico

Fish at the top of the food chain bioaccumulate and biomagnify toxic metals including mercury (Hg), at a higher rate than nonpredatory fish. However, although some top predator fish species are important in the human diet, the risks for consumers in Mexico are difficult to evaluate due to the scarce baseline information available. In the present article, data on the total mercury (THg) concentrations found in edible tissues of different species of sharks, rays, large pelagic fishes and groupers from the Gulf of California are presented and compared with national and international health guidelines. During 2003 and 2004, 73 shark dorsal tissue samples, 52 ray samples, 66 large pelagic fish samples and 16 grouper samples were collected at different sites along the Gulf of California. Samples were digested in a microwave system and analyzed by cold vapor atomic absorption spectrophotometry. Thirty samples (14%) showed concentrations of Hg above the national statutory limit of 1?mg?kg^?1, from which 25 samples were sharks and 3 were large pelagic fishes. A positive correlation was found between the natural log of THg [ln(THg)] and total length (TL cm) in species of sharks, rays and groupers. The Teacapán estuary in Sinaloa was detected as a possible source of Hg into the Gulf of California due to historic mining in the watershed. Mean Hg concentrations exceeded the regulatory limit of 1?mg?kg^?1 in the following highly commercial shark species: smooth hammerhead, pelagic thrasher, pacific sharpnose shark, dusky shark, scalloped hammerhead, and whitenose shark, in that order. It is recommended that preventive food advisories be issued with respect to these species until further investigations are conducted.     

活性白土对餐饮业废油脂脱色工艺的探索

选用活性白土对餐饮业废油脂进行脱色研究,对脱色率的影响因素进行了讨论。摸索出活性白土的最佳脱色条件：活性白土用量5％;初始脱色温度60C;终止脱色温度120C;脱色时间25min。     

The distribution of macronutrients,anti-nutrients and essential elements in nettles,Laportea peduncularis susp. peduncularis (River nettle) and Urtica dioica (Stinging nettle)

Laportea peduncularis and Urtica dioica, which are popularly known as “Nettles” belong to the plant family Urticaceae and are consumed as green vegetables or used for their medicinal benefit in many countries in Africa, Asia, Europe and America. This study aimed at investigating the effect of cooking on the macronutrient, anti-nutrient and elemental composition of L. peduncularis and U. dioica leaves. The results showed a decrease in the crude fat, ash, carbohydrate and vitamin C content with cooking, but an increase in the vitamin E content. The anti-nutrient content (cyanides, phytates and saponins) increased slightly with cooking, while the oxalate content has decreased. The concentration of essential elements in cooked L. peduncularis leaves were found to be in decreasing order of Ca > Mg > Fe > Mn > Zn > Cu > Cr > Ni > Co. Both raw and cooked leaves of nettles were found to be rich sources of macronutrients and essential elements and may be used as alternatives to commercially available nutrient supplements. Statistical analyses (principal component analysis and correlations) indicated that certain elements taken up by these plants were from common sources. Both positive and negative relationships between nutrients, anti-nutrients and elements were observed in the plant leaves.     

Evaluation of heavy metal concentrations of edible wild-grown mushrooms from China

ABSTRACT

The heavy metal contents (Co, Cu, Fe, Mn, Ni, and Zn) of eight species of wild edible mushrooms from China were determined. The analyses were performed using inductively coupled plasma atomic emission spectrophotometry after microwave digestion. The contents of Co, Cu, Fe, Mn, Ni, and Zn in caps of mushroom samples were 0.7–7.2, 16.2–70.4, 371–1315, 12.5–29.8, 7.1–58.5, and 77.8–187.4 mg kg^?1 dry matter (dm), respectively, while considerable differences were found to be 1.8–25.9, 9.8–36.3, 288–6762, 13.3–103.9, 5.9–78.7, and 38.7–118 mg kg^?1 dm for stipes. The results indicated that higher levels of Co, Fe, and Ni were found in the mushrooms samples analyzed. Zinc and manganese levels were similar to previous reports, whereas Cu was lower than literature values. Correlation analysis suggested that significant correlations were found between the minerals determined and the greatest amount of contamination is associated with Co, Mn, Ni, and Fe. The results of this study indicate that heavy metal contents in mushroom species are mainly related to the mineral resources of sampling sites.     

Sneak in or repel your enemy: Dufour's gland repellent as a strategy for successful usurpation in the slave-maker Polyergus rufescens

Summary. The dulotic queen ant, Polyergus rufescens, must first penetrate a host colony and kill the resident queen in order to successfully founding a new colony. Successful usurpation by a newly mated queen predictably depends on a dual strategy. Although, it can sneak in by being “chemically insignificant” with respect to cuticular hydrocarbons, it may also need to deter prospective host-worker aggressors. Chemical analysis of Dufour's gland secretion of P. rufescens queens and workers by GS/MS revealed that queen secretion is typified by esters of butanoic acid and acetic acid, of which decyl butanoate comprises over 80%. Butanoates and acetates are also present in the workers' secretion, but these are of higher molecular weight, and octadecyl butanoate represents the major compound. Using synthetic mixtures of queen and worker Dufour's gland, we tested the hypothesis that these secretions modify the aggressive behavior of the host species Formica cunicularia>. The queen-like synthetic mixture significantly reduced aggression of the host workers towards alien conspecifics, but neither pentane nor the worker-like synthetic mixture showed this effect. Although Dufour's gland content of >Polyergus queens was suggested to function as an appeasement pheromone (Topoff et al. 1988; Mori et al. 2000), we hypothesized that it may in fact act as a repellent. In order to test this hypothesis we exposed starved F. cunicularia workers to a droplet of honey on a glass slide applied with one of the following compounds: decyl butanoate (queen major compound), octadecyl butanoate (worker main compound), limonene (a reported ant repellent), and pentane (solvent control). Of these, the workers were repelled only by the decyl butanoate and did not approach the honey. We conclude that during usurpation the queen actively repels aggressive workers by emitting Dufour's gland repellent, comprising the alternative tactic in the usurpation dual strategy. This represents another chemical weapon in the diverse arsenal used by parasites to overcome the host's resistance. Received 7 April 2000; accepted 17 May 2000     

Heavy metal concentrations in edible bivalves and gastropods available in major markets of the Pearl River Delta

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