Thymic involution produced by diesel exhaust particles and their constituents in mice

Epidemiological studies suggest that diesel exhaust particles (DEP) contribute to an increase in allergic diseases. To assess the effects of DEP on the central immune system, mice were exposed to DEP by intraperitoneal (IP) administration. Exposure to DEP resulted in severe thymic involution accompanied by a reduction in the number of thymocytes, especially in cortical CD4⁺CD8⁺ double positive and double negative subsets. Core carbon particles associated with a mixture of chemical compounds in DEP did not appear to be responsible for the DEP-induced thymic involution because carbon graphite does not affect neither the number nor the CD4/CD8 profile of thymocytes. Extraction of DEP by ether, acidic and basic solvents showed that several independent fractions including the neutral ether fraction, which contains polycyclic aromatic hydrocarbons (PAH), induced thymic involution. Among major PAH components of DEP, benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP), and benzo[k]fluoranthene (BkF) were very potent inducers of thymic involution at an ED50 of less than 100?ng per mouse body. Nonetheless, DEP treatment of mice with targeted disruption of genes encoding the aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), or microsomal epoxide hydolase (mEH) indicated that DEP produced thymic involution even in the absence of PAH-induced AHR/ARNT signal transduction or mEH-mediated PAH catabolism. On the other hand, BaP-mediated thymic involution was completely dependent on AHR, partially dependent on ARNT in T cells, and independent of mEH. These results indicate that DEP-induced thymic involution is mediated both by PAH-AHR/ARNT-dependent and -independent mechanisms.     

Specialized feeding mechanism in the pelagic copepod genus Heterorhabdus (Calanoida: Heterorhabdidae), with special reference to the mandibular tooth and labral glands

Scanning and transmission electron microscopy and gut-content analysis revealed the fine structure of the mandibular ventralmost tooth and labral glands of the carnivorous copepods Heterorhabdus spp. on the basis of the specimens collected in the waters near Nansei Islands, Southwestern Japan, in November 1993. The ventralmost tooth is hollow with a subterminal pore and a basal opening. The distal region of the tooth is like a hypodermic needle and is strengthened by opal layers. The tip of the tooth including the subterminal pore usually protrudes from between the labrum and the paragnath, while the basal region of the ventralmost tooth and the whole parts of the other teeth are semi-enclosed in the preoral food chamber formed by the labrum and the paragnath. There is a large glandular cell in the basal region of the mandibular gnathobase, but no direct connection exists between the gnathobasal cells and the tubular lumen of the ventralmost tooth. The posterior surface of the labrum carries a lateral pair of large glandular pores, which are located close to, and appear to fit exactly the basal openings of the ventralmost teeth. Each of these glands has two massive secretory cells, and the secretory materials from these cells appear to be mixed before discharge from the pore. A specialized feeding mechanism is proposed, wherein venom or anaesthetic is injected from the labral-gland pores into the tubular lumen of the mandibular ventralmost tooth, and then relcased into the prey from its subterminal pore immediately after capture using the stout maxillae of prey macrozooplankters such as copepodids and polychaetes.     

Distribution,structure and importance of the cephalic dorsal hump,a new sensory organ in calanoid copepods

The occurrence, external morphology and internal ultrastructure of a cephalic integumental organ in calanoid copepods were studied, using the specimens from the Pacific, Indian and Atlantic Oceans. This organ is located on the dorsoanterior surface of the cephalosome, and a name, cephalic dorsal hump (CDH) is proposed. Externally, it usually has two pores, anterior and apical, a dorsal plate, and a thin cuticle along the sides. CDH is found only in the male of Calanidae, Megacalanidae, Mecynoceridae and Paracalanidae, and showed some variation between species or species groups both in size and shape. Transmission electron microscopy (TEM) on the specimens from Sagami Bay, Central Japan, revealed that the CDH of Paracalanus parvus and Calanus sinicus consists of two dermal glands and a receptor, which is assumed to be chemosensory. A comparison of the distributions of CDH and prehensile fifth legs of male calanoid copepods suggests that it plays an important role in mate recognition.     

Influence of transportation and pumping on the properties of concrete with large amount of copper slag fine aggregate in actual construction of port and harbor structures

Journal of Material Cycles and Waste Management - Copper slag fine aggregate (CUS) is 30% denser than normal aggregate is an effective material for port and harbor structures demanding high-density...     

Comparison of phenylpropanoid volatiles in male rectal pheromone gland after methyl eugenol consumption, and molecular phylogenetic relationship of four global pest fruit fly species: Bactrocera invadens, B. dorsalis, B. correcta and B. zonata

Males of many tephritid fruit fly species of the genus Bactrocera show a very strong affinity to methyl eugenol (ME). An attracted male compulsively ingests ME, which is then biotransformed before its metabolites are accumulated into the rectal gland. The glandular organ is known to serve as a reservoir for sex pheromone in some species. Upon ME-feeding, males of the oriental fruit fly, Bactrocera dorsalis, selectively accumulated two metabolites, 2-allyl-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (E-CF), in the rectal pheromone gland. We compared the profiles of phenylpropanoid metabolites accumulated by three other species of very high economic and quarantine importance—Bactrocera invadens, Bactrocera zonata and Bactrocera correcta, with that of B. dorsalis. Males of each species were fed artificially on ME and the metabolites stored in the rectal glands were examined by means of chromatography and spectroscopy. Similar to B. dorsalis, males of laboratory-raised B. invadens accumulated DMP and E-CF, in almost equal quantities, in the rectal sac. The sum of DMP and E-CF increased gradually with time after ME consumption and reached as high as 150 μg/male 2 days post ME-feeding. Wild males of B. invadens captured in Kenya also possessed both the compounds in varying quantities. In contrast, males of B. zonata accumulated DMP and (Z)-coniferyl alcohol (Z-CF) in an approximate ratio of 1:1; whereas B. correcta is known to convert ME to (Z)-3,4-dimethoxycinnamyl alcohol (Z-DMC) and Z-CF also in an approximately 1:1 ratio. Thus, there are three types of binary combinations of rectal phenylpropanoid volatiles (i.e. DMP + E-CF; DMP + Z-CF; Z-CF + Z-DMC) utilized among the four Bactrocera species. Such differences in phenylpropanoid ingredients may play a critical role in differentiating these species if encountered in the natural habitat. In this context, the two putative sibling species—B. invadens and B. dorsalis, possess the identical subset of rectal volatiles (DMP and E-CF) in a similar proportion. Furthermore, the phylogenetic analyses of the four Bactrocera species by comparing nucleotide sequences in the mitochondrial genes showed that B. invadens clearly belonged to the same clade as B. dorsalis species. Therefore, we consider the two as the same biological species, and certainly not distinct.     

Stable C and N isotope analysis elucidated the importance of zooplankton in a tropical seagrass bed of Santiago Island,Northwestern Philippines

The role of zooplankton in a tropical seagrass ecosystem was investigated in milkfish farms pollution-impacted and -unimpacted seagrass beds in Santiago Island coral reefs, Northwestern Philippines. The aim was to compare between the two sites: (1) abiotic factors and zooplankton community parameters, and (2) the trophic structure using C and N stable isotopes. Low water (98–119?mV) and sediment (–121 to ?138?mV) Oxidation Reduction Potential values indicated a reducing environment in the impacted site. Zooplankton in the impacted site showed the typical community response to eutrophication (low diversity, but high total abundance due to the dominance of the cyclopoid copepod Oithona oculata), generally few elevated δ¹⁵N values, but a significant shift towards depleted ¹³C due to the organic enrichment of fish-farm feeds. Apart from suggesting a highly complex food web with POM and zooplankton as main food sources in the unimpacted site, the Bayesian mixing model simulation generated reduced complexity in feeding interactions between basal sources, zooplankton, and fish including adults of a key fish species, Siganus fuscescens, in the impacted sites. In this study, C and N stable isotope analysis has clarified the importance of zooplankton as fish prey in a seagrass bed food web.     

Sequestration of plant secondary compounds by butterflies and moths

Summary A number of aposematic butterfly and moth species sequester toxic substances from their host plants. Some of these insects can detect the toxic compounds during food assessment. Some pipevine swallowtails use aristolochic acids among the host finding cues during oviposition and larval feeding and accumulate the toxins in the body tissues throughout all life stages. Likewise, a danaine butterfly,Idea leuconoe, which sequesters high concentrations of pyrrolizidine alkaloids in the body, lays eggs in response to the specific alkaloid components contained in the apocynad host. Insect species sharing the same poisonous host plants may differ in the degree of sequestration of toxins. Two closely ralated aposematic geometrid moth species,Arichanna gaschkevitchii andA. melanaria, sequester a series of highly toxic diterpenoids (grayanotoxins) in different degrees, while a cryptic geometrid species,Biston robstus, does not sequester the toxins, illustrating the diversity in adaptation mechanisms even within the same subfamily. By contrast, a number of lepidopteran species store the same compounds though feeding upon taxonomically diverse plant species. A bitter cyanoglycoside, sarmentosin, was characterised from several moth species in the Geometridae, Zygaenidae and Yponomeutidae, and from the apollo butterflies,Parnassius spp. (Papilionidae), although each species feeds on different groups of plants.Interspecific similarities and differences in life history and ecology are discussed in relation to variable characteristics of sequestration of plant compounds among these lepidopteran insects.     

The seasonal effects of manure management and feeding strategies on hydrogen sulphide emissions from stored dairy manure

Journal of Material Cycles and Waste Management - The influence of temperature and storage time on hydrogen sulphide (H2S) emissions from two different dairy manures was investigated over four...     

Degradation of Polyethylene and Nylon-66 by the Laccase-Mediator System

We investigated whether the laccase-mediator system (LMS) with 1-hydroxybenzotriazole (HBT) as a mediator could degrade high-molecular-weight polyethylene and nylon-66 membranes. The LMS markedly reduced the elongation and tensile strength of these membranes. After 3 days of treatment with the LMS, the M _w of polyethylene decreased from 242,000 to 28,300, and that of nylon-66 from 79,300 to 14,700. The LMS also decreased the polydispersity (M _w/M _n) of polyethylene and nylon-66. Furthermore, these reductions in elongation, tensile strength, and molecular weight were accompanied by morphological disintegration of the polyethylene and nylon-66 membranes. These results strongly suggest that the LMS with HBT can effectively degrade polyethylene and nylon-66.     

Anaerobic co-digestion of dairy cow manure and high concentrated food processing waste

Anaerobic co-digestion of dairy manure (DM) and concentrated food processing wastes (FPW) under thermophilic (55 °C) and mesophilic (35 °C) temperatures, and fertilizer value of the effluent were investigated in this study. Two types of influent feedstock were utilized: 100 % DM and a 7:3 mixture (wet weight basis) of DM and FPW. The contents of the FPW, as feedstock were 3:3:3:1 mixture of cheese whey, animal blood, used cooking oil and residue of fried potato. Four continuous digestion experiments were carried out in 10 L digesters. Co-digestion under thermophilic temperature increased methane production per digester volume. However, co-digestion at 35 °C was inhibited. Total Kjeldahl nitrogen (N) recovered after digestion ranged from 73.1 to 91.9 %, while recoveries of ammonium nitrogen (NH₄-N) exceeded 100 %. The high recovery of NH₄-N was attributed to mineralization of influent organic N. The mixture of DM and FPW showed greater recoveries of NH₄-N after digestion compared to DM only, reflecting its greater organic N degradability. The ratios of extractable to total calcium, phosphorus and magnesium were slightly reduced after digestion. These results indicate that co-digestion of DM and FPW under thermophilic temperature enhances methane production and offers additional benefit of organic fertilizer creation.