Test of the negative feedback hypothesis of colony size sensing in social insects.

Social insects can sense colony size-even without visual information in a dark environment. How they achieve this is yet largely unknown. We empirically tested a hypothesis on the proximate mechanism using ant colonies. In Diacamma colonies, the monogynous queen is known to increase the effort devoted to queen pheromone transmission behaviour (patrolling) as the colony grows, as if she perceives colony size. The negative feedback hypothesis assumes that, through repeated physical contact with workers, the queen monitors the physiological state (fertility) of workers and increases her patrolling effort when she encounters more fertile workers. Supporting this hypothesis, we found that the queen increased her patrolling effort in response to a higher ratio of fertile workers under the experimental condition of constant colony size. Furthermore, chemical analyses and bioassays suggested that cuticular hydrocarbons have queen pheromone activity and can mediate the observed queen-worker communication of fertility state. Such a self-organizing mechanism of sensing colony size may also operate in other social insects living in small colonies.

Gut microbiota development of preterm infants hospitalised in intensive care units.

Gut microbiome development affects infant health and postnatal physiology. The gut microbe assemblages of preterm infants have been reported to be different from that of healthy term infants. However, the patterns of ecosystem development and inter-individual differences remain poorly understood. We investigated hospitalised preterm infant gut microbiota development using 16S rRNA gene amplicons and the metabolic profiles of 268 stool samples obtained from 17 intensive care and 42 term infants to elucidate the dynamics and equilibria of the developing microbiota. Infant gut microbiota were predominated by Gram-positive cocci, Enterobacteriaceae or Bifidobacteriaceae, which showed sequential transitions to Bifidobacteriaceae-dominated microbiota. In neonatal intensive care unit preterm infants (NICU preterm infants), Staphylococcaceae abundance was higher immediately after birth than in healthy term infants, and Bifidobacteriaceae colonisation tended to be delayed. No specific NICU-cared infant enterotype-like cluster was observed, suggesting that the constrained environment only affected the pace of transition, but not infant gut microbiota equilibrium. Moreover, infants with Bifidobacteriaceae-dominated microbiota showed higher acetate concentrations and lower pH, which have been associated with host health. Our data provides an in-depth understanding of gut microbiota development in NICU preterm infants and complements earlier studies. Understanding the patterns and inter-individual differences of the preterm infant gut ecosystem is the first step towards controlling the risk of diseases in premature infants by targeting intestinal microbiota.

Eosinophilic meningitis and hydrocephalus in an infant.

Central nervous system invasion by helminths is the most frequent cause of eosinophilic pleocytosis in the CSF. Although CSF eosinophilia is an unusual finding in the continental United States, it is not an uncommon observation in cases of meningitis in Hawaii and the South Pacific. The rat lungworm, Angiostrongylus cantonensis has been implicated as the causal agent responsible for cases of eosinophilic meningitis in these areas. The diagnosis of eosinophilic meningitis secondary to A cantonensis is generally an indirect one, based on the characteristic clinical findings, documented eosinophilic pleocytosis of the CSF, and history of consumption of food likely to contain infected larvae. Hydrocephalus developed in a 9-month-old infant from Samoa with absolute eosinophilia and an eosinophilic pleocytosis of the CSF.

Plasma levels of natriuretic peptides and adrenomedullin in elderly hypertensive patients: relationships to 24 h blood pressure.

OBJECTIVE: The aim of this study was to investigate the relationships between levels of natriuretic peptides and adrenomedullin and 24 h blood pressure levels in elderly hypertensives. DESIGN AND METHODS: We performed both 24 h ambulatory blood pressure monitoring and measurement of plasma levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and adrenomedullin in 118 asymptomatic hypertensive elderly (> 60 years old) patients. We classified the subjects into groups with isolated clinic hypertension (n = 40) and sustained hypertension (n = 78). We also measured the levels of these peptides in 37 elderly normotensive subjects. RESULTS: Plasma ANP and BNP levels were slightly increased in patients with isolated clinic hypertension compared with elderly normotensives. Among the hypertensives, plasma ANP and BNP levels were more closely related to 24 h blood pressure levels than to office blood pressure levels. Sustained hypertensives showed significantly increased plasma levels of ANP and BNP compared with isolated clinic hypertensives, while adrenomedullin levels were similar in the two groups. Elderly hypertensives with left ventricular hypertrophy detected by electrocardiography had significantly higher levels of ANP and BNP, and higher BNP/ANP ratios than those without left ventricular hypertrophy, while there was no significant difference in adrenomedullin levels between the two groups. CONCLUSIONS: Our results suggest that measurements of ANP and BNP may be useful in detecting left ventricular hypertrophy and in differentiating isolated clinic hypertension from sustained hypertension in elderly hypertensive patients.

Purification of hemagglutinin from Haemophilus paragallinarum using monoclonal antibody.

The purification of hemagglutinin from Haemophilus paragallinarum was attempted using affinity chromatography with monoclonal antibody. The antigen eluted from the affinity column using potassium thiocyanate buffer agglutinated chicken erythrocytes. In immunoblotting of the eluted antigen, a single band with monoclonal antibody was found as well as the crude antigen. When the chickens were immunized with the eluted antigen, they produced the hemagglutination inhibition (HI) antibody, and they showed protection against challenged exposure with H. paragallinarum strain 221. These results indicated that the HA antigen of H. paragallinarum was a protective antigen.

[Effects of argon laser irradiation of the iris on the concentration of aqueous prostaglandins and cyclic AMP].

In order to elucidate the influence of acute ocular inflammation on the aqueous humor dynamics and intraocular pressure (IOP), we carried out argon laser photo-coagulations on the rabbit irises and determined the concentrations of aqueous humor prostaglandins (PGs), cyclic AMP and protein. The IOP changed in a biphasic manner, i.e. initial hypertension and later hypotension. The concentrations of aqueous humor PG E2, PG F2 alpha and protein increased markedly after laser irradiation and then decreased gradually, although the concentrations of PG E2 and protein remained significantly higher than the baseline values at 24 hours after the irradiations. The concentrations of aqueous cyclic AMP of the irradiated eyes and control eyes were 67.8 pmol/ml and 29.3 pmol/ml, respectively. We presumed that the increase in concentration of aqueous cyclic AMP and breakdown of the blood-aqueous barrier by PGs caused the reactive hypotension.

[Intracranial invasion of neuroendocrine carcinoma: a case report].

A rare case of neuroendocrine carcinoma arising from the nasal cavity is reported. A 57-year-old female, who had been complaining of anosmia for 8 years, was admitted to the otolaryngological department because an intranasal tumor was found. Then, removal of the tumor and radiotherapy was carried out. After these procedures, the patient suffered from a high fever and CSF rhinorrhea. At this stage, our neurosurgical department was consulted. CT scan revealed a partially calcified low density mass with a slight enhancement effect at the left frontal base. Under the diagnosis of intracranial invasion by intranasal neuroendocrine carcinoma, the patient was operated on. Through bifrontal craniotomy and a combination of extra- and intradural approach, the tumor was excised. After that, the dura and the skull base were reconstructed. On histological examination, the tumor was found to consist of NSE positive cells forming some glandular structures. Electron microscopic study disclosed neurosecretory granules in the cytoplasmic process. These findings are typical of neuroendocrine carcinoma and compatible to those of the intranasal tumor previously removed. Neuroendocrine carcinoma is rare in itself and there have been reported only two cases of its invasion of the skull base. The clinical features, diagnostic procedures, pathological findings, and treatment of this tumor are discussed in this report.

Identification of trail pheromone precursors from Subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae).

Whole-body extracts of the termite,Coptotermes formosanus Shiraki served for examining the presence of trail pheromone precursor(s). Three trail pheromone precursor candidates, identified as dodecatrienyl stearate, dodecatrienyl oleate, and dodecatrienyl linoleate, were isolated using various chromatographic methods in conjunction with bioassay and by capillary GC-MS analyses.

(Z,E,E)-dodecatrien-1-ol: A minor component of trail pheromone of termite,Coptotermes formosanus Shiraki.

In the course of the elucidation of the primary structure of an isolated trail pheromone fromC. formosanus, a minor component that had the same molecular weight as the major trail pheromone, (Z,Z,E)-3,6,8-dodecatrien-1-ol [(Z,Z,E)-DTE-OH], was detected in the mass chromatogram ofm/z 180 of capillary GC-MS. The mass spectrum of the minor component showed a prominent pattern of dodecatrien-1-ol. Chemical analysis demonstrated that the complete structure was (Z,E,E)-DTE-OH. Furthermore, capillary GC-MS-HR-SIM analysis indicated that the component existed only in the workers ofCoptotermes formosanus Shiraki and was not present in workers ofReticulitermes speratus (Kolbe). This minor component may be a species-specific factor ofC. formosanus, although this was not suggested by a two-choice bioassay.

Drowning risks to epileptic children: a study from Hawaii.

The role of epileptiform seizures in causing drowning and near-drowning among children was studied by examining the case reports of all 140 childhood immersion accidents that occurred in an area of Hawaii over five years. Four of the 140 immersion accidents were caused partly by epileptiform seizures, but none were fatal. The combined results of the Hawaiian and Brisbane studies (total population studied over five years 1 600 000) showed that no epileptic children died from accidents in the sea or in swimming pools; and the 2.9% incidence of immersion accidents due to seizures in the Hawaiian study compares well with the incidence found in other series. If an epileptic child is mentally normal, well controlled with anticonvulsants, and supervised in the water then the risk of drowning is very small.

Isolation of 2-fluorocitrate produced by in vivo dealkylation of 29-fluorostigmasterol in an insect.

A novel pro-insecticide, 29-fluorostigmasterol, is proposed to cause mortality due to release of fluoroacetate during side chain dealkylation. The 29-3H-labeled substrate was fed to third instar tobacco hornworms (Manduca sexta) and erythro-2-fluoro-[2-3H] citrate was isolated in 0.012% yield by ion-exchange, silica gel, and reverse-phase chromatography of the tricarboxylic acid, trimethyl ester, and trimethyl ester benzoate, respectively. The less toxic 29-fluoro-[29-3H]sitosterol did not provide sufficient labeled fluorocitrate to allow isolation, while a more toxic 16-3H-labeled 16-fluorofatty acid gave nearly 1% conversion to labeled fluorocitrate. This is the first direct chemical evidence for the fate of the two carbons removed during phytosterol dealkylation in an insect. It is also the first use of labeled fluoroacetate precursors to identify labeled 2-fluorocitrate as an in vivo metabolite of these precursors.

Evidence for presence and nature of female sex pheromone ofBrithys crini fabricius (Lepidoptera: Noctuidae).

The existence of a female sex pheromone of the noctuid mothBrithys crini Fabricius was confirmed in both laboratory bioassay and field tests. Crude extracts and airborne volatiles from females were analyzed by gas chromatography and mass spectrometry and the data compared with authentic compounds. The primary sex pheromonal compound was Z11-16: Ald. Scanning electron microscopy showed that the external surface of the sex pheromone gland was covered with folds that might increase the sex pheromone evaporation area.

Liquid chromatographic determination of sulfamoyldapsone in swine tissues.

A liquid chromatographic (LC) method is described for the quantitative determination of sulfamoyldapsone (2-sulfamoyl-4,4'-diaminodiphenyl sulfone) in swine muscle, liver, kidney, and fat. Sulfamoyldapsone was extracted from tissues with acetonitrile saturated with n-hexane. The extract was washed with n-hexane saturated with acetonitrile, concentrated, and cleaned up by alumina column chromatography. Sulfamoyldapsone was separated on an ODS column by using acetonitrile-methanol-water (6 + 18 + 76) and was detected at 292 nm. Overall average recovery of sulfamoyldapsone added to tissues at levels of 0.1 and 0.5 microgram/g was 93.3% +/- 6.0. Detection limit was 0.02 microgram/g in these tissues.

Chemical recognition of partner plant species by foundress ant queens in Macaranga-Crematogaster myrmecophytism.

The partnership in the Crematogaster-Macaranga ant-plant interaction is highly species-specific. Because a mutualistic relationship on a Macaranga plant starts with colonization by a foundress queen of a partner Crematogaster species, we hypothesized that the foundress queens select their partner plant species by chemical recognition. We tested this hypothesis with four sympatric Macaranga species and their Crematogaster plant-ant species. We demonstrated that foundress Crematogaster queens can recognize their partner Macaranga species by contact with the surface of the seedlings, that they can recognize compounds from the stem surface of seedlings of their partner plant species, and that the gas chromatographic profiles are characteristic of the plant species. These findings support the hypothesis that foundress queens of the Crematogaster plant-ant species select their partner Macaranga species by recognizing nonvolatile chemical characteristics of the stem surfaces of seedlings.

Taste-enhancing effects of glycine on the sweetness of glucose: a gustatory aspect of symbiosis between the ant, Camponotus japonicus, and the larvae of the lycaenid butterfly, Niphanda fusca.

The lycaenid butterfly, Niphanda fusca, has a parasitic relationship with its host ant, Camponotus japonicus: the caterpillars may use chemical mimicry to enter the ant nest where they are fed mouth-to-mouth by the adult ants until pupation. Nevertheless, larvae offer their host ants a nutritious secretion that contains 160 mM glucose and 43 mM glycine. Using glucose and glycine mixture as artificial secretions, we investigated the gustatory effect of glucose and/or glycine on the ants. Glycine induced neither feeding behavior nor gustatory response in the ants if its concentration was <500 mM. In the presence of glycine at the concentration in the secretion, however, the ants improved their preference to glucose, and the sugar receptor cell exhibited electrophysiological enhancement of response to glucose in a glycine-concentration-dependent manner. By adding glycine to glucose in their secretions, therefore, the butterfly larvae can manipulate the gustatory sense of the ants. The alluring taste of 'glycine-flavored glucose' could motivate the host ants to feed the larvae and thereby receive the secretions as a reward. The taste enhancement created by the combination of sugar and amino acid may play a role in the evolution of the parasitic relationships of these insects. The taste-enhancing effect appears to be analogous to taste enhancement by 'umami' substances in humans.

Evidence for trail-pheromone precursor in termiteReticulitermes speratus (Kolbe) (Rhinotermitidae: Isoptera).

Whole body extracts of the termite,Reticulitermes speratus, were subjected to various chemical operations and bioassays to examine the presence of trail-pheromone precursor. Fractions that mainly contained fatty acid esters were obtained from hexane extracts by means of silica gel column chromatography. Trail-following activity of the fractions was activated by alkaline hydrolysis, while the original fractions did not show any conspicuous activity. Bioassay showed that the activity of hydrolyzed product was approximately 20 times as high as the original hexane extract. This suggests that the precursor candidate could be stored in termite bodies as an esterified form. Chemical analyses revealed that the complete structure of the hydrolyzed product was coincident with that of the native pheromone ((Z,Z,E)-3,6,8-dodecatrien-1-ol).

Comparison of the pathogenicity for chickens of Erysipelothrix rhusiopathiae and Erysipelothrix tonsillarum.

Twenty-two strains of Erysipelothrix rhusiopathiae, 14 strains of Erysipelothrix tonsillarum, and four other strains representing two serovars were examined for virulence in 30- to 40-day-old specific pathogen-free chickens. Some of the chickens that were given strains of serovars la, 2, 5, 6, 8, 9, 15 or 21 of E. rhusiopathiae showed signs of disease, lesions, bacteraemia or recovery of the bacterium. In contrast, there were no clinical signs, pathological lesions or bacterial isolations in chickens inoculated with the E. tonsillarum or other strains. The study thus confirmed that strains of some serovars of E. rhusiopathiae are pathogenic for chickens, but that E. tonsillarum strains are not pathogenic and should be omitted from potential causes of erysipelas in chickens.