Phylogenetics of Australasian gall flies (Diptera: Fergusoninidae): Evolutionary patterns of host-shifting and gall morphology.

This study investigated host-specificity and phylogenetic relationships in Australian galling flies, Fergusonina Malloch (Diptera: Fergusoninidae), in order to assess diversity and explore the evolutionary history of host plant affiliation and gall morphology. A DNA barcoding approach using COI data from 203 Fergusonina specimens from 5gall types on 56 host plant species indicated 85 presumptive fly species. These exhibited a high degree of host specificity; of the 40 species with multiple representatives, each fed only on a single host genus, 29 (72.5%) were strictly monophagous, and 11 (27.5%) were reared from multiple closely related hosts. COI variation within species was not correlated with either sample size or geographic distance. However variation was greater within oligophagous species, consistent with expectations of the initial stages of host-associated divergence during speciation. Phylogenetic analysis using both nuclear and mitochondrial genes revealed host genus-restricted clades but also clear evidence of multiple colonizations of both host plant genus and host species. With the exception of unilocular peagalls, evolution of gall type was somewhat constrained, but to a lesser degree than host plant association. Unilocular peagalls arose more often than any other gall type, were primarily located at the tips of the phylogeny, and did not form clades comprising more than a few species. For ecological reasons, species of this gall type are predicted to harbor substantially less genetic variation than others, possibly reducing evolutionary flexibility resulting in reduced diversification in unilocular gallers.

Pressure resistance of cold-shocked Escherichia coli O157:H7 in ground beef, beef gravy and peptone water.

AIMS: (i) To study the effects of cold shock on Escherichia coli O157:H7 cells. (ii) To determine if cold-shocked E. coli O157:H7 cells at stationary and exponential phases are more pressure-resistant than their non-cold-shocked counterparts. (iii) To investigate the baro-protective role of growth media (0·1% peptone water, beef gravy and ground beef). METHODS AND RESULTS: Quantitative estimates of lethality and sublethal injury were made using the differential plating method. There were no significant differences (P > 0·05) in the number of cells killed; cold-shocked or non-cold-shocked. Cells grown in ground beef (stationary and exponential phases) experienced lowest death compared with peptone water and beef gravy. Cold-shock treatment increased the sublethal injury to cells cultured in peptone water (stationary and exponential phases) and ground beef (exponential phase), but decreased the sublethal injury to cells in beef gravy (stationary phase). CONCLUSIONS: Cold shock did not confer greater resistance to stationary or exponential phase cells pressurized in peptone water, beef gravy or ground beef. Ground beef had the greatest baro-protective effect. SIGNIFICANCE AND IMPACT OF THE STUDY: Real food systems should be used in establishing food safety parameters for high-pressure treatments; micro-organisms are less resistant in model food systems, the use of which may underestimate the organisms' resistance.

Nutritional enhancement of leaves by a psyllid through senescence-like processes: insect manipulation or plant defence?

Some herbivores can modify the physiology of plant modules to meet their nutritional requirements. Induction of premature leaf senescence could benefit herbivores since it is associated with the mobilisation of nutrients. We compared the effects of nymphal feeding by Cardiaspina near densitexta on Eucalyptus moluccana with endogenous processes associated with senescence to assess the relative merits of an insect manipulation or plant defence interpretation of responses. Evidence supporting insect manipulation included increased size of fourth and fifth instar nymphs (in the latter the effect was restricted to forewing pad length of females) on leaves supporting high numbers of conspecifics and feeding preventing leaf necrosis. Intra-specific competition negated greater performance at very high densities. High and very high abundances of nymphs were associated with increased concentrations of amino acid N but only very high abundances of nymphs tended to be associated with increased concentrations of six essential amino acids. Contrary to the insect manipulation interpretation, feeding by very high abundances of nymphs was associated with significant reductions in chlorophyll, carotenoids and anthocyanins. Evidence supporting plant defence included the severity of chlorosis increasing with the abundance of nymphs. Leaf reddening did not develop because ambient conditions associated with photoinhibition (high irradiance and low temperature) were not experienced by leaves with chlorotic lesions. Leaf reddening (from anthocyanins) alone is not expected to adversely affect nymphal survival; only leaf necrosis would kill nymphs. For senescence-inducing psyllids, nutritional enhancement does not fit neatly into either an insect manipulation or plant defence interpretation.

Salivary proteins of plant-feeding hemipteroids - implication in phytophagy.

Many hemipteroids are major pests and vectors of microbial pathogens, infecting crops. Saliva of the hemipteroids is critical in enabling them to be voracious feeders on plants, including the economically important ones. A plethora of hemipteroid salivary enzymes is known to inflict stress in plants, either by degrading the plant tissue or by affecting their normal metabolism. Hemipteroids utilize one of the following three strategies of feeding behaviour: salivary sheath feeding, osmotic-pump feeding and cell-rupture feeding. The last strategy also includes several different tactics such as lacerate-and-flush, lacerate-and-sip and macerate-and-flush. Understanding hemipteroid feeding mechanisms is critical, since feeding behaviour directs salivary composition. Saliva of the Heteroptera that are specialized as fruit and seed feeders, includes cell-degrading enzymes, auchenorrhynchan salivary composition also predominantly consists of cell-degrading enzymes such as amylase and protease, whereas that of the Sternorhyncha includes a variety of allelochemical-detoxifying enzymes. Little is known about the salivary composition of the Thysanoptera. Cell-degrading proteins such as amylase, pectinase, cellulase and pectinesterase enable stylet entry into the plant tissue. In contrast, enzymes such as glutathione peroxidase, laccase and trehalase detoxify plant chemicals, enabling the circumvention of plant-defence mechanisms. Salivary enzymes such as M1-zinc metalloprotease and CLIP-domain serine protease as in Acyrthosiphon pisum (Aphididae), and non-enzymatic proteins such as apolipophorin, ficolin-3-like protein and 'lava-lamp' protein as in Diuraphis noxia (Aphididae) have the capacity to alter host-plant-defence mechanisms. A majority of the hemipteroids feed on phloem, hence Ca++-binding proteins such as C002 protein, calreticulin-like isoform 1 and calmodulin (critical for preventing sieve-plate occlusion) are increasingly being recognized in hemipteroid-plant interactions. Determination of a staggering variety of proteins shows the complexity of hemipteroid saliva: effector proteins localized in hemipteran saliva suggest a similarity to the physiology of pathogen-plant interactions.

PTEN and myotubularin phosphoinositide phosphatases: bringing bioinformatics to the lab bench.

Phosphoinositides play an integral role in a diverse array of cellular signaling processes. Although considerable effort has been directed toward characterizing the kinases that produce inositol lipid second messengers, the study of phosphatases that oppose these kinases remains limited. Current research is focused on the identification of novel lipid phosphatases such as PTEN and myotubularin, their physiologic substrates, signaling pathways and links to human diseases. The use of bioinformatics in conjunction with genetic analyses in model organisms will be essential in elucidating the roles of these enzymes in regulating phosphoinositide-mediated cellular signaling.

Scientific knowledge and clinical authority in dentistry: James Sim Wallace and dental caries.

Once the germ theory had become generally accepted within medicine, the importance of experimental science to the improvement of medical practice could no longer be reasonably doubted. However, clinicians still sought to retain control of how knowledge that had originated in the laboratory was interpreted and applied within practical diagnostics and therapeutics. Thus how practitioners incorporated new scientific knowledge into their medical discourse and practice is a matter for careful empirical inquiry. James Sim Wallace, born in Renfrewshire in 1869 and a graduate in medicine from the University of Glasgow, was a leading figure in British dentistry throughout the first half of the twentieth century. Through an examination of his voluminous writings, we explore how the new 'chemico-parasitical' theory of dental caries was accommodated within dentists' understanding of oral hygiene. The paper also looks at the controversies that surrounded the application of the vitamin theory to the problems of rickets and dental caries, focusing on the contentious interaction between Sim Wallace and his colleagues, on the one hand, and the eminent physiologists May and Edward Mellanby, on the other.

Characterization of phosphatidic acid phosphohydrolase in neutrophil subcellular fractions.

This investigation was designed to confirm the presence of PA phosphohydrolase in human neutrophils and to determine the distribution and characteristics of the enzyme in soluble and particulate subcellular fractions of disrupted neutrophils. Enzyme activity was detected in unseparated extracts of sonicated neutrophils. The majority of the recovered activity was recovered in a particulate fraction rich in neutrophil plasma-membrane markers; moderate levels (20%) of the total activity were recovered in the cytosol. While Mg2+ markedly potentiated the cytosolic but not the particulate activity, Ca2+ moderately inhibited both the cytosolic and particulate enzymes. The plasma-membrane-associated activity was absolutely dependent on detergent (0.5% Triton X-100) and displayed an apparent Km of 62 microM for phosphatidic acid. Enzyme activity was markedly inhibited by NaF, not influenced by excess glycerophosphate and slightly attenuated by propranolol, an inhibitor of PA phosphohydrolase in other systems. Preincubation of plasma membranes with N-ethylmaleimide at concentrations up to 25 mM had little effect on enzyme activity. However, activity in cytosolic and microsomal fractions of neutrophils were completely abolished by preincubation with N-ethylmaleimide at concentrations of less than 5 mM. We conclude that neutrophils possess a potent PA phosphohydrolase localized in their plasma membranes. Metabolism of cellular second-messengers by this enzyme may exert a profound effect on the functions of stimulated neutrophils.

Characteristics of electrogenic sodium pumping in rat myometrium.

Sodium-rich myometrium, obtained from the uteri of pregnant rats, rapidly hyperpolarized when 4.6-120 mM potassium was added to the bathing medium at 37 degrees C. Hyperpolarization was due to sodium pumping since the process was markedly temperature dependent, was abolished by ouabain, and required both intracellular sodium and extracellular potassium. The observed membrane potential exceeded the calculated potassium equilibrium potential during hyperpolarization providing evidence that sodium pumping was electrogenic. Hyperpolarization was reduced in the presence of chloride. The rate of sodium pumping may influence potassium permeability since potassium apparently did not short-circuit the pump during hyperpolarization.

Novel autonomic neurotransmitters and intestinal function.

A wide variety of substances, including amines and peptides, have been detected within the complex neuronal pathways of the enteric nervous system using immunohistochemical techniques. In this article we have discussed some of the more recent data on the effects of these substances on intestinal activity. We have also commented on the many difficulties associated with ascribing neurotransmitter status to individual compounds. The technique of immunoblockade of neurogenic functional responses has been used in an attempt to identify some of the putative neurotransmitter substances. The search for selective antagonists continues.

Effects of nitric oxide (NO) and NO donors on the membrane conductance of circular smooth muscle cells of the guinea-pig proximal colon.

1. The membrane conductance changes underlying the membrane hyperpolarizations induced by nitric oxide (NO), S-nitroso-L-cysteine (NC) and sodium nitroprusside (SNP) were investigated in the circular smooth muscle cells of the guinea-pig proximal colon, by use of standard intracellular microelectrode recording techniques. 2. NO (1%), NC (2.5-25 microM) and SNP (1-1000 microM) induced membrane hyperpolarization in a concentration-dependent manner, the hyperpolarizations to NO and NC developing more rapidly than those to SNP. The slower-developing responses to SNP were mimicked by the membrane permeable analogue of guanosine 3':5' cyclic-monophosphate (cyclic GMP), 8-bromo-cyclic GMP (500 microM), and by isoprenaline (10 microM). 3. The hyperpolarizations to NC and SNP were reduced in a low Ca2+ (0.25 mM) saline and upon the addition of haemoglobin (20 microM), but were not effected by NG-nitro-L-arginine (L-NOARG) (100 microM) or omega-conotoxin GVIA (100 nM). the hyperpolarizations to SNP were also significantly reduced by methylene blue (50 microM). 4. Apamin (250 nM) depolarized the membrane potential approximately 10 mV and reduced the initial transient component of the hyperpolarization to NO (1%) and NC (25 microM), but had no effects on the hyperpolarizations to SNP and cyclic GMP. Tetraethylammonium (TEA) (5-15 mM), had little effect on the membrane responses to NO(1%), NC(2.5-25 microM), SNP(100(-1000) microM) or cyclic GMP(500 microM). However, TEA (5-15 mM) reduced the membrane hyperpolarizations to SNP (10 microM) and isoprenaline (10 microM) in a concentration-dependent manner. The hyperpolarization to isoprenaline (10 microM) remaining in the presence of 15 mM TEA was blocked by ouabain (10 microM). 5. The amplitude of electronic potentials (1 s duration) elicited during NO donor hyperpolarizations were little changed or only slightly reduced (5-25%). However, the amplitude of the electrotonic potentials elicited during maintained electrically-induced hyperpolarizations of similar amplitude were significantly increased (30-150%), suggesting that the non-linear membrane properties of the proximal colon partially mask an increase in membrane conductance elicited during the NO donor hyperpolarizations. 6. Membrane hyperpolarization in the presence of an NO donor, 8-bromo-cyclic GMP, isoprenaline, or upon application of a maintained hyperpolarizing electrical current, often evoked oscillations of the membrane potential. These oscillations were prevented by Cs+ (1 mM). 7. These results indicate that NO and NC hyperpolarize the circular muscle of the proximal colon by activating at least two TEA-resistant membrane K+ conductances, one of which is sensitive to apamin blockade. The K+ conductance increases activated by SNP or 8-bromo-cyclic GMP were little effected by apamin, perhaps suggesting a common mechanism. In contrast, the hyperpolarization to isoprenaline appears to involve the activation of TEA-sensitive Ca2(+)-activated K+ ('BK') channels, as well as a Na:K ATPase. Finally, the 'background' membrane conductance of the circular muscle cells of the proximal colon decreased upon membrane hyperpolarization to reveal oscillations of the membrane potential which may well represent 'pacemaker' or 'slow wave' activity.

The outcome of 26 patients with respiratory syncytial virus infection following allogeneic stem cell transplantation.

Respiratory syncytial virus (RSV) is known to cause acute lung injury in the immunocompromised host, especially recipients of bone marrow allografts. Specific prognostic factors for the development of severe life-threatening disease remain to be identified as does the optimum treatment of established disease. Over a 5-year period the incidence and outcome of RSV in BMT recipients was analysed retrospectively. Prognostic factors assessed included type of transplant, engraftment status at the time of infection, the presence of lower respiratory tract disease, viral genotype and treatment received. During the study period, 26 of 336 (6.3%) allogeneic stem-cell recipients were identified as having RSV. Five patients (19.2%) died as a direct result of RSV. One patient died secondary to an intracranial bleed with concomitant RSV. There were four patients with graft failure (two primary and two secondary) attributable to the presence of RSV, two of whom subsequently died of infections related to prolonged myelosuppression. The presence of lower respiratory tract infection and a poor overall outcome was the only statistically significant association. Unrelated donor transplants and AML as the underlying disease appeared to be associated with a poorer outcome. Engraftment status, viral genotype and RSV treatment received did not correlate with outcome. We conclude that future studies are required to identify early sensitive and reproducible prognostic factors of RSV in the immunocompromised host. The roles of intravenous and nebulised ribavirin need to be clarified by prospective controlled trials.

Colonic migrating motor complexes (CMMCs) in the isolated mouse colon.

Spontaneous contractions were recorded from the circular muscle layer at three sites along the isolated mouse colon. The interval between contractions was approximately 4.5 min. The mean duration of the contractions ranged from 26 sec in the distal colon to 45 sec in the proximal colon. Contractions migrating more than half the length of the colon were termed colonic migrating motor complexes (CMMCs). Over 90% of tissues demonstrated migration predominantly in an aboral direction. Hyoscine (10(-6) M) decreased the amplitude of the CMMCs by at least 40% but had no significant effect on the interval or duration of the CMMCs. Nifedipine (10(-6) M) significantly decreased the amplitude of the CMMCs by 95% but did not alter the duration or the interval between the CMMCs. Hexamethonium (5 x 10(-4) M) and tetrodotoxin (TTX; 2 x 10(-6) M) abolished all CMMC activity. TTX increased the resting tone of the preparations. Nitro-L-arginine (10(-4) M) increased the resting tone of the preparations and significantly decreased the interval between the CMMCs by approximately 80% but had no significant effect on the duration of the CMMCs. The results suggest CMMCs migrate predominantly in an aboral direction and are neurogenic in origin. Nitric oxide may be involved in maintaining inhibition of the muscle between CMMCs.

Antagonism of non-cholinergic excitatory junction potentials in the guinea-pig ileum by a substance P analogue antagonist.

In the presence of atropine electrical transmural stimulation (using repetitive volleys, e.g. 3 pulses at 50 Hz applied every 4 s) of full thickness longitudinal strips of guinea-pig ileum produced non-cholinergic excitatory junction potentials (EJPs) and inhibitory junction potentials (IJPs) in the circular muscle layer. After abolition of the IJPs with apamin, the non-cholinergic EJPs clearly showed facilitation. In the presence of apamin and the substance P analogue antagonist, [D-Arg1,D-Pro2,D-Trp7-9,Leu11]-substance P (SPA), the non-cholinergic EJPs were reduced by 60-90%; transmural stimulation now revealed an apamin-resistant IJP followed by a slow depolarization. The atropine-resistant EJPs are probably caused by the release of substance P (or a similar compound) and are likely to underlie the non-cholinergic contractions reported to occur in this tissue.

Evidence that myoelectric complexes in the isolated mouse colon may not be of myogenic origin.

The hypothesis that spontaneous depolarisations (myoelectric complexes, MCs) can occur in the absence of neuronal activity, depending on the level of the membrane potential, was systematically studied. In control Krebs' solution, MCs were recorded approximately every 5 min and were abolished by tetrodotoxin (TTX, 1.6 microM). However, TTX also induced sustained membrane depolarisation (19 mV) in the circular muscle. To test whether MCs were blocked by the depolarisation induced by TTX, graded membrane repolarisations were generated, in the continuing presence of TTX, using sodium nitroprusside (SNP, 10 nM-1 microM). Under these conditions, MC activity was not restored. The addition of SNP (1 microM) to control preparations, in normal Krebs' solution, hyperpolarised the membrane of the circular muscle cells, but did not inhibit ongoing MC activity. It is suggested that the underlying mechanisms involved in MC generation are unlikely to be dependent upon the level of membrane potential in circular smooth muscle.

Long-term use of 1.1% amino acid dialysis solution in hypoalbuminemic continuous ambulatory peritoneal dialysis patients.

INTRODUCTION: Malnutrition is a common problem in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Hypoalbuminemia in CAPD patients is an independent risk factor for death and is associated with malnutrition. Previous short-term studies have examined the use of amino acid based PD solutions in terms of albumin levels and anthropometric changes, but not clinical outcome. We report on the extended use of 1.1% amino acid based peritoneal dialysis solution (Nutrineal) and have assessed clinical utility in terms of nutrition, biochemical indices, dialysis adequacy and clinical outcomes. METHODS: The effect of Nutrineal was studied retrospectively in 22 patients during the past 30 months. All patients had an albumin level of < 35 g/l prior to commencing Nutrineal, and had either a protein intake < 1.2 g/kg or weight loss of > 5% in the previous 3 months. 19 of the 22 patients underwent an 8-week trial of oral nutritional supplements with no improvement in serum albumin level. Albumin level, normalized protein catabolic rate, weight, Kt/V and creatinine clearance were assessed for all patients prior to Nutrineal and at the end of the study period. RESULTS: The mean time on Nutrineal therapy was 13.6 months (range 6-26 months). There were no reported side effects of the treatment. There was an average of 1 episode of peritonitis per 23 treatment months, and only 1 patient died (4% annually adjusted mortality cf 8.9% on the peritoneal dialysis program as a whole). There was a significant increase in albumin level from 22.45 +/- 0.97 range 14-33 g/l to 25.68 +/- 1.159 range 16-35 g/l (p = 0.0036). Normalized protein catabolic rate increased significantly, from 0.898 +/- 0.053 to 1.085 +/- 0.056 g/kg/day (p = 0.0057). Weight decreased slightly although this did not reach statistical significance. Kt/V and creatinine clearance both decreased significantly, but remained within the adequate range in > 80% of the patients. There was no significant change in residual renal function (mean residual creatinine clearance 3.8 +/- 0.59 ml/min at the start of the study period, cf 3.4 +/- 0.61 ml/min at the end). CONCLUSION: These data suggest that Nutrineal can be used safely and effectively for an extended period of time. Such use is associated with a low mortality rate and a low peritonitis rate, although dialysis adequacy is compromised to a degree.

Graphical display of variability and inter-relationships of pressure signals in children with traumatic brain injury.

A prospective observational study was undertaken to examine time series ICU data of pressure variables (mean arterial pressure (MAP), intracranial pressure (ICP) and cerebral perfusion pressure (CPP)) and relate their variability (SD) to outcome, together with simple graphical displays which could be useful at the ICU bedspace. Forty-three children (aged < 1-15 years) were admitted to the intensive care unit for Regional Neurosurgical Service, Edinburgh, following traumatic brain injury (TBI). The standard deviations from 221,291 validated pressure data measurements (representing three variables) were calculated for the duration of ICP monitoring (and in 48 h epochs from the time of injury). Data were displayed on polygraphs, and several well-defined 'patterns' were described. The standard deviations of MAP, ICP and CPP for the total duration of monitoring were found to be significantly related to survival (p = 0.003, <0.001 and 0.005, respectively), while the SD of ICP alone was strongly related to global recovery (p = 0.008) in the first 48 h post-injury. Patterns in 104 epochs (each of 48 h) were identified. Ninety-two were of the type I (MAP > CPP > ICP) pattern and 12 were of the non-type I pattern. Glasgow Outcome Scale scores at 12 months were significantly related to the dichotomized pattern type (Fisher's exact test p < 0.001 for both alive versus dead and independent versus dependent outcomes). Only one patient with type I pattern died in this series. While variability of ICP during the first 48 h post-injury is predictive of the outcome, the pattern behaviour of three pressure signals gives useful outcome prediction information throughout monitoring. These displays may help interpret some of the plethora of data produced at the bedside.

The general dental status of patients referred to the orthodontic department of the Glasgow Dental Hospital.

A survey of 280 orthodontic referrals to the Glasgow Dental Hospital, consecutively screened for orthodontic needs, revealed that 1 in 5 had untreated caries and more than half had a level of oral hygiene incompatible with wearing an orthodontic appliance. The suitability and motivation of such patients, therefore, must be questioned before prescribing orthodontic treatment.

A reanalysis of the relation between unionization and workplace safety.

Although in the United States it is generally believed that the presence of a union has little effect on workplace safety and health, there is a paucity of empirical evidence to support this perception. In this study, the author attempts to provide a preliminary quantitative basis on which the union's role in this area could be evaluated. Examination of the health and safety records of 26 industries over a 9-year period revealed that in some years, greater union coverage is associated with fewer serious on-the-job accidents. However, the average number of days lost from work due to injury was found to increase in direct relation to an increase in industry unionization. Implications of these findings are discussed.

Fergusobia/Fergusonina-induced Shoot Bud Gall Development on Melaleuca quinquenervia.

Fergusobia nematodes and Fergusonina flies are mutualists that cause a variety of gall types on myrtaceous plant buds and young leaves. The biology of an isolate of the gall complex was studied in its native range in Australia for possible use in southern Florida as a biological control agent against the invasive broad-leaved paperbark tree, Melaleuca quinquenervia. Timed studies with caged Fergusonina flies on young branches of M. quinquenervia revealed that females are synovigenic with lifetime fecundities of 183 +/- 42 (standard error; SE) eggs and longevities of 17 +/- 2 days. None of the male flies but all dissected female flies contained parasitic female nematodes (range = 3-15), nematode eggs (12-112), and nematode juveniles (78-1,750). Female flies deposited eggs (34 +/- 6; 8-77 per bud) and nematode juveniles (114 +/- 15; 44-207 per bud) into bud apices within 15 days. Histological sections of shoot buds suggested that nematodes induce the formation of hypertrophied, uninucleate plant cells prior to fly larval eclosion. Enlarged size, granular cytoplasm, and enlarged nucleus and nucleolus characterized these cells, which appeared similar to those of other species galled by nematodes in the Anguinidae. Observations of ovipositional behavior revealed that female Fergusonina sp. create diagnostic oviposition scars. The presence of these scars may facilitate recognition of host use during specificity screening.

Histological comparisons of fergusobia/fergusonina-induced galls on different myrtaceous hosts.

The putative mutualism between different host-specific Fergusobia nematodes and Fergusonina flies is manifested in a variety of gall types involving shoot or inflorescence buds, individual flower buds, stems, or young leaves in the plant family Myrtaceae. Different types of galls in the early-to-middle stages of development, with host-specific species of Fergusobia/Fergusonina, were collected from Australian members of the subfamily Leptospermoideae (six species of Eucalyptus, two species of Corymbia, and seven species of broad-leaved Melaleuca). Galls were sectioned and histologically examined to assess morphological changes induced by nematode/fly mutualism. The different gall forms were characterized into four broad categories: (i) individual flower bud, (ii) terminal and axial bud, (iii) 'basal rosette' stem, and (iv) flat leaf. Gall morphology in all four types appeared to result from species-specific selection of the oviposition site and timing and number of eggs deposited in a particular plant host. In all cases, early parasitism by Fergusobia/Fergusonina involved several layers of uninucleate, hypertrophied cells lining the lumen of each locule (gall chamber where each fly larva and accompanying nematodes develop). Hypertrophied cells in galls were larger than normal epidermal cells, and each had an enlarged nucleus, nucleolus, and granular cytoplasm that resembled shoot bud gall cells induced by nematodes in the Anguinidae.