Infection of the gonads of Glaucosoma hebvaicum by the nematode Philometva lateolabracis: occurrence and host response

The prevalence of infection of the West Australian dhufish Glaucosoma hebraicum off the lower west coast of Australia by Philometra lateolabracis was greater among females than males, which contrasts with the situation with Pagrus auratus in waters off New Zealand. Live P. lateolabracis were represented solely by females and were found only in the gonads of fish of mature size ( L ₅₀ at first maturity = c . 300 mm) caught between December and April and thus during the spawning period of dhufish. Since the gonads were largest during that period, they, and particularly ovaries, would provide an abundant food source in the form of blood. The prevalence of the parasite (live + dead individuals) increased with host body size to reach a maximum of c . 80% in the 700–799 mm length class of females and c . 50% in the largest length class of males. During the spawning period of G hebraicum, P. lateolabracis developed from small, non-gravid females to large gravid females, representing an increase in mass of more than 200 times. The maximum length of P. lateolabracis (470 mm) in G hebraicum is the greatest yet recorded for this species. Gonadosomatic indices provided no evidence that infection by P. lateolabracis leads to a conspicuous atrophy of the ovaries, which contrasts with the situation with the gonads of some of the teleosts infected by Philometra species, and presumably reflects, in part, the small volume of the ovary occupied by P. lateolabracis (c . 3%) and the low intensity of infection (mean = 2.0, maximum = 7). Although the presence of live P. lateolabracis did not stimulate an obvious tissue response by the ovaries during the spawning period of G. hebraicum , both the dead and any live parasites that remain after spawning become encapsulated in fibrous tissue.     

Treatment of osteoporosis with human parathyroid peptide and observations on effect of sodium fluoride.

OBJECTIVE--To evaluate the need for a randomised study of treatment of spinal osteoporosis with human parathyroid peptide in the secondary prevention of crush fractures; to study the effect of human parathyroid hormone peptide 1-34 plus sex hormones on vertebral body cancellous bone; and, separately, to determine the effect of relatively low doses of sodium fluoride plus calcium on spinal bone mineral density. DESIGN--Open study of patients with primary or postmenopausal osteoporosis. All patients had serial bone densitometry of the spine by quantitative computed tomography and dual photon absorptiometry as well as serial densitometry of the radial midshaft (cortical) and radial distal (trabecular) bone by quantitative computed tomography. Changes in the spinal bone not forming the spongiosa of the vertebral bodies ("cortical" bone) were determined from the difference between the two axial measurements, after correction to the same units of measurement. SETTING--Northwick Park Hospital and Medical Research Council Clinical Research Centre. PATIENTS--24 Patients who fulfilled the conventional criteria for type 1 (vertebral) osteoporosis not secondary to recognised causes other than sex hormone deficiency and with at least one crush or wedge vertebral fracture and a spinal bone density (quantitative computed tomography) less than 80 mg/cm3 or two or more fractures. Twelve patients received human parathyroid peptide and 12 sodium fluoride; they were not randomised. MAIN OUTCOME MEASURES--Trends in axial and peripheral bone mass values determined by linear, time dependent regression analyses. RESULTS--The patients receiving the peptide showed a substantial increase in vertebral spongiosa (mean 25.6 mg/cm2 two years after the start of treatment). No significant changes were seen in spinal cortical or radial bone density. The patients receiving sodium fluoride showed roughly equal increases in cancellous and cortical bone over the same period (mean increase in vertebral spongiosa 16.1 mg/cm3). No significant changes were seen in radial bone. CONCLUSIONS--Treatment of postmenopausal women with human parathyroid peptide selectively increases spinal cancellous bone density by amounts that may prove useful in secondary prevention. Peptide treatment should now be tested in a randomised study in which the important end point is prevention of fractures as the usefulness of sodium fluoride in this context is doubtful.     

Prolapsus vaginae in the IIIVO/JU rabbit

In a specified pathogen free (SPF) breeding colony of IIIVO/JU rabbits 8 cases of prolapsus vaginae occurred in 5 years. Clinically the animals were in shock. Haematocrits ranged from 9 to 15%. The prolapses started from the submucosal layer of the proximal part of the vestibulum vaginae. The prolapsed tissue consisted of over-expanded blood-sinuses. Between the sinuses signs of an inflammatory reaction were present. All 8 animals were in a period of increasing sexual activity when the prolapse developed. The 8 rabbits were closely related, indicating a possible hereditary defect.     

Microbial composition affects the functioning of estuarine sediments

Although microorganisms largely drive many ecosystem processes, the relationship between microbial composition and their functioning remains unclear. To tease apart the effects of composition and the environment directly, microbial composition must be manipulated and maintained, ideally in a natural ecosystem. In this study, we aimed to test whether variability in microbial composition affects functional processes in a field setting, by reciprocally transplanting riverbed sediments between low- and high-salinity locations along the Nonesuch River (Maine, USA). We placed the sediments into microbial ‘cages'' to prevent the migration of microorganisms, while allowing the sediments to experience the abiotic conditions of the surroundings. We performed two experiments, short- (1 week) and long-term (7 weeks) reciprocal transplants, after which we assayed a variety of functional processes in the cages. In both experiments, we examined the composition of bacteria generally (targeting the 16S rDNA gene) and sulfate-reducing bacteria (SRB) specifically (targeting the dsrAB gene) using terminal restriction fragment length polymorphism (T-RFLP). In the short-term experiment, sediment processes (CO₂ production, CH₄ flux, nitrification and enzyme activities) depended on both the sediment''s origin (reflecting differences in microbial composition between salt and freshwater sediments) and the surrounding environment. In the long-term experiment, general bacterial composition (but not SRB composition) shifted in response to their new environment, and this composition was significantly correlated with sediment functioning. Further, sediment origin had a diminished effect, relative to the short-term experiment, on sediment processes. Overall, this study provides direct evidence that microbial composition directly affects functional processes in these sediments.     

Incidence of HIV in Windhoek, Namibia: demographic and socio-economic associations

Objective

To estimate HIV incidence and prevalence in Windhoek, Namibia and to analyze socio-economic factors related to HIV infection.

Method

In 2006/7, baseline surveys were performed with 1,753 private households living in the greater Windhoek area; follow-up visits took place in 2008 and 2009. Face-to-face socio-economic questionnaires were administrated by trained interviewers; biomedical markers were collected by nurses; GPS codes of household residences were recorded.

Results

The HIV prevalence in the population (aged>12 years) was 11.8% in 2006/7 and 14.6% in 2009. HIV incidence between 2007 and 2009 was 2.4 per 100 person year (95%CI = 1.9–2.9). HIV incidence and prevalence were higher in female populations. HIV incidence appeared non-associated with any socioeconomic factor, indicating universal risk for the population. For women a positive trend was found between low per-capita consumption and HIV acquisition. A HIV knowledge score was strongly associated with HIV incidence for both men and women. High HIV prevalence and incidence was concentrated in the north-western part of the city, an area with lower HIV knowledge, higher HIV risk perception and lower per-capita consumption.

Discussion

The HIV incidence and prevalence figures do not suggest a declining epidemic in Windhoek. Higher vulnerability of women is recorded, most likely related to economic dependency and increasing transactional sex in Namibia. The lack of relation between HIV incidence and socio-economic factors confirms HIV risks for the overall urban community. Appropriate knowledge is strongly associated to lower HIV incidence and prevalence, underscoring the importance of continuous information and education activities for prevention of infection. Geographical areas were identified that would require prioritized HIV campaigning.     

Diminished transmission of drug resistant HIV-1 variants with reduced replication capacity in a human transmission model

Background

Different patterns of drug resistance are observed in treated and therapy naïve HIV-1 infected populations. Especially the NRTI-related M184I/V variants, which are among the most frequently encountered mutations in treated patients, are underrepresented in the antiretroviral naïve population. M184I/V mutations are known to have a profound effect on viral replication and tend to revert over time in the new host. However it is debated whether a diminished transmission efficacy of HIV variants with a reduced replication capacity can also contribute to the observed discrepancy in genotypic patterns.As dendritic cells (DCs) play a pivotal role in HIV-1 transmission, we used a model containing primary human Langerhans cells (LCs) and DCs to compare the transmission efficacy M184 variants (HIV-M184V/I/T) to HIV wild type (HIV-WT). As control, we used HIV harboring the NNRTI mutation K103N (HIV-K103N) which has a minor effect on replication and is found at a similar prevalence in treated and untreated individuals.

Results

In comparison to HIV-WT, the HIV-M184 variants were less efficiently transmitted to CCR5⁺ Jurkat T cells by both LCs and DCs. The transmission rate of HIV-K103N was slightly reduced to HIV-WT in LCs and even higher than HIV-WT in DCs. Replication experiments in CCR5⁺ Jurkat T cells revealed no apparent differences in replication capacity between the mutant viruses and HIV-WT. However, viral replication in LCs and DCs was in concordance with the transmission results; replication by the HIV-M184 variants was lower than replication by HIV-WT, and the level of replication of HIV-K103N was intermediate for LCs and higher than HIV-WT for DCs.

Conclusions

Our data demonstrate that drug resistant M184-variants display a reduced replication capacity in LCs and DCs which directly impairs their transmission efficacy. As such, diminished transmission efficacy may contribute to the lower prevalence of drug resistant variants in therapy naive individuals.

     

Physiological methods to study biofilm disinfection

This report reviews the development of a rapidin situ approach to study the physiological responses of bacteria within biofilms to disinfectants. One method utilized direct viable counts (DVC) to assess the disinfection efficacy when thin biofilms were exposed to chlorine or monochloramine. Results obtained using the DVC method were one log higher than plate count (PC) estimates of the surviving population after disinfection. Other methods incorporated the use of fluorogenic stains, a cryotomy technique to yield thin (5-m) sections of biofilm communities and examination by fluorescence microscopy. The fluorogenic stains used in this approach included 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), which indicates cellular electron transport activity and Rhodamine 123, which responds specifically to proton motive force. The use of these stains allowed the microscopic discrimination of physiologically active bacteria as well as heterogeneities of active cells within thicker biofilms. The results of experiments using these techniques with pure culture and binary population biofilms on stainless steel coupons indicated biocidal activity of chlorine-based disinfectants occurred initially at the bulk-fluid interface of the communities and progressed toward the substratum. This approach provided a unique opportunity to describe the spatial response of bacteria within biofilms to antimicrobial agents and address mechanisms explaining their comparative resistance to disinfection in a way that has not been possible using traditional approaches. Results obtained using this alternative approach were also consistently higher than PC data following disinfection. These observations suggest that traditional methods involving biofilm removal and bacterial enumeration by colony formation overestimate biocide efficacy. Hence the alternative approach described here more accurately indicates the ability of bacteria surviving disinfection to recover and grow as well as demonstrate spatial heterogeneities in cellular physiological activities within biofilms.     

Reproductive Biology and Protandrous Hermaphroditism in Acanthopagrus latus

Detailed macroscopic and histological studies of the gonads of a full size and age range of Acanthopagrus latus from each season in Shark Bay, Western Australia, demonstrate that this species is a protandrous hermaphrodite in this large subtropical embayment. Although our scheme for the changes that occur in the ovotestes of A. latus during life is not consistent with some of the conclusions drawn for this species elsewhere, it is similar to that of Pollock (1985 J. Fish. Biol. 26: 301–311) for the congeneric Acanthopagrus australis. The ovotestes of males develop from gonads which contain substantial amounts of both testicular and ovarian tissue. The testicular component of the ovotestes of all males regresses markedly after spawning. During the next spawning season, the ovotestes either become gonads in which the testicular zone again predominates and contains spermatids and spermatozoa (functional males), or gonads in which the ovarian zone now predominates and contains mature oocytes (functional females). Once a fish has become a functional female, it remains a female throughout the rest of its life. In Shark Bay, A. latustypically spawns on a limited number of occasions during a short period in late winter and early spring and has determinate fecundity. The mean potential annual fecundity was ca. 2000000. The total length of 245mm, at which, during the spawning period, 50% of A. latus become identifiable as males, is very similar to the current minimum legal length (MLL) of 250mm, which corresponds to an age of ca. 2.5 years less than that at which 50% of males become females. Thus, although the spawning potential ratio suggests that the present fishing pressure is sustainable, the current MLL should be reviewed if recreational fishing pressure continues to increase.     

Comparisons between the biology of two co-occurring species of whiting (Sillaginidae) in a large marine embayment

Synopsis We compare the biology of the tropical species Sillago analis and the temperate species Sillago schomburgkii in Shark Bay, a large subtropical marine embayment on the west coast of Australia. This environment constitutes approximately the southernmost and northernmost limits of the distributions of these two species, respectively. The annuli visible in sectioned otoliths of S. analis and S. schomburgkii form annually. Their numbers were thus used to age the individuals of these two species, which are morphologically very similar and live in the same habitats. Although the growth rates of S. analis and S. schomburgkii are very similar until maturity is attained, they subsequently diverge, with S. schomburgkii investing relatively more energy into somatic growth. The maximum total lengths and ages of both the females (320 mm, 6 years) and males (283 mm, 8 years) of S. analis were not as great as those of the females (383 mm, 9 years) and males (302 mm, 9 years) of S. schomburgkii. In Shark Bay, S. schomburgkii spawns earlier and longer than S. analis, i.e. August–December vs. January–March, which would result in the juveniles of these two species recruiting into nursery areas at different times. In addition, S. schomburgkii spawns earlier and for longer in Shark Bay than in temperate marine waters 800 km further south, presumably reflecting the fact that, in that subtropical embayment, water temperatures over which this species typically spawns are attained earlier and last for longer. However, although environmental conditions in Shark Bay and those temperate marine waters differ markedly, the growth of the corresponding sexes of S. schomburgkii in these two water bodies is similar.