Seasonal reproductive cycles in three commercially exploited fishes from the slope waters off New Zealand

Reproductive cycles were investigated in orange roughy, Hoplostethus atlanticus , smooth oreo, Pseudocyttus maculatus , and black oreo dory, Allocyttus sp., from mid-slope waters (600–1300 m) around New Zealand from 1982 to 1985. Orange roughly displayed a mid-winter spawning period in July and August, whereas both dory species spawned in November and December. In all three species, the timing of spawning was consistent from year to year. Ovarian development in orange roughy and black oreo dory was found to be synchronous, with a single clutch of oocytes being matured for each spawning season. In males, testes of a given macroscopic stage were dominated by a single gamete stage, supporting the existence of a brief rather than prolonged spawning period. The possible relationship of spawning period to seasonal changes in the productivity of the surface water is discussed.     

The relationship of ocular morphology to feeding modes and activity periods in shallow marine teleosts from New Zealand

Synopsis Thirty one species of shallow water teleosts were captured from the NE coast of New Zealand. Ocular morphology was assessed in terms of eye size, pupil shape, theoretical sensitivity and acuity based on retinal morphology, and regional distribution of photoreceptors within the retina. Eye size was relatively or absolutely larger in carnivores than herbivores. Diurnal planktivores and nocturnal species of small body size maximise vision by having relatively large eyes. Anterior aphakic spaces were present in most of the species examined, and 25% of the species also had posterior aphakic spaces. Theoretical sensitivity was generally higher among nocturnal than diurnal species, however, a number of benthic and pelagic carnivores showed retinal specialization for enhanced sensitivity. Diurnal species displayed high spatial acuity, with maximum acuity occurring in carnivorous species. Crepuscular species had either high or low acuity, whereas that of nocturnal species was generally lower than in diurnal species. Ten species displayed regional variation in rod density, with crepuscular and nocturnal species showing streaks of high rod density in the retina. Eleven species of carnivores displayed regional variation in cone density, with highest density usually occurring in the caudal part of the retina. In most of the species with areas of high cone density, there was a forward visual axis that coincided with the location of the aphakic space, suggestive of accomodation along that axis.     

Interannual variation in the reproductive cycle of the New Zealand snapper Pagrus auratus (Bloch & Schneider) (Sparidae)

Changes in reproductive condition in the New Zealand snapper Pagrus auratus (Bloch & Schneider) were monitored in a wild population over three successive years. Recrudescence occurred in spring with spawning beginning in October and continuing for 3 to 5 months. The initiation of spawning varied by up to 3 weeks and was associated with sea surface temperatures of 15–16° C. Theconclusion of spawning was associated with temperatures of 19–21° C but showed greater interannual variation than the onset of spawning. Changes in the gonadosomatic index were accompanied by parallel changes in hepatosomatic index in females but not males, reflecting the role of the liver in vitellogenesis in females.     

The effect of bacterial strain and temperature changes on the nitrogenase activity of Lotus pedunculatus root nodules

After 40 days of growth at 25°C, Lotus pedunculatus cav., cv. Maku plants infected with Rhizobium loti strain NZP2037 displayed similar relative growth rates but had twice the nodule mass and only one third the whole plant dry weight of plants infected with Bradyrhizobium sp. (Lotus) strain CC814s. In the NZP2037 symbiosis, the rate of CO₂ evolution (per g dry weight of nodulated root) was 1.6 times as high as that in the CC814s symbiosis while the rate of C₂H₂ reduction (per g dry weight of nodule) was only 48% of that in the CC814s symbiosis. Studies of the effect of short term temperature changes on the gas exchange characteristics (CO₂ and H₂ evolution, C₂H₂ reduction) of these symbioses revealed wide differences in the optima for C₂H₂ reduction. Nodules infected with NZP2037 displayed maximal C₂H₂ reduction rates [157 μmol (g dry weight nodule)^?1 h^?1] at 12°C, whereas nodules infected with CC814s were optimal at 30°C [208 μmol (g dry weight nodule)^?1 h^?1]. These short term studies suggested that differences in temperature optima for N₂ may have partially accounted for the poorer effectivity, at 25°C, of strain NZP2037 when compared with strain CC-814s. The relative efficiency [RE = 1 – (H₂ evolution/C₂H₂ reduction)] of N₂ fixation varied widely with temperature in the two symbioses, but there was a general trend toward higher RE with lower temperatures. The ratio of CO₂ evolution: C₂H₂ reduction (mol/mol) in nodulated roots infected with CC814s was constant (ca 10 CO₂/C₂H₂) between 5°C and 30°C, whereas in plants infected with NZP2037 it reached a minimal value of 3.3 CO₂/C₂H₂ at 10°C and was 19 CO₂/C₂H₂ at the growing temperature (25°C).     

Airway cellularity, lipid laden macrophages and microbiology of gastric juice and airways in children with reflux oesophagitis

Background and methods

Human metapneumovirus (hMPV) is a recently discovered respiratory virus associated with bronchiolitis, pneumonia, croup and exacerbations of asthma. Since respiratory viruses are frequently detected in patients with acute exacerbations of COPD (AE-COPD) it was our aim to investigate the frequency of hMPV detection in a prospective cohort of hospitalized patients with AE-COPD compared to patients with stable COPD and to smokers without by means of quantitative real-time RT-PCR.

Results

We analysed nasal lavage and induced sputum of 130 patients with AE-COPD, 65 patients with stable COPD and 34 smokers without COPD. HMPV was detected in 3/130 (2.3%) AE-COPD patients with a mean of 6.5 × 10⁵ viral copies/ml in nasal lavage and 1.88 × 10⁵ viral copies/ml in induced sputum. It was not found in patients with stable COPD or smokers without COPD.

Conclusion

HMPV is only found in a very small number of patients with AE-COPD. However it should be considered as a further possible viral trigger of AE-COPD because asymptomatic carriage is unlikely.     

Preadipocyte Recruitment in Stromal Vascular Cultures After Depletion of Committed Preadipocytes by Immunocytotoxicity

Glucocorticoids or the glucocorticoid analog dexamethasone (DEX) enhances the differentiation of preadipocytes in the presence of insulin and influences preadipocyte proliferation. The purpose of the present study was to determine if DEX can induce the recruitment of preadipocytes. Using monoclonal antibodies for complement-mediated cytotoxicity, preadipocytes were removed from porcine stromal vascular (S-V) cell cultures. Our experiments demonstrated for the first time that after removal of preadipocytes by cytotoxicity, preadipocytes or fat cells could be induced by DEX or DEX plus insulin but not by insulin alone. However, many more fat cells were induced (258 ± 15/unit area) when DEX was added with fetal bovine serum (FBS) followed with insulin treatment, compared to DEX with insulin (21.3 ± 5.1/ unit area) after removal of preadipocytes. Immunocyto-chemistry with AD-3, a preadipocyte marker, showed that DEX with FBS for 3 days after seeding (i.e., the proliferation phase) produced many more preadipocytes (AD-3 positive, 223 ± 45/unit area) than FBS alone (10.5 ± 1.4/unit area). Bromodeoxyuridine (BrdU) incorporation assays demonstrated that the efficiency of DEX with FBS (i.e., during proliferation) was mitosis dependent. Accordingly, we conclude that: porcine S-V cultures contain preadipocytes at different stages of differentiation and that DEX induced early preadipocyte differentiation depends on mitosis.     

Involvement of a phospholipase C in the hemolytic activity of a clinical strain of <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis>

Background  

Pseudomonas fluorescens is a ubiquitous Gram-negative bacterium frequently encountered in hospitals as a contaminant of injectable material and surfaces. This psychrotrophic bacterium, commonly described as unable to grow at temperatures above 32°C, is now considered non pathogenic. We studied a recently identified clinical strain of P. fluorescens biovar I, MFN1032, which is considered to cause human lung infection and can grow at 37°C in laboratory conditions.     

Direct Development of the Visual System of the Coral Reef Teleost, The Spiny Damsel, Acanthochromis polyacanthus

Unlike most marine teleosts, the coral reef-dwelling spiny damsel, Acanthochromis polyacanthus, lacks a pelagic larva dispersal phase and represents one of few examples of self recruitment onto a natal reef by a marine teleost immediately after hatching. Benthic eggs are protected by the parents, and upon hatching the young remain under parental care for several months. Visual morphogenesis of spiny damsel embryos and juveniles was examined to evaluate the potential visual capabilities of the young after emergence onto the reef. The optic primordia were visible in the embryo as hollow spheres of undifferentiated neuroblasts 2 days after fertilization (daf). Visual morphogenesis proceeded rapidly thereafter in the embryo such that at hatching (between 10 and 12daf) gross visual morphology was consistent with that reported in the majority of juvenile marine teleosts, reflecting direct development of the retina of the spiny damsel within the egg. At hatching, the outer nuclear layer comprised 2 classes of photoreceptors; cones and rods. Tangential sections of the retina revealed a square cone mosaic in which 4 double cones surrounded a single cone. This arrangement remained unchanged in all later life history intervals examined. Absolute eye size was large compared to larvae of marine pelagic spawners. Eye and lens diameters increased from 0.69 and 0.23mm, respectively, on the day of hatching (12daf), to 3.77 and 1.52mm, respectively, in a fish 131daf. Angular density of cones increased from 0.25 cones 10 visual arc^–1 in an embryo 8daf, to 1.14 cones 10 visual arc^–1 in a fish 131daf, demonstrating the potential for significant increase in spatial resolution with increasing eye size. Convergence ratios of cones to ganglion cells remained relatively constant from the time of hatching, suggesting that the determinate ganglion cell photopic receptive field was established early in development. The increase in the convergence ratios of rods: ganglion cells from 1.4 in the late stages of embryogenesis (10daf; 2 days prior to hatching) to 4.9 in a fish 103daf, demonstrated increasing scotopic ganglion cell receptive field size, with increasing age. This was a result of rod cell addition with growth. An increase in the angular density of rods from 0.18 rods 10 visual arc^–1 in an embryo 8daf, to 4.07 rods 10 visual arc^–1 in a fish 131daf, and the increase in mean scotopic light path-length from 13.3±1.1m in an embryo 8dpf, to 55±5.2m a fish 22dpf, collectively indicate the potential for increasing scotopic sensitivity during growth. On the basis of visual morphology it is predicted that newly hatched spiny damsel juveniles have substantially greater visual capabilities than first feeding larvae with a pelagic dispersal phase. In addition, we propose that the developmental trajectory of the spiny damsel is different from that of pelagic dispersing larvae and does not simply reflect displacement along a common developmental continuum by an extended embryonic duration.