Invasive crayfish and crayfish plague on the move: first detection of the plague agent Aphanomyces astaci in the Romanian Danube

Native European crayfish, such as Astacus leptodactylus, are threatened, among other factors, by the crayfish plague agent Aphanomyces astaci, dispersed by invasive North American crayfish. Two of these invaders, Pacifastacus leniusculus and Orconectes limosus, have extended their distribution in the River Danube catchment; the latter was detected for the first time in Romania in 2008. We monitored, at monthly intervals for over 2 yr, occurrence of native A. leptodactylus and invasive O. limosus at 6 sites on the Romanian Danube and checked for the invasive species in 4 of its tributaries. Between January 2009 and March 2011, the relative abundances of O. limosus steadily increased with time, while the native A. leptodactylus dramatically decreased in abundance. O. limosus expanded downstream at a rate of ca. 15 km yr-1; in August 2011, it was already present in the upper 105 km of the Romanian Danube. An agent-specific real-time PCR analyses demonstrated the presence of A. astaci DNA in at least 32% of the analysed invasive (n = 71) and 41% of the native (n = 49) crayfish coexisting in the Danube. Furthermore, A. astaci was also detected in A. leptodactylus captured about 70 km downstream of the O. limosus invasion front (at the time of sampling). Assuming a steady rate of expansion, O. limosus may invade the sensitive Danube delta area in the mid-2060s, even without long-distance dispersal. The crayfish plague agent, however, may reach the delta substantially earlier, through dispersal downstream among populations of native crayfish.     

The concentrations of antioxidant compounds in the hepatopancreas, the gills and muscle of some freshwater crayfish species

We examined the concentrations of vitamin E (vit E), sulphydryl groups (-SH), total protein and protein electrophoretic profiles in the hepatopancreas, the gills and muscle of three freshwater crayfish species: Noble crayfish (Astacus astacus), stone crayfish (Austropotamobius torrentium) and spiny cheek crayfish (Orconectes limosus). Vit E concentration in the hepatopancreas of O. limosus was lower compared to A. astacus, while in the gills of O. limosus it was lower compared to both A. astacus and A. torrentium. The concentration of -SH groups was lower in the hepatopancreas of A. astacus compared to A. torrentium and O. limosus. In the gills of A. astacus and A. torrentium the concentration of -SH groups was higher compared to O. limosus. Protein concentration was higher in the hepatopancreas of A. torrentium compared to A. astacus and O. limosus. A lower protein concentration in muscle of A. torrentium was found compared to O. limosus and A. astacus. Electrophoretic analysis of proteins indicated species and tissue specifities between investigated crayfish species. Our results represent the first study of its kind and provide the basis for future studies that will consider our reported parameters as potential biomarkers for biomonitoring of basic environmental conditions and some anthropogenic impacts.     

The electrolyte content of the body of insects, ascidians, fishes, amphibians and mammals and its dynamics in ontogeny

In animals in which sodium is a predominant cation of the blood serum or haemolymph (rat, newt Triturus vulgaris, sturgeon Acipenser güldenst?dti, herring Clupea pallasi, ascidian Goniocarpa rustica), its content in the body amounts up to a half of the total bulk of electrolytes; in insects with potassium type of the haemolymph, the share of sodium is equal to 6.4%. In animals of the same species, total electrolyte content (sodium, potassium, calcium, magnesium) and the relationship between separate ions were found to be remarkably constant. During ontogenetic development of the sturgeon and herring, as well as in rat embryos beginning from the 15th day of gestation, the ratio between separate cations exhibits significant conservatism.     

Comparative electrophoretic studies of crustacean neurosecretory hyperglycemic and melanophore-stimulating hormones from isolated sinus glands

Summary By disc electrophoresis of sinus gland extracts fromOrconectes limosus, Pacifastacus leniusculus andCarcinus maenas, marked differences in the electrophoretic mobility were demonstrated for the hyperglycemic neurohormone (HGH) from the 3 species. In the astacuran materials, 2 peaks of activity were observed whereas inCarcinus material only 1 peak could be demonstrated with certainty. Melanophore-stimulating activity (MDH) was resolved into several peaks, but 2 predominant peaks with almost identical mobility were observed in all 3 species. Electrophoresis of sinus gland material from the above species and fromHomarus gammarus, Procambarus clarkii, Astacus leptodactylus, A. astacus, Uca pugilator, Cancer magister, Eriocheir sinensis andHemigrapsus oregonensis revealed that all astacuran HGHs fall in one group of substances with low mobility whereas some of the brachyuran hormones (fromCarcinus, Uca andCancer) moved faster. The hormones ofEriocheir andHemigrapsus have mobilities similar to those of the astacuran hormones, but, like the other brachyuran hormones, they are not hyperglycemic in Astacura. HGH was found to be associated with the strongest staining band in the pherograms from all species investigated. It amounts to at least 10% of total sinus gland protein, that is about 0.5 g/gland inOrconectes and 0.6 g/gland inCarcinus. Accumulation of neurosecretory material in the neurohaemal organ is demonstrated by comparison of sinus gland and medulla terminalis extracts. In SDS gels, a large fraction of material (containing the HGH) in the mass range of 6000–8000 daltons is found in the the sinus gland whereas this fraction is barely demonstrable in the medulla terminalis. It was investigated whether cysteine-rich carrier proteins comparable to the vertebrate neurophysins exist in the sinus gland. No positive results were obtained either by aldehyde fuchsin staining of gels or by analysis of³⁵S-labeled sinus gland material. noreactivity in gels after electrophoresis of sinus gland extracts. No positive reaction was obtained with eluates from HGH containing slices. Recent amino acid analyses of HGH (Kleinholz, 1975; Keller and Wunderer, in preparation) do not suggest any similarities between crustacean HGH and vertebrate glucagon.     

Disk electrophoresis fractionation of hemolymph proteins during the metamorphosis of different castes and sexes of Formica pratensis

Using polyacrylamide electrophoresis the proteins of the haemolymph of the different developmental stages can be separated into eight strong and nine weak coloured fractions during the cocoon period of Formica pratensis. The proteins were stained with aniline black and measured quantitatively by a Chromoscan densitometer. The values were compared with those maintained with bovine serum albumin.The total protein content of the haemolymph was calculated as the sum of the different fractions; at maximum it amounts to 2·1 per cent (w/v). The maximum is reached during the pharate pupal stage and during the pigmentation of the eyes; the minimum can be observed at the end of pupal ecdysis. At the beginning of body pigmentation in all the forms the protein content of the haemolymph was very much reduced, especially in workers and females.All fractions change independently resulting in a different composition of the haemolymph proteins in pharate pupae, eclosed pupae, and pharate adults. The slow-running fractions f1, f3, f5, and f6 and the mean bands f8 and f11 are reduced weakly until body pigmentation, and from the eleventh day strongly in both castes. All fractions are reduced during the cocoon period, but mostly the slow-running ones. Only the front band f14 increases to nearly twice that of the protein content. The importance of the changes in the protein fractions for development of different organs and for the synthesis of the haemolymph proteins and the influence of hormones are discussed.     

Effects of starvation on body composition and cold tolerance in the collembolan Orchesella cincta and the isopod Porcellio scaber

The effects of long-term starvation on the body composition of the isopod Porcellio scaber (Latreille) and the collembolan Orchesella cincta (L.) were studied, by determining the body composition in starved and fed animals. A period under summer conditions (19 degrees C, 75% RH and L/D 16/8 photoperiod), was followed by a period under winter conditions (5 degrees C, 75% RH and LD 6/18 photoperiod). O. cincta was held under summer conditions for 3weeks, during which its protein and lipid content decreased, while its water content increased. In P. scaber, the same occurred during the 6weeks they were kept under summer conditions. During subsequent weeks under winter conditions, changes in cold tolerance of the animals were investigated. Cold tolerance and haemolymph osmolality were measured once a week. Starved animals had lower cold tolerance than fed ones. For P. scaber a decreased haemolymph osmolality was found in starved animals compared to fed ones. This is assumed to be caused by a combination of the consumption of carbohydrates out of the haemolymph and of protein reserves and the accumulation of body water. O. cincta appeared to be capable of osmoregulation, as haemolymph osmolality did not differ between starved and fed animals, despite differences in body water content. Decreased cold tolerance in starved animals of both species may be caused by increased water content or, more probably, by the decrease in reserves needed to produce cryoprotective substances.     

Haemolymph protein composition and copper levels in decapod crustaceans

Variations in haemolymph protein composition and concentration, in copper content and copper distribution in the tissue of decapod crustaceans are reviewed. Haemocyanin is the major haemolymph constituent (> 60%); the remaining proteins (in order of concentration) include coagulogen, apohaemocyanin, hormones and antisomes. Moulting, nutritional state, infection, hypoxia and salinity fluctuations are the major factors affecting the relative proportions and total quantities of the haemolymph proteins. With regard to haemocyanin, the changes in concentration during the moult cycle are principally associated with changes in haemolymph volume, rather than with changes in total haemocyanin content due to synthesis or catabolism. The role of the midgut gland in regulating haemolymph copper and haemocyanin concentration has been re-evaluated. More than 50% of the whole body copper load is stored in the haemolymph. In contrast, less than 3% of the copper load resides in the midgut gland. The latter has little potential for regulating haemolymph copper levels, at least in the short term (hours to a few days), though it may be involved in regulating haemocyanin levels over longer periods (weeks to months). The total copper content of the haemolymph remains within a narrow range, except during starvation when levels may decrease. Consequently, variations in the copper content of soft tissues, which constitute only 20% of decapod dry weight, do not significanlty alter whole body copper concentrations. Evidence that copper released following haemocyanin catabolism becomes bound to metallothionein for later use in the resynthesis of haemocyanin is reviewed and found to be inconclusive. The amount of copper that can be stored in this way is trivial compared with the amount of copper required to permit significant changes in haemolymph haemocyanin concentration. Average tissue copper requirements, calculated during the present study, are approx. 4 times higher than previous theoretical estimates.     

Comparative study of the lipid composition of rabbit and lobster sarcoplasmic reticulum.

Sarcoplasmic reticulum (SR) membranes isolated from rabbit and lobster muscles have similar phospholipid classes, but they differ in plasmalogen content. The plasmalogenic species are mostly distributed among phosphatidylethanolamines (PE's) and make up about 62% of the total in rabbit SR and about 46% in lobster membranes. Lobster SR phospholipids contain large amounts of polyunsaturated fatty acids which are present in low amounts in rabbit membranes. The total unsaturated fatty acids of phosphatidylcholines (PC's) represent about 53% and 73% of the total fatty chains for rabbit and lobster SR, respectively. The values found for PE's were about 56% and 64%, respectively. Furthermore, lobster membranes contain significant amounts of PC and PE molecular species with unsaturated fatty acids in positions 1 and 2, whereas rabbit SR contain low amounts.     

Differential effect of fasting on IGF-BPs in serum of young and adult rats and its implication to impaired skin GAG content

During fasting or aging of animals there is a decreased content of skin glycosaminoglycans (GAGs). It has been found that the skin of adult rats contains about 60% of GAGs found in the skin of young animals. Fasting of both groups of animals (young and adult) resulted in decrease of GAG content. However, GAG content in the skin of fasted young rats decreased by 30% and in fasted adult rats by 15% only, compared to fed animals, respectively. The mechanism for the phenomena is not known. We considered insulin-like growth factor-I (IGF-I) as a potential candidate involved in regulation of GAG biosynthesis in both experimental models of animals. Adult rat sera were found to contain about 75% of IGF-I recovered from young rat sera. Fasting of both groups of animals resulted in dramatic decrease in serum IGF-I levels to about 50% of initial values. Since IGF-I activity and IGF-I serum half-life depends on the level of specific IGF-binding proteins (IGFBPs) we determined (i) relationship between main groups of IGFBPs, namely high molecular weight binding proteins (HMWBPs) and low molecular weight binding proteins (LMWBPs) and (ii) the amounts of IGF-I bound to respective proteins in the sera of all experimental animals. Control young rat serum was found to contain about 90% of HMWBPs and about 10% of LMWBPs as determined by ligand binding assay. In contrast, control adult rat serum contained about 60% of HMWBPs and about 40% of LMWBPs. Fasting of both groups of animals resulted in significant increase in serum levels of LMWBPs. Control young rat serum was found to contain about 8% IGF-I bound to LMWBPs while serum of control adult rats contained 18% IGF-I bound to these proteins. In sera of fasted young animals however, about 75% of the bound IGF-I was recovered from LMWBPs (about 60% of total serum IGF-I) while in sera of fasted adult animals only about 56% of the bound IGF-I was recovered from LMWBPs (about 50% of total serum IGF-I). Evidence was provided that during fasting of both groups of animals there is a significant decrease in serum BP-3 and dramatic increase in serum BP-1 concentrations, compared to respective controls. However, the concentration of BP-1 in serum of fasted young rats was increased by about 60 fold while in serum of fasted adult rats only by about 10 fold, compared to respective control animals. Negative correlation between skin GAG content and LMWBPs derived IGF-I during fasting of young (r = - 0.943, p < 0.001) and adult ( r = - 0.571, p < 0.01) rats was found.The data presented suggest that the effects of aging and fasting on decreased skin GAG content may be due to induction of LMWBPs that are known to (i) inhibit IGF-I dependent function and (ii) increase clearance of IGF-I from circulation. However, the effects of fasting are distinct in respect to young and adult rats suggesting that mechanisms involved in regulation of IGF-I bioactivity during aging are more complex that during fasting.     

The neuro-endocrine control of protein metabolism in the migratory grasshopper, Melanoplus sanguinipes

In normal females, distinct fluctuations in the protein content of the fat body and haemolymph are evident during each gonotrophic period. These fluctuations partly reflect changes in the protein requirements of the developing oocytes. Almost one half of the total protein deposited in the mature ovary is sequestered during the final stages of vitellogenesis when protein accumulated in the fat body and haemolymph is rapidly depleted. Although similar amounts of protein are deposited in the ovary during the first and subsequent gonotrophic periods, significantly less extraovarian protein is present throughout the latter periods.The accumulation of large amounts of protein in the fat body and haemolymph of ovariectomized females suggests that most yolk protein is of extraovarian origin. As the total protein content of these insects is comparable to that of vitellogenic females, ovariectomy apparently has no immediate effect on protein synthesis.Allatectomy or cautery of the median neurosecretory cells (mNSC) prevents vitellogenesis. Although protein gradually accumulates in the fat body and haemolymph of allatectomized females, the total protein content of these insects is significantly lower than that of controls. Treatment of allatectomized females with juvenile hormone analogue leads to a temporary but significant increase in the protein content of the fat body. However, the subsequent decline in fat body protein is paralleled by a pronounced increase in the protein content of the ovary. These findings suggest that the corpora allata (CA) stimulate both yolk protein synthesis in the fat body and its uptake into the ovary. The total protein content of mNSC-cauterized females is less than that of allatectomized females. This observation supports the proposal that the mNSC have not only an allatotropic effect but also a direct effect on protein synthesis.     

The chemical composition and energy contents of copepods and cladocerans in relation to their size

The chemical composition and energy contents of four different species of cladocerans, one species of a calenoid copepod, and mixed samples of four species of cyclopoid copepods were quantitatively determined. The relative chemical composition, expressed as a percentage of the total organic matter (excluding chitin) of each of the different species analysed, were very similar. The mean relative composition for all species was 71·2% protein, 9·5% carbohydrates, 19·3% lipids, 16·5% total nitrogen and 2·1% total phosphate–phosphorus. A substantial amount of the total nitrogen was found to be non-protein nitrogen (mean of 23·3% of total nitrogen). The calorific value was calculated from the estimated amounts of proteins, carbohydrates and lipids using conversion factors. The relationship between the calculated organic matter and the chemical oxygen demand (COD) was found to be constant and did not vary much for the different species. The ratio of total organic matter to COD has a mean value of 0·51. Calorific values ranged from 5847 to 6353 cal/g total organic matter. The amounts of chemical substances or energy contents per individual Copepoda or Cladocera were calculated. Regression lines together with their correlation coefficients have been computed to describe the relationship between the amount of chemical constituents and energy contents per individual, and the length of the individual. The results are extensively compared with those given in the literature and differences are discussed.     

Phenoloxidase activity in three commercial bivalve species. Changes due to natural infestation with Perkinsus atlanticus

The phenoloxidase (PO) activity of the haemolymph and haemocytes from three clam species of commercial interest (Ruditapes philippinarum, Chamelea gallina and Tapes decussatus) has been compared. The activity was assayed spectrophotometrically by recording the formation of dopachrome from L-DOPA using sodium dodecyl sulphate, laminarin, trypsin or lipopolysaccharide as elicitors. Fewer PO units were observed in the haemolymph from T. decussatus than in the haemolymph from R. philippinarum, while the highest values were found in C. gallina. In all cases the activity was only significantly increased when sodium dodecyl sulphate was used as elicitor. PO activity in the haemocytes of all three clam species showed a very similar pattern to that found in the haemolymph from the same species. Furthermore, T. decussatus naturally parasitized by Perkinsus atlanticus (Protozoa, Apicomplexa) was used to study the influence of such infestation on PO activity, which was found to increase significantly in both haemolymph and haemocytes compared with non-infected (control) samples. PO activity in the haemocytes and in the haemolymph was higher when the level of parasitization was low or medium, respectively, and SDS was used as elicitor. No statistically significant differences were observed when the parasitization level was high. The present work constitutes the first report on the influence of this parasite on PO activity in haemolymph and haemocytes from T. decussatus.     

Osmoregulation in Onymacris rugatipennis, a free-ranging tenebrionid beetle from the Namib Desert.

Haemolymph levels of organic and inorganic constituents were investigated in the tenebrionid Onymacris rugatipennis during dehydration and rehydration. The major osmolar effectors are sodium (26%), chloride (24%), amino acids (18%), and sugars (11%); regulation of haemolymph osmotic pressure (OP) during dehydration is effected largely by a reduction in the haemolymph content of these constituents. Changes in amino acid levels are not the result of interchanges with soluble protein. During rehydration, the main contributors to osmoregulation are sodium (26%), chloride (24%), and an increase in haemolymph solute(s) not measured in this study (31%). Of the sodium removed from the haemolymph during dehydration, 21.2% was excreted. Faecal losses of potassium during dehydration far exceeded the amounts removed from the haemolymph; however, haemolymph potassium levels were strongly regulated during rehydration. Regulatory efficiency increases as desiccation proceeds, and is greatest only when this species is severely challenged.     

Seasonal changes in reproductive function of the rainbow trout (Salmo gairdneri)

The sequential changes in serum oestradiol 17β (measured by specific radioimmunoassay), vitellogenin (measured by phosphoprotein phosphorus content) and total calcium (measured by fluorimetry) in male and female rainbow trout under a simulated natural photoperiod cycle were investigated. Resting levels of 130 pg/ml serum oestradiol in both male and female fish were found in April and May. In the female, levels reached a peak of 4800 pg/ml in October, and almost returned to resting levels just prior to spawning in mid-January. No significant change from resting levels was seen in the male fish.
In both male and female fish levels of 25 μg/ml serum phosphoprotein phosphorus and 10–14 mg % total serum calcium were found from April to July. Coincident with the rise in oestradiol 17β, in the females serum levels of phospho-protein phosphorus and total calcium increased to 400 uβg/ml and 58 mg% respectively just prior to spawning. In the males no significant change in either of these values was observed throughout the cycle. These results strongly support the hypothesis that photoperiod is the major factor in the environmental control of reproductive activity in the rainbow trout.     

Specific UV-absorbancy of pure rRNA isolated from trout liver as a standard for the quantification of ribonucleic acid from fish tissues

1. Lyophilized crude rRNA from trout (Salmo gairdneri R.) liver was composed (w/w) of 2.9% protein, traces of DNA and glycogen, 13% water and 83% pure rRNA. The RNA content was derived from the discrepancy between effectively found (8.1%, w/w) and theoretical phosphorus content (9.6%, w/w). 2. The theoretical phosphorus content was calculated on the basis of the molar distribution of nucleotides in rRNA (UMP:GMP:AMP:CMP = 24.7%:30%:19.5%:25.8%), established upon cation exchange chromatography of alkali-degraded crude rRNA. 3. The extinction coefficient (corrected for moisture and none-ribonucleic acid contaminants) of pure rRNA in 0.2 N PCA after digestion in 0.3 N KOH at 37 degrees C for 90 min is 361 in terms of E1%260. That of undegraded, pure rRNA in water amounts to 279.     

Reactional behavior of young crayfish towards metallic fons (Zn, Cu, Pb, and Cr): effect of temperature and sediments]

Reactional behaviour of two species of young crayfishes to different concentrations in chlorures (Zn, Cu, Pb and Cr) in option with breeding water is analysed. Discrimination capacity is more feeble with O. limosus. Physiological differences are confirmed by the raising of temperature or the presence of sediments. One interpretation of the ecological repartition of the two species A. pallipes and O. limosus is proposed on this basis.     

Changes in vitellin and other yolk proteins during embryonic development in the silkworm, Bombyx mori

Changes in the amounts of vitellin and other yolk proteins of the eggs of the silkworm, Bombyx mori were investigated during embryonic development using polyacrylamide gel electrophoresis and immunotitration techniques. In the newly laid eggs, soluble proteins were separated into at least nine bands after electrophoresis. The major band was identified as vitellin, accounting for about 40% of the total proteins. The four predominant bands including vitellin exhibited the same mobility as the proteins of haemolymph, but one other major band was specific to the eggs, accounting for about 20% of the proteins.During embryonic differentiation 6–7 days after oviposition, the total protein content did not decrease and the banding patterns and their relative concentrations remained unchanged as a whole. However the concentration of the egg specific protein steadily decreased. During subsequent larval differentiation until hatching, the total proteins were utilized to about 50% of the initial levels: the rapid degradation was observed in almost every species of proteins.An immunotitration experiment further demonstrated that vitellin was not utlilized during embryonic differentiation but was consumed markedly during larval differentiation. However, about 30% of initial level was reserved in the newly hatched larvae. Such a prolonged persistence of vitellin is discussed in relation to protein metabolism during embryonic development in silkworms.     

Vitellogenesis by the American cockroach: Electrophoretic and antigenic characterization of haemolymph and oöcyte proteins

Several peptides have been found in the haemolymph which are antigenically similar to peptides found in the terminal oöcyte during vitellogenesis. There appear to be two major peptides. labeled A and D, in the oöcyte with a stoichiometry of A₂D₁. These two proteins are also found in the haemolymph. Several other prominent proteins found in the haemolymph during the six day cycle are not found to be immunochemically similar to yolk antisera.The possibility of a precursor protein found in both the haemolymph and terminal oöcyte with a molecular weight of 189,000 is discussed.     

Diversity in the Content of Some Nutritional Components in Husked Seeds of Three Wild Rice Species and Rice Varieties in Yunnan Province of China

In addition to rice (Oryza sativa L.) cultivars, there are three wild rice species, namely O.rufipogon Griff, O. officinalis Wall and O. granulata Baill, in Yunnan Province, China. Each species has different subtypes and ecological distributions. Yunnan wild rice species are excellent genetic resources for developing new rice cultivars. The nutritional components of the husked seeds of wild rice have not been investigated thus far. Herein, we report on the contents of total protein, starch, amylose, 17 amino acids, and five macro and five trace mineral elements in husked seeds from three wild rice species and six O. sativa cultivars. The mean (± SD) protein content in the husked rice of O. rufipogon, O. officinalis, and O. granulata was (14.5 ± 0.6)%, (16.3 ± 1. 1)%, and (15.3 ± 0.5)%, respectively. O. officinalis Ⅲ originating from Gengma had the highest protein content (19.3%). In contrast, the average protein content of six O. sativa cultivars was only 9.15%. The total content of 17 amino acids of three wild rice species was 30%-50% higher than that of the six cultivars. Tyrosine, lysine, and valine content in the three wild rice species was 34%-209% higher than that of the cultivars. However, the difference in total starch content among different O. sativa varieties or types of wild rice species was very small. The average amylose content of O. rufipogon, O. officinalis,and O. granulata was 12.0%, 9.7%, and 11.3%, respectively, much lower than that of the indica and japonica varieties (14.37%-17.17%) but much higher than that of the glutinous rice cultivars (3.89%). The sulfur, phosphorus, magnesium, zinc, and ferrite content in the three wild rice species was 30%-158% higher than that of the six cultivars. The considerable difference in some nutritional components among wild rice species and O. sativa cultivars represents a wide biodiversity of Yunnan Oryza species. Based on the results of the present study, it is predicted that some good genetic traits, especially high protein and ideal amylose content, of Yunnan wild rice species may be useful in improving the nutritional value of rice. This is the first report regarding the amino acid, mineral element, protein and amylose content of husked seeds of some Yunnan wild rice species that have important genetic characteristics for rice quality and nutritional value.     

The developmental profiles of two major haemolymph proteins from Drosophila melanogaster.

There are four major protein species in the haemolymph of the late 3rd instar of Drosophila. Two of these, LSP-1 and LSP-2, have been studied in detail. Larvae, pupae, and flies of different ages were measured for wet weight, total extractable protein and using an immunoassay, the amounts of LSP-1 and LSP-2. The synthesis of both proteins begins after the 2nd larval ecdysis and at puparium formation they represent 9% and 1.5% of total extractable protein. This value remains constant during the first part of metamorphosis, then falls rapidly. The function of these proteins and their suitability as systems for the study of gene control and protein synthesis in Drosophila are discussed.