diff --git a/python/obitools3/parsers/fasta.pyx b/python/obitools3/parsers/fasta.pyx
index b2f0b43..c619d03 100644
--- a/python/obitools3/parsers/fasta.pyx
+++ b/python/obitools3/parsers/fasta.pyx
@@ -6,7 +6,9 @@ Created on 30 mars 2016
 @author: coissac
 '''
 
-from obitools3.dms.obiseq import Nuc_Seq
+import types
+
+from obitools3.dms.obiseq cimport Nuc_Seq
 
 
 def fastaIterator(lineiterator, 
@@ -48,7 +50,7 @@ def fastaIterator(lineiterator,
     
     while True:
         
-        if read >= ionly:
+        if ionly >= 0 and read >= ionly:
             break
                 
         while skipped < skip :
@@ -79,7 +81,7 @@ def fastaIterator(lineiterator,
     #                       definition,
     #                       tags=tags,
     #                       )
-                
+          # TODO      
         yield { "id"         : ident,
                 "definition" : definition,
                 "sequence"   : sequence,
@@ -105,65 +107,65 @@ def fastaNucIterator(lineiterator,
     cdef list       s
     cdef bytes      sequence
     cdef int        lines_to_skip, ionly, read
-#    cdef OBI_Seq    seq
+    cdef Nuc_Seq    seq
     
     if only is None:
-        ionly=-1
+        ionly = -1
     else:
-        ionly=int(only)
+        ionly = int(only)
 
-    if isinstance(lineiterator,(str,bytes)):
+    if isinstance(lineiterator, (str, bytes)):
         lineiterator=uopen(lineiterator)
     
+    if isinstance(lineiterator, types.GeneratorType):
+        iterator = lineiterator
     if isinstance(lineiterator, LineBuffer):
-        lb=lineiterator
+        iterator = iter(lineiterator)
     else:
-        lb=LineBuffer(lineiterator,buffersize)
-
+        iterator = iter(LineBuffer(lineiterator, buffersize))
 
     skipped = 0
     read = 0
-    i = iter(lb)
     
     if firstline is None:
-        line = next(i)
+        line = next(iterator)
     else:
-        line = firstline
-        
+        line = firstline       
+    
     while True:
-        
-        if read >= ionly:
+                
+        if ionly >= 0 and read >= ionly:
             break
-       
+                
         while skipped < skip :
-            line = next(i)
+            line = next(iterator)
             try:
                 while line[0]!='>':
-                    line = next(i)
+                    line = next(iterator)
             except StopIteration:
                 pass
             skipped += 1
 
         ident,tags,definition = parseHeader(line)
         s = []
-        line = next(i)
-        
+        line = next(iterator)
+    
         try:
             while line[0]!='>':
                 s.append(str2bytes(line)[0:-1])
-                line = next(i)
+                line = next(iterator)
         except StopIteration:
             pass
         
         sequence  = b"".join(s)        
         
-#        seq = 
         seq = Nuc_Seq(ident,
                       sequence,
-                      definition,
-                      None,-1,
-                      tags)
-        
+                      definition=definition,
+                      quality=None,
+                      offset=-1,
+                      tags=tags)
+            
         yield seq
         
 #         yield { "id"         : ident,
diff --git a/python/obitools3/parsers/fastq.pyx b/python/obitools3/parsers/fastq.pyx
index 18bc2c8..83ad7c4 100644
--- a/python/obitools3/parsers/fastq.pyx
+++ b/python/obitools3/parsers/fastq.pyx
@@ -6,7 +6,7 @@ Created on 30 mars 2016
 @author: coissac
 '''
 
-from obitools3.dms.obiseq import Nuc_Seq
+from obitools3.dms.obiseq cimport Nuc_Seq
 
 
 def fastqIterator(lineiterator, 
@@ -74,12 +74,11 @@ def fastqWithQualityIterator(lineiterator,
     else:
         hline = firstline
         
-
     for line in i:
         
-        if read >= ionly:
+        if ionly >= 0 and read >= ionly:
             break
-       
+        
         ident,tags,definition = parseHeader(hline)
         sequence  = str2bytes(line[0:-1])
         next(i)
@@ -87,9 +86,10 @@ def fastqWithQualityIterator(lineiterator,
 
         seq = Nuc_Seq(ident,
                       sequence,
-                      definition,
-                      quality,qualityoffset,
-                      tags)
+                      definition=definition,
+                      quality=quality,
+                      offset=qualityoffset,
+                      tags=tags)
         
         yield seq
 
@@ -149,22 +149,23 @@ def fastqWithoutQualityIterator(lineiterator,
         hline = next(i)
     else:
         hline = firstline
-            
+    
     for line in i:
- 
-        if read >= ionly:
+                
+        if ionly >= 0 and read >= ionly:
             break
        
         ident,tags,definition = parseHeader(hline)
         sequence  = str2bytes(line[0:-1])
         next(i)
         next(i)
-
+                
         seq = Nuc_Seq(ident,
                       sequence,
-                      definition,
-                      None,-1,
-                      tags)
+                      definition=definition,
+                      quality=None,
+                      offset=-1,
+                      tags=tags)
         
         yield seq
 
diff --git a/python/obitools3/parsers/universal.pyx b/python/obitools3/parsers/universal.pyx
index 8d3d0ab..2aa0bb5 100644
--- a/python/obitools3/parsers/universal.pyx
+++ b/python/obitools3/parsers/universal.pyx
@@ -41,11 +41,11 @@ def entryIteratorFactory(lineiterator,
     if isinstance(lineiterator, LineBuffer):
         lb=lineiterator
     else:
-        lb=LineBuffer(lineiterator,buffersize)
-        
+        lb=LineBuffer(lineiterator, buffersize)
+
     i = iter(lb)
         
-    first=next(i)
+    first=next(i)    
 
     format=b"tabular"
     
@@ -61,26 +61,29 @@ def entryIteratorFactory(lineiterator,
         format=b"ecopcrfile"
     elif is_ngsfilter_line(first):
         format=b"ngsfilter"
-        
+    
+    # TODO Temporary fix
+    first=None
+    lineiterator.seek(0)
+    
     if format==b'fasta':
         if seqtype == b'nuc':
             return (fastaNucIterator(lineiterator,
-                                    skip,only,
-                                    first),
+                                    skip=skip,only=only,
+                                    firstline=first,
+                                    buffersize=buffersize),
                     Nuc_Seq)
         else:
             raise NotImplementedError()
     elif format==b'fastq':
             return (fastqIterator(lineiterator,
-                                 skip,only,
-                                 qualityoffset,
-                                 first),
+                                 skip=skip,only=only,
+                                 qualityoffset=qualityoffset,
+                                 noquality=noquality,
+                                 firstline=first,
+                                 buffersize=buffersize),
                     Nuc_Seq)
                     
             
     raise NotImplementedError('File format not yet implemented')
 
-
-        
-
-    
diff --git a/python/obitools3/uri/decode.pyx b/python/obitools3/uri/decode.pyx
index b3b254a..4a3d9cf 100644
--- a/python/obitools3/uri/decode.pyx
+++ b/python/obitools3/uri/decode.pyx
@@ -364,19 +364,22 @@ def open_uri(uri,
             if qualifiers[b"seqtype"]==b"nuc":
                 objclass = Nuc_Seq
                 if format==b"fasta":
-                    iseq = fastaNucIterator(file,skip,only)
+                    iseq = fastaNucIterator(file, 
+                                            skip=skip, 
+                                            only=only)
                 elif format==b"fastq":
                     iseq = fastqIterator(file,
-                                         skip,only,
-                                         offset,
-                                         noquality)
+                                         skip=skip, 
+                                         only=only,
+                                         offset=offset,
+                                         noquality=noquality)
                 else:
                     raise NotImplementedError('Sequence file format not implemented')
             elif qualifiers[b"seqtype"]==b"prot":
                 raise NotImplementedError()
         else:
             iseq,objclass = entryIteratorFactory(file,
-                                          skip,only,
+                                          skip, only,
                                           seqtype,
                                           offset,
                                           noquality,
@@ -388,13 +391,12 @@ def open_uri(uri,
                                           stripwhite,
                                           blanklineskip,
                                           commentchar)
-            
         
-        tmpdms = get_temp_dms()
-            
-        return (file,iseq,objclass,urib)
-                    
-             
+        #tmpdms = get_temp_dms()
+        
+        return (file, iseq, objclass, urib)
+
+
+
+
 
-    
-